华北平原近45年农业气候资源变化特征分析

利用华北平原53个气象站1961—2005年逐日气温、降水资料，运用最小二乘法进行线性倾向估计，分析华北平原主要农业气候资源时间、空间变化趋势及其差异。结果表明：华北平原年≥0℃活动积温、5-10月≥10℃活动积温以及〈0℃负积温绝对值的变化与年平均气温的变化密切相关，20世纪60年代-70年代中期是热量贫乏阶段，70年代中期-90年代末是热量增加阶段，90年代末-2005年热量最丰富，但趋势表现为减少；华北北部和东部沿海热量增加趋势明显，中南部≥10℃活动积温呈减少趋势；华北平原全年、夏季降水量减少趋势不显著，但年际间变化增大，多年来降水偏少，2003—2005年的降水量增加；华北平原降水量分配在南北之间、沿海与内陆之间趋于平均，夏季表现尤为明显。

Analysis of Changing Characteristics of Agricultural Climate Resources Over Last 45 Years in North China Plain

The temporal and spatial tendency, differences of agricultural climate resources in the North China Plain was analyzed by using linear-trend estimate, based on the daily air temperature and precipitation of 53 meteorological stations from 1961 to 2005 in the North China Plain. The result indicated that the inter-annual change between the annual accumulated temperature ≥ 0℃ ,the accumulated temperature ≥ 10℃ from May to October, the absolute value of annual accumulated temperature 〈 0℃ and the air temperature existed a corresponding relationship in the whole North China Plain. There was a poor period of heat before the middle of 1970s, the heat was increasing from the 1970s to the end of 1990s, and it was quite abundant in the last 15 years. The heat increased greatly in the north of the North China Plain and on the east coast of Shandong. But the accumulated temperature higher than 10℃ during the crop growing season decreased in the central south of the North China Plain. The annual precipitation and precipitation in summer decreased faintly, and the fluctuation of precipitation inter-annual was intensified. Differently, the annual precipitation was increased in the last three years （2003 -2005）. The results also showed that the precipitation differences between the south part （coastal area） and the north part （inland） was getting smaller, especially in summer.