Initial Observing System Experiments with All-Sky Radiances from the TROPICS Constellation Using HAFS

The Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) NASA Earth Venture mission successfully launched four satellites into low-Earth orbit in May 2023. This constellation, along with the additional TROPICS Pathfinder satellite that was launched into sun-synchronous orbit in June 2021, provides rapid-refresh microwave observations to capture the synoptic-scale and mesoscale thermodynamic and precipitation structure of tropical cyclones (TCs). Each of these Micro-sized Microwave Atmospheric Satellite (MicroMAS-2) CubeSats is equipped with a 12-channel microwave radiometer targeting wavelengths sensitive to temperature, moisture, precipitation, and cloud ice (Blackwell et al. 2018).

In a previous observing system experiment (OSE) conducted using TROPICS Pathfinder from Sam (2021), assimilating TROPICS all-sky radiances led to improvements in the low-level wind structure in the analysis and forecast in NOAA’s FV3-based Hurricane Analysis and Forecast System (HAFS). Building on that work, this study will take a first look at assimilating all-sky radiances from the full complement of TROPICS satellites for a case from the 2023 Atlantic hurricane season. TROPICS radiances will be compared with observations from other platforms and assimilated into HAFS using the all-sky observation error approach described in Christophersen et al. (2021) to assess their impact on the TC analysis and forecast.