The Quantifying, Predicting, and Exploiting Uncertainty Program : exploring oceanographic processes in a complex bathymetric shelf/slope environment affected by the Kuroshio

Abstract

We will describe the multi-disciplinary international program, Quantifying, Predicting and Exploiting Uncertainty, which consisted of observations, modeling and remote sensing studies focused on a region northeast of Taiwan in the East China Sea. We focus on results on the physical oceanographic and biogeochemical processes. Concurrent observations of acoustic propagation also occurred during the intensive observation period. This program was a joint Taiwan-U.S. effort involving four different ships sampling the continental shelf and slope during August-September, 2009. Primary goals of the program included 1) studying the structure and variability of the Cold Dome, a cool cyclonic feature frequently present in summer over the continental shelf; 2) examining the strength of upwelling from the continental slope to the shelf and the associated biogeochemical fluxes; and 3) establishing the predictability and structure of Kuroshio Intrusions onto the continental shelf. In addition, the program examined the characteristics of internal tides and waves in this region. During the intensive observations in Aug.-Sept., 2009, the continental shelf was strongly impacted by the passage of Typhoon Morakot across the region. Due to heavy rainfall throughout southern Taiwan, fresh water plumes impacted the continental shelf for several weeks after the typhoon. Numerical modeling studies show a pronounced cooling of 3°C after the storm, which are associated with significant fluxes of nitrate and phosphate onto the continental shelf. Both internal tides over the continental slope, as well as internal waves over the shelf and slope are characterized and compared with recent observations in other regions including the South China Sea and the northeastern U.S. off New Jersey. A particularly striking aspect of this region is the profusion of potential internal wave generation sites due to the presence of three different canyons with complex and steep bathymetry.