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Description

MODIS (or Moderate-Resolution Imaging Spectroradiometer) is a key instrument aboard the Terra (EOS AM) and Aqua (EOS PM) satellites. Terra's orbit around the Earth is timed so that it passes from north to south across the equator in the morning, while Aqua passes south to north over the equator in the afternoon. Terra MODIS and Aqua MODIS are viewing the entire Earth's surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths (see MODIS Technical Specifications). These data will improve our understanding of global dynamics and processes occurring on the land, in the oceans, and in the lower atmosphere. MODIS is playing a vital role in the development of validated, global, interactive Earth system models able to predict global change accurately enough to assist policy makers in making sound decisions concerning the protection of our environment.

Version Description

Reprocessing of Ocean Color (OC) Datasets

Product Summary

Platforms
Aqua
Instruments
MODIS
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Geographic Region
GLOBAL OCEAN
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2002-07-04 to Present
Data Partner
Ocean Biology Processing Group (OBPG) ,
Ocean Biology Distributed Active Archive Center (OB.DAAC), Global Change Data Center, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/GCDC/OB.DAAC)
Concept ID
C3427336480-OB_CLOUD
Data State
ACTIVE
Number of Files/Granules
66594
Processing Level
4
Published
Updated
Science Keywords
Absorption

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

NASA Ocean Biology Processing Group. (2025). Aqua MODIS Level-4 Global Mapped Garver-Siegel-Maritorena Model (GSM) Data, version 2022.0 [Data set]. NASA Ocean Biology Distributed Active Archive Center. https://doi.org/10.5067/AQUA/MODIS/L4M/GSM/2022.0 Date Accessed: 2025-12-14

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
adg_443_gsm Absorption due to gelbstoff and detrital material at 443 nm, GSM algorithm m^-1 int16 -32767 -30000 to 25000 9.9999997473788E-5
bbp_443_gsm Particulate backscattering at 443 nm, GSM algorithm m^-1 int16 -32767 -27999 to 1999 4.9999998736894E-6
chl_gsm Chlorophyll Concentration, GSM model mg m^-3 float32 -32767 0.0010000000474975 to 100 N/A
lat Latitude degrees_north float32 -999 -90 to 90 N/A
lon Longitude degrees_east float32 -999 -180 to 180 N/A
palette palette N/A uint8 N/A N/A N/A
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