季气候概况

Climate in China

During the summer, mean surface air temperatures were observed above normal in most of China, except the regions between Huanghe River and Huaihe River and western regions between Huanghe River and Yangtse River. Mean surface air temperatures were observed 1℃ above normal in northern North China, most Northeast, most Inner Mongolia, eastern Jiangnan, parts of South China, southeastern Xinjiang, western Tibet and northern Gansu, with more than 2℃ above normal in eastern Xinjiang and eastern Inner Mongolia.

In the season, precipitations were observed 30-50% below normal in northern Northeast, northern North China, eastern Inner Mongolia, parts of eastern Jiangnan, the regions from western Xinjiang to western Tibet and northwestern Qinghai. Meanwhile, precipitations were observed 30-50% above normal in northern and central and southern Xinjiang, central Tibet, most of the regions between the middle and lower reaches of the Yangtse River and the Huanghe River.

Climate in the world

During the season, mean surface air temperatures were observed 1-2℃ above normal in most Europe, most Asia, northern and parts of southern Africa, central and western North America, northeastern South America and southwestern Australia, with more than 2℃ above normal in eastern Europe, northeastern Asia , western America and parts of northeastern South America. Meanwhile, mean surface air temperatures were observed more than 1℃ below normal in parts of southern North America, southern South America, parts of northwestern South Asia and northern Australia.

In the season, precipitations were observed 30-50% above normal in western and northeastern Europe, central and parts of western Asia, central and western Siberia, southern South Asia, southern North America, northern South America, western and parts of southern Africa and eastern Australia. Meanwhile, precipitations were observed 30-80% below normal in southeastern Europe, eastern West Asia, northern South Asia, parts of the Northeast Asia, western America, most of central and northern South America and central and western Australia, with no precipitation in locations of above areas.

General Circulation Features

Northern Hemisphere: During summer 2007, the mean 500hPa geopotential height field exhibited a 5-wave pattern at the mid-high latitudes. In the 500hPa height anomaly field, positive anomalies above 4 dam covered the Bering Sea, regions from the polar region to Greenland, southeastern Europe and parts of areas south to the Baikal Lake, with center value more than 12 dam above normal over the polar region.

Southern Hemisphere: In the season, meridional circulation prevailed at most of the mid-high latitudes. In the 500hPa height anomaly field, negative anomalies more than -4 dam below normal covered the southern South Indian Ocean, the southwestern South Atlantic Ocean and the southwestern South Pacific Ocean, with center value more than -8 dam below normal over southern South Indian Ocean. Meanwhile, positive anomalies more than 4 dam above normal covered the Antarctica and seas nearby, regions from the southeastern South Pacific Ocean to parts of regions in the central South Pacific Ocean, with center value more than 12 dam over the Antarctica.