【摘要】 选用河套及其邻近地区58个气象站建站至2003年历年各月降水资料,分析了河套及其邻近地区降水的气候变化特征。结果表明:该地区降水量总体上是东南多、西北少,等雨量线呈东北—西南走向。降水量最小的地方在河套地区西北部,最大的地方在河套地区东南部。由于受下垫面地理特征、蒙古高压和青藏高原东北侧反气旋(小高压)的影响,降水梯度西南大于东北。降水变化的整体性较好,但也存在南北差异。近40年来河套地区降水西北部和东南部分别以2%/10a和3%/10a的速度在减少,但20世纪90年代末,21世纪初降水又有回升趋势。进一步研究表明,河套及其邻近地区降水异常与欧亚雪盖面积变化有关,当秋季欧亚雪盖面积增大,则次年河套及其邻近地区降水增多,反之亦然。更多还原

【Abstract】 The precipitation variational characteristics of the Hetao area has been analyzed by using the monthly precipition data of 58 meteorologic stations in the Hetao and its vicinity area from the beginning to 2003.The result shows that the precipitation is more in the southeast and less in northwest as a whole,and isopluvial present the trend of the northeast-southwest.the region of the least precipitation is the northwest of Hetao area,while the region of the most precipitation is the southeast.Because of the effect of geography characteristic and Mongolia high pressure and anticyclone of the northeast of Qinghai-Xizang Plateau,the grads of precipitation is greater in the southwest than in the northeast.The precipitation has a better coherence in space,but it has the difference between the south and the north of Hetao area.In recent 40 years the precipitation of the northwest of Hetao area is decreasing by 2%/10a,and the precipitation of the southeast of Hetao area is decreasing by 3%/10a,but at the end of 1990′s and the begin of 21 centuries the precipitation of the southeast turn round.The further research indicate: in the Hetao and its vicinity area the precipitation have an osculatory relation with Eurasia snow area. When Eurasia snow area increase in autumn,the precipitation in the Hetao and its vicinity area will increase in the following year,vice versa.更多还原