Algorithm Descriptions

The Ocean Biology Processing Group (OBPG) produces and distributes a standard suite of ocean color products for all compatible sensors at Level-2 and Level-3, plus sea surface temperature (SST) products from MODIS and VIIRS. The OBPG also produces a suite of Level-3 evaluation products. The descriptions and references for these standard and evaluation products (provided below) are intended to satisfy the Algorithm Theoretical Basis Document (ATBD) requirement as defined by the NASA Earth Observing System Project Science Office.

Ocean Color Products

Flags: View quality indicators of Level-2 Ocean Color products.

Standard

Remote Sensing Reflectance (Rrs; sr^-1)

The at-surface spectral remote-sensing reflectances observed by the satellite instrument after atmospheric correction. The aerosol optical thickness and aerosol Ångström exponent products are also described.

Chlorophyll a (chlor_a; mg m^-3)

The concentration of the photosynthetic pigment chlorophyll a

Diffuse attenuation coefficient for downwelling irradiance at 490 nm (Kd; m^-1)

The diffuse attenuation coefficient for downwelling irradiance over the first optical attenuation layer

Particulate Organic Carbon (POC; mg m^-3)

The concentration of particulate organic carbon

Particulate Inorganic Carbon (PIC; mol m^-3)

The concentration of particulate inorganic carbon

Photosynthetically Available Radiation (PAR; Einstein m^-2 d^-1)

Daily mean photosynthetically available radiation at the ocean surface

Instantaneous Photosynthetically Available Radiation (iPAR; Einstein m^-2 s^-1)

PAR at the ocean surface at the time of the satellite observation

Normalized Fluorescence Line Height (nFLH; mW cm^-2 µm^-1 sr^-1)

Relative measure of water-leaving radiance associated with chlorophyll fluorescence

Inherent Optical Properties from GIOP Algorithm (IOP, m^-1)

Spectral marine absorption and backscattering coefficients of water column constituents

Provisional/Developmental

PIC - Color Index

Color index for calcite describes

Special

Inherent Optical Properties from GSM Algorithm (GSM; m^-1)

Spectral marine absorption and backscattering coefficients of water column constituents

Inherent Optical Properties from QAA Algorithm (QAA; m^-1)

Spectral marine absorption and backscattering coefficients of water column constituents

Euphotic Depth from Lee Algorithm (ZLEE; m^-1)

Depth of the euphotic zone

Land Reflectance from NDVI algorithm (LAND)

Land reflectance generated from the Normalized Difference Vegetation Index (NDVI) algorithm

Test

Net Primary Productivity (NPP) from VGPM algorithm

(coming soon)

Net Primary Productivity (NPP) from VGPM/Eppley algorithm

(coming soon)

Calcite (ci2)

Calcite concentration derived from particulate inorganic carbon

Sea Surface Temperature Products

Flags: View quality indicators of SST products.

Standard

11 µm Sea Surface Temperature (SST; °C)

Sea surface temperature derived from long-wave (11-12 µm) thermal radiation

4 µm Sea Surface Temperature (SST4; °C)

Sea surface temperature derived from short-wave (3-4 µm) thermal radiation

Triple-Window Sea Surface Temperature (SST3; °C)

Sea surface temperature returned in three mid- and long-wave infrared bands

Developmental

This section lists algorithms that have been proposed and are under review. If accepted, the status will be updated to "Provisional" or "Standard". As developmental algorithms, those listed below ARE NOT used in OBPG data processing.

Aerosol correction for VIIRS SST

Aerosol correction for sea surface temperature

Physical Deterministic (PD) SST

Sea surface temperature using a physical deterministic method