Evaluating the Impact of the GeoXO Imager's 5.15 µm Band on Moisture Detection

A 5.15 µm band on the future GeoXO Imager (GXI) will complement the legacy set of channels on the current GOES-R Advanced Baseline Imagery (ABI). The 5.15 µm band will observe the short wavelength side of the water vapor absorption band (5-8 µm), providing detection of low-level water vapor where higher moisture conditions are a precursor for convective initiation. The Weather Research and Forecasting (WRF) model is used to simulate a case study of a high precipitation event on 25 July 2022, qualitatively illustrating the use of the 5.15 µm band in observing low-level moisture in scenes with high total precipitable water (TPW).

To quantify the benefits of adding the 5.15 µm band we perform information content analysis in both clear-sky and cloudy scenes. The preliminary results show that clouds reduce the information content, but less significantly with the 5.15 µm band added. In addition, a neural network retrieval model is developed based on simulated radiances from the July 2022 case study period. The retrieval is trained and performed with 10 infrared channels, including the 5.15 µm band, and then repeated without the 5.15 µm band. The results are compared to understand how the 5.15 µm band can improve estimates of moisture profiles, TPW, and Convective Available Potential Energy (CAPE). Ultimately, the RMSE and biases in both clear and cloudy scenes, as well as in a variety of dry to wet moisture profiles, are used to characterize the value of 5.15 µm band.