标准化降水蒸散指数在华北平原的适用性分析

目的]明确被广泛应用于农业气象研究的标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI)在华北平原的适用性,能够为区域减灾和可持续发展提供科学依据。方法]利用1961—2015年华北平原气象观测资料,使用Penman-monteith模型,计算了标准化降水蒸散量指数(SPEI),从数理统计、土壤湿度、农作物受灾面积等方面综合分析了SPEI在华北平原地区的适用性和对干旱的评价能力。结果](1)华北平原地区SPEI与10~20cm土壤相对湿度呈现显著正相关关系,SPEI值越大,气候越湿润,土壤湿度越大。(2)同一时间尺度下,不同地区SPEI与农作物受灾面积呈显著的正相关,相关系数由弱到强分别是河南省<山东省<河北省,而各地区的水稻种植面积由少到多依次为河北省<山东省<河南省,灌溉对潜在蒸散量计算结果干扰较大,SPEI对水稻种植区域的历史干旱识别不灵敏;(3)文章计算的SPEI能够与历史同时期发生的、厄尔尼诺引发的干旱事件很好地对应起来,华北平原地区整体呈不显著的干旱化趋势,各年代差异较大。结论]综合考虑了气温、风速和日照时数计算的SPEI,年尺度和季节尺度能够与典型站点典型年份的干旱事件很好地对应起来,与土壤水分监测数据和农作物灾情数据有显著的相关性,能够较好反映干旱严重程度,经过数理统计检验的SPEI适用于华北平原地区干湿变化的研究,但同时也要注意灌溉农业区的特殊水热状况,做出合理的分析调整。

APPLICABILITY ANALYSIS OF STANDARDIZED PRECIPITATION EVAPOTRANSPIRATION INDEX IN NORTH CHINA PLAIN

Clarifying the applicability of SPEI(Standardized Precipitation Evapotranspiration Index)in the North China Plain,which has been widely used in agricultural meteorological research,can provide scientific basis for regional disaster reduction and sustainable development.Using the data of meteorological and agricultural observations in the North China Plain from 1961 to 2015,the Penman-monteith model was used to calculate the SPEI,the comprehensive analysis of the applicability of SPEI in the North China Plain from the aspects of mathematical statistics,soil moisture,and the crops affected by drought.The main results were showed as follows:(1)The SPEI of the North China Plain had a significant positive correlation with the10cm to 20cm relative humidity of soil,the greater the SPEI,the more humid of the climate and the higher of the soil moisture.(2)At the same time scale,SPEI in different regions showed a significant positive correlation with the drought area of crops,and the correlation coefficients descending order ranged from weak to strong was Henan,Shandong,Hebei province,and the area of rice planted descending order from little to many was Hebei,Shandong,Henan.Irrigation interfered with the calculation results of potential evapotranspiration,and SPEI showed no sensitivity to drought monitoring in rice growing areas.(3)The SPEI calculated in this paper could correspond well with the drought events El Ni?o induced in the same period of history.The North China Plain area showed an insignificant trend of drought,however,with large differences in each decade.Considering the wind speed,temperature and sunshine hours,we calculated SPEI,the annual and seasonal scales can well correspond to the drought events in typical stations,and have significant correlations with soil moisture monitoring data and crops area affected by drought,and can better reflect the severity of drought.The SPEI,tested by mathematical statistics,is applicable to the study of dry and wet changes in the North China Plain.