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A total of 12 indices of temperature extremes and 11 indices of precipitation ex-tremes at 111 stations in southwestern China at altitudes of 285-4700 m were examined for the period 1961-2008. Significant correlations of temperature extremes and elevation in-cluded the trends of diurnal temperature range, frost days, ice days, cold night frequency and cold day frequency. Regional trends of growing season length, warm night frequency, coldest night and warmest night displayed a statistically significant positive correlation with altitude. These characteristics indicated the obvious warming with altitude. For precipitation extreme indices, only the trends of consecutive dry days, consecutive wet days, wet day precipitation and the number of heavy precipitation days had significant correlations with increasing alti-tude owing to the complex influence of atmospheric circulation. It also indicated the increased precipitation mainly at higher altitude areas, whereas the increase of extreme precipitation events mainly at lowers altitude. In addition, the clearly local influences are also crucial on climate extremes. The analysis revealed an enhanced sensitivity of climate extremes to ele-vation in southwestern China in the context of recent warming. 相似文献
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Based on the meteorological data of 20 stations in the Hengduan Mountains region during 1961-2009, the annual and seasonal variation of potential evapotranspiration was analyzed in combination with the Penman-Monteith model. With the method of Spline interpolation under ArcGIS, the spatial distribution of potential evapotranspiration was presented to research the regional difference, and the correlation analysis was used to discuss the dominant factor affecting the potential evapotranspiration. The results indicated that the an-nual potential evapotranspiration showed a decreasing tendency since the 1960s, especially from the 1980s to 1990s, while it showed an increasing tendency since 2000. Regional potential evapotranspiration showed a rate of -0.17 mm a?1. Potential evapotranspiration in north, middle and south of the Hengduan Mountains exhibited decreasing trends over the studied period, and its regional trend was on the decline from southwest to northeast. 相似文献
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我国典型季风海洋性冰川区雪坑中主要阴、阳离子的来源 总被引：11，自引：0，他引：11
运用海盐示踪法、相关分析、趋势分析等方法,对我国两处典型季风海洋性冰川(海 螺沟1 号冰川和白水1 号冰川) 积累区雪坑主要化学离子来源进行了综合分析,结果表明： 两冰川区除Na+ 是海洋源外,其他离子主要是非海洋源;Cl-、NO3 -、SO4 2- 、K+、Ca2+、Mg2+ 非 海洋源所占的比重,在海螺沟1 号冰川依次为52%、99%、100%、98%、99.9%、83%,白水 1 号冰川依次为68%、99%、100%、98%、99%、59%;分析认为,海螺沟1 号冰川离子的非 海洋源主要是大气环流远源物质和高原面物质输入,而白水1 号冰川除上述来源外,冰川区 近源物质输入对离子浓度贡献很大。两冰川区各离子具体来源存在较大的差异性并且阴、阳 离子来源的共源性较低,其主要原因是：(1) 冰川区内局地环境的差异,比如岩性、山谷风系 统、地形地貌等;(2) 两冰川区离子淋溶作用强度的差异,分析认为,海螺沟1 号冰川离子淋 溶作用较强;(3) 不同离子的来源方式、沉降方式、自身化学特征以及沉积后过程不同所致。 相似文献
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1958-2005年祁连山老虎沟12号冰川变化特征研究 总被引：23，自引：8，他引：15
老虎沟12号冰川是祁连山最大的冰川, 面积为21.9 km2, 为极大陆型冷性复式山谷冰川. 该冰川监测开始于1958年, 1962年监测被迫终止;其后于20世纪70-80年代有过短期考察, 2005年恢复全面观测. 基于野外GPS观测, 两期1∶50 000地形图和两期1∶10 000地形图及Landsat ETM 遥感影像, 分析了过去近50 a来多时间段冰川的变化特征及其对气候变化的响应过程. 结果表明: 1957-1976年间冰川退缩约100 m, 平均退缩速率5 m·5a-1, 此后冰川归于平稳态; 1985-2005年间冰川退缩140.12 m, 退缩速率较之前(1957-1976年)提高了40.2%. 结合玉门镇气象资料分析认为, 升温幅度的增大是影响20世纪90年代中期以来老虎沟12号冰川退缩加剧的根本原因, 冰川在持续高温情景下的气候响应要敏感于低温情景. 相似文献
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干旱内陆河流域人居环境适宜性评价——以石羊河流域为例(英文) 总被引：6，自引：2，他引：4
The study employs slope,aspect,relief degree of land surface,land use,vegetation index,hydrology and climate,as evaluation indexes to set up the Human Settlements Environmental Index(HEI) model to evaluate the environmental suitability for human settlements in the Shiyang River Basin.By using GIS spatial analysis technology,such as spatial overlay analysis,buffer analysis and density analysis,the environmental suitability of the human settlement spatial situation and spatial pattern are established to analyze their spatial distribution.The results show that the index of suitability for human settlements in the Shiyang River Basin is between 17.13 and 84.32.In general,suitability for human settlements decreases from the southwest to the northeast.Seen from an area pattern,the suitable region is mainly distributed in the Minqin oasis,Wuwei oasis and Changning basin,which are about 1080.01 km 2 and account for 2.59% of the total area.Rather and comparatively suitable region is mainly distributed around the counties of Gulang,Yongchang and north of Tianzhu,which is about 1100.30 km 2.The common suitable region is mainly distributed outside the counties of Yongchang,Jinchuan and most parts of Minqin County,which are about 23328.04 km 2,accounting for 56.08% of the total area.The unsuitable region is mainly distributed upstream and to the north of the river,which is about 9937.60 km 2,accounting for 23.89% of the total area.Meanwhile,the least suitable region is distributed around the Qilian Mountains,which are covered by snow and cold desert and lie in the intersecting area between the Tengger Desert and Badain Jaran Desert.The total area is about 6154.05 km 2,accounting for 14.79% of the total area.Suitable regions for human habitation are mainly distributed around rivers in the form of ribbons and batches,while others are scattered.The distribution pattern is identical to the residential spatial pattern.In addition,the relationships between HEI and other factors have been analyzed.There is a clear logarithmic correlation between the residential environment and population,that is,the correlation coefficient between the evaluation value and population density reaches 0.851.There is also a positive correlation between the residential environment and economy,which reaches an evaluation value of 0.845 between the residential environment and GDP.Results also show that the environment is out of bearing with the existing population in Shiyang River Basin.Spatial distribution of population is profoundly affected by severe environmental problems,such as the expanded deserts,the hilly terrain and the changing climate.Surface water shortage and slow economic growth are bottlenecks for suitable human settlement in the Shiyang River Basin.Combining these problems with planning for construction of new country and the exploitation of local land,some residential areas should be relocated to improve the residential environment. 相似文献
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RS、GIS支持下高寒草原退化过程中土壤流失及治理模式仿真研究 总被引：1，自引：0，他引：1
利用GIS的栅格数据空间分析功能,将研究空间离散化为25 m×25 m的栅格;在对土壤流失方程RUSLE进行实例化的基础上根据各算法生成各因子栅格图,借助GIS地图代数运算,实现了该区的土壤流失估算.研究区2002年土壤流失轻度以上面积为1 203.574 3 hm2,占研究区总流失面积的18.02%.总土壤流失总量为91 397.506 t/a,年平均流失模数为l 369.070 5 t·km-2·a-1,按照流失等级划分标准,属于轻度流失.对该区三种治理模式-加速治理型、传统经营型和稳步发展型进行仿真研究,结果表明:土壤侵蚀过程与土地利用和治理强度密切相关,轻度与中度侵蚀面积有明显的滞后增加趋势,加速治理型模式是促进该区农牧业发展和水土保持良性循环的最佳模式.在RS、GIS支持下可以掌握土壤流失面积和流失量,为高寒草原退化过程中土壤流失模拟控制研究提供了方法和科学依据. 相似文献
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典型冰冻圈地区植被变化对人类活动的响应研究
——以祁连山为例 总被引：1，自引：1，他引：0
在全球气候变化、种植业结构调整等背景下,亟需对祁连山区的植被展开长期有效的监测和持续研究。基于2000-2017年分辨率为250 m的MODIS数据,采用Mann-Kendall时间序列非参数估计模型、相关分析等方法,分析了祁连山区生长季NDVI与植被盖度的时空变化特征及其与气候因子的相关性,并从正反两方面就人类活动对对植被的影响做了讨论,得出结论如下：（1）从东向西祁连山年平均NDVI整体上逐渐减小,NDVI随海拔升高呈先增大后减小的特征,NDVI最大的区域分布在海拔2 700~2 900 m的范围内;（2）祁连山区域内NDVI显著减小的区域占祁连山总面积的0.6%,而显著增加的区域占总面积的33.6%,植被呈现出整体向好,局部退化的趋势;（3）2000-2017年,林地、草地和其他土地利用区的植被盖度分别以0.0029、0.0026和0.0004的速率增加,工矿用地的覆盖度以0.0112的速率在减少,反映出工矿业开发活动是造成植被盖度下降的主要因子;（4）植树造林区植被NDVI以0.0455的速度增加,而工程实施和矿产开发区NDVI以0.0125速度降低,表明人类活动是导致植被群落变化的主要因素之一。 相似文献
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1960-2009年横断山区潜在蒸发量时空变化 总被引：8，自引：2，他引：6
以横断山区20 个气象站1960-2009 年逐日气象数据为基础,应用1998 年FAO 修正的Penman-Monteith 模型分析了横断山区潜在蒸发量的变化,在ArcGIS 环境下通过样条插值法分析了潜在蒸发量变化的时空分异,并对影响潜在蒸发量变化的气象因素进行了讨论,结果表明：年潜在蒸发量自20 世纪60 年代中期以来呈波动减小趋势,20 世纪80 年代中期之后减小趋势更加明显,2000-2009 年呈增加趋势。潜在蒸发量的年际变化倾向率为-0.17 mm a-1,从空间分布来看,北部、中部、南部都呈减少趋势,倾向率由北向南逐渐减小。从季节来看,秋季和冬季潜在蒸发量呈增加趋势,春季和夏季呈减小趋势,春季减小趋势大于夏季,秋季增加趋势大于冬季。气温上升、风速和日照时数的降低是横断山区潜在蒸发量减少的主导因素,风速和日照时数的下降导致春季和夏季潜在蒸发量减小,气温上升导致秋季和冬季潜在蒸发量增加。 相似文献
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利用SEBAL和改进的SEBAL模型估算黑河中游戈壁、绿洲的蒸散发 总被引：1，自引：0，他引：1
蒸散发是干旱、半干旱地区内陆河流域水分消耗的主要途径, 利用遥感估算流域尺度上的蒸散发对内陆河流域水循环和水资源的合理利用具有重要的指导意义. 基于2012年开展的黑河流域生态-水文过程综合遥感观测联合试验(HiWATER)的观测资料和高分辨率的ASTER影像, 分别利用 SEBAL 模型和改进的SEBAL(M-SEBAL)模型估算黑河中游不同时期戈壁、绿洲等不同下垫面的蒸散发, 通过涡动观测数据对比分析了SEBAL模型和M-SEBAL模型估算戈壁、绿洲蒸散发的精度. 结果表明: SEBAL模型在绿洲低估感热通量, 高估潜热通量; 在戈壁高估感热通量, 低估潜热通量. M-SEBAL 模型充分考虑不同下垫面地表辐射温度与植被覆盖度之间的关系, 能很好地反映不同植被覆盖区域的湍流通量的异质性, 估算黑河中游戈壁、绿洲蒸散发的精度高于SEBAL模型. 相似文献