Reising Steve (Colorado State University, USA); Bosch Xavi (Colorado State University, USA); Kangaslahti Pekka (Jet Propulsion Lab, USA)

This talk presents an analysis of the wet path delay spectrum from high-resolution airborne measurements with the HAMMR microwave radiometer. Knowledge of the path delay spectrum is important for SWOT, particuarly at high spatial frequencies, below the SWOT radiometer spatial resolution. Currently, the spectrum at high frequencies is extrapolated from ~25km resolution satellite measurements. With the HAMMR system, the spectra are measured to 150m. This system includes a scanning version of the Advanced Microwave Radiometer flying on Jason-2 and -3 as well as high frequency channels from 90-183 GHz. Flights were conducted in November 2014 along the west coast of the United States and over some inland rivers and lakes. This talk will describe the instrument and the calibration applied to the radiometer. It will also discuss the path delay retrieval algorithm that was developed for the sensor. During the campaign, observations were made in both clear and cloudy conditions and spectrum will be shown for both cases. Finally, a comparison will be made to the extrpolated spectrum currently used in the SWOT error budget.