Environmental reconnaissance of the Shivee-Ovoo coalmine area, Mongolia

An exploratory investigation was conducted to assess the present conditions and evaluate the potential impacts of mining activities on soil and water environments at the Shivee-Ovoo coalmine area in Mongolia. Water quality analysis was conducted on samples from mine dewatering boreholes, a tailings dam, and drinking water sources around the mine area. In drinking water supplies of the area, concentrations of Mg, Fe, and F exceeded the levels set in Mongolian and World Health Organization guidelines. Water type and the principal components analysis indicated that water from the mine area and from public water-supply wells originated from the same aquifer. However, the water quality differed in shallow wells and deep wells because of bedrock differences and geochemical weathering processes, rather than climate effects such as from evaporation. The discharged water poses medium to high salinity hazard for use in irrigation, suggesting the need to manage its use in sustainable agriculture or projects to prevent desertification. The particle size distribution and fractal dimension values of soils revealed the dominance of fine to medium sands, which have strong potential for desertification. X-ray photoelectron spectroscopy analysis showed that the soils currently pose no apparent threat for acid rock drainage. Consequently, the open-pit mining of the study area shows no obvious environmental impact at present in its vicinity. However, for sustainable development and expansion of the mine, environmental changes should be continuously monitored, with consideration of possible measures for waste recycling.     

Parameterization and Application of Storm Surge/Tide Modeling Using a Genetic Algorithm for Typhoon Periods

A genetic algorithm was used to optimize the parameters of the two-dimensional Storm Surge/Tide Operational Model (STORM) to improve sea level predictions.The genetic algorithm was applied to nine typhoons that affected the Korean Peninsula during 2005-2007.The following model parameters were used:the bottom drag coefficient,the background horizontal diffusivity,Smagorinski’s horizontal viscosity,and the sea level pressure scaling.Generally,the simulation results using the optimized,mean,and median parameter values improved sea level predictions.The four estimated parameters improved the sea level prediction by 76% and 54% in the bias and root mean square error for Typhoon Kalmaegi (0807) in 2008,respectively.One-month simulations of February and August 2008 were also improved using the estimated parameters.This study demonstrates that parameter optimization on STORM can improve sea level prediction.     

Evaluation of pedestrian winds around tall buildings by numerical approach

Summary A numerical model based on the compressible flow equations has been used to simulate the pedestrian wind fields around the programming tall buildings in Beijing city. The model results are well agreed with those of the wind tunnel experiments. Since numerical model can provide the detailed flow field data at each grid point and each time step, it has a great advantage compared with the wind tunnel experiment in accurately evaluating the wind effects on pedestrian and other environmental issues. Furthermore, advance computational technology has made the numerical modeling become fast and cheaply. It is believed that the numerical simulation will play an increasingly more important role in the coming years, especially in dealing with wind environment.     

Problems of determining snow albedo for the high arctic: Research note

Abstract

The measurement of radiation fluxes suffers from inaccuracies at low solar elevations and this poses a problem for determining the snow albedo at high latitudes. From the data of Resolute, NWT, three situations were observed: (1) an often‐reported situation when albedo decreases with increasing solar elevation, (2) an inverse situation when albedo increases with increasing solar elevation and (3) no obvious relationship. There were also cases when albedo exceeded 100%. The possible causes for such anomalous conditions or for erroneous albedos include instrument response deviating from the cosine law, instrument tilt, sensing of the sun by the inverted pyranometer and change in the spectral quality of incoming radiation with changing solar height. However, omission of the radiation values measured during the period of low solar elevation will not seriously affect the prediction of snowmelt. In this note, we have identified the anomalies and suggested possible causes; but further investigations are required to verify the causative mechanisms.     

Validation of Sea Level Data in the East Asian Marginal Seas： Comparison between TOPEX／POSEIDON Altimeter and In-Situ Tide Gauges

In an effort to assess the reliability of satellite altimeter systems, the authors conduct a comparative analysis of sea level data that were collected from the TOPEX/POSEIDON (T/P) altimeter and 10 tide gauges (TG) near the satellite passing ground tracks. The analysis is made using datasets collected from marginal sea regions surrounding the Korean Peninsula at T/P cycles of 2 to 230, which correspond to October 1992 to December 1998. Proper treatment of tidal errors is a very critical step in data processing because the study area has very strong tide. When the T/P data are processed, the procedures of Park and Gamberoni (1995) are adapted to reduce errors associated with the tide. When the T/P data are processed in this way, the alias periods of M2, $2, and K1 constituents are found to be 62.1, 58.7, and 173 days repectively. The compatibility of the T/P and TG datasets are examined at various filtering periods.The results indicate that the low-frequency signals of the T/P data can be interpreted more safely with longer filtering periods (such as up to the maximum selected value of 200 days). When RMS errors for the 200-day low-pass filter period are compared with all 10 tidal stations, the values span the range of 2.8 to 6.7 cm. The results of a correlation analysis for this filtering period also show a strong agreement between the T/P and TG datasets across all stations investigated (e.g., p-values consistently less than 0.001). Hence according to the analysis, the conclusion is made that the analysis of surface sea level using satellite altimeter data can be made safely with reasonably extended filtering periods such as 200 days.     

Evaluation of the impact of pyrite oxidation on rock characteristics and environment by laboratory tests

Pyrite is a common and abundant sulfidic mineral subject to oxidation. The weathering characteristics of rock-bearing pyrite sometimes impose serious influences on the surrounding environment as the oxidation of pyrite (FeS₂) generates acid drainage that results in the acceleration of rock weathering and the discharge of heavy metals into the environment. Such an accelerated weathering of rocks can reduce its mechanical properties and therefore menace the stability of rock structures, such as excavated slopes and tunnels. The evolution of physical properties of rocks and the chemical composition of drainage were evaluated in this study by a weathering test using a double Soxhlet extractor for 1 month in a laboratory setting. Three groups of biotite gneiss classified according to their pyrite content were used for the Soxhlet extraction experiment (group A with less than 0.1 wt% of pyrite; group B with about 3.3 wt% of disseminated pyrite; group C with about 5.65 wt% of vein type pyrite). The massive groups A and B had limited weathering on the surface; however, group C with the pyrite vein experienced weathering on the surface as well as along the pyrite vein. The weathering type regulated by the occurrence of pyrite apparently controlled the mechanical properties of the rock samples and the chemistry of the drainage. Groups A and B showed no significant quick absorption ratio after the 1-month experiment; however, group C had about 10 % increase in value. The uniaxial compressive strength of the three groups decreased about 20, 10 and 45 % for groups A, B and C, respectively. The mechanical properties of the samples and the chemical compositions of the drainage indicate that the oxidation of pyrite contained in the samples accelerated weathering, resulting in deterioration of mechanical properties of the rocks, and could result in the discharge of heavy metals and acid into the environment with the drainage.     

Radiolarian-bearing conglomerate from the Hayang Group, the Kyongsang Supergroup, southeastern Korea

The non-marine Cretaceous Kyongsang Supergroup, which is divided into the Sindong, the Hayang and the Yuchon groups, is widely distributed in southeastern Korea. Radiolarian-bearing pebbles are collected from the conglomerates of the Kumidong and the Kisadong formations of the Hayang Group. The age of radiolarian fossils range from Late Permian to Middle Jurassic. In Korea, Permian to Middle Jurassic marine chert beds are not exposed. The directions of paleocurrents of the Kumidong and the Kisadong formations are mainly from the northeast to southwest. During Cretaceous time, the Mino-Tamba Belt, within which Permian to Middle Jurassic chert beds are exposed, is suggested to have been located northeast of the Kyongsang Basin. The radiolarian faunas of the Hayang Group are similar to those of the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan (e.g. the Ashio Belt). The provenance of the radiolarian-bearing pebbles collected from the Kumidong and the Kisadong formations is interpreted to be the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan.     

浅谈韩国的溶洞保护与开发—— 以三陟市新基面大耳里地区幻仙洞为例

韩国的溶洞开发虽然起步较晚，但其对溶洞的保护却有许多值得学习和借鉴之处，本文以幻仙洞为例介绍了韩国的溶洞开发现状、管理问题、相关法律法规及保护措施，并提出了作者的建议。     

Application of a newly developed column test device to analyze seawater transport in sandy soils

To verify the applicability of the time-continuous electrical conductivity (EC) measurement in analyzing the contaminant movement in the subsurface, a new column test device employing non-destructive four-electrode sensors was developed. Using the seawater to create a simple one-dimensional steady-flow condition, laboratory transport experiments were conducted and the EC breakthrough curves at different distances were obtained. Comparison between the EC breakthrough curves obtained from the EC sensors and those from the effluent solute chemical analysis showed that the estimated resident concentration from the EC breakthrough curves are useful in understanding solute transport in soils. The pore water velocity and longitudinal dispersion coefficient estimated using the computer code, CXTFIT, were found to be slightly underestimated, especially at sensors located at smaller distances from the outlet boundary. Results showed that the developed column test device employing the four-electrode sensors proposed in this study provides a non-destructive, convenient, and inexpensive means of evaluating the seawater transporting in soils.