Advanced Microwave Scanning Radiometer for EOS

Advanced Microwave Scanning Radiometer for EOS
Name	Advanced Microwave Scanning Radiometer for EOS
Mission	Earth Observing System
Operator	National Aeronautics and Space Administration (NASA)
Manufacturer	Jet Propulsion Laboratory (JPL)
Launch	Tropical Rainfall Measuring Mission?
Type	Microwave radiometer

Advanced Microwave Scanning Radiometer for EOS The Advanced Microwave Scanning Radiometer for EOS (AMSR-E) was a spaceborne passive microwave radiometer developed for the Earth Observing System era to measure global hydrological and cryospheric parameters. It flew as a key instrument on the Aqua mission and provided data used by agencies such as the National Oceanic and Atmospheric Administration (NOAA), the Japan Aerospace Exploration Agency (JAXA), and research institutions including California Institute of Technology (Caltech) and University of Colorado Boulder.

Overview

AMSR-E was conceived in collaboration between NASA and JAXA during programmatic planning in the 1990s involving meetings at Goddard Space Flight Center and Jet Propulsion Laboratory. The instrument complemented contemporaneous sensors like the Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Microwave Scanning Radiometer 2 (AMSR2), the Special Sensor Microwave/Imager (SSM/I), and the Tropical Rainfall Measuring Mission (TRMM) instruments by offering high-sensitivity microwave brightness temperatures across multiple frequencies. Project management involved participants from University of Maryland, College Park, Columbia University, Massachusetts Institute of Technology (MIT), and international partners at National Institute of Information and Communications Technology (NICT).

Instrument Design and Specifications

The AMSR-E instrument architecture included a rotating reflector antenna, passive radiometer channels, cryogenic receivers, and radiometric calibration targets. The design drew on prior heritage from Special Sensor Microwave Imager Sounder and engineering from Honeywell International Incorporated contractors working with Lockheed Martin. Key specifications included multiple frequency channels near 6.9 GHz, 10.7 GHz, 18.7 GHz, 23.8 GHz, 36.5 GHz, and 89.0 GHz, each with dual-polarization capability and swath width enabling near-global coverage comparable to MetOp instruments. The instrument mass, thermal control, and power budgets were reviewed in panels including representatives from European Space Agency (ESA), Canadian Space Agency (CSA), and Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO).

Science Objectives and Applications

AMSR-E's primary objectives targeted retrievals of sea surface temperature, sea ice concentration, snow water equivalent, soil moisture, precipitation rate, and atmospheric water vapor. Science teams at National Snow and Ice Data Center (NSIDC), Plymouth Marine Laboratory, Scripps Institution of Oceanography, Woods Hole Oceanographic Institution (WHOI), and Lamont–Doherty Earth Observatory exploited AMSR-E for climate studies, observing phenomena such as the El Niño–Southern Oscillation, Arctic amplification, Antarctic Peninsula ice dynamics, and regional droughts impacting areas including Sahel and Amazon Rainforest. Applications extended to operational services at NOAA National Centers for Environmental Prediction (NCEP), Japan Meteorological Agency (JMA), and flood forecasting centers in partnership with United Nations Office for Disaster Risk Reduction.

Calibration and Data Processing

Calibration strategies used onboard cold sky views and internal noise diodes plus vicarious calibration involving sites like White Sands Missile Range and cross-calibration with WindSat and Aqua MODIS products. Data processing pipelines ran at facilities including Goddard Space Flight Center and the JPL Physical Oceanography Distributed Active Archive Center (PO.DAAC). Algorithms incorporated radiative transfer models developed at NOAA/NESDIS, emissivity databases from NASA Langley Research Center, and inversion schemes refined by groups at University of Bremen and University of Tokyo. Quality control employed matchup analyses with in situ networks such as Global Precipitation Climatology Project (GPCP) gauges, Argo floats, and Surface Radiation Budget stations.

Mission History and Flight Operations

AMSR-E was launched aboard Aqua during the broader Earth Observing System program alongside instruments like CERES, MODIS, and AIRS. Flight operations were coordinated by NASA Goddard Space Flight Center with routine contacts involving Mission Control Center personnel, and anomaly response leveraged expertise at JPL and Goddard. The mission timeline included commissioning phases, operational steady-state, and contingency operations following instrument anomalies; teams from JAXA and university partners executed recovery and extended-mission planning. Data policy discussions involved stakeholders from U.S. Geological Survey (USGS), European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and research consortia.

Performance and Validation Studies

Validation campaigns compared AMSR-E retrievals with field campaigns like SnowEx, GLOBALRAIN, and coordinated airborne measurements from NASA ER-2 and DC-8 platforms. Peer-reviewed assessments were published by researchers at University of Washington, Imperial College London, ETH Zurich, and National Center for Atmospheric Research (NCAR). Studies quantified instrument radiometric stability, channel noise-equivalent delta temperature, and biases relative to in situ buoy networks maintained by NOAA Pacific Marine Environmental Laboratory and National Data Buoy Center (NDBC). Comparative analyses with successor instruments such as AMSR2 and GPM Microwave Imager informed algorithm refinements led by International Precipitation Working Group.

Data Products and Accessibility

AMSR-E delivered Level-1 calibrated brightness temperatures and Level-2 geophysical retrievals (sea ice, soil moisture, precipitation) distributed through PO.DAAC, NSIDC DAAC, and national data portals. Data formats adhered to standards advocated by Committee on Earth Observation Satellites (CEOS), with metadata conventions aligned with CF (netCDF) Conventions promoted by the Open Geospatial Consortium (OGC and ISO standards bodies). Accessibility for researchers and operational users was enhanced via mirror services at JAXA Earth Observation Research Center and portals run by European Space Agency and academic data centers at University of Colorado Boulder and University of Maryland. Licensing and attribution practices followed guidelines from NASA Earth Science Data Systems.

Category:Earth observation satellites Category:Microwave radiometers Category:NASA instruments