1. Remote Sensing of the Ocean and Coastal Waters
Prof. Alexander Gilerson
Department of Electrical Engineering

2. Melin, 2013

4. Remote Sensing of Water Regions
RS of water areas provides an efficient way of monitoring water quality, biomass in the ocean, sediment plumes, spatial and temporal scales of the water structures, sea surface temperature, etc.
Phytoplankton are a very
important part of ocean life:
Phytoplankton are the first link in the food chain.
Phytoplankton convert nutrients into plant material by using sunlight through photosynthesis and convert carbon dioxide from sea water into organic carbon and oxygen as a by-product and thus affect carbon balance.
Amount of phytoplankton in the ocean can be traced by the concentration of the optically active pigment chlorophyll [Chl]

5. Phytoplankton types
For most regions of the world, the color of the ocean is determined primarily by the abundance of phytoplankton and associated photosynthetic pigments, especially Chl.

6. Reflectance spectra for the open ocean
[Chl] can be well characterized by blue-green ratio
With increasing [Chl] water changes its color from blue to green
SeaWiFS Blue-Green Ratio Algorithm
From K. Carder, et al. ,2003

7. Chlorophyll Global and Regional Maps
SeaWiFS, July 2006
MODIS, NE and Florida coasts

8. Water Composition for the Open Ocean and Coastal Waters
In the open ocean algae are the main component
In coastal waters algae are mixed with CDOM and minerals
Algae CDOM* Minerals
*CDOM is the colored dissolved organic matter mostly of terrestrial origin

9. Reflectance of Various Surfaces
Signal from water is small in comparison with reflectance from other surfaces and atmosphere

10. EAS 42700/B5100 – Class 5 March 6, 2017, NY L A L R L w
Remote Sensing – Ocean Color
EAS 42700/B5100 – Class 5
March 6, 2017, NY
Satellite sensor
Sun
Atmospheric scattering & absorption
air molecules, greenhouse gasses
(CO2, O3, NO2), water vapor,
aerosols, dust, smoke
L A
L R
L w
Reflection from water surface
In-water attenuation
Water molecules
Phytoplankton
 Colored Dissolved Organic Matter (CDOM)
 Non-algal particles (NAP)
Transmission through water-air boundary
Bottom reflection 10

11. EAS 42700/B5100 – Class 2 February 6, 2017, NY Unites States Japan
Ocean Remote Sensing – History
EAS 42700/B5100 – Class 2
February 6, 2017, NY
GOCI ( present)
The first GEO ocean color sensor (not global)
PACE (launch in 2022)
Unites States
Japan
India
Europe
Korean
Landsat 9 (launch in 2020)
GOCI-II (launch in 2018)
HICO ( )
“Proof of concept” for high resolution hyper-spectral
100 m res
124 bands
(not global)
OLCI/Sentinel (2016- present)
Landsat - 8 (2013-present)
VIIRS NPP ( present)
The “proof of concept” – Global datasets
MODIS Terra ( present)
MODIS Aqua ( present)
“State of the art”
SeaWiFS ( )
Revolutionized Ocean color research.
Planned
for 5
Years.
Global
coverage
OCM - 2 ( present)
GLI ( )
MERIS ( )
OCM ( )
MOS ( )
CZCS ( )
OCTS ( )
1980
1990
2000
2010
2020
2030

12. MODIS Spectral Bands for Ocean Color and Atmospheric Correction

13. Launch of NASA Suomi NPP satellite – October 2011

14. McClain, 2013

15. Main goals in retrieval from ocean color imagery
CHL concentration
In addition, especially in coastal waters:
CDOM concentration
Concentration of minerals
Particle size distributions
Types of phytoplankton species

16. Spectra in conditions of Red Tide
Red part of the spectra is very strong

17. Applications

18. Field measurements NJ cruise, R/V Connecticut, 2008 Our partners:
NRL - SSC, DC
NASA – GSFC, LARC
NOAA - NESDIS
Creighton University, NE;
University of Nebraska, NE,
University of Connecticut
Old Dominion University, VA
University of Texas
Texas A&M University
WET Labs Inc
Norfolk, VA 2009 – validation of CALIPSO and Glory missions
NY Harbor

19. Underwater measurements

20. Validation Cruise in Summer 2014
R/V Endeavor owned by NSF operated by University of Rhode Island, 185 feet, crew -12, scientists -18

21. Validation of satellites
LISCO Multispectral SeaPRISM system
as part of AERONET – Ocean Color network +HyperSAS
LISCO
[Zibordi et al., 2006]
Identical measuring systems and protocols, calibrated using a single reference source and method, and processed with the same code;
 Standardized products of exact normalized water-leaving radiance and aerosol optical thickness

22. SeaPRISM and HyperSAS instruments installed on the tower
SeaPRISM data are transmitted through the satellite to NASA AERONET group. Processed data are posted on AERONET site
HyperSAS data are transmitted through broadband over IP to the CCNY server 22

23. Tower with the instruments and solar panels on the platform in LIS23

24. Time Series Remote Sensing Reflectance (Rrs) [sr-1]
Satellite Validation
Satellite data
Reprocessing 2009
Time Series Remote Sensing Reflectance (Rrs) [sr-1]
 Consistency in seasonal variations observed from the platform and from space 24