Seasonal Highlights

1. Climate in China

During the winter (Dec. 2010-Feb. 2011), seasonal mean surface air temperature of China was 0.3℃ below normal (-4.3℃), being the coldest winter since 1987. Temperatures were observed near or below normal in most of China, except Qinghai, central-western Southwest China, parts of Central China, parts of western North China, northern Heilongjiang, and parts of western Xinjiang, where temperatures were more than 0.5℃ above normal, with 1-2℃ above normal in parts of above regions. Temperatures were 1-2℃ below normal in central-northern Xinjiang, western and eastern Inner Mongolia, western Northeast China, and southwestern South China, with over 2℃ below normal in parts of northern North Xinjiang and parts of western Northeast China.

For the season, averaged precipitation over China was near normal, while precipitation distribution was extremely uneven. Precipitations were observed 30%-100% more than normal in most of Inner Mongolia, most of Northeast China, northern and western Xinjiang, locations of western Qinghai, southwestern Tibet, locations of eastern Sichuan, and central-southern Yunnan, with over 100% more than normal in locations. Meanwhile, precipitations were observed 30-80% less than normal in western Liaoning, locations of western Inner Mongolia, central-southern Xinjiang, central-eastern Tibet, central Sichuan, Jiang-Huai areas, Jiang-Han areas, and southern South China, with over 80% less than normal in central-southern Xinjiang and central Tibet.

2. World Climate

During the boreal winter(Dec. 2010-.Feb. 2011), seasonal mean surface air temperatures were observed more than 0.5℃ below normal in most of Europe, central-western Russia, northern Central Asia, most of East Asia, Afghanistan, most of Pakistan, most of Australia, central and northwestern North America, with values over 4℃ below normal in northern Europe and central-southern Russia. Meanwhile, temperatures were observed significantly higher than normal in eastern North America, most of the Far East of Russia, most of West Asia, the Qinghai-Tibet Plateau, the western Indo-China Peninsula, most of North Africa, locations of northern and central-eastern South America, with at least 4℃ above normal in parts of above regions.

For the winter, precipitations were observed 30%-100% more than normal in parts of the East Europe Plain, northern coast and parts of the Far East of Russia, northern East Asia, southeastern India, the western Indo-China Peninsula, southeastern West Africa, most of Australia, parts of central and northern North America, northern and central-eastern South America, with over 200% above normal in parts of above regions. Meanwhile, precipitations were observed 30-80% less than normal in northern Europe, central Russia, most of Central Asia, most of West Asia, the Qinghai-Tibet Plateau, most of West Africa, southern North America, and locations of northwestern South America, with precipitations over 80% less than normal in parts of above regions.

3. General Circulation Features

Northern Hemisphere: During the boreal winter(Dec. 2010-.Feb. 2011), in the field of 500hPa geopotential height anomaly, positive anomalies above 4 dam covered regions from northeastern North America to northwestern Russia through the Arctic Ocean, and northern North Pacific, with central values above 16 dam over northern North Pacific. Negative anomalies of -4~-8 dam covered regions from eastern United States to the northern North Atlantic Ocean, and the middle latitudes of the Northwest Pacific.

Southern Hemisphere: During the boreal winter, in the field of 500hPa geopotential height anomaly, positive anomalies above 4 dam covered the South Indian Ocean and the South Atlantic Ocean between 40^oS-60^oS, and the middle latitudes of the South Pacific, with central values above 8 dam over the South Indian Ocean and the South Atlantic Ocean. Meanwhile, negative anomalies below -4 dam covered the southeastern South Pacific in the high latitudes.