阳离子交换系数及其在地下水Pb污染研究中的应用   总被引：2，自引：0，他引：2  

李铎  张伟 《水文地质工程地质》2002,29(5):12-14

本文首先计算了地下水中常见阳离子与被吸附Pb^2＋的交换系数，在此基础上利用实际地下水水质资料计算了天津市浅层地下水含水介质吸附最离子的当量分数，并利用吸附Pb^2 的当量分数估算了含水介质吸附Pb^2＋的量及地下咸水中Pb^2 的浓度的增大量。  相似文献   

陆面过程野外观测试验的进展   总被引：5，自引：0，他引：5  

胡隐樵 《地球科学进展》1992,7(3):37-42

Progresses in field observational experiments, which are three large international programs at present，about land一surface process are introduced comprehensively in the paper. Major results obtamed by the HAPEX and the FIFE and some preliminary results by the HEIFE are reviewed. Some problems, which should further be solved，in the field observational experiments are pointed out.
  相似文献   

发展地球科学大体系理论开拓人类文明的新前景     

陈荫祥 《遥感学报》1991,(3)

从人类发展需要及科学理论趋势出发论述地球科学各门类的大体系综合理论跃迁的观点。提出以地球深源岩浆热动力为主链的岩石圈、水圈、大气圈和生态环境圈的总体物质——热力运动高统帅性理论。展望新的高技术观(监)测系统。  相似文献   

Distributions of horizon-limited direct beam potential radiation in steep pastures     

Douglas G. Boyer  Charles M. Feldhake 《地球表面变化过程与地形》1991,16(1):1-10

Agricultural production from steep terrain is frequently limited to pasture systems, where forage harvesting is done by grazing animals. Intercepted solar radiation determines the energy available for forage production. A model was developed for estimating potential direct beam radiation in areas with a wide range of aspects, landscape positions, and various shadow sources. The model was applied to a small, steep pasture watershed in central Appalachia to determine the spatial distribution of potential direct beam radiation. Effective horizon was an important parameter affecting the energy budget of the study watershed. A simple means for estimating global radiation from the modelled potential direct beam radiation, given atmospheric transmissivity and cloudiness, was presented. When the proportion of global radiation that was diffuse radiation was increased the effective horizon was less important and the spatial variability of modelled radiation decreased.  相似文献   

空间电磁环境和日地系统能量过程的研究     

徐文耀 《地球物理学进展》1992,(1)

日地系统的能量耦合过程和该系统的整体行为是当前空间物理学的重要课题.本文简要综述了近年来,特别是第20届国际大地测量和地球物理联合会大会报导的某些研究成果,指出这些研究在人类认识近地空间电磁环境中的作用.  相似文献   

新疆6级以上地震年应变释放的概率分布     

王秀达  高国英 《内陆地震》1992,6(2):151-157

研究了新疆及邻近区域内1882—1990年6级以上地震年应变释放及各不同地震活动轮迥中地震年应变释放的概率分布,结果表明:区内6级以上地震年应变释放序列是按能量等级服从韦泊分布的。  相似文献   

Field determination of air-sea gas exchange by continuous measurement of radon-222     

Wolfgang Roether  Bernd Kromer 《Pure and Applied Geophysics》1978,116(2-3):476-485

Equipment has been developed for automatic measurement of the radon dissolved in sea water, with the aim of determining gas exchange rates at sea on the basis of the radon-222 deficiency in the mixed layer with respect to its parent nuclide radium-226. The equipment will be employed to obtain, over an extended period at fixed position, repeated measurements of the vertically integrated radon deficiency. The repetition period will be 2 hours, and sampling will be by a winch-operated submersible pumping system which will continuously scan the radon-deficient layer. The repeated measurements will allow to derive gas exchange rates even under transient meteorological conditions. As opposed to this, radon work carried out to date relied on isolated deficiency measurements and stationary conditions were commonly assumed (the deficiency relaxation time is about 5 days), which, under transient conditions, may lead to considerable errors. Equipment tests have been made at sea and the first integrated-deficiency measurements were obtained on the RSSChallenger in July 1977. Field programs are in preparation for JASIn (Joint Air-Sea Interaction, July–September 1978) and FGGE (First GARP Global Experiment, January–July 1979). The ultimate goal is a parameterization of the gas exchange rate in terms of external parameters, primarily wind speed.  相似文献   

Regional energetics over the North Pacific,South China Sea and the Indonesian seas during winter     

Takio Murakami 《Pure and Applied Geophysics》1977,115(5-6):1283-1301

The energy equation was applied to four limited regions to investigate the basic mechanisms through which area-averaged eddy kinetic energy is maintained during the northern winter. The regions selected for this study are as follows: extratropical North Pacific (24.2°N–44.6°N, 130°E–150°W), tropical eastern North Pacific (0°–19.6°N, 170°W–110°W), South China Sea and. Bay of Bengal (0°–19.6°N, 80°E–140°E), and Timor Sea and eastern Indian Ocean (0°–19.6°S, 80°E–140°E). The zonally averaged upper flows over the first region were found to be barotropically stable. In contrast, they were barotropically unstable over the second region; namely, eddy motions over the tropical eastern North Pacific are maintained by receiving energy from zonal flows via barotropic interaction. The third and fourth regions are characterized by the importance of the conversion process between eddy available potential and eddy kinetic energy.Contribution No. 77-5, Department of Meteorology, University of Hawaii, USA.  相似文献   

Glacio-Meteorological Investigations On Vatnajökull, Iceland, Summer 1996: An Overview   总被引：1，自引：0，他引：1  

J. Oerlemans  H. Björnsson  M. Kuhn  F. Obleitner  F. Palsson  C.J.P.P. Smeets  H. F. Vugts  J. De Wolde 《Boundary-Layer Meteorology》1999,92(1):3-24

We give an overview of a glacio-meteorological experiment carried out in the summer (melt season) of 1996 on the largest European ice cap, Vatnajökull, Iceland (area 8000 km²; altitude range: from sea level to about 2000 m). The main goal was to understand how the energy used in the melting of snow and ice is delivered to the surface. Many meteorological stations were operated simultaneously on the ice cap, at almost all of which profile measurements were made. Cable balloons and radiosondes were used to probe the vertical structure of the boundary layer. It appears that the flow near the surface is katabatic most of the time, with the height of the wind maximum varying between a few metres and a few tens of metres. It is only during the passage of intense storms that the katabatic wind in the melt zone disappears. Global radiation increases significantly with altitude. Surface albedo varies enormously in space and time, with very low values ( 0.1) being found at many places because of the melt out of volcanic ash layers. If we consider the total melt in the period 22 May–31 August 1996, we conclude that radiation typically provides two-thirds of the melt energy, and turbulent exchange of heat one-third. At locations high on the glacier, turbulent exchange becomes less significant.  相似文献   

Forest-Air Fluxes Of Carbon, Water And Energy Over Non-Flat Terrain   总被引：9，自引：0，他引：9  

Xuhui Lee  Xinzhang Hu 《Boundary-Layer Meteorology》2002,103(2):277-301

A field study of surface-air exchange of carbon, water, and energy was conducted at a mid-latitude, mixed forest on non-flat terrain to investigate how to best interpret biological signals from the eddy flux data that may be subject to advective influences. It is shown that during periods of Southwest winds (sector with mild topography), the eddy fluxes are well-behaved in terms of energy balance closure, the existence of a constant flux layer, consistency with chamber observations and the expected abiotic controls on the fluxes. Advective influences are evident during periods with wind from a steep (15%) slope to the Northeast of the tower. These influences appear more severe on CO₂ flux, particularly in stable air, than on the energy fluxes. Large positive flux of CO₂ (> 23 mol m^-2 s^-1) occurs frequently at night. The annual sum of the carbon flux is positive, but the issue about whether the forest is a source of atmospheric carbon remains inconclusive.Attempts are made to assess vertical advectionusing the data collected on a single tower. Over the Southwestsector, vertical advection makes a statistically significant but small contribution to the 30-min energy imbalance and CO₂ flux variations. Contributions by horizontal advection may be larger but cannot be verified directly by the current experimental method.  相似文献