Comparison Of Reanalysis Data And Observation About Summer Maximum Temperature On Different Time Scales In The Eastern Part Of China

In this paper, using ground observation data set (OT) provided by China meteorological administration meteorological science data sharing network and JRA-55, ERA-Interim, NCEP/NCAR and NCEP/DOE four reanalysis data concentration of daily maximum temperature data.Using linear analysis, variance analysis, methods of EOF analysis, filter and harmonic, to study the distribution and variation characteristicsof high temperature,high temperature threshold and high temperature days 1979-2013 summer with different time scales in eastern China.Analyzing the ability of reanalysis data to reappear the observation datain the high temperature events and attempting to evaluating the applicability of reanalysis data of seasonal oscillation scale. Main conclusions are as follows:(1)From years on average,the highest temperature reduced gradually from south to north.The highest average temperature of south China, east China, central China region in summer isabove 30℃; Among them, the ERA-Interim reproduction ability is the best, and the distribution pattern of the highest temperature is similar to observation data, Followed by JRA-55. Nearly 35 years, in the eastern region, the highest temperature in summer presents the overall growth trend, the trend of the middle and lower reaches of the Yangtze river and eastern Inner Mongolia region growth is obvious. The ability of the reanalysis data to reproduce the characteristics of observation data from high to low is JRA-55, NCEP/DOE, ERA-Interim, NCEP/NCAR.(2)Maximum temperature in summer which removing the linear,mainly shows the north to the Yangtze River and the south to the the Yangtze River of reverse phase change.The spatial distribution characteristics of ERA-Interim are similar to the observed data, and the second is NCEP/DOE.The amplitude of wave is strong during 1990s to twenty-first Century. Mainly shows the inter-annual features, ERA-Interim is the closest to the observation data, and JRA-55, NCEP/NCAR and NCEP/DOE is relatively similar to the observation data after the 21st century.(3)The average threshold of highest temperature in summer shows the East and central area of Southern China is large, and the threshold decreases from south to north.Combined with range, location and strength of the large value area, the ability of JRA-55 is best, and then followed by NCEP/DOE, ERA-Interim and NCEP/NCAR.For the spatial similarity of the high temperature threshold, the reanalysis data are similar to the observed data.The relevant distribution from high to low latitude, northeast to southwest decreased gradually.In the Northeast region,the distribution of relevantsimilarity is strong.Among them, ERA-Interim is the most close to the observed data,Followed by NCEP/DOE, JRA-55, NCEP/NCAR.(4)The EOF analysis of high temperature daysshows a consistent change in the country.Before the middle of 1990 s, the high temperaturedays in north China are more than the south.There is an obvious 2-3 years cycle in the 1990s to the early 21st century. In the space field, the ERA-Interim is the closest to the observation data,followed by JRA-55.In the time field,JRA-55 reanalysis data is the closest observation data.(5) In the summer of 2013, the middle and lower reaches of the Yangtze river region is of high temperature.The range of high temperature is large, center is located in south anhui, jiangxi and zhejiang.The regional distribution of JRA-55、 ERA-Interim is close to the observation data,followed by NCEP/DOE. The overall trend of seasonal oscillation curve of reanalysis data and the observation data is the basic consistent, slightly difference in intensity, we know JRA-55 is the closest to observation data, followed by NCEP/DOE, ERA-Interim and NCEP/NCAR respectively.The main period of summer daily temperature is 20 to 60 days. The variance contribution of highest temperature summer day in ISO time scales is larger in eastern yunnan-guizhou region and northeast China, gansu and shaanxi area. JRA-55 and ERA-Interim reanalysis data are close to observation data, followed by NCEP/DOE、NCEP/NCAR.