Summer climate prediction of China in 2017 Sun Jilin College of Oceanic and Atmospheric Science Key Laboratory of Physical Oceanography.MOE.China Ocean University of China 2017-4-25,Beijing

Methods Most reasoning by mechanism of ocean-atmosphere interaction，atmospheric dynamics. associated by statisitical analysis combined many features in global ocean and atmosphere, positive feed backs in tropical ocean-atmosphere system, especially considering possibale variation of cold air in Southern Hemisphere, making decisions at last

positive heat content anomaly still at eastern equatorial Indian Ocean

atmospheric responsibale to forced steady heating Niño 4 0.0ºC The anomalous circulation will be favorabale for landing of typhoon

comparison among years of 1984, 1999,and 2017 in winter

comparisons among 1984, 1999 and 2017 in winter

comparisons among 1984, 1999 and 2017 in winter: no cold air in arctic than that in 1999

Prediction for anomalous atmospheric circulation Subtropical High：during late summer and early autumn, it will located little northward than normal，favors more rain in the vicinity of Huaihe River to Yellow River. At the southside of Yangtze River, there will be staged high air temperature with less rainfall during the early autumn。 At high latitudes：anomalous northwesterly passed Baikal lake will make less rain in north China.

climate prediction The main rain belt in summer 2017 is at the north of Yangtze River to Yellow River centred at Huaihe River. Rainfall affected by typhoons will be more in south part of China. Summer monsoon over the South China Sea will be little earlier than normal（in the middle of May)，less rainfall will be for north China. Typhoon prediction：landing: （8~9个）,little more than normal, typhoon with super strength（2~3个）.

disaste weathers typhoon with super strength（2~3) affecting China, little more than normal：areas: Taiwan、Guangdong、Zhejiang、Fujian、jiangxi heavy rains：at late spring and early summer：Zhujiang River、south of Yangtze River; at summer:：Huaihe River and south of Yellow River(more)，north of China（less），northeast of China（normal） flooding：Huaihe、Zhujiang、Yangtze River Drought：North of China，during middle summer to early autumn: south of Yangtze River

reasons in prediction 1、estemated by physical mechanism, there is little possibility of El Nino event in 2017,warm water will still at its normal position; 2、cold air at southwestern direction of Australia will enhance the cross-equator stream to north hemisphere to strengthen the ITCZ. The strengthening of ITCZ will generate more typhoon and push subtropical high northward.

reasons in prediction 3. the positive ssta in Sea of Barron and negative ssta in sea of Okhotsk will force anomalous northwesterly over Baikal areas which will not favor the rainfall in the northern part of China.

predicted percentage of rainfall anomaly

predicted summer air temperature anomaly

Thanks a lot

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