Seasonal Highlights

1. Climate in China

During summer of 2013, the average precipitation over China was 339.9 mm, with 4.5% more than normal. The distribution of precipitation anomalies percentage showed positive anomalies in the northern part and negative anomalies in southern part. Precipitations were observed at least 30%-100% more than average in northern and southeastern Northeast, northeastern Inner Mongolia, western North China, most Northwest China and western Xizang, with 100% more than normal in parts of the above regions. Meanwhile, precipitations were 30% ~ 50% less than normal in western Huang-Huai, eastern Jianghuai, western Jiangnan, Guizhou, mid-northern Qinghai and northeastern Xinjiang, with 50-80% less than normal in locations. Seasonal precipitations were the 1^st highest in Heilongjiang, the 2^nd highest in Gansu and the 2^nd lowest in Guizhou since 1951.

For the season, the whole country seasonal mean surface air temperature was 21.7°C with 0.7°C above normal being the 1^st highest since 1961 same as 2006 and 2010. Temperatures were 1~2℃ above normal in most regions from southern North China to northern Jiangnan, most Guizhou, Chongqing, Sichuan, northern Xizang, Qinghai, and southern Shaanxi, with over 2℃ above normal in parts of above regions. Temperatures were 0.5~2℃ below normal in northern Xinjiang, northeastern Inner Mongolia and Hainan. Seasonal mean surface air temperatures were the highest since 1961 in Qinghai, Henan, Jiangsu, Shanghai, Zhejiang, Jiangxi, Hubei, Hunan and Guizhou, and the 2^nd highest in Anhui, Shaanxi, Sichuan, Chongqing and Yunnan.

2. Climate in the World

During summer 2013, monthly mean temperatures were 1-2℃ above normal in  northwestern Eurasia, mid-eastern East Asia, most Australia and mid-western North America, with temperatures at least 2℃ above normal in locations of northeastern of Europe, northwestern Russia and northwestern Canada. Meanwhile, temperatures were 1-2℃ below normal in most Central Asia, parts of northern and southwestern Africa, locations of northeastern North America,  mid-western South America, with temperatures at least 2℃ below normal in locations of central South America.

For the summer, precipitations were at least 50% above normal in southeastern Europe, Central Asia, northern East Asia, northeastern Russia, mid-northern South Asia, southern West Africa, mid-western Australia, eastern North America, mid-northern South America, with precipitations at least 200% above normal in locations. Meanwhile, precipitations were 50%-80% below normal in mid-northern Russia, West Asia, northern and central Africa, northeastern Australia, locations of northwestern North America, parts of southern South America, with no precipitation in locations of above regions.

3. General Circulation Features

Northern Hemisphere: During summer 2013, a four-wave pattern was observed in mid-high latitudes of the field of mean 500 hPa geopotential height. In the field of height anomaly, negative anomalies below - 40 gpm covered parts of the Arctic Region near Greenland. Heights were found near normal in the rest areas.

Southern Hemisphere:  In the field of seasonal mean 500 hPa geopotential height anomaly, positive anomalies above 40 gpm covered most of the Antarctic and parts of the southeastern South Pacific with central values above 80 gpm. Meanwhile, negative anomalies below -40 gpm covered the southeastern South Pacific south to the end of South America, with central values below - 80 gpm.