Northeastern Region Of Atmospheric Circulation And Climate Relationship

Under the background of global climate change, the climate change in differentregions is quite different. In order to research on the regional climate change in NortheastChina, the close relationship between atmospheric circulation types and the climate ofNortheast China is deplored in depth. Firstly, the applicability of the Lamb-Jenkinson classification scheme is verified inNortheast China. Then, it is applied to obtain circulation types from mean sea-levelpressure on a daily basis in a region of 35 longitude by 25 latitude in which NortheastChina is included from 1951 to 2004. Daily mean sea-level pressure data is used to derivesix circulation indices and to provide a circulation catalogue with 27 circulation types.Eight major types (N, NW, NE, A, C, S, SW and W) which occur most frequentlyare analyzed deeply to reveal their characteristics on various time scales, the days ofmaintenance and the features of changing into other circulation types. Furthermore,relationships between circulation types and precipitation and temperature are studied andnine representative stations with a long record of meteorological data are investigateddeeply. Stepwise linear multiple regression is used to reconstruct temperature andprecipitation series in nine representative stations respectively.The results show that Lamb-Jenkinson classification scheme can be applied easilyand the atmospheric circulation types obtained match well with the real world. Forexample, dominant types in winter are N,NW,NE and A types, which favor a negativetemperature anomaly and correspond to less rainfall. However, C and S types occurfrequently in summer and often induce a positive temperature anomaly and correspond tomore rainfall. On the basis of mean precipitation and temperature from 1951 to 2004,differences of precipitation and temperature distribution between different circulationtypes are obvious and can change with seasons. Due to the close relationship between climate in Northeast China and the atmosphericcirculation types, regression equations established by using circulation indices andlarge-scale mean temperature can successfully reconstruct temperature series in ninerepresentative stations of Northeast China between 1951 and 2004, which reveal thechange of temperature in recent years. Moreover, the precipitation series constructed in thesame way in the latest 54 years are similar to those of observed in nine stations with highcorrelation coefficients, which can explain the majority of precipitation change in thesame period.Research on the relationship between atmospheric circulation types and regionalclimate in Northeast China can not only reveal the reason for climate change in NortheastChina but also can be viewed as a useful reference for climate prediction on various timescales and the test of results from climate models.