沙尘对天山积雪消融的影响

积雪是西北干旱区重要的水资源,春季融雪时期,沙尘天气频繁,沙尘沉降会减少积雪表面反射率,增加雪层的太阳辐射吸收,加速积雪的融化,影响干旱区年内的水资源分布。通过融雪期在天山积雪雪崩研究站开展模拟沙尘沉降试验,观测积雪物理特性参数变化,分析沙尘对积雪消融的影响。本研究设置2 g·m^-2、4 g·m^-2、8 g·m^-2、自然雪4个处理,3组重复,从3月4日开始,3月11日结束。结果表明：沙尘沉降对积雪消融具有明显影响。在2 g·m^-2、4 g·m^-2、8 g·m^-2沙尘沉降量下,随着融雪的进行,沙尘沉降量逐渐增大,致使积雪表面粒径增大,积雪反射率降低,雪表层温度差变大,2 g·m^-2、4 g·m^-2、8 g·m^-2导致积雪消融速率比自然状态下的快22.36%、46.05%和76.90%。通过野外试验获得了主要积雪物理参数对沙尘沉降的响应,量化了沙尘沉降对积雪消融的影响,其结果可为西北干旱区水资源管理提供参考。     

天山云杉雪盖面积估算树冠截留雪水当量实验分析

雪水当量是一个能直观反映出积雪水资源量的重要指标,准确而全面地获取天山云杉树冠截留雪水当量信息,对于提高天山水资源量计算精度方面具有重要意义。本文以天山云杉树苗为研究对象,通过模拟降雪,进行降雪截留实验研究。利用数码照相机获取云杉的雪盖面积、高精度天平称量树冠上截留的雪水质量,进而建立起云杉树苗雪盖面积和雪水当量之间的关系。实验结果表明:多株云杉树苗多次模拟降雪,树冠截留的雪水当量和垂直朝下数字摄影获得的雪盖面积之间拟合曲线趋于一致,且拟合回归方程满足y=21.235χ^2-1.457χ(R^2=0.992 5);通过云杉多次模拟降雪实验,构建云杉雪盖面积与树冠截留的雪水当量模型,提出一套利用雪盖面积较为准确估算树冠截留雪水当量的科学方法,为天山云杉树冠截留降雪及其雪水当量提供高精度估算模型。     

天山北坡典型内陆河流域积雪年内分配与年际变化研究——以玛纳斯河流域为例

以500m分辨率的MOD10A2积雪遥感影像和气象站点数据为基础,以积雪覆盖率和初雪日与积雪日数为变量对玛纳斯河流域积雪的年内分配(2007年10月-2008年9月)与年际变化(1960年-2006年)进行了分析探讨.结果表明:水文年内玛纳斯河流域积雪变化较大,北部开阔的河谷地带积雪覆盖呈现明显的季节性变化;南部山区海...     

西天山小流域动态融雪过程及其与气温的关系

利用西天山阿热都拜小流域积雪、融雪和气象观测场2017-2018年每30 min的同步降雪、融雪和气温观测数据,对全年积雪期较短时间尺度上的融雪动态过程及其与气温的关系进行了对比分析。结果表明:山区降雪表现为"先升后降"的总体特征。稳定积雪期集中在2017年12月27日至2018年3月8日,最大降雪速率高达9. 6mm·h^-1(雪水当量值,转化成新鲜雪深值为96. 5 mm·h^-1)。山区融雪过程的变化规律与降雪变化正好相反,呈现出"先降后升"的变化特征。融雪变化分为3个阶段,第一阶段:随着气温的下降,融雪速率下降,融雪速率由3. 24 mm·h^-1逐渐下降至0 mm·h^-1;第二阶段:当气温低于融雪的临界温度(-13. 5-12. 0℃)时,不产生融雪;第三阶段:随着气温的回升,融雪速率从0 mm·h^-1逐渐上升至3. 87 mm·h^-1。在全年融雪与气温的大数据关系中,融雪量与气温的相关性系数不是很显著,其相关性系数为0. 708;在无降水干扰下,7 d平均同步融雪量与气温的相关性系数处于显著水平,Pearson相关性系数为0. 907,R^2=0. 823;当进一步考虑滞后效应后,融雪量与气温的相关性系数提升至极显著的线性关系,相关性系数高达0. 943,R^2=0. 889,均通过了0. 01显著性水平的双尾检验。在西天山阿热都拜小流域融雪量的变化过程与气温的变化过程有着密切的相关性。这种融雪量对气温变化的响应关系及其分析方法,对于提高应对未来气候变化的能力和预防洪灾及水资源管理具有一定的参考价值。     

天山北坡山区流域融雪径流模拟研究

天山北坡山区流域资料稀缺,融雪径流模拟比较困难。以天山北坡的乌鲁木齐河、玛纳斯河和奎屯河流域为例,利用水文气象资料和冰雪遥感数据,建立流域融雪径流SRM模型,以2007年3—8月为模拟校准期,2005年和2006年3—8月为模拟检验期,模拟3个资料稀缺山区流域融雪日径流,检验模拟结果和模型的有效性,评价SRM模型在资料稀缺流域的适用性。结果表明:3个流域SRM模型融雪径流模拟具有比较好的模拟效果。在模拟校准期间,3个流域R2平均值为0.85,D_V平均值为9.42%,模拟精度比较高;在模拟检校期,2006年3个流域R~2平均值为0.72,D_V平均值为13.3%,2005年R~2平均值为0.78,D_V平均值为4.85%,表明3个流域SRM模型的参数估算合理,建立的SRM模型是有效的,SRM模型在天山北坡的资料稀缺山区流域融雪径流模拟中具有其适用性。     

Glacier mass balance and its impacts on streamflow in a typical inland river basin in the Tianshan Mountains,northwestern China

Glaciers are known as natural 'solid reservoirs', and they play a dual role between the composition of water resources and the river runoff regulation in arid and semi-arid areas of China. In this study, we used in situ observation data from Urumqi Glacier No. 1, Xinjiang Uygur Autonomous Region, in combination with meteorological data from stations and a digital elevation model, to develop a distributed degree-day model for glaciers in the Urumqi River Basin to simulate glacier mass balance processes and quantify their effect on streamflow during 1980-2020. The results indicate that the mass loss and the equilibrium line altitude (ELA) of glaciers in the last 41 years had an increasing trend, with the average mass balance and ELA being -0.85 (±0.32) m w.e./a (meter water-equivalent per year) and 4188 m a.s.l., respectively. The glacier mass loss has increased significantly during 1999-2020, mostly due to the increase in temperature and the extension of ablation season. During 1980-2011, the average annual glacier meltwater runoff in the Urumqi River Basin was 0.48×10⁸ m³, accounting for 18.56% of the total streamflow. We found that the annual streamflow in different catchments in the Urumqi River Basin had a strong response to the changes in glacier mass balance, especially from July to August, and the glacier meltwater runoff increased significantly. In summary, it is quite possible that the results of this research can provide a reference for the study of glacier water resources in glacier-recharged basins in arid and semi-arid areas.     

天山乌鲁木齐河源区空冰斗积雪特征

根据2006年12月至2007年4月天山乌鲁木齐河源区空冰斗季节性积雪的观测资料,分析了该区域积雪厚度、积雪温度及积雪储水量的变化特征。结果表明:空冰斗积雪在观测初期比较稳定,随着降水量增加,积雪厚度也随之增加,4月中旬达到最大值,季节性积雪的持续时间约为7个月;积雪厚度最大值一般出现在海拔3830m附近,这一高度以下积雪厚度随海拔升高呈现增加的趋势,而在这一高度以上则呈相反趋势;积雪温度受气温影响明显,在观测期内随着气温的升高积雪温度也逐渐上升;研究期内积雪储水量高于上世纪90年代初的同期观测值。     

Spatiotemporal variation in snow cover and its effects on grassland phenology on the Mongolian Plateau

Snow cover is an important water source for vegetation growth in arid and semi-arid areas,and grassland phenology provides valuable information on the response of terrestrial ecosystems to climate change.The Mongolian Plateau features both abundant snow cover resources and typical grassland ecosystems.In recent years,with the intensification of global climate change,the snow cover on the Mongolian Plateau has changed correspondingly,with resulting effects on vegetation growth.In this study,using MOD10A1 snow cover data and MOD13A1 Normalized Difference Vegetation Index(NDVI)data combined with remote sensing(RS)and geographic information system(GIS)techniques,we analyzed the spatiotemporal changes in snow cover and grassland phenology on the Mongolian Plateau from 2001 to 2018.The correlation analysis and grey relation analysis were used to determine the influence of snow cover parameters(snow cover fraction(SCF),snow cover duration(SCD),snow cover onset date(SCOD),and snow cover end date(SCED))on different types of grassland vegetation.The results showed wide snow cover areas,an early start time,a late end time,and a long duration of snow cover over the northern Mongolian Plateau.Additionally,a late start,an early end,and a short duration were observed for grassland phenology,but the southern area showed the opposite trend.The SCF decreased at an annual rate of 0.33%.The SCD was shortened at an annual rate of 0.57 d.The SCOD and SCED in more than half of the study area advanced at annual rates of 5.33 and 5.74 DOY(day of year),respectively.For grassland phenology,the start of the growing season(SOS)advanced at an annual rate of 0.03 DOY,the end of the growing season(EOS)was delayed at an annual rate of 0.14 DOY,and the length of the growing season(LOS)was prolonged at an annual rate of 0.17 d.The SCF,SCD,and SCED in the snow season were significantly positively correlated with the SOS and negatively correlated with the EOS and LOS.The SCOD was significantly negatively correlated with the SOS and positively correlated with the EOS and LOS.The SCD and SCF can directly affect the SOS of grassland vegetation,while the EOS and LOS were obviously influenced by the SCOD and SCED.This study provides a scientific basis for exploring the response trends of alpine vegetation to global climate change.     

秦岭主峰太白山积雪时空变化规律及驱动机制分析

利用2000-2017年LandsatTM数据,基于SNOMAP算法提取秦岭主峰太白山积雪面积,同时结合研究区地形数据及10个气象站点的气象观测数据,分析太白山积雪变化特征及其与地形、气候因素的关系.结果表明:(1)2000-2017年冷季太白山积雪面积在波动中减少.积雪面积消减率为24.15％;(2)影响太白山积雪变...     

Spatiotemporal changes of typical glaciers and their responses to climate change in Xinjiang,Northwest China

Glaciers are highly sensitive to climate change and are undergoing significant changes in mid-latitudes. In this study, we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in the period of 1990-2015 in 4 different mountainous sub-regions in Xinjiang Uygur Autonomous Region of Northwest China: the Bogda Peak and Karlik Mountain sub-regions in the Tianshan Mountains; the Yinsugaiti Glacier sub-region in the Karakorum Mountains; and the Youyi Peak sub-region in the Altay Mountains. The standardized snow cover index (NDSI) and correlation analysis were used to reveal the glacier area changes in the 4 sub-regions from 1990 to 2015. Glacial areas in the Bogda Peak, Karlik Mountain, Yinsugaiti Glacier, and Youyi Peak sub-regions in the period of 1990-2015 decreased by 57.7, 369.1, 369.1, and 170.4 km², respectively. Analysis of glacier area center of gravity showed that quadrant changes of glacier areas in the 4 sub-regions moved towards the origin. Glacier area on the south aspect of the Karlik Mountain sub-region was larger than that on the north aspect, while glacier areas on the north aspect of the other 3 sub-regions were larger than those on the south aspect. Increased precipitation in the Karlik Mountain sub-region inhibited the retreat of glaciers to a certain extent. However, glacier area changes in the Bogda Peak and Youyi Peak sub-regions were not sensitive to the increased precipitation. On a seasonal time scale, glacier area changes in the Bogda Peak, Karlik Mountain, Yinsugaiti Glacier, and Youyi Peak sub-regions were mainly caused by accumulated temperature in the wet season; on an annual time scale, the correlation coefficient between glacier area and annual average temperature was -0.72 and passed the significance test at P<0.05 level in the Karlik Mountain sub-region. The findings of this study can provide a scientific basis for water resources management in the arid and semi-arid regions of Northwest China in the context of global warming.     

1960-2009年中国天山现代冰川末端变化特征

基于冰川定位观测、野外考察、航空摄影、遥感影像和地形图分析方法,研究了1960-2009年中国天山8条冰川末端变化特征。结果表明：1960-2009年,在天山地区气温与降水呈上升趋势的背景下,8条冰川均处于退缩状态,退缩速率由西向东逐渐减缓,其变化幅度因气候环境、地理位置、冰川规模和冰川形态等的不同而存在明显的区域性与阶段性差异。其中,乌鲁木齐河源1号冰川1962-1973年冰川末端退缩速率为5.96 m•a^-1,1973-1980年为3.28 m•a^-1,1980-1993年为3.93 m•a^-1,在1993年完全分离成东、西两支独立的冰川;博格达峰四工河4号冰川末端1962-1981年退缩速率为6 m•a^-1,1981-2006年为8.9 m•a^-1,2006-2009年为13.3 m•a^-1。表碛覆盖的青冰滩72号冰川和74号冰川末端1964-2009年退缩速率分别为41 m•a^-1和30 m•a^-1,远较无表碛覆盖的庙儿沟平顶冰川退缩迅速（1972-2007年冰川末端退缩速率为2.32 m•a^-1）。表面特征（表碛）亦是造成冰川变化差异的一个主要原因。     

Fluxes of methane,carbon dioxide and nitrous oxide in an alpine wetland and an alpine grassland of the Tianshan Mountains,China

Methane(CH4), carbon dioxide(CO2) and nitrous oxide(N2O) are known to be major greenhouse gases that contribute to global warming. To identify the flux dynamics of these greenhouse gases is, therefore, of great significance. In this paper, we conducted a comparative study on an alpine grassland and alpine wetland at the Bayinbuluk Grassland Eco-system Research Station, Chinese Academy of Sciences. By using opaque, static, manual stainless steel chambers and gas chromatography, we measured the fluxes of CH4, N2O and CO2 from the grassland and wetland through an in situ monitoring study from May 2010 to October 2012. The mean flux rates of CH4, N2O and CO2 for the experimental alpine wetland in the growing season(from May to October) were estimated at 322.4 μg/(m2?h), 16.7 μg/(m2?h) and 76.7 mg/(m2?h), respectively; and the values for the alpine grassland were –88.2 μg/(m2?h), 12.7 μg/(m2?h), 57.3 mg/(m2?h), respectively. The gas fluxes showed large seasonal and annual variations, suggesting weak fluxes in the non-growing season. The relationships between these gas fluxes and environmental factors were analyzed for the two alpine ecosystems. The results showed that air temperature, precipitation, soil temperature and soil moisture can greatly influence the fluxes of CH4, N2O and CO2, but the alpine grassland and alpine wetland showed different feedback mechanisms under the same climate and environmental conditions.     

天山奎屯哈希勒根51号冰川变化及其对气候的响应

哈希勒根51号冰川位于新疆奎屯市以南的天山依连哈比尔尕山北坡,即奎屯河上游支流哈希勒根河源区。继1998年对冰川末端和运动速度的首次观测之后,相继开展了多次重复测量,完成了冰川面积测量和首次雷达厚度测量。结合冰川实测资料和已有相关研究,对自20世纪60年代以来的变化特征进行了详细分析,结果表明：1964-2006年哈希勒根51号冰川面积共减小了0.123 km2,年平均退缩率约为0.19%,相比低于天山地区的整体水平（0.31%）。冰川末端累计退缩84.51 m,年平均退缩率为2.01 m。对于冰川运动速度,1999-2006年整体偏低,各流速点的年际变化较小,且略微有下降的趋势;7 a间物质平衡年际变化较小,整体表现出沿海拔高度增加而增加的趋势。1964-2010年冰川厚度减薄了约10 m,年均变化率约为0.22 m。与天山乌鲁木齐河源1号冰川相比,整体消融趋势稍弱。     

天山北坡融雪期土壤湿度特征及其影响因子

以天山北坡军塘湖流域为研究区,测量2009年和2010年该地区不同深度土壤湿度的变化,并对2 a融雪期各土壤湿度进行比较。结果表明：2 a间 0 cm和10 cm土壤湿度变化趋势一致,20 cm和30 cm土壤湿度变化差异较大。运用相关分析方法,分析2009年各层土壤湿度与2 m气温、土壤温度及雪深的关系,得出各层土壤湿度变化是气温、雪深和土壤温度综合作用的结果,但在不同时期不同深度土壤湿度所受的影响因子不同。同时分析了2009年和2010年不同土壤湿度特征与融雪洪水洪峰的关系,得出在融雪期,若下层（20 cm以下）土壤湿度变化小则出现洪水,反之则无洪水。其结果为进一步研究融雪径流模型和洪水径流预报提供基础资料。     

Economic losses from reduced freshwater under future climate scenarios: An example from the Urumqi River,Tianshan Mountains

As important freshwater resources in alpine basins, glaciers and snow cover tend to decline due to climate warming, thus affecting the amount of water available downstream and even regional economic development. However, impact assessments of the economic losses caused by reductions in freshwater supply are quite limited. This study aims to project changes in glacier meltwater and snowmelt of the Urumqi River in the Tianshan Mountains under future climate change scenarios (RCP2.6 (RCP, Representative Concentration Pathway), RCP4.5, and RCP8.5) by applying a hydrological model and estimate the economic losses from future meltwater reduction for industrial, agricultural, service, and domestic water uses combined with the present value method for the 2030s, 2050s, 2070s, and 2090s. The results indicate that total annual glacier meltwater and snowmelt will decrease by 65.6% and 74.5% under the RCP4.5 and RCP8.5 scenarios by the 2090s relative to the baseline period (1980-2010), respectively. Compared to the RCP2.6 scenario, the projected economic loss values of total water use from reduced glacier meltwater and snowmelt under the RCP8.5 scenario will increase by 435.10×10⁶ and 537.20×10⁶ CNY in the 2050s and 2090s, respectively, and the cumulative economic loss value for 2099 is approximately 2124.00×10⁶ CNY. We also find that the industrial and agricultural sectors would likely face the largest and smallest economic losses, respectively. The economic loss value of snowmelt in different sectorial sectors is greater than that of glacier meltwater. These findings highlight the need for climate mitigation actions, industrial transformation, and rational water allocation to be considered in decision-making in the Tianshan Mountains in the future.     

新疆霍城地区树轮年表的建立及气候意义

通过对霍城地区5个树轮年表多项统计特征参数的对比,表明差值树轮年表对气候变化研究具有应用潜力.在5个差值树轮年表中,阿里比萨依和霍尔果斯年表包含了较多的气候信息.将5个差值树轮年表与附近的霍城和霍尔果斯气象站1960-2005年逐月降水和气温资料进行相关普查.结果发现:2个低海拔树轮差值年表的平均年表与2站当年5月降水呈正相关,且相关性好;而3个上树线树轮差值年表的平均年表与2站上年12月的平均气温呈正相关,且相关性好,其正相关均具有明显的树木生理学意义.对代表性较好的阿里比萨依差值树轮年表进行31年滑动平均发现,其年轮指数具有6高5低的阶段性变化,其变化与伊犁河1818-1990年的丰枯变化具有较好的一致性.     

新疆伊犁地区夏季平均最高气温的重建和分析

根据采自伊犁地区天山的树木年轮样本,建立了该地区的树轮年表。通过单相关普查发现,自回归树轮年表序列与夏季(6~8月)的平均最高气温呈明显的负相关关系。并且具有明确的树木生理学意义。利用新源上限(XNAUt 1)、巩留下限(GUt 1)和特克斯上限(TUt 1)3个自回归树轮年表序列,可较好地重建伊犁天山东部在该时段的月平均最高气温。经交叉检验可知,所得重建方程是稳定可靠的,重建的温度序列是可信的。通过分析发现:伊犁天山东部300年来夏季月平均最高气温大致经历了8个偏暖阶段和8个偏冷阶段;具有2.9,3.4,4,49.5,58,59,68年的变化准周期;存在5次气温突变:1729-1733年、1867-1871年、1929-1934年前后气温由高向低突变;1841-1846年、1903-1906年前后气温由低向高突变。     

Climate change in the Tianshan and northern Kunlun Mountains based on GCM simulation ensemble with Bayesian model averaging

Climate change in mountainous regions has significant impacts on hydrological and ecological systems. This research studied the future temperature, precipitation and snowfall in the 21~(st) century for the Tianshan and northern Kunlun Mountains(TKM) based on the general circulation model(GCM) simulation ensemble from the coupled model intercomparison project phase 5(CMIP5) under the representative concentration pathway(RCP) lower emission scenario RCP4.5 and higher emission scenario RCP8.5 using the Bayesian model averaging(BMA) technique. Results show that(1) BMA significantly outperformed the simple ensemble analysis and BMA mean matches all the three observed climate variables;(2) at the end of the 21~(st) century(2070–2099) under RCP8.5, compared to the control period(1976–2005), annual mean temperature and mean annual precipitation will rise considerably by 4.8°C and 5.2%, respectively, while mean annual snowfall will dramatically decrease by 26.5%;(3) precipitation will increase in the northern Tianshan region while decrease in the Amu Darya Basin. Snowfall will significantly decrease in the western TKM. Mean annual snowfall fraction will also decrease from 0.56 of 1976–2005 to 0.42 of 2070–2099 under RCP8.5; and(4) snowfall shows a high sensitivity to temperature in autumn and spring while a low sensitivity in winter, with the highest sensitivity values occurring at the edge areas of TKM. The projections mean that flood risk will increase and solid water storage will decrease.     

Response of ecosystem service value to land use/cover change in the northern slope economic belt of the Tianshan Mountains,Xinjiang, China

Land use/cover change (LUCC) is becoming more and more frequent and extensive as a result of human activities, and is expected to have a major impact on human welfare by altering ecosystem service value (ESV). In this study, we utilized remote sensing images and statistical data to explore the spatial-temporal changes of land use/cover types and ESV in the northern slope economic belt of the Tianshan Mountains in Xinjiang Uygur Autonomous Region, China from 1975 to 2018. During the study period, LUCC in the study region varied significantly. Except grassland and unused land, all the other land use/cover types (cultivated land, forestland, waterbody, and construction land) increased in areas. From 1975 to 2018, the spatial-temporal variations in ESV were also pronounced. The total ESV decreased by 4.00×10⁸ CNY, which was primarily due to the reductions in the areas of grassland and unused land. Waterbody had a much higher ESV than the other land use/cover types. Ultimately, understanding the impact of LUCC on ESV and the interactions among ESV of different land use/cover types will help improve existing land use policies and provide scientific basis for developing new conservation strategies for ecologically fragile areas.     

近20 a中国天山东段典型冰川变化及其气候响应

冰川作为重要的淡水资源的存储体,也是气候变化的敏感"指示器"。在干旱半干旱区,冰川变化对人们的生产、生活和生态产生重要的影响。本文基于1990—2015年Landsat TM及ETM+遥感影像数据,利用雪盖指数法(NDSI)和阈值法,分析博格达峰及喀尔力克山的冰川面积变化,结合长时间序列的气温、降水数据分析天山东段典型冰川的气候响应。结果表明:(1)博格达峰与喀尔力克山的冰川均呈现退缩趋势,与气温和降水的变化趋势一致。(2)博格达峰和喀尔力克山冰川面积变化在东南坡向有波动增加趋势,其他坡向则未出现该现象。(3)从两个冰川不同坡向的面积和面积重心分布变化分析,博格达峰冰川面积在东坡方向退缩速率最大,而喀尔力克山的冰川在东北坡方向退缩速率最大。(4)根据栅格气象资料分析,近四五十年博格达地区冰川面积退缩速率大于喀尔力克山地区,并且博格达峰降水量的增加对冰川的退缩起到的作用不大,喀尔力克山的降水量对冰川面积的退缩起到了一定的抑制作用。(5)通过对博格达峰地区和喀尔力克山地区不同坡向的冰川面积与年均气温、年均降水量进行Person相关性分析,博格达峰地区、喀尔力克山地区各个坡向的冰川面积变化与降水相关系数均很小。但博格达峰地区北、东北、东南坡向的冰川面积与区域气温变化相关系数较高,喀尔力克山地区东南、东北坡向的冰川面积与区域气温的相关系数高且显著性明显。分析其原因,在年内尺度上,博格达峰地区、喀尔力克山地区是湿季气温升高所致,干湿两季降水量的增多,并没有使得冰川整体的退缩有所减缓。