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Description

A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.25 degree grid at the NOAA National Centers for Environmental Information. This product uses optimal interpolation (OI) by interpolating and extrapolating SST observations from different sources, resulting in a smoothed complete field. The sources of data are satellite (AVHRR) and in situ platforms (i.e., ships and buoys), and the specific datasets employed may change over. At the marginal ice zone, sea ice concentrations are used to generate proxy SSTs. A preliminary version of this file is produced in near-real time (1-day latency), and then replaced with a final version after 2 weeks. Note that this is the AVHRR-ONLY (AVHRR-OI), available from September 1, 1981, but there is a companion SST product that includes microwave satellite data, available from June 2002.

Product Summary

Platforms
NOAA-11 ,
NOAA-14 ,
NOAA-9 ,
NOAA-16 ,
NOAA-17 ,
NOAA-19 ,
BUOYS ,
NOAA-7
Instruments
AVHRR-2 ,
AVHRR-3 ,
DRIFTING BUOYS
Spatial Extent

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

Spatial Resolution
0.25 Decimal Degrees x 0.25 Decimal Degrees
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
1981-09-01 to 2020-04-05
Data Partner
National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce (DOC/NOAA/NESDIS/NCEI) ,
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2499940505-POCLOUD
Data State
ACTIVE
Number of Files/Granules
14096
Processing Level
4
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

NCEI. (2016). GHRSST Level 4 AVHRR_OI Global Blended Sea Surface Temperature Analysis (GDS version 2) from NCEI [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/GHAAO-4BC02 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
analysed_sst Single-sensor Pathfinder 5.0/5.1 AVHRR SSTs used until 2005; two AVHRRs at a time are used 2007 onward. Sea ice and in-situ data used also are 'near real time' quality for recent period. SST (bulk) is at ambiguous depth because multiple types of observations are used. kelvin short -32768 -300 to 4500 0.01
analysis_error Sum of bias, sampling and random errors. kelvin short -32768 0 to 32767 0.01
lat Uniform grid with centers from -89.875 to 89.875 by 0.25 degrees. degrees_north float N/A -90 to 90 1
lat_bnds This variable defines the latitude values at the north and south bounds of every 0.25-degree pixel. N/A float N/A N/A 1
lon Uniform grid with centers from -179.875 to 179.875 by 0.25 degrees. degrees_east float N/A -180 to 180 1
lon_bnds This variable defines the longitude values at the west and east bounds of every 0.25-degree pixel. N/A float N/A N/A 1
mask Binary mask distinguishing water and land only. N/A byte -128 1 to 2 1
sea_ice_fraction 7-day median filtered . Switch from 25 km NASA team ice (http://nsidc.org/data/nsidc-0051.html) to 50 km NCEP ice (http://polar.ncep.noaa.gov/seaice) after 2004 results in artificial increase in ice coverage. 1 byte -128 0 to 100 0.01
time Nominal time because observations are from different sources and are made at different times of the day. seconds since 1981-01-01 00:00:00 int N/A N/A 1
time_bnds This variable defines the start and end of the time span for the data. N/A int N/A N/A 1
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