MWR Smear Effect: A Counts-Level Empirical Correction and Possible Causes

The microwave radiometer (MWR) is a Dicke radiometer on board of the Aquarius (AQ)/SAC-D satellite. It was developed by Argentine space agency, Comisión Nacional De Actividades Espaciales (CONAE), and operates at 23.8 and 36.5 GHz frequencies. After MWR initially turned on, the first brightness temperature (TB) measurements were obtained, observing an anomalous recurrent effect when analyzing land/water crossings. The effect is present for all frequencies and earth incidence angles (EIAs) and results in a smearing of TB observations near strong contrast radiometric scenes. This paper summarizes the main features and discoveries around this anomaly leading to a general description of the problem: coupling of sequential MWR measurements. Consequently, an empirical correction algorithm is derived and validated. Also, possible causes are investigated.