The Rain Effect on Aquarius’ Sea Surface Salinity Retrieval
[26-Feb-2014] Tang, W., Yueh, S., Lagerloef, G., Fore, A., and Hayashi, A.
Presented at the 2014 Ocean Sciences Meeting
Rain has instantaneous impact on the sea surface salinity (SSS), but also interfere with the microwave remote sensing signals, making the task to retrieve SSS under rainy condition difficult. A rain correction scheme is developed based on analysis of the L-band radiometer/scatterometer residual signals after accounting for roughness due to wind and flat surface emissivity. The combined active passive (CAP) algorithm is used to retrieve SSS in parallel, with or without applying the rain correction scheme. Preliminary results indicate the rain correction consistently reduces global monthly RMS error in retrieved SSS in reference to Argo measurements by about 0.1 PSU. Biases are particularly reduced in regions with frequent precipitation such as the inter-tropical convergence zone (ITCZ), the far eastern Pacific fresh pool, the western Pacific warm pool and Indian Ocean. The rain effect on the seasonal SSS variability in these regions is examined to reveal its linkage with surface layer stratification.