北极斯瓦尔巴、高亚洲和阿尔卑斯山冰川物质平衡对比研究     

何海迪  李忠勤  叶万花  梁鹏斌  牟建新  张明军 《冰川冻土》2018,40(2):205-213

基于冰川物质平衡和平衡线高度数据,对北极斯瓦尔巴、高亚洲和阿尔卑斯山的冰川物质平衡变化和平衡线高度空间分布特征进行了对比分析,得出以下结论：（1）阿尔卑斯山冰川年均负物质平衡值最大,为-907 mm;斯瓦尔巴为-431 mm;高亚洲最小,为-264 mm。（2）高亚洲和斯瓦尔巴冰川物质平衡年振幅较小,年际变化较小;阿尔卑斯山冰川物质平衡年振幅较大,年际变化较大。斯瓦尔巴冰川物质平衡趋向正平衡,阿尔卑斯山和高亚洲冰川物质平衡趋向负平衡。（3）斯瓦尔巴内陆的冰川平衡线高度高于沿海地区,高亚洲冰川平衡线高度呈纬向地带性、经向地带性和区域地带性的分布规律,阿尔卑斯山的冰川平衡线高度主要受冰川所处海拔的影响。  相似文献   

开敞式潮滩-潮沟系统发育演变动力机制——Ⅲ.海平面上升影响          下载免费PDF全文

龚政  严佳伟  耿亮  朱思谕  李欢  张长宽 《水科学进展》2018,29(1):109-117

为研究海平面上升对潮滩-潮沟系统的影响,以江苏中部粉砂淤泥质海岸为原型,建立变态物理模型,模拟研究在不同海平面潮汐过程作用下的潮沟发育和演变过程,分析了潮滩淹没历时、排水密度、潮沟断面形态等特征参数变化规律。研究表明:潮沟在发育初期伸长速率高于拓宽速率,最终趋于动态平衡;海平面上升后,潮滩淹没历时增加,露滩时间缩短,归槽水对潮沟底床的塑造作用减弱;平均归槽水流长度和Horton排水长度均随海平面上升呈现出减小趋势,潮沟的排水能力增强;潮沟断面宽深比服从对数正态分布,随着海平面上升,潮沟断面面积和宽深比均呈现出增大趋势,宽深比分布范围变广。  相似文献   

Measuring household vulnerability to climate change—Why markets matter     

Sofie Skjeflo 《Global Environmental Change》2013,23(6):1694-1701

Climate change and climate variability affect households in developing countries both directly through their impact on crop yields and indirectly through their impact on wages, food prices and the livelihoods of the poor. Therefore, vulnerable household groups cannot be identified without considering their position in and access to markets. I illustrate the effects – transmitted through markets – that are significant in household exposure, sensitivity and adaptive capacity to climate change by simulating productivity shocks to maize up to 2030 due to climate change in a computable general equilibrium model of Malawi. The results show that rural households with large land holdings may benefit from the adverse impact of climate change on maize yields as a result of increased maize prices. Urban poor and small-scale farmers are vulnerable to climate change due to the large portion of their incomes spent on food. Existing vulnerability measures that do not consider equilibrium effects and characterise all farmers as vulnerable may therefore be misleading.  相似文献   

Static bay beach concept for scientists and engineers: A review     

John R.-C. Hsu  M.-J. Yu  F.-C. Lee  Lindino Benedet 《Coastal Engineering》2010

Headland-bay beach (HBB) is one of the most prominent physiographic features on the oceanic margin of many countries in the world. Under the influence of a predominant swell, its curved periphery in natural environment may reach static equilibrium and remains stable without sediment supply from updrift and/or a riverain source within its own embayment. Coastal scientists and engineers have attempted to develop mathematical expressions to quantify this ideal bay shape since the 1940s. As the scenario with depleting sediment supply has become a common reality on many parts of the world coastline in more recent time, some coastal engineers have advocated a rational approach to mimicking the static bay shape found in nature in order to mitigate beach erosion as well as for coastal management. Nowadays, many useful applications have emerged since the publication of the parabolic bay shape equation (PBSE) developed for static equilibrium planform (SEP) in late 1980s. The advance in modern computer technologies and international collaboration has further facilitated the exchange of knowledge and applications of this static bay beach concept (SBBC).  相似文献   

Cu₃ N弹性和热力学性质的第一性原理研究     

李世娜  刘永 《海洋学报》2010,32(10):6882-6888

利用基于密度泛函理论的第一性原理全势线性缀加平面波方法,研究了立方反ReO₃结构Cu₃N在零温(0 K)零压下的平衡晶格常数、体弹模量及其对压强的一阶导数,计算结果与其他实验及理论结果基本相符. 同时得出Cu₃N的弹性常数,Poisson比等,并分析出Cu₃N在零温零压下是稳定的. 通过准谐Debye模型计算Cu₃N的热力学性质,得到了Cu₃N的晶格常数、等压比热容、等容比热  相似文献   

Annual heat balance and equilibrium temperature of Lake Aegeri,Switzerland   总被引：1，自引：0，他引：1  

David M. Livingstone  Dieter M. Imboden 《Aquatic Sciences - Research Across Boundaries》1989,51(4):351-369

The mean heat budget of Lake Aegeri, Switzerland, is 950 MJ·m^–2, comparable to that of neighbouring lakes. The annual variation in the net heat flux can be adequately described using a six-term heat balance equation based on 12 years of monthly mean meteorological and surface temperature data. Although the magnitude of the net heat flux is dominated by the radiative terms of the equation, the one-month backward shift of the net flux and total heat content extrema from the solstices and equinoxes respectively is due to the phase shift of the non-radiative with respect to the radiative terms. A linear approximation was used to express the net heat flux in terms of a heat exchange coefficient and an equilibrium temperature. The former varies from 17 to 28 W·m^–2·K^–1 in the course of a year; fluctuations in the latter are found to depend mainly on fluctuations in cloud cover and relative humidity, whilst the effect of fluctuations in air temperature and wind speed is slight.  相似文献   

利用原生岩浆定量反演原岩微量元素丰度的方法   总被引：1，自引：0，他引：1  

杨晓松 《岩石矿物学杂志》1994,13(1):33-41

利用同源不同程度平衡部分熔融作用形成的两种原生岩浆岩的微量元素浓度，提出了一种定量反演原岩微量元素丰度的方法。反演前不需要做任何人为假设，为定量研究源区的微量元素地球化学提供了一个有力的手段。对汉诺坝新生代橄榄拉斑玄武岩和碱性玄武岩的成因及地幔源区特征作了讨论。反演结果显示本区地幔相对球粒陨石有过明显的ＲＥＥ富集过程，并且不同的ＲＥＥ富集程度存在显著的差异。  相似文献   

3-D density model for the lithosphere of Europe: construction method and preliminary results   总被引：1，自引：0，他引：1  

T. P. Yegorova  V. G. Kozlenko  N. I. Pavlenkova  V. I. Starostenko 《Geophysical Journal International》1995,121(3):873-892

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H~+,Li~+,Mg~(2+)∥Cl~-—H_2O四元水盐体系在-10℃时的平衡溶解度相图     

王继顺  高世扬  刘铸唐  王波 《盐湖研究》1993,(2)

本文利用等温溶解度法测定了H~+,Li~+,Mg~(2+)//Cl~-—H_2O四元水盐体系在—10℃±0.1℃时的溶解度并绘制了等温相图。相图由HCl·MgCl_2·7H_2O、MgCl_2·8H_2O、HCl·6H_2O和LiCl·2H_2O四个相区构成,只有一个零变量点I:LiCl·2H_2O+MgCl_2·6H_2O+HCl·MgCl_2·7H_2O+L_(?)利用坐标变换和直线外推法,对溶解度数据进行处理后,用湿渣结线法解决了低温平衡固相较难确定的问题。  相似文献   

三元体系Li~+,Mg~(2+)∥SO_4~(2-)—H_2O 25℃相关系及溶液物化性质的研究          下载免费PDF全文

李冰  房春晖  王庆忠  李军  宋彭生 《盐湖研究》1993,(3)

研究了三元体系Li~+,Mg~(2+)∥SO_4~(2-)—H_2O在25℃时的相关系和平衡液相的密度、粘度、折光率、电导等物化性质,该体系为简单共饱型,两段溶解度曲线对应于体系的两种原始组份Li_2SO_4·H_2O和MgSO_4·7H_2O的结晶区,无复盐和固溶体形成,亦无脱水作用发生,应用电解质溶液Pitzer模型检测该体系25C的溶解度,并用经验或半经验公式对平衡液相的密度和折光率进行了理论计算,计算值与实验值非常接近。  相似文献