陕西年降水量变化特征及周期分析

以1959-2009年陕西省各气象站逐旬降水资料为基础，采用墨西哥帽小波函数，线性趋势分析以及Mann-Kendall检验法，对陕西省51 a降水的时空分布特征及趋势进行分析，揭示了陕西省降水变化的多时间尺度的复杂结构，分析了不同时间尺度下降水序列变化的周期和突变点，并确定了主要周期。结果表明：（1）陕西省年降水量年际变化大且时空分布极不均匀，降水量从北部向南部递增，呈南多北少特征，大致上为纬向分布。陕北、关中、陕南年降水量多年平均值依次为279 mm、563 mm、840 mm。三大区域年均降水变化相对较为平稳，近51 a来，研究区内年均降水总体呈北部和南部略微下降，中部微弱上升的变化格局，线性倾向率分别为-5.110 mm/10 a、-3.758 mm/10 a、1.908 mm/10 a；（2）陕西省年均降水量有3～7 a，10～17 a，17～30 a周期，以中时间尺度10～17 a的少-多交替最为明显。在微观尺度上，陕北、关中、陕南地区的周期均表现得零乱且不显著。中观尺度，关中和陕南的降水周期比较显著，为10～17 a，陕北的降水周期表现得不十分规律。宏观尺度，陕北的降水周期为23～30 a，关中和陕南较为相似，为18～25 a；（3）Mann-Kendall检验发现1993年是陕西省年均降水量增加的一个显著突变点，2009年以后陕西省将处于多雨期。

Spatio-temporal distribution and temporal periodicity of annual precipitation in Shaanxi Province

Using precipitation data of every stations located in Shaanxi Province during 1959 to 2009，applying the statistical methods such as the Mexican hat wavelet function，linear trend analysis and Mann-Kendall method，the features and trend of the annul precipitation temporal and spatial distribution of 51 years in Shaanxi Province was analyzed. It is very important for us to strengthen the research of climate change law under the background of the global climate change，for which helps us raise the prediction ability of short-term climate，this paper took the Shaanxi Province as an example，analyzed the temporal and spatial distribution and trend of the annual precipitation in Shaanxi Province during 1959-2009，revealed the complex structure of annual precipitation in Shaanxi Province in multiple time scale，analyzed the period and mutation point of precipitation sequence in different time scale，and identified the main cycle. The result showed as follows：（1）In 1959-2009，average annual rainfall of Shaanxi Province had three periods which are 3-7 years，10-17 years，17-30 years and the 10-17 year is most obvious；（2）In the 1959-2009 time series，average annual precipitation change in Shaanxi Province was relatively stable；（3）The three regions with an average annual precipitation changes are relatively stable，from an average annual precipitation view，the northern and southern Shaanxi presented slightly down trend，the Guanzhong Plain showed a faint rising trend；（4）No significant mutations in northern Shaanxi，the significant mutations of Guanzhong Plain and southern Shaanxi respectively were in 1993 and 1991；（5）The evolution of rainfall in each area had three kinds of cycle rules. The micro scale that is 3 to 8 years behaved messy and was not significant. In medium scale，the precipitation cycle in Guanzhong Plain and southern Shaanxi was significant that is 10-17 years，precipitation cycle in northern Shaanxi showed irregularly. In macro scale，precipitation cycle of northern Shaanxi was 23-30 years，precipitation cycle of Guanzhong Plain was similar to southern Shaanxi’s，18 to 25 years.