用同位素数据说明碳氢化合物中H_2S和CO_2的成因

<正> 酸性化合物总是存在于碳氢化合物中,其含量从百分之一到百分之几十。一方面,它们是讨厌的杂质(特别是H_2S),给勘探和野外工作带来很大麻烦;另一方面,它们又可能是难得的原料来源。由于在苏联几个地区——里海凹陷、Amu-Darya陆槽和西西伯利亚地台——发现了含     

激发极化的数字模拟

前言在直流电法勘探中,已经把几种数字方法用于模拟任意电阻率的分布。由于计算机的高速发展,这些方法在近十年来已变成是切实可行的了。两种最常用的方法是有限单元(FE)法和有限差分(FD)法。     

城市设置理论

上个世纪,人们对城市和定居点的设置位置和分布形态相继进行了研究。研究者们在许多原理方面各自做出了重要贡献。但一方面由于研究结果存在着差异,且涉足的领域未能协调起来,另一方面,由于问题本身十分复杂,涉及到了多种变量,该理论体系一直处于缓慢的进展之中,这与在工业设置领域研究所取得的进展形成了鲜明的对照。Von Thünen 所著的《Der isolierte staat》是现代第一部就这一问题进行了理论阐述的重要作品,它首版于1826年。     

超高频调制光波测距仪相位偏移法同步检测

迄今为止,所有成功的超高频调制光波测距仪均采用频偏法进行同步检测来实现距离测量。本文针对频偏法存在的问题,提出相位偏移法进行同步检测,并介绍实现相位偏移法的具体方案。     

由风成地貌揭示的北美洲中部晚冰期环流

晚冰期风成地貌(沙丘、风蚀脊、凤蚀盆地等)的大陆调查——根据陆地卫星成象和高空航空摄影,已经有可能详细的重建北美中部威斯康星冰期之末的气流。在北美中部已识别出晚更新世风成地貌450多处。把这些风成地貌的走向与毗邻的现代沙丘进行比较,同时也与遍布美国和加拿大南部的167个气象站计算的沙玫瑰图结果(Sand rose resultants)进行比较。在许多地区,晚冰期地区风方向与现代环流有40°—90°的相位差。放射性碳年龄测定表明,风向活动的极盛期出现在距今约14000年。分布于大陆的残存风成地貌使有可能重建对流层上部,晚冰期环流型。控制体系是中纬度地区(北纬40°—50°)的三个行星波,而现代环流典型地呈现出四个或五个波。在中纬度地区持续的三个罗斯贝波产生的气修影响包括:增加了从落基山脉东部到大西洋沿岸广大地形引起的低压槽地区内的干旱:为美国西部的盆地和山脉区增加了水汽的供给。最后,讨论劳伦特(Laurentide)冰原质量平衡模式的含义。     

THE SENSITIVITY OF NUMERICAL SIMULATION TO OROGRAPHY SPECIFICATION IN THE LOW RESOLUTION SPECTRAL MODEL－PART I: THE EFFECTS OF OROGRAPHY ON THE ATMOSPHERIC GENERAL CIRCULATION

In order to identify the sensitivity of the numerical simulation to the orography specification in a low resolution spectral model, two sets of numerical experiments for full-mountain and no-mountain cases are performed. By comparing the results, it is possible to determine the eflects of mountains on the atmospheric general circulation.This is a global, spectral model incorporating the primitive equations sugmented by physical parameterization and mountains, with five equally-spaced sigma levels in the vertical ang a triangular truncation at wavenum-ber 10 in the horizontal.Analysis of results supports earlier work by demonstrating that the low resolution global spectral model is capable of simulating the major features of global general circulation and indicates that it is necessary to consider the effects of mountains on stationary disturbances in the numerical simulation. The simulations show that topography plays an important role in intensifying heat sources for maintenance of disturbances.All the     

Transboundary impacts on regional ground water modeling in Texas

Recent legislation required regional grassroots water resources planning across the entire state of Texas. The Texas Water Development Board (TWDB), the state's primary water resource planning agency, divided the state into 16 planning regions. Each planning group developed plans to manage both ground water and surface water sources and to meet future demands of various combinations of domestic, agricultural, municipal, and industrial water consumers. This presentation describes the challenges in developing a ground water model for the Llano Estacado Regional Water Planning Group (LERWPG), whose region includes 21 counties in the Southern High Plains of Texas. While surface water is supplied to several cities in this region, the vast majority of the regional water use comes from the High Plains aquifer system, often locally referred to as the Ogallala Aquifer. Over 95% of the ground water demand is for irrigated agriculture. The LERWPG had to predict the impact of future TWDB-projected water demands, as provided by the TWDB, on the aquifer for the period 2000 to 2050. If detrimental impacts were noted, alternative management strategies must be proposed. While much effort was spent on evaluating the current status of the ground water reserves, an appropriate numerical model of the aquifer system was necessary to demonstrate future impacts of the predicted withdrawals as well as the effects of the alternative strategies. The modeling effort was completed in the summer of 2000. This presentation concentrates on the political, scientific, and nontechnical issues in this planning process that complicated the modeling effort. Uncertainties in data, most significantly in distribution and intensity of recharge and withdrawals, significantly impacted the calibration and predictive modeling efforts. Four predictive scenarios, including baseline projections, recurrence of the drought of record, precipitation enhancement, and reduced irrigation demand, were simulated to identify counties at risk of low final ground water storage volume or low levels of satisfied demand by 2050.     

THE EFFECTS OF TOPOGRAPHY ON THE SUMMER ATMOS-PHERIC ENERGETICS OF THE NORTHERN HEMISPHERE IN A LOW-RESOLUTION GLOBAL SPECTRAL MODEL

An analysis is made of the effects of topography on the summer atmospheric energetics of the Northern Hemisphere in a low-resolution global spectral model. The numerical model is a global, spectral, primitive equation model with five equally spaced sigma levels in the vertical and triangular truncation at wavenumber 10 in the horizontal. The model includes comparatively full physical processes.Each term of the energy budget equations is calculated in four specific latitudinal belts (81.11°S-11.53°S; 11.53°S-11.53°N; 11.53°N-46.24°N; 46.24°N-81.11°N) from a five-year simulation with mountains and a one-year simulation without mountains, respectively. Differences between them are compared and statistically tested. The results show that synoptical scale waves transport available potential energy and kinetic energy to long waves and increase conversion from available potential energy of the zonal flow to eddy’s and from the eddy kinetic energy to the zonal kinetic energy in region 3 (11.53°N-46.24°N) due to mountains; topography intensifies the atmospheric baroclinity in region 3, consequently the baroclinic conversion of atmosphere energy is increased. The seasonal characteristics associated with the summer atmospheric energy source in region 3 are caused by seasonal variation of the solar radiation and the land-ocean contrasts and independent of topographic effects. The mechanism of topographic effects on the increase of long wave kinetic energy is also discussed.