乌鲁木齐河源1号冰川雪-冰界面含氮离子迁移研究

冰川积累区雪-冰界面附近的化学物质迁移对冰芯记录的形成具有重要意义,为讨论主要含氮离子在这一界面的迁移,本研究基于2004年11月至2006年3月在天山乌鲁木齐河源1号冰川连续采集的64组雪冰样品分析了NO3-与NH4+的变化情况。结果表明,雪层底部干季(11月至翌年3月)含氮离子浓度的平均值高于湿季(4—10月)的,而冰层顶部离子浓度的平均值则相反,即干季的低于湿季的,雪-冰界面附近5cm与15cm尺度上均有体现;干季的离子浓度雪冰比(雪层底部与冰层顶部含氮离子浓度的比值)平均值大于湿季的,即干季雪层底部含氮离子的浓度一般高于冰层顶部的浓度,湿季其表现出相反的趋势;雪-冰界面附近含氮离子的迁移反映了环境信息的记录过程,受到融水和气温变化等因素的综合影响。

乌鲁木齐河源1号冰川雪-冰界面化学离子的迁移研究

为讨论主要化学离子在雪-冰界面的迁移,对采自乌鲁木齐河源1号冰川海拔4130m处的73组连续雪冰样品中8种主要化学离子的浓度变化进行了分析。结果表明:尽管不同离子浓度变化存在一定差异,但总体而言,雪层底部干季(11月至次年3月)8种主要化学离子浓度平均值高于湿季(4月~10月),而冰层顶部8种主要化学离子浓度平均值干季低于湿季;干季主要离子浓度的雪冰比平均值大于湿季,湿季恰好相反,雪层底部各离子的浓度均低于冰层顶部的浓度;雪-冰两种界面上主要化学离子的迁移反映了冰芯记录被保存的过程,受到离子活性、物源、融水、气温变化等多因素的综合影响。

拉萨和日喀则地区雪-冰表面吸光性物质特征及其影响因子分析

雪-冰表面吸光性物质可加速冰川消融。研究了拉萨和日喀则地区雪-冰表面吸光性物质(黑碳(BC)和有机碳(OC))的分布特征、污染来源及其影响因子。结果表明:研究区域内雪-冰中BC和OC的质量浓度分别为5~157、26~243 ng/g,平均质量浓度分别为48、97 ng/g;日喀则地区的BC和OC的质量浓度分别为(25±16)、(62±28)ng/g;拉萨地区的BC和OC的质量浓度分别为(71±43)、(132±62)ng/g。通过对吸光性物质的影响因子分析发现:冬春季节,南亚和中亚等地区的污染物随气流的远距离传输对研究区域的污染贡献较大;吸光性物质随海拔升高呈现出递减趋势;不同土地利用类型中BC含量大小分布依次为:郊区用地>建设用地>农田用地>牧区用地,OC含量大小分布依次为:郊区用地>农田用地>建设用地>牧区用地。

“冰雪聪明”的文学史意义——从苏雪林与冰心的早期散文比较看“美文运动”中的女性写作

20世纪20年代"冰雪聪明"的存在构成了对以男性作家为主要代表的美文运动的冲击。苏雪林与冰心以其不同的"闺阁"写作,在主题内容、文体风格及为文为人等方面显示出女性写作对美文运动的特殊影响。

第3讲 海冰热力学

介绍了主要的海冰热力学过程,包括:海冰表面状况和反照率;冰内辐射传输;雪/冰表面热平衡和冰内热力学过程等。

青藏高原中汞的分布特征及影响因素——以典型海洋性冰川小流域为例

本研究以青藏高原典型海洋性冰川的雪冰-径流水为研究对象,分析讨论了雪冰-径流水中汞浓度变化趋势及控制因素.结果表明,贡嘎山冰川中雪、冰样品的THg浓度略高于全球背景值,而明永冰川以及米堆冰川的雪、冰、水样品均处于全球背景水平.3个冰川所有雪样、冰样、水样的THg浓度平均值分别为(4.78±5.99)ng/L、(1.72±1.15)ng/L、(1.31±0.91)ng/L.不同的环境介质中THg浓度变化总体表现为:雪>冰>水,其主要受颗粒汞沉淀作用及气态单质Hg挥发作用的控制.贡嘎山的径流水中THg浓度表现为六月最高(7.48±2.22)ng/L,十一月最低(1.39±0.27)ng/L.所有雪冰-径流水体系中HgP与THg存在极显著的正相关关系,雪中HgP/THg最高,其次为冰,最低为径流水.贡嘎山径流水中的HgP/THg及月均THg输出变化趋势受径流量和降雨量的影响.主成分分析表明了本研究区域雪冰中THg浓度主要受大气颗粒物沉降及季风传输的影响.此外,相比于其他2个冰川,贡嘎山冰川由于更加靠近人类活动密集区域,更易受到人类活动的影响.

Impact of ice-snow damage on nutrient distribution of a Cunninghamia lanceolata woodland

During January to February in 2008,severe ice-snows occurred on 2.09×10^6 km^2 of south China and caused tremendous damage to the forests.Stem damage and crown debris input from the ice-snow in a Cunninghamia lanceolata stand in northern Guangdong Province,China,were investigated to determine the extent of ice-snow damage to trees and the nutrient distribution characteristics on woodland.Icicles were produced on branches and leaves of the C.lanceolata trees by sleets,resulting in all live trees were damaged by stem breakage.A strong positive correlation was found between the broken position of trees and diameter at breast height（DBH）.Nutrient concentrations varied according to components of crown debris.Total nutrient concentration graded in the following order：leaves 〉stembark 〉branches 〉stemwood.Crown debris input from ice-snows was 19.11 t·ha^-2,and branches,stemwood,leaves and stembark accounted for 37%,28%,27% and 8%,respectively.Nutrient distributions between components of crown debris differed drastically in 2008.The contribution of leaves to total nutrient accumulation of crown debris was 70%,whereas branches,stemwood and stembark contributed 13%,7% and 10%,respectively.Accumulations of N,P and K by the woodland were 105 067.9 t·ha^-2 in 2008,and the nutrients of crown debris,litter and the stand soil accounted for 0.18%,0.03% and 99.79%,respectively.The order of nutrient accumulation in leaves,branches,stembark,stemwood of crown debris and litter was N〉K〉P,but the nutrients stored in the soil were in the order of K 〉N 〉P.The N and P concentrations of litter in 2009 were greater than those in 2008,whereas its K concentration was smaller than that of the latter.N and P concentrations of stemwood and stembark in 2009 were slightly greater than those in 2009,whereas their K concentration was smaller than the latter.The N and P accumulations of stemwood and stembark of crown debris in 2009 were close to those in 2008,whereas their K accumulation was slightly smaller than the latter.The N,P and K accumulations of litter in 2009 was greater than those in 2008.

Support Vector Machines for Cloud Detection over Ice-Snow Areas

In polar regions, cloud and underlying ice-snow areas are difficult to distinguish in satellite images because of their high albedo in the visible band and low surface temperature of ice-snow areas in the infrared band. A cloud detection method over ice-snow covered areas in Antarctica is presented. On account of different texture features of cloud and ice-snow areas, five texture features are extracted based on GLCM. Nonlinear SVM is then used to obtain the optimal classification hyperplane from training data. The experiment results indicate that this algorithm performs well in cloud detection in Antarctica, especially for thin cirrus detection. Furthermore, when images are resampled to a quarter or 1/16 of the full size, cloud percentages are still at the same level, while the processing time decreases exponentially.

Scattering of Surface Waves by the Edge of a Small Undulation on a Porous Bed in an Ocean with Ice-cover

Scattering of surface waves by the edge of a small undulation on a porous bed in an ocean of finite depth, where the free surface has an ice-cover being modelled as an elastic plate of very small thickness, is investigated within the framework of linearized water wave theory. The effect of surface tension at the surface below the ice-cover is neglected. There exists only one wave number propagating at just below the ice-cover. A perturbation analysis is employed to solve the boundary value problem governed by Laplace＇s equation by a method based on Green＇s integral theorem with the introduction of appropriate Green＇s function and thereby evaluating the reflection and transmission coefficients approximately up to first order. A patch of sinusoidal ripples is considered as an example and the related coefficients are determined.

Evaluation of the HadISST1 and NSIDC 1850 onward sea ice datasets with a focus on the Barents-Kara seas

In recent years,long-term continuous sea-ice datasets have been developed,and they cover the periods before and after the satellite era.How these datasets differ from one another before the satellite era,and whether one is more reliable than the other,is important but unclear because the sea-ice record before 1979 is sparse and not continuous.In this letter,two sets of sea-ice datasets are evaluated:one is the HadISST1 dataset from the Hadley Centre,and the other is the SIBT1850(Gridded Monthly Sea Ice Extent and Concentration,from 1850 Onward)dataset from the National Snow and Ice Data Center(NSIDC).In view of its substantial importance for climate,the winter sea ice in the Barents and Kara seas(BKS)is of particular focus.A reconstructed BKS sea-ice extent(SIE)is developed using linear regression from the mean of observed surface air temperature at two adjacent islands,Novaya Zemlya and Franz Josef Land(proxy).One validation illustrates that the proxy is substantially coherent with the BKS sea-ice anomaly in the observations and the CMIP5(phase 5 of the Coupled Model Intercomparison Project)historical experiments.This result indicates that the proxy is reasonable.Therefore,the establishment of the reconstructed BKS SIE is also reasonable.The evaluation results based on the proxy suggest that the sea-ice concentration prior to the satellite era in the NSIDC dataset is more realistic and reliable than that in the Hadley Centre dataset,and thus is more appropriate for use.

Investigation of Correlation between the Temperature on Air-Snow and Snow-Ice Interfaces and the Atmospheric Air Temperature

Solution of the practical problems of the ice engineering requires the data about the strength of the ice cover that depends upon its temperature. In most cases, the snow lies on the ice cover and the ice temperature differs from the atmospheric air temperature. To reveal the correlation of the air temperature with temperature on interfaces air-snow and snow-ice, the known in the thermophysics solution of the problem of the heat transfer through the multilayer plate was applied. Derived solution connects the temperature of air and temperature on the snow-ice interface and satisfactory correlates with data of the field measurements of the temperature within snow layer and ice cover and ice thickness on the Heilongjiang （Amur） River. Results of investigation are recommended for the ice temperature evaluation in engineering practice.

物理-化学综合融雪除冰沥青混合料研究

为将橡胶颗粒沥青混合料除冰技术与盐化物融雪沥青混合料除冰技术相结合,旨在研究一种新型的环保型物理-化学融雪除冰沥青混合料。本文分别就盐化物融雪剂的选择、橡胶颗粒的掺入方法、物理-化学融雪除冰沥青混合料配合比设计、物理-化学融雪除冰沥青混合料的成型工艺等4个方面进行了深入研究,评价了PCAM-13的融雪除冰性能,为解决冬季道路冰雪问题提供了新的思路和途径。

Ice melting performance of deicers and their effect on stripping resistance of asphalt mixture

The ice melting performance of three types of deicers, including sodium chloride, calcium chloride and sodium acetate, were tested in laboratory under different temperature conditions, and their effects on asphalt mixture were evaluated from the point of the stripping resistance of asphalt mixture. Unsaturated Marshall samples were exposed to freeze-thaw cycling while immersed in the deicer solutions of different concentrations. After the freeze-thaw cycles, Cantabro tests were performed, and Cantabro loss was adopted to characterize the stripping resistance of asphalt mixture. The test results show that calcium chloride has the best comprehensive ice melting performance, and all deicers have detrimental effect on the stripping resistance of asphalt mixture at different degrees. The damage degree depends on deicer types and their concentration in the solution. Deicer solutions with about 2% concentration cause the greatest loss of stripping resistance due to serious freeze-thaw damage. Sodium acetate causes greater loss of stripping resistance than sodium chloride and calcium chloride at the same concentration.

Research on asphalt concrete pavement deicing technology

In order to reduce the cohesive force between pavement and ice, the approach of pavement surface coating with hydrophobic admixtures is investigated. The deicing effect of this approach is examined by the contact angle test and the shear test. The durability of the approach is examined by the accelerated abrasion test, and the skid resistance of the pavement with surface coating is examined by the British pendulum test and the surface texture depth test. In the contact angle test, the contact angle between hydrophobic admixture and water is 100.2°. In the shear test, the maximum shear stress is 0.06 MPa for the specimen coated with hydrophobic admixture, which is much lower than that of the specimen without hydrophobic admixture coating, 3.5 MPa. Furth- ermore, the ice and asphalt surface are completely separated for the coated specimen while not for the uncoated specimen. Based on the accelerated abrasion test, the residual hydro- phobic admixture in the veins of the pavement after abrasion still has a deicing effect. From the skid resistance tests, the British pendulum number （BPN） and the texture depth （TD） of the specimen coated with hydrophobic admixtures are larger than those of the standard requirements. The overall experi-mental observation indicates that the approach can effectively reduce close contact between asphalt pavement and ice; therefore, it can be a promising solution to road icing problems in winter.

The Variability of the Snow and Ice Melt in Alpine Rivers in Northwestern China

The study of snow and ice melt （SIM） is important in water-scarce arid regions for the assessment of water supply and quality. These studies involve unique difficulties, especially in the calibration of hydro-models because there is no direct way to continuously measure the SIM at hydrostations. The recursive digital filter （RDF） and the isotopic hydro-geochemical method （IHM） were coupled to separate the SIM from eight observed series of alpine streamflows in northwestern China. Validation of the calibrated methods suggested a good capture of the SIM characteristics with fair accuracy in both space and time. Applications of the coupled methods in the upper reaches of the Hei River Basin （HRB） suggested a double peak curve of the SIM fraction to streamflow for the multi-component recharged （MCR） rivers, while a single peak curve was suggested for the rainfall-dominant recharged （RDR） rivers. Given inter-annual statistics of the separation, both types of the alpine rivers have experienced an obvious decrease of SIM since 196os. In the past 10 years, the SIM in the two types of rivers has risen to the levels of the 1970s, but has remained lower than the level of the 1960s. The study provided a considerable evidence to quantify the alpine SIMbased on the separation of observed data series at gauge stations. Application of the coupled method could be helpful in the calibration and validation of SIM-related hydro-models in alpine regions.

Deposition of atmospheric pollutant and their chemical characterization in snow pit profile at Dokriani Glacier,Central Himalaya

The uncertainty in assessing the numerous atmospheric pollutants transported via wind from arid and semi-arid regions is affecting the glacial ecosystem. In our study area due to the complexity of the system, a prominent seasonal difference noticed among major ions(Ca^(2+), Mg^(2+), SO_4^(2-), and NO_3^-). There is a need for understanding the ions cycling as a whole and the directionality of the feedback loops in the system. Therefore, we provide an appraisal of our current hypothesis for seasonal difference in major ion concentration from snow samples for two corresponding years(2013 and 2015) at Dokriani Glacier. A systematic study of chemical compositionsin the shallow snow pit from Dokriani Glacier was undertaken for the pre-monsoon season to understand the cycling of major ions from atmosphere to solute acquisition process. The intimating connections of ions cycling in snow and its temporal behavior was observed and analyzed through various statistical tests. Among major ions, the SO_4^(2-)has the highest concentration among anions on an average considered as 14.21% in 2013 and 29.46% in 2015. On the other side Ca^(2+) is the dominant cation contributing 28.22% in 2013 and 15.3% in 2015 on average. The average ratio of Na+/Cl-was higher in 2013 whereas lower in 2015. The backward trajectory analysis suggests the possible sources of the ions transported from Central Asia through the Western Disturbance(WD) as a prominent source of winter precipitation mainly in the Central Himalaya. Ionicconcentration of Ca^(2+) in cations was highly dominated while in anion SO_4^(2-)played the major role. Factor analysis and correlation matrix suggested that, the precipitation chemistry is mostly influenced by anthropogenic, crustal, and sea salt sources over the studied region. The elemental cycling through ocean, atmosphere and biosphere opens up new ways to understand the geochemical processes operating at the glacierized catchments of the Himalaya. Moreover, increasing the field-based studies in the coming decades would also have the certain advantage in overcoming the conceptual and computational geochemical modelling difficulties.

Simulation of a Freezing Rain and Snow Storm Event over Southern China in January 2008 Using RIEMS 2.0

The Regional Integrated Environmental Model System （RIEMS 2.0） with NCEP Reanalysis II is utilized to simulate the severe freezing rain and snow storm event over southern China in January 2008, which caused severe damage in the region. The relationships between the freezing rain process and the large-scale cir- culation, in terms of the westerly and low-level jets, water vapor transportation, and northerly wind area/intensity indices, were analyzed to tmderstand the mechanisms of the freezing rain occurrence. The results indicate the fol- lowing： （1） RIEMS 2.0 reproduced the pattern of precipi- tation in January 2008 well, especially for the temporal evolution of daily precipitation averaged over the Yangtze River valley and southern China; （2） RIEMS 2.0 repro- duced the persistent trough in the South Branch of the westerlies, of which the southwesterly currents trans- ported abundant moisture into southern China; （3） RIEMS 2.0 reasonably reproduced the pattern of frequencies of light and moderate rain, although it overestimated the frequency of rain in southern China. This study shows that RIEMS 2.0 can be feasibly applied to study extreme weather and climate events in East Asia.

Effects of spring Arctic sea ice on summer drought in the middle and high latitudes of Asia

Based on data observed from 1979 to 2017,the influence of Arctic sea ice in the previous spring on the first mode of interannual variation in summer drought in the middle and high latitudes of Asia(MHA)is analyzed in this paper,and the possible associated physical mechanism is discussed.The results show that when there is more sea ice near the Svalbard Islands in spring while the sea ice in the Barents-Kara Sea decreases,the drought distribution in the MHA shows a north-south dipole pattern in late summer,and drought weakens in the northern MHA region and strengthens in the southern MHA region.By analyzing the main physical process affecting these changes,the change in sea ice in spring is found to lead to the Polar-Eurasian teleconnection pattern,resulting in more precipitation,thicker snow depths,higher temperatures,and higher soil moisture in the northern MHA region in spring and less precipitation,smaller snow depths,and lower soil moisture in the southern MHA region.Such soil conditions last until summer,affect summer precipitation and temperature conditions through soil moisture–atmosphere feedbacks,and ultimately modulate changes in summer drought in the MHA.

NO_x Release from Snow and Ice Covered Surface in Polar Regions and the Tibetan Plateau

The exchanges of NOx between snow and air have significant impact on the atmospheric components and photochemical processes in the overlying boundary layer. Such exchanges increase the oxidizing capacity of the atmosphere and may have a crucial impact on the air signals that are retrieved from ice cores. In the recent years, sunlit snow and ice have been demonstrated to be important NOx sources in the polar atmospheric boundary layer. This paper makes a thorough review on the release of NOx from snow and ice, including field observations and experimental evidences, release mechanisms and influential parameters that affect such a release process, polar NOx concentrations and fluxes, and environmental impacts of the chemical processes of NOx in the polar atmospheric boundary layer. In the Tibetan Plateau, the released NOx observed recently in the sunlit snow/ice-cover is 1-order magnitude more than that in polar regions, but further scientific research is still needed to reveal its impact on the atmospheric oxidizing capacity.

High-quality Development Paths of Ice-snow Tourism in China from the Perspective of the Winter Olympics

Preparations for the Beijing Winter Olympics have promoted the rapid development of ice-snow tourism in China,which contributes to achieving the goal of having“300 million people participate in ice-snow sports”.This paper analyzes the status quo and problems associated with the growth of ice-snow tourism in China based on the methods of documentation and field investigation.The results indicate that China’s efforts have born abundant fruits.Notwithstanding,there are still some problems due to the limited time and hastened process of ice-snow tourism development,including unreasonable exploitation,low-quality products and services,imperfect investment and financing system,inadequate management,a single marketing mode,and insufficient talent teams.Compared with developed countries in Europe and the United States,ice-snow tourism in China is in the stage of rapid development.To achieve the high-quality development of ice-snow tourism in China,this paper proposes actions from eight aspects which involve policy,products and services,marketing,safety management and control,talent teams,standardization construction,science and technology,and community participation.This study can provide references for the high-quality development of ice-snow tourism in China,as well as perfecting Chinese theoretical research on ice-snow tourism.