Estimating the relative yields of Novaya Zemlya tests by waveform intercorrelation     

R. W. Burger  L. J. Burdick  T. Lay 《Geophysical Journal International》1986,87(3):775-800

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Impact of climate change on the persistent turbidity issue of a large dam reservoir in the temperate monsoon region     

Hyungseok Park  Sewoong Chung  Eunju Cho  Kyoungjae Lim 《Climatic change》2018,151(3-4):365-378

Long-term discharge of turbid water from reservoirs after flood events is a major socioenvironmental problem in many countries, including Korea. This study used a suite of mathematical models to simulate the fate of turbidity flows in the Soyanggang Reservoir in Korea, an important source of drinking water for the Seoul Capital Area, in response to extreme floods based on the Representative Concentration Pathway 4.5 climate scenario. It evaluated the effectiveness of the selective withdrawal facility (SWF), installed recently in the Soyanggang Reservoir to control persistent turbidity. Extreme floods with a maximum daily inflow rate greater than the historical maximum observed in 2006 were projected to occur four times in this century. The fate and transport of turbidity flows were highly influenced by both the thermal stability of the reservoir and the season in which the flood event occurred. Thus, SWF operations should consider the timing of extreme events (i.e., the imminence of the autumn turnover) to mitigate the impact of high turbidity on the water supply and downstream ecosystem. It was found to be ineffective under extreme events if these occurred in two consecutive years. Current reservoir operations, which rely heavily on the SWF, are likely to be inadequate to overcome the negative effects of extreme-turbidity events on reliably providing safe water supplies. Coping with the worst event expected to occur in the future would require additional countermeasures such as bypassing high-turbidity water.  相似文献   

Development of an Operational Hybrid Data Assimilation System at KIAPS     

In-Hyuk Kwon  Hyo-Jong Song  Ji-Hyun Ha  Hyoung-Wook Chun  Jeon-Ho Kang  Sihye Lee  Sujeong Lim  Youngsoon Jo  Hyun-Jun Han  Hanbyeol Jeong  Hui-Nae Kwon  Seoleun Shin  Tae-Hun Kim 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(1):319-335

This study introduces the operational data assimilation (DA) system at the Korea Institute of Atmospheric Prediction Systems (KIAPS) to the numerical weather prediction community. Its development history and performance are addressed with experimental illustrations and the authors’ previously published studies. Milestones in skill improvements include the initial operational implementation of three-dimensional variational data assimilation (3DVar), the ingestion of additional satellite observations, and changing the DA scheme to a hybrid four-dimensional ensemble-variational DA using forecasts from an ensemble based on the local ensemble transform Kalman filter (LETKF). In the hybrid system, determining the relative contribution of the ensemble-based covariance to the resultant analysis is crucial, particularly for moisture variables including a variety of horizontal scale spectra. Modifications to the humidity control variable, partial rather than full recentering of the ensemble for humidity further improves moisture analysis, and the inclusion of more radiance observations with higher-level peaking channels have significant impacts on stratosphere temperature and wind performance. Recent update of the operational hybrid DA system relative to the previous 3DVar system is described for detailed improvements with interpretation.  相似文献   

Adsorption kinetics and intraparticulate diffusivities of Hg, As and Pb ions on unmodified and thiolated coconut fiber   总被引：9，自引：9，他引：0  

J. C. Igwe M.Sc.  D.CHE  M.Eng.  Ph.D.  A. A. Abia M.Sc.  Ph.D.  C. A. Ibeh B.Sc. 《International Journal of Environmental Science and Technology》2008,5(1):83-92

As, Hg and Pb are examples of heavy metals which are present in different types of industrial effluents responsible for environmental pollution. Their removal is traditionally made by chemical precipitation, ion-exchange and so on. However, this is expensive and not completely feasible to reduce their concentrations to the levels as low as required by the environmental legislation. Biosorption is a process in which solids of natural origin are employed for binding the heavy metal. It is a promising alternative method to treat industrial effluents, mainly because of its low cost and high metal binding capacity. The kinetics was studied for biosorption experiments using coconut fiber for As (III), Hg (II) and Pb (II) ions adsorption. The specific surface area and surface charge density of the coconut fiber are 1.186×10²⁵ (m²/g) and 5.39 ×10²⁴ (meq/m²), respectively. The maximum adsorption capacity was found to be the highest for Pb (II) followed by Hg (II) and As (III). The modification of the adsorbent by thiolation affected the adsorption capacity. Equilibrium sorption was reached for the metal ions at about 60 min. The equilibrium constant and free energy of the adsorption at 30 °C were calculated. The mechanism of sorption was found to obey the particle-diffusion model. The kinetic studies showed that the sorption rates could be described by both pseudo first-order and pseudo second-order models. The pseudo second-order model showed a better fit with a rate constant value of 1.16 × 10^?4/min. for all three metal ions. Therefore, the results of this study show that coconut fiber, both modified and unmodified, is an efficient adsorbent for the removal of toxic and valuable metals from industrial effluents.  相似文献   

THE ADVERSE IMPACT OF HUMAN ACTIVITIES ON FLOOD CONTROL IN THE HUAIHE BASIN     

Hugen ZhU Associate Prof  Dept. Of Civil Eng.  Hefei University of Technology  Hefei  China Zhaoyin WANG Prof  Dr. International Research  Training Center on Erosion  Sedimentation  P.O. Box  Beijing China Dieter PRINZ Prof. 《国际泥沙研究》1997,(3)

LIN~DUCnONTheHuaiheBasinislOCatedbetWeen31"-36"llorthemlahtudeand112"-121"easternlongitude,andcoversatotalareaofabout269,000sq.kin,OfwhichthemountainousandhillyareasocCUPyl/3,theplainsandlow-iringland2/3.ThebasinelicitSsalientphysicalgeographicalfeatllTesasfollowsf(l)Thereisnoobviousmountaindividebe~ntheWatershedoftheriVerandtheYellowforerBasinaswellastheYangtZeRadBasin.MostofthetributariesinthenoalbudoftheHuaiheforertakethesouthdikesOftheYellowherasthedivide.(2)TheriVerbedofthetr…  相似文献   

Land response to atmosphere at different resolutions in the common land model over East Asia     

Daeun Kim  Yoon-Jin Lim  Minseok Kang  Minha Choi 《大气科学进展》2016,33(3):391-408

Towards a better understanding of hydrological interactions between the land surface and atmosphere, land surface models are routinely used to simulate hydro-meteorological fluxes. However, there is a lack of observations available for model forcing, to estimate the hydro-meteorological fluxes in East Asia. In this study, Common Land Model (CLM) was used in offline-mode during the summer monsoon period of 2006 in East Asia, with different forcings from Asiaflux, Korea Land Data Assimilation System (KLDAS), and Global Land Data Assimilation System (GLDAS), at point and regional scales, separately. The CLM results were compared with observations from Asiaflux sites. The estimated net radiation showed good agreement, with r =0.99 for the point scale and 0.85 for the regional scale. The estimated sensible and latent heat fluxes using Asiaflux and KLDAS data indicated reasonable agreement, with r = 0.70. The estimated soil moisture and soil temperature showed similar patterns to observations, although the estimated water fluxes using KLDAS showed larger discrepancies than those of Asiaflux because of scale mismatch. The spatial distribution of hydro-meteorological fluxes according to KLDAS for East Asia were compared to the CLM results with GLDAS, and the GLDAS provided online. The spatial distributions of CLM with KLDAS were analogous to CLM with GLDAS, and the standalone GLDAS data. The results indicate that KLDAS is a good potential source of high spatial resolution forcing data. Therefore, the KLDAS is a promising alternative product, capable of compensating for the lack of observations and low resolution grid data for East Asia.  相似文献   

Detecting climate adaptation with mobile network data in Bangladesh: anomalies in communication,mobility and consumption patterns during cyclone Mahasen     

Xin Lu  David J. Wrathall  Pål Roe Sundsøy  Md. Nadiruzzaman  Erik Wetter  Asif Iqbal  Taimur Qureshi  Andrew J. Tatem  Geoffrey S. Canright  Kenth Engø-Monsen  Linus Bengtsson 《Climatic change》2016,138(3-4):505-519

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Firm entry modes and Chinese business networks: Malaysian investments in Vietnam          下载免费PDF全文

Guanie Lim 《Singapore journal of tropical geography》2016,37(2):176-194

This paper examines the Malaysian Chinese firms that have expanded into Vietnam. Based on research and qualitative personal interviews with Malaysian Chinese firms that have invested in Vietnam, the paper unpacks the entry modes that these firms have undertaken. It argues that the Malaysian Chinese firms prefer joint ventures in their Vietnamese businesses to wholly‐owned subsidiaries and personal direct investments. This paper also argues that such investments are often embedded in social and intraethnic ties, which connect Malaysian Chinese firms with Vietnam's ethnic Chinese businessmen. To this end, these firms tend to rely on informal ties and nonmarket institutions in the form of the ethnic Chinese business networks. Nevertheless, the Malaysian Chinese firms are not averse to collaborating with nonethnic Chinese firms that enjoy a good relationship with the Vietnamese state. This observation is especially marked in the property and construction, and finance sectors.  相似文献   

Buckling Propagation in Marine Pipelines     

Lin Zhongqin  Shen Huishen Chen Tieyun Dr. Associate Professor  Dept. of Mechanical Eng.  Shanghai Jiao Tong University  Shanghai Professor  Dept. of Civil Engineering  Shanghai Jiao Tong University  Shanghai Professor  Dept. of Naval Arch  and Ocean Eng.  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1993,(1)

The buckling propagation in marine pipelines is studied by means of the cylindrical shell model in this paper. Several parameters including geometrical parameter D/ T, L/ D, physical parameter E and σy are discussed. The computed results are compared with the available experimental data and other computed results, it is found that the present results are closer to the experimental results than other computed results.  相似文献   

A second-order particle tracking method     

Seok Lee  Heung-Jae Lie  Kyu-Min Song  Chong-Jeanne Lim 《Ocean Science Journal》2005,40(4):201-208

An accurate particle tracking method for a finite difference method model is developed using a constant acceleration method. Being assumed constant temporal and spatial gradients, the new method permits temporal-spatial variability of particle velocity. Test results in a solid rotating flow show that the new method has second-order accuracy. The performance of the new method is compared with that of other methods; the first-order Euler forward method, and the second-order Euler predictorcorrector method. The new method is the most efficient method among the three. It is more accurate and efficient than the other two.  相似文献