Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
HMSCGC856.07no.163cop. 2
lege of
)ceanic and Atmospheric Sciences
0L(j
4-6 N
A- r' T. IXCAN
I
Physical Oceanographic Observationsfrom the Resolute 1995 Ice Camp,
Barrow Strait, April/May 1995
by
G. Crawford and L. Padman
Oregon State University
MARILYN POTTS GUIN LIBRARY
HATFIELD MARINE SCIENCE CENTER
OREGON STATE UNIVERSITY
NEWPORT, OREGON 97365
College of Oceanic & Atmospheric SciencesOregon State University
Corvallis, OR 97331-5503
Data Report 163COAS Reference No. 97-1
February 1997
PHYSICAL OCEANOGRAPHIC OBSERVATIONS FROM THERESOLUTE 1995 ICE CAMP, BARROW STRAIT,
APRIUMAY 1995
Greg Crawford and Laurie Padman
College of Oceanic and Atmospheric SciencesOregon State University104 Ocean Admin. Bldg.
Corvallis, OR 97331-5503
2/7/97
Sponsor: Office of Polar Programs, National Science Foundation
Grants: DPP-9224303 and OPP-9530916
Data Report #163
COAS Reference No. 97-1
1
PROJECT SUMMARY
A multidisciplinary oceanographic research program was carried out by US and Canadian
investigators in the spring of 1995 in the Canadian Arctic, near Lowther Island in Barrow Strait. The
program, referred to here as Resolute 95 (or Res95), had a variety of objectives, including detailed
examination of the mechanisms responsible for vertical mixing, and assessing the relative
importance of nutrient and light limitation on algal growth under ice.
This report focuses on analysis of the observational component conducted by Dr. Laurie
Padman (Oregon State University). The observational data set discussed here includes nearly-
continuous profile measurements of currents, temperature, salinity and turbulence at a fixed location.
Calibrations and data processing are described and observations are summarized. .
2
TABLE OF CONTENTS
1. OVERVIEW 4
2. MOORING MEASUREMENTS 4
MICROSTRUCTURE PROFILER MEASUREMENTS3 6.
4. ADCP MEASUREMENTS 9
APPENDIX: CALCULATION OF DISSIPATION RATES 12
LIST OF TABLES 17
LIST OF FIGURES 18
3
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
1. OVERVIEW
The study site was located around 74° 27.398N, 97° 15.788' W, in Barrow Strait in the
central Canadian Arctic Archipelago (Figure 1.1). The locations of various instrumented sites within
the camp itself are shown in Figure 1.2. Table 1 provides a summary of the Res95 instrumentation,
including those maintained by other investigators. The instruments discussed in detail in this report
are: temperature and salinity sensors mounted at various depths on a mooring line; a downward-
looking, 300 kHz, narrow-band acoustic doppler current profiler (ADCP) mounted just below the
ice surface; and a profiler (RSVP) measuring temperature, conductivity and velocity shear
microstructure. Figure 1.3 shows time lines for each of these instruments, depicting periods of good,
calibrated data. [Throughout this report, time is given in decimal day-of-year (where 00:00 UT on
January 1, 1995 corresponds to t=1.0).]
Figure 1.4 shows the position of the two hydroholes inside the main science hut. One hole
was used to mount the ADCP, the other for the RSVP, CTD and bottle casts. All depths are
referenced to the ocean-ice interface. In this region the bottom of the ice was very smooth,
consisting of undeformed, first-year, land-fast ice. Large rafts of multi-year, landfast ice were
observed to the northeast of the study site, as well as along the coast of Lowther Island (see Figure
1.5). Water depth at the main science hut was 152m, while depths at other instrumented sites varied
from 151 to 165 m.
A set of CD-ROMs have been generated containing raw and processed forms of the data
described in this report. File names in this report correspond to file names on the CDs.
2. MOORING MEASUREMENTS
Three Seabird SBE CTD sensors and eight Alpha-Omega miniature data recorder (MDR)
temperature sensors were installed on a 3/16" kevlar cable, which was moored to the ice and held
taut with a 50 lb. anchor weight; depths of the sensors are given in Table 2. The mooring was fully
deployed around 23:30 UT, April 26, 1995 (year day 116.9792) and recovered around 15:00 UT,
4
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
May 18, 1995 (year day 138.625). All of the moored sensors were set to sample at one minute
intervals. One thermistor (MDR-107) failed very early in the experiment.
The thermistors were calibrated in December 1994 in Oregon State University's large, slowly
drifting temperature bath (with a drift rate of about 2x 10-3 °C per minute) over the desired
temperature range (-2.5 to 2°C). A frequently-calibrated Seabird standard (SBE-544) is used to
provided absolute temperature. The Seacat (T, C) sensors (including SBE-544) were calibrated by
Seabird Electronics in March 1994.
In order to estimate noise levels for temperature (T) and conductivity (C), we examined the
power density spectra for each sensor. At high frequencies the spectra flatten out, which we attribute
to this frequency band being dominated by noise. Assuming that the spectral level in the noise region
represents white noise that extends from zero to the Nyquist frequency, we can obtain the rms noise
level. Table 3 provides estimates of the rms noise level for each of the thermistors, and Table 4
provides noise level estimates for both the conductivity cells and for the derived salinity. We expect
the true noise level for sensors of one type to be similar: the increase in nns noise level with depth
for T suggests that, even at high frequencies, true signal is responsible for much of the power spectral
density at greater depths where variations in T are more pronounced.
Two versions of the mooring temperature and salinity data have been retained. The first
version is the full calibrated data with a 1 minute sampling interval. The second version is a low-
pass-filtered (phase-preserving, net 8th-order Butterworth filter, with a 1 hour cutoff period) data set
which has been subsampled to a 1/2 hour sampling interval. Figures 2.1 and 2.2 show overlays of
selected mooring temperatures, and all salinity time series, respectively. Figure 2.3 shows a plot of
temperature as a function of depth and time. Figure 2.4 and Figure 2.5 show examples of raw,
filtered, and filtered/subsampled data sets for temperature and salinity, respectively. In both figures,
we plot the time series and spectra (in two different forms) for the raw, filtered, and
filtered/subsampled data in order to show how the processing affects the characteristics of the data
sets. The spectra in these figures were calculated with the PSD function in MatlabTM (which uses
Welch's averaged periodogram method; see Oppenheim and Schafer [ 1975] and Little and Shure
[1993]). We used 8192 Fourier coefficients for the unfiltered and filtered data, and 273 coefficients
for the filtered/subsampled data, these choices leading to essentially the same number of degrees of
freedom for the spectral averages for the three spectra. It can be seen from these figures that the low
frequency information in the unfiltered data is well-preserved in the filtered, subsampled data.
5
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Two of the MDR units on the mooring line also recorded pressure (see Table 2) and indicated
no measurable swing of the mooring line. Another sensor, operated by McGill University (G.
Ingram, P.I.), was placed on the seabed to measure tides and bottom water temperature. Figure 2.6
shows time series plot of those data.
3. MICROSTRUCTURE PROFILER MEASUREMENTS
Profiles of temperature, conductivity, and velocity shear were measured using the OSU Rapid
Sampling Vertical Profiler (RSVP). The RSVP, as configured for Res95, is very similar to the
version described by Robertson et al. [1995]. The instrument is designed to fall quickly and without
appreciable vibration through the water column. At the beginning of an RSVP profile measurement,
the profiler is at rest. The RSVP is then released and accelerates under gravity to a terminal velocity
of roughly 1.2-1.3 ms 1, which is determined by buoyancy elements and drag brushes. The profiler is
arrested at a predetermined depth determined by the length of instrument cable made available.
Figure 3.1 shows an example of a typical drop speed profile.
The RSVP sampling strategy was to alternate between profiling frequently for roughly 25
hours (generally to a depth of about 125 m), then pausing for about 23 hours. This strategy was
designed within manpower constraints to provide frequent data through two M2 tidal periods every
two days through a complete spring/neap tidal cycle. Each profile generated a data set identified by a
profile i.d. (also referred to as "drop number"). Each 25-hour collection of profiles is identified as a
"batch". Preliminary tests were carried out between April 25 and April 30; the data from this period
have been dubbed'batch 0'. Batch 1 through 9 denote sets of profiles collected between April 30
(year day 120) and May 17 (year day 137), spanning a total period of 18 days, or a little more than
one spring-neap cycle (see Figure 2.6). The sampling frequency was usually set to 256 Hz and the
terminal fall speed of the probe was usually about 1.2 - 1.3 ms 1, which led to a typical sampling
interval of about 5 mm (although none of the sensors are actually able to resolve down to this scale,
i.e. all data are oversampled). The start time and date for each drop, along with other related
information, is provided in a data file called `dropsum.tab'.
As a part of the RSVP calibration procedure, each profile data set was plotted on a computer
screen and examined visually to identify obvious problems or unusual circumstances; a 'quality code'
was ascribed to each profile, denoting the apparent integrity of the recorded data channels. In
6
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
particular, RSVP data files were flagged as 'bad' (data quality code=2) under the following
circumstances: data file was missing or empty; data file was very short; sampling frequency was less
than 256 Hz; pressure (and therefore depth) did not increase during data collection, so the file did not
represent a 'drop'; the temperature channel was clearly bad. Table 5 describes the code values and
their interpretation. The quality codes for all the drop files are presented in Table 6; Table 7 presents
a data summary of the RSVP batches. In addition, a comment file ('DropNotes.txt') was also
developed which describes an assessment of the drop file data sets.
In total, 1231 drop data files were generated. Of these, 1064 appear to have good temperature
and conductivity profiles; 995 of these data sets occur in batches 1-9. In all of the drop files except
one, data from shear probe S2 (the second of the two shear probes on the instrument) werehighly
corrupted, possibly due to a grounding problem with the S2 data channel. However, Si (first shear
probe) gave good results in almost all the drop profiles. In all, 1046 drop profiles have good
temperature, conductivity and shear data (see Tables 6 and 7).
Two separate forms of processed data files are generated for each valid RSVP drop file. One
consists of 8-point (i.e., 1/32 second) averages of depth, temperature, conductivity, and shear; the 8-
point data retain most of the frequency response available in the thermistor and shear sensors. The
second type of processed data are 256-point (i.e. one second, or roughly 1.2m) block averages of
depth, temperature, conductivity, salinity, and dissipation rate. For data channels with 'bad' values,
the associated measurements in the processed data sets are 'flagged' by setting them to a standard
value of 999.99.
The RSVP temperature and conductivity laboratory calibrations are less accurate and stable
than calibrations for the moored Seabird CTDs and MDR units. Consequently, in order to improve
the absolute accuracy of the RSVP measurements, we first compared mean RSVP and mooring
temperature profiles over each batch. The results showed that the RSVP temperatures based on
laboratory calibrations were systematically colder than the mooring temperatures. We examined the
temperature differences in a variety of ways, including histograms and scatterplots as a function of
depth and of mooring temperature. Based on these comparisons, we have added a constant offset of
+0.007°C to the RSVP temperatures. This offset is incorporated in the calibrated data files (which
are generated by the calibration program, `newcalibrat.f'). Figure 3.2 shows a typical comparison of
the batch-averaged temperature profile determined from the mooring, uncorrected RSVP
7
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
temperatures, and corrected RSVP temperatures. The RSVP temperature correction clearly improves
the comparison against the mooring.
We have also compared batch-averaged conductivity profiles from the RSVP and the moored
CTDs. The RSVP conductivities are consistently higher than the moored values. The differences at
7m and 30m depth are fairly well-represented by a constant offset of -0.24 mS cm -1 (equivalently,
mmho.cm"1). The differences at 15m are somewhat higher, but the CTD sensor at this depth is in the
halocline, and the differences may be attributed to a depth offset of only 2m between the moored
CTD sensor and the RSVP pressure measurements. Consequently, we have incorporated a uniform
correction of -0.24 mS cm1 to the RSVP conductivities. Figure 3.3 shows a typical comparison of
the batch-averaged conductivities from the moored CTDs and corrected and uncorrected RSVP
profiles. Again, the RSVP correction clearly improves the comparison against the mooring data.
It is well-known that the response time of the RSVP conductivity cell is somewhat slower
than the response time of the RSVP thermistor, owing in large part to the flushing time and the
thermal inertia of the cell (c.f. Lueck and Picklo [1990]; Morison et al. [1994]). This effect leads to
a time delay between temperature and conductivity sampling of the same water depth, which can
lead to significant errors in salinity calculations. This problem was noted during recent studies in the
Antarctic (e.g., Robertson et al. [1995]), where temperature variations generally play a much greater
role than salinity in setting conductivity. However, in the present data set, salinity variations play a
dominant role in setting conductivity: temperature effects are almost negligible due to the small
overall change in T throughout the water column. After careful examination of the RSVP
temperature and conductivity data, we found it unnecessary to compensate for any slight time delays
between the sensors. Salinities and densities were then derived using the standard formulas.
During a period of roughly one hour on May 11 (day 131), a cross-calibration test was
carried out using the RSVP profiler, mooring sensors, and a Seabird CTD from McGill University
(G. Ingram, pers. comm.). The CTD profile began at 20:14 UT; one RSVP profile began at 20:44
and another began at 21:09. Figure 3.4 (a) shows a comparison of temperature profiles from the
McGill CTD and the two RSVP profiles; the minimum and maximum temperatures observed
between 20:14 and 21:09 at each thermistor on the mooring are also shown. There is clearly some
variability among all three of the continuous profiles, but most of this is likely due to internal wave
activity and tidal advection of horizontal property gradients. Figure 3.4 (b) shows a comparison of
salinities from the same instrumentation. The results suggest there is still a systematic, finite offset
8
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
of roughly 0.04 to 0.06 psu between the McGill salinity and the RSVP and mooring salinity. (A
fixed depth offset of about 10 in can also account for the differences in the deep portion of the
salinity profile, but then the salinity differences in the upper portion of the water column become
unrealistic). At this stage we do not attempt to correct for this difference, but we note that the offset
appears to be nearly independent of depth.
The temperature and conductivity measurements are essentially independent of RSVP fall
speed of the RSVP, however the shear measurements and inferred dissipation rates are not. In
practice, we use the fall speed to determine the valid depth range for shear and dissipation estimates
as follows: we define the first valid depth is the first depth at which the profiler fall speed is greater
than 1.0 ms-1; the last valid depth is the next depth at which the profiler speed is greater than 1.5 ms -1
or less than 0.8 ms-1. Figure 3.5 shows the valid depth range for shear and dissipation rateestimates
for each RSVP profile, organized by batch number.
Examples of shear time series and wavenumber power spectra are shown in Figures 3.6 and
3.7. Under the assumption of a frozen turbulence field (Taylor's hypothesis), we can relate the cyclic
frequency, f, to a scalar wavenumber in the (vertical) profiling direction, k, through the fall speed, w:
kZ =2af
(1)W
Since the fall speed is fairly constant (w-1.25ms 1) for the depths of interest, the relationship
between kZ and f is effectively linear.
Values of the energy dissipation rate, e, are estimated from the shear spectra using an iterative
integration technique. The details of this method, as applied to the RSVP data from Res95, are
presented in the Appendix.
Summary plots of the RSVP data for the nine batches are shown in Figures 3.8 - 3.16. The
plotted measurements include temperature (T), salinity (S), buoyancy frequency (N) and energy
dissipation rate (E).
4. ADCP MEASUREMENTS
A 317 kHz RDI narrow-band ADCP operating in high-power mode (AC power provided
externally) was installed in a downward-looking orientation in a hydrohole at the SW corner of the
9
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
main science hut (Figure 1.4). The transducers were set in a convex pattern with a 30° beam angle,
and were mounted in a square sea chest, with the four beams directed along the diagonals of the
chest (see Figure 1.4). Transducer beam 3 (see RD Instruments [ 1991 ]) was determined to be
directed 3 degrees North of Gourdeau Point on Lowther Island, so the long axis of the science hut
was oriented 48 degrees North of Gourdeau Point. The depth of the transducer head. is 1.8m below
the mean water surface, and recorded depths are corrected to the surface accordingly. ADCP data
were logged both internally and on the hard drive of an IBM-compatible computer. Acoustic
backscatter levels were also recorded by the ADCP, but have not yet been examined in detail.
However, it is known that backscatter data do provide a useful alternative view of the vertical motion
associated with higher-frequency internal waves in the main pycnocline.
A timing problem occurred with the instrument during the experiment, which regularly shut
down data logging at midnight UT every day. This led to the generation of short data gaps, and a
total of 45 ADCP data files being generated. Table 8 summarizes the ADCP times and instrument
settings for these 45 data files. The first available data starts at 16:23 UT, April 25, 1995 (year-day
115.6826) and the last available record corresponds to 03:55 UT, May 18 (year-day 138.1632). Ping
repetition period was fixed at 0.4 seconds; the number of pings averaged for velocity estimates was
varied between 140 and 300; pulse width (and hence bin width) was varied between 2m and4m, as
specified in the setup software. Correction to the depth bins was later made using estimates of the
speed of sound profile derived from RSVP data. Figure 4.1 shows the average speed of sound
profile from all valid RSVP profiles collected during the experimental period. Sound speed over the
range of valid velocity data varied from about 1436.5 ms 1 to 1441 ms-1. We have chosen a mean
sound speed of 1439.2 ms-1 to relate the binned ADCP data to depths. Errors in the depths
associated with ignoring sound speed profile variation is limited to less than 4 cm. Good ADCP
profile data were retrieved consistently to at least 120 in. The mean sound speed at the transducer
head was about 1436.5 ms-1; this value is used in the conversion of Doppler-shifted frequency
estimates to velocity estimates [RD Instruments, 1991 ].
The ADCP initially records data from all four transducer heads. We took these data and
determined velocity components in beam coordinates, as defined by RD Instruments. The velocity
component along the beam 1 - beam 2 axis (referred to as v12) is within a few degrees of being
aligned with the north-south direction, and the component along the beam 3 - beam4 direction (v34)
is very nearly aligned west-east. We therefore associate the east-west velocity, v, , as vX = - V34
10
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
(since beam 3 points nearly west) and the north-south velocity, vy, as Vy =V12- Vertical velocity, vz,
is generally low and comparable in magnitude to the error velocity estimate, verr. However, there are
several short periods where vZ is much larger than ve1l, and thus appears to represent a true vertical
velocity. Figs. 4.2 - 4.5 show examples of the ADCP velocity components (vs, vy, vz, and veer,
respectively) at four selected depths.
The various velocity files were low-pass filtered (using a phase-preserving, net 8"'-order low-
pass Butterworth filter, with 1 h cutoff period), subsampled to half-hourly intervals, and re-
formatted. Tidal current analysis was then carried out on the entire available time series using the
algorithms of Foreman [ 1993]. The length of the time series allowed for 18 different tidal
constituents to be evaluated. Table 9, 10, 11 and 12 provide the tidal analysis results over the water
column resolved by the ADCP (5.5 in to 114.2 in, at roughly 4 in intervals) for the K1, 01, M2 and
S2 constituents, respectively; Tables 13, 14, 15, and 16 present the analysis results for all 18
constituents at 9.3, 28.0, 50.5, and 99.2 in depth, respectively. These analyses include the mean
current, shown in the Tables as Z0. We also used the Foreman algorithms to output the time series
of analyzed tidal currents for the measurement period with a one-hour time interval. Figures 4.6, 4.7,
4.8 and 4.9 show comparisons of the low-passed horizontal velocity components and the velocities
reconstructed from the tidal analysis at 9.3, 28.0, 50.5 and 99.2 m depth, respectively.
Acknowledgments: We wish to thank the staff of the Polar Continental Shelf Project at Resolute for
providing logistical support and Walt Waldorf, Miles McPhee, Guy Millette, Paul Peltola, and Zeus
Kerravala for providing technical support. Greta Reynolds and Rick Guritz of the Alaska SAR
Facility, University of Alaska Fairbanks, provided the SAR image data. This project was funded by
the National Science Foundation (DPP-9224303, and OPP-9530916).
11
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
APPENDIX: CALCULATION OF DISSIPATION RATES
For homogeneous, isotropic turbulence, the energy dissipation rate, c, is related to the integral
of the vertical shear spectrum, according to
00
2v f cp(kk )dkk
0
(Al)
where v is the kinematic viscosity, cp(kk) is the power spectrum of measured turbulent shear, au'/az
(where z is in the vertical [profiling] direction, kZ is a wavenumber component in the z direction, and
u' is the turbulent velocity component in a fixed horizontal direction, (i.e., tangential to z); see also
Tennekes and Lumley [1972]). In practice, one is usually limited to evaluation of the spectrum over
a finite range of wavenumbers, due to a number of constraints (e.g. finite sampling, noise levels,
anisotropic behavior at low, buoyancy-influenced, wavenumbers). We can rewrite (Al) as
Er(k',k2) (A2)
where
g(k,,k2)
k2
En(k,,k2,£) =15
v f (p (kz)dkk
k,
(A3)
is a partial estimate of t, and
k2
f (p (kk)dkk
k,g(k,,k2,£) CIO
(A4)
f sp (kk )dkk
0
represents the fraction of the total variance of the turbulent shear captured within the spectral band
[kt,k2]. In other words, g represents a correction factor for estimation of e from fr,, (note that, since
is a function of F-, so is g).
For isotropic turbulence, the theoretical shear spectrum has a universal form, sometimes
referred to as the Nasmyth spectrum, given by
4,
12
Oceanographic Measurements in Resolute 1995
T, = kr2(EV5)ll4G2
where
ks =(EV-3)114
Crawford and Padman (Oregon State U.)
(A5)
(A6)
is the characteristic (Kolmogorov) wavenumber and G2 is a nondimensional shape function. Oakey
[1982] provides tabulated values of G2 (derived from the data of Nasmyth [1970]) at specific values
of k Iks, where k = k/2it is the cyclic wavenumber; in Table Al, we re-write those data values in the
more standard notation, G2 (k / k,) = G2 (k l k,) / 27r. The spectrum tot is peaked, with the peak
occurring at about 0.lks. As E increases, the spectral energy levels increase and the peak shifts to
higher wavenumbers.
Following equations Al-A6, we define two more functions: a theoretical partial estimate of
dissipation rate (based on Nasmyth spectra), en,, given by
k2
E,P(k,,k2,E) = 21
v f cp,(k,)dkk (A7)
k,
and the associated theoretical fractional variance function, gt, given by
k2
f cpt(k,)dkk
k, Etngt(k,,k2,E)=00
f tp,(k,)dkZ
0
r -
(A8)
Figure A.1 shows plots of the cumulative integration of the tpt , normalized to the total
variance of the spectrum, for a variety of values of E. Values of E that are most commonly observed
in the stratified ocean are in the range10"9<£<10"5 m2s 3, the lower limit being due to noise levels of
shear probes and the upper limit being set by the spatial response of shear probes. For this range of s,
most of the contribution to the total variance in the shear spectrum occurs at wavenumbers between
about 10 mt and 400 m 1. Indeed, for e - 10-9 - 10-8 m2s 3, most of the energy appears at
wavenumbers less than 100 m-1. Figure A.2 shows examples of gt , as a function of e, obtained by
integrating (pt over two different wavenumber bands: [k1,k2] = [12 m-' , 320 m-' ] and
13
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
[k1,k2] _ [12 m t, 80 m' ]; Figure A.3 shows gt as a function of a , for the same wavenumber
bands. These latter curves allow us to recover E from a particular measure of Etr and (k1, k2) using
(A.2).
We assume the measured spectrum, rp,, is well-represented by
Y'm = T, +T., (A9)
where con is the noise spectrum, over a range of wavenumbers associated with the inertial subrange
and down to viscous dissipation scales. One can therefore also calculate an observationally-
determined partial estimate of E, denoted by E,np, from
15 k2 15Emp(k,,k21E) = 2 V f (m(kz)dkz = v
k,
k2 k2
f t'p, (kz )dkz + f cpn (kz )dkz
k, k,
(A 10)
In regions with high energy in the shear signal (e.g., Figure 3.6), the peak location and the shape of
the measured shear spectra is well-represented by the Nasmyth spectrum (cpm - (pt). In regions with
low shear energy (e.g., Figures 3.6 and 3.7), the peak is harder to pick out of the background noise
and there is a lot of noise at the higher end of the spectrum which is not related to the theoretical
spectrum.
As mentioned in Section 3, the profiler fall speed is generally very steady at about
w=1.25 m s t, so the vertical wavenumber kZ and frequency f are linearly through (1). The measured
shear spectra suggest that a lower bound off1=2 Hz (k1 - 12 m-1) is reasonable and allows us to get a
spatial (vertical) resolution of as small as 1.25 m; for conditions of moderate to high turbulence,
noise in the data does not contribute significantly to the spectra below frequencies of about 64 Hz
(k2.-320 m1), while for low turbulence conditions the noise can play a significant part in the variance
and therefore may lead to overestimates of the true shear variance and, hence, E.
While we do not have a detailed model or measurements of the noise spectrum, we seek to
minimize the contribution of spectral noise to our estimates of E (thereby reducing the noise floor of
those estimates) while at the same time preserving good estimates of E; we also wish to eliminate
shear values that arise through sensor impact with bugs, ice crystals and other particles in the water
column, which lead to data spikes. In order to do so, we have adopted the following procedure.
First, the shear data are divided into 256-point (1 second) blocks. For each block, despiking is
performed by identifying shear values greater than three standard deviations from the mean shear
value of that block and setting those values to zero. This despiking process is carried out twice. The
14
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
number of points that are rejected by the despiking algorithm is rarely a significant fraction of the
original block of 256 points, hence no correction is made to the estimated variance to compensate for
rejected points.
An adaptive integration scheme is then applied to each valid block. First, the measured shear
(wavenumber) power spectrum, cpm, for a 256 point (1 second) block is determined using a FFT, the
mean fall speed over the block period, and from (1). The lower bound on spectral integration is
fixed at f1=2 Hz, while the upper bound is first initialized to f2=16 Hz; the equivalent bounds on the
wavenumbers k1 and k2 are also determined (1). The algorithm calculates a partial estimate of
dissipation rate, £,,,p(kl, k2) from (A10), then estimates gm(kl, k2, E,,,p) and E by assuming (Qm"'O and
spline-interpolating Emp to predicted values of F -,p inferred from (A7). If the estimated value of gm is
less than a minimum threshold (taken as g, = 0.75), then the estimate of E is rejected and the upper
bound of integration is increased incrementally by 4 Hz. The procedure is then repeated until the
algorithm detects that at least 75% of the predicted shear variance is captured within the bounds of
integration (i.e. gm>_ ge). The associated dissipation rate estimate is then accepted (N.B., a maximum
value of f2 = 64 Hz was used, although the algorithm always converged to an acceptable limit before
this limit was reached). Based on the distributions of e that are found in the least energetically-
mixing regions, we determine that the noise floor for E estimates is about 2x 10-9 m2s"3.
Figure A.4 shows an example of a profile of E for a set of measurements with both high and
low shear variance regions. Three different estimates of E are displayed, all three of which use the
same, fixed low frequency for integration, f, =2 Hz; the first method uses f2=16 Hz, the second uses
f2=64 Hz, and the third uses our adaptive scheme for f2. All three methods correct for the finite
spectral bandwidth using an estimate of g(kl, k2, E), where k, and k2 are computed fromf1 andf2 from
(1) using the average fall speed w over each 256 point (1 second) vertical bin. It can be seen that, for
the high shear regions, the results from the adaptive scheme closely match those derived from the
f2=64 Hz case; for the low shear regions the adaptive scheme estimates of E match the f2=16 Hz case
and are generally lower than estimates based onf2=64 Hz (which would include more noise
contribution) as expected. Figure A.5 shows another energy dissipation profile determined from the
adaptive scheme, along with the associated value of f2 at each depth.
15
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
REFERENCES
Foreman, M.G.G., 1993. Manual for Tidal Currents Analysis and Prediction. Pacific MarineScience Report 78-6. Institute of Ocean Sciences, Sidney, B.C. Canada. 66pp.
Little, J.N., and L. Shure, 1993. Signal Processing Toolbox User's Guide. The Mathworks, Inc.,Natick, Mass.
Lueck, R.G., and J. J. Picklo, 1990. Thermal inertia of conductivity cells: Observations with a Sea-Bird cell. J. Atmos. Oceanic Technol., 7, 741-755.
Morison, J., R. Andersen, N. Larson, E. D'Asaro, and T. Boyd, 1994. The correction for thermal-lageffects in Sea-Bird CTD data. J. Atmos. Oceanic Technol., 11, 1151-1164.
Nasmyth, P., 1970. Oceanic turbulence. Ph.D. thesis, Institute of Oceanography, University ofBritish Columbia, 69 pp.
Oakey, N., 1982. Determination of the rate of dissipation of turbulent energy from simultaneoustemperature and velocity shear microstructure measurements. J. Phys. Oceanogr., 12, 256-271.
Oppenheim, A.V., and R.W. Schafer, 1975. Digital Signal Processing. Prentice-Hall.RD Instruments, 1991. Self-contained Acoustic Doppler Current Profiler (SC-ADCP) TechnicalManual. RD Instruments, San Diego.
Robertson, R., L. Padman, and M. D. Levine, 1995. Fine structure, microstructure, and verticalmixing processes in the upper ocean in the western Weddell Sea. J. Geophys. Res., 100 (C9),18,517-18,535.
Tennekes, H., and J. L. Lumley, 1972. A First Course in Turbulence. The MIT Press, Cambridge,Mass., 300 pp.
16
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
LIST OF TABLES
Table 1. Summary of oceanographic instrumentation deployed during Resolute 95.
Table 2. Moored instrument summary. Variables include temperature (T), conductivity (C), andpressure (P).
Table 3. Moored thermistor noise levels (inferred from observed temperature spectra).
Table 4. Moored conductivity and salinity noise levels (inferred from observed spectra).
Table 5. RSVP drop file quality codes (following the format developed by R. Robertson).
Table 6. Quality codes for RSVP profiles. The first column in each row gives the profile W.number for the first profile of each group of twenty profiles; the next twenty columns (given ascomma-separated values) indicate the quality code for profile number and the next nineteenprofiles in sequential order (thus, for the first row above, 0001 refers to RSVP profile # 0001,and the following 20 comma-separated values indicate the quality code for RSVP profiles #0001-0020, respectively. See Table 5 for interpretation of the code values.)
Table 7. RSVP batch drop summary.
Table 8. Summary of ADCP settings.
Table 9. Tidal analysis results for K1 tidal constituent, from 5m to 115m depth. Angle ofinclination denotes the clockwise rotation of the major axis relative to east. Positive values of theminor axis indicate counterclockwise rotation of the tidal component; negative values indicateclockwise rotation.
Table 10. Same as Table 9, but for 01 tidal constituent.
Table 11. Same as Table 9, but for M2 tidal constituent.
Table 12. Same as Table 9, but for S2 tidal constituent.
Table 13. Entire 18-component tidal analysis for 9.3 in depth bin.
Table 14. Same as Table 13, but for 28.0 in depth bin.
Table 15. Same as Table 13, but for 50.5 in depth bin.
Table 16. Same as Table 13, but for 99.2 in depth bin.
Table A-1. Discrete values of the universal shape function for the shear spectrum (after Oakey[ 1982] and Nasmyth [ 1970]). The data have been re-written from Table Al in Oakey [ 1982] in termsof wavenumber instead of cyclic wavenumber.
17
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
LIST OF FIGURES
Figure 1.1a: Map of the Canadian Arctic Archipelago. The Res95 experimental site is in BarrowStrait, in the center of the archipelago. A finer-scale view of the region immediately surrounding thecamp is shown in Figure 1.1b (following page).
Figure 1.1b: Map of the central Barrow Strait region, showing more detail in the area indicated by abox in Figure 1.la. Bathymetric contours in (b) are given in meters. The Res95 camp is locatedaround 74° 27.398' N, 97° 15.788'W, southeast of Lowther Island.
Figure 1.2: Locations of primary instrumented sites at the Res95 camp.
Figure 1.3: Time lines of good, calibrated data for each of the instrument packages discussed in thisreport.
Figure 1.4: A schematic showing the location of the two hydroholesinside the main science tent
and the orientation of the transducers.
Figure 1.5: A portion of a synthetic aperture radar (SAR) image, obtained by the ERS-1 satellite onMay 2, 1995 (year day 122) showing the study site. The image (which has been rotated so that thetop of the page is in the northward direction) consists of 8 bit pixels, corresponding to uncalibratedbackscattered intensity. Pixel resolution is roughly 100 m by 100 m. Lowther Island is clearlyidentifiable. The ice camp was located on land-fast first-year ice; the medium gray masses along the
coast of Lowther Island and to the northeast of the study site represent land-fast, multi-year ice (SARimage data provided by G. Reynolds, Alaska SAR Facility, University of Alaska Fairbanks [data take
i.d. EI/S/19860.01; image i.d. 183735200]).
Figure 2.1: Moored temperature time series from selected depths (125, 75, 25, 7 m). Samplinginterval is one minute.
Figure 2.2: Moored salinity time series from the three CTDs (30, 15, 7 m). Sampling interval is
one minute.
Figure 2.3: Mooring temperature as a function of depth and time.
Figure 2.4: Temperature data from MDR 106 (50 m depth). Top panel shows the entiretemperature time series. Middle panel displays the log-log plots of the power spectral density, PSD,of the raw time series (blue), the low-pass-filtered time series (green), and the low-pass-filtered,subsampled time series (red). Bottom panel shows same data as the middle panel, plotted here as the
frequency times the PSD on a log-linear scale. Filter cutoff period is 1 h; raw sampling interval is 1
min.; time interval for subsampled data is 30 min. See text for more details on the filtering,subsampling, and spectral estimation.
Figure 2.5: Salinity data from SBE 40 (30 m depth). Top panel shows the entire salinity timeseries. Middle panel displays the log-log plots of the power spectral density, PSD, of the raw timeseries (blue), the low-pass-filtered time series (green), and the low-pass-filtered, subsampled time
18
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
series (red). Bottom panel shows same data as the middle panel, plotted here as the frequency timesthe PSD on a log-linear scale. Filter cutoff period is 1 h; raw sampling interval is 1 min.; timeinterval for subsampled data is 30 min. See text for more details on the filtering, subsampling, andspectral estimation.
Figure 2.6: Time series of measurements from the McGill sensor mounted on the seabed: (a) waterlevel (height of water above the sensor); (b) bottom water temperature.
Figure 3.1: Fall speed profile for drop number 180. The profiler is seen to quickly accelerate to itsterminal velocity of about -1.25 ms-t (a negative value here implies descent) and to continue to fall atabout that speed throughout the water column. The profiler is quickly arrested at the end of theprofile near 110 m depth.
Figure 3.2: Sample comparison of time-averaged temperature profiles from the mooring (opencircles), the uncorrected RSVP data (dashed line) and the corrected RSVP data (solid line),evaluated over the entire period of batch 2 (day 122.6347 to 123.6669). The RSVP averages arederived from the 256-point `block' averages and have been bin-averaged in 1 m depth bins.
Figure 3.3: Sample comparison of time-averaged conductivity data from the mooring (open circles),the uncorrected RSVP data (dashed line) and the corrected RSVP data (solid line), evaluated overthe entire period of batch 2 (day 122.6347 to 123.6669). The RSVP averages are derived from the256-point `block' averages and have been bin-averaged in 1 m bins.
Figure 3.4a: Comparison of temperature data during cross-calibrationrun on May 11 (year day131). The dotted line is from the McGill CTD at 2014 h; the solid line is from the RSVP profiler at2044 h; the dashed line is from the RSVP at 2109; open circles identify the minimum and maximumvalues observed at the mooring between 2014 h and 2109 h.
Figure 3.4b: Comparison of salinity data during cross-calibration run on May 11 (year day 131).The dotted line is from the McGill CTD at 2014 h; the solid line is from the RSVP profiler at 2044h; the dashed line is from the RSVP at 2109; open circles identify the minimum and maximumvalues observed at the mooring between 2014 h and 2109 h. The results suggest there is a nearlyuniform offset between the McGill salinity and the RSVP mooring salinity, corresponding to roughly0.04 to 0.09 psu. No attempt has been made at this stage to correct for this difference.
Figure 3.5a: Depth range of valid RSVP data vs. RSVP drop number for Batches 0 and 1.
Figure 3.5b: Depth range of valid RSVP data vs. RSVP drop number for Batches 2 and 3.
Figure 3.5c: Depth range of valid RSVP data vs. RSVP drop number for Batches 4 and 5.
Figure 3.5d: Depth range of valid RSVP data vs. RSVP drop number for Batches 6 and 7.
Figure 3.5e: Depth range of valid RSVP data vs. RSVP drop number for Batches 8 and 9.
19
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Figure 3.6: Shear time series and frequency spectra for RSVP Drop 653. (a) Time series of shearfrom shear channel S 1, with times plotted relative to the beginning of data collection for that profile.Two short, 256-point (1 second) data segments are selected, representing high and low regions ofshear variance (labeled A and B, respectively). Drop speed was about 1.15 ms-1 and very stable overmost of the profile; A corresponds to about 32 m and B to 87 m depth. (b) Wavenumber powerspectra for time series A (thick line) and B (thin line), plotted on a log-log scale as kZ toM (ks) vs. kZ.No spectral averaging is performed here; note that this is not an energy-preserving plot, but doesallow visualization over a very broad dynamic range. Dashed lines show theoretical Nasmyth spectrafor different orders of magnitude of the dissipation rate, ranging from E = 10"9 to 10-5 m2s 3. Atwavelengths greater than about 320 m-1 (denoted by a vertical line; f -- 64 Hz), the spectra drop offsharply due to the frequency characteristics of the shear probe and data collection scheme. In the lowdissipation measurements, much of the energy greater than 80 m-1 is probably due to electronic noiseand profiler motion and vibrations.
Figure 3.7: Similar to Figure 3.6, but for RSVP Drop 1184; data segments A and.B correspond to10 m and 93 m depth, respectively; drop speed was steady at about 1.20 ms-1.
Figure 3.8: Stack plot summary of RSVP profile data for batch 1. Panels represent (from top tobottom), temperature (T, in °C), salinity (S, in psu), buoyancy frequency (N, in cycles/hour), anddissipation rate (as loglo[E], with E in m2s"3).
Figure 3.9: Same as Figure 3.8, for batch 2.
Figure 3.10: Same as Figure 3.8, for batch 3.
Figure 3.11: Same as Figure 3.8, for batch 4.
Figure 3.12: Same as Figure 3.8, for batch 5.
Figure 3.13: Same as Figure 3.8, for batch 6.
Figure 3.14: Same as Figure 3.8, for batch 7.
Figure 3.15: Same as Figure 3.8, for batch 8.
Figure 3.16: Same as Figure 3.8, for batch 9.
Figure 4.1: Average sound speed profile (solid line), as determined from the RSVP data. Thedashed lines represent plus or minus one standard deviation.
Figure 4.2: Time series of raw, ADCP-derived measurements of eastward (v,,) velocity at specifieddepths: (a) 9.3 m; (b) 50.5 m; (c) 99.2 m. The reduction in high-frequency variability between day122 and day 127 is primarily a consequence of a longer pulse width and an increased number ofsamples per ensemble (see Table 8).
Figure 4.3: Same as for Figure 4.2, but for northward (vy) velocity.
20
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Figure 4.4: Same as for Figure 4.2, but for vertical (v2) velocity.
Figure 4.5: Same as for Figure 4.2, but for the error velocity (VeTC).
Figure 4.6: Comparison of low-frequency velocities (solid lines) and reconstructed velocities(dashed lines) from tidal analysis at 9.3 m depth: (a) eastward component; (b) northward component.Time interval shown for the plotted data is 1 hour; time range is limited to a 5 day section for ease ofcomparison.
Figure 4.7: Same as for Figure 4.6, but for 28 m depth.
Figure 4.8: Same as for Figure 4.6, but for 50.5 m depth.
Figure 4.9: Same as for Figure 4.6, but for 99.2 m depth.
Figure A.1: Cumulative integration of Nasmyth shear spectra, qpt, normalized to the total shearvariance, for several values of dissipation rate, E. Integrations were carried out numerically, based onvalues of G2(k/k,) given by Oakey (1982). For the range of £ typically found in the ocean(10-1<F<10-5 m2s-3), most of the spectral energy occurs at wavenumbers between about 12 mt and320 m-1; for £=10-9-10-8 m2s-3, most of the energy occurs between 12 in-' and 80 m 1.
Figure A.2: Estimates of gt, the fraction of the variance in the Nasmyth shear spectrum, captured ina fixed spectral wavenumber band [k1i k2], as a function of dissipation rate, E. Two differentwavenumber bands are shown: [k1, k2] = [12 m 1, 80 m f] and [k1, k2] = [12 m1, 320 m"1].
Figure A.3: Estimates of gt, the fraction of the variance in the Nasmyth shear spectrum, captured ina fixed spectral wavenumber band [k1, k2], as a function of the partial estimate, -tp. Two differentwavenumber bands are shown: [k1, k2] = [12 m 1, 80 in-] and [k1, k2] = [12 m-' 320 m-']. Ahorizontal line denotes the minimum threshold of gt = 0.75 required for determining observationalestimates of £ from integrations of observed shear spectra (see Appendix).
Figure A.4: Comparison of energy dissipation profile estimates for RSVP drop number 1184 forthree algorithms with different high-frequency cutoff values: f2 = 16 Hz (thin solid line), f2 = 64 Hz(dashed line), and a variable f2 (from the adaptive method; thick solid line). All three methods usethe same low-frequency cutoff, fl = 2 Hz, and make corrections for energy not included in thespectral range of integration (see Appendix).
Figure A.5: (a) Dissipation profile for RSVP drop number 1184, obtained using the adaptivemethod; (b) associated high frequency cutoff value, f2, used by the method. The minimum thresholdvalue of f2 = 16 Hz is clearly identified. When the energy levels in the shear spectra are high, thealgorithm integrates to higher frequencies (wavenumbers) to get a better estimate of the shearvariance.
21
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Instruments Location Sample Interval Principal Investigator300 kHz Narrow-Band
ADCPMain Science Hut 1 min x (2-4) m Padman (OSU)
600 kHz Narrow-BandADCP
Marsden ADCPIgloo
1 min x 1 m Marsden (RMC)
600 kHz Broad-BandADCP
McGill ADCP Igloo 10 s x I m Ingram (McGill)
RSVP MicrostructureProfiler
Main Science Hut 15 min for 25 h,every 48 h (see text)
Padman (OSU)
Temperature /Conductivity Mooring
Padman Mooring 1 min Padman (OSU)
Turbulence Frame McPhee Shelter 1 s McPhee/Padman
S4 Current Meters S4 East andS4 West
5 min Ingram (McGill)
Aanderaa T-C recorders Main Science Hut 1 min In ram (McGill)Aanderaa Tide Gauge McGill ADCP tent 30 min In ram (McGill)
Chemistry, radiation, andice
Biology Camp variable Cota (Old Dominion)
Table 1. Summary of oceanographic instrumentation deployed during Resolute 95.
22
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Depth belowice (m)
Sensor ID Variables
2 MDR-103 T7 SBE-43 T,C10 MDR-112 T15 SBE-41 T,C20 MDR-109 T25 MDR-116 P,T
30 SBE-40 T,C50 MDR-106 T75 MDR-101 T100 MDR-107 (did not work)125 MDR-100 P,T
130 50 lb. lead weight N/A
Table 2. Moored instrument summary. Variables include temperature (7),conductivity (C), and pressure (P).
Sensor ID SensorDepth
Spectral Noise Level(oC2-hr)
Rms Noise Level (°C)
MDR-103 2 1 x 10-7 2 x 10-3
SBE-43 7 6 x 10-8 1 x 10-3
MDR-112 10 2 x 10-7 3 x 10-3
SBE-41 15 2 x 10-7 3 x 10-3
MDR-109 20 2 x 10-7 3 x 10-3
MDR-116 25 2 x 10-7 3 x 10-3
SBE-40 30 4 x 10-7 4 x 10-3
MDR-106 50 4 x 10-7 4 x 10-3
MDR-101 75 8 x 10-7 5 x 10-3
MDR-107 100 (did not work) (did not work)
MDR-100 125 6 x 10-7 4 x 10-3
Table 3. Moored thermistor noise levels (inferred from observedtemperature spectra).
23
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Sensor ID Conductivity Salinity
Spectral Noise Level([mS/cm]2hr)
Rms NoiseLevel (mS/cm)
Spectral Noise Level([ su]2hr)
Rms NoiseLevel (psu)
SBE-43 1 x 10-6 6 x 10-3 2 x 10-6 8 x 10-3
SBE-41 1 x 10-6 6 x 10-3 2 x 10-6 8 x 10-3
SBE-40 2 x 10-7 3 x 10-3 1 x 10-6 6 x 10-3
Table 4. Moored conductivity and salinity noise levels (inferred from observed spectra).
RSVP DropFile Quality
Code
Description
0 file not evaluated (temporary status)1 all data channels good
2 bad drop file3 C (conductivity) channel bad4 S 1 (shear) channel bad
5 S2 (shear) channel bad
6 S 1 and S2 channels bad
7 C, Si and S2 channels bad
Table 5. RSVP drop file quality codes (following the format developed by R. Robertson).
24
Oceanographic Measurements in Resolute 1995
Profile Quality CodesI.D. (20 consecutive profiles)
0001: 2,2,2,2,2,2,2,6,6,2,2,2,2,2,2,2,2,2,2,2,0021: 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,5,2,0041: 2,2,2,2,6,2,2,6,2,2,2,2,2,2,2,2,2,2,2,2,0061: 4,2,4,4,4,4,6,2,4,6,2,2,2,2,2,4,4,2,4,2,0081: 2,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0101: 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,2,5,5,5,0121: 5,5,5,5,5,2,5,5,5,5,5,5,5,5,5,5,5,2,5,5,0141: 2,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0161: 5,5,5,5,5,5,5,2,5,5,2,5,5,5,5,5,5,5,5,5,0181: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,2,0201: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,2,5,0221: 5,5,5,5,5,5,5,5,5,5,5,5,5,2,5,5,5,5,5,5,0241: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0261: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0281: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,2,2,2,2,0301: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0321: 5,5,5,5,5,5,5,5,5,2,5,5,5,5,5,2,5,5,2,2,0341: 5,6,5,5,6,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0361: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0381: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0401: 5,5,5,5,5,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0421: 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,5,5,5,5,5,0441: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0461: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0481: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,2,5,5,5,5,5,0501: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0521: 5,5,5,5,5,2,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0541: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0561: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0581: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0601: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
Crawford and Padman (Oregon State U.)
Profile Quality Codes
I.D. (20 consecutive profiles)
0621: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,2,0641: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0661: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0681: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0701: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0721: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0741: 5,5,5,5,5,5,5,5,5,5,2,2,5,5,5,5,5,5,5,5,0761: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0781: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0801: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0821: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,2,5,0841: 5,5,5,5,5,5,5,5,5,5,5,5,5,2,5,5,2,2,5,5,0861: 2,5,5,5,5,5,5,5,5,2,5,5,5,5,5,2,2,5,5,5,0881: 5,5,5,5,5,5,5,5,5,5,5,2,5,5,5,5,5,5,5,5,0901: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0921: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,0941: 5,5,5,5,5,5,5,5,5,5,5,5,2,5,5,5,5,5,5,5,0961: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,2,2,5,5,5,0981: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1001: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1021: 5,5,5,5,5,5,5,5,2,2,5,5,5,5,5,5,5,5,5,5,1041: 2,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1061: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1081: 5,5,5,5,5,5,5,5,2,2,5,5,5,5,5,5,5,5,5,5,1101: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1121: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1141: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1161: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1181: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1201: 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,1221: 5,5,5,5,5,5,5,5,5,5,5
Table 6. Quality codes for RSVP profiles. The first column in each row gives the profile W.number for the first profile of each group of twenty profiles; the next twenty columns (given ascomma-separated values) indicate the quality code for profile number and the next nineteenprofiles in sequential order (thus, for the first row above, 0001 refers to RSVP profile # 0001,and the following 20 comma-separated values indicate the quality code for RSVP profiles #0001-
0020, respectively. See Table 5 for interpretation of the code values.)
25
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
BatchNumber
Number ofDrop Filesin Batch
Number ofGoodt
Drop Filesin Batch
FirstGoodt
Drop i.d.in Batch
Time of FirstGoodt Drop
i.d. (yearday)
LastGoodt
Drop i.d.in Batch
Time of LastGoodt Drop
W. (yearday)
0 170 67 8 116.0575 170 120.0822
1 126 122 172 120.4724 296 121.7066
2 113 101 301 122.6347 405 123.6669
3 116 89 436 124.9901 525 126.0531
4 114 113 527 126.6181 639 127.6666
5 111 110 641 128.6175 750 129.6664
6 106 102 753 130.0442 856 131.0825
cross-comparisons
4 2 859 131.8644 860 131.8813
7 115 109 862 132.5396 975 133.7291
8 113 108 978 134.4483 1088 135.5207
9 143 141 1091 136.4865 1231 137.5167
Total 1231 1064 - - - -
Table 7. RSVP batch drop summary.
t 'Good' here indicates that there are, at a minimum, good profiles of temperature and conductivity in the data set.
26
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
ADCP FileNumber
File Start Time File End Time Number ofEnsembles
Pulse Rep.Rate (x10-2 s)
Number ofSamples per
Ensemble
Number ofBins
PulseLength (m)
[approx]
1 04/25 16:23:00 04/25 16:44:49 22 40 150 60 2
2 04/25 17:05:35 04/25 18:45:35 101 40 140 60 2
3 04/25 19:10:10 04/25 23:58:10 289 40 140 60 2
4 04/26 01:09:22 04/26 17:48:22 1000 40 140 60 2
5 04/26 19:37:01 04/26 23:58:01 262 40 140 60 2
6 04/27 00:44:51 04/27 11:30:51 647 40 140 60 2
7 04/2711:51:00 04/2718:01:00 371 40 140 60 2
8 04/27 18:06:09 04/27 23:58:09 353 40 140 60 2
9 04/28 00:20:01 04/28 12:31:01 732 40 140 60 2
10 04/28 12:53:14 04/28 22:30:14 578 40 140 60 2
11 04/28 12:53:14 04/28 23:57:14 665 40 140 60 2
12 04/29 00:30:13 04/29 01:25:13 56 40 140 60 2
13 04/29 01:50:41 04/29 12:54:41 665 40 140 60 2
14 04/29 13:08:29 04/29 15:12:29 125 40 140 60 2
15 04/29 15:22:35 04/29 23:58:35 517 40 140 60 2
16 04/30 00:37:01 04/30 23:58:01 1402 40 140 60 2
17 05/0100:39:01 0510118:05:01 1047 40 140 60 2
18 05/01 18:30:28 05/0123:58:28 329 40 140 60 2
19 05/02 00:36:15 05/02 01:54:15 79 40 140 60 2
20 05/02 02:12:09 05/02 13:01:59 322 40 300 36 4
21 05/02 14:12:00 05/02 23:57:04 290 40 300 36 4
22 05/03 00:00:46 05/03 00:33:09 17 40 300 36 4
23 05/03 00:53:02 05/03 12:59:48 360 40 300 36 4
24 05/03 13:12:58 05/03 23:56:44 319 40 300 36 4
25 05/04 00:39:56 05/04 12:56:50 365 40 300 36 4
26 05104 13:07:56 05104 23:57:47 322 40 300 36 4
27 05/05 00:31:55 05/05 14:13:50 407 40 300 36 4
28 05/05 14:33:55 05/05 23:56:43 279 40 300 36 4
29 05/06 01:15:57 05/06 12:54:23 346 40 300 36 4
30 05/06 13:05:55 05/06 23:57:47 323 40 300 36 4
31 05/07 00:15:54 05/07 12:49:00 373 40 300 36 4
32 05/07 13:07:55 05/07 23:57:55 651 40 140 72 2
33 05/08 00:25:43 05/08 13:13:43 769 40 140 72 2
34 05/08 13:22:08 05/08 23:58:08 637 40 140 72 2
35 05/09 00:01:50 05/09 23:58:50 1438 40 140 72 2
36 05/10 00:17:35 05/10 23:58:35 1422 40 140 72 2
37 05/1100:16:41 05/11 23:58:41 1423 40 140 72 2
38 05/12 00:21:43 05/12 23:58:43 1418 40 140 72 2
39 05/13 00:13:41 05/13 23:58:41 1426 40 140 72 2
40 05/14 00:10:40 05/14 23:58:40 1429 40 140 72 2
41 05/15 00:08:39 05/15 23:58:39 1431 40 140 72 2
42 05/16 00:52:37 05/16 23:58:37 1387 40 140 72 2
43 05/17 00:00:34 05/17 23:58:34 1439 40 140 72 2
44 05/18 01:37:14 05/18 01:58:14 22 40 140 72 2
45 05/18 03:12:38 05/18 03:55:38 44 40 140 72 2
Table 8. Summary of ADCP settings.
27
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Depth(m)
Major AxisLength (mm/s)
Minor AxisLength (mm/s)
Angle ofInclination (de g.)
G(de)
G+(de)
G-(de g)
5.5 54 -3 15.3 145 129.7 160.4
9.3 51 -6 7.8 141.7 133.9 149.6
13 47 -5 6 140.7 134.8 146.7
16.8 51 -2 7 143.6 136.6 150.5
20.5 53 -1 9.6 145.5 135.9 155.1
24.3 55 -1 8.3 143.5. 135.3 151.8
28 60 -3 10.8 142.3 131.6 153.1
31.8 61 -7 11.4 141.4 130 152.8
35.5 59 -8 12.1 140.1 128 152.2
39.3 57 -6 11.8 141.5 129.6 153.3
43 56 -3 11.7 143.4 131.8 155.1
46.8 56 0 12.4 142.8 130.5 155.21
50.5 54 2 13.8 141.6 127.8 155.41
54.3 52 3 13 141.4 128.4 154.4
58 51 4 13.1 140.7 127.7 153.8
61.8 50 5 12.7 139.3 126.6 152
65.5 50 7 12.7 137.1 124.4 149.9
69.3 51 6 11 134.9 123.9 145.9
73 52 6 10.4 132.7 122.3 143
76.8 52 6 11.6 131.2 119.6 142.7
80.5 52 6 12.7 131.3 118.6 144
84.3 51 7 16.1 131.3 115.2 147.5
88 50 7 18.1 130.2 112.2 148.3
91.7 49 8 19.7 127.7 108 147.4
95.5 49 10 20.3 125.1 1104.9 145.4
99.2 49 11 20.6 122.8 1102.3 143.4
103 49 12 20.8 122 1101.2
106.7 49 11 22.6 122.9 1100.3 145.61
110.5 48 11 27.3 127.8- 100.5 155.1
114.2 47 10 33.6 T3 3.9 1100.3 167.41
Table 9. Tidal analysis results for K1 tidal constituent from 5 m to 115 m depth. Angle ofinclination denotes the clockwise rotation of the major axis relative to east. Positive values of theminor axis indicate counterclockwise rotation of the tidal component; negative values indicateclockwise rotation.
28
142.7
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Depth(m)
Major AxisLength (mm/s)
Minor AxisLength (mm/s)
Angle ofInclination (de g.)
G(de)
G+(de)
G-(de g)
5.5 19 0 5.6 105.5 100 111.1
9.3 20 -4 173.1 280.4 107.3 93.5
13 23 -2 170.7 283 112.3 93.7
16.8 23 -3 2.2 102.31 100.1 104-51
20.5 24 -7 172.4 284.7 112.3 97.1
24.3 26 -6 175.9 286.81 110.9 102.7
28 26 -8 179.7 288.71 108.9 108.4
31.8 26 -8 4 109.91105.9 113.9
35.5 25 -5 5.9 106.6 100.7 112.5
39.3 24 1 7.2 105.7 98.5 112.9
43 22 7 6 101.2 95.3 107.2
46.8 23 7 1.1 93.7 92.7 94.8
50.5 23 5 177.8 273.3 95.5 91.1
54.3 26 4 177.2 274.3 97.2 91.5
58 29 3 178.5 273.4 94.9 91.9
61.8 31 1 1.6 92.2 90.6 93.8
65.5 31 1 4.9 90.3 85.4 95.3
69.3 31 1 7.8 90.8 83 98.6
73 31 0 10.2 91.8 81.6 102
76.8 30 2 12.2 93.4 81.3 105.6
80.5 29 3 14.5 93.2 78.7 107.6
84.3 29 3 14.4 93.5 79.1 107.9
88 29 2 14.6 93.2 78.5 107.8
91.7 31 2 15 93.3 78.3 108.4
95.5 32 2 14.4 94.8 80.4 109.3
99.2 33 1 15.6 97.8 82.1 113.4
103 33 1 17.6 98.9 81.3 116.5
106.7 33 1 20.1 97.2 77.1 117.4
110.5 33 2 25.1 96.3 71.1 121.4
114.2 34 1 27.8 97.4 69.6 125.2
Table 10. Same as Table 9, but for 01 tidal constituent.
29
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Depth(m)
Major AxisLength (mm/s)
Minor AxisLength (mm/s)
Angle ofInclination (de g.)
G(de)
G+(de)
G-(de g)
5.5 63 32 5 27 22.1 32
9.3 75 22 4.5 27.1 22.6 31.6
13 99 -6 178.1 201.4 23.3 19.4
16.8 118 -23 179.4 207.3 27.9 26.8
20.5 121 -24 4.6 32 27.5 36.6
24.3 111 -14 13.2 37 23.8 50.2
28 95 2 23.6 43.8 20.2 67.4
31.8 85 16 30.4 50 19.6 80.4
35.5 77 24 32.8 53.1 20.3 86
39.3 73 27 33 54.3 21.3 87.4
43 71 27 32.2 54.2 22 86.4
46.8 70 28 29.2 53 23.7 82.2
50.5 69 29 24.5 48.2 23.7 72.7
54.3 68 27 18.8 42.6 23.8 61.4
58 71 25 14.1 37.7 23.6 51.7
61.8 73 23 12.1 36.4 24.3 48.5
65.5 74 21 13.7 36.5 22.8 50.3
69.3 74 21 14.5 37.1 22.6 51.6
73 76 20 15.9 38.4 22.5 54.3
76.8 78 18 18.6 40.6 22 59.2
80.5 79 17 21.3 42.6 21.2 63.9
84.3 80 16 24.2 43.8 19.6 68
88 80 17 25.4 44.7 19.3 70.1
91.7 79 18 27 45.6 18.6 72.6
95.5 78 20 28.2 46.7 18.4 74.9
99.2 76 22 29 47.4 18.3 76.4
103 72 25 30.5 49.1 18.5 79.6
106.7 68 27 32.9 51.4 18.5 84.2
110.5 63 30 38.2 55.9 17.7 94.2
114.2 58 33 46.7 63.7 16.9 110.4
Table 11. Same as Table 9, but for M2 tidal constituent.
30
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Depth(m)
Major AxisLength (mm/s)
Minor AxisLength (mm/s)
Angle ofInclination (de .)
G(de)
G+(de)
G-(de g)
5.5 29 12 56 111.8 55.8 167.8
9.3 36 10 38.9 97.1 58.1 136
13 40 4 35.6 95.4 59.7 131
16.8 28 14 24.9 84.7 59.8 109.7
20.5 36 4 173.9 235.9 61.9 49.8
24.3 44 -7 171.3 232.4 61.2 43.7
28 50 -10 172.5 233.9 61.4 46.4
31.8 46 -5 0.1 60.4 60.3 60.4
35.5 41 1 14.4 74.2 59.8 88.5
39.3 40 3 26.8 84.9 58.1 111.8
43 39 3 31.5 89.2 57.6 120.7
46.8 40 1 32.3 88.3 56 120.6
50.5 41 1 29.9 85.6 55.8 115.5
54.3 42 1 26.7 82.4 55.8 109.1
58 42 0 23.9 78.2 54.3 102.2
61.8 42 1 21.3 74.5 53.2 95.8
65.5 43 0 19.5 70.5 51 90
69.3 43 1 18.1 69.1 51 87.2
73 43 2 17 67.8 50.8 84.7
76.8 43 3 14 67.3 53.3 81.3
80.5 43 4 12.3 67.8 55.5 80.1
84.3 42 5 13.1 70.7 57.6 83.8
88 42 6 15 74 59 89
91.7 42 6 18.8 76.9 58.1 95.7
95.5 40 8 23.4 81.3 57.9 104.7
99.2 36 9 26.8 83.6 56.8 110.4
103 33 12 28.7 85.2 56.5 113.9
106.7 29 14 32 88.4 56.5 120.4
110.5 25 16 33.5 89.4 55.9 122.9
114.2 22 18 39.8 94.4 54.5 134.2
Table 12. Same as Table 9, but for S2 tidal constituent.
31
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Name ofTidal
Constituent
Frequency Major Axis or AxisLength(mm/s)
Angle ofInclination
(de g)
G(deg)
G+(deg)
G-(deg)
ZO 0 31 0 47.7 360 312.3 47.7
MSF 0.002822 17 -11 42.2 301.5 259.2 343.7
01 0.038731 20 -4 173.1 280.4 107.3 93.5
K1 0.041781 51 -6 7.8 141.7 133.9 149.6
M2 0.080511 75 22 4.5 27.1 22.6 31.6
S2 0.083333 36 10 38.9 97.1 58.1 136
M3 0.120767 6 -4 142.8 162.7 19.8 305.5
SK3 0./25/14 5 2 14.4 189.8 175.4 204.2
M4 0.161023 10 -7 126.1 283.4 157.3 49.5
MS4 0.163845 5 -3 88.2 42.2 314 130.4
S4 0.166667 5 -3 29.6 114.2 84.6 143.8
2MK5 0.202804 3 2 141.4 285.5 144.2 66.9
2SK5 0.208447 3 -1 116.8 172.7 55.9 289.6
M6 0.241534 2 -1 139.4 233.4 94.1 12.8
2MS6 0.244356 2 1 5.7 26.1 20.5 31.8
2SM6 0.247178 3 0 160.5 284.5 124 85.1
3MK7 0.283315 3 -1 168.7 311.4 142.7 120.2
M8 0.322046 3 0 131.9 302.8 170.9 74.7
Table 13. Entire 18-component tidal analysis for 9.3 m depth bin.
32
(cph) Length
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Name ofTidal
Constituent
Frequency Major Axis Minor Axis Angle ofInclination
(de g)
G(deg)
G+(deg)
G-(deg)
ZO 0 37 0 44 180 136 224
MSF 0.002822 22 -11 12.5 359.7 347.2 12.2
01 0.038731 26 -8 179.7 288.7 108.9 108.4
Ki 0.041781 60 -3 10.8 142.3 131.6 153.1
M2 0.080511 95 2 23.6 43.8 20.2 67.4
S2 0.083333 50 -10 172.5 233.9 61.4 46.4
M3 0.120767 7 -5 138.2 359.7 221.5 137.9
SK3 0./25/14 13 -6 3.9 221.6 217.6 225.5
M4 0.161023 11 -4 109 65.9 317 174.9
MS4 0.163845 7 -5 83 125.9 43' 208.9
S4 0.166667 3 -1 166.7 97.6 290.9 264.3
2MK5 0.202804 7 -2 146.4 120.1 333.7 266.5
2SK5 0.208447 2 0 33.2 181.4 148.2 214.7
M6 0.241534 4 -2 123.4 233.4 110 356.8
2MS6 0.244356 2 -1 152.4 247.4 95 39.8
2SM6 0.247178 3 0 151.9 354.3 202.4 146.1
3MK7 0.283315 6 -4 129.8 212.4 82.6 342.2
M8 0.322046 2 -1 164.2 120.8 316.5 285
Table 14. Same as Table 13, but for 28.0 m depth bin.
33
(cph) Length Length
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Name ofTidal
Constituent
Frequency Major AxisLength(mm/s)
Minor AxisLength(mm/s)
Angle ofInclination
(de g)
G(deg)
G+(deg)
G-(deg)
ZO 0 56 0 36.9 180 143.1 216.9
MSF 0.002822 30 -3 37.9 37.1 359.2 74.9
01 0.038731 23 5 177.8 273.3 95.5 -91.1
K1 0.041781 54 2 13.8 141.6 127.8 155.4
M2 0.080511 69 29 24.5 48.2 23.7 72.7
S2 0.083333 41 1 29.9 85.6 55.8 115.5
M3 0.120767 4 -3 129.6 92 322.3 221.6
SK3 0./25/14 8 -5 146.3 206.9 60.7 353.2
M4 0.161023 8 -6 134.3 119.9 345.6 254.3
MS4 0.163845 10 -6 112.5 194.4 81.9 307
S4 0.166667 2 -1 129.2 9.5 240.4 138.7
2MK5 0.202804 3 -1 119.3 54.8 295.5 174.2
2SK5 0.208447 3 -1 110.5 114 3.5 224.5
M6 0.241534 3 -1 74.5 42.8 328.3 117.4
2MS6 0.244356 5 -3 101.2 87.9 346.7 189.1
2SM6 0.247178 3 -1 120 129.4 9.4 249.4
3MK7 0.283315 1 1 167.2 107.8 300.6 275
M8 0.322046 1 0 166.9 134.6 327.7 301.5
Table 15. Same as Table 13, but for 50.5 m depth bin.
34
(cph)
Oceanographic Measurements in Resolute 1995 Crawford and Padman (Oregon State U.)
Name ofTidal
Constituent
Frequency(cph)
Major AxisLength(mm/s)
Minor AxisLength(mm/s)
Angle ofInclination
(de&)
G(deg)
G+(deg)
G-(deg)
ZO 0 36 0 34.9 180 145.1 214.9
MSF 0.002822 13 -5 55.7 42.5 346.8 98.1
01 0.038731 33 1 15.6 97.8 82.1 113.4
KI 0.041781 49 11 20.6 122.8 102.3 143.4
M2 0.080511 76 22 29 47.4 18.3 76.4
S2 0.083333 36 9 26.8 83.6 56.8 110.4
M3 0.120767 4 -3 155.3 230.2 74.9 25.5
SK3 0./25/14 4 1 69.7 161.8 92.1 231.5
M4 0.161023 4 -3 73.9 358.6 284.7 72.4
MS4 0.163845 6 -3 120.6 40.6 279.9 161.2
S4 0.166667 3 0 39.6 58.3 18.7 97.9
2MK5 0.202804 4 -2 33.4 31.8 358.4 65.2
2SK5 0.208447 1 0 77.3 86.6 9.3 164
M6 0.241534 2 0 36.8 317 280.2 353.9
2MS6 0.244356 3 -2 95.9 333.7 237.8 69.6
2SM6 0.247178 2 1 3.9 242.9 239 246.7
3MK7 0.283315 2 -1 103.2 144.4 41.2 247.6
M8 0.322046 1 0 86.3 239.5 153.2 325.8
Table 16. Same as Table 13, but for 99.2 m depth bin.
35
Oceanographic Measurements in Resolute 1995
k/ks G2(k/S)1.78 x
10"3
8.4211 x 10-23.16x10" 1.018x10-15.62 x 10"3 1.236 x 10"
1.00x10 1.497x10"1.78x10" 1.811x10"3.16x 10 2.196x 105.62 x 10-2 2.677 x 10"1.00 x
10"1
3.664 x 10"'1.78 x 10-1 3.463 x 103.16x10 2.185x10"5.01x10 -8.400 x 1
7.92 x 10-1 2.136 x 10"1.00 9.80 x 101.26 3.96 x 10"1.58 1.61 X 10-3
Crawford and Padman (Oregon State U.)
Table A-1. Discrete values of the universal shape function for the shear spectrum (after Oakey[ 1982] and Nasmyth [ 19701). The data have been re-written from Table Al in Oakey [ 1982] in termsof wavenumber instead of cyclic wavenumber.
36
ViscountMelville Sound
I ,--1 S
VictoriaIs.
NORTHIWEST TERRITORIES
FoxeBasin
Figure 1.1a: Map of the Canadian Arctic Archipelago. The Res95 experimental site is inBarrow Strait, in the center of the archipelago. A finer-scale view of the regionimmediately surrounding the camp is shown in Figure 1.1b (following page).
750
740
IntrepidPassage
Lowther
+00' (o' Island(
RUSSELLISLAND
Garrett I.
PEELSOUND
CORNWALLISISLAND
GriffithIsland
BARROW STRAIT
SOMERSETISLAND
Figure 1.1b: Map of the central Barrow Strait region, showing more detail in the areaindicated by a box in Figure 1.1a. Bathymetric contours in (b) are given in meters. TheRes95 camp is located around 74° 27.398' N, 97° 15.788' W, southeast of Lowther Island.
LOWTHER ISLANDICE CAMP
April, May 1995
Surveyed byL. Guy Millette
#3 Transducer30 North of
Goudeau Pt.
Gourdeau Point
S4 55° co
aepui 103111
0 50
meters
Gourdeau Point
Main Science Hutdepth 152 m
o McPhee FrameLiving tent 13k
camp benchmark
(c) Camp Position:Reference
74°27.381' N97°15.772' W
WGS 84
Biology Camp
McGill ADCPo
depth 158 m
Gourdeau Point
sducet A,(., ;%U PV`-"#3TCa
W L.P. mooring
GQ ac`sMarsden ADCP 280
A saesP Jce?l
depth 158 m Ma
11Z
S4
depth 151 m
S4 orientation
Gourdeau Point (0°)
Figure 1.2: Locations of primary instrumented sites at the Res95 camp.
WAS
140115 120 125 130 135
Resolute Data Summary
RSVP
1111111 11/11/1111ADCP
MOORING
Year Day
Figure 1.3: Time lines of good, calibrated data for each of the instrument packagesdiscussed in this report.
/3/N
RSVP/CTD/Bottles Main
2 0 043
-10 A D C P
Scribe Mark
GourdeauPt.
ScienceHut
Figure 1.4: A schematic showing the location of the two hydroholes inside the mainscience tent and the orientation of the transducers.
Figure 1.5: A portion of a synthetic aperture radar (SAR) image, obtained by the Elks-1 satelliteon May 2, 1995 (year day 122) showing the study site. The image (which has been rotated so thatthe top of the page is in the northward direction) consists of 8 bit pixels, corresponding touncalibrated backscattered intensity. Pixel resolution is roughly 100 in by 100 in. Lowther Islandis clearly identifiable. The ice camp was located on land-fast first-year ice; the medium graymasses along the coast of Lowther Island and to the northeast of the study site represent land-fast, multi-year ice (SAR image data provided by G. Reynolds, Alaska SAR Facility, Universityof Alaska Fairbanks [data take i.d. EI/S/19860.01; image W. 183735200]).
-1.4
-1.45
-1.5
-1.55
-1.6
-1.65
-1.7
-1.75
-1.85
-1.3
-1.35
Res95 Moored Thermistor Time Series - Selected Depths
11 120 125 130 135 140Year Day
Figure 2.1: Moored temperature time series from selected depths (125, 75, 25, 7 m).Sampling interval is one minute.
125m
75m
25m
7m
LI
—I
32.4
32.2
32
31.8Cl)a
31.4
31.2
Res95 Moored CTD Salinity Time Series
31L115 120 125 130 135 140
Year Day
Figure 2.2: Moored salinity time series from the three CTDs (30, 15, 7 m). Samplinginterval is one minute.
8
10
12
1
T (°C)-1.40
-1.45
-1.50
-1.55
-1.60
-1.65
-1.70
-1.71
-1.72
-1.73
=1.74
-1.75
-1.76125 130 135
Day-of-year (UTC: 1995)
Figure 2.3: Mooring temperature as a function of depth and time.
140
icy-3 102
120 125 130 135
yI I
I
102
MDR-106 (50m) - Temperature Data Comparisons
a)
TO -1.6a)CLEmF-
-1.8L115
100
fl.U0105
00
10 10
10-2 10-1
10-2 10-1 100 101Frequency (cph)
Figure 2.4: Temperature data from MDR 106 (50 m depth). Top panel shows the entiretemperature time series. Middle panel displays the log-log plots of the power spectraldensity, PSD, of the raw time series (blue), the low-pass-filtered time series (green), andthe low-pass-filtered, subsampled time series (red). Bottom panel shows same data as themiddle panel, plotted here as the frequency times the PSD on a log-linear scale. Filtercutoff period is 1 h; raw sampling interval is 1 min.; time interval for subsampled data is30 min. See text for more details on the filtering, subsampling, and spectral estimation.
Julian Da
100
10-10
00 1
Year Day
100 101 102
10-3 10 ' 10
32.4
-
U)0-
10-2
SBE-40 (30m) - Salinity Data Comparisons
125
10'
102 10-1
100f (cph)
Figure 2.5: Salinity data from SBE 40 (30 in depth). Top panel shows the entire salinitytime series. Middle panel displays the log-log plots of the power spectral density, PSD,of the raw time series (blue), the low-pass-filtered time series (green), and the low-pass-filtered, subsampled time series (red). Bottom panel shows same data as the middlepanel, plotted here as the frequency times the PSD on a log-linear scale. Filter cutoffperiod is 1 h; raw sampling interval is 1 min.; time interval for subsampled data is 30min. See text for more details on the filtering, subsampling, and spectral estimation.
raw (no filter)
filtered
filtered/decimated
Res95: McGill Water Level and Bottom Water Temperature
120 125 130Year Day
135 140
Figure 2.6: Time series of measurements from the McGill sensor mounted on theseabed: (a) water level (height of water above the sensor); (b) bottom water temperature.
Res95 RSVP Drop 180: Fall Speed Profile
-20
-40
E
-60am0
-80
-100
-120`-1.5 -1.4 -1.3 -1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5
Speed (m/s)
Figure 3.1: Fall speed profile for drop number 180. The profiler is seen to quicklyaccelerate to its terminal velocity of about -1.25 ms -1 (a negative value here impliesdescent) and to continue to fall at about that speed throughout the water column.' Theprofiler is quickly arrested at the end of the profile near 110 in depth.
Mean Temperature Profile - Batch #20
10
20
60
70
80-1.75 -1.74 -1.73 -1.72 -1.71 -1.7 -1.69 -1.68 -1.67 -1.66 -1.65
Temperature (C)
Figure 3.2: Sample comparison of time-averaged temperature profiles from the mooring (opencircles), the uncorrected RSVP data (dashed line) and the corrected RSVP data (solid line),evaluated over the entire period of batch 2 (day 122.6347 to 123.6669). The RSVP averages arederived from the 256-point `block' averages and have been bin-averaged in I m depth bins.
Mean Conductivity Profile - Batch #2
25 25.4 25.6 25.8Conductivity (mS/cm)
26 26.2
Figure 3.3: Sample comparison of time-averaged conductivity data from the mooring (open circles),the uncorrected RSVP data (dashed line) and the corrected RSVP data (solid line), evaluated overthe entire period of batch 2 (day 122.6347 to 123.6669). The RSVP averages are derived from the256-point `block' averages and have been bin-averaged in 1 m bins.
Temperature Intercomparisons, Year Day 131
-1.7 -1.6 -1.55Temperature (C)
-1.5 -1.45 -1.4
Figure 3.4a: Comparison of temperature data during cross-calibration run on May 11 (year day131). The dotted line is from the McGill CTD at 2014 h; the solid line is from the RSVP profiler at2044 h; the dashed line is from the RSVP at 2109; open circles identify the minimum.and maximumvalues observed at the mooring between 2014 h and 2109 h.
Salinity Intercomparisons, Year Day 131
31.6 31.8 32 32.2Salinity (psu)
32.4 32.6 32.8
Figure 3.4b: Comparison of salinity data during cross-calibration run on May 11 (year day 131).The dotted line is from the McGill CTD at 2014 h; the solid line is from the RSVP profiler at 2044h; the dashed line is from the RSVP at 2109; open circles identify the minimum and maximumvalues observed at the mooring between 2014 h and 2109 h. The results suggest there is a nearlyuniform offset between the McGill salinity and the RSVP mooring salinity, corresponding to roughly0.04 to 0.09 psu. No attempt has been made at this stage to correct for this difference.
Depth Range vs. Drop Number, Batch #00
E -50
a0-100
-150
-150
20 40 60 80 100 120
Depth Range vs. Drop Number, Batch #1
140
180 200 220 240 260 280
160
Figure 3.5a: Depth range of valid RSVP data vs. RSVP drop number for Batches 0 and 1.
Depth Range vs. Drop Number, Batch #2
E -50
.rCLa)
a-100
-150'---' I I I I I I I I I I
300 310 320 330 340 350 360 370 380 390 400
Depth Range vs. Drop Number, Batch #30
E -50
-150420 440 460 480 500 520
Figure 3.5b: Depth range of valid RSVP data vs. RSVP drop number for Batches 2 and 3.
Depth` Range vs. Drop Number, Batch #4
TI
-1501 f - I I I I I 1 I I I 1
530 540 550 560 570 580 590 600 610 620 630
Depth Range vs. Drop Number, Batch #5
E -50
0a)
a-100
-150 I I I 1 I i I 1 I I 1
650 660 670 680 690 700 710 720 730 740 750
Figure 3.5c: Depth range of valid RSVP data vs. RSVP drop number for Batches 4 and 5.
Depth Range vs. Drop Number, Batch #6
E -50
-150760 770 780 790 800 810 820 830 840 850
Depth Range vs. Drop Number, Batch #7
E -50
-150" 1
860 880 900 920 940 960
Figure 3.5d: Depth range of valid RSVP data vs. RSVP drop number for Batches 6 and 7.
0
'. lDepth Range vs. Drop Number, Batch #8
0
E -50
tQ.a)c -100
-150980 990 1000 1010 1020 1030 1040 1050 1060 1070 1080
Depth Range vs. Drop Number, Batch #90
E -50
CLa)
o -100
-1501100 1120 1140 1160 1180 1200 1220
Figure 3.5e: Depth range of valid RSVP data vs. RSVP drop number for Batches 8 and 9.
Res95 RSVP Drop 653: Shear Time Series and Spectral Examples
2
U10 20 30 40
Tim50 (s)60 70 80 90 100
e
100
102
E9_10-4
106
100101
102kz(m-1)
103
Figure 3.6: Shear time series and frequency spectra for RSVP Drop 653. (a) Time seriesof shear from shear channel S 1, with times plotted relative to the beginning of datacollection for that profile. Two short, 256-point (1 second) data segments are selected,representing high and low regions of shear variance (labeled A and B, respectively).Drop speed was about 1.15 ms-' and very stable over most of the profile; A correspondsto about 32 m and B to 87 m depth. (b) Wavenumber power spectra for time series A(thick line) and B (thin line), plotted on a log-log scale as kZ cpM (kk) vs. kZ. No spectralaveraging is performed here; note that this is not an energy-preserving plot, but doesallow visualization over a very broad dynamic range. Dashed lines show theoreticalNasmyth spectra for different orders of magnitude of the dissipation rate, ranging from E= 10-9 to 10-5 m2s-3. At wavelengths greater than about 320 m-1 (denoted by a vertical line;f - 64 Hz), the spectra drop off sharply due to the frequency characteristics of the shearprobe and data collection scheme. In the low dissipation measurements, much of theenergy greater than 80 m-1 is probably due to electronic noise and profiler motion andvibrations.
Res95 RSVP Drop 1184: Shear Time Series and Spectral Examples
1 I I I
0 10 20 30 4050
60(s)Time
100 101 102k,(m-')
70 80 90 100
103
Figure 3.7: Similar to Figure 3.6, but for RSVP Drop 1184; data segments A and B correspond to10 m and 93 m depth, respectively; drop speed was steady at about 1.20 ms-1.
i
--r ------------- T120.7 120.9 121.1 121.3
Year Day
Figure 3.8: Stack plot summary of RSVP profi e data for batch(from top to bottom), temperature (T, in °C), sal nity (S, in psu),in cycles/hour), and dissipation rate (as logio[e], with a in mesa)
r
" 4-
Res95 RSVP Batch 1 Summary
0-1.5
E -40 0N -80
F-
-1.7-120
120.5 120.7 120.9 121.1 121.3 121.5 121.70 33
-- -40E 32 OLN -80 (/)
-120 31
120.5 120.7 120.9 121.1 121.3 121.5 121.70 20
- -40E Q
10
N -80 z
-120 0
120.5 120.7 120.9 121.1 121.3 121.5 121.70 -6
-40E
N
0rn0-80 -8
-120120.5 121.5 121.7
1 1. Panels representbuoyancy frequency (N,
_TiL 1;:-ThStJ*iluiirnr--J Res95 RSVP Batch 2 Summary
0
-40-1.5
E1 6N -80
- .
-1.7-120
122.7 122.9 123.1 123.3 123.50 33
-, -40 ME 32 Q-N -80 U)
-120 31
122.7 122.9 123.1 123.3 123.50 20
-, -40E
10N -80 z
-120 0122.7 122.9 123.1 123.3 123.5
0 -6
-40 w
E O_
0)N -80 0-8
-120
122.7 122.9 123.1 123.3 123.5Year Day
Figure 3.9: Same as Figure 3.8, for batch 2.
9z t8'9l
521931
931
931
Res95 RSVP Batch 3 Summary
0
-1.5-40
E -1.6U
N -80 ~-1.7
-120
125.2 125.4 125.6 125.80 33
-, -40 ME
N32 a-80 Cl)
-120 31
125.4 125.6 125.80 20
-- -40E
N10
-80 z
-120 0125.2 125.4 125.6
0 -6
-40E O
Nrn0-80 -8
-120125 125.2 125.4 125.6
Year Day
Figure 3.10: Same as Figure 3.8, for batch 3.
T
YI
M
l=
IN
_-!a rlMfi_.
- _
5'LZ L
I
11
e
I
I
I
1 t,
'ifo°L-11
Res95 RSVP Batch 4 Summary
0
- -40 -1.5E 0N
-1.0F--80
-1.7-120
126.7 126.9 127.1 127.30 33
-40E
32N -80 U)
-120 31126.7 126.9 127.1 127.3 127.5
0 20
-, -40E
10N -80 Z
-120 0126.7 126.9 127.1 127.3 127.5
0 -6
-40E 0
0)N -80 0-8
-120126.7 126.9 127.1 127.3 127.5
Year Day
Figure 3.11: Same as Figure 3.8, for batch 4.
PT
Res95 RSVP Batch 5 Summary
0
-1.5- -40
N -80-1.7
-120128.7 128.9 129.1 129.3 129.5
0 33
-40E un32 aN -80 U)
-120 31
128.7 128.9 129.1 129.3 129.50 20
-, -40E
10o
N -80 z
-120 0
128.7 128.9 129.1 129.3 129.50 -6
-- -40 wE O
0)N -80 0-8
-120128.7 128.9 129.1 129.3 129.5
Year Day
Figure 3.12: Same as Figure 3.8, for batch 5.
N
9 ,06 G
Res95 RSVP Batch 6 Summary
0
-1 5E -40 .
N -1 6-80 .
-1 7-120 .
130.1 130.3 130.7 130.90
33
-40
32 0.N -80
U)
-12031
130.1 130.30
20
-400.
10"' -80 Z
-120 0130.1 130.3
0 -6-40 w
0CIE-80 -8 0
120130.1 130.3 130.5
Year Day130.7 130.9
Figure 3.13: Same as Figure 3.8, for batch 6.
9'eC l
££l
N
B
££L
Res95 RSVP Batch 7 Summary
0
-1.5-40 U
-1.6-80
-1.7120
132.6 132.8 133.2 133.4 133.60 33
-- -40E
32N -80 U)
-120 31
132.6 132.8 133.2 133.4 133.60 20
- -40E
10Q
N -80 z
-120 0132.6 132.8 133.2 133.4 133.6
0 -6
-40E 0
rnN -80 -8 0
-120
132.6 132.8 133 133.2Year Day
133.4
Figure 3.14: Same as Figure 3.8, for batch 7.
(w)z
(w)z
Res95 RSVP Batch 8 Summary
0
-- -40E
N -80
-1.5
-1.6
-1.7-120
134.7 134.9 135.10 33
-40
32Cl)
-80
120 31134.5 134.7 134.9 135.1
0 20
-40CL
10-80 z120 0
134.5 134.7 134.9 135.1 135.3 135.50 -6
w-40E 06N -80 0-8
-120134.5 134.7 134.9
Year Day135.1 135.3 135.5
Figure 3.15: Same as Figure 3.8, for batch 8.
________
-!_____________________
Res95 RSVP Batch 9 Summary
0
-40E
N -80
-1.5
-1.6
-1.7-120
136.5 136.7 136.9 137.1 137.3 137.50 33
-40E 32 Q-N -80
-120 31
136.7 136.9 137.1 137.3 137.50 20
-40 0E 10 yN -80 z
-120 0
136.9 137.1 137.3 137.50 -6
-40 OE CM
0N -80 -8
-120136.5 136.7 136.9 137.1 137.3 137.5
Year Day
Figure 3.16: Same as Figure 3.8, for batch 9.
-
-40
-80
Averaged Speed of Sound Profile from All Valid RSVP Profiles0
-20
E
-60aN0
-100
-11436 1437 1438 1439 1440 1441 1442
Speed of Sound (m/s)
Figure 4.1: Average sound speed profile (solid line), as determined from the RSVP data.The dashed lines represent plus or minus one standard deviation.
120
120
125 130
130
135 140
140
120 135 140
Res95: ADCP-Raw Eastward Velocity Component, vX50
x>
-50115
50
x>
-50'115
50
125 135
-50'115 125 130
Year Day
Figure 4.2: Time series of raw, ADCP-derived measurements of eastward (v,,) velocityat specified depths: (a) 9.3 m; (b) 50.5 m; (c) 99.2 m. The reduction in high-frequencyvariability between day 122 and day 127 is primarily a consequence of a longer pulsewidth and an increased number of samples per ensemble (see Table 8).
50
50
Res95: ADCP Raw Northward Velocity Component, vy
-50115
50
0
-50 L--115
(a)
(b)
(c)
120 125 130 135
120 125 130 135
140
140
-50'115 120 125 130 135 140
Year Day
Figure 4.3: Same as for Figure 4.2, but for northward (vy) velocity.
1
i
I I -
q
- i4.i -Ref'.. Z.' `l
I I
20
-20115
20
-20115
20
CO
EU
N
0
(a)
(b)
(c)
C
Res95: ADCP Raw Vertical Velocity Component, vz
120 125 130 135
120 125 130 135
140
140
-20115 120 125 130 135 140
Year Day
Figure 4.4: Same as for Figure 4.2, but for vertical (vi) velocity.
Res95: ADCP Raw Error Velocity Component, very20
0
-20115
20
0
-20 L-115
20
0
(a)
120 125 130 135 140
(b)
120 125 130 135 140
(c)
-20'115 '120 125 130 135 140
Year Day
Figure 4.5: Same as for Figure 4.2, but for the error velocity (verr).
1
fib)
y-----------------I
ADCP Velocities: Low Frequency and Tidal Reconstruction (9.3 m)20
10
10
-30120 120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
20
10
0E0
-20Low Frequency
- - Tidal Analysis
-30120 120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
Year Day
Figure 4.6: Comparison of low-frequency velocities (solid lines) and reconstructedvelocities (dashed lines) from tidal analysis at 9.3 m depth: (a) eastward component; (b)northward component. Time interval shown for the plotted data is 1 hour; time range islimited to a 5 day section for ease of comparison.
I
(b)
ADCP Velocities: Low Frequency and Tidal Reconstruction (28 m)20
10
-3020120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
20
10
Low Frequency- - Tidal Analysis
-3120120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
Year Day
Figure 4.7: Same as for Figure 4.6, but for 28 m depth.
/ 1
VVI --' V/1
I
ADCP Velocities: Low Frequency and Tidal Reconstruction (50.5 m)20
10
E 00x -10
120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
20
10
CO
E 0U
-10
L F-20
ow requency
- - Tidal Analysis
-3120120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
Year Day
Figure 4.8: Same as for Figure 4.6, but for 50.5 m depth.
TTZT
(b)
I
4-
ADCP Velocities: Low- Frequency and Tidal Reconstruction (99.2 m)20
10
-3020120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
20
10
Low Frequency- - Tidal Analysis
-3120120.5 121 121.5 122 122.5 123 123.5 124 124.5 125
Year Day
Figure 4.9: Same as for Figure 4.6, but for 99.2 m depth.
'-00
N6
6
Normalized Cumulative Integration of Nasmyth Shear Spectra
4-0c
0.40CZi
Figure A.1: Cumulative integration of Nasmyth shear spectra, cp,, normalized to the total shearvariance, for several values of dissipation rate, E. Integrations were carried out numerically, based onvalues of G2(k/kc) given by Oakey (1982). For the range of e typically found in the ocean(10-9<F<10-5 m2s-3), most of the spectral energy occurs at wavenumbers between about 12 m-1 and320 m-1 ; for E=10-9-10-8 m2s"3, most of the energy occurs between 12 m-1 and 80 m-1.
rl
1I
7
II
Ii
gt(k 1,k2,c) for fixed k1 and k2
0.8
0.6
C4N
0.4
[k1,k2] = [12m -1,320m
[k1,kz] = [12m -1,80m -1 ]
0.2
0-10
10109 108 107 106 105
10-4
s(m2s-3)
Figure A.2: Estimates of g,, the fraction of the variance in the Nasmyth shear spectrum, captured ina fixed spectral wavenumber band [ki, k2], as a function of dissipation rate, E. Two differentwavenumber bands are shown: [k1, k2] = [12 m'', 80 m'] and [kI, k2] = [12 m', 320 m"'].
1
gt(k-,,k2,E tP ) for fixed k, and k2
.11
' [k,,k2] = [12m '1, 320m -1 ]
0.8
°'0.4
0.2
[k,,k2] = [12m -1, 80m -1 ]
1011 1010 109 108 10' 106 10510-4
£tP (m2 s-3)
Figure A.3: Estimates of g,, the fraction of the variance in the Nasmyth shear spectrum,captured in a fixed spectral wavenumber band [k1, k2], as a function of the partialestimate, E,p. Two different wavenumber bands are shown: [k1, k2] _ [12 m , 80 m-'] and[k1, k2] = [12 m 1, 320 m-1]. A horizontal line denotes the minimum threshold of gt = 0.75required for determining observational estimates of c from integrations of observed shearspectra (see Appendix).
6
N
I
Res95 RSVP Drop #1184: Dissipation Algorithm Comparison
-20
-40
E
0
J
-80
-100
2-16 Hz
- - 2-64 Hzadaptive
-110-10 109 108107 106
Dissipation Rate (m^2/s^3)
Figure A.4: Comparison of energy dissipation profile estimates for RSVP drop number1184 for three algorithms with different high-frequency cutoff values: f2 = 16 Hz (thinsolid line),f2 = 64 Hz (dashed line), and a variable f2 (from the adaptive method; thicksolid line). All three methods use the same low-frequency cutoff, f, = 2 Hz, and makecorrections for energy not included in the spectral range of integration (see Appendix).
0
-40
0
-20 -20
-40
E E
W -60 - -60Q Qm a.0 0
-80 -80
-100 -100
-12010_1°10-8
10-6Dissipation Rate (m^2/s^3)
-120' -I
'
10 20 30 40 50High Frequency Cutoff (Hz)
Figure A.5: (a) Dissipation profile for RSVP drop number 1184, obtained using theadaptive method; (b) associated high frequency cutoff value, f2i used by the method. Theminimum threshold value of f2 = 16 Hz is clearly identified. When the energy levels in theshear spectra are high, the algorithm integrates to higher frequencies (wavenumbers) toget a better estimate of the shear variance.