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 UCSB
outline PJW, NASA/SSAI, 6 Jun UCSB the ocean color community; its infrastructure & data archives satellite data product validation; algorithm development “status report” progress within the community; GSFC field work & team
the ocean color community PJW, NASA/SSAI, 6 Jun UCSB U.S. & international academic, research, & government institutions NASA Ocean Biology & Biogeochemistry Program GSFC Ocean Ecology Branch
PJW, NASA/SSAI, 6 Jun UCSB data processing & distribution SeaDAS Aquarius & NPP Ocean PEATE satellite calibration & validation SeaBASS Ocean Biology Processing Group field program support office HPLC analysis team field & satellite sensor development ocean carbon research & laboratory
NASA Ocean Biology & Biogeochemistry (OBB) Program PJW, NASA/SSAI, 6 Jun UCSB 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
SeaBASS data archive PJW, NASA/SSAI, 6 Jun UCSB AOPs, IOPs, carbon stocks, CTD, pigments, aerosols, etc. continuous & discrete profiles; some fixed observing or along-track
in situ data in support of operational ocean color “cal/val” PJW, NASA/SSAI, 6 Jun UCSB satellite data product validation satellite vicarious calibration (instrument + algorithm adjustment) bio-optical algorithm development, tuning, & evaluation
satellite data product validation: discrete match-ups PJW, NASA/SSAI, 6 Jun UCSB
satellite data product validation: discrete match-ups PJW, NASA/SSAI, 6 Jun UCSB in situ Chl SeaWiFS Chl % Frequency
satellite vicarious calibration (~ discrete match-ups) PJW, NASA/SSAI, 6 Jun UCSB S.W. Bailey, et al. “Sources and assumptions for the vicarious calibration of ocean color satellite observations,” Appl. Opt. 47, (2008)
satellite data product validation: population statistics PJW, NASA/SSAI, 6 Jun UCSB Chesapeake Bay Program routine data collection since cruises / year 49 stations 19 hydrographic measurements algal biomass water clarity dissolved oxygen others
satellite data product validation: population statistics PJW, NASA/SSAI, 6 Jun UCSB Chl-a (mg m -3 ) PJW, NASA/SSAI, 27 Apr 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, (2009).
bio-optical algorithm development PJW, NASA/SSAI, 6 Jun UCSB “empirical” “semi-analytical” R rs statistically related to pigments, IOPs, carbon stocks, etc. spectral matching of R rs & IOPs
in situ data in support of operational ocean color “cal/val” PJW, NASA/SSAI, 6 Jun UCSB spatial & temporal distributions “complete” suites of measurements (R rs, IOPs, biogeochemistry)
SeaBASS data archive PJW, NASA/SSAI, 6 Jun UCSB AOPs, IOPs, carbon stocks, CTD, pigments, aerosols, etc. continuous & discrete profiles; some fixed observing or along-track
SeaBASS holdings by year: PJW, NASA/SSAI, 6 Jun UCSB
coincident SeaWiFS & in situ data PJW, NASA/SSAI, 6 Jun UCSB
coincident SeaWiFS & in situ data
valid SeaWiFS-in situ match-ups PJW, NASA/SSAI, 6 Jun UCSB
bio-optical algorithm development data sets PJW, NASA/SSAI, 6 Jun UCSB Rrs & Chl & absorption & backscattering R rs R rs & Chl R rs & Chl & absorption
bio-optical algorithm development data sets PJW, NASA/SSAI, 6 Jun UCSB R rs R rs & Chl
bio-optical algorithm data sets PJW, NASA/SSAI, 6 Jun UCSB
moving forward: new missions PJW, NASA/SSAI, 6 Jun UCSB 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
moving forward: community innovations PJW, NASA/SSAI, 6 Jun UCSB AERONET (fixed-above water platforms) buoy networks gliders, drifters, & other autonomous platforms longitude depth latitude towed & underway sampling
GSFC Field Program Support & HPLC Analysis PJW, NASA/SSAI, 6 Jun UCSB GSFC Ocean Ecology Branch Joaquin Chaves Scott Freeman Aimee Neeley Jeremy Werdell SeaBASS TBD Crystal Thomas Tech TBD Stan Hooker Chuck McClain Veronica Lance (post-doc) Antonio Mannino Mike Novak Chuck McClain, Branch Head
PJW, NASA/SSAI, 6 Jun UCSB GSFC Field Program Support & HPLC Analysis capabilities: AOPs IOPs HPLC pigments phytoplankton communities carbon stocks nutrients support: 1 large field campaign / year 2-3 small field campaigns / year 1-2 data analysis workshops / year
questions & comments? PJW, NASA/SSAI, 6 Jun UCSB
satellite ocean color PJW, NASA/SSAI, 6 Jun 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, R rs ) 2. relate spectral R rs to C a (or geophysical product of interest) 3. spatially / temporally bin and remap satellite C a observations satellite ocean color PJW, NASA/SSAI, 6 Jun UCSB
visible light wavelength (nm) near-infraredultra-violet SeaWiFS channels radiance, L, in units of W cm -2 nm -1 sr -1 surface 0o0o reflectance, R = L incident irradiance, E satellite ocean color PJW, NASA/SSAI, 6 Jun UCSB
different water masses, different L w … one suite of algorithms? satellite ocean color PJW, NASA/SSAI, 6 Jun UCSB