Aquarius SSS Measurements in Rain: Science or Errors?
[26-Feb-2014] Jacob, M.M., Ebrahimi, H., Santos-Garcia, A., Jones, W.L., and Asher, W.
Presented at the 2014 Ocean Sciences Meeting
After analyzing over two years of Sea Surface Salinity (SSS) data from Aquarius (AQ), it is observed that the spatial patterns of delta-SSS (differences between the Hybrid Coordinate Ocean Model (HYCOM) and AQ measurements) can often be associated with rainfall events. This begs the question "Is it science (sea water freshening) or AQ retrieval errors?" This paper examines this question and presents several hypotheses that are compared with empirical SSS observations. For example, we describe electromagnetic models that predict ocean surface brightness effects caused by: instantaneous roughening by rain (Splash Effect) and impedance matching by a surface rain layer (ponds) over sea water. We present comparisons of delta-SSS with a new collocated AQ Rain Accumulation Product that provides the rainfall history for each IFOV during the previous 24 hrs to the observation time. These rainfall accumulation time histories are used with an empirical transient near-surface SSS profile model developed by Applied Physics Laboratory (APL) at University of Washington to examine possible rain freshening effects.