Features of the East Asian Winter Monsoon Intensity on Multiple Time Scale in Recent 40 Years and Their Relation to Climate

Utilizing the East Asian monsoon intensity indexes the features of their trend, interannual and interdecadal changes of the monsoon in January during the period of 1950~1989 and their relation to the China’s winter weather-climate are studied. It is found that the interannual and interdecadal changes of the East Asian winter monsoon were closely related to the weather in China. It was cold/dry when the winter monsoon was strong, and warm/moist weather then the monsoon was weak. However, the relationship between the monsoon and China’s climate change trend was not as good as that of the interannual and interdecadal changes. During the past 40 years, the air temperature experienced a remarkable increase, while the monsoon underwent a pronounced reduction. Since the mid-1980s, however, the winter monsoon has become rather weakened. It is also found that when the East Asian winter monsoon was strong, the atmospheric circulation showed the strong WP pattern and the EU teleconnection pattern.