Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Precipitation acts as a crucial supply for mountain glaciers, and its water vapor source closely correlates to the amount of precipitation. This study focuses on the modern glacier distribution area of Ulugh Muztagh in the eastern Kunlun Mountains, analyzing water vapor sources in the region from 2005 to 2022 using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and the Global Data Assimilation System (GDAS). Employing backward trajectory analysis, we reveal the source and regularity of water vapor in the Ulugh Muztagh region and discuss its seasonal changes. The results show that the water vapor source in the Ulugh Muztagh area mainly extends to the Eurasian interior along the midlatitude westerly belt and is divided into three routes entering the Qinghai-Tibet Plateau from the Tianshan Mountains, the Pamir Plateau, and over the high-altitude stratosphere. On the Qinghai-Tibet Plateau, water vapor from the Indian Ocean either moves northward over the Himalayas or turns northwestward to merge with the westerly circulation into the plateau’s hinterland. Land-source water vapor, entering from the Pamir Plateau and Tianshan Mountains, accounts for 62.52% of the total water vapor in the Ulugh Muztagh area. Meanwhile, sea source water vapor, comprising high-altitude water vapor from the westerly belt (Atlantic water vapor) and the Indian Ocean, accounts for 37.48% of the total water vapor. Notably, we find that the proportion of water vapor from the sea source has increased steadily over recent decades. Analyzing multiyear seasonal averages for water vapor, we find a notably high proportion of locally recycled water vapor in the summer, comprising 22.64% of the total. This study’s outcomes offer valuable insights into the water cycle dynamics of the Ulugh Muztagh area in the East Kunlun Mountains.
Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： Based on precipitation and soil water isotope data at different elevations in the north and south mountains of Lanzhou from April to October 2018, the lc-excess method and the lc-excess equilibrium equation were used to qualitatively and quantitatively analyze the soil water infiltration process in this area. The infiltration process of soil water, indicated by the soil water lc-excess value, was verified by correlation analysis and single factor analysis. The results showed that there are obvious variations in soil water content in the study area on a monthly scale and at different depths, with loss dominating from April to June and accumulation dominating from July to September. The soil water content in the high altitude areas was found to be greater than that in the low altitude areas, and the soil water content in the north mountains was found to be greater than that in the south mountains. Stable isotopes of soil water at each sampling site we found to be most depleted from August to September. At increasing soil depth, soil water isotopes showed a trend of gradual depletion and stabilization. The soil water lc-excess results showed that the piston flow mode and the priority flow mode coexist in the infiltration and recharge process of soil water in the study area. The priority flow signal appeared at all sampling sites from July to August. The contribution of the preferred flow pattern to deep soil water was higher at the low elevation sampling sites than at the high elevation sampling sites. The soil water content and soil water lc-excess were found to be positively correlated. The monthly scale and depth of soil water lc-excess were not significantly different between the north and south mountain, indicating that the infiltration and recharge patterns of soil water in the north and south mountains are the same, and that both are dominated by the piston flow infiltration pattern of precipitation recharge. However, in the south mountains, where there is greater vegetation cover, the preferential flow pattern signal appeared more often, especially in July and August, when precipitation is concentrated. Based on the soil water infiltration and replenishment processes in the north and south mountains, it the selection of salt- and drought- tolerant, shallow- rooted shrubs and perennial grasses is recommended for the north mountains, while reasonable irrigation is recommended in the south mountains during the plant growing season (from April to June). The results of this study provide a theoretical reference for understanding the hydrological process in the north and south mountains of Lanzhou.
Subjects: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract： 基于2012年6-8月的实测水汽同位素数据及相关气象数据，对黑河中游夏季昼夜的同位素基本特征、水汽来源方向及潜在蒸发源地进行了研究。结果表明:空气水汽线斜率白天大于夜晚和水汽过量氖值白天大于夜晚，综合说明白天局地蒸发较夜晚强烈;夏季受西风水汽影响显著。其中，6月主要受西风水汽和北冰洋水汽影响，大8月主要受西风水汽和东南方向水汽影响，且8月受东南方向水汽影响最为明显;水汽运移路径上下垫面地形和气压带移动会影响水汽后向轨迹高度，西北方向上水汽输送通道较顺畅，风速较大，有利于水汽的输送;水汽蒸发源地主要集中在研究区周围及以东、以北部，其次是西北部。绿洲是主要的水汽蒸发源地，其次是城市和河流，白天较夜晚局地蒸发强烈且面积大。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-10 Cooperative journals: 《干旱区研究》
Abstract：基于中国地面气象站逐小时观测资料、GDAS气象数据及2016—2017年NCEP/NCAR再分析资料，利用拉格朗日后向轨迹模型，结合比湿变化对新疆短时强降水的水汽来源进行订正。结果表明：① 新疆的水汽主要来源于包括里海、黑海、地中海、大西洋、北冰洋和附近的内陆地区；新疆常年受西风影响，偏南西风影响较大；② 阿尔泰-塔城森林草原自然区和准噶尔盆地荒漠自然区水汽路径总体偏北，伊犁-巴音布鲁克（中天山）自然区和哈密-吐鲁番荒漠自然区受陆地水汽源的影响更大，而塔里木盆地极端干旱荒漠自然区水汽路径总体偏南。聚类分析结果显示，阿尔泰-塔城森林草原自然区的水汽来自于欧洲，准噶尔盆地荒漠自然区的水汽主要来自于中亚、里海和蒙古高原，塔里木盆地极端干旱荒漠自然区水汽主要来自塔里木盆地、西亚、中亚和黑海；③ 经过比湿判断水汽补给情况后，气团回溯路径普遍变短，水汽主要来自中亚、黑海、里海和附近的陆地；从主要水汽源地的传输水汽平均需要3.5 d左右，季节上表现为夏季的水汽源地最近，秋季的水汽源地较远，区域上阿尔泰-塔城森林草原自然区水汽源地最远，哈密-吐鲁番荒漠自然区水汽源地最近；④ 新疆各起始高度上的降水主要受偏北和偏南的西向气流影响，且从对水汽的贡献来看，偏北的西向气流大于偏南的。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-09 Cooperative journals: 《干旱区研究》
Abstract： 局地水汽再循环是陆地水循环过程的重要环节。在我国西北干旱区水汽再循环的绝对量虽然有限，但对区域降水的贡献（即水汽再循环率）却不容忽视。本文基于嵌套同位素模块的LMDZ模式模拟数据，运用同位素混合模型，对西北干旱区1979—2007年水汽再循环率的时空特征及其作用机制进行了分析。结果表明：研究时段内，外来水汽对降水的月尺度和年尺度贡献率都明显高于再循环水汽，季节上呈夏高冬低，年际上呈逐渐上升的态势；而再循环水汽的贡献率较低，呈夏季低冬季高且逐年下降（冬半年植物蒸腾水汽的贡献率在年际上呈上升趋势）的特点。外来水汽对降水的贡献率存在空间差异，山区附近的值往往较高，荒漠平原区的值则较低。就地表蒸发与植物蒸腾而言，地表蒸发对降水的贡献率整体低于植物蒸腾，但在小范围地区也有相反的规律。外来水汽和地表蒸发水汽的贡献量与其贡献率的空间分布特征基本一致，而植物蒸腾水汽在山区的贡献量高于荒漠平原区。
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