TEMPEST-D and GPM-GMI Observations Over Precipitating Systems: A Cross-Validation Study

The objective of this study is to cross-validate observations over precipitating systems by microwave radiometers on the temporal experiment for storms and tropical systems demonstration (TEMPEST-D) CubeSat mission and the global precipitation measurement microwave imager (GMI). The purpose of this article is twofold: first, to show consistency between TEMPEST-D and GMI observations, and second, to demonstrate the potential to enhance temporal sampling when TEMPEST-D and GMI observations are merged. Two cross-validation methodologies were employed. The first cross-validation methodology is to quantitatively compare TEMPEST-D and GMI brightness temperature (TB) observations over precipitation systems using a priori spatiotemporal constraints. The comparative analysis showed that the two instruments' TB observations have similar probability distributions, with a mean absolute difference of 2.9 K. The second cross-validation methodology is to quantitatively compare TEMPEST-D and GMI TB observations over tropical cyclone systems. Three storm cases were analyzed in this comparative study. The analysis showed that the structure and intensity of the storms are similar in TEMPEST-D and GMI TB observations, and the overall average correlation coefficient (r) is 0.9. Combining TEMPEST-D and GMI TB observations over the hurricane systems increased the sampling frequency by a factor of 2.5, compared to using the GMI data alone.