渭河流域气候变化及干湿状况时空分布分析

Climate change and spatiotemporal distribution of dry-wet status in Wei River basin

【目的】揭示渭河流域气候要素变化规律,明晰干湿状况分布及演变规律,为该流域减灾防灾决策提供支持。【方法】利用渭河流域21个气象站1960-2010年共51年的气象观测资料,采用FAO Penman-Monteith公式计算该流域各气象站的潜在蒸散量和干燥指数,通过气候倾向率、Mann-Kendall法、R/S法、小波分析、滑动平均等方法,对该区域气候要素、干燥指数的变化特征及干湿状况进行分析。【结果】(1)渭河流域51年来的降水量以1.69mm/年不显著线性趋势减少,潜在蒸散量以0.24mm/年不显著线性趋势增加,两者均存在17年和28年左右的变化周期;降水量与潜在蒸散量空间分布差异较明显,均呈东多西少、南多北少、由东南向西北递减的格局。(2)干燥指数以0.005/年不显著线性趋势增加,且增加趋势具有正的持续性;有8年和28年左右的干湿周期;干湿状况为东湿西干,南湿北干,呈现由东南向西北逐渐变干的格局。(3)预测该流域2010年后最湿润年份出现在2024年左右,最干燥年份出现在2019年左右。【结论】渭河流域多年来有降雨减少、潜在蒸散变大、逐渐变干的趋势,应采取应对措施减轻旱涝灾害及其不利影响。

【Objective】The variation of climate elements and distribution of dry-wet status in Wei River basin were studied to support decision-making in disaster prevention and reduction.【Method】Based on observation data at 21 meteorological stations in Wei River basin from 1960 to 2010for a total of 51 years,potential evaporation and aridity index were calculated using Penman-Monteith model.Variations in climatic elements,aridity index and dry-wet status were investigated by climatic trend rate,Mann-Kendall method,R/S method,wavelet analysis method and moving average method.【Result】(1)The precipitation decreased by 1.69 mm per year and the potential evapotranspiration increased by 0.24 mm per year.The changing periods of precipitation and potential evapotranspiration were 17 years and 28 years,respectively.The spatial distributions of precipitation and potential evapotranspiration were different,and they decreased from the southeast to the northwest of the basin.(2)The aridity index increased by 0.005 per year,and the increasing trend had a positive sustainability.The dry-wet status had periods of 8years and 28 years.The climate became drier from the southeast to the northwest.(3)The most humid year would occur in 2024,and the driest year will be 2019 in the basin.【Conclusion】The precipitation was decreasing,the potential evapotranspiration was increasing and the climate was becoming drier in recent years.Thus,measures should be taken to reduce the adverse effects of drought and waterlogging disasters.