The 2018 PISTON Field Campaign: Science, Description and Early Results

The Boreal Summer Intraseasonal Oscillation (BSISO) strongly modulates atmospheric circulation patterns, rainfall and the diurnal cycle over the waters of the W. Pacific and South China Sea. The BSISO is associated with active and break periods of the Asian Monsoon system, and has significant teleconnections to higher latitudes, as well as impacting tropical cyclones in the region. Timing, structure and propagation of the BSISO are poorly simulated in weather forecasting and climate models. PISTON (Propagation of Intraseasonal Tropical Oscillations) is a major field/modeling campaign to improve understanding of the BSISO, including atmospheric and ocean responses, ocean-atmosphere coupling and air-sea interaction. PISTON field observations targeted early August to mid-October 2018 in the western Pacific north of Palau with additional observations planned for boreal summer 2019 west of Luzon, Philippines. The primary platform for the PISTON 2018 campaign is the R/V Thomas G. Thompson operated by the University of Washington. Field observations include measurements of:

- convection by the Colorado State University's SEA-POL C-band Doppler, polarimetric radar;

- The thermodynamic state of the atmosphere via continuous 3 hourly radiosonde launches (CSU).

- surface fluxes by NOAA's Earth Systems Research Lab

- aerosol backscatter and tenuous cloud layers using high spectral resolution Lidar observations operated by the U. of Wisconsin

- upper ocean structure and turbulence by Oregon State University

as well as

- long term (1 year) upper ocean responses using two moorings deployed by Scripps Institution of Oceanography, and

- the spatial structure of the upper ocean using underway CTD (Scripps)

- deployment of SOLO II floats to examine the spatial and diurnal variability of the ocean mixed layer (Scripps).

The PISTON field campaign was guided by a suite of numerical model simulations. Highlights of the field campaign will be presented.