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IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
IOP Algorithm Workshop @ OOXIX
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
Fri / Sat workshop generic agenda:
9:00 start
10:30 break
12:30 lunch
13:30 resume
15:30 break
17:30 end
22:00 group dinner (Fri)
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
focus topics:
1. overview
2. end-user perspectives
3. operational implementation strategies
4. relationships between Rrs and IOPs
5. regional adjustment of SAA parameterization
6. new directions
7. summary, recommendations, & steps forward
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 1 - overview (mod by Jeremy)
topics:
summarize goals, approaches, evaluation process, & limitations
goals:
clear understanding of workshop goals
agreement on evaluation process & metrics
agreement on accuracy of SAA summaries
recognition of overlap amongst approaches
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
what we’re (NASA, anyway) looking to do:
extend the IOCCG SAA survey by
(1) evaluating application of SAA algorithms to satellite radiometry
(2) reviewing & consolidating SAA construction
workshop motivation & goal:
achieve community consensus on an effective algorithmic approach for producing global-scale, remotely sensed SAA IOP products
what we’re (NASA, anyway) looking for:
combination of accuracy and geographic coverage
flexible, multi-sensor implementation
computational efficiency to support operational environment
open source software and accompanying LUTs
associated SAA uncertainties
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
algorithm “sh
oot out”
you’ve been warned:
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 1 - overview (mod by Jeremy)
topics:
summarize goals, approaches, evaluation process, & limitations
goals:
clear understanding of workshop goals
agreement on evaluation process & metrics
agreement on accuracy of SAA summaries
recognition of overlap amongst approaches
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
process:
SAA identification: literature review (IOCCG report 5); community solicitation
open
SAA consolidation: identification of (dis)similarities
software accumulation: standalone versions & l2gen (SeaDAS) import
evaluation prep: define metrics; design analyses; identify test data sets
“validation” analyses
sensitivity studies
community dialog
workshop: consolidate recom-mendations; ideas
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
pre-workshop achievements - overview
1. process: a philosophy & a path forward
2. software: l2gen (msl12) & l3gen & IDL, Matlab, C, etc.
3. dialog: public record of (forum for) issues & ideas
4. shared analyses (evaluation, sensitivity, etc.)
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
pre-workshop achievements - dialog & discussion
1. air-sea transmission, Rrs rrs(0-)
2. calculation of Rrs (bandpass correction, f/Q)
3. temperature & salinity dependence of aw & bbw
4. spectral data products to be considered (adg, bb, etc.)
5. evaluation metrics & SAA failure conditions
6. inversion methods & linearization issues
7. calculation of uncertainties
8. SAA product validation & sensitivity analyses
9. strategies to produce level-3 products
http://oceancolor.gsfc.nasa.gov/forum/oceancolor/board_show.pl?bid=24
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
pre-workshop achievements - analyses
1. in situ-to-in situ & satellite-to-in situ match-ups
2. global (level-3) comparisons
3. spatial coverage (level-2) comparisions
4. sensitivities to parameterization & noisy input
5. sensitivity to inversion method
6. level-2 vs. level-3 inversion
http://oceancolor.gsfc.nasa.gov/MEETINGS/OOXIX/IOP/analyses.html
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
available metrics:
posted analyses …
( for 400 < < 700 )
Rrs() > 0
adg() & a() > -0.005
bbp() > -0.0001
coverage …
retrieval quality / comparison …
available metrics:
level-3 flagging …
( for 400 < < 600 )
Rrs() > 0 (?)
-0.95 aw() < a() < 5
-0.05 aw() < adg() < 5
-0.05 aw() < a() < 5
-0.95 bbw() < bb() < 0.015
-0.05 bbw() < bbp() < 0.015
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 1 - overview (mod by Jeremy)
topics:
summarize goals, approaches, evaluation process, & limitations
goals:
clear understanding of workshop goals
agreement on evaluation process & metrics
agreement on accuracy of SAA summaries
recognition of overlap amongst approaches
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
anatomy of a semi-analytical algorithm (SAA):
many approaches are similarly constructed & parameterized
next, I’ll deconstruct the SAAs to illustrate similarities & differences
the goal is to convince you that most SAAs fall within 2 / 3 categories of construction & that most have interchangeable parts
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
€
Rrs =ℜfQ
bb
a + bb
⎛
⎝ ⎜
⎞
⎠ ⎟
satellite provides Rrs()
a () and bb () are desired products
€
bb = bbw + bbii=1
n
∑
€
a = aw + aii=1
n
∑
total a and bb are sums of coefficients for all components in seawater
€
=bbw + M i bbii=1
n
∑
€
=aw + M i a ii=1
n
∑
each coefficient expressed as product of magnitude and spectral shape
€
=aw + M dgadg + Mφaφ
€
bb = bbw + bbp
€
=bbw + Mbpbbp
€
a = aw + adg + aφ
€
adg = exp S λ 0 − λ[ ]( )
€
bbp = λ η
€
aφ λ( )
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
€
adg = exp S λ 0 − λ[ ]( )
€
bbp = λ η
€
aφ λ( )
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
GSM, HL, BR
€
ℜ f /Q
Gordon quad;Lee trans
€
adg = exp S λ 0 − λ[ ]( )
€
bbp = λ η inversion
variable S variable
€
aφ
simultaneous:nonlinear (L-M), matrix inversion
a variable
€
rrs (0− ,λ ) ≈
bbw (λ )+ Mbpbbp (λ )
aw (λ )+ M dgadg (λ )+ Mφaφ (λ )+ bbw (λ )+ Mbpbbp (λ )
system of 5/6 equations with 3 unknowns
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
a = a - aw - adg
LUT
calculate a
empiricala(555)
iterationa(i,j)
estimate adg(i) usingS, adg(i,j), and a(i,j)
QAA
PML, NIWA
€
ℜ f /Q
Gordon quad;Lee trans
€
bbp = λ η
variablecalculate a
€
adg = exp S λ 0 − λ[ ]( )
€
aφ
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
solution
bb and a both fromKd, bw/b, and solz
LUT
LAS
€
ℜ f /Q calculate Kd
LUT
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
GSM, HL, BR
€
ℜ f /Q
Gordon quad;Lee trans
a = a - aw - adg
€
adg = exp S λ 0 − λ[ ]( )
€
bbp = λ η inversion
variable S variable
€
aφ
simultaneous:nonlinear (L-M), matrix inversion
a variable
LUT
calculate a
empiricala(555)
iterationa(i,j)
estimate adg(i) usingS, adg(i,j), and a(i,j)
QAA
solution
bb and a both fromKd, bw/b, and solz
PML, NIWA
€
ℜ f /Q
Gordon quad;Lee trans
€
bbp = λ η
variablecalculate a
€
adg = exp S λ 0 − λ[ ]( )
€
aφ
LUT
LAS
€
ℜ f /Q calculate Kd
LUT
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
ag
p(4
43)
bbp
(44
3)
current state-of-the-art:
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
algorithm #1
alg
ori
thm
#2
diff
ere
nce
glo
bal deep w
ate
r
adg(555)retrievals
adg(555)difference
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 1 - overview (mod by Jeremy)
topics:
summarize goals, approaches, evaluation process, & limitations
goals:
clear understanding of workshop goals
agreement on evaluation process & metrics
agreement on accuracy of SAA summaries
recognition of overlap amongst approaches
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
GSM (standard)
QA
A (
standard
)
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
GSM (QAA , QAA S, Bricaud a )
QA
A (
standard
)
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
GSM (standard)
QA
A (
GSM
,
GS
M S
)
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
GSM (standard)
QA
A (
GSM
,
GS
M S
, G
SM
a(5
55) )
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 2 - end-user perspectives (mod by Mike)
topics:
desired products & their uses
accuracy / behavior uncertainty requirements
goals:
list(s) near- & long-term needs (with attention to what’s available)
list(s) of data product hierarchy / priority
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 3 - operational implementation strategies (mod by Bryan)
topics:
L2 Rrs - l2gen, f/Q & normalization, bandpass corrections
L3 IOPs - masks, geometry, calc @ L2 vs L3, other strategies
goals:
consensus understanding of L2 Rrs generation
agreeement on SAA flags & their use in L3 product generation
discussion of (dis)advantages of product generation at L2 vs. L3
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 4 - relationships b/w Rrs and IOPs (mod by Emmanuel)
topics:
IOP shape functions; inversion procedures; uncertainties; ambiguity
goals:
discussion of sensitivities of shape functions & inversion procedures & how they impact product accuracies & geographic coverage
discussion of methods for uncertainty determination
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 5 - regional adjustment of SAA params (mod by Mark/Tim)
topics:
Dowell/Moore optical water type classification approach; others?
goals:
consensus (dis)agreement of need to pursue such approaches
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 6 - new directions (mod by Samantha)
topics:
GlobColour; fluorescence; f/Q & normalization(s); others?
goals:
illumination
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
backup slides
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
questions to be answered:
1. SAAs predefine spectral shapes for the IOP products of interest. What are the key components & can their sensitivities, uncertainties, & relative priority be defined?
2. How critical / sensitive is the optimization or inversion method used?
3. How does spectral resolution effect the retrievals?
4. How do the SAAs perform:
a. relative to in situ IOPs using in situ Rrs?
b. relative to in situ IOPs using satellite Rrs (from a match-up data set)?
c. on various satellite level-2 & level-3 scenes
5. Do the conclusions of #1-4 vary by trophic level or bioregime?
6. What are the remediations to failure?
7. What is the most appropriate implementation strategy for operational satellite data processing (e.g., level-2 Rrs normalization, masking & binning at level-3?
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 2 - end-user perspectives (mod by Mike)
recommendations:
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 3 - operational implementation strategies (mod by Bryan)
recommendations:
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 4 - relationships b/w Rrs and IOPs (mod by Emmanuel)
recommendations:
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 5 - regional adjustment of SAA params (mod by Mark/Tim)
recommendations:
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
topic 6 - new directions (mod by Samantha)
recommendations:
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
(dis)advantages of various modeling approaches:
empirical
straightforward (Rrs product) & computationally efficient
biased to in situ database & degrades with optical complexity
SAA / quasi-SAA
configurable form & simultaneous output of multiple products
only as representative as model assumptions (including empirical functions)
LUT
based on exact RTE calculations & simultaneous output of products
only as representative and flexible as RTE model assumptions
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
attendees:
Antoine Mangin (ACRI) Odile Hembise Fanton d’Andon (ACRI)
Bryan Franz (NASA) Paula Bontempi (NASA)
Catherine Brown (LOV) Samantha Lavender (U. Plymouth)
Emmanuel Boss (U. Maine) Sean Bailey (NASA)
Gene Feldman (NASA) Stephane Maritorena (UCSB)
Hubert Loisel (U. Littoral) Takafumi Hirata (PML)
Jeremy Werdell (NASA) Tim Moore (NURC)
Jill Schwarz (NIWA) Tim Smyth (PML)
Mark Dowell (JRC) Yannick Huot (LOV)
Mike Behrenfeld (OSU) ZhongPing Lee (MSU)
unable to attend: Andre Morel (LOV), Paul Lyon (NRL)
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
IOP Algorithm Workshop, Ocean Optics XIX, 3-4 Oct 2008, PJW
NASA/SSAI
€
Rrs =ℜfQ
bb
a + bb
⎛
⎝ ⎜
⎞
⎠ ⎟
€
adg = exp S λ 0 − λ[ ]( )
€
bbp = λ η
€
bb = bbw + bbi = bbw + M i bii=1
n
∑i=1
n
∑
€
a = aw + adg + aφ = aw + M dgadg + Mφaφ
€
a = aw + ai = aw + M i a ii=1
n
∑i=1
n
∑
€
bb = bbw + bbp = bbw + Mbpbbp
€
rrs (0− ,λ ) ≈
bbw (λ )+ Mbpbbp (λ )
aw (λ )+ M dgadg (λ )+ Mφaφ (λ )+ bbw (λ )+ Mbpbbp (λ )