Subjects: Geosciences >> Geography submitted time 2024-05-31 Cooperative journals: 《干旱区地理》
Abstract：利用1961—2020年宁夏20个国家气象站气象观测资料，结合近40 a宁夏社会经济统计数据，建立宁夏干旱过程事件指标，并基于灾害风险评估理论建立宁夏年代际干旱灾害风险评估模型，分析宁夏干旱事件和主要农作物干旱灾害风险的年代际变化特征和区域差异性，并探讨造成区域农作物年代际风险变化的可能影响因素。结果表明：（1）近60 a宁夏干旱事件的累积效应、持续时间以及强度指标具有明显的年代际变化特征，宁夏中北部和南部山区分别在1980年和2010年前后出现趋势和均值的突变；干旱事件指标及致灾危险性指标大值区空间范围均呈现出增加-减少-增加-减少的变化特征。（2）20世纪80年代以来，宁夏不同地区玉米干旱灾害风险等级依次为引黄灌区>中部干旱带>南部山区，受玉米种植面积不断扩大和国内生产总值（GDP）持续增加影响，在中南部地区其干旱风险呈逐年代际增大趋势；小麦干旱灾害风险增加幅度为中部干旱带>南部山区>引黄灌区，致灾危险性、小麦种植面积及GDP等级较高是2010s中部干旱带部分地区干旱风险增大的主要原因。（3）面对未来宁夏中南部地区水资源短缺和灌溉用水不足的挑战，建议通过提高人工增雨能力、开发种植品种、退耕或移民等措施，减少干旱致灾危险性、孕灾环境脆弱性和承灾体暴露度，从而降低当地玉米和小麦的干旱灾害风险等级。研究结果可为地方科学规划农业生产、高效利用水资源、抗旱救灾等提供科学理论依据，促进宁夏黄河流域生态保护和高质量发展先行区建设。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： Based on daily temperature observation data and reanalysis data of the geopotential height, sea levelpressure, and wind field from 1961 to 2020, the characteristics of spatial and temporal change of cold waves,strong cold waves, and exceptionally strong cold waves lasting 24 h, 48 h, and 72 h were studied in Ningxia overthe past 60 years. The causes of atmospheric circulation anomalies of cold waves were also revealed. The resultsshow the following: (1) In the past 60 years, cold waves of different intensities and different durations in Ningxiaconsistently showed the distribution characteristics of“shifting eastwards and northwards.”(2) The cumulativefrequencies of cold waves, strong cold waves, and exceptionally strong cold waves in the region accounted for71.7%, 22.6%, and 5.7% of the total annual cold wave frequencies, respectively, among which cold wavesdominated by process lasting 24 h and 48 h. The proportions of various durations for strong cold waves andexceptionally strong cold waves were equivalent. They mainly occured in October to April, during which theaccumulated cold waves, strong cold waves, and exceptionally strong cold waves in the region accounted for99%, 98%, and 95% of those throughout the year, and there was a decreasing trend from January to April andincreasing trend from October to December. (3) In the past 60 years, the cold waves, strong cold waves, andexceptionally strong cold waves have been decreasing at a rate of 4.5, 2.8, and 0.18 per station every 10 years,respectively. Among them, the frequencies of waves of 24 h and 48 h as short durations were decreasing, but thatof waves of 72 h as a long duration was decreasing. All types of cold waves decreased from the 1960s to the1990s, reaching a minimum in the 1990s and increasing since the 2000s, with a sudden change around 1990. (4)Under the influence of global warming, the atmospheric circulation showed completely the opposite distributioncharacteristics between before and after the sudden change of cold waves in Ningxia. The key systemsinfluencing cold waves in Ningxia are consistent. When the blocking high pressure in the Ural Mountains wasstronger, the East Asian trough was deeper, the west Pacific subtropical high was weaker, the western side ofLake Baikal was dominated by cyclonic circulation, and cold high pressure at the ground was active, this wasconducive to the southward movement of cold air in middle and high latitudes, and more cold waves in Ningxia.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2021-09-14 Cooperative journals: 《干旱区研究》
Abstract：选取近57 宁夏20个气象站夏季逐日最高气温、NCEP/NCR再分析及北极海冰资料，利用气候统计诊断方法，分析了宁夏夏季极端高温的气候异常特征及其与北极海冰的联系。结果表明：宁夏夏季极端高温总强度、事件频次及最长持续日数自1961年以来总体呈增加趋势，尤其1990s后期至2000s中期是年代际增加最快的时段；极端高温总强度偏强年，宁夏处于500 hP位势高度场正中心的南边，北边冷空气不易入侵，有利于宁夏夏季极端高温偏强；前期春季格陵兰海、巴伦支海、喀拉海地区海冰密集度偏高时，激发500 hP位势高度距平场上出现正负相间的波列自北向南、自西向东往欧亚地区稳定传播，造成乌拉尔山高压脊减弱，使得欧亚中高纬地区以纬向环流为主，导致宁夏夏季极端高温强度偏强。本研究结果旨在为宁夏夏季极端高温预测提供理论依据。
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