Seasonal Highlights

1. Climate in China

During winter of 2012/2013, the seasonal surface air temperature averaged over China was -3.7°C, with 0.3°C below normal (-3.4℃). For the season, the temperature had two-stage variations, with the temperature warmer in the pre-winter and colder in the late winter. Temperatures were below normal in most of Northeast China, eastern Inner Mongolia, most of North China, most of Central China, northern and middle Xinjiang and parts of western Tibet, with 2~4℃below normal in most of Northeast China, eastern Inner Mongolia, northeastern North China, northern Xinjiang and locations of western Tibet and with 4℃ below normal in locations, while temperatures were near or slightly above normal in most of the remainder of China, with 1-2℃ above normal in most of Yunnan and southern Qinghai.

For the season, the mean precipitation was 36.5mm in China, which was 10.3% below normal (40.7mm). The precipitation were unevenly distributed, with less precipitation in Southwest China and more in Northeast China. Precipitations were observed 50-200% above normal in most of Northeast China, eastern Inner Mongolia, eastern and southern North China, most of East China, middle West China and western Tibet, with precipitation at least 200% above normal in locations. Meanwhile, precipitations were observed 50-80% below normal in most of Southwest China, eastern South China, western Central China, middle Inner Mongolia and southwestern Xinjiang, with precipitations at least 80% less than normal in Yunnan and western Sichuan.

2. World Climate

In winter of 2012/2013, temperature in most places of the world was colder than normal. Temperatures were 1-4℃ below normal in most Asia, northwestern Africa, central-northern and southwestern North America, northern South America, with temperatures more than 4℃ below normal in northern East Asian and parts of southern Russia. Meanwhile, temperatures were 1-2℃ above normal in southeastern Europe, most West Asia, northwestern Southeast Asia, western Australia, eastern North America and northwestern Canada, with temperatures at least 2℃ above normal in northwestern Canada and parts of southeastern America.

For the winter, precipitations were observed 50-100% more than normal in southern Europe, most West Asia, Central Asia, central South Asia, most Northeast China, central-northern and northwestern North America, northern and southeastern South America, with precipitations at least 200% above normal in parts of above regions. Meanwhile, precipitations were at least 50% less than normal in central-northern Russia, most Southwest China, central-eastern Australia, northern Africa, northeastern Canada and parts of western South America, with no precipitations in parts of above regions.  

3. General Circulation Features

Northern Hemisphere: During the boreal winter(Dec. 2012-.Feb. 2013), in the field of 500hPa geopotential height anomaly, positive anomalies above 4 dam covered regions from the northeastern North America to the northeastern Europe and the eastern North Pacific, with central values above 12 dam over part of northern North Atlantic Ocean and eastern North Pacific. Meanwhile, negative anomalies below -4 dam covered part of western North Atlantic Ocean, the western Europe and the Baikal of eastern Russia, with central values below -8 dam over part of western Europe.

Southern Hemisphere: During the boreal winter, in the field of 500hPa geopotential height anomaly, it exhibited a significant annular mode, negative anomalies covered most areas between 40°S and 60°S, with negative anomalies below -4 dam covering the Weddell Sea. Positive anomalies above 4 dam dominated the Southeast Pacific Basin, with parts over 8 dam.