Study On The Non-Linear Dynamic Mechanism Of Precipitation And Its Relationship With Various Indexes Of Silk Road Pattern During The Rainy Season In East Asia

China is located in the East Asian monsoon region,and the interannual variability of precipitation is relatively large,which is prone to extreme weather and climate events such as drought and floods.Therefore,it is of great practical significance to tap the inherent nonlinear dynamic mechanism of precipitation and study the external factors affecting its occurrence.In this paper,based on the data of daily precipitation stations in China from April to September 1960-2017,the percentile threshold method is used to determine the precipitation events of different intensities,and the interval between adjacent precipitation events of the same intensity is defined as the "silent time".Describe the length of time that the same threshold precipitation event occurred again.Calculate the "average silence time"to characterize the cluster characteristics of precipitation events of different intensities,that is,the smaller the average silence time(larger)in a certain period of time,the shorter the duration(longer)of the same type of precipitation event occurs again,and its mass The stronger the degree(weak).Analyze the spatial distribution and temporal evolution characteristics of the average silent time of different intensity precipitation events in eastern China,and explore its nonlinear dynamic characteristics;second,for the summer "Silk Road Pattern"(SRP)under different definitions Correlation index.Analyze the influence of each Silk Road remote correlation index on the characteristics of the Silk Road remote correlation,and study its impact on summer precipitation in East Asia and the potential connection with sea temperature.The main conclusions are as follows:(1)The final results show that the massive feature of general intensity precipitation event was stronger in the middle regions of the Yangtze River than in other areas while the southeastern part was weaker;The massive feature of extreme precipitation events was stronger in the northern part of China but the opposite in the south from 1960 to 2017.As far as the climatic state evolution process is concerned,the massive feature of the general intensity precipitation group has a certain enhancement in the south of the Yangtze River,and the weakening trend in the southeastern part of the eastern part of China;The cluster characteristics of the extreme precipitation events are weakening in the northeastern part of China but the opposite in the south.(2)The probability distribution of the quiet time of different threshold precipitation vents and the time interval of the sand collapse in the sand model(self-organized critical classical model)are in good agreement with the power law distribution and the scale-free feature,the same feature are also found in the distribution of the quiet time of the vertical velocity and relative humidity who have a direct impact on the formation of precipitation.Finally,we find that a theoretical scale function can be used to describe the precipitation events who have a self-organized critical characteristic and the extreme precipitation events can be treated as the collapse behavior that from the quantitative change to the qualitative change of the self-organized critical systems.(3)The correlation between the 200hPa meridional wind field/potential height field,the 500hPa meridional wind field and the comprehensively defined SRP remote correlation index and the 200hPa meridional wind field shows a better SRP tele-correlation type In Eurasia.The correlation with the 500hPa geopotential height field is a weak"-+-+"tele-correlation type.This is because the upper layer of the troposphere is more suitable for linear wave propagation than the lower layer of the troposphere.Although affected by the circulation,the correlation between each index and summer precipitation in East Asia is weak,but the SRP index calculated at the 500hPa geopotential height field is more indicative of precipitation than the meridional wind field index.In summary,we can consider the occurrence of extreme precipitation events as the collapse behavior of the self-organized critical system from quantitative change to qualitative change that a new interpretation of the nonlinear dynamic mechanism of precipitation events in East Asia can be given through the perspective of time series analysis.At the same time,different calculation methods of the Silk Road index and the associated precipitation analysis will also be different.Among them,the index defined by the 500hPa geopotential height field is better.