变化环境下渭河流域农业干旱形成与发展过程的时空特征研究

Spatiotemporal characteristics of the formation and development of agricultural drought in Weihe river basin under changing environment

本研究采用3个月尺度的标准化降水指数(SPI3)表征农业干旱,对渭河流域的农业干旱发展过程包括干旱发生、结束及其转化期和持续时间的演变特征进行了研究。此外,通过交叉小波探究了太阳黑子和大气环流异常因子与SPI3指数之间的相关性。结果表明:(1)渭河流域农业干旱发生和结束的偏好季节均为夏季;(2)渭河流域干旱持续时间、发生和结束的转化期的趋势变化并不明显;渭河流域平均干旱持续时间约为3.6个月,明显长于渭河流域的干旱发生转化期和结束转化期;(3)太阳黑子对于渭河流域农业干旱发展过程的影响最为强烈,厄尔尼诺/南方涛动(ENSO)和北极涛动(AO)次之,太平洋10年涛动(PDO)最弱。研究结果有助于揭示农业干旱的形成机理,为建立可靠的农业干旱早期预警系统提供一定的科学依据。

In this paper, a 3-month standardized precipitation index (SPI3) was used as a representative index to identify agricultural drought. The evolution characteristics of agricultural drought in terms of drought onset, termination, and their transition periods as well as drought duration in Weihe River Basin were studied. In addition, the correlation between the anomalous factors of solar sunspots and atmospheric circulation and the SPI3 index was explored by cross-wavelet. The results showed that:(1) The preferred seasons of drought onset and recovery were summer in Weihe River Basin;The average drought duration in the whole basin was nearly 3.6 months, which was clearly longer than the average drought onset and termination transition periods.(2) The trend of drought in the Weihe River Basin during the drought period, the occurrence and the end of the transformation period are not obvious.(3) The sunspots have the strongest influence on the evolution of agricultural drought in Weihe River Basin, followed by ENSO and AO, while PDO is the weakest.