Monthly Highlights

Climate in China

During November 2008, monthly mean surface air temperatures were warmer than normal in most areas of China, with 1~2℃ above normal in most central and western Northwest China, central-western Inner Mongolia, North China, western Huanghuai, central Jianghan and central-western Tibet. Temperatures were observed above 1℃ below normal in parts of central-eastern Tibet.

For the month, precipitations were observed 50~200% more than normal in southern Northwest China, parts of central-eastern Inner Mongolia, central Northeast China, most regions south to the Yangtze River and locations in central-eastern Tibet, with over 200% more than normal in locations. Meanwhile, precipitations were observed 30~80% less than normal in northern Northwest China, western Inner Mongolia, North China, Huanghuai, Jianghuai, Jianghan, central South China, western Hainan and central-western Southwest China, with over 80% less than normal in parts.

Climate in the World

During November 2008, temperatures were at least 1℃ above normal in most Eurasia, southern Africa and central-eastern North Africa, most North America, southern and parts of eastern South America and locations in northern Australia, with temperatures at least 4℃ above normal in central-western and northeastern Russia, southwestern West Asia, parts of central-northern North America and locations in southeastern South America. Meanwhile, temperatures were 1~4℃ below normal in locations in southwestern Europe, locations in central Russia, western North Africa，southeastern North America, western Alaska and western Australia.

For the month, precipitations were at least 50~100% more than normal in most southern Russia, most Northwest and southern China, Indo-China Peninsula, locations in southeastern Africa, central-northern North America, parts of northwestern and eastern North America, most northwestern South America and most Australia, with precipitations at least 200% more than normal in locations. Meanwhile, precipitations were observed at least 50% less than normal in locations of northeastern Russia, most Mongolia, North China and most Southwest China, most Central Asia, West Asia and South Asia, most North Africa, central-southern North America, northern Central America and parts of central-southern South America, with no precipitations in locations.

General Circulation Features

Northern Hemisphere: During November 2008, in the 500hPa geopotential height anomaly field, positive anomalies above 4 dam covered regions from southeastern Europe to northern Central Asia, northern South Asia, vicinity of Kamchatka Peninsula, regions from the northeastern Pacific Ocean to the northern North Atlantic Ocean across northwestern North America, with central values above 16 dam over the northern North Atlantic Ocean. Meanwhile, negative anomalies below -4 dam covered northwestern Europe and the Norwegian sea, regions from southwestern Europe to western North Africa, locations in the central North Atlantic Ocean, regions from eastern United States to the western North Atlantic Ocean and regions from the northeastern North Pacific Ocean to southwestern Alaska. For the month, the subtropical high over the Northwest Pacific was larger and stronger than normal, and its position was located in southward and westward of normal position.

Southern Hemisphere: For the month, in the 500hPa geopotential height anomaly field, positive anomalies above 4 dam covered the central South Pacific Ocean south to 20^oS, regions around Antarctica between 60^oS nearby and 80oS in Eastern Hemisphere and southwestern South Atlantic Ocean, with central values above 12 dam over locations. Meanwhile, negative anomalies below -4 dam covered locations south to Africa, southwestern Australia and locations south to Australia.

Tropical Features

Sea Surface Temperatures (SSTs): During November, positive SST anomalies dominated the western equatorial Pacific and regions between 130ºW~120ºW in the eastern equatorial Pacific, with central values above 0.5℃. Negative SST anomalies appeared in most of the central and eastern equatorial Pacific. Furthermore, comparing with the status of last month, SST anomalies declined in the central and eastern equatorial Pacific. In November, indices of NINO 1+2, NINO 3, NINO 4 and NINO Z were -0.4℃, -0.2℃, -0.3℃ and -0.3℃, with drops of 0.2℃, 0.1℃, 0.2℃ and 0.2℃ from last month, respectively, while NINO 3.4 index was -0.2℃ with a rise of 0.1℃ from last month.

Subsurface Temperatures: During November，negative sub-surface temperature anomalies enhanced at thermocline depth and its area expanded westward slightly, while positive anomalies weakened slightly in the western Pacific.

Warm Pools: During November, in terms of the western Pacific warm pool, its east boundary shrank slightly while both of its south and north boundaries expanded. Meanwhile the area of the Indian Ocean warm pool was above normal. The intensities of the two warm pools were all above normal.

Wind Field：For the month, at lower troposphere (850hPa), easterly anomalies prevailed over the regions west of 140ºW in the equatorial Pacific, with central values reaching 8m/s. At upper troposphere (200hPa), strong westerly anomalies covered the central and western equatorial Pacific.

Southern Oscillation: For the month, the Southern Oscillation Index (SOI) was 1.6, the same as that of last month.

Convections over the Tropics: During November, the anomalous outgoing longwave radiation (OLR) showed that convection was enhanced over Indonesia, and suppressed over the central equatorial Pacific. In the lower troposphere (850hPa) divergent wind field, a convergent center was over equator near 120ºE, and a divergent center was near 115ºW, 10ºS. At upper troposphere (200hPa), the corresponding divergent center was over equator near 110ºE, and the convergent center was near 120ºW, 20ºS.

ENSO Monitoring and Prediction

(1) During November, surface cold water covered the central and eastern equatorial Pacific, while warm water maintained in the western equatorial pacific.

(2) During November，negative sub-surface temperature anomalies enhanced at thermocline depth and its area expanded westward slightly.

(3) Southern Oscillation Index (SOI) was 1.6, the same as that of last month.

(4) For the month, at lower troposphere (850hPa), easterly anomalies prevailed over the regions west of 140ºW in the equatorial Pacific.

(5) Convection was enhanced over Indonesia, and suppressed over the central equatorial Pacific.

(6) Based on a majority of the model forecasts, ENSO-neutral conditions are expected to continue into early 2009.

During November, current tropical Pacific shows mainly ENSO-neutral conditions, with slightly cold phase status. Based on monitoring of recent atmospheric and oceanic conditions in the tropical Pacific and predictions of statistical and dynamic models, ENSO-neutral conditions are likely to continue into early 2009.