Open AccessSteady decline of east Asian monsoon winds, 1969–2000: Evidence from direct ground measurements of wind speed
Author(s) -
Xu Ming,
Chang ChihPei,
Fu Congbin,
Qi Ye,
Robock Alan,
Robinson David,
Zhang Huaimin
Publication year - 2006
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006jd007337
Subject(s) - monsoon , climatology , environmental science , east asia , latitude , east asian monsoon , wind speed , global warming , greenhouse gas , atmospheric sciences , global wind patterns , china , climate change , geography , oceanography , geology , meteorology , archaeology , geodesy
It is commonly believed that greenhouse‐gas‐induced global warming can weaken the east Asian winter monsoon but strengthen the summer monsoon, because of stronger warming over high‐latitude land as compared to low‐latitude oceans. In this study, we show that the surface wind speed associated with the east Asian monsoon has significantly weakened in both winter and summer in the recent three decades. From 1969 to 2000, the annual mean wind speed over China has decreased steadily by 28%, and the prevalence of windy days (daily mean wind speed > 5 m/s) has decreased by 58%. The temperature trends during this period have not been uniform. Significant winter warming in northern China may explain the decline of the winter monsoon, while the summer cooling in central south China and warming over the South China Sea and the western North Pacific Ocean may be responsible for weakening the summer monsoon. In addition, we found that the monsoon wind speed is also highly correlated with incoming solar radiation at the surface. The present results, when interpreted together with those of recent climate model simulations, suggest two mechanisms that govern the decline of the east Asian winter and summer monsoons, both of which may be related to human activity. The winter decline is associated with global‐scale warming that may be attributed to increased greenhouse gas emission, while the summer decline is associated with local cooling over south‐central China that may result from air pollution.