青海省干旱指数时空变化特征与气候指数的关系

基于青海省29个气象台站1961-2013年的实测气象数据,应用Penman-Monteith模型、气候倾向率、空间分析、交叉小波和相干小波变换等方法分析青海省干旱指数的时空变化、影响因素及其与北极涛动(AO)和厄尔尼诺-南方涛动(ENSO)等气候指数的相互关系。结果表明,近53年来,青海省多年平均干旱指数为0.49,整体呈现出波动降低趋势,其线性降低速率为-0.03·10 a-1 (α=0.01),表明青海省气候有变湿的趋势。研究区年内干旱指数呈现出先减小后增加的趋势,最小值出现在8月,最大值出现在12月。最高值出现在西北部的茫崖镇与中北部的格尔木市和诺木洪乡,最低值出现在中南部的曲麻莱县和东南部的久治县。青海省干旱指数与日照时数(P<0.01)和风速(P<0.05)总体呈现显著的正相关关系,而与温度和降水呈显著负相关关系(P<0.05)。此外,研究区干旱指数与北极涛动(AO)和厄尔尼诺-南方涛动(ENSO)指数存在多尺度的显著相关性(a=0.05)。

Spatial and temporal characteristics of aridity index and association with AO and ENSO in Qinghai Province

This study were used the methods of climate tendency rate, spatial analysis, Penman-Monteith model, the temporal-spatial variations, cross wavelet and wavelet coherence to analyze the spatial and temporal variations of AI (aridity index), influencing factors, and the relationship of the AI with AO (Arctic Oscillation) and ENSO (El Nino-Southern Oscillation), based on the data of 29 meteorological stations in Qinghai Province during the period of 1961-2013. The results showed that the average of AI was 0.49 for many years. The trend of AI fluctuantly reduced in the past 53 years. The average of AI linearly decreased at the rate of -0.03·10 a-1 (α=0.01) over the study area, which means the climate gradually changes to moist in Qinghai Province. The maximum value and minimum value of AI appeared in December and August, respectively, which showed that the average of AI increased firstly then reduced within a year. The maximum of the AI appeared in northwest of Mangai County and north-central of Golmud City and Nuomuhong Town, and the minimum of AI appeared in southern-central of Maqulai County and Jiuzhi County. The average of AI had significantly positive correlation to sunshine time (P<0.01) and wind velocity (P<0.05) in Qinghai Province. At the same time,the average of AI has negative correlation with the temperature, precipitation and relative humidity. In addition, the average of AI is multi-scale significant correlation to AO and ENS in this study (a=0.05).