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O. T. E. Submarine volcanic heat flux and hydrography: perspectives from Northeast Pacific observations, theory, and experiments Proposed dissertation for Scott Veirs in the UW School of Oceanography. Approach :. Central question : - PowerPoint PPT Presentation
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O
ET
Central question:
How do plumes and currents interact above the Main Endeavour vent field to affect the measurement of hydrothermal
heat flux?
Approach:
Submarine volcanic heat flux and hydrography: perspectives from Northeast Pacific
observations, theory, and experiments
Proposed dissertation for Scott Veirs in the UW School of Oceanography
Endeavour Segment of the Juan de Fuca RidgeFlow Mow cruise (August, 2000) study site
HIGH BUOYANCY FLUX FIELDS:
SDF = Salty Dawg
HRF = High Rise
MEF = Main Endeavour
MF = Mothra
LOW BUOYANCY FLUX FIELDS:
C = Cirque
D = Dune
CB = Clam Bed
Q = Quebec
New or suspected fields Bathymetric contour interval: 100m
Main Endeavour hydrothermal vent fieldAxial valley bathymetry and key hydrographic observations
1 km
100mCTD
current
vents
1995
2000
Overview of current and hydrographic observations
MEF Sea floor
Ridge crest
m above MEF sea
floor
2210
1850
2100
Depth
250
50
150
200
100
2168
2070
2000
1900
1800
~350
ABE survey
CTD “ribbon”
CTD “curtain”
CTD “VOC”Upper control volume
Lower control volume
400m wide
800m long ~500m N&S
Hydrographic variability I
Hydrographic variability II
Currents in the MEF vicinity
~200m NE of MEF, 1995 ~1km S of MEF, 2000
depth/mab 2175/25 1900/300 2168/15 1968/215
Mean [cm/s] 1 to N 5 to SW 1 to N 5 to SSW
Max [cm/s] 5 67 9 13
q_adv
Sea floor
Ridge crest
250
50
150
200
100
mab 2200
1800
2100
Depth
q_sidesq_top
q_focused + q_diffuse + q_conduct
MEF heat flux calculation
q ~ AU, = ref + (z/Sz)(S-Sref)
Synthesis through “puff” models
Plume distributions in stratified, oscillatory cross flow
Current and surface waves
Oscillating jet
Lam and Xia, May, 2001
• Translate source with stepper moter• Concentration field from light sheet(s) and conductivity probeConductivity probe
Carriage
Stratified fluid
Interconnecting observation, theory, and experiment
Observations
Assumptions
Approaches
Products
CTD Currents MEF/sources
q_top +
q_sides
q_adv q variance
Puff model Lab workq~AU
definition and interpolation, A integration, U extrapolation; Scaling, dimensional analysis; Advection
dominates rotation
Frequencies with dominant spectral power:
Vertical coherence: 10-100m
Horizontal coherence: >50km
Other sources of data?
• rotary above the ridge crest
• rectified within the axial valley
• mean flows at both levels
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