Session
Weekend Session 2: Recent Launches - Research & Academia
Location
Utah State University, Logan, UT
Abstract
Launched in June 2021, the TROPICS Pathfinder CubeSat has a microwave radiometer payload sensitive to the frequencies for observing precipitation, humidity, temperature, and cloud ice. The observed brightness temperatures must be compared to a data set of ‘known’ quality to validate the measured data across all channels of the microwave radiometer. This research explores validating TROPICS Pathfinder data against reanalysis data to determine the quality of the provisional TROPICS Pathfinder data product, with an eye for the future of comparing against other microwave radiometer measurements. Validation involves comparing Pathfinder data to ERA5 reanalysis data by using the Community Radiative Transfer Model (CRTM) to calculate simulated radiances. The simulated radiances are then compared to the on-orbit Pathfinder data to determine biases, in a method known as single-differencing. The Pathfinder data presented here is at the provisional data maturity level and should be considered preliminary. This effort will be repeated when the TROPICS Pathfinder Level-1 radiances reach the validated data product maturity level late in the summer of 2022.
To effectively validate the Pathfinder mission, we have developed a process using MATLAB to read and match the TROPICS Pathfinder data for latitudes between -40° – 40° with desired data for comparison, which is ERA5 in this research. These latitude-longitude data match-ups are then filtered for data points without clouds, using cloud cover data from the GOES-16 satellite. Using data that is cloud-free and overocean ensures that single-differencing comparisons are made using like-data sets and will result in minimal error introduced by the reanalysis and radiative transfer models. After filtering the data, this validation process generates the input files required by CRTM to simulate the model, simulates these observations using the unique Pathfinder CRTM coefficients resulting in the most accurate data, and performs the necessary difference calculations. The end result is an automated process that performs data comparisons for researchers, and we present them as a summary for analysis. The provisional Level-1 radiances show good agreement with combined ERA5 and CRTM simulated radiances, and we expect even better agreement with the upcoming validated Level-1 radiances.
Data Validation of the NASA Time-Resolved Observations of Precipitation Structure and Storm Intensity with a Constellation of Smallsats (TROPICS) Pathfinder Microwave Radiometer
Utah State University, Logan, UT
Launched in June 2021, the TROPICS Pathfinder CubeSat has a microwave radiometer payload sensitive to the frequencies for observing precipitation, humidity, temperature, and cloud ice. The observed brightness temperatures must be compared to a data set of ‘known’ quality to validate the measured data across all channels of the microwave radiometer. This research explores validating TROPICS Pathfinder data against reanalysis data to determine the quality of the provisional TROPICS Pathfinder data product, with an eye for the future of comparing against other microwave radiometer measurements. Validation involves comparing Pathfinder data to ERA5 reanalysis data by using the Community Radiative Transfer Model (CRTM) to calculate simulated radiances. The simulated radiances are then compared to the on-orbit Pathfinder data to determine biases, in a method known as single-differencing. The Pathfinder data presented here is at the provisional data maturity level and should be considered preliminary. This effort will be repeated when the TROPICS Pathfinder Level-1 radiances reach the validated data product maturity level late in the summer of 2022.
To effectively validate the Pathfinder mission, we have developed a process using MATLAB to read and match the TROPICS Pathfinder data for latitudes between -40° – 40° with desired data for comparison, which is ERA5 in this research. These latitude-longitude data match-ups are then filtered for data points without clouds, using cloud cover data from the GOES-16 satellite. Using data that is cloud-free and overocean ensures that single-differencing comparisons are made using like-data sets and will result in minimal error introduced by the reanalysis and radiative transfer models. After filtering the data, this validation process generates the input files required by CRTM to simulate the model, simulates these observations using the unique Pathfinder CRTM coefficients resulting in the most accurate data, and performs the necessary difference calculations. The end result is an automated process that performs data comparisons for researchers, and we present them as a summary for analysis. The provisional Level-1 radiances show good agreement with combined ERA5 and CRTM simulated radiances, and we expect even better agreement with the upcoming validated Level-1 radiances.
