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PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
In situ science in support of satellite ocean color objectives
Jeremy Werdell
NASA Goddard Space Flight Center
Science Systems & Applications, Inc.
6 Jun 2011
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
outline
the ocean color community; its infrastructure & data archives
satellite data product validation; algorithm development
“status report”
progress within the community; GSFC field work & team
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
the ocean color community
U.S. & international academic, research, & government
institutions
NASA Ocean Biology & Biogeochemistry
Program
GSFC Ocean Ecology Branch
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
GSFC Ocean Ecology Branch
data processing & distributionSeaDAS
Aquarius & NPP Ocean PEATE
satellite calibration & validationSeaBASS
Ocean Biology Processing Group
field program support office
HPLC analysis team
field & satellite sensor
development
ocean carbon research & laboratory
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
NASA Ocean Biology & Biogeochemistry (OBB) Program
field work funded by OBB Program
in situ data submitted to NASA SeaBASS (GSFC) within
1-year
in situ data publicly released
in situ data used to validate satellite data products & to
develop / evaluate algorithms
in situ used to calibrate satellite
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
SeaBASS data archive
AOPs, IOPs, carbon stocks, CTD, pigments, aerosols, etc.
continuous & discrete profiles; some fixed observing or along-track
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
in situ data in support of operational ocean color “cal/val”
satellite data product validation
satellite vicarious calibration (instrument + algorithm adjustment)
bio-optical algorithm development, tuning, & evaluation
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
satellite data product validation: discrete match-ups
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
satellite data product validation: discrete match-ups
in situ Chl
Sea
WiF
SChl % Frequency
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
satellite vicarious calibration (~ discrete match-ups)
S.W. Bailey, et al. “Sources and assumptions for the vicarious calibration of ocean color satellite observations,” Appl. Opt. 47, 2035-2045 (2008)
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
satellite data product validation: population statistics
Chesapeake Bay Program
http://www.chesapeakebay.net
routine data collection since 198412-16 cruises / year
49 stations19 hydrographic measurements
algal biomasswater claritydissolved oxygenothers
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
satellite data product validation: population statisticsC
hl-
a (
mg
m-3)
PJW, NASA/SSAI, 27 Apr 2011, @ HPL
P.J. Werdell et al., “Regional and seasonal variability of chlorophyll-a in Chesapeake Bay as observed by SeaWiFS and MODIS-Aqua,” Rem. Sens. Environ. 113, 1319-1330 (2009).
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
bio-optical algorithm development
“empirical” “semi-analytical”
Rrs statistically related to pigments, IOPs, carbon stocks, etc.
spectral matching of Rrs & IOPs
€
Rrs (λ )∝bb (λ )
a(λ ) + bb (λ )
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
in situ data in support of operational ocean color “cal/val”
spatial & temporal distributions
“complete” suites of measurements (Rrs, IOPs, biogeochemistry)
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
SeaBASS data archive
AOPs, IOPs, carbon stocks, CTD, pigments, aerosols, etc.
continuous & discrete profiles; some fixed observing or along-track
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
SeaBASS holdings by year: 2006-2009
2009
2006 2007
2008
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
coincident SeaWiFS & in situ data
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
coincident SeaWiFS & in situ data
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
valid SeaWiFS-in situ match-ups
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
bio-optical algorithm development data sets
Rrs & Chl & absorption & backscattering
Rrs Rrs & Chl
Rrs & Chl & absorption
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
bio-optical algorithm development data sets
Rrs Rrs & Chl
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
bio-optical algorithm data sets
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
moving forward: new missions
dynamic range of problem set is growing:
• new missions emphasize research in shallow, optically complex water
• new missions emphasize “new” products (carbon, rates, etc.)
• spectral domain stretching to UV and SWIR• new missions have immediate, operational requirements
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
moving forward: community innovations
AERONET (fixed-above water platforms)
buoy networks
gliders, drifters, & other autonomous platforms
longitude
de
pth
latitude
towed & underway sampling
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
GSFC Field Program Support & HPLC Analysis
GSFC Ocean Ecology Branch
Joaquin ChavesScott FreemanAimee NeeleyJeremy WerdellSeaBASS TBD
Crystal ThomasTech TBD
Stan HookerChuck McClain Veronica Lance (post-
doc)Antonio ManninoMike Novak
Chuck McClain, Branch Head
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
GSFC Field Program Support & HPLC Analysis
capabilities:AOPsIOPsHPLC pigmentsphytoplankton communitiescarbon stocksnutrients
support:1 large field campaign / year2-3 small field campaigns / year1-2 data analysis workshops / year
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
questions & comments?
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
satellite ocean color
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
SEA SURFACE
TOP-OF-THE-ATMOSPHERE
the satellite views the spectral light field at the top-of-the-atmosphere
SATELLITE
PHYTOPLANKTON
1. remove atmosphere from total signal to derive estimate of light field emanating from sea surface (remote-sensing reflectance, Rrs)
2. relate spectral Rrs to Ca (or geophysical product of interest)
3. spatially / temporally bin and remap satellite Ca observations
satellite ocean color
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
visible light
wavelength (nm)
near-infraredultra-violet
443412 490510 555 670 765 865
8 SeaWiFS channels
radiance, L, in units of W cm-2 nm-1 sr-1
surface
0o
reflectance, R =
L
incident irradiance, E
satellite ocean color
PJW, NASA/SSAI, 6 Jun 2011, @ UCSB
different water masses, different Lw …
one suite of algorithms?
satellite ocean color
