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排序方式: 共有489条查询结果,搜索用时 15 毫秒
101.
The seasonal and inter-annual variations of pH and EC(electrical conductivity) at Yu-long(玉龙) Snow Mountain,Lijiang(丽江) City,are sensitive to precipitation variations and are important indicators of the atmospheric environment.The pH of summer rainfall at Lijiang City ranges from 6.7 to 7.4,and alkaline mineral salts dominate the variations of rainfall acidity.pH values in theshallow firn profile at Baishui(白水) Glacier No.1 range from 5.6 to 6.3,and EC values from 2.4 to 7.3 μs/cm.The ranges are lower than ... 相似文献
102.
贡嘎山海螺沟冰川物质平衡、水交换特征及其对径流的影响 总被引:12,自引:17,他引:12
在贡嗄山海螺沟冰川研究的基础上,提出计算该冰川物质平衡的两种方法,获得了较一致的结果,表明近10a来物质平衡平均为-470mm,与高亚洲边缘山脉的冰种同样处于强烈的衰退状态,该冰川有很高的物质平衡水平(2544mm)及水交换水平(3819mm),液相比例高(1/3),较小的稳定性系数(0.20),具有典型的季风海洋型冰川的水交换特征,由于冰川退缩冰川径流增加,预计2020年将达到临界状态,在气候持续暖变湿情况下,预测临界状态将延至2050年左右,冰川面积及储量将大幅度减少小。 相似文献
103.
东南极Lambert冰川流域路线考察 总被引:3,自引:1,他引:3
Lambert冰川是Amery冰架的补给源,为东南极冰盖最大的一支冰流。近几年对该冰流源区的路线考察表明,该地区累速度相当低,大部分观测点你于150kg/(m^2.a)。考察区域表面年平均温度为-45--30℃。表面2m雪层的平均密度在400kg/m^3左右变化,在1830-2700m海拔范围内的许多地点曾观测到深霜发育,表面运动速度基本上在20m/a以内。在低积累区,强烈的下降风和表面雪丘的发育 相似文献
104.
Turbulence measurements performed in a stable boundary layer over the sloping ice surface of the Vatnajökull in Iceland are described. The boundary layer, in which katabatic forces are stronger than the large-scale forces, has a structure that closely resembles that of a stable boundary layer overlying a flat land surface, although there are some important differences. In order to compare the two situations the set-up of the instruments on an ice cap in Iceland was reproduced on a flat grass surface at Cabauw, the Netherlands. Wind speed and temperature gradients were calculated and combined with flux measurements made with a sonic anemometer in order to obtain the local stability functions m and h as a function of the local stability parameter z/L. Unlike the situation at Cabauw, where m was linear as a function of z/L, in the katabatically forced boundary layer, the dependence of m on stability was found to be non-linear and related to the height of the wind maximum. Thermal stratification and the depth of the stable boundary layer however seem to be rather similar under these two different forcing conditions.Furthermore, measurements on the ice were used to construct the energy balance. These showed good agreement between observed melt and components contributing to the energy balance: net radiation (supplying 55% of the energy), sensible heat flux (30%) and latent heat flux (15%).Local sources and sinks in the turbulent kinetic energy budget are summed and indicate a reasonable balance in near-neutral conditions but not in more stable situations. The standard deviation of the velocity fluctuations u, v, and w, can be scaled satisfactorily with the local friction velocity u* and the standard deviation of the temperature fluctuation with the local temperature scale *. 相似文献
105.
青藏高原地区过去2000年来的气候变化 总被引:14,自引:0,他引:14
依据冰芯、树轮、沉积物分析和冰川波动等各单点古气候代用资料,以及重建的综合温度变化曲线,分析了近 2000年青藏高原温度变化的整体性和区域性特征。全青藏高原综合温度曲线显示中世纪暖期(1150-1400年)、小冰期(1400-1900年)以及公元 3~5世纪冷期的存在。青藏高原温度变化具有明显的区域性特征。在 9~11世纪,青藏高原东北部以温暖为特征,而青藏高原南部和西部表现为寒冷。青藏高原南部和西部分别于1150-1400年(此时段在高原东北部表现为弱暖期)和1250-1500年经历了气候变暖。与中国东部文献记录的最新综合研究结果比较,高原东北部与中国东部的温度变化最为一致。而且,许多重大气候事件,如1100-1150年、1500-1550年、1650-1700年和1800-1850年的冷事件在高原和中国东部同时出现,而后 3次冷期与小冰期期间中国西部发生的冰川前进相匹配。 相似文献
106.
Responses to climatic changes since the Little Ice Age on Maladeta Glacier (Central Pyrenees) 总被引:2,自引:0,他引:2
J. Chueca Cía A. Julin Andrs M.A. Saz Snchez J. Creus Novau J.I. Lpez Moreno 《Geomorphology》2005,68(3-4):167-182
The evolution of Maladeta Glacier (Maladeta massif, central Spanish Pyrenees) since the Little Ice Age maximum is analyzed in this work. The extent of the glacier was mapped into 10 stages using morainic deposits and graphic documents. Climatic data (temperature and precipitation) were reconstructed by using dendroclimatic techniques complemented by recent instrumental records. The results thus obtained confirm the control of the above mentioned climatic factors, particularly annual temperature and winter precipitation, in the evolution of Maladeta Glacier, which has receded from an extent of 152.3 ha in 1820–1830 to 54.5 ha in 2000, a 35.7% reduction in size. The rate of ice wastage has varied during that period, defining several phases of glacial stabilization (1820–1830 to 1857; 1914–1920 to 1934–1935; 1957 to 1981), moderated glacial depletion (1901–1904 to 1914–1920; 1934–1935 to 1957) and marked glacial depletion (1857 to 1901–1904; 1981 to 2000). The evolution of Maladeta Glacier is also in keeping with trends observed from other alpine Mediterranean glaciers, which have experienced a consistent rise in their equilibrium line altitudes during the 19th and 20th centuries as well as associated and prolonged periods of negative mass balance. 相似文献
107.
Surface Heat Balance and Spatially Distributed Ablation Modelling at Koryto Glacier, Kamchatka Peninsula, Russia 总被引:1,自引:0,他引:1
Keiko Konya Takane Matsumoto Renji Naruse 《Geografiska Annaler: Series A, Physical Geography》2004,86(4):337-348
To investigate the characteristics of ablation at Koryto Glacier, a mountain glacier under maritime climate in Kamchatka Peninsula, Russia, we made field observations from August to early September 2000. At a site near the equilibrium line, the 31‐day average net radiation, sensible heat flux, and latent heat flux were 43, 59 and 31 W?2, respectively. We developed a new distributed ablation model, which only needs measurements of air temperature and global radiation at one site. Hourly ablation rates at this site obtained by the energy balance method are related to measured air temperature and global radiation by linear multiple regression. A different set of multiple regression coefficients is fitted for snow and ice surfaces. Better estimates of ablation rate can be obtained by this approach than by other temperature index models. These equations are then applied to each grid cell of a digital elevation model to estimate spatially distributed hourly melt. Air temperature is extrapolated using a constant temperature lapse rate and global radiation is distributed considering topographic effects. The model enables us to calculate the hourly spatial distribution of ablation rates within the glacier area and could well provide a realistic simulation of ablation over the whole glacier. 相似文献
108.
109.
Ian S. Evans 《Geografiska Annaler: Series A, Physical Geography》2006,88(2):115-133
Mass balance of glaciers in mountain areas varies not only with altitude and regional position but also with aspect, gradient, glacier size, glacier type and detailed topographic position. These factors are combined here in models of how glacier altitude varies, tested with data for the Alps edited from the World Glacier Inventory. An overall northward tendency in glacier numbers (toward 005 ± 4°) and lower altitudes (013 ± 5°) is maintained across a range of glacier sizes, types, altitudes and the major divisions of the Alps. Variation with aspect of glacier altitude (and, by implication, of glacier balance) in the Alps is essentially unimodal, and north‐facing glaciers average 220 m lower in middle altitude than south‐facing: 148 m in the Western Alps, 232 m in the West‐central, 252 m in the East‐central, and 268 m in the Eastern Alps. For smaller subdivisions, confidence intervals on estimates are broader and many differences lack statistical significance. Contrasts are greater in the higher massifs, with greater relief, and lower in cloudy, windward areas. There are small windrelated tendencies east of north along the northern and western fringes, but trends across space are weak: position is thus treated by subdivision into districts and groups. Mid‐altitude averages 2891 m overall and varies from 2552 to 3127 m for 27 glacier districts, and from 2124 to 3209 m for 103 glacier groups. Glacier mid‐altitude varies also with glacier form, nourishment, height range and area, which account for over two‐thirds of variance in combined models. 相似文献
110.
希夏邦马峰抗物热冰川离子淋溶作用对冰芯记录的影响(英) 总被引:1,自引:1,他引:0
The ion elution process has a severe effects on the formation of ice core record, which is discussed on the results of ice core record from kangwure Glacier, Xixabangma Peak. 相似文献