Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Based on hourly precipitation observation data from 340 meteorological stations in Gansu Province from April to October 2013 to 2022, the refined evolution characteristics of warm season precipitation in Gansu Province on a diurnal variation scale were revealed. Discussions and analyses were conducted in different regions, providing a scientific reference for the study of extreme precipitation events in Gansu. The results show the following: (1) the daily peak of precipitation and precipitation intensity in the warm season in Gansu mainly occurs between 10:00 and 13:00, the daily peak of precipitation frequency primarily occurs between 22:00 and 01:00 at night, and the daily precipitation variation has obvious seasonal differences. There is a relatively concentrated distribution of autumn rain in the central and southern parts of Gansu. (2) The diurnal variation of precipitation has distinct regional characteristics. Precipitation in the Qilian Mountains and the plateau slopes of central Gansu mainly occurs during the day, with intense precipitation dominating around noon, marking the peak of daytime precipitation. Conversely, in western Hexi, the peak and frequency of daily precipitation generally occur at night, with occasional sudden heavy rainfall between 18:00 and 21:00. In southeast and eastern Gansu, the precipitation is nonuniformly distributed; nighttime rain is common due to the frequency of precipitation peaks during the night, but strong precipitation periods tend to occur in the afternoon and morning, respectively. (3) The precipitation characteristics of different durations are different. For short-term precipitation events with a duration of 6 h and below, the daily variation of precipitation is mostly“bimodal type.”Long-term precipitation events lasting more than 6 h are“unimodal type”and primarily begin in the evening, reach their peak at night, and end at noon.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： This study used the Sen+M-K trend analysis, the gravity center movement model, the standardizedregression coefficient, and the spatial clustering methods to reveal the spatial characteristics of the variation,trends, and movement of dust days of various types and the contribution rate of their influencing factors in theTarim Basin based on the annual data of 32 meteorological stations between 1964 and 2022. The resultsindicated: (1) Floating dust, followed by blowing sand and sandstorms, dominate the Tarim Basin, showing aspatial distribution pattern of more in the south and less in the north, and the dust days of various types showsignificantly decreasing trends. (2) The gravity centers of dust days of various types in the Tarim Basin tended tomove southeast, and the gravity center of sandstorm days moved the most. (3) Warmer temperatures, lower windspeeds, and fewer gale days were the main factors in the decreased dust days in the Tarim Basin, whereasprecipitation had the least influence. (4) The high contribution rates of precipitation to dust days are clustered inthe western part of the Tarim Basin, mean temperature and mean maximum temperature in the southern andwestern parts, respectively, and gale days and mean wind speed in the northwestern and southeastern parts,respectively. This study’s results can provide a scientific basis for developing regionally applicable windbreakingand sand-fixing measures in the Tarim Basin.
Subjects: Geosciences >> Geography submitted time 2023-08-01 Cooperative journals: 《干旱区地理》
Abstract：选取19602020年中亚126个气象站点逐日降水数据，基于RClimDex模型计算中亚8种极端降水指数，利用线性回归分析、Mann-Kendall法分析、相关性分析、小波变换和重标极差（R/S）分析，探究中亚极端降水事件特征。结果表明：（1） 近60 a中亚极端降水事件频率和强度均明显增加，表征降水强度（SDII）变化倾向率为0.02 mmd-1(10a) 1。极端降水量指数中，强降水量（R95p）、单日最大降水量（Rx1day）、连续5 d最大降水量（Rx5day）、年总降水量（PRCPTOT）的变化倾向率分别为1.93 mm(10a)-1、0.24 mm(10a)-1、0.66 mm(10a)-1和0.73 mm(10a)-1。在极端降水日指数中，中雨日数（R10）、持续干燥日数（CDD）、持续湿润日数（CWD）变化倾向率分别为0.02 d(10a)-1、-0.65 d(10a)-1和0.08 d(10a)-1。极端降水存在明显的空间差异性和高海拔依赖性，高原和山区附近极端降水事件频发。中亚极端降水周期特征为多峰谱型，具有准5 a短周期振荡、6~9 a中周期振荡和10~15 a长周期振荡。（2） 极端降水指数与年总降水量具有良好的相关性，CWD对年总降水的贡献最大；太平洋年代际振荡（PDO）和北大西洋年代际振荡（AMO）对极端降水事件具有明显正相关性。R/S分析表明该地区极端降水特征未来持续可能性较大。研究结果可为中亚极端气候预测、自然环境保护、防灾减灾工作等提供科学依据。
Subjects: Geosciences >> Geography submitted time 2020-11-24 Cooperative journals: 《干旱区地理》
Abstract： 利用新疆1954—2018年雪灾资料分析其灾害时空特征，时间上雪灾灾损强度在90年代后出现明显加大，2010年出现跃增特点，空间上雪灾灾损强度新疆西部多于东部，北部多于南部，山区多于盆地或平原。用雪灾出现次数、房屋倒塌间数、牲畜棚圈倒塌间数、损坏大棚数、死亡牲畜数、受灾面积、经济损失等多指标综合分析法来客观构建灾损指数，符合[Γ分布的灾损指数结合F分布函数能客观的描绘出雪灾等级，分为一般、较重、严重、特重4个等级。根据构建的雪灾等级，发现新疆雪灾特重灾区集中在天山山区及其以北地区，南疆仅有喀什地区为特重灾区。
Subjects: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract： 风云三号D星(FY-3 D)是我国新一代极轨气象卫星，中分辨率光谱成像仪II ( MERSI- II )是其携带的核心传感器之一，MERSI- }实现了云、气溶胶、水汽、陆地表面特性、海洋水色等大气、陆地、海洋参量的高精度定量反演。选取2018年大8月无云时相的FY-3 D/MERSI- II数据对天山中段终年积雪进行归一化积雪指数(vDSI)的计算。结合高分辨率Landsat-8影像，利用混淆矩阵对FY-3D/MERSI- II数据计算结果与同期MODIS日积雪产品数据MOD10A1进行精度对比分析。结果表明:FY-3 D/MERSI- II图像平均总体精度为0. 855 , MOD10A1图像平均总体精度为0. 820 ,FY-3 D/MERSI- }积雪覆盖提取平均总体精度比MOD10A1积雪覆盖提取平均总体精度高0. 035FY-3 D/MERSI- II的K内>pa系数平均值为0. 659 , MOD10A1的K句>pa系数平均值为0. 558 , FY-3 D/MERSI- II的K内>pa系数平均值大于MOD10A1的K内>pa系数平均值。故FY-3 D/MERSI- II数据提取积雪覆盖面积精度更高，更接近高分辨率Landsat-8影像目视解译结果。
Subjects: Geosciences >> Geography submitted time 2020-01-06 Cooperative journals: 《干旱区地理》
Abstract：利用2010—2017年1~12月新疆喀什地区10个气象站逐小时降水资料，分析统计喀什地区近8 a降雨雪（以下统称降水）日变化特征。结果表明：（1） 喀什地区全年降水量和降水频次日变化存在明显的波动，总体上呈现“正弦波”一峰一谷特征，降水量峰值出现在03:00（北京时，下同），谷值出现在18:00；降水频次峰值出现在04:00，谷值出现在18:00；两者峰谷值出现时间接近。（2） 2010—2017年喀什地区全年降水量和降水频次呈明显的增加趋势；而降水强度年际变化趋于平缓，无明显变化。（3） 降水强度日变化趋势与降水量、降水频次并不存在一致性。（4） 喀什地区全年降水主要以短时段降水为主，其中，持续1 h降水次数为最大值，但降水量和贡献率最大值却同出现在2 h和6 h持续降水中。全年降水主要以后半夜和上午开始的降水过程为主导，且仍主要为短时段降水。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-10 Cooperative journals: 《干旱区研究》
Abstract：针对哈萨克斯坦阿尔泰山南坡西伯利亚云杉（Picea obovata）和西伯利亚落叶松（Larix sibirica）开展树轮研究，建立树轮年表，计算年平均树轮宽度值和年平均断面积生长量（BAI），并分析在1988年发生升温突变前后，这2个树种树轮宽度指数变化趋势，及其树木径向生长对气候因子的响应。结果表明：在升温突变前后，2个树种树轮宽度指数变化趋势一致。但是，在升温突变后，其变化趋势均由不显著增加转为显著下降。即树木径向生长减缓；升温突变后，2个树种树木径向生长对降水的响应有所减弱，而对气温的响应有所增强，并且发生了树轮指数和气候因子间相关性“正负转换”的情况。
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