晚三叠世以来龙门山的隆升—剥蚀过程研究——来自前陆盆地沉积通量的证据

本文根据钻井、地层剖面等资料,利用Surfer8.0软件编制出晚三叠世以来龙门山前陆盆地各构造层序的残留地层等厚图,计算出6个构造层序地层的沉积总量、沉积通量.沉积通量分别为:300.2g/(m2·ka)、66.5g/(m2·ka)、71.7 g/(m2 ·ka)、38.5 g/(m2·ka)、113.0 g/(m2·ka)、1204.6 g/(m2·ka).利用物质平衡法将各阶段沉积物回剥至物源区,计算各阶段物源区剥蚀速率分别为:167.3 mm/ka、22.5 mm/ka、22.9 mm/ka、9.8mm/ka、22.9 mm/ka、319.4 mm/ka.计算结果表明,晚三叠世以来,物源区的剥蚀速率和沉积区的沉积速率均具有先减小后增大的变化规律,晚三叠世和晚新生代是剥蚀一沉积过程最强烈的两个阶段,可能对应了龙门山强烈隆升的两个时期.根据对盆地沉积物总量的估算,利用物质平衡的原理,可以推算出龙门山自晚三叠世开始隆升到现在,龙门山冲断带的地壳隆升幅度大于10 ～ 12km,平均剥蚀厚度超过7.05km.     

西藏甲玛铜多金属矿床围岩蚀变特征及成矿流体运移规律浅析

甲玛铜多金属矿床围岩蚀变发育,可分为四期八个阶段,其中矽卡岩化、绢英岩化与成矿时空关系密切。通过对绢英岩化蚀变岩的质量平衡计算发现,导致绢英岩化围岩蚀变的热液为晚期岩浆分异的富挥发份的含矿硅质富钾酸性流体;并随着蚀变的发生发展,蚀变岩的主元素及成矿元素显示不同的迁移规律但表现出相似的蚀变流体运移趋势,即:以则古郎地区为中心,分别向铜山、铅山及莫古郎地区运移,由于铜山滑覆体阻挡,使得铜山地区蚀变较强,莫古郎地区较弱。     

Impact of the Ice-albedo Feedback on Meridional Temperature Gradient of Northern Hemisphere

This paper analyzes the variation of meridional temperature gradient (MTG) over mid-latitude and high-latitude of Northern Hemisphere continents during last 100 years using observational data. It is found that MTG over high-latitude of Northern Hemisphere continents has an increasing trend, but the simulation results of CMIP5 models show a decreasing trend. Results of this study showed the decrease of MTG over the high-latitude continents of Northern Hemisphere calculated by CMIP5 historical simulations mainly because the models of CMIP5 exaggerated ice-albedo feedback over high-latitude regions. A series of simulation results by energy balance climate models showed that ice-albedo feedback amplified the magnitude of warming in the global warming induced only by carbon dioxide, and the magnitude of warming in high latitude was much larger than that in low-latitude regions. Along with global warming, ice-albedo feedback has little influence on MTG in low-latitude, but can induce the decrease of MTG in high-latitude regions.     

SWBM模型在锡林河流域气候变化影响评价中的应用

以内蒙古地区的锡林河流域为研究对象,采用考虑融雪的水量平衡模型(SWBM模型),在对锡林河流域水文模拟的基础上,评估了流域水资源对气候变化的响应。结果表明:SWBM模型锡林河流域月径流过程具有较好的模拟效果,率定期和检验期的模型效率系数均超过60%,相对误差也均小于8%,在未来全球气候变化背景下,流域水资源以减少趋势为主,2030年之后,减少幅度将可能超过10%。     

Estimation of the surface energy balance in the Sahelian zone of Western Africa

Søgaard, Henrik: Estimation of the surface energy balance in the Sahelian zone of Western Africa. Geografisk Tidsskrift 88: 108- 115. Copenhagen 1988.

In studies of desertification in the Sahelian zone of Western Africa an improved knowledge of the water and surface energy balance is recognized to be of major importance. Based on micro-climatological measurements collected during an ongoing field study in the northern part of Burkina Faso, a number of methods for deriving surface energy balance are examined. It is found that for the actual case, with profile measurements restricted to two levels above the surface, exact values of the sensible heat flux can accurately be obtained by applying non-dimensional gradients based on the Monin-Obukhov turbulence theory. Utilization of the results for deriving actual evapotranspiration from standard observations is demonstrated, and the paper finally discusses applicability of the results in satellite remote sensing.     

Plan och verklighet i Helsingfors stadsförnyelse: Katajanokka (Skatudden)

Sundman, Mikael: Plan och verklighet i Helsingfors stadsförnyelse: Katajanokka. Geografisk Tidsskrift 83: 73–80. May 1., 1983.

Urban redevelopment in the capital of Finland is examined by comparisons between plans and development schemes for the city center of Helsinki and the peninsula of Katajanokka (Skatudden) situated just east of the city center.     

Commentaries on “Automated Geography”. Automated Geography and the DIDS (Decision Information Display System) Experiment

Age profiles of geographers having varying topical and areal subfields are compiled using the Guide to Graduate Departments of Geography in the United States and Canada, 1983–1984 and the 1982 AAG Directory. Major retirement trends for the next 10 to 20 years suggest that replacement of faculty may raise key appointment issues and priorities that may significantly change the nature of academic geography.     

Modèle hydrologique du Lac Tchad

Résumé

Le Lac Tchad est modélisé par un bilan de volume donnant ses niveaux et superficies de plans d'eau en fonction d'apports et pertes: débit des tributaires; pluie; évaporation; infiltration. Il est représenté par trois réservoirs (cuvette nord et archipel connectés à la cuvette sud) dont les niveaux de plan d'eau, distincts en période d'apports déficitaires (situation actuelle), sont confondus en période excédentaire (situation avant 1973). Suite aux observations de terrain, la cuvette nord est représentée avec un “réservoir sol” devant être rempli pour que l'eau puisse apparaître en surface. Le modèle utilise sept paramètres optimisés: intensité d'infiltration; profondeur du “réservoir sol”; quatre paramètres d’échange entre réservoirs; niveau de fond de l'archipel. Grâce aux données mesurées au sol ou par satellite (débits, précipitations, évaporation, niveaux et superficie de plans d'eau) il est calé sur la période 1970–1996 et validé sur la période 1956–2008.

Citation Bader, J.-C., Lemoalle, J. & Leblanc, M. (2011) Modèle hydrologique du Lac Tchad. Hydrol. Sci. J. 56(3), 411–425.     

沙漠陆面过程参数化与模拟

沙漠地区植被稀疏、干旱少雨,其陆面物理过程具有与全球其它地区显著不同的特点.本文利用巴丹吉林沙漠观测资料,分析和计算了地表反照率、比辐射率、粗糙度和土壤热容量、热传导系数等关键陆面过程参数,建立了适合于沙漠地区的陆面过程模式DLSM (Desert Land Surface Model),并与NOAH陆面过程模式的模拟结果和观测资料进行了比较.结果表明:巴丹吉林沙漠地表反照率为0.273,比辐射率为0.950,地表粗糙度为1.55×10^-3 m,土壤热容量和热扩散系数分别为1.08×10⁶ J·m^-3·K^-1和3.34×10^-7 m²·s.辐射传输、感热输送和土壤热传导过程是影响沙漠地区地表能量平衡的主要物理过程.通过对这三种过程的准确模拟检验,DLSM能够较准确地模拟巴丹吉林沙漠地气能量交换特征;短波辐射、长波辐射和感热通量的模拟结果与观测值间的标准差分别为7.98,6.14,33.9 W·m^-2,与NOAH陆面过程模式的7.98,7.72,46.6 W·m^-2的结果接近.地表反照率是沙漠地区最重要的陆面过程参数,地表反照率增大5%,向上短波辐射通量随之增加5%,感热通量则减小2.8%.本文研究结果对丰富陆面过程参数化方案,改进全球陆面过程模式、气候模式具有参考意义.     

Empirical mass balance modelling of South American tropical glaciers: case study of Antisana volcano,Ecuador

Abstract

Most Latin American glaciers are located in the tropical Andes. The melting processes of Glacier “15” on Antisana volcano were studied to understand the relationship between glacier retreat and natural climate variability and global climate change. Glaciers on the Antisana volcano are crucial sources of water as they feed the headwater rivers that supply Quito with potable water. The aim of this study was to build empirical models based on multiple correlations to reconstruct the mass loss of glaciers over a period of 10 years at three scales: local (data recorded by meteorological stations located around the volcano), regional (data from stations located around the country) and global (re-analysis data). Data quality was checked using graphical and statistical methods. Several empirical models based on multiple correlations were created to generate longer time series (42 and 115 years) of the mass balance for the glacier ablation zone. The long mass balance series were compared with the temperature variation series of the Earth’s surface in the Southern Hemisphere to estimate the relation between the mass balance and global warming. Our results suggest that the meteorological factors that best correlate with mass balance are temperature and wind.

Editor D. Koutsoyiannis