唐古拉山冬克玛底冰川反照率变化特征研究

根据夏季消融期成像的Landsat TM影像和2000-2009年间的MOD10A1数据资料, 分析了唐古拉山区冬克玛底冰川反照率的时空变化特征. 结果表明: 受空间尺度效应和现有反演方法的影响, 由遥感反演的反照率资料在数值上存在一定的误差, 但基本上能够反映冰川反照率的时空变化特征. 从空间分布上来看, 该冰川反照率随海拔升高呈增大趋势, 其中在平衡线附近的变化最为显著; 受地形因素的影响, 在同一海拔带内部也存在着较大的差异. 从年内变化上来看, 该冰川反照率日际变化波动较大, 且具有明显的季节变化特征. 从年际变化上来看, 自2000年以来该冰川年均反照率的变化波动较大, 总体呈微弱下降的趋势, 这主要与年降雪和冰面污化程度有关; 不考虑降雪对冰面反照率的影响, 2000-2009年间该冰川在消融期的反照率呈逐年减小的趋势, 变化速率约为-0.0083·a^-1, 其原因在于夏季气温的升高和冰面污化程度的加大.     

天山乌鲁木齐河源1号冰川消融期反照率特征

消融期冰川反照率特征研究对于深入理解冰川消融过程及其对气候变化的响应机理具有重要意义。利用Landsat卫星影像反演反照率数据,MODIS逐日反照率产品数据以及野外观测反照率数据,分析了天山乌鲁木齐河源1号冰川2016年消融期（5—8月）反照率时空变化特征。研究表明：消融早期,冰川反照率空间变化不明显;消融中后期,总体上呈现随海拔的升高而增大的趋势,在平衡线附近增速最快。消融期冰川反照率整体呈下降趋势,而且在6—7月份变化最为剧烈。平衡线附近反照率时间变化尤其显著,积累区次之,消融区最弱。冰川反照率的时空变化主要由冰面特征决定。气温和固态降水是其驱动因素。冰川反照率随气温的升高而降低,但固态降水会打破其随气温的变化趋势,引起反照率的增加。污化物显著降低冰面反照率,尤其在可见光波段（380~760 nm）。此外,即使冰面特征相对均一,反照率还呈现随太阳入射角的增大而增大的趋势,主要由冰川局部地形（坡度与坡向）差异所致。     

希夏邦马峰抗物热冰川区消融期气候特征

根据１９９３年夏季在希夏邦马峰抗物热冰川考察时取得的部分气象要素观测资料，结果表明，尽管夏季气温相对较高，但由于降水频繁，冰川表面降雪，通过增加冰面反射，削弱冰面消融，导致冰川水文循环水平低。温度观测揭示出受西南季风影响，夏季冰川区处于高温环境中；又由于相对远离主山脉，且无明显的山谷形态，该冰川区局地环流不发育，整个观测期间均受制于东南和南风控制之下     

Study on the spatial and temporal variations of the surface albedo on Muz Taw Glacier,Sawir Mountains北大核心CSCD

冰川反照率时空变化特征研究对于评估冰川能量物质平衡及认识冰川消融过程至关重要。本文基于高空间分辨率的Landsat OLI影像和高时间分辨率的MOD10A1产品,并结合冰面反照率实测数据,开展了2011—2021年北疆萨吾尔山木斯岛冰川表面反照率的时空变化特征及其对冰川物质平衡影响的研究。结果表明:Landsat反演反照率和MOD10A1反照率与同期内冰面实测反照率的相关性分别为0.95和0.62,均显示木斯岛冰川表面反照率存在显著的时空变化特征;在空间尺度上,冰面反照率沿主流线整体随海拔升高呈增加趋势。但由于局部地形差异,反照率在海拔3 600 m以下区域随海拔升高出现下降趋势;在同一海拔处,反照率沿冰川两侧边缘向中部递增。2011—2021年,冰川年均反照率微弱增加,消融期内(5—8月)平均反照率与全年平均反照率的变化速率分别为0.0024 a-1和0.0017 a-1;逐月反照率具有显著的季节变化特征,6—8月冰面反照率较低(0.330),12月—次年2月冰面反照率较高(0.586);消融期内冰川消融区反照率下降幅度大于积累区。研究进一步表明,夏季(6—8月)平均反照率与冰川物质平衡存在显著的正相关(R=0.84,P<0.01),气温、固态降水、云量、太阳入射角、吸光性杂质等是影响冰川反照率变化的重要因素。该研究将对冰川消融过程和机理、能量物质平衡模拟等工作提供重要的基础支撑。     

天山乌鲁木齐河源1号冰川东支能量-物质平衡模拟研究

基于天山乌鲁木齐河源1号冰川东支海拔4 025 m处自动气象站的观测数据和同期物质平衡花杆观测数据,采用COSIMA模型,对该冰川东支2018年消融期单点能量-物质平衡进行了模拟。结果显示：物质平衡模拟值为（-0.67±0.03）m w.e.,与实测值有非常好的一致性,相关系数达0.96。造成冰川消融的能量来源于净短波辐射（84%）、感热通量（16%）;冰川能量支出为净长波辐射（55%）、冰川消融耗热（32%）、潜热交换（7%）及地热通量（6%）。受能量收支影响,模拟物质平衡主要取决于表面消融和固态降水。与我国其他区域大陆型冰川研究结果比较发现,乌鲁木齐河源1号冰川物质损失较为显著,能量通量主要取决于海拔以及气候条件,再冻结和固态降水显著小于羌塘1号冰川和扎当冰川,推测与单条冰川所处的大气环流有关。     

祁连山区雪冰反照率变化及其对冰川物质平衡的影响

雪冰反照率能够改变冰川表面能量收支平衡,是影响冰川消融的重要因素之一。利用祁连山地区冰川面积矢量数据、MODIS逐日积雪反照率、气温和降水以及冰川物质平衡等数据,探讨了祁连山典型冰川区雪冰反照率特征及其对冰川物质平衡的影响。结果表明：祁连山地区冰川多年平均反照率为0.532,冰川区面积大小与其多年平均反照率之间呈显著正相关（R²=0.16,P<0.05,N=91）,即冰川面积缩减1 km²,对应的平均反照率下降0.0025。祁连山老虎沟12号冰川反照率在夏季有明显的海拔效应,且强于其他时段,达到0.047?（100m）^-1。典型冰川年均物质平衡量与冰川表面夏季（6—8月）平均反照率之间存在显著的正相关关系,老虎沟12号冰川和七一冰川决定系数R²分别达到了0.48（P<0.05）和0.66（P <0.05）。冰川表面夏季平均反照率这一指标能够较好地衡量青藏高原北部祁连山地区冰川物质平衡的变化。     

Changes of the Hailuogou Glacier, Mt. Gongga,China, against the Background of Global Warming in the Last Several Decades

Great change, associated with global warming, has occurred at the Hailuogou (海螺沟)has retreated 1 822 m in the past 106 years, with an annual mean retreat of 17.2 m, and the front elevation has risen by 300 m since 1823. Comparison of glacier variations and temperature fluctuations in China and the Northern Hemisphere, over the last 100 years, indicates that glacier retreat stages occurred during the warm phase, and vice versa. Mass balance records during 1959/60--2003/04 have shown that the glacier has suffered a constant mass loss of snow and ice. The accumulated mass balance, -10.83 m water equivalent, indicates an annual mean value of -0.24 m water equivalent. The correlation between the mass balance and temperature is significant, which also indicates that climate warming is the crucial cause of glacier loss.Local hydrological and climatic data demonstrate that runoff from the glacier has been increasing both seasonally and annually.The correlation analysis and trend analysis indicate that ice and snow melted water is the main cause of an increase in the runoff. As the climate has become warmer, changes in the glacier surface morphology have obviously occurred. These include a decrease in glacier thickness, enlargement of glacial caves, and reduction of the size of clefts on the glacier surface. The ablation period has lengthened and the ablation area has expanded. A variety of factors thus provide evidence that the Hailuogou glacier has suffered a rapid loss of snow and ice as a result of climatic warming.     

挪威山地冰川上雪和粒雪中δ18O的解释及对区域气候的指示意义

Variations of δ18O in the snow which accumulates at a Nordic temperate glacier during the win-ter are not entirely eliminated after a few months of ablation in the following summer. Survive of isotopicsignals closely relates to the re-freezing capacity of snow accumulated in winter when its temperature wasbelow 0 ℃. The melt-water re-freezing ice layers formed in winter hindered subsequent melt-water percolation in summer when snow temperature was at melting point and, therefore, varied isotopic record wasreserved between these ice layers. The isotopic record in snow pack can provide an estimate of the ap-proximate trend of the most recent winter season temperatures. The relationship between regional tem-perature changes and δ18O values in the snow pack is affected by many natural factors, but 1989-1990 (aglacier balance year) winter air temperatures were reflected in the snow which remained on the glacierAustre Okstindbreen at an altitude of 1 350 m in July 1990. There was larger amplitude of variations ofδ18O values in the 4. 1 m of snow above the 1989 summer surface, but variations in the underlying firnwere relatively small. Melt water percolation modifies the initial variations of δ18O values in the snowpack. At a site below the mean equilibrium line altitude on Austre Okstindbreen, increased isotopic bom-ogenization within a ten-day period in July accompanied an increase of the mean δ18O value. Although theisotopic record at a temperate glacier is likely to be influenced by more factors than is that at polar glac-iers, it can provide an estimate of the approximate trend of recent local temperature variations.     

祁连山七-冰川反照率的参数化研究

通过对2006年和2007年暖季消融期七一冰川反照率的观测资料分析,基于冰川反照率的变化规律及其影响因素,根据实测资料的统计建模和验证,初步给出了具有试验基础的冰川反照率多因子参数化公式,其时间分辨率为1 h.经检验,2006年和2007年考察期间冰川反照率的模拟值和观测值序列之间的相关系数分别达到了0.901和0.9...     

天山南坡科其卡尔巴契冰川度日因子变化特征研究

度日模型是估算冰川消融的一种简单而有效的方法.根据科其卡尔巴契冰川2003年的观测资料,分析了该冰川度日因子的空间变化规律及其影响因素.研究表明:各高度上的度日因子,介于2.0～9.7mm·℃^-1·d^-1之间变化,平均值为5.7mm·℃^-1·d^-1,与青藏高原各冰川及其它地区冰川相比较小;随着海拔的增高,度日因子随之递增;随平均气温的升高而随之递减.由于冰面状况复杂,度日因子变化幅度较大,裸冰区的度日因子明显大于表碛覆盖区.人为测量误差、反照率、地形等对度日因子的影响也不容忽视.