不同气候平均值对气候评价业务的影响*

使用新疆99个气象站年、季、月气温、降水要素1981—2010年平均值和1971—2000年平均值资料,从区域平均和空间分布两方面对新旧2个气候平均值进行对比分析。结果表明:年气温、降水,各区域均增加;气温增幅0.3~0.4℃,北疆、天山山区略大于南疆;降水增幅4.7%~8.9%,南疆略大于北疆、天山山区。季气温、降水,各区域均增加;气温北疆四季变化较天山山区、南疆更明显,降水南、北疆季节差异较天山山区更大。2、3、11月的月气温增幅较大,4—10月较小;月气温差值空间型分为四型:全疆一致增加型、全疆大部增加型、北疆增加南疆减少型、北疆减少南疆增加型。1、3、7、11月的月降水增幅较大;月降水差值空间型分为两型:全疆大部增加型和北疆增加南疆减少型。气候平均值改变后,气温、降水等级整体由正距平向负距平方向调整,一些过去的气候评价结果在长序列评价中需要重新考虑。

Difference of Normals and Its Influence on Climate Assessment in Xinjiang

A comparison was made between two climate normals from 1981 to 2010 and 1971 to 2000 of 99 meteorological stations in Xinjiang. The results show that the new normal of yearly and seasonal temperature and precipitation increase in all parts of Xinjiang, while the new normal of monthly increase in most of region and time. The increase of monthly temperature and is much more in February, March, November than that in April to October. There are 4 types of distribution of difference of monthly temperature, i.e. coincident increase in all the region, increase in most parts of region, increase in North while decrease in South, increase in South while decrease in North. The increase of monthly precipitation is much more in January, March, July, November than that in other time. There are 2 types of distribution of difference of monthly precipitation, i.e. increase in most parts of region and increase in South while decrease in North. After normal changes, the grades of temperature and precipitation adjusted from positive to negative so that some past conclusions needed to be reconsidered.