Seasonal Highlights

1. Climate in China

During autumn of 2011, the whole country seasonal mean surface air temperature was 10.3^oC with 1.1 ℃ above normal (9.2℃) being the 4th highest since 1951. Temperatures were 1~2℃ above normal in most Xinjiang, most Gansu, most Qinghai, northern Xizang, most Guizhou, parts of mid-northern and southern Sichuan, mid-western and eastern Inner Mongolia, most Heilongjiang, western Jilin, northern Shanxi, central Hunan, most Jiangxi, southern Anhui, southern Jiangsu, most Zhejiang, mid-western Fujian, eastern Guangxi, etc., with 2～4℃ above normal in locations of Xinjiang, Qinghai and Xizang.

   For the season, the average precipitation over China was 131.9 mm, with 9.6% more than normal (120.3mm). Precipitations were observed at least 30% more than normal in parts of northern and western Xinjiang, southern Qinghai, eastern Gansu, Ningxia, Shaanxi, central Inner Mongolia, Shanxi, mid-southern Hebei, Tianjing, Shandong, mid-northern Henan, northern Hubei, eastern Sichuan，western Guangxi, northern Guangdong, southern Hunan, southern Jiangxi, southern Fujian and parts of central Xizang, with 100% more than normal in locations of western Xinjiang and southeastern Gansu, southern Ningxia, most Shaanxi, southern Shanxi, southern Hebei, central Shandong and northern Henan. Meanwhile, precipitations were 30% ~ 80% less than normal in southern Xinjiang, western Gansu, northern Qinghai, western and eastern Inner Mongolia, southern Heilongjiang, central Jilin, western Liaoning, southern Jiangsu, southern Anhui, southern Hubei, northeastern Hunan, northern Jiangxi, part of northern Zhejiang, southern Sichuan, northern Yunnan and western and southeast Xizang, etc.

For the season, daily temperature drop extremes, consecutive temperature drop extremes, daily rainfall amounts extremes, three-day rainfall amounts extremes, consecutive rainfall amounts extremes, and consecutive rainy days extremes were observed in China.

Daily temperature drop extremes occurred in 58 stations of thirteen provinces in most Northeast China, eastern Inner Mongolia, eastern North China and eastern Southwest China. The widespread daily temperature drops reached up to 10-16℃, with Hailar (15.3℃) and Zhongxian (13.4℃) breaking record. Consecutive temperature drop extremes were observed in 12 stations of Inner Mongolia, Shandong, Xizang, Guizhou and other provinces, with consecutive temperature drops up to 15-25℃, and Chenbaerhu (25.4℃) and Manchuria (23.9℃) breaking record.

For the season, daily rainfall amounts extremes occurred in 30 stations of Shaanxi, Sichuan, Guangxi, Hainan, Fujian, Zhejiang and other provinces, with Binyang (347 mm), Shanglin (271.2 mm), Yongning (267.9 mm), Haikou (334 mm), Putian (313.8 mm), Tiantai (182.5 mm), Longling (167.7 mm) and Bole (48.6 mm) breaking record. Meanwhile, three-day rainfall amounts extremes occurred in 35 stations of mid-western Shaanxi, southern Shanxi, northwestern Henan, eastern Sichuan, southern Guangxi, and northern Hainan, with Binyang (396.9 mm), Yongning (360.3 mm), Shanglin (322.6 mm), Wuming (270.9 mm), Zhouzhi (159.7 mm), and Meixian (141.8 mm) breaking record. Additionally, consecutive rainfall amounts extremes were observed in 51 stations, distributed in Shaanxi, Henan, Shandong, Guangxi, Hainan and Sichuan, with Danzhou (870.2 mm), Haikou (828.3 mm), Baisha (750.5 mm), Wuzhishan (615.6 mm), Ziyang (496 mm), Yongning (584.5 mm), Binyang (508.9 mm), Wuming (476.7 mm), Longan (413.2 mm), and Fusui (374.9 mm) breaking record. Consecutive rainy days extremes occurred in 83 stations, which were located in most Henan, mid-western Shandong, Hainan, and parts of Sichuan, with Lushan (25 days), Mingshan (22 days), Suiyang (22 days), Danjiangkou (17 days), Chengkou (17 days), Ziyang (17 days), Shangcai (16 days), Jiaxian (15 days), Jiyuan (11 days), Mengjin (10 days), Pingyin (9 days), Liangshan (9 days) breaking record.

2. World Climate

During autumn 2011, seasonal mean air temperatures were 0.5-2℃ below normal in most West Asia, eastern Central Asia, Mongolia, northwestern Australia, southwestern Africa, parts of northwestern North America, northwestern and eastern South America, with temperatures were at least 2℃ below normal in locations. Temperatures were near or above normal in the rest of the world, with 0.5-3℃ above normal in most areas, and over 3℃ higher than normal in northern Europe, parts of northern Russia, southeastern West Asia, and parts of eastern North America.

For the season, precipitations were 30-50% above normal in the Russian Far East and parts of western Russia, most West Asia, most Central Asia, mid-eastern China, eastern part of the Indo-China Peninsula, parts of West Africa, most Australia, southeastern and southwestern North America, northern and eastern South America, with precipitations at least 100% above normal in locations. Meanwhile, precipitations were 30-50% below normal in most Europe, southern Russia, Mongolia, Northwest, Northeast and Southwest China, eastern Central Asia, central India, southern and parts of northern Africa, central and northwestern North America, central and southern South America, with no precipitations in locations.

3. General Circulation Features

Northern Hemisphere: During the autumn of 2011, the field of mean 500hPa geopotential height exhibited a 4-wave pattern over the mid-high latitudes. In the field of height anomaly, positive anomalies above 4 dam were located in most Europe, central North Pacific and locations of northern North America, respectively, with central values above 8 dam over locations of western Europe. Meanwhile, negative anomalies below -4 dam covered Central Asia, the Russia Far East, northern North Pacific and northern Atlantic Ocean, with central values below -8 dam over northern North Pacific and locations of northern Atlantic Ocean.

Southern Hemisphere:  For the month, the field of mean 500hPa geopotential height mainly exhibited zonal circulation with negative anomalies belt around the middle latitude，with the central values below -4 dam over the southeastern South Indian Ocean. Meanwhile, positive anomalies above 4 dam covered the polar areas and western Atlantic Ocean, with central values above 8 dam over the polar areas.