基于标准降水指标的新疆干旱特征演变

SPI-based Drought Variations in Xinjiang, China

  • 摘要: 运用标准降水指标 (Standardized Precipitation Index, SPI) 对新疆地区53个雨量站1957—2009年日降水量资料进行全面分析,研究了不同干旱等级发生概率的空间分布变化规律。同时,采用Mann-Kendall趋势检验法分析了各月份标准降水指标值、干旱强度和干旱历时的变化趋势,探讨了新疆地区干旱时空演变特征。结果表明:北疆易发生中等及以上干旱,而南疆易发生轻度干旱。总的来说,北疆干旱强度有下降的趋势,干旱历时趋于缩短,南疆南部干旱强度和干旱历时有轻微上升,东疆中部干旱情况显著恶化。具体来说,北疆冬季干旱程度有减弱趋势,而对于农业生产较重要的春、夏、秋季,西部干旱加剧;南疆夏季干旱有减弱趋势;东疆中部四季干旱程度有轻微加剧趋势。

     

    Abstract: Daily precipitation data at 53 stations during 1957—2009 in Xinjiang are analyzed based on Standardized Precipitation Index (SPI) technique with the aim to investigate the spatial-temporal patterns of drought events. The Mann-Kendall trend test is used to detect the trends of monthly SPI values, drought intensity and drought duration. Pre-whitening technique is applied before the Mann-Kendall trend test to eliminate the autocorrelation within the precipitation series.According to the results, the frequency of mild drought in North Xinjiang is less than the theoretical frequency, while frequencies of moderate, severe and extreme droughts are higher than the theoretical ones. The statistical condition of drought events in South Xinjiang is to the opposite. Although the drought disaster in Xinjiang is abating in general, the trend varies in different areas. The decreasing of drought in North Xinjiang mainly happens in winter. However, in spring, summer and autumn, the decreasing is insignificant and has obvious influences on agriculture. As the agricultural water demand is increasing tremendously recently, this insignificant decreasing of drought hardly compensate the shortage of water demand. As a result, this change may be not beneficial to agriculture. The abating of drought in South Xinjiang mostly occurs in summer, while the drought in the south part of South Xinjiang is aggravating. The drought in East Xinjiang slightly aggravates. In North Xinjiang, both the intensity and duration of drought have decreasing trends. The intensity and duration of drought in South Xinjiang are both slightly increasing. In the middle part of East Xinjiang, the intensity and duration of drought are both significantly increasing. These results provide theoretical and practical merits for better understanding of variations of drought, monitoring of drought, and mitigating the losses of drought disaster.

     

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