Intraseasonal Sea Surface Salinity Variations in the Northeastern Tropical Pacific Fresh Pool
[18-Nov-2015] Lee, T., Hasson, A., Bingham, F., Farrar, T., and Boutin, J.
Presented at the 2015 Aquarius/SAC-D Science Team Meeting
NASA field campaign SPURS-2, slated to take place in the Northeastern Tropical Pacific Fresh Pool, aims to improve the understanding of salinity processes in that region associated with high precipitation and active ocean dynamics. Satellite SSS from Aquarius and SMOS provide large-scale context to understand salinity processes in the region, which will complement the in-situ observations to be collected during SPURS-2. As part of the effort in preparation for SPURS-2, we examine the dominant temporal and spatial scales of SSS around 10ÂºN and 125ÂºW using Aquarius and SMOS SSS measurements together with the output from a 18-km resolution ocean circulation model. A wave-frequency spectrum analysis of SSS reveals a dominant time scale of 50-150 days and spatial scale of 8-20 degrees of longitude during the period of 2011 to 2014. This intraseasonal SSS signal shows a westward propagating tendency of about 17 cm/s. Observed and modeled sea surface height and temperature also exhibit similar propagating characteristics as the SSS. The nature of the observed propagating signal is examined by analyzing the effects of horizontal advection associated with the equatorial current system, Ekman pumping, and precipitation.