近56年青海省≥0℃热量资源的时空变化特征

Spatial and temporal variation of above 0℃ thermal resources in last 56 years in Qinghai Province

利用青海省44个气象站1960～2015年的逐日平均气温资料,采用线性倾向估计、Mann-kendall突变检验以及反距离权重插值(IDW)方法,对青海省近56 a日平均气温稳定≥0℃的积温、持续天数、初日、终日的时空变化规律进行了分析。结果表明:(1)近56 a青海省≥0℃的积温和持续天数分别以64.38℃·10a-1和3.25 d·10a-1的倾向率呈显著增加趋势,二者分别于1998年、1997年发生了突变。二者主要受初日提前和终日推迟的共同影响。(2)≥0℃积温和持续天数大体上均呈现由西南向东北逐渐增加的趋势,高值区主要分布在东部农业区和柴达木地区,低值区主要分布在三江源区西部。(3)与20世纪60年代相比,21世纪青海省≥0℃积温段Ⅱ(500～1 500℃)面积减小了14.06%;≥0℃积温段Ⅳ(2 000～3 000℃)面积增加了16.34%。(4)随着气候变暖,1 500℃等值线呈现出整体向高海拔扩张和向低纬度南移的趋势,且呈显著向西向南的移动趋势。

The daily temperature data of 1960 to 2015 from 44 meteorological stations in Qinghai Province were used to study the temporal and spatial variation of steadily accumulated temperature(≥0℃),lasting days,the beginning and ending dates by using the methods of linear trend estimation,Mann-kendall,and Inverse Distance Weighting(IDW). The results showed:(1) In last 56 years,the accumulated temperature steadily above0℃ and its lasting days were increased at rates of 64.38℃ ·10a-1and 3.25 d·10a-1,and them abrupt change ccurred in 1998,1997,respectively. This phenomenon was mainly due to advanced start date and the delayed end date. Furthermore, the delaying of end date was more influential than the advanced start date.(2) The accumulated temperature steadily above 0℃ and its lasting days increased gradually from the southwestern region to the northeastern region in Qinghai. The areas with high values of the accumulated temperature steadily above 0℃and the lasting days were mainly in the eastern agricultural region and Qaidam Basin,areas with low values were in the west of Three-River Headwaters Region.(3) Compared with 1960 s,the areas in the section Ⅱ(500 ~1 500℃) of accumulated temperature above 0℃ decreased by 14.06% in the early 21 stcentury while the areas in the section Ⅳ(2 000 ~ 3 000℃) increased by 16.34%.(4) Due to global warming,1 500℃ isopleth expanded to high altitude and low latitude,and a significant shifting trend toward the south and the west.