An overview of the Impact of Typhoons on the Ocean in the Pacific (ITOP) field program during August – October 2010

The Impact of Typhoons on the Ocean in the Pacific (ITOP) field campaign was conducted over the western North Pacific during August – October 2010. The primary science objectives addressed ocean and atmosphere factors in the tropical cyclone environment. A primary objective was to examine the formation and evolution of the cold wake induced by a tropical cyclone. Important factors examined include the influence of pre-existing ocean eddies and tide and the structure of the atmospheric boundary layer. A second objective was to examine the characteristics of air-sea fluxes for winds greater than 30 m s-1. A third objective was to examine the impact of the ocean on typhoon intensity.

The observation platforms consisted to two USAF WC-130J aircraft from the 53rd Weather Reconnaissance Squadron (Hurricane Hunters), the DOTSTAR aircraft from Taiwan, and the R/V Revelle. Specific observation types included dropwindsondes, AXBTs, ocean drifters, and ocean floats. The WC-130J aircraft deployed all of these and the DOTSTAR aircraft also deployed dropwindsondes. A moored buoy array that was pre-positioned to the northeast of Luzon, Philippines was also utilized along with additional moored buoys that were positioned by ship prior to the start of the experiment.

During ITOP, the aircraft observed three major typhoons. During Typhoon Fanapi and TY Megi, two sets of ocean floats were air-deployed immediately ahead of each storm path. Then, the aircraft obtained additional observations as each storm passed over the array of ocean instruments. The R/V Revelle then observed the ocean environment following the passage of each storm to examine the evolution of the surface and subsurface cold wake structures.

The observational component of ITOP was complemented by a quite of atmosphere, ocean, and couple modeling efforts by several operational and research modeling groups. Also, full complements of satellite-based products were utilized during the field program.

In this presentation, the ITOP experiment observations and scenarios will be summarized to provide examples of the data collection efforts, the scope of the observational data, and potential studies of the air-ocean environment in a tropical cyclone over the western North Pacific.