Retrieving atmospheric pressure with airborne or spaceborne radar: Design considerations of V-band differential absorption radar

Atmospheric surface pressure and pressure profiles are essential variables in weather modeling and forecasting. Pressure gradients generate atmospheric motion and are essential to the air-sea heat exchange feedbacks within the planetary boundary layer (PBL) that lead to convective storms and heavy precipitation. Despite the importance of atmospheric pressure, current technology of pressure observations relies almost entirely on buoy measurements over the majority of the ocean. These measurements are too sparse to capture pressure gradients of even synoptic scale events, and leave models starved of the dynamic information.

NASA/Goddard Space Flight Center (GSFC), NASA/Langley Research Center (LaRC), Tomorrow.io, and Morgan State University are developing the Microwave Barometric Radar and Sounder (MBARS), an airborne sensor to retrieve atmospheric surface pressure and vertical pressure profiles. MBARS is a new combined active/passive microwave instrument in the O2 absorption V-band (64-70 GHz) funded by the NASA Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP). The long-term objective of this project is to improve our understanding of the atmospheric state by enabling global satellite-based monitoring of atmospheric pressure over oceans.

Pressure retrievals impose unique challenges for atmospheric radar, including precision, stability, bandwidth, and linearity requirements beyond typical systems. This presentation will discuss instrument performance considerations to enable pressure retrievals with differential absorption radar (DAR) and microwave radiometry, as well as implications for potential spaceborne instruments in the future.