The Impact Of Abnormal East Asian Winter Monsoon In China Sea Sea-air Flux And In East Asian Summer Monsoon

In this pater, using the Reynolds&Smith reconstructed monthly mean SST dataand the NCEP／NCAR monthly mean reanalysis data during the period from1948to2011,we improved the calculation of defining the East Asian winter monsoon indexand compared the similarities and differences of the results from various programs,thus based on such similarities and differences we analyze the impact of abnormalEast Asian winter monsoon in China Sea sea-air flux and the relationship betweenabnormal East Asian winter monsoon and the post-East Asian summer monsoon. Thestuy shows that:(1)There are significant differences in East Asian winter monsoon indexcalculated between using the seasonal time scale and using monthly time scales.When using the separated winter months to calculate the East Asian winter monsoonintensity index we found that nearly half of the intensity index are opposite betweenearly and late winter; If calculated in accordance with the winter average state, a lot ofspecial circumstances will be masked out; Separate month calculation makes thesituation of the winter monsoon more clearly.(2)On area, the whole area was divided into northern and southern region by20°N to calculate the index of the East Asian winter monsoon. This method ofcalculation in the spatially separated eliminated the overwritten of the true wind insome years because of the overall region calculation.,thus made the strong wintermonsoon year more representative. For instance, some years the winter monsoon inthe north of20°N were unusually strong, but within10°20°N the winter monsoonwere not so strong, such years were singled out when separated the area incalculation,further,we relatively compared situations of strong winter monsoon on thesea-air flux and summer monsoon, and got better results.(3)It can be seen from the proceeds of the winter monsoon index that there areobvious inter-annual variations and interdecadal variations. There is a boundary year,the year1987, before this year the East Asian winter monsoon was stronger, andChina’s average winter temperature was relatively lower. From1987to the winter of2010, the East Asian winter monsoon was in the weakness of the state, which couldbe used as an example of global warming. On the point of average winter state, fromthe founding to the winter of2010, the year1998had the weakest winter monsoon, orsay, the warmest winter. February2008, the winter monsoon was the strongest sincethe1990s, and this winter southern China suffered a rare snowstorm.(4)The strong East Asian winter monsoon and weak winter monsoon synthesis at500hPa,850hPa,1000hPa circulation anomaly field, latent heat flux, sensible heatflux, net heat flux and sea surface temperature distribution are of the opposite. Air-sea flux and the strength of the wind region has a good correspondence.(5)East Asian winter monsoon significantly affect China’s coastal air-sea fluxwithin the month. East Asian winter monsoon intensity index and the sea surfacetemperature have a good positive correlation over the same period, as well as the eightmonths delayed sea surface temperature. Among them, the correlation coefficient withone-month lagged sea surface temperature is0.87, indicating that the sea surfacetemperature anomaly caused by the abnormal East Asian winter monsoon could bedelayed for a month.(6)When the winter monsoon in the middle and lower reaches of Yangtze Riveris on the strong (weak)side, the summer monsoon in the range of（113°123°E，25°30°N）is on the weak (strong)side.(7)There are inter-annual variations for the outbreak of SCS summer monsoon.When the East Asian winter monsoon is abnormally strong within (110°130°E,20°30°N), while not strong in the range of (110°130°E,10°20°N), it isconductive to the early outbreak of the SCS summer monsoon; When East Asianwinter monsoon remains strong within (110°130°E,10°20°N), there are nocertain rules whether the SCS summer monsoon breaks out early or late. There areinter-annual variation and interdecadal changes on intensity of East Asian summermonsoon. In exceptionally strong(weak) East Asian winter monsoon year, the latterEast Asian summer monsoon intensity is often obviously weaker(stronger) thannormal; But these are conditions before the21st century, after2000, there is atendency of breaking out earlier for the South China Sea summer monsoon and theEast Asian summer monsoon intensity is generally weak.