NASA GHRC Collaboration between NASA MSFC and The University of Alabama in Huntsville
  • Access Data
    • Dataset List (HyDRO)
      • View a list of all GHRC dataset holdings using our custom search tool, HyDRO.
    • Search (HyDRO)
      • HyDRO is GHRC's custom dataset search and order tool.

        With HyDRO, you can search, discover, and filter GHRC's dataset holdings.

        HyDRO will also help you find information about browse imagery, access restrictions, and dataset guide documents.
    • NASA Earthdata Search
      • Earthdata is NASA's next generation metadata and service discovery tool, providing search and access capabilities for dataset holdings at all of the Distributed Active Archive Centers (DAACs) including the GHRC.
    • Latest Data (HyDRO)
      • View the latest additions to our data holdings using HyDRO.
  • Measurements
  • Field Campaigns
    • Hurricane Science
      • GHRC has worked with NASA's Hurricane Science Research Program (HSRP) since the 1990's. We are the archive and distribution center for data collected during HSRP field campaigns, as well as the recent Hurricane Science and Severe Storm Sentinel (HS3) Earth Venture mission. Field campaigns provide for intensive observation of specific phenomena using a variety of instruments on aircraft, satellites and surface networks.

        GHRC also hosts a database of Atlantic and Pacific tropical storm tracks derived from the storm data published by the National Hurricane Center (NHC).
    • HS3 (2012-14)
      • Hurricane and Severe Storm Sentinel (HS3) is an Earth Ventures – Suborbital 1 mission aimed at better understanding the physical processes that control hurricane intensity change, addressing questions related to the roles of environmental conditions and internal storm structures to storm intensification.

        A variety of in-situ, satellite observations, airborne data, meteorological analyses, and simulation data were collected with missions over the Atlantic in August and September of three observation years (2012, 2013, 2014). These data are available at GHRC beginning in 2015.
    • GRIP (2010)
      • The Genesis and Rapid Intensification Processes (GRIP) experiment was a NASA Earth science field experiment in 2010 that was conducted to better understand how tropical storms form and develop into major hurricanes.

        The GRIP deployment was 15 August – 30 September 2010 with bases in Ft. Lauderdale, FL for the DC-8, at Houston, TX for the WB-57, and at NASA Dryden Flight Research Facility, CA for the Global Hawk.
    • TC4 (2007)
      • The NASA TC4 (Tropical Composition, Cloud and Climate Coupling) mission investigated the structure and properties of the chemical, dynamic, and physical processes in atmosphere of the tropical Eastern Pacific.

        TC4 was based in San Jose, Costa Rica during July 2007.

        The Real Time Mission Monitor provided simultaneous aircraft status for three aircraft during the TC4 experiment. During TC4, the NASA ER-2, WB-57 and DC-8 aircraft flew missions at various times. The science flights were scheduled between 17 July and 8 August 2007.
    • NAMMA (2006)
      • The NASA African Monsoon Multidisciplinary Analyses (NAMMA) campaign was a field research investigation based in the Cape Verde Islands, 350 miles off the coast of Senegal in west Africa.

        Commenced in August 2006, NASA scientists employed surface observation networks and aircraft to characterize the evolution and structure of African Easterly Waves (AEWs) and Mesoscale Convective Systems over continental western Africa, and their associated impacts on regional water and energy budgets.
    • TCSP (2005)
      • The Tropical Cloud Systems and Processes (TCSP) mission was an Earth science field research investigation focused on the study of the dynamics and thermodynamics of precipitating cloud systems and tropical cyclones. TCSP was conducted during the period July 1-27, 2005 out of the Juan Santamaria Airfield in San Jose, Costa Rica.

        The TCSP field experiment flew 12 NASA ER-2 science flights, including missions to Hurricanes Dennis and Emily, Tropical Storm Gert and an eastern Pacific mesoscale complex that may possibly have further developed into Tropical Storm Eugene.
    • ACES (2002)
      • The Altus Cumulus Electrification Study (ACES) was aimed at better understanding the causes and effects of electrical storms.

        Based at the Naval Air Station Key West in Florida, researchers in August 2002 chased down thunderstorms using an uninhabited aerial vehicle, or "UAV", allowing them to achieve dual goals of gathering weather data safely and testing new aircraft technology. This marked the first time a UAV was used to conduct lightning research.
    • CAMEX-4 (2001)
      • The Convection And Moisture EXperiment (CAMEX) was a series of NASA-sponsored hurricane science field research investigations. The fourth field campaign in the CAMEX series (CAMEX-4) was held in 16 August - 24 September, 2001 and was based out of Jacksonville Naval Air Station, Florida.

        CAMEX-4 was focused on the study of tropical cyclone (hurricane) development, tracking, intensification, and landfalling impacts using NASA-funded aircraft and surface remote sensing instrumentation.
    • CAMEX-3 (1998)
      • The Convection And Moisture EXperiment (CAMEX) is a series of hurricane science field research investigations sponsored by NASA. The third field campaign in the CAMEX series (CAMEX-3) was based at Patrick Air Force Base, Florida from 6 August - 23 September, 1998.

        CAMEX-3 successfully studied Hurricanes Bonnie, Danielle, Earl and Georges, yielding data on hurricane structure, dynamics, and motion. CAMEX-3 collected data for research in tropical cyclone development, tracking, intensification, and landfalling impacts using NASA-funded aircraft and surface remote sensing instrumentation.
    • GPM Ground Validation
      • The NASA Global Precipitation Measurement Mission (GPM) Ground Validation (GV) program includes the following field campaigns:

        a) LPVEx, Gulf of Finland in autumn 2010, to study rainfall in high latitude environments

        b) MC3E, cental Oklahoma spring and early summer 2011, to develop a complete characterization of convective cloud systems, precipitation and the environment

        c) GCPEx, Ontario, Canada winter of 2011-2012, direct and remove sensing observations, and coordinated model simulations of precipitating snow.

        d) IFloodS, Iowa, spring and early summer 2013, to study the relative roles of rainfall quantities and other factors in flood genesis.

        e) IPHEx, N. Carolina Appalachians/Piedmont region May-June 2014, for hydrologic validation over varied topography.

        f) OLYMPEx, Washington's Olympic Peninsula scheduled November 2015-February 2016, for hydrologic validation in extreme coastal and topographic gradients
    • OLYMPEX (Upcoming)
      • The OLYMPEX field campaign is scheduled to take place between November, 2015, and February, 2016, on the Olympic Peninsula in the Pacific Northwest of the United States.

        This field campaign will provide ground-based validation support of the Global Precipitation Measurement (GPM) satellite program that is a joint effort between NASA and JAXA.

        As for all GPM-GV campaigns, the GHRC will provide a collaboration portal to help investigators exchange planning information and to support collection of real-time data as well as mission science, project and instrument status reports during the campaign.
    • IPHEx (2014)
      • The Integrated Precipitation and Hydrology Experiment (IPHEx) was conducted in North Carolina during the months of April-June, 2014.

        IPHEx sought to characterize warm season orographic precipitation regimes, and the relationship between precipitation regimes and hydrologic processes in regions of complex terrain.
    • IFLOODs (2013)
      • The Iowa Flood Studies (IFloodS) experiment was conducted in the central to northeastern part of Iowa in Midwestern United States during the months of April-June, 2013.

        IFloodS' primary goal was to discern the relative roles of rainfall quantities such as rate and accumulation as compared to other factors (e.g. transport of water in the drainage network) in flood genesis.
    • GCPEX (2011-2012)
      • The GPM Cold-season Precipitation Experiment (GCPEx) occurred in Ontario, Canada during the winter season (Jan 15- Feb 26) of 2011-2012.

        GCPEx addressed shortcomings in GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. Collectively the GCPEx data set provides a high quality, physically-consistent and coherent data set suited to the development and testing of GPM snowfall retrieval algorithm physics.
    • MC3E (2011)
      • The Mid-latitude Continental Convective Clouds Experiment (MC3E) took place in central Oklahoma during the April–June 2011 period.

        The overarching goal was to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that had never before been available.
    • LPVEx (2010)
      • The Light Precipitation Evaluation Experiment (LPVEx) took place in the Gulf of Finland in September and October, 2010 and collected microphysical properties, associated remote sensing observations, and coordinated model simulations of high latitude precipitation systems to drive the evaluation and development of precipitation algorithms for current and future satellite platforms.

        In doing so, LPVEx sought to address the general lack of dedicated ground-validation datasets from the ongoing development of new or improved algorithms for detecting and quantifying high latitude rainfall
  • Projects
    • HS3 Suborbital Mission
      • Hurricane and Severe Storm Sentinel (HS3) is an Earth Ventures – Suborbital 1 mission aimed at better understanding the physical processes that control hurricane intensity change, addressing questions related to the roles of environmental conditions and internal storm structures to storm intensification.
      • DISCOVER was funded by NASA’s MEaSUREs program to provide highly accurate, multi-decadal geophysical products derived from satellite microwave sensors.
    • LIS Mission
      • Lightning observations from the Lightning Imaging Sensors (LIS) aboard the NASA’s TRMM satellite and International Space Station, as well as airborne observations and ground validation data.
    • SANDS
      • The SANDS project addressed Gulf of Mexico Alliance priority issues by generating enhanced imagery from MODIS and Landsat data to identify suspended sediment resulting from tropical cyclones. These tropical cyclones have significantly altered normal coastal processes and characteristics in the Gulf region through sediment disturbance.
      • The Land, Atmosphere Near real-time Capability for EOS (LANCE) system provides access to near real-time data (less than 3 hours from observation) from AIRS, AMSR2, MLS, MODIS, and OMI instruments. LANCE AMSR2 products are generated by the AMSR Science Investigator-led Processing System at the GHRC.
  • Resources
    • Tools & Technologies
      • A collection of tools & technologies developed and/or used by GHRC.
    • Publications
      • View GHRC & ITSC publications on the ITSC website
    • Innovations Lab
      • The GHRC Innovations Lab is a showcase for emerging geoinformatics technologies resulting from NASA-sponsored research at the University of Alabama in Huntsville.
    • Educational Resources
      • A list of resources from NASA, MSFC, and other sources for teachers and students focused on global change, hydrology, and science education.
    • Referencing our data
      • GHRC dataset citation help and examples.
    • Documents
      • Documentation related to GHRC datasets, software, and other offerings.
    • Glossary
      • Terms and their definitions
    • Featured items
      • The latest tools from GHRC.
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      • Local resources, lodging information, and weather to help you plan your visit to GHRC.
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      • A list to help you keep in touch with our personnel
    • FAQ
      • Frequently Asked Questions about GHRC data and services, and their answers.
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Guide Documents

Dataset PI Documents

Dataset Software

Advanced Microwave Sounding Unit Swath (AMSU-A)

Table of Contents

Advanced Microwave Sounding Unit Swath
AMSU Instrument Platforms
File Naming Convention
Data Format
Sample Read Routine
Links to other AMSU sites
Contact Information

Important Notices

NOAA-16 AMSU-A1 - Channel 4 out of spec performance confirmed on 4 March 2008. This channel is used for limb correction, and this failure requires GHRC to discontinue the AMSUA16 swath products. This dataset has an end date of 3 Mar 2008.

NOAA-17 AMSU-A1 suffered an instrument failure on October 28, 2003. As a result, AMSU-A channel-3 to channel-15 antenna temperatures are no longer available (AMSU-A channel-1 and channel-2 are working properly). NOAA-17 GHRC products end as of 28 Oct 2003.

Channel 14 on the NOAA-15 AMSU-A instrument stopped working in the Fall of 2000. In an effort to continue the channel 14 data set, we have developed an algorithm that estimates channel 14 measurements using data from AMSU-A channels 11, 12, and 13. The data currently being provided as "channel 14" is computed from this algorithm. This "channel 14" data is an educated estimate of what channel 14 would have measured had it remained operational.

Channel 11 on the NOAA-15 AMSU-A instrument has failed. Effective 25 Apr 2002, the limb correction equations have been modified to reflect an algorithm change for channels 8-14. Note that these corrections provide the 'best estimate' of what a fully functional instrument would provide.

Advanced Microwave Sounding Unit Swath

The Advanced Microwave Sounding Unit, (AMSU-A), is a cross-track, line-scanning instrument designed to measure scene radiances in 15 discrete frequency channels which permit the calculation of the vertical temperature and moisture profile from about 3 millibars (~45 km) to the Earth's surface. Each scan has 30 cells, with a resolution of 3.3 degrees (50 km at nadir). The swath width is 2343 km (96.66 degrees). The AMSU-A instrument is made up of two separate modules, A1 and A2. AMSU-A1 contains the 13 highest frequencies (50.3 - 89 GHz) of various polarizations. AMSU-A2 contains the two lowest frequency channels (23.8 and 31.4 GHz), both vertically polarized.

AMSU Instrument Platforms

AMSU flies on the National Oceanic and Atmospheric Administration (NOAA) polar orbiting spacecraft as part of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). Click here for more NPOESS information. An interesting orbital mechanics discussion is found here.

NOAA-15 was the first spacecraft to fly AMSU. Launched on 13 May 1998, NOAA-15 is in a sun synchronous near polar orbit. Flying at approximately 450 nautical miles (~833km) in altitude at an orbital inclination of 98.7 degrees, NOAA-15 completes an orbit every 101.2 minutes. The ascending equator crossing time is at approximately 1920 local time.

Launched on 21 September 2000, NOAA-16 is in a similar orbit, with an ascending equatorial crossing time near 1553 local time.

The Third Advanced Microwave Sounding Unit-A was launched on NOAA 17 on 24 June 2002 from Vandenberg AFB, California on a Titan II booster.

File Naming Convention

From 3 Aug 1998 through 31 May 1999, the AMSU-A Swath Data Product was packaged in HDF-EOS format, one file per day. Each daily file is then compressed using the UNIX 'gzip' command. The file may be uncompressed on a UNIX system, using the 'gunzip' command, or on a PC using the 'WinZip' program. The file naming convention was:



YYYY is the year (e.g., 1999)
JJJ is the day-of-year (e.g., 032)

NOTE: On 1 June 1999 (99.152), the file naming format was changed! The data prior to this date are available by special order only. Please contact User Services to order these preliminary data.

Data collected from 1 Jun 1999 forward have the following format. The Swath Data Products are packaged in HDF-EOS format, with one file per orbit. These daily files are tarred together using the UNIX tar command into a daily file that is then compressed using the UNIX 'gzip' command. The daily file is named:



SS is the platform identifier (e.g., 15 for NOAA-15)
YYYY is the year (e.g., 2000)
JJJ is the day-of-year (e.g., 235)
tar indicates UNIX 'tar'
gz indicates UNIX 'gzipped' (NOTE: this may be 'unzipped' using the UNIX 'gunzip' command, or on a Windows machine using the 'WinZip' program.)

Once a file is 'untarred' and 'unzipped' there will be individual orbit files which are named in the following manner:


SS is the platform identifier (e.g., 16 for NOAA-16)
YYYY is the year of start of orbit (e.g., 2001)
JJJ is the day-of-year of start of orbit (e.g., 045)
OOOOO is the orbit number (e.g., 09453)
SSSS is the start time of orbit, HHMM, UTC (e.g., 0901)
EEEE is the end time of orbit, HHMM, UTC (e.g.,1056)
GG is the ground station identifier (e.g., GC)

Data Format

HDF-EOS objects

For data from dates between 3 Aug 1998 and 31 May 1999, data are contained within a single HDF-EOS swath object named:


where YYYY and JJJ have the same meanings as above.

For Data from 1 June 1999 and later, data are contained in a single HDF-EOS swath object named:


where ddddd is the orbit number without leading zeroes (e.g. 2143, not 02143).


Two dimensions are defined:

Track - The along-track dimension or number of scans
Xtrack - The cross-track dimension (always 30)

Geolocation fields

Three geolocation fields are defined:


Contains latitude values in decimal degrees in the range -90.0 to 90.0, stored as an array of single-precision floating-point values (FLOAT32). The array is dimensioned "Track" by "Xtrack" ("C" order).


Contains longitude values in decimal degrees in the range -180.0 to 180.0, stored as an array of single-precision floating-point values (FLOAT32). The array is dimensioned "Track" by "Xtrack" ("C" order).


Contains International Atomic Time values in seconds with 1993-01-01 00:00:00 as the zero base (TAI93), stored as a vector of double-precision floating-point values (FLOAT64). The vector is dimensioned "Track".

Data fields

Fifteen data fields are defined, one per channel. Each data field contains single-precision floating-point values (FLOAT32) stored in an array that is dimensioned "Track" by "Xtrack" ("C" order). Each datum can therefore be geolocated using its row/column index to reference the values in the "Latitude" and "Longitude" geolocation fields. Each row can be temporally located by using its row index to reference the value in the "Time" geolocation field.

The data field names are representative of the channel data they contain, as follows:

Channel 1 23800.37 MHz
Channel 2 31400.42 MHz
Channel 3 50299.91 MHz
Channel 4 52799.39 MHz
Channel 5 53595.41 +- 115 MHz
Channel 6 54399.53 MHz
Channel 7 54940.64 MHz
Channel 8 55498.70 MHz
Channel 9 57290.33 MHz
Channel 10 57290.33 +- 217 MHz
Channel 11 57290.33 +- 322.2 +- 48 MHz*
Channel 12 57290.33 +- 322.2 +- 22 MHz
Channel 13 57290.33 +- 322.2 +- 10 MHz
Channel 14 57290.33 +- 322.2 +- 4.5 MHz*
Channel 15 88997.00 MHz

*NOTE: Channel 14 INOPERATIVE on NOAA-15 as of 30 Oct 2000
               Channel 11 INOPERATIVE on NOAA-15 as of 25 Apr 2002

Sample Read Routine

A sample read routine is shown here, or you may download the sample code, amsuareader.c. This routine must be compiled and linked with the HDF-EOS and HDF libraries.

Links to Other AMSU Sites

The GHRC Data Pool browse page at the Global Hydrology Resource Center contains AMSU-A global imagery.

From Colorado State Cooperative Institute for Research in the Atmosphere: CIRA's AMSU Website

Occasionally, orbit data is missed for technical reasons, or the satellite performs in a non-optimal manner. In these cases, NESDIS posts a NOAA Satellite Notice. These may be found at

For a history of all user notices, see

For the Office of Satellite Operations morning reports, see

Contact Information

To order these data or for further information, please contact:

Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932

Citing These data:

To help us best serve the scientific research communities, please cite GHRC data whenever you use them in a published paper or public presentation. We also request that you send us one reprint of any publication that cites our data. Please include the following information in each citation: principal investigators, year of data set release, data set title and version number, dates of the data you used, publisher, and digital media.

Example Citation:

Frank Wentz. 2010, near real-time. NRT AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures V11, May 1-15 2011. Huntsville, Alabama USA: AMSR-E SIPS at the GHRC DAAC. Digital media.

For further information please contact us at




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