Infrared Sounding of the Boundary Layer: Moving beyond the Program of Record

The 2017 Earth Science Decadal Survey describes two general types of measurements: those from current or planned instruments (the Program of Record, or POR), and those from future innovative technologies. Infrared sounding has a very detailed POR, with five infrared atmospheric sounders currently operating. These include the Atmospheric Infrared Sounder on the Aqua spacecraft, the two Crosstrack Infrared Sounder (on JPSS1 and SNPP) and two Infrared Atmospheric Sounding Interferometer on (on METOP-A and METOP-B). These instruments have had high impact on operational forecasts, despite clouds limiting the forecast use of infrared information to mostly clear areas or the upper troposphere above clouds. This success has ensured international commitment to operating hyperspectral infrared sounders, and supporting their continued POR, through at least the 2030s. However, these instruments will have nominal spatial resolution comparable to current sounders. As global and regional weather forecast models move to spatial resolution finer than about 10 km, a need for information about processes at the smallest scales necessitates finer spatial resolution observations. We will discuss the operational, applications, and science research requirements of possible future IR sounders, and how they help meet the 2017 NRC Decadal Survey need for improved understanding of the boundary layer. We will also describe instrument concepts developed at JPL for next-generation infrared sounders. Finally, we will identify challenges with future high spatial resolution sounders in technology, measurement approach, retrievals, and integration with the POR.