山西省年降水分区及趋势特征

Annual Precipitation Zoning and Its Trend Characteristics in Shanxi Province

【目的】探明山西省年降水量的分区趋势特征,为当地农业生产及气候预测提供参考依据。【方法】以山西省内18个国家基本、基准气象站1981—2020年降水月值数据为基础,采用旋转经验正交函数(REOF)对年降水场进行分区分析。【结果】山西省年均降水量为386~700 mm,分布很不均匀,从东南部及东部偏北地区向西向北呈逐渐减少趋势。山西省年降水场可分为3个区,Ⅰ区位于山西省南部(南区),年均降水量为523 mm,最为丰富;Ⅱ区位于山西省北部(北区),年降水量降水最少,为433 mm;Ⅲ区位于山西省中部(中区),是Ⅰ区和Ⅱ区的过渡地带,年均降水量为517 mm。南区年降水量呈不显著减少趋势,趋势率为2.472 mm/10a,最近一次突变出现在2016年;北区年降水量呈显著增加趋势,趋势率为19.658 mm/10a,突变发生在2011年,且在2018年后降水量增加趋势更加明显;中区年降水量增加趋势不显著,趋势率为11.295 mm/10a,最近的突变发生于2019年。3个区域年降水量均存在多尺度周期变化特征,其中南区主周期为28年、22年、8年和13年;北区主周期为28年、18年和6年;中区主周期为28年和6年。【结论】山西省年降水量地区分布很不均衡,受地形影响较明显,各区降水发展趋势不一致,均具备多尺度周期特征,且各区第一主周期均为28年。

【Objective】The trend characteristics of annual precipitation zoning in Shanxi Province is explored to provide a reference for the local agricultural production and climate forecast.【Method】Based on the monthly precipitation data recorded by 18 national basic and benchmark meteorological stations in Shanxi Province during 1981—2020, the annual precipitation field zoning is analyzed by using rotating empirical orthogonal function(REOF).【Result】The mean annual precipitation is 386~700 mm with uneven distribution in Shanxi Province, decreasing gradually from Southeast and North-eastern area to the west and north. The annual precipitation field can be divided into three zones. Zone Ⅰ is located in Southern Shanxi(South zone) with the most abundant annual precipitation of 523 mm. Zone Ⅱ is located in Northern Shanxi(North zone) with the least annual precipitation of 433 mm.Zone Ⅲ is distributed in Central Shanxi(Central zone), which is the area between Zone Ⅰ and Zone Ⅱ, with the annual precipitation of 517 mm.The annual precipitation in South zone shows an insignificant decreasing trend with a trend rate of 2.472 mm/10 a, and the latest mutation appears in 2016;The annual precipitation in North zone shows a significant increasing trend with a trend rate of 19.658 mm/10 a, and the mutation occurs in 2011, and precipitation has increased obviously since 2018;The annual precipitation in Central zone has no obvious increasing trend, with a tend rate of 11.295 mm/10 a, and the latest mutation appears in 2019.There are multi-scale cycle variation characteristics of annual precipitation among the three zones, the main periods in South zone are 28 years, 22 years, 8 years and 13 years;the main periods in North zone are 28 years, 18 years and 6 years;the main periods in Central zone are 28 years and 6 years.【Conclusion】The distribution of annual precipitation zoning in Shanxi Province is unbalanced, which is affected by the terrain obviously. The precipitation development trend in each zone is inconsistent, and all have multi-scale cycle characteristics, and the first main cycle in each zone is 28 years.