Seasonal Highlights

1. Climate in China

During the autumn (Sep-Oct-Nov) of 2013, the seasonal mean surface air temperature over China was 10.5℃, which was 0.6℃ above normal (9.9℃). Temperatures were mostly near or above normal in most China except parts of western China which has temperature anomalies of about 0.5℃ below normal. Temperatures were 1-2℃ above normal in northern Xinjiang, western and northeastern Inner Mongolia, central-northern Northeast China, regions from southeastern Southwest China to parts of northwestern Huanghuai, and western Tibet, with over 2℃ above normal in locations of the above regions.

For the season, the average precipitation over China was 122.4 mm, with 2.2% slightly more than normal (119.8 mm). Precipitations were 30%-50% more than normal in most Northeast China, parts of eastern Inner Mongolia, parts of western and northeastern Northwest China, central and eastern Tibet, parts of northwestern Southwest China, and regions from western Jiangnan to western South China. Meanwhile, precipitations were near or less than normal in the rest of China, with 30% - 80% less than normal in most central-western Northwest China, western and parts of central Inner Mongolia, and regions from southeastern Northwest China to most Huanghuai, and with no precipitation in parts of the above regions during the season.

In Autumn, extremes of Daily Precipitation (DP), Consecutive Precipitation (CP) and Daily Temperature Drop (DTD) were observed in China. DP extremes occurred in 71 stations, which were located in Jiangsu, Hubei, Hunan, Zhejiang, Shanghai, Fujian and Guangxi et al., with new records in 19 stations such as Rui’an (386.6 mm), Shangyu (373.0 mm), Yuyao (344.7 mm) of Zhejiang, Songjiang (239.8 mm) of Shanghai and Fusui (197.6 mm) of Guangxi. CP extremes occurred in 33 stations, which were located in Inner Mongolia, Shaanxi, Jiangsu, Zhejiang, Shanghai and Chongqing et al., with new records in Haining (467.1 mm), Cixi (380.2 mm) and Shangyu (452.0 mm) of Zhejiang, and Qidong (300.1 mm) of Shanghai. At the same time, DTD extremes occurred in 52 stations, which were located in Heilongjiang, Jilin, Liaoning, Inner Mongolia, Beijing, Tianjin, Henan, Qinghai and Jiangsu et al., with new records in Fuxin (17.1℃) and Yixian (14.7ºC) of Liaoning, Nong’an (16.4℃) of Jilin, Miyun (14.0℃) of Beijing, Baodi (12.7℃) of Tianjin and Xiuwu (11.2ºC) of Henan.

2. Climate in the World

During Autumn 2013, mean temperatures were 0.5-2℃ above normal in most Eurasia and Australia, mid-western Africa, northwestern and mid-eastern North America, location of northwestern South America, with temperatures 2-4℃ above normal in most southern Russia and northeastern Central Siberia Plateau, location of mid-eastern Australia and part of northwestern North America. Mean temperatures were generally observed 0.5-2℃ below normal in the Far East of Russia, location of  central West Asia, parts of mid-northern and southwestern Africa, parts of central and southern North America, most northern South America, with temperature more than 2-4℃ below normal in location of mid-western North America.

For the season, precipitations were 30% to 200% more than normal in eastern Europe, most Siberia, northern East Asia, the western coast of the Indo-China Peninsula, northeastern South Asia, most West Asia, parts of northwestern, mid-northern and central Africa, southern North America and eastern Alaska, eastern South America and mid-northern Australia, with precipitation over 200% above normal in central West Asia and location of mid-northern Africa. Meanwhile, precipitations were 30% to 80% less than normal in western Central Asia, northern South Asia, mid-western East Asia, most Australia, western North Africa, northern Central Africa and central South Africa, parts of eastern and northwestern North America, and western South America, with precipitation over 80% less than normal in parts of above regions.

3. General Circulation Features

Northern Hemisphere: During the autumn of 2013, in the field of 500hPa height anomaly, the positive anomalies above 4 dam were located in the northern North Pacific Ocean and locations of the northeastern North Atlantic Ocean. Meanwhile, slightly negative anomalies covered most of the polar region.

Southern Hemisphere: For the season, in the field of mean 500hPa height anomaly, the negative anomalies above 4 dam covered most of the Antarctic Continent and parts of the southern South Pacific Ocean, with the central values above 12 dam over locations of the Antarctic Continent. Meanwhile, the negative anomalies below -4 dam covered the southwestern South India Ocean.