祁连山冷龙岭宁缠河3号冰川表面流速特征分析

2009年9月对祁连山冷龙岭宁缠河3号冰川外围建立控制网, 于冰川表面布设了13根标志杆, 随后分别于2010年7月、2010年9月再次对设立在冰川表面的花杆点进行测量, 获取2009/2010年度、2009年9月-2010年7月与2010年7-9月3个时段宁缠河3号冰川表面流速.结果显示: 2009/2010年度宁缠河3号冰川最大流速出现在海拔4 430 m附近, 为3.76 m·a^-1;2009年9月-2010年7月表面流速最大值出现在海拔4 430 m附近, 为0.32 m·月^-1;2010年7-9月最大流速出现在海拔4 380 m附近, 为0.47 m·月^-1.总体来看, 2009/2010年度宁缠河3号冰川纵剖面上流速变化较为缓和, 显示出流速随海拔变化而变化的规律. 但不同季节表面流速在纵剖面上的分布情况不同, 横剖面上主流线附近流速最大, 向冰川两边逐渐递减, 各观测点均平行于主流线方向向冰川末端运动, 表现出冰川运动一般规律. 在冰川表面运动速度观测区域内东南边缘流速略大于西北边缘, 同时与规模相近的冰川运动速度相比, 宁缠河3号冰川运动速度较大.     

无人机在冰川变化监测中的应用——以唐古拉山小冬克玛底冰川为例

近年来,无人机技术发展迅速。无人机的灵活、便携、超高分辨率等特性使其在冰川变化监测上具有很好的发展前景。论文以青藏高原腹地的唐古拉山小冬克玛底冰川为例,首次在海拔5400 m以上的地区开展了无人机航测,通过非冰川区的基岩对2019年7月20日、2019年9月27日和2020年7月16日3期航测产品进行相对校正,分析了小冬克玛底冰川在物质平衡年和消融期内的变化情况,并进一步讨论了无人机在冰川区观测时所遇到的问题及其优势,以期为后续研究提供参考。结果表明:利用无人机技术能够实现冰川在消融期内的末端、面积以及高程变化监测,并对冰川的细部特征进行分析,适合于小区域单条冰川的变化监测。     

1968-2009年叶尔羌河流域冰川变化——基于第一、二次中国冰川编目数据

利用"中国冰川资源及其变化调查"项目最新冰川编目成果和中国第一次冰川编目结果, 对中国叶尔羌河流域1968-2009年冰川变化进行了分析. 结果表明:叶尔羌河流域冰川总体上处于退缩状态, 面积减少了927 km², 年平均面积减少23.2 km², 年均面积缩小比例为0.36%·a^-1, 与中国其他地区冰川退缩程度相比属于中等水平. 叶尔羌河流域不同规模冰川的退缩幅度存在差异, 小冰川大幅萎缩, 甚至消失; 规模较大的冰川相对变化幅度较小, 一些冰川出现过跃动. 从朝向分布来看, 位于南坡的冰川退缩最为严重, 而西坡较小. 冰川集中分布在海拔5 100~5 500 m和5 500~5 900 m区间, 海拔4 700~5 100 m区间的冰川面积减少最为显著. 消失冰川大多数为面积在0.2~0.5 km²的小冰川, 且朝向东北坡的冰川消失数量最多. 研究区有冰川分裂现象, 也出现了支冰川前进超覆现象, 统计表明该流域有13条冰川在前进后形成6条冰川. 1968-2009年研究区气温升高、降水增加, 总体上看, 降水增加缓解了因升温而导致的冰川退缩.     

1959-2017年天山乌鲁木齐河源1号冰川流域径流及其组分变化

冰川是气候变化的指示器,气候变化对冰川及其径流的影响研究是目前国内外关注的热点和前沿领域之一,目前的研究以模拟为主,实测资料十分有限且不确定性很大。以新疆天山乌鲁木齐河源1号冰川（简称“1号冰川”）流域为例,基于中国科学院天山冰川观测试验站1959-2017年观测数据,研究了中国西部典型小型冰川流域径流及其组分长期变化以及对气候变化的响应,为冰川径流长期变化过程的认识提供重要参考。结果表明,1号冰川流域径流主要由冰川径流和非冰川区降水径流组成,分别占70%和30%。其中冰川径流又可分为冰川区降水径流和冰川融水径流,分别占44%和26%。59年间,冰川径流整体呈上升趋势,在1992年之后出现了一个阶梯式的上升,与气温升高和降水的增加有关,1997-2007年达到高峰,2008年以后出现波动下降趋势,其原因除了与该时段的降水有所减少有关之外,冰川面积减小的影响也不可忽视。另外,还利用实测径流和冰川物质平衡值,通过水量平衡模型,检验了模型使用的冰川区和非冰川区径流系数。     

天山哈密庙尔沟平顶冰川和奎屯河哈希勒根51号冰川成冰带与雪层pH值和电导率对比研究

对天山哈密庙尔沟平顶冰川和奎屯河哈希勒根51号冰川的雪层剖面及雪坑中pH值和电导率的变化特征进行了初步研究.结果表明:哈密庙尔沟平顶冰川以渗浸-冻结成冰作用为主,一年成冰,成冰带由消融带和渗浸-冻结带组成,渗浸-冻结带的垂直高度在60 m左右或者更大一点;奎屯河哈希勒根51号冰川的成冰作用以暖型为主,成冰带由消融带、渗浸-冻结带和渗浸带组成,渗浸-冻结带的垂直高度不大于70 m.雪坑中pH值和电导率的较高值一般出现在冰片和污化层附近,这与冰的阻碍、引起可溶性离子在冰面上部的高浓度值和可溶性离子的淋溶过程与污化物的迁移过程密切联系直接相关.哈密庙尔沟平顶冰川雪坑中pH值和电导率之间的相关性异于奎屯河哈希勒根51号冰川,由于雪坑的资料有限,有待进一步的深入研究.     

珠穆朗玛峰北坡东绒布冰川成冰作用的新认识

冰川成冰作用的研究对于选择冰芯钻取点具有重要的科学意义。前人对珠穆朗玛峰北坡冰川成冰作用的研究,由于缺少高海拔区域的实测资料而具有一定的局限性。文章通过1998年东绒布冰川垭口处(6 500 m a. s. l.)11 m冰芯和海拔6 450 m处20 m冰芯剖面的成冰作用过程研究,认识到由于水、热条件的逐年波动,冰川成冰作用也处于变化之中。珠穆朗玛峰北坡东绒布冰川高海拔区域,在一定的水、热条件下(如气温较低和降水量较大等),再冻结-重结晶作用依然占主导地位,该成冰作用至少在垭口部位是有分布的。而一般在气温较高或降水量较少等条件下,冰川的成冰作用则以冷渗浸-重结晶作用为主。     

天山南坡科其喀尔巴西冰川消融估算

能量平衡模型是目前估算冰川表面消融最准确的方法之一.利用科其喀尔巴西冰川野外气象和消融观测数据,结合1:5万地形图,对不同坡向和坡度格点上总辐射和净辐射进行了地形校正模拟,并采用空气动力学法对冰面感热和潜热进行了计算,最后对冰川表面消融进行了模拟.结果表明,模拟小时总辐射和实测值存在较好的一致性,二者相关系数为0.85,而净辐射模拟效果较差.消融模拟值大体反映了实际的消融值,平均误差为2.9mm w.e/day,均方根误差为4.2 mm w.e/day,且模拟值一般略大于观测值,距离自动气象站较近的花杆模拟相对误差较小,随着花杆距离冰面自动气象站距离的增大,模拟相对误差呈增加的趋势.     

Study on mass balance and sensitivity to climate change in summer on the Qiyi Glacier, Qilian Mountains

Based on the glacier mass balance and meteorological data of air temperature and precipitation on the Qiyi Glacier from June 30 to September 5, 2010, we used a degree-day mass balance model to simulate the change of mass balance during this period. Our results indicate that the current value of the mass balance is ?856.2 mm w.e. Subjected to the strong influences of air temperature and precipitation, the mass balance process can be divided into three stages: accumulating exiguously → melting intensively → melting exiguously. The variation trends of the mass balance according to the degree-day mass balance model and the observed values are similar and wholly reflect the spatial distribution characteristics of the glacier mass balance, which increases with the increase of altitude. Our experiment on climate sensitivity of the mass balance showed that mass balance was very sensitive to the change of temperature; air temperature is the key factor which influences mass balance; and a slight increase in precipitation will have a negligible effect on mass balance when the air temperature increases continuously.     

Permafrost distribution in the Posets massif,Central Pyrenees

The Posets massif is located in the Central Pyrenees and reaches a height of 3363 m a.s.l. at the Posets peak, the second highest massif in the Pyrenees. Geomorphological maps of scales 1:25000 and 1:10000, BTS (bottom temperature of winter snow), ground measurements and snow poles were used to observe the more representative periglacial active landform association, ground thermal regime, the winter snow cover evolution and basal temperatures of snow. The main active periglacial landforms and processes related to the ground thermal regime and snow cover were studied. Mountain permafrost up to 2700 m a.s.l. on northexposed slopes and up to 2900 m a.s.l. on south-exposed slopes were detected. Three permafrost belts were differentiated: sporadic permafrost between 2700 and 2800 m a.s.l. and between 2850 and 3000 m a.s.l., discontinuous permafrost between 2800 and 2950 and between 2950 and 3050, and continuous permafrost up to 2900 m a.s.l. and up to 3050 m a.s.l. on northern and southern slopes, respectively.     

Annual Mass Balance of Blue Glacier, USA: 1955–97

Mass changes of Blue Glacier, USA are calculated from topographic maps made from vertical aerial photography in late summer of 1939, 1952, 1957, and 1987, along with laser altimetry flown in June 1996. Changes in elevation between maps were adjusted for seasonal variations in the snow cover, and to account for the ablation between the date of photography and 1 October. Topography obtained from the laser altimetry was adjusted for snow thickness and glacier motion to estimate topography of 1 October 1995. The mass of Blue Glacier has changed less than 7 m (water equivalent) during this 56 year period which is minor compared with other glaciers in the region and elsewhere in the world. Glacier-average annual mass balances, beginning in 1956, have been calculated either from stake measurements and probing of late-season snow, or from a regression analysis using late-season measurements of the equilibrium line altitude. A comparison with the changes derived from surface maps shows values obtained from field measurements are too positive by about 0.4 m a^?1 , indicating that considerable caution is needed when interpreting time series of mass balance. Two alternative time series of mass balance consistent with the long-term mass changes are created by making simple adjustments: (1) a single constant is subtracted from each value so that the series is consistent with the 1957–95 mass change; (2) one constant is subtracted from each value over 1957–87 and another is subtracted from each value over 1987-95 so that the series is consistent with both the 1957–87 and 1987–95 mass changes. The mass balance of Blue Glacier was generally positive until the mid-1970s and negative since. The fluctuations of mass balance closely resemble those of snowfall on the glacier as estimated from the joint distribution of temperature and precipitation. The climate in western Washington was cooler and wetter during the decade before the mid-1970s, but the trend since has been towards warmer and drier conditions.