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1. chinaXiv:202112.00056 [pdf]

乌兹别克斯坦灌溉农业发展及其对生态环境和经济发展的影响

李琦
Subjects: Geosciences >> Geography

乌兹别克斯坦作为中亚干旱区重要的农业大国,由于其独有的气候条件,灌溉是决定其农 业生产的主要控制因素,因此,研究其灌溉农业发展历程对于保障农业生产与自然环境安全具有 重要意义。通过查阅乌兹别克斯坦灌溉农业发展领域的相关文献,结合联合国粮食及农业组织、 联合国数据检索系统等官方网站提供的资料数据,总结灌溉农田面积、人口、主要作物产量及农业 产值等数据的变化规律,阐述了乌兹别克斯坦灌溉农业的发展历程,分析讨论由农业灌溉引起的一系列环境问题及其对社会经济的影响。结果表明:(1)由于气候干旱少雨,乌兹别克斯坦灌溉用水主要来自阿姆河及锡尔河,下游河道径流量及咸海蓄水量持续下降,暴露河床内大量松散沉积 物并导致频繁的沙尘天气。(2)乌兹别克斯坦整体农业灌溉技术较为落后,过度引水使得部分地表径流汇聚在灌区低洼地带,抬升地下水位,最终引发严重的区域土壤盐渍化,故全面推广先进灌排 技术,是该国未来灌溉农业与生态环境健康发展的主要方向。(3)农业生产是乌兹别克斯坦重要的经济来源,对国内生产总值有显著的正向影响。此研究可为干旱区农业发展及水资源管理提供借鉴。

submitted time 2021-12-14 From cooperative journals:《干旱区地理》 Hits2815Downloads141 Comment 0

2. chinaXiv:202112.00066 [pdf]

基于时频分析的 LSTM 组合模型径流预测

蔡文静
Subjects: Geosciences >> Geography

针对变化环境下径流时间序列复杂的非线性、非平稳性特征,为提高中长期径流预测的准 确性,运用多种时频分析方法构建组合预报模型以探究适用性。以干旱区典型内陆河玛纳斯河为例,利用经验模态分解(EMD)、变分模态分解(VMD)、离散小波变换(DWT)时频分析方法对径流时间序列进行多尺度分解,得到不同频率和特征的子序列。以前期径流、降水量、气温、大气环流因 子等作为长短期记忆神经网络模型(LSTM)的输入变量,采用随机森林法和 Pearson 相关系数法确 定各子序列的最佳预报因子,基于时频分析方法分别构建 EMD-LSTM、VMD-LSTM、DWT-LSTM 组 合预报模型,通过 LSTM 模型对各子序列进行预测,加和重构获得最终预测结果,并与单一的误差 反向传播神经网络(BP)、极限学习(ELM)、LSTM 模型的预测结果进行对比分析。结果表明:组 合模型 VMD-LSTM 预报误差最小、精度最高,纳什系数保持在 0.9 以上,有效避免了过拟合等问题, 其径流极值预测误差在 15%以内,对径流总体趋势预测和极值的追踪均有良好效果。研究结果可为流域水资源规划与调度提供参考。

submitted time 2021-12-14 From cooperative journals:《干旱区地理》 Hits2727Downloads87 Comment 0

3. chinaXiv:202112.00109 [pdf]

新疆和田河径流丰枯评价及组合分析

黄星
Subjects: Geosciences >> Geography

基于同古孜洛克和乌鲁瓦提水文站1960—2016年年尺度与月尺度径流数据,分别采用均值标准差法和模糊集对分析法对和田河2大支流进行丰枯类别评价,并在此基础上优选模糊集对法和Copula函数法计算2条源流径流丰枯组合概率,同时分析2支流间互补的优劣性。结果表明:模糊集对法考虑了年内径流贡献度使评价结果更客观,玉龙喀什河枯水年占比最高,应提高枯水期水资源利用,喀拉喀什河平水年占比最高,表明喀拉喀什河常年来水稳定;统计法和Copula函数得出的丰枯概率存在差异性与数据使用、划分方式及源流区域海拔有关,2种方法结果均表现为异步丰枯概率大于同步丰枯概率,两支流具有较好互补性。该结果能更清晰的描述和田河径流丰枯状态及丰枯组合特性,可为和田河流域水资源调度提供参考和决策依据。

submitted time 2021-12-12 From cooperative journals:《干旱区研究》 Hits71Downloads30 Comment 0

4. chinaXiv:202110.00038 [pdf]

气候与下垫面变化对叶尔羌河源流径流的影响

任才
Subjects: Geosciences >> Atmospheric Sciences

以叶尔羌河流域上游河源区为研究区,构建嵌入了冰川模块的 SWAT 分布式水文模型,对 卡群水文站 1968—2017 年逐月径流进行模拟,评价该模型在研究区内的适用性,基于模拟结果分 析研究区冰川径流年际变化与年内分布情况,并定量核算气候和下垫面变化对径流变化的贡献 率。结果表明:该模型在研究区径流模拟中具有良好的适用性,校准期(1968—1992 年)与验证期(1993—2017 年)的决定系数(R2)分别为 0.77 和 0.86,纳什系数(NSE)分别为 0.76 和 0.85,均方根误 差与实测值标准差的比值(RSR)分别为 0.49 和 0.38,偏差百分比(PBIAS)分别为-7.4%和 0.6%。经 模拟,研究区近 50 a 冰川径流量总体呈增加趋势,且其占总径流量的比重约为 51.1%;年内冰川产 流主要发生在 6—9 月,占全年冰川径流量的 90.0%以上。气候和下垫面变化分别使月径流量增加 6.62 m3·s-1 和 0.41 m3·s-1,其中气候变化的贡献率为 94.2%,即气候变化对研究区径流的影响占主导 地位。研究成果可为理解研究区的历史径流变化成因及预测未来径流的演变趋势提供科学依据。

submitted time 2021-10-10 From cooperative journals:《干旱区地理》 Hits2750Downloads146 Comment 0

5. chinaXiv:202108.00009 [pdf]

Promoting the production of salinized cotton field by optimizing water and nitrogen use efficiency under drip irrigation

LIN En; LIU Hongguang; LI Xinxin; LI Ling; Sumera ANWAR
Subjects: Geosciences >> Geography

Cotton is the main economically important crop in Xinjiang, China, but soil salinization and shortage of water and nutrients have restricted its production. A field experiment was carried out in the salinity-affected arid area of Northwest China from 2018 to 2019 to explore the effects of nitrogen and water regulation on physiological growth, yield, water and nitrogen use efficiencies, and economic benefit of cotton. The salinity levels were 7.7 (SL) and 12.5 dS/m (SM). Drip irrigation was used with low, medium and adequate irrigation levels representing 60%, 80% and 100% of cotton crop water demand, respectively, and three nitrogen applications, i.e., 206, 275 and 343 kg/hm2, accounting for 75%, 100% and 125% of local N application, respectively were used. The multi-objective optimization based on spatial analysis showed that, at SL salinity, water use efficiency (WUE), nitrogen use efficiency (NUE), economic benefit and yield simultaneously reached more than 85% of their maxima at 379.18–398.32 mm irrigation and 256.69–308.87 kg/hm2. At SM salinity, WUE, yield and economic benefit simultaneously reached more than 85% of their maxima when irrigation was 351.24–376.30 mm and nitrogen application was 230.18–289.89 kg/hm2. NUE, yield and economic benefit simultaneously reached their maxima at 428.01–337.72 mm irrigation, and nitrogen application range was 222.14–293.93 kg/hm2. The plants at SL salinity had 21.58%–46.59% higher WUE rates, 14.91%–34.35% higher NUE rates and 20.71%–35.34% higher yields than those at SM salinity. The results are of great importance for the nutrient and water management in cotton field in the arid saline area.

submitted time 2021-08-06 From cooperative journals:《Journal of Arid Land》 Hits1728Downloads220 Comment 0

6. chinaXiv:202108.00020 [pdf]

咸水灌溉条件下塔里木河下游沙漠土壤水盐运移数值模拟

王世明; 范敬龙
Subjects: Geosciences >> Geochemistry

在塔里木河下游沙漠地区防护林建设过程中,地下咸水灌溉条件下土壤剖面水盐变化明 显,且存在一定的规律性。为掌握土壤垂向水盐动态,建立数值模型是十分高效的手段,通过重建 土壤剖面的水盐动态过程,可揭示高盐环境下土壤水盐运移规律,服务防护林生态工程建设和后续可持续灌溉管理。通过 HYDRUS-1D 模拟防护林建设初期不同矿化度地下水灌溉条件下土壤水盐分布特征和时间变化,并根据实测的土壤水盐数据,优化土壤水分特征参数,评价模型的适用 性。结果表明:表层(0~30 cm)土壤含水量和含盐量受灌溉影响大,数值波动剧烈,且土壤盐分表 聚强烈;深层(50~150 cm)则受灌溉的影响小,数值波动小。数值模型模拟值与实测值吻合,能较好地反映土壤水盐运移情况,建立的模型可用于模拟不同矿化度灌溉条件下塔里木河下游流动沙漠地区土壤水盐运移状况,为该地区生态防护林建设提供理论基础和技术支撑。

submitted time 2021-08-02 From cooperative journals:《干旱区地理》 Hits674Downloads235 Comment 0

7. chinaXiv:202107.00023 [pdf]

Impacts of climate change and human activities on water resources in the Ebinur Lake Basin, Northwest China

WANG Yuejian; GU Xinchen; YANG Guang; YAO Junqiang; LIAO Na
Subjects: Geosciences >> Geography

Changing climatic conditions and extensive human activities have influenced the global water cycle. In recent years, significant changes in climate and land use have degraded the watershed ecosystem of the Ebinur Lake Basin in Xinjiang, Northwest China. In this paper, variations of runoff, temperature, precipitation, reference evapotranspiration, lake area, socio-economic water usage, groundwater level and water quality in the Ebinur Lake Basin from 1961 to 2015 were systematically analyzed by the Mann-Kendall test methods (M-K) mutation test, the cumulative levelling method, the climate-sensitive method and land-use change index. In addition, we evaluated the effects of human activities on land use change and water quality. The results reveal that there was a significant increase in temperature and precipitation from 1961 to 2015, despite a decrease in reference evapotranspiration. The Wenquan station was not significantly affected by human activities as it is situated at a higher altitude. Runoff at this station increased significantly with climate warming. In contrast, runoff at the Jinghe station was severely affected by numerous human activities. Runoff decreased without obvious fluctuations. The contributions of climate change to runoff variation at the Jinghe and Wenquan stations were 46.87% and 58.94%, respectively; and the contributions of human activities were 53.13% and 41.06%, respectively. Land-use patterns in the basin have changed significantly between 1990 and 2015: urban and rural constructed lands, saline-alkali land, bare land, cultivated land, and forest land have expanded, while areas under grassland, lake, ice/snow and river/channel have declined. Human activities have dramatically intensified land degradation and desertification. From 1961 to 2015, both the inflow into the Ebinur Lake and the area of the lake have declined year by year; groundwater levels have dropped significantly, and the water quality has deteriorated during the study period. In the oasis irrigation area below the runoff pass, human activities mainly influenced the utilization mode and quantity of water resources. Changes in the hydrology and quantity of water resources were driven primarily by the continuous expansion of cultivated land and oasis, as well as the growth of population and the construction of hydraulic engineering projects. After 2015, the effects of some ecological protection projects were observed. However, there was no obvious sign of ecological improvement in the basin, and some environmental problems continue to persist. On this basis, this study recommends that the expansion of oasis should be limited according to the carrying capacity of the local water bodies. Moreover, in order to ensure the ecological security of the basin, it is necessary to determine the optimal oasis area for sustainable development and improve the efficiency of water resources exploitation and utilization.

submitted time 2021-07-23 From cooperative journals:《Journal of Arid Land》 Hits714Downloads270 Comment 0

8. chinaXiv:202104.00042 [pdf]

1961—2017年北疆初终霜日及霜期时空变化特征

张鑫; 楼俊伟
Subjects: Geosciences >> Atmospheric Sciences

利用 1961—2017 年北疆 37 个地面气象站逐日最低气温观测资料,结合常规气象统计方 法,分析北疆地区初、终霜日和霜期的时空演变特征。结果表明:(1)北疆平均初霜日以 2.2 d·(10a)-1 速率推迟;平均终霜日以 1.7 d·(10a)-1 速率提前;平均霜期以 3.9 d·(10a)-1 速率缩短;初、终 霜日和霜期的主周期均为 2 a 左右。(2)北疆霜期缩短趋势较大(小)的地区,能较好的对应其初霜 日推迟、终霜日提前较强(弱),伊犁州、塔城地区北部及东天山东北部霜期的缩短趋势最为显著, 博州至天山北坡一线居中,阿勒泰地区霜期的缩短趋势最弱。(3)北疆大部分地区初霜日的变 化趋势与海拔高度有很好的相关性,其初霜日的推迟速度随海拔高度的增加而减小,垂直递减率 为-0.077 d·(a·km)-1;秋季气候变暖是初霜日推迟的主要原因,春、秋季气候变暖同时影响霜期缩 短,且秋季的影响更大。

submitted time 2021-04-13 From cooperative journals:《干旱区地理》 Hits690Downloads492 Comment 0

9. chinaXiv:202103.00075 [pdf]

补水与制冷不同初始条件对黏土冻融过程 影响的试验研究

孙雯; 宋玲; 陈新瑞; 许清峰; 陈鹏; 杨禹锟; 吴浩
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology

为研究补水过程中新疆黏土的冻融特征,于室内开展单向冻融模型试验,分析非饱和黏土单向冻融过程中温度、冻胀量、融沉量的时空变化规律。结果表明:冻融量随温度的变化而变化;冻融初期,温度变化较快,冻胀/融沉量开始产生并逐渐增大;冻融后期,温度变化减慢并趋于稳定。两种条件下融化时长均短于冻结时长,初始含水率越大的土样,冻融历时、冻结/融化深度及冻胀/融沉量越大。研究结果表明:初始含水率的不同会导致水冰之间的相变差异及土体水热的变化,从而造成冻融过程中温度场和冻融量不同。此研究所得出的冻融温度场、冻结/融化锋面和冻胀/融沉量的变化规律,可为寒旱区水利工程的设计、修建及运营维护提供理论参考。

submitted time 2021-01-26 From cooperative journals:《干旱区研究》 Hits544Downloads377 Comment 0

10. chinaXiv:202103.00098 [pdf]

天山典型冰川区径流年内变化分析

刘爽爽; 李忠勤; 张慧; 金爽; 邓海军; 王璞玉; 贾玉峰
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology

基于天山乌鲁木齐河源1号冰川区1980—2016年的水文和气象资料,对冰川区径流在月、日和时尺度的变化特征及其原因进行了分析。结果表明:(1)1980—2016年该区消融期(5—9月)径流总体呈上升趋势,倾向率为3.44×104 m3·a-1,其中6—8月上升趋势较为显著;37 a来8月对径流增多贡献率最大,其次为6月和7月,5月和9月最低;消融期径流在1993年显著增加,5—8月径流均在20世纪90年代发生突变。(2)日径流量自1980s、1990s至2000s显著增加,而2010—2016年径流量有所减少;日径流峰值出现时间在1980s—1990s有明显提前趋势,但在2010—2016年,日径流峰值出现日期趋于稳定。(3)2011—2016年7月和8月昼夜流量变化较为显著;日流量曲线呈现“峰-谷”的日变化特征,且7月和8月峰值出现时间小于6月和9月。(4)1980—2016年,该流域消融期气温和降水均呈上升趋势;相关分析表明6—8月径流与气温均呈显著正相关。总体上冰川区年内径流与气温、降水在月、日尺度上表现出较好的同步性,表明其变化主要受控于同期的气温与降水量状况。

submitted time 2021-01-25 From cooperative journals:《干旱区研究》 Hits721Downloads497 Comment 0

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