Four separate (but coincident in time) field experiments to study tropical cyclones in the western North Pacific area will be carried out during August/September 1990 by the United States, the Economic and Social Commission for Asia and the Pacific/World Meteorological Organization (ESCAP/WMO) Typhoon Committee, the USSR, and by Taiwanese scientists. The objective of the U.S. experiment is to improve basic understanding of tropical cyclone motion. The focus of the ESCAP/WMO Typhoon Committee experiment is to improve operational track prediction. A multi-ship and aircraft expedition is planned by the USSR to understand the effects of the ocean inhomogeneities on tropical cyclones, and the response of the ocean to typhoon passage. Researchers in Taiwan will organize special observations of typhoons approaching Taiwan to understand the wind and precipitation distributions. The combined observations from these experiments should result in a comprehensive dataset for the study of western Pacific tropical cyclones.