中国北方农牧交错带气候变化特征及未来趋势

利用1951—2006年中国台站日平均观测资料对北方农牧带过去56a气候变化特征进行了分析，指出该农牧带年降水量具有明显的年际和年代际变化特征，近10a来呈明显的下降趋势；年平均气温在20世纪90年代前期变化幅度较小，1987年之后持续偏暖，与全球及中国温度变化趋势一致；降水和温度变化具有明显的季节和区域差异。在气候特征分析基础上，利用全球海气耦合模式嵌套区域气候模式在SRES A2排放情景下对未来30a（2001-2030年）的气候变化进行了预估，对照30a模式气候场（1961—1990年），分析了未来30a北方农牧交错带降水和温度变化的可能趋势，结果表明，未来该区平均地面气温持续升高，升温幅度达0．3℃，温度日较差将明显减小；年降水量呈增加趋势，但增加幅度较小，且降水变化具有明显的季节和地域差异；未来黄河上游地区干旱的威胁仍十分严峻。

Climate Change and Future Trends of the Farming-Grazing Zone in Northern China

By using Chinese station daily observation data, the climate change features of the farminggrazing zone in northern China in the past 56 years （1951--2006） have been analyzed. It is concluded that the annual precipitation presents obvious interannual and interdecadal variations in the zone with a remarkable decrease trend in the recent 10 years. The annual mean temperature has little change before 1990s,but becomes warmer persistently after 1987, which is consistent with the change trends in the globe and China. The changes of rainfall and temperature show the obvious seasonal and regional differences. Based on the above analyses, the future projection during 2001--2030 has been undertaken by the nested GCM（ global coupled model） and RCM（ regional climate model） under the IPCC SRES A2 emission scenario. Relative to the model climate field（ 1961--1990）, the possible change trends of rainfall and temperature in the zone in future 30 years have also been analyzed. The results indicate that the air surface temperature will keep on increasing in the whole region with annual mean increasing 0.3 ℃. Due to the minimum temperature increases larger than the maximum temperature, the daily range of temperature is expected to decrease in the future. Precipitation is expected to increase with less extent. Drought threaten in the up-reach of Huanghe River still might be very heavy in the future.