基于Z指数的辽宁省气象干旱时空特性分析

Spatio-Temporal Characteristics of Meteorological Drought in Liaoning Province Based on Z Index

利用辽宁省21个气象站点1958年-2008年逐日降水观测资料,采用Z指数方法计算单站旱涝指标,在此基础上确定区域旱涝等级,从时间和空间两个方面对辽宁省近51年年际和春季气象干旱特征进行分析。研究结果表明:时间上,年际变化中,辽宁省旱涝交替发生,易发生连续性气象干旱,年际旱涝存在9年左右的显著周期,各个分区中辽西北地区干旱频次最大,辽南地区干旱频次最小;春季干旱变化与年际变化相似,春季旱涝存在3年左右的显著周期,各分区中辽西北与辽中地区春旱频次最大,而辽南地区春旱频次最小。空间上,年际干旱分布特征较集中,地域分布总体由西北向东南递减,其中重旱易发区为辽北和辽南,大旱易发区为辽西南部,偏旱易发区较分散;春旱分布特征较分散,其中重旱易发区为辽西北部,大旱易发区为辽北和辽南部分地区,而偏旱易发区较多且分散。研究结果与实际基本相符,可为辽宁省相关部门制定抗旱对策提供参考。

Based on the daily precipitation data from 21 meteorological stations in Liaoning province during 1958-2008, the drought and water logging indexes of single station were calculated by the method of normalized Z index in this paper. According to these data, the drought and flood grades were determined and the grade sequence was established. Besides, the annual and spring meteorological drought characteristics in recent 51 years were analyzed from perspectives of time and space. The conclusions are as follows： 1） From the point of view of time, the drought and water logging occur alternately in terms of inter-annual variation; the drought occurs on an average of two years, and the continuing meteorological drought occurs easily with more severe extent; there are nine years of primary cycle on Liaoning Province＇ s annual drought grade; drought frequency is the largest in northwest Liaoning province, and reaches minimum in southern part; spring drought is the most serious in terms of seasonal variation in Liaoning Province, with 18 years of drought out of 51 years. There are about three years of primary cycle on spring drought grade; drought frequency is largest in the middle and the north-west of Liaoning, and is smallest in southern part; 2） From the perspective of space, the distribution of inter-annual drought in Liaoning Province is more concentrated. Overall, it decreases from northwest to southeast. Northern and southern part are severe drought-prone areas, southwest is drought-prone area, and the partial drought-prone areas are more dispersed. The distribution of drought in spring is more dispersed, with north-western part is severe drought-prone area, northern and southern parts are drought-prone areas and the partial drought-prone areas are numerous and more dispersed. The research results correspond with the actual situation in the main, so they can provide a theoretical basis for relevant departments in Liaoning Province to develop appropriate drought countermeasures based on the regional drought characteristics.