The Abrupt Changes of the Summer East Asia Low In 1970s and its relationship with East Asia moonsoon

摘要

Procedures for distinguishing anthropogenic climate change from natural climate fluctuations can be divided into two parts. In the first part, an exploratory data analysis, one lifts components of slow interdecadal climate variations from the faster intradecadal climate variations. Anthropogenic climate change that evolve slowly over decades contribution to the interdecadal climate variations. Tapio Schneider and I. M. Held analyzed global temperature data in January and July from period of 1916-1998, and indicated that the surface temperature have distinctly changed over the course of the twentieth century. Both spatial and temporal feature of the dominant discriminants are consistent with expected effect of anthropogenic greenhouse gases and sulfate aerosols. The global surface temperature has distinctly increased since late 1970s, and the most prominent increase of the global temperature happened after 1970s (Tapio Schneider and I. M. Held, 2001). In 2003, Huijuan Wang pointed out that warm winter appeared more frequently and winter East Asia monsoon became weaker in the North China in recent 20 years (Huijuan Wang, 2003). Daid and Wallace analyzed the winter Arctic Oscillation index (AO) and the north hemisphere surface air temperature data (SAT), and pointed out that the SAT over the Europe-Asia continent and North-west Atlantic are a significant increase tendency after 1970s (David W.J.T and J.M.Wallace, 1998). Riyu Lu found that since the seventies of twentieth, the severity drought disaster often were appeared in middle-East China, the precipitation during July and August was decreased significantly, the northward vapor transfer over East China has a significant decrease (Riyu Lu, 2003). Martin and Arun analyzed the global surface temperature and precipitation anomalies during 1998-2002, and comparing with a 1971-2000 climatology, found that the droughts and high temperature spanning the United States, southern Europe, South-west Asia, Indian, and west Pacific oceans were unprecedented and consistent with greenhouse gas forcing (Martin H. and Arun K., 2003).