青藏高原湖泊变化遥感监测及其对气候变化的响应研究进展

青藏高原位于中国西南部、亚洲中部,平均海拔高程大于4000 m,面积约300万km²,是“世界屋脊”,与周边地区一起常被称为地球的“第三极”。青藏高原分布着约1200个面积大于1 km²的湖泊,占中国湖泊数量与面积的一半;同时也是黄河、长江、恒河、印度河等大河的源头,被称为“亚洲水塔”。近几十年来,在全球变暖的背景下,青藏高原升温更加突出,其能量与水循环发生了显著变化,气候趋于暖湿化,冰川加速消融,湖面水位上升。湖泊是气候变化的重要指标,青藏高原湖泊分布密集、人为活动影响较小,多源遥感数据的广泛应用,为监测高原湖泊变化提供了难得的契机。本文依托国家自然科学基金青年项目“基于多源遥感的青藏高原内流区湖泊水量变化及水体相态转换研究(2000-2009年)”,主要研究进展为：初步查明了西藏高原的湖泊数量、面积及水位变化与时空格局,以及湖泊水量变化与水量平衡;探讨了湖泊变化对气候变化的响应。目前对青藏高原湖泊的变化及驱动因素虽有一些认识,但其定量的水量平衡及驱动机制还有待于进一步研究。这对了解世界第三极、一带一路国家和地区水资源状况与变化、生态文明和生态安全屏障建设具有重要的意义,同时也可为第三极国家公园的建立提供重要的科学基础。     

近百年来中国冰川变化及其对气候变化的敏感性研究进展

冰川变化是气候变化的产物,也是气候变化的指示器.在全球变暖的背景下,近百年来我国冰川消融强烈,以退缩为主.本文对近百年来我国冰川末端退缩、物质平衡变化和冰川面积变化方面的研究成果进行了综合分析.从时间和空间两方面探讨了我国冰川变化对气候变化响应的敏感性.结果表明,我国冰川末端变化对气候变化的响应在时间上要滞后10～20年,冰川末端退缩、物质平衡变化和面积变化的幅度在青藏高原边缘和周边地区要大于高原内部,对气候变化响应的敏感性也由内部向边缘增强.最后指出了我国冰川变化研究中存在的主要问题及今后发展趋势.     

基于流量监测的西藏东南部然乌湖水量平衡季节变化及其补给过程分析

青藏高原分布着亚洲大陆最大的湖泊群,其湖泊变化对气候变化响应敏感。基于遥感数据的湖泊面积变化不足以反映外流湖对气候变化的响应,需借助湖泊水量平衡过程分析来进一步研究各补给要素的变化。本文利用2015年4月-11月然乌湖水文气象监测数据,通过建立流量—水位关系,依据连续的水位数据重建了观测期内然乌湖主要径流的水文过程线,并结合SRM模型分析了然乌湖的水量平衡过程及季节变化。结果表明,观测期内然乌湖入湖水量约为18.49×10⁸ m³,其中冰川融水约为10.06×10⁸ m³,冰川融水占然乌湖补给的54%以上,湖面降水、湖面蒸发对湖泊水量平衡过程影响微弱。流域降水对湖泊的补给具有明显的季节特征。春季受西风南支扰动影响,然乌湖地区降水量大,降水是春季然乌湖的主要补给源。夏季和早秋由于气温升高,冰川消融量大,冰川融水是湖泊补给的主控因素。在未来气候变暖的条件下,冰川融水将会在湖泊补给中占据更大比例,并可能使得流域内的冰湖水量增加,产生潜在灾害风险。     

近20年青海湖水量变化遥感分析

青藏高原湖泊水量的变化是揭示全球气候变化及其区域水循环响应的重要信息载体。区别于常用的水文学方法,本文利用MODIS遥感影像和LEGOS高度计多年连续数据,基于湖泊水位—面积关系,探讨了湖泊水量变化的遥感分析方法,并以青藏高原面积最大的青海湖为例,揭示青海湖近20年来(2001-2016)湖泊水量年内与年际变化特征。主要结论为：青海湖湖泊面积在2001-2016年间整体扩张了187.9 km²,变化速率为11.6 km²/a;水位在2001-2014年间上升了1.15 m,变化速率为0.10 m/a。青海湖水位—面积关系表现为二次函数关系(相关系数R²=0.83)。基于水位—面积关系,进一步估算分析了青海湖水量平衡的净收支及其年内和年际变化。近20年来,青海湖水量总体呈增加趋势,其变化率约为4.5\times {10}^8m³/a。降水的增加与蒸发能力的下降是湖泊水量增加决定性的驱动因子。     

全球变暖对青藏高原不同补给类型湖泊生产力的影响

研究以青藏高原阿翁错和托素湖湖泊沉积物为研究对象,通过多指标(总有机碳含量、有机碳同位素和有机碳埋藏速率等)综合分析,重建不同补给类型湖泊的生产力变化及碳循环过程。结果显示：全球变暖对不同类型湖泊的生产力的影响存在显著差异。在以降水和冰川融水为主要补给源的阿翁错,全球变暖造成冰川融水补给增加。当指示冰川融水补给量变化的δ¹⁸O_carb值逐渐偏负时,湖泊沉积物TOC含量逐渐升高;指示冰川融水输入造成湖泊面积持续扩张,营养物质增加,湖泊生产力提高;当湖泊面积扩张较快,即冰川融水在短时间内快速输入时,TOC含量下降,可能是由于当冰川融水输入过多,造成湖水温度下降过快时,底栖藻类生产力下降,进而湖泊固碳能力下降。对于受人类活动影响的托素湖,全球变暖对湖泊水文过程及生产力的影响较小,δ¹⁸O_carb值变化主要受控于农业灌溉活动引起的湖泊补给水量的变化。当δ¹⁸O_carb值升高时,TOC含量增加;推测是由于农业灌溉耗水量增加导致湖泊补给水量减少,湖泊水位下降,湖泊底部...     

1972-2012年青藏高原中南部内陆湖泊的水位变化

青藏高原的湖泊水位变化能够清晰的记录湖泊波动,分析近几十年来气候变暖背景下青藏高原典型湖泊水位的动态变化,对理解全球变化的区域响应特征和规律有重要意义。本文利用多源遥感数据,获取1972-2012年青藏高原南部地区5个典型湖泊的面积与水位序列,并分析了40年来湖泊水位的变化特征。研究结果表明,1972-2012年,普莫雍错,塔若错,扎日南木错水位呈上升趋势,分别上升了0.89 m、0.70 m、0.40 m;同期,佩枯错与玛旁雍错的水位呈下降趋势,分别下降了1.70 m、0.70 m。总体来看,五个湖泊在1990s-2012年的变化比1970s-1990s的变化更剧烈,从空间变化看,处于青藏高原边缘地带的佩枯错与玛旁雍错发生的变化呈现一致性,而位于中部地带的塔若错与扎日南木错的变化也呈现一致性。     

2003-2009 年中亚地区湖泊水位变化的时空特征

利用ICESat/GLAS 卫星测高数据产品获取2003-2009 年间中亚地区24 个典型湖泊的水位信息,分析该地区湖泊水位变化的时间过程和空间特征,并结合流域内气象观测数据和冰川、水坝分布图,分析不同类型湖泊的水位变化对气候变化与人类活动的响应。结果表明,湖泊水位变化与湖泊所在流域的年均降水量的变化呈显著的正相关;冰川融水对高山封闭湖泊的变化具有重要作用,其中在青藏高原北部、帕米尔高原和天山中部有大量冰川分布的流域,湖泊水位变化与湖泊补给系数呈正相关,水位主要表现为升高或稳定的状态;而在天山和阿尔泰山高地区无冰川补给的流域,水位随湖泊补给系数的增大而呈现负变化。水利枢纽或拦水坝为人类活动对湖泊的直接影响因子,其空间分布与近年来外流湖和平原尾闾湖的水位变化有关。拦水建坝的外流湖和尾闾湖的水位下降明显,而未建拦水坝或水利枢纽的外流湖水位相对稳定,进一步印证了近年来中亚水资源过度开发造成湖泊水位下降的事实。     

纳木错流域冰川和湖泊变化对气候变化的响应

利用纳木错流域及其周边地区气象资料、地形图、遥感资料以及野外实地观测资料,对该流域过去37年来气候变化特征以及冰川、湖泊变化过程进行了分析.结果表明,自1970年以来,纳木错区域气温上升趋势明显,其中冬季升温幅度高于夏季;降水量变化冬、夏两季均呈增加趋势,但冬季增加量不显著.在整体升温的背景下,纳木错流域冰川整体呈退缩趋势.1970～2007年间,流域内冰川面积减少37.1 km~2,占流域冰川面积的18.2%,年变化率为-1.0 km~2/a.流域内扎当冰川和拉弄冰川末端GPS观测表明,1970～2008年间冰川末端分别退缩381.8 m和489.5 m,年均退缩量为10.3 m和13.4 m.1970-2007年间,纳木错湖面积增加了72.6 km~2,增加速率为2.0 km~2/a.1970-1991年、1991-2000年和2000-2007年三个阶段的年增加速率不断增大,分别为1.1、2.8、3.4 km~2/a;湖泊水在在夏季升高非常显著,与湖泊面积的扩张是一致的.     

近三十年青藏高原内流区湖泊岸线形态的时空演变

湖泊岸线形态是描述和定量表达湖泊空间分布特征的重要维度。近年来,受气候暖湿化影响,青藏高原内流区湖泊总体呈现快速扩张趋势,湖泊的动态变化不仅体现在面积、水位、水量等水文参数上,还引起湖泊形态的显著变化。基于多期湖泊分布数据,结合分形和景观生态学理论,构建了湖泊岸线形态特征量化的指标体系,对1990年以来,青藏高原内流区湖泊岸线形态的时空变化特征及其影响因素进行定量分析。结果表明：① 近三十年来青藏高原内流区湖泊的分形维数和岸线发育系数总体呈上升趋势,湖泊的近圆率在此期间呈下降趋势,湖泊长宽比指数则无明显变化。② 青藏高原内流区湖泊岸线形态的总体演变特征受到地质构造的控制,体现出一定空间自相关性,断陷湖区的湖泊岸线形态及其变化要明显复杂于坳陷湖区。区域湖泊岸线的变化幅度大致从东北向西南递减,变化幅度在可可西里地区、羌塘高原中部以及羌塘高原东南部3个区域存在空间自相关性。③ 湖泊岸线形态的变化受岸线周边的地形影响,湖滨地形落差较大的区域,湖泊岸线相对稳定,变化速度较慢。岸线指数的变化量与岸线周边1 km缓冲区内的平均高差存在幂函数关系。④ 该区域湖泊岸线形态的变化和湖泊面积的变化幅度也存在一定相关性,当湖泊处于扩张阶段时,湖泊的分形维数和岸线发育系数总体呈现增加趋势,反之减少。本研究揭示了气候暖湿化背景下青藏高原内流区湖泊岸线形态的变化格局与影响特征,讨论了湖泊岸线形态及其变化格局与湖区的地质构造,气候与水文等多个要素间的关系,丰富了湖泊动态变化研究的视角与方法,为深入理解青藏高原湖泊对气候变化的响应特征,监测湖泊变化对湖盆地貌、水系连通度以及湖滨带生态环境等影响提供了科学参考。     

三个时期青藏高原冰川补给型湖泊的变化

根据美国国家冰雪数据中心(NSIDC)发布的2012年全球冰川分布数据等资料,选取青藏高原冰川分布较集中的地区作为研究区,利用1995年、2005年和2015年3个时期Landsat TM/ETM+/OLI遥感影像数据和研究区附近气象站的气象资料,综合利用"3S"技术和统计分析方法等,研究3个时期研究区内湖泊面积与数量及其变化,从气候要素变化与冰川退缩角度分析其驱动因素。研究结果表明,3个时期研究区冰川补给型湖泊整体呈扩张态势,1995年、2005年和2015年的冰川补给型湖泊面积分别为10700.5 km~2、11910.7 km~2和12518.3 km~2;与1995年相比,2005年的湖泊数量增加了2 041个,与2005年相比,2015年的湖泊数量增加了21个;分布在研究区各流域中的冰川补给型湖泊变化状况不同,分布在羌塘高原上的湖泊扩张幅度大,分布在柴达木盆地中的湖泊呈缓慢扩张态势,分布在研究区南部雅鲁藏布江流域中的湖泊相对稳定,还有一些湖泊在萎缩。随着海拔的增加,研究区中的湖泊数量和面积都呈现类似正态分布的特征。1995~2015年期间,冰川退缩和气温上升是导致青藏高原冰川补给型湖泊面积和数量变化的主要原因。     

Changes in inland lakes on the Tibetan Plateau over the past 40 years

Inland lakes and alpine glaciers are important water resources on the Tibetan Plateau. Understanding their variation is crucial for accurate evaluation and prediction of changes in water supply and for retrieval and analysis of climatic information. Data from previous research on 35 alpine lakes on the Tibetan Plateau were used to investigate changes in lake water level and area. In terms of temporal changes, the area of the 35 alpine lakes could be divided into five groups: rising, falling-rising, rising-falling, fluctuating, and falling. In terms of spatial changes, the area of alpine lakes in the Himalayan Mountains, the Karakoram Mountains, and the Qaidam Basin tended to decrease; the area of lakes in the Naqu region and the Kunlun Mountains increased; and the area of lakes in the Hoh Xil region and Qilian Mountains fluctuated. Changes in lake water level and area were correlated with regional changes in climate. Reasons for changes in these lakes on the Tibetan Plateau were analyzed, including precipitation and evaporation from meteorological data, glacier meltwater from the Chinese glacier inventories. Several key problems, e.g. challenges of monitoring water balance, limitations to glacial area detection, uncertainties in detecting lake water-level variations and variable region boundaries of lake change types on the Tibetan Plateau were discussed. This research has most indicative significance to regional climate change.     

青藏高原内陆湖泊过去40年变化研究（英文）

Inland lakes and alpine glaciers are important water resources on the Tibetan Plateau. Understanding their variation is crucial for accurate evaluation and prediction of changes in water supply and for retrieval and analysis of climatic information. Data from previous research on 35 alpine lakes on the Tibetan Plateau were used to investigate changes in lake water level and area. In terms of temporal changes, the area of the 35 alpine lakes could be divided into five groups: rising, falling-rising, rising-falling, fluctuating, and falling. In terms of spatial changes, the area of alpine lakes in the Himalayan Mountains, the Karakoram Mountains, and the Qaidam Basin tended to decrease; the area of lakes in the Naqu region and the Kunlun Mountains increased; and the area of lakes in the Hoh Xil region and Qilian Mountains fluctuated. Changes in lake water level and area were correlated with regional changes in climate. Reasons for changes in these lakes on the Tibetan Plateau were analyzed, including precipitation and evaporation from meteorological data, glacier meltwater from the Chinese glacier inventories. Several key problems, e.g. challenges of monitoring water balance, limitations to glacial area detection, uncertainties in detecting lake water-level variations and variable region boundaries of lake change types on the Tibetan Plateau were discussed. This research has most indicative significance to regional climate change.     

近46年松木希错流域冰川和湖泊变化及原因分析

采用1:5万地形图、Landsat MSS/TM/ETM+/OLI遥感影像及数字高程模型数据,利用遥感和地理信息系统技术,并结合狮泉河、和田和于田3个气象站点1968-2013年的气温、降水量数据对松木希错流域的冰川、湖泊面积变化及其原因进行分析。结果表明：① 1968-2013年流域冰川面积不断退缩,由139.25 km²减少至137.27±0.02 km²,共减少1.98±0.02 km²,减少百分比为1.42%,2001年以后冰川退缩速度加快;② 1968-2013年松木希错面积不断扩张,由25.05 km²增加至32.62±0.02 km²,共扩张7.57±0.02 km²,扩张百分比为30.22%,且2001年之后扩张速率加快,在年代际上与冰川的退缩具有较好的耦合性;③ 1968-2013年湖面潜在蒸散量减少和降水增加分别是导致湖泊扩张的第一和第二影响因素,而升温引起的冰川、冻土融水增加有一定贡献,但影响较小且在年际尺度上不显著。     

Moraine-dammed glacial lake changes during the recent 40 years in the Poiqu River Basin, Himalayas

Glacier retreat is not only a symbol of temperature and precipitation change, but a dominating factor of glacial lake changes in alpine regions, which are of wide concern for high risk of potential outburst floods. Of all types of glacial lakes, moraine-dammed lakes may be the most dangerous to local residents in mountain regions. Thus, we monitored the dynamics of 12 moraine-dammed glacial lakes from 1974 to 2014 in the Poiqu River Basin of central west Himalayas, as well as their associated glaciers with a combination of remote sensing, topographic maps and digital elevation models (DEMs). Our results indicate that all monitored moraine-dammed glacial lakes have expanded by 7.46 km² in total while the glaciers retreated by a total of 15.29 km² correspondingly. Meteorological analysis indicates a warming and drying trend in the Nyalam region from 1974 to 2014, which accelerated glacier retreat and then augmented the supply of moraine-dammed glacial lakes from glacier melt. Lake volume and water depth changed from 1974 to 2014 which indicates that lakes Kangxico, Galongco, and Youmojanco have a high potential for outburst floods and in urgent need for continuous monitoring or artificial excavation to release water due to the quick increase in water depths and storage capacities. Lakes Jialongco and Cirenmaco, with outburst floods in 1981 and 2002, have a high potential risk for outburst floods because of rapid lake growth and steep slope gradients surrounding them.     

1990-2011年西昆仑峰区冰川变化的遥感监测

本文应用Landsat 5、7 TM、ETM+影像分析1990-2011年昆仑山西段昆仑峰区冰川变化特征,结果表明:1990-2011年冰川面积减少16.83 km²,退缩率仅为0.65%,冰川退缩趋势不明显。单条冰川变化有进有退,中峰冰川末端在2002-2004年以661 m/a的速率前进,初步判定为跃动冰川。1991-1998年,崇测冰川面积增加9.47 km²,冰川末端以200 m/a的速率前进,不排除有跃动冰川的可能性。尽管近年来全球气温普遍上升,大量冰川处于退缩状态,但统计已有研究结果发现近50年来青藏高原存在冰川长度、面积增加,冰川物质平衡为正的现象,表现出冰川对气候变化复杂的反馈机制。通过分析气象站点和冰芯资料,研究区周边地区气温上升、降水量缓慢增加可能是冰川微弱退缩的原因之一;增强的西风环流带来更多的降水、研究区以极大陆型大规模冰川为主,也可能是冰川退缩幅度较小的原因。     

Glacier area changes in the Nujiang-Salween River Basin over the past 45 years

Automated image classification and visual interpretation of Landsat imagery were used to extract the glacier boundary in the Nujiang-Salween River Basin (NSRB) around the years 1975, 2000, and 2020. The spatiotemporal characteristics of glacier area changes in the NSRB were determined and the reasons for the spatial heterogeneity in glacier area changes were discussed, based on comparative analyses of temperature and precipitation data from meteorological stations around the NSRB. The results indicate that 1) the total glacier area in the NSRB decreased by 477.78 km² (28.17%) at a rate of -0.62%/a in 1975-2020. Most shrinkage occurred at low and mid altitudes, with the most severe occurring at 5290-5540 m, accounting for 40% of the total shrinkage. Considering other river basins in China, the relative glacier area change rate in the NSRB was similar to that for typical inland river basins in northwest China but lower than that for other transboundary river basins in the southeastern Tibetan Plateau. 2) These areal changes in the NSRB presented obvious regional differences. The glaciers in the Hengduan Mountains retreated significantly, followed by those in the Nyainqentanglha Mountains, with relatively low shrinkage observed in the Tanggula Mountains. The number of cold and hot spots indicating areal changes increased after 2000, along with their spatial heterogeneity. 3) The glacier shrinkage rate over different time intervals was positively correlated with temperature. Thus, spatial heterogeneity of climate change effects could elucidate differences in the glacier area change rate in different regions of the NSRB. The temperature rise was determined as the primary reason for the significant glacial retreat over the past 45 years. As the significant warming trend continues, the glacier area in the NSRB is likely to shrink further.     

西藏玛旁雍错流域冰川与湖泊变化及其对气候变化的响应

利用遥感和地理信息系统技术,基于1974,1990,1999和2003年4个不同时期的遥感影像,包括Landsat系列影像,ASTER影像和地形图,研究了玛旁雍错流域(面积7786 km²)内冰川与湖泊的变化及其对气候变化的响应。研究结果表明,由于气候变暖,在过去30年里该流域冰川和湖泊都以退为主,有进有退。自1974年到2003年,冰川面积从107.92 km²减少到100.39 km²,冰川退缩明显加速。由于年降水量减少、蒸发量增大,30年中湖泊总面积从782.24 km²减少到748.08 km²。湖面的缩小与扩涨都在加速,尤其是小湖泊变化更明显,湖泊的加速变化可能是青藏高原高海拔内陆流域水循环过程加速的表征之一。     

Paleolimnological records of recent glacier recession in the Rwenzori Mountains,Uganda-D. R. Congo

The status of tropical glaciers is enormously important to our understanding of past, present, and future climate change, yet lack of continuous quantitative records of alpine glacier extent on the highest mountains of tropical East Africa prior to the 20th century has left the timing and drivers of recent glacier recession in the region equivocal. Here we investigate recent changes (the last 150–700 years) in lacustrine sedimentation, glacier extent, and biogeochemical processes in the Rwenzori Mountains (Uganda- Democratic Republic of Congo) by comparing sedimentological (organic and siliciclastic component determined by loss-on-ignition; LOI) and organic geochemical profiles (carbon and nitrogen abundance, ratio, and isotopic composition of sedimentary organic matter) from lakes occupying presently glaciated catchments against similar profiles from lakes located in catchments lacking glaciers. The siliciclastic content of sediments in the ‘glacial lakes’ significantly decreases towards the present, whereas ‘non-glacial lakes’ generally show weak trends in their siliciclastic content over time, demonstrating that changes in the siliciclastic content of glacial lake sediments primarily record fluctuations in glacier extent. Radiometric dating of our sediment cores indicates that prior to their late 19th-century recession Rwenzori glaciers stood at expanded ‘Little Ice Age’ positions for several centuries under a regionally dry climate regime, and that recession was underway by 1870 AD, during a regionally wet episode. These findings suggest that the influence of late 19th century reductions in precipitation in triggering Rwenzori glacier recession is weaker than previously thought. Our organic geochemical data indicate that glacier retreat has significantly affected carbon cycling in Afroalpine lakes, but trends in aquatic ecosystem functioning are variable among lakes and require more detailed analysis.     

近20年天山地区冰湖变化特征

主要基于Landsat TM/ETM+影像等数据,分析1990-2010 年来天山地区冰湖变化特征及其对冰川融水径流的影响。近20 年来,天山冰湖面积平均以0.689 km²a^-1 或0.8% a^-1的速度扩张,其中一半以上是由东天山(0.352 km² a^-1) 贡献的,其次为北天山,面积年均增率为0.165km² a^-1,西天山和中央天山的面积年均增率最小,分别为0.089 km² a^-1和0.083 km² a^-1。除在相对较低海拔(< 2900 m) 和高海拔(> 4100 m) 范围内冰湖面积出现减少的现象,其他各高度带的冰湖面积均在扩张,其中增率最快的在3500~3900 m之间,平均增速达1.6% a^-1。冰湖扩张是本区气候变暖和冰川普遍退缩共同作用的结果,以中小规模的冰湖(< 0.6 km²) 对冰川退缩响应最为敏感。冰湖扩张能在一定程度上延缓因气候变暖而导致的区域冰川水资源的亏损,每年大约有0.006 Gt 的冰川融水滞留在冰湖中,约占天山冰川年消融量的2‰,但也将加剧本区冰湖溃决洪水/泥石流灾害的频次和强度。