Seasonal Highlights

1. Climate in China

During spring 2012, seasonal surface air temperature averaged over China was 10.5°C, with 0.6°C above normal (9.9℃). Temperatures were 1~2℃ above normal in northern Xinjiang, western and southern North China, central Huanghuai, eastern Jianghuai, southeastern Southwest China, with 2~4℃ above normal in locations, while temperatures were near or slightly above normal in most of the remainder of China.

For the season, the mean precipitation was 144.3mm in China, which was 5% above normal (138.1mm). Precipitations were observed 30-100% above normal in southwestern Qinghai, central Tibet, locations of western Xinjiang, central and western Inner Mongolia, southern Northeast China, parts of northern Jiangnan, with precipitations at least 100% more than normal in locations. Meanwhile, precipitations were observed 30-80% below normal in most Xinjiang, parts of western and eastern Southwest China, northern Huanghuai, with precipitations at least 80% less than normal in locations.

2. World Climate

During Spring 2012, monthly mean temperatures were 0.5-3℃ above normal in most Europe-Asia, parts of northwestern Africa, most North America, parts of mid-western South America and parts of southwestern Australia, with temperatures 3-6℃ above normal in parts of mid-northern Russia, mid-northern Kazakhstan and most mid-eastern America. Monthly mean surface air temperatures were generally observed 0.5-3℃ below normal in parts of eastern Russia, locations of southeastern West Asia, western West Africa and parts of southeastern Africa, northwestern North America, most of central and northern South America and most Australia.

For the season, precipitations were at least 30% less than normal in parts of mid-northern Europe, most of the regions from West Asia to western East Asia, mid-northern Africa, southwestern North America and mid-Alaska, parts of central and southern South America, mid-southern Australia, with no precipitation in locations. Meanwhile, precipitations were at least 30% more than normal in  eastern South Europe, most Russia, most Central Asia, northeastern South Asia, parts of mid-northern and western East Asia, most West Africa, most of northern North America, most of central and northern South America, northern Australia, with precipitations at least 200% above normal in locations.

3. General Circulation Features

Northern Hemisphere: During the boreal spring (Mar-May), the field of mean 500hPa geopotential height exhibited a four-wave pattern over mid-high latitudes. In the field of height anomaly, positive anomalies above 4 dam covered the northern North Atlantic Ocean, regions from the Sea of Okhotsk to the central-northern North Pacific, northeastern United States as well as parts of the Polar region. Negative anomalies below -4 dam covered Alaska and the oceans south to it.

Southern Hemisphere: For the season, in the field of 500hPa geopotential height anomaly, positive anomalies above 4 dam covered the regions from the Polar region to the southern South Atlantic Ocean, and the southwestern South Pacific, with central value above 8 dam over the Polar region. Negative anomalies below -4 dam covered the southeastern South Pacific around the 60oS latitudes.