Microwave Integrated Retrieval System (MiRS) and NOAA-20: Calibration/Validation and Science Developments One Year Post Launch

The Microwave Integrated Retrieval System (MiRS) is the official NOAA operational microwave-only satellite retrieval system. It currently processes passive microwave measurements from 10 different low earth orbit satellites, including ATMS data from the recently launched NOAA-20 satellite. The algorithm which is based on a one-dimensional variational approach uses the CRTM forward model to simulate radiances and to determine the atmospheric state which best fits the observed radiometric measurements, subject to other a priori constraints. The core 1DVAR retrieval consists of vertical profiles of atmospheric temperature, water vapor, non-precipitating clouds, precipitation size rain and ice particles, surface skin temperature and surface emissivity. Further post-processing is used to estimate, where appropriate, sea ice concentration and ice age, as well as snow water equivalent and snow grain size.

The NOAA-20 satellite was launched on 18 November 2017, and ATMS data were successfully processed through MiRS within hours of first reception at NOAA on 29 November 2017. Based on the strong initial validation results retrieval products were declared to have reached Beta maturity status at the same time. Additional validation results led to declaration of Provisional maturity for all retrieval products on 29 March 2018 meaning that users can generally treat retrievals with a high degree of confidence. Activities over the past year have been focused on continuing and broadening validation efforts both in terms of comparisons to independent references, as well as comparisons with retrievals from SNPP ATMS, which collects data in the same orbit with a one-half orbit (50 minute) lag. The presentation will focus on the results of extensive validation and assessment of temperature, water vapor, rainfall, and cryospheric products that have been underway for the approximately one year period since NOAA-20 launch. In particular, the longer time period allows examination of temporal stability of performance and identification of any seasonal dependence that may exist. Additional discussion will highlight efforts aimed at scientific and algorithmic improvements that have the potential for operational implementation.