黄土高原秋季气候对全球增暖的暖干化区域响应

Warming and Drought Response of Autumn Climate over Loess Plateau to Global Warm

利用69年（1937-2005年）的实测气候要素资料和各种统计方法，研究了黄土高原秋季气候对全球增暖的暖干化区域响应，结果表明：黄土高原秋季暖干化在四季中最为突出，降水（降水量、降水次数、连续性降水时量等）趋于减少、气温（平均、日最高、最低、季极端最高气温等）升高、蒸发量加大，暖干趋势明显；总低云量趋于减少、日照增多、地温上升等促进暖干发展。黄土高原秋季暖干化区域响应中全区一致性是其最主要的特征，高原中西部响应最敏感；在近70年中降水量演变出现2次明显转折，气温出现2次突变；降水异常与西太平洋副热带高压的夏季（JJA）东西位置、北太平洋海温异常联系紧密；年代际演变中降水量存在20～30年周期，气温周期不〈70年；预测未来20年内秋季气候将以暖湿为主。

To better look at the warming and drying response of autumn climate over Loess Plateau of China to globe warming, the climate changes over Loess Plateau of China have been analyzed using the climatic element in recent 69 years（from 1937 to 2005）. The results show that the warming and drying climate trend in autumn is significant in all seasons, which became warmer and drier in autumn over the Loess Plateau. So the total rainfall and low cloud trend were down; air temperature, evaporation, sunshine time, ground soil temperature were up. The mostly character of the warming-drying climate response were same consistent; the response sensitivity area was in the middle of the Plateau. In last 70 years （1937-2005）, the rainfall evolvement appear two inflexion points, and the temperature appear two abrupt changes. These changes have better relation with the subtropical high and the Qinghai-Tibet high. On evolvement of decade time scale, there is remarkable 20-30 year periods in rainfall, and no more than 70 years in the temperature.