Advanced Technology Microwave Sounder

Advanced Technology Microwave Sounder
Name	Advanced Technology Microwave Sounder
Type	Satellite radiometer
Operator	National Aeronautics and Space Administration / European Space Agency
Country	United States
Launched	Multiple missions
Wavelength	Microwave
Status	Operational / Experimental

Advanced Technology Microwave Sounder

The Advanced Technology Microwave Sounder is a spaceborne microwave radiometer family developed to measure atmospheric temperature, humidity, and surface properties from low Earth orbit. It informs weather forecasting by providing radiometric sounding across microwave bands, supporting climate research, and complementing infrared instruments on Earth observation satellites.

Overview and Purpose

The Advanced Technology Microwave Sounder was designed to deliver vertical profiles of atmospheric thermodynamic variables for numerical weather prediction centers such as European Centre for Medium-Range Weather Forecasts, National Weather Service, Met Office, Japan Meteorological Agency, and Canadian Meteorological Centre. It builds on heritage from Microwave Sounding Unit, Advanced Microwave Sounding Unit, and Cross-track Infrared Sounder efforts, aiming to augment missions like NOAA-20, Suomi NPP, MetOp, JASON-3, and collaborations with National Oceanic and Atmospheric Administration. The instrument supports international programs including Global Climate Observing System, World Meteorological Organization, Committee on Earth Observation Satellites, and partnerships with European Organisation for the Exploitation of Meteorological Satellites and China National Space Administration.

Design and Instrumentation

The instrument architecture integrates radiometric channels in oxygen and water vapor absorption bands with synthetic aperture and scanning techniques developed alongside teams from Jet Propulsion Laboratory, Lockheed Martin, Ball Aerospace, Honeywell, and Raytheon. Key subsystems trace lineage to designs by Harvard-Smithsonian Center for Astrophysics microwave labs, with cryogenic front ends influenced by research at Massachusetts Institute of Technology and California Institute of Technology. Electronics and processors incorporate flight heritage from Harris Corporation and Thales Alenia Space. Antenna designs reference work by NASA Goddard Space Flight Center and European Space Research and Technology Centre. Signal chains employ calibration loads, radiometric detectors, and digital backends consistent with standards used on Aqua, Aura, Terra, and Envisat missions.

Calibration and Data Processing

Calibration strategies combine onboard hot-load and cold-sky references refined through techniques pioneered at National Institute of Standards and Technology and validated in campaigns with NOAA National Centers for Environmental Prediction and European Space Agency calibration facilities. Data processing pipelines are implemented by teams at National Centers for Environmental Prediction, Met Office Hadley Centre, NASA Goddard, European Centre for Medium-Range Weather Forecasts, and Japan Aerospace Exploration Agency to produce level-0 through level-3 products compatible with data assimilation systems used by Global Forecast System, Integrated Forecast System, Model for Interdisciplinary Research on Climate, and Copernicus Climate Change Service. Intercalibration efforts reference sensor records from Special Sensor Microwave/Imager, Tropical Rainfall Measuring Mission, and GPM datasets.

Flight and Satellite Platforms

Flights have been mounted on polar-orbiting platforms including systems built by Ball Aerospace, Lockheed Martin, and Airbus Defence and Space for agencies such as NOAA, NASA, ESA, JAXA, ISRO, and CNSA. The sounder has been integrated on satellites in sun-synchronous and afternoon constellation slots coordinated through International Charter on Space and Major Disasters and operational constellations like MetOp-SG and JPSS. Launch vehicles and campaigns have involved providers including SpaceX, United Launch Alliance, Arianespace, Roscosmos, and ISRO launchers, with mission operations supported by ground segments at EUMETSAT, NOAA Satellite and Information Service, JAXA Earth Observation Research Center, and Indian Space Research Organisation facilities.

Applications and Scientific Impact

Products from the sounder are used by forecasting centers such as European Centre for Medium-Range Weather Forecasts and NOAA National Weather Service to improve short- and medium-range forecasts for phenomena monitored by National Hurricane Center, Joint Typhoon Warning Center, Met Office, and disaster response agencies including Federal Emergency Management Agency. Climate research groups at NASA Jet Propulsion Laboratory, Potsdam Institute for Climate Impact Research, Hadley Centre, and Max Planck Institute for Meteorology use records to study trends alongside datasets from GODDARD Institute for Space Studies, International Panel on Climate Change, World Climate Research Programme, and Climate Prediction Center. Hydrology teams at USGS, Australian Bureau of Meteorology, and China Meteorological Administration exploit moisture retrievals in combination with outputs from GRACE and SMAP missions to monitor floods, droughts, and cryosphere changes investigated by National Snow and Ice Data Center and Alfred Wegener Institute.

Performance, Validation, and Limitations

Validation campaigns involve coordinated field experiments led by National Oceanic and Atmospheric Administration, European Space Agency, NASA Langley Research Center, NOAA Earth System Research Laboratories, and university groups at University of Colorado Boulder, Massachusetts Institute of Technology, University of Oxford, and Imperial College London. Intercomparison exercises use reference radiosonde networks such as Global Climate Observing System radiosonde archives and buoy networks maintained by National Data Buoy Center and Global Drifter Program. Limitations include sensitivity to surface emissivity variations over regions studied by USGS, complications in polar regions analyzed by Scott Polar Research Institute and Polar Research Institute of China, and radio-frequency interference monitored by International Telecommunication Union. Continuous improvements draw on community efforts from Committee on Earth Observation Satellites, World Meteorological Organization, Group on Earth Observations, and academic consortia at UCAR and NOAA Cooperative Institute for Research in Environmental Sciences.

Category:Remote sensing instruments