Satellite passive microwave sensors observe microwave radiation traveling upward from the Earth. The sensors can see through most clouds and collect measurements both day and night, which is especially useful in high latitudes during the long polar night. Available since 1978, scientists have used passive microwave measurements to derive significant and meaningful climate records of many parameters, including the dramatic decline in Arctic sea ice.
Currently available gridded passive microwave data sets serve a diverse community of hundreds of data users, but do not meet many requirements of modern climate data records, most notably in the areas of intersensor calibration and consistent processing methods. The original gridding techniques were relatively primitive and were produced on 25 km grids using the original EASE-Grid definition that is not easily accommodated in modern software packages.
This effort is funded by NASA's Making Earth System Data Records for Use in Research Environments (MEaSUREs) to reprocess the historical gridded data sets as Earth System Data Records (ESDRs),using the most mature available Level 2 satellite passive microwave (Scanning Multichannel Microwave Radiometer [SMMR], Special Sensor Microwave Imager [SSM/I] -S pecial Sensor Microwave Imager/Sounder [SSMIS], Advanced Microwave Scanning Radiometer - EOS [AMSR-E]) records from 1978 to the present, and using state-of-the-art numerical methods to increase image spatial resolution. We expect the new processing methods to enable scientists to better analyze trends in coastal regions and marginal ice zones that were not possible with previous releases of the data.
The new data use the EASE-Grid 2.0 definition and netCDF-CF formatting, which allows users to extract compliant geotiff images, and provides for easy importing and correct reprojection interoperability in many standard packages, including Interactive Data Language [IDL], ENVI, Geospatial Data Abstraction Library (GDAL), Panoply and Arc tools. As a consistently-processed, high-quality satellite passive microwave ESDR, we expect this data set to supercede at least 4 of NSIDC DAAC's standard EASE-Grid passive microwave products, and pave the way for new insights from higher-resolution derived geophysical products.