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Description

The Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) is a well calibrated passive microwave radiometer, similar to the Special Sensor Microwave Imager (SSM/I), that contains lower frequency channels required for sea surface temperature (SST) retrievals. The TRMM is part of the NASA's mission to planet Earth, and is a joint venture between NASA and the Japan Aerospace Exploration Agency (JAXA) to measure precipitation, water vapor, sea surface temperature (SST) and surface wind in the global tropical regions and was launched in 27 November 1997 from the Tanegashima Space Center in Tanegashima, Japan. The TRMM satellite travels west to east in a 402 km altitude semi-equatorial processing orbit that results in day-to-day changes in the observation time of any given earth location between 38S and 38N. Remote Sensing Systems (REMSS) has produced a Version-7.1a TMI SST dataset for the Group for High Resolution Sea Surface Temperature (GHRSST) by applying an algorithm to the 10.7 GHz channel through a removal of surface roughness effects. In contrast to infrared SST observations, microwave retrievals can be measured through clouds, which are nearly transparent at 10.7 GHz. Microwave retrievals are also insensitive to water vapor and aerosols. The algorithm for retrieving SSTs from radiometer data is described in "AMSR Ocean Algorithm."

Product Summary

Platforms
TRMM
Instruments
TMI
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
1997-12-08 to 2015-01-01
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2617176783-POCLOUD
Data State
COMPLETE
Number of Files/Granules
6226
Processing Level
3
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

Remote Sensing Systems. (2017). GHRSST Level 3U Global Subskin Sea Surface Temperature from TMI onboard TRMM satellite [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/GHTMI-3UR71 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
cloud_liquid_water non L3U core field kg m-2 byte -128 -127 to 127 0.01
confidence_flag b0:1=within 50km rain, 0.6 dif mwoisst;b1:1=within 100km rain, 0.8 dif mwoisst;b2:1=within 150km ice, 0.6 dif mwoisst;b3:1=more than 5deg dif mwoisst;b4:1=3-sigma test;b5:1=(tmi only) within 150 km of land and 0.6 warmer than mwoisst;b6:1=diurnal estimate > 0.3 warming;b7:1=diurnal estimate > 1.0 warming N/A byte N/A N/A 1
cool_skin non L3U core field K byte -128 -127 to 127 0.01
diurnal_amplitude non L3U core field K byte -128 -127 to 127 0.02
dt_analysis delta SST K byte -128 -127 to 127 0.1
l2p_flags These flags can help use the data N/A short N/A 0 to 2047 1
lat Latitude of retrievals degrees_north float -32768 -89.875 to 89.875 1
lon Longitude of retrievals degrees_east float -32768 -179.875 to 179.875 1
proximity_confidence 1=Bad, data rejected;2=Suspected Bad, data that has any confidence flags bit 0-5 thrown;3=Unprocessed proximity confidence flag, should be Good data;4=Good data N/A byte N/A N/A 1
quality_level This flag can help use the data N/A byte -128 0 to 5 1
rain_rate non L3U core field mm hr-1 byte -128 -127 to 127 0.1
rejection_flag b0:1=rain;b1:1=high wind/sunglint;b2:1=ice;b3:1=near land;b4:1=no data;b5:1=land; N/A byte N/A N/A 1
sea_ice_fraction ftp://eclipse.ncdc.noaa.gov/pub/OI-daily-v2/IEEE/YYYY/AVHRR/avhrr-only-v2.YYYYMMDD.gz 1 byte -128 -127 to 127 0.01
sea_surface_temperature Microwave SST = approximately the top 1 milimeter K short -32768 -5000 to 5000 0.01
sses_bias Sensor Specific Bias from in situ SSTs K byte -128 -127 to 127 0.01
sses_standard_deviation Sensor Specific STD from in situ SSTs K byte -128 -127 to 127 0.01
sst_dtime relative time of SST observations second int -32768 0 to 10000 10
time useful to help interpret sst_dtime seconds since 1981-01-01 00:00:00 int N/A N/A 1
water_vapor non L3U core field kg m-2 byte -128 -127 to 127 0.3
wind_speed non L3U core field; wind_speed_lf m s-1 byte -128 -127 to 127 0.2
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