Evaluation of Precipitation and TPW Retrieval based on MiRS SNPP/ATMS Reprocessed Data during 2012-present

Since its launch on October 28, 2011, the Advanced Technology Microwave Sounder (ATMS) instrument onboard the SNPP (Suomi National Polar-Orbiting Partnership) has exceeded its seven-year design life, and continues providing valuable observational radiance data that exceed all performance requirements. This provides an unprecedented opportunity to evaluate the NOAA Microwave Integrated Retrieval System (MiRS) performance from a climatological perspective based on a single instrument and satellite. MiRS is a physical retrieval system that was developed and is currently operational run at NOAA supporting over 15 space-borne microwave sensors onboard various platforms.

NOAA and the Cooperative Institute for Satellite Earth System Studies (CISESS), University of Maryland, have been collaboratively reprocessing MiRS retrievals based on SNPP ATMS observations for the period of 2012-2020. The reprocessing project aims to solve inconsistencies of input data and ATMS L1 calibration as well as MiRS version changes to provide high quality data to the scientific community and downstream algorithms. For example, the NASA Water Vapor Project-MEaSUREs (NVAP-M), which is designed to provide the most stable water vapor dataset over time for use in climate applications, can benefit from this effort. The ATMS Level 1 recalibrated brightness temperature measurements were based on the calibration algorithm that was operational since October 15, 2019. The MiRS version used in reprocessing is V11R8.

This study focuses on the long period time series and climatological evaluation of the reprocessed products of precipitation and TPW (Total Precipitable Water) from 2012-present. Regional precipitation evaluations will be performed over the areas with available ground-based observational data, namely the Continental U.S. (CONUS), Asia, and Europe. Over the CONUS, the Multi-Radar/Multi-Sensor System (MRMS) will be used as a reference for precipitation. Over Asia, the AERA5-Asia (Asian Precipitation-Highly Resolved Observational Data Integration Toward Evaluation of Water Resources European Centre for Medium-Range Weather Forecasts Reanalysis 5-Land) dataset will be used. Over Europe, the European Climatological high-resolution gauge-adjusted radar precipitation dataset (EURADCLIM) will be used. All of the three datasets include ground-based radar and rain gauge observations. Global inter-comparison will be performed against the Global Precipitation Climatology Project (GPCP) data sets and we will evaluate how well the single-orbiter can represent the multi-year climatology.

An ongoing effort at the Cooperative Institute for Research in the Atmosphere (CIRA) is to reprocess and extend NVAP-M to a 40-year period of 1988-2027 to provide reliable global water vapor data for a wide variety of weather and climate applications. MiRS ATMS retrievals provide one of the core data inputs to NVAP-M. By taking advantage of the consistently reprocessed data, this study will also perform TPW time series analyses from a climatological point of view.