| Using CMA-STI tropical cyclones' best path datasets of China Typhoon Network, the interannual and monthly variations and regional distribution of the tropical cyclones turning eastward are analyzed for the period from 1949 to 2008.The causes of eastward-turning from 2000 to 2008 are diagnosed in terms of the situation of the atmospheric circulation,the subtropical high area index,the 500hPa u wind field ,the 500hPa variable high field ,the 200hPa divergence field ,the south drop of subtropical high,the effect of double vortexes,and the moving speed of the tropical cyclones,based on the 1°×1°NCEP/NCAR reanalysis grid data. The main conclusions are as follows:1) The eastward-turning tropical cyclones China from 1949 to 2008 experience higher-lower-higher stages,and it is in high stage now; this kind of tropical cyclones mainly occur from June to September,with the largest number in September; the tropical cyclones that turn eastward offshore mainly happen in the South China Sea,and secondly in the East China Sea;the tropical cyclones that turn eastward in land mainly happen in the coastal,especially in Fujian and Zhejiang provinces,and the tropical cyclones of turning eastward in inland provinces mainly happen in Anhui province.2) Turning eastward of the tropical cyclones of from 2000 to 2008 is mainly related to the large scale circulation situation field of the east asia range,and strong and weak of the subtropical high,the change of the environment wind field, the effect between double vortexes,and the moving speed of the tropical cyclones,in addition. 3)Some main factors are screened out by analyzing turning eastward of the tropical cyclones;the configuration models of the tropical cyclones turning eastward are studied,and eight configuration models of the tropical cyclones turning eastward are setted up.
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