| 西北太平洋冷海温对东亚初夏大气环流影响的数值研究 |
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| 引用本文： | 袁佳双,郑庆林.西北太平洋冷海温对东亚初夏大气环流影响的数值研究[J].应用气象学报,2006,17(3):310-315. |
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| 作者姓名： | 袁佳双 郑庆林 |
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| 作者单位： | 1.中国气象科学研究院灾害天气国家重点实验室, 北京 100081 |
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| 基金项目： | 国家自然科学基金;甘肃省干旱气象科学研究项目;国家重点实验室基金 |
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| 摘 要： | 利用改进的NCAR CCM3气候模式, 研究了1992年西北太平洋持续冷海温对东亚初夏季节大气环流的影响。西北太平洋冷海温不利于初夏东亚南支西风急流季节性北移, 引起亚洲东部沿海低槽明显加深, 东亚大槽平均高度场降低了4.66 dagpm, 从而也不利于西太平洋副热带高压的西伸加强。西北太平洋冷海温还不利于我国大陆初夏温度场回升, 特别是引起我国东北地区近地面温度下降2~5 ℃, 是影响东北冷夏现象的重要原因之一。模拟结果表明, 1992年初夏江淮入梅期较常年偏晚, 降水异常偏少, 与紧邻东亚大陆的西北太平洋持续冷海温有关。
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| 关 键 词： | 西北太平洋 持续冷海温 季节转换 数值试验 |
| 收稿时间： | 2005-07-07 |
| 修稿时间： | 2006-01-04 |
Numerical Study on the Effects of Persistent Cold Sea Surface Temperature on the Northwest Pacific Ocean in Atmosphere Circulation During the Early Summer in East Asia |
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| Yuan Jianshuang,Zheng Qinglin.Numerical Study on the Effects of Persistent Cold Sea Surface Temperature on the Northwest Pacific Ocean in Atmosphere Circulation During the Early Summer in East Asia[J].Quarterly Journal of Applied Meteorology,2006,17(3):310-315. |
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| Authors: | Yuan Jianshuang Zheng Qinglin |
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| Affiliation: | 1.State Key Lab of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 1000812.Chinese Academy of Meteorological Sciences, Beijing 100081 |
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| Abstract: | Ocean as a large heat resource, its persistent sea surface temperature anomaly (SSTA) during the winter half year stirs upper air heating anomaly over it, contributing to atmospheric circulation variation in East Asia region in early summer. By employing the improved NCAR/CCM3 climate model, and designing two experiments which use different sea surface temperature anomaly (SSTA) over northwest Pacific ocean (6.66°—51.11°N, from East Asia western coast to about meridian) , using real monthly SSTA in Exp-A and climate mean SSTA in Exp-B, study is undertaken of the effects of cold SSTA on circulation transformation in the early summer in East Asia in 1992. This model considers well the influence of Tibetan Plateau topography, and the surface roughness length is improved in the context of new TIPEX data, thereby improvs the long term prediction and simulation ability over East Asia region. The investigations indicate that persistent cold SSTA from winter to early summer in 1992 over northwest Pacific ocean is significantly unfavorable for south branch westerly jet's northward seasonal shifting and Tibetan Plateau temperature gradient backspin from winter to summer, exhibiting the temperature decrease of 0—1 ℃ in the north side and increase of 1—2 ℃ in the south side of Tibetan Plateau at early summer, maintaining a west wind center of maximum speed of 5 m/s, 2 m/s on 200 hPa and 500 hPa respectively, resulting in the south branch westerly jet's persistence and enhancement. The cold SSTA in the northwest Pacific ocean reduces the heat release into the atmosphere, inducing the low trough's obuious deepening and the average geopotential height in east Asia dropping by 4.66 dagpm, therefore the cold air in the rear of the cold front invades the lower latitude area so the south branch of the front is southing, and is unfavorable for the west Pacific subtropical high's westwards move and strengthening. It also makes surface mean temperature at early summer decrease by 1—2 ℃ in central China or south China, especially decreasing by 2—5 ℃ at northeast China. Thus cold SSTA in northwest Pacific ocean is an important factor for colder summer in northeast China. The experiment results suggest that those phenomena occurring in early summer in 1992, such as the early or late arrival of the Meiyu in the Yangtze-Huaihe River Basins and scarce rainfalls in the rainy season, are in great relation to the cold SSTA in the close vicinity of East Asia land.The result shows that anomaly heating by SSTA in winter half year over northwest Pacific ocean plays an important role in the circulation variation in early summer. Persistent cold SSTA over northwest Pacific ocean can trigger changes of the temperature over Tibetan Plateau, and then of the westerly jet and long wave trough along Asias east coast, also of the sub-tropical high over western Pacific. Those changes are the main background of the planetary scale flow pattern transforming in North Hemisphere from winter to summer. And then, by influencing surface temperature, it affects the circulation transform in East Asia. |
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| Keywords: | the Northwest Pacific Ocean persistent cold SSTA season transition numerical simulation |
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