Skip to main content

Description

A global Group for High Resolution Sea Surface Temperature (GHRSST) Level 2P data set containing multi-channel Sea Surface Temperature (SST) retrievals derived in real-time from the Advanced Very High Resolution Radiometer (AVHRR) level-1B data from the Meteorological Operational-A (MetOp-A) satellite. The SST data in this data set are used operationally in oceanographic analyses and forecasts by the US Naval Oceanographic Office (NAVO). The MetOp satellite program is a European multi-satellite program to provide weather data services for monitoring climate and improving weather forecasts. MetOp-A, MetOp-B and Metop-C were respectively launched on 19 Oct 2006, 17 September 2012 and 7 November 2018. The program was jointly established by the European Space Agency (ESA) and the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) with the US National Oceanic and Atmospheric Administration (NOAA) contributing the AVHRR sensor. AVHRR instruments measure the radiance of the Earth in 5 (or 6) relatively wide spectral bands. The first two are centered around the red (0.6 micron) and near-infrared (0.9 micron) regions, the third one is located around 4 (3.6) micron, and the last two sample the emitted thermal radiation, around 11 and 12 micron, respectively. The legacy 5 band instrument is known as AVHRR/2 while the more recent version, the AVHRR/3 (first carried on the NOAA-15 platform), acquires data in a 6th channel located at 1.6 micron. Typically, the 11 and 12 micron channels are used to derive SST sometimes in combination with the 3.5 micron channel. The swath of the AVHRR sensor is a relatively large 2400 km. All MetOp platforms are sun synchronous and generally view the same earth location twice a day (latitude dependent). The ground native resolution of the AVHRR instruments is approximately 1.1 km at nadir and degrades off nadir. This particular data set is produced from legacy Global Area Coverage (GAC) data that are derived from a sample averaging of the full resolution global AVHRR data. Four out of every five samples along the scan line are used to compute on average value and the data from only every third scan line are processed, yielding an effective 4 km spatial resolution at nadir. The v2.0 is the updated version from current v1.0 with extensive algorithm improvements and upgrades. The major improvements include: 1) Significant changes in contaminant/cloud detection; 2) Increased the spatial resolution from 9 km to 4 km; 3) Updated compliance with GDS2, ACDD 1.3, and CF 1.6; and 4) Removed the dependency on the High-resolution Infrared Radiation Sounder (HIRS) sensor (only available to MetOp-A/B), thus allowing for the consistent inter-calibration and the processing of MetOp-A/B/C data

Product Summary

Platforms
METOP-A
Instruments
AVHRR-3
Spatial Extent

N: 80 S: -70 E: 180 W: -180

Spatial Resolution
4000 Meters x 4000 Meters
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2020-06-29
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC) ,
Naval Oceanographic Office, U.S. Navy, U.S. Department of Defense (DOD/USNAVY/NAVOCEANO)
Concept ID
C2036877495-POCLOUD
Data State
ACTIVE
Number of Files/Granules
7079
Processing Level
2P
Published
Updated
Science Keywords
Sea Surface Temperature

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

DOD/USNAVY/NAVOCEANO. (2020). GHRSST Level 2P Global Sea Surface Temperature v2.0 from the AVHRR on the MetOp-A satellite produced by NAVO [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/GHMTA-2PN20 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
adi_dtime_from_sst time difference with NAAPS forecast hour byte -128 -127 to 127 0.1
aerosol_dynamic_indicator Aerosol optical depth provided from the Navy Aerosol Analysis and Prediction System (NAAPS) global aerosol prediction system. count byte -128 -127 to 127 0.006
brightness_temperature_4um non L2P core field; brightness temperature for 3.7 um channel AVHRR channel 3 kelvin short -32768 -5000 to 5000 0.01
brightness_temperature_11um non L2P core field; brightness temperature for 10.8 um channel AVHRR channel 4 kelvin short -32768 -5000 to 5000 0.01
brightness_temperature_12um non L2P core field; brightness temperature for 12.0 um channel AVHRR channel 5 kelvin short -32768 -5000 to 5000 0.01
dt_analysis Deviation from NAVOCEANO 10-km SST gridded field (K10) kelvin byte -128 -127 to 127 0.1
l2p_flags no retrieval made on land or ice. SST over lakes and river are not identified N/A short 2048 0 to 2047 1
lat Latitude of retrievals degrees_north float N/A -90 to 90 1
lon Longitude of retrievals degrees_east float N/A -180 to 180 1
quality_level Based on NAVOCEANO reliability estimates N/A byte -1 0 to 5 1
satellite_zenith_angle satellite zenith angle angular_degree byte -128 -127 to 127 1
sea_surface_temperature SST obtained by regression from buoy measurements at 1 m depth kelvin short -32768 -5000 to 5000 0.01
sses_bias Updated daily based on previous month match-ups kelvin byte -128 -127 to 127 0.01
sses_standard_deviation Updated daily based on previous month match-ups kelvin byte -128 -127 to 127 0.01
sst_dtime time to be added to the reference time to determine actual time of retrieval second short -32768 -32767 to 32767 0.25
time seconds since 1981-01-01 00:00:00 seconds since 1981-01-01 00:00:00 int N/A N/A 1
wind_speed wind speed is not available m s-1 byte -128 -127 to 127 0.15
You're viewing 17 of 17