| Since a long period of time, studies on precipitation forecasts are limited in using traditional linear statistical methods, and especially when analyzing the regional characters of precipitation, the ocular estimate and Empirical Orthogonal Function (EOF) decomposition methods etc. are generally used.. However, precipitation series is a typical nonlinear or chaotic observations, the typical statistical analysis means is not able to fully mine the dynamical signal of the time series. In the light of the recent research achievements of nonlinear science and in the context of the daily precipitation data from 1951 to 2000 at 740 stations compiled by the National Climate center, the dynamic space of precipitation at each station is first reconstructed using the time-lag method, and the regional climatic characters of summer precipitation in the monsoon area of China are then analyzed using dynamical correlation factor exponent Q, yielding the five dynamic climate characteristic regions whose property differs from the traditional "precipitation pattern", i.e. 1) Jianghuai pattern covering 65 stations; 2) South China pattern covering 49 stations; 3) North China pattern covering 59 stations; 4) Northeast China pattern covering 27 stations; and 5) Tibetan plateau pattern covering 53 stations. The statistical data show that weather (precipitation) in the five dynamic climate characteristic regions simultaneously becomes dry, wet and normal, that is to say, each region possesses a common spatial-temporal characteristic structure. Further analysis of physical mechanisms suggests that the Jianghuai pattern and South China pattern are close related with ENSO, which may results from the effect of the India-East Asia (IEA) teleconnection pattern; among the other three patterns North and Northeast China patterns are positively related with the ridge line position of subtropical high, but the ENSO shows no obvious influence on the three patterns, which may be associated with that the regions are mainly out of the weak impact area of ENSO; furthermore the influence of the ridge line of subtropical high on precipitation in North China is most remarkable. Thishas instructive significance for the development of regional climate models, and the analysis of precipitation characters and precipitation forecast. In the context of 1951~2000 June-August daily precipitation and temperature data at 740 stations compiled by China Climate Center, the dynamical mechanism of anomalous summer climate around the end of the 1970s over the east of China is emphatically discussed from the angle of nonlinear dynamics by using dynamical correlation factor exponent Q. The main conclusions are as followings: there are generally jumps of the means of precipitation and temperature in China around the end of the 1970s, however dynamical analysis results show that the dynamical structure does not change in most areas where the mean value jumps and this phenomenon is most distinctive in the Changjiang River valley; both the mean and dynamical structure of the precipitation and temperature jump in the north China region, and the dynamical analyses indicate that the persistent drought in north China the end of the 1970s may result from its dynamical jump, witch is associated with the large-scale topography of the Tibetan Plateau; dynamical jumps of precipitation and temperature over the Tibetan Plateau synchronize with those over north China or even northeast China; the analyses suggest that the teleconnection wave-trans triggered by the dynamical/thermal effects of the Plateau, disperse down-stream-wards, causing the anomaly of the regional climate system in down-stream regions, and the persistent drought may be related with this; it is found from analyzing the spatial/temporal characters of the dynamical evolution of precipitation and temperature series that the dynamical background of climate system can be reflected using different meteorological elements, but the spatial/temporal distributive r... |
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