分类： 地球科学 >> 水文学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： The wide valley of the Yarlung Zangbo River is one of the most intense areas in terms of aeolian activity on the Tibetan Plateau, China. In the past, the evaluation of the intensity of aeolian activity in the QuxuSangri section of the Yarlung Zangbo River Valley was mainly based on data from the old meteorological stations, especially in non-sandy areas. In 2020, six new meteorological stations, which are closest to the new meteorological stations, were built in the wind erosion source regions (i.e., sandy areas) in the QuxuSangri section. In this study, based on mathematical statistics and empirical orthogonal function (EOF) decomposition analysis, we compared the difference of the wind regime between new meteorological stations and old meteorological stations from December 2020 to November 2021, and discussed the reasons for the discrepancy. The results showed that sandy and non-sandy areas differed significantly regarding the mean velocity (8.3 (0.3) versus 7.7 (0.3) m/s, respectively), frequency (12.9% (6.2%) versus 2.9% (1.9%), respectively), and dominant direction (nearly east or west versus nearly north or south, respectively) of sand-driving winds, drift potential (168.1 (77.3) versus 24.0 (17.9) VU (where VU is the vector unit), respectively), resultant drift potential (92.3 (78.5) versus 8.7 (9.2) VU, respectively), and resultant drift direction (nearly westward or eastward versus nearly southward or northward, respectively). This indicated an obvious spatial variation in the wind regime between sandy and non-sandy areas and suggested that there exist problems when using wind velocity data from non-sandy areas to evaluate the wind regime in sandy areas. The wind regime between sandy and non-sandy areas differed due to the differences in topography, heat flows, and their coupling with underlying surface, thereby affecting the local atmospheric circulation. Affected by large-scale circulations (westerly jet and Indian monsoon systems), both sandy and non-sandy areas showed similar seasonal variations in their respective wind regime. These findings provide a credible reference for re-understanding the wind regime and scientific wind-sand control in the middle reaches of the Yarlung Zangbo River Valley.
分类： 地球科学 >> 地理学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Pendjari Biosphere Reserve (PBR), a primary component of the W-Arly-Pendjari transboundary biosphere reserve, represents the largest intact wild ecosystem and pristine biodiversity spot in West Africa. This savannah ecosystem has long been affected by fire, which is the main ecological driver for the annual rhythm of life in the reserve. Understanding the fire distribution patterns will help to improve its management plan in the region. This study explores the fire regime in the PRB during 20012021 in terms of burned area, seasonality, fire frequency, and mean fire return interval (MFRI) by analysing moderate resolution imaging spectroradiometer (MODIS) burned area product. Results indicated that the fire season in the PBR extends from October to May with a peak in early dry season (NovemberDecember). The last two fire seasons (20192020 and 20202021) recorded the highest areas burned in the PBR out of the twenty fire seasons studied. During the twenty years period, 8.2% of the reserve burned every 1011 months and 11.5% burned annually. The largest part of the reserve burned every one to two years (63.1%), while 8.3% burned every two to four years, 5.8% burned every four to ten years, and 1.9% burned every ten to twenty years. Only 1.3% of the entire area did not fire during the whole study period. Fire returned to a particular site every 1.39 a and the annual percentage of area burned in the PBR was 71.9%. The MFRI (MFRI
分类： 地球科学 >> 地理学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Science and policy have been interlinked for decades and perform essential nexus conditions in the governing aspects of environmental scenarios. This review paper examines the present challenges in the sciencepolicy interface in terms of water governance in the Caspian Sea and identifies effective conditions that may be used in the current context to enhance the mechanism. The evaluation of the sciencepolicy link in the water policy of the Caspian Sea reveals a gap between knowledge producer and governance system, impeding the translation of scientific information into action. Complicated and context-dependent solutions make it challenging to establish effective sciencepolicy processes in the Caspian Sea water governance settings. Establishing a common governing authority, implementing water and resource management regulations, and protecting the natural environment through legal frameworks are crucial steps to address these concerns and ensure sustainable development. Collaboration among coastal states is essential in environmental, economic, and social aspects of regional development. However, the lack of a comprehensive approach, coherent activities, and effective utilization of national and regional power has hindered efforts to halt the environmental degradation of the Caspian Sea. Local governments need to recognize their responsibility to protect and utilize the Caspian Sea for present and future generations, considering both environmental and human security. The interlinkage of the Caspian Sea water governance with the Organization for Economic Co-operation and Development (OECD) water governance principles offers a framework for policymakers to assess gaps and make necessary amendments to existing mechanisms. Effective sciencepolicy interaction, engagement of diverse stakeholders, institutionalizing agreements, and addressing collective action issues are critical for successful water governance.
分类： 地球科学 >> 地理学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Analysis of environmental significance and hydrochemical characteristics of river water in mountainous regions is vital for ensuring water security. In this study, we collected a total of 164 water samples in the western region of the Altay Mountains, China, in 2021. We used principal component analysis and enrichment factor analysis to examine the chemical properties and spatiotemporal variations of major ions (including F, Cl, NO3, SO42, Li+, Na+, NH4+, K+, Mg2+, and Ca2+) present in river water, as well as to identify the factors influencing these variations. Additionally, we assessed the suitability of river water for drinking and irrigation purposes based on the total dissolved solids, soluble sodium percentage, sodium adsorption ratio, and total hardness. Results revealed that river water had an alkaline aquatic environment with a mean pH value of 8.00. The mean ion concentration was ranked as follows: Ca2+>SO42>Na+>NO3>Mg2+>K+>Cl>F>NH4+>Li+. Ca2+, SO42, Na+, and NO3 occupied 83% of the total ion concentration. In addition, compared with other seasons, the spatial variation of the ion concentration in spring was obvious. An analysis of the sources of major ions revealed that these ions originated mainly from carbonate dissolution and silicate weathering. The recharge impact of precipitation and snowmelt merely influenced the concentration of Cl, NO3, SO42, Ca2+, and Na+. Overall, river water was in pristine condition in terms of quality and was suitable for both irrigation and drinking. This study provides a scientific basis for sustainable management of water quality in rivers of the Altay Mountains.
分类： 地球科学 >> 地理学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Groundwater overexploitation is a serious problem in the Turpan Basin, Xinjiang Uygur Autonomous Region of China, causing groundwater level declines and ecological and environmental problems such as the desiccation of karez wells and the shrinkage of lakes. Based on historical groundwater data and field survey data from 1959 to 2021, we comprehensively studied the evolution of groundwater recharge and discharge terms in the Turpan Basin using the groundwater equilibrium method, mathematical statistics, and GIS spatial analysis. The reasons for groundwater overexploitation were also discussed. The results indicated that groundwater recharge increased from 14.58108 m3 in 1959 to 15.69108 m3 in 1980, then continued to decrease to 6.77108 m3 in 2021. Groundwater discharge increased from 14.49108 m3 in 1959 to 16.02108 m3 in 1989, while continued to decrease to 9.97108 m3 in 2021. Since 1980, groundwater recharge-discharge balance has been broken, the decrease rate of groundwater recharge exceeded that of groundwater discharge and groundwater recharge was always lower than groundwater discharge, showing in a negative equilibrium, which caused the continuous decrease in groundwater level in the Turpan Basin. From 1980 to 2002, groundwater overexploitation increased rapidly, peaking from 2003 to 2011 with an average overexploitation rate of 4.79108 m3/a; then, it slowed slightly from 2012 to 2021, and the cumulative groundwater overexploitation was 99.21108 m3 during 19802021. This research can provide a scientific foundation for the restoration and sustainable use of groundwater in the overexploited areas of the Turpan Basin.
分类： 地球科学 >> 地理学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Climate change caused by past, current, and future greenhouse gas emissions has become a major concern for scientists in the field in many countries and regions of the world. This study modelled future precipitation change by downscaling a set of large-scale climate predictor variables (predictors) from the second generation Canadian Earth System Model (CanESM2) under two Representative Concentration Pathway (RCP) emission scenarios (RCP4.5 and RCP8.5) in the semi-arid Borana lowland, southern Ethiopia. The Statistical DownScaling Model (SDSM) 4.2.9 was employed to downscale and project future precipitation change in the middle (20362065; 2050s) and far (20662095; 2080s) future at the local scale. Historical precipitation observations from eight meteorological stations stretching from 1981 to 1995 and 1996 to 2005 were used for the model calibration and validation, respectively, and the time period of 19812018 was considered and used as the baseline period to analyze future precipitation change. The results revealed that the surface-specific humidity and the geopotential height at 500 hPa were the preferred large-scale predictors. Compared to the middle future (2050s), precipitation showed a much greater increase in the far future (2080s) under both RCP4.5 and RCP8.5 scenarios at all meteorological stations (except Teletele and Dillo stations). At Teltele station, the projected annual precipitation will decrease by 26.53% (2050s) and 39.45% (2080s) under RCP4.5 scenario, and 34.99% (2050s) and 60.62% (2080s) under RCP8.5 scenario. Seasonally, the main rainy period would shift from spring (March to May) to autumn (September to November) at Dehas, Dire, Moyale, and Teltele stations, but for Arero and Yabelo stations, spring would consistently receive more precipitation than autumn. It can be concluded that future precipitation in the semi-arid Borana lowland is predicted to differ under the two climate scenarios (RCP4.5 and RCP8.5), showing an increasing trend at most meteorological stations. This information could be helpful for policymakers to design adaptation plans in water resources management, and we suggest that the government should give more attention to improve early warning systems in drought-prone areas by providing dependable climate forecast information as early as possible.
点击量
点击量
下载量
评论
