地理极点与地磁极点辨析

地理极点人们假想的地球旋转轴，穿过地心，与地球表面相交的两点，即地理北极和地理南极。地磁极点人们假想的地球磁轴，与地球表面相交的两点，即地磁北极和地磁南极。地理极点与地磁极点，通称地球极点。它们的相似之处，都位于地球的高纬地区，都能用于指示方向，与人...

先秦四极地理观的形成

四极地理观,指古代中国人对东西南北四极所至之地的看法。这一观念源于东夷及殷商文化,主要蕴含在《山海经》和《尚书·尧典》之中,后被战国学者继承、发展,这在《孟子》、《庄子》、《韩非子》、《吕氏春秋》、《楚辞》等著作中均有表现。先秦四极地理观主要表述为东至旸谷或大海、南至交趾、西至昧谷或流沙、北至幽都等,具有虚实参半的特点,并为后世所沿用,深刻影响了古代中国人对天下的认知。

Southern high latitude climate anomalies associated with the Indian Ocean dipole mode

Using a 23-year database consisting of sea level pressure, surface air temperature and sea surface temperature, the authors studied southern high latitude climate anomalies associated with IOD (Indian Ocean Dipole). Correlation analysis of the spatial variability regarding monthly sea level pressure, surface air tempera- ture, and sea surface temperature anomalies with IOD index suggests that IOD signal exists in southern high latitudes. The correlation fields exhibit a wavenumber-3 pattern around the circumpolar Southern Ocean. Lead-lag correlation analysis on the strongest correlation areas with IOD index shows that IOD in the tropical Indian Ocean responses to the southern high latitude climate almost instantaneously. It is proposed in the present paper that this connection is realized through atmospheric propagation rather than through oceanic one.

Do copepods inhabit hypersaline waters worldwide?A short review and discussion

A small number of copepod species have adapted to an existence in the extreme habitat of hypersaline water. 13 copepod species have been recorded in the hypersaline waters of Crimea （the largest peninsula in the Black Sea with over 50 hypersaline lakes）. Summarizing our own and literal_re data, the author concludes that the Crimean extreme environment is not an exception： copepod species dwell in hypersaline waters worldwide. There are at least 26 copepod species around the world living at salinity above 100; among them 12 species are found at salinity higher than 200. In the Crimea Cletocamptus retrogressus is found at salinity 360×10^-3 （with a density of 1 320 individuals/m^3） and Arctodiaptomus salinus at salinity 300×10^-3 （with a density of 343 individuals/m^3）. Those species are probably the most halotolerant copepod species in the world. High halotolerance of osmoconforming copepods may be explained by exoosmolyte consumption, mainly with food. High tolerance to many factors in adults, availability of resting stages, and an opportunity of long-distance transportation of resting stages by birds and/or winds are responsible for the wide geographic distribution of these halophilic copepods.

Determination Method for Shear Strength Parameters of Rock-Soil Mixtures Using Close-Range Photogrammetry and 3-D Limit Equilibrium Theory

Using a combination of close-range photogrammetry and three-dimensional(3-D) limit equilibrium theory, a determination method for the shear strength parameters of rock-soil mixture is presented. A close-range photogrammetry method is used for measurement of the 3-D terrain of the experimental target. Auto CAD Lisp and EXCEL VBA are used to perform 3-D limit equilibrium analysis of the stability of sliding mass and perform backanalysis of shear strength parameters. The presented method was used to determine the shear strength parameters of rock-soil mixtures at the Liyuan Hydropower Station. The 3-D terrain of sliding surface could be measured notably well using of closerange photogrammetry. The computed results reveal that the cohesion and friction angle of rock-soil mixtures were 3.15 k Pa and 29.88o for test A, respectively, and 4.43 k Pa and 28.30o for test B, respectively, within the range of shear strength parameters, as determined by field and laboratory tests. The computation of shear strength parameters is influenced by the mesh grid number, especially the cohesion of the rock-soil mixture. The application of close-range photogrammetry can reduce the siteworks and improve the computational efficiency and accuracy.

Study of Squeezed Excitons in Polar Semiconductors

Some properties of excitons in polar semiconductors are studied theoretically by means of squeezed state variational approach. This method makes it possible to consider bilinear terms of the phonon operators as well as linear terms arising from the Lee-Low-Pines （LLP）-like transformation. The exciton ground state energy and binding energy are calculated numerically. It is shown that the squeezing effect is significant in the case of strong exciton-phonon coupling region.

The Istituto Nazionale di Geofisica e Vulcanologia Data Management System for the Arctic Sciences

The brokering approach can be successfully used to overcome the crucial question of searching among enormous amount of data （raw and/or processed） produced and stored in different information systems. In this paper, authors describe the Data Management System the DMS （Data Management System） developed by INGV （Istituto Nazionale di Geofisica e Vulcanologia） to support the brokering system GEOSS （Global Earth Observation System of Systems） adopted for the ARCA （Arctic Present Climate Change and Past Extreme Events） project. This DMS includes heterogeneous data that contributes to the ARCA objective （www.arcaproject.it） focusing on multi-parametric and multi-disciplinary studies on the mechanism （s） behind the release of large volumes of cold and fresh water from melting of ice caps. The DMS is accessible directly at the www.arca.rm.ingv.it, or through the IADC （Italian Arctic Data Center） at http：//arcticnode.dta.cnr.it/iadc/gi-portal/index.jsp that interoperates with the GEOSS brokering system （http：//www.geoportal.org0 making easy and fast the search of specific data set and its URL.

Stability analysis and monitoring study of Jijia River landslide based on WebGIS

On the basis of in situ investigation and deformation monitoring of the Jijia River landslide （JJRL）, the rigid body limit equilibrium method and finite element method （FEM） were used to analyze the stability of the JJRL; the grey system theory method was applied to forecast the deformation trend of the JJRL; and the information system about the landslide deformation and monitoring, and forecasting systems based on the platform of the Web Geographical Information System （WebGIS） were developed, which can be used to analyze in situ monitoring data and predict the deformation of the landslide. The study results can be summarized as follows： （1） the JJRL is stable as a whole; the water content in the landslide has a great effect on its stability; （2） the developed Web Geographical Information System has realized many functions, including inputting, computing, inquiry, analyzing, and the function of forecasting; it has also realized the functions of distance data management, analysis, and forecasting based on the WebGIS; （3） the information resource can be shared by the WebGIS developed all over the world.

Global features and trends of the tropopause derived from GPS/CHAMP RO data

The global characteristics and trends of the tropopause physical parameters,height and temperature,obtained from the GPS/CHAMP radio occultation(RO) data in the period from Jul.2001 to Oct.2008,were modeled and analyzed in this work.The global distribution and variation of these parameters with latitude were estimated and analyzed using the Empirical Orthogonal Function(EOF),which was introduced to reveal the possible relationship between the tropopause variations and global climate change.The tropopause height and temperature varied with latitude.The results obtained by using the Empirical Orthogonal Function analysis suggested a recent rise in tropopause height and decrease in tropopause temperature;and also partly supported the argument that the global rise in the tropopause is consistent with global climate change.These results also revealed that the tropopause height increased mainly in the Polar regions,particularly in the South Polar region,as well as the regions where human activity is relatively significant,and decreased in the areas that are sparsely populated or have less human activity,such as the tropic region and south hemisphere.This paper also confirms that the GPS/LEO RO data are more reliable and can be effectively used to analyze the tropopause physical parameters.

Detection of crevasses over polar ice shelves using Satellite Laser Altimeter

Ice shelf breakups account for most mass loss from the Antarctic Ice Sheet as the consequence of the propagation of crevasses(or rift)in response to stress.Thus there is a pressing need for detecting crevasses’location and depth,to understand the mechanism of calving processes.This paper presents a method of crevasse detection using the ICESat-1/GLAS data.A case study was taken at the Amery Ice Shelf of Antarctica to verify the accuracy of geo-location and depth of crevasses detected.Moreover,based on the limited crevasse points,we developed a method to detect the peak stress points which can be used to track the location of the crack tips and to identify the possible high-risk area where an ice shelf begins to break up.The spatial and temporal distribution of crevasse depth and the spatial distribution of peak stress points of the Amery Ice Shelf were analyzed through 132 tracks in 16 campaign periods of ICESat-1/GLAS between 2003 and 2008.The results showed that the depth of the detected crevasse points ranged from 2 to 31.7 m,which were above the sea level;the crevasse that advected downstream to the front edge of an ice shelf has little possibility to directly result in breakups because the crevasse depth did not show any increasing trend over time;the local stress concentration is distributed mainly in the suture zones on the ice shelves.

发光

玛丽·韦瑟福德的绘画借鉴了自然和现代主义的绘画传统,经常将贝壳、海绵或生动的霓虹灯管组合在一起呈现。