Can Current Hyperspectral Infrared Sounders Capture the Small Scale Atmospheric Water Vapor Spatial Variations?

Severe storms are often associated with high temporal and spatial variations in atmospheric moisture deviation. Satellite-based hyperspectral IR sounders are widely used for weather forecasting and data assimilation in numerical weather prediction. Current infrared (IR) sounders have spatial resolutions ranging from 12 to 16 km, with future sounders improved to 4-8 km. It is important to understand if measurements from the current and future IR sounders can capture small-scale atmospheric moisture variations, especially during mesoscale weather events. Using measurements from three Advanced Himawari Imager moisture absorption bands, different sounder resolutions are simulated for sub-footprint moisture variation analysis. Current sounders are limited when attempting to capture small-scale moisture variations, especially over land and in the pre-convection environment. In contrast, future sounders such as the InfraRed Sounder with 4 km resolution can better capture such small-scale variations. In addition, the higher spatial resolution IR sounders provide more clear sky observations for applications.