准地转三层模式天气值预报方法的试验研究

作者首先根据温度局地变化的分析说明三层模式常常是必要的。然后作者用较普遍的准地转三层模式,试算了大范围高空温压场的倾向。所计算的是乌拉尔阻塞流型发展关键时刻的例子。作者的计算结果说明这种阻塞流型形成的预报必须使用三层模式,主要是因为与阻塞流型中高、低压切断有关的负变高,只有使用三层模式才报得好。根据三层模式的公式,作者并求出大范围天气系统发展的规则:即冷(暖)平流向上增强(减弱),那末等压面的位势高度升高(低槽减弱、高压脊加强);冷(暖)平流向上减弱(增强),那末等压面的位势高度降低(低槽加强、高压脊减弱)。也就是说,—舵所接受的暖平流使脊加强,冷平流使槽加深这规则是有条件的。作者还指出风场的逼近的需要和困难。特则是现有高空风观测和电码难以直接用来计算辐散。在计算方面作者给出了一个对 Poisson 方程适用的成群放松的格式。     

Integrating spatial data analysis functionalities in a GIS environment: Spatial Analysis using ArcGIS Engine and R (SAAR)

Spatial data analysis (SDA) tools to efficiently handle and explore spatial data have become readily available. Although these SDA tools have their own strengths and purposes, they suffer from limited support in terms of a development environment offering easy customization and high extensibility, a strength of open source software. This article presents a standalone software package for SDA in a geographic information system (GIS) environment, called Spatial Analysis using ArcGIS Engine and R (SAAR), which provides an integrated GIS and SDA environment. A set of SDA tools in SAAR utilizes functions in R using R.NET, while other tools were developed in .NET independent of R. SAAR provides an efficient working environment for both general and advanced GIS users. For general GIS users with limited programming skills, SAAR furnishes advanced SDA tools in a popular ArcGIS environment with graphical user interfaces. For advanced GIS users, SAAR offers an extensible GIS platform to help them customize and implement SDA functions with relatively little development effort. This article demonstrates some functionalities of SAAR using census data for Texas counties.     

Fully nonlinear wave-body interactions with surface-piercing bodies

Fully nonlinear wave-body interactions for stationary surface-piercing single and double bodies are studied by a potential-theory-based fully nonlinear 2D numerical wave tank (NWT). The NWT was developed in time domain by using boundary element method (BEM) with constant panels. MEL free surface treatment and Runge–Kutta fourth-order time integration with smoothing scheme was used for free-surface time simulation. The acceleration-potential scheme is employed to obtain accurate time derivative of velocity potential. Using the steady part of nonlinear force time histories, mean and a series of higher-harmonic force components are calculated and compared with the experimental and numerical results of other researchers. The slow-decaying second-harmonic vertical forces are investigated with particle velocities and corresponding body pressure. Typical patterns of two-body interactions, shielding effect, and the pumping/sloshing modes of water column in various gap distances are investigated. The pumping mode in low frequencies is demonstrated by the comparison of velocity magnitudes.     

Geology, Mineralogy and Geochemistry of Carbonate Replacement-Type Lead-Zinc-Silver Deposits in Janggun Mine, Republic of Korea

INTRODUCTIONThe Janggun mine,Republic of Korea,is located in thesoutheast of the Seoul,about latitude36°5 1′N and longitude12 9°0 4′E. In this mine area is situated the Bonghwa m ineral-ized zone of the Taebaegsan mining district,Korea.The geo-logic setting of the region was described as the Samgeum riQuadrangle(Kim et al.,196 2 ) .The general and local geolo-gy near the mine area have been studied by L ee (196 7) ,Hwang and Reedman(1975 ) .This mine consists of four min-eral de…     

韩国东海Ulleung盆地天然气水合物沉积层的地震属性分析

地震属性可以由多种地震子波的特征来定义。并且根据不同的标准分类。选择叠前地震数据特征可提供丰富的诸如偏移和方向的资料,此次研究中,我们将限制叠后地震数据以提取地震属性,叠后地震数据可以通过子波特征和瞬时特征来分类。     

Does the restoration of an inner-city stream in Seoul affect local thermal environment?

Summary Changes in local thermal environment associated with the restoration of an inner-city stream in Seoul, Korea, are investigated using observational data. The stream, called the Cheonggye stream, which had been hidden and covered with cement/asphalt for 46 years, runs 5.8 km eastward through a central region of Seoul. Intensive observations were made in the stream area for a number of summertime periods before, during, and after the stream restoration to detect the effects of the stream on local environment and to quantify them. It is estimated that after the stream restoration the near-surface temperature averaged over the stream area dropped by 0.4 °C, with the largest local temperature drop being 0.9 °C. However, it cannot be stated that this 0.4 °C temperature drop is due entirely to the stream effect only, because synoptic-scale and local-scale weather conditions during the two periods were inevitably not identical. The stream effect on air temperature is also evident in the temperature distribution along a street traversing the stream. In the daytime after the stream restoration, the sensible heat flux was greatly reduced and the ratio of sensible heat flux to net radiative flux dramatically decreased. These first-time results of the restored-stream effects on urban thermal environment could contribute to the scientific basis of urban planning which aims to make a large city comfortable to live in and nature- and environment-friendly. Authors’ addresses: Yeon-Hee Kim, Il-Soo Park, Hae-Jung Koo, and Jae-Cheol Nam, Meteorological Research Institute, Korea Meteorological Administration, Seoul 156-720, Korea; Sang-Boom Ryoo, Suwon Meteorological Office, Korea Meteorological Administration, Suwon 441-856, Korea; Jong-Jin Baik, School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, Korea     

A numerical model for estimating groundwater flux from subsurface temperature profiles

A simple numerical model is presented for estimating vertical groundwater flux from transient subsurface temperature profiles obtained from field measurements. The model developed utilizes the MacCormack scheme, which is based on the Finite Difference Method (FDM), for solving the governing partial differential equation of convection–diffusion heat transport with appropriate initial and boundary conditions within the subsurface. In order to validate the model, numerical solutions obtained for the study area located in the Nagoka plain, Japan are compared with the published measured data and results obtained by others. Results obtained show good agreement and fit the observed data with a correlation coefficient, R², of 0·88. The estimated groundwater flux is 1·85 × 10⁻⁷ m s⁻¹. Sensitivity analyses were also carried out to investigate the effect of variations in groundwater fluxes, thermal properties and the annual thermal variability due to climatic changes on the transient subsurface temperature profiles and to have a better understanding of the subsurface thermal dynamics. A substantial effect of annual climatic variability is observed on the temporal distributions of temperature depth profiles, and a better estimate of thermal parameters is required to estimate vertical groundwater flux. The largest change in subsurface temperature depth profiles due to groundwater flux over a year is within ± 4 °C. The influence of groundwater flux on subsurface temperature distributions in space and time may be more pronounced in areas where the top of the saturated layer fluctuates considerably. Variation in thermal diffusivity results in temperature change up to ± 1·5% and may cause change in groundwater flux estimate by ± 18%. The model presented has merits over analytical solutions (type curve matching techniques) in terms of suitability and applicability to real field problems, and can be a good asset to hydrological models as quantifying groundwater recharge or deducing it from other quantities, such as rainfall, evapotranspiration and runoff, is often complicated. Copyright © 2007 John Wiley & Sons, Ltd.