Interdecadal Modulation of Summer Monsoon in Japanese Costal Waters
~The Pacific-Japan Pattern Correlates with Rice Yields and Typhoons~

A joint research team of Dr. Hisayuki Kubota, Department of Coupled Ocean-Atmosphere-Land Processes Research (DCOP) at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) with Prof. Yu Kosaka, Research Center for Advanced Science and Technology at The University of Tokyo, and Prof. Shang-Ping Xie, Scripps Institution of Oceanography at University of California defined the Pacific-Japan (PJ) pattern, a dominant pattern of interannual variability for the Western North Pacific and East Asian summer monsoons, by digging out and examining atmospheric pressure data over 117 years from 1897 to 2013.

This long-term modulation revealed that the PJ index is correlated with climate variables including air temperature precipitation, Japanese rice yield, Yangtze River flow, and the occurrence of tropical cyclones in Taiwan and Okinawa region. The relationship between PJ index and El Niño-Southern Oscillation was modulated on interdecadal timescale, which influences correlation with climate variables in interdecadal timescale. These study results will contribute to seasonal forecast in Japan and East Asia summer, especially for climate factors such as typhoons, extreme hot and cool summer, which affect significantly people’s lives and agriculture.