温室效应引起的中国区域气候变化的数值模拟Ⅱ:中国区域气候的可能变化

CLIMATE CHANGE DUE TO GREENHOUSE EFFECTS IN CHINA AS SIMULATED BY A REGIONAL CLIMATE MODEL PART Ⅱ: CLIMATE CHANGE

  • 摘要: 使用RegCM2区域气候模式单向嵌套澳大利亚CSIRO R21L9全球海-气耦合模式,进行了温室气体CO2加倍对中国气候变化影响的数值试验研究。该文为第2部分,对敏感性试验结果进行的分析。分析表明:由于温室效应,中国区域的地面气温特别是在冬季和北方将有明显升高,区域年平均的升高值为2.5℃;同时区域内日最高和最低气温将明显上升,日较差将减小。结果还表明,在CO2倍增条件下,中国区域降水将呈增加趋势,区域年平均的增加值为12%;以夏季的增加率最大,其次为冬季。中国汛期降水将呈现出“三类雨型”出现频率增多的趋势。南方的大雨日数将有所增加。此外,生成和影响中国的台风数目也将有所增加。温室气体的增加同时对环流场产生影响,如导致500 hPa高度场的升高。

     

    Abstract: Impacts of greenhouse effects(2×CO2)on climate change over China as simulated by a regional climate model have been investigated. The model was based on RegCM2 and is nested in one-way mode within a global coupled atmosphere-ocean model (CSIRO R21L9 AOGCM).Two mufti-year simulations, the control run with normal CO2 concentration and sensitive run with doubled CO2 concentration are conducted. As Part Ⅱ of the publications, results of the sensitive runs are analyzed in the paper. With a brief analysis of the sensitive experiment by CSIRO R21L9,simulation by RegCM2 are analyzed in detail. Results of RegCM2 show a remarkably warming over China with a range from 2.2℃ in southern China to 2.8℃ in northern China due to greenhouse effect. The annual area mean temperature increase is 2.5℃.The greatest warming is simulated in winter season by the model. Daily maximum and minimum temperatures increase also over China, which leads to much more hot spell days in summer and less cold spell days in winter. Precipitation increases in all seasons of the year, with the highest value found in summer. Annual mean precipitation increases significantly in western China, parts of the area in south of the Yangtz River and northern part of Northeast China,while a decrease in the area from southern part of Northeast China to North China is simulated. The annual area averaged increase is 12%.As for the operational short-term climate prediction for flood season precipitation in China, frequency of "the third type of rain pattern" might increase. Number of heavy rain days is found noticeably increasing in South China. Tropical storms affecting and landing over China tend to increase due to greenhouse effects. Analysis on the simulation of circulation pattern shows that due to the greenhouse effect, the 500 hPa height in East Asia might increase significantly.

     

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