Evaluation of groundwater quality in coastal areas: implications for sustainable agriculture   总被引：4，自引：1，他引：4  

Jin-Yong Lee  Sung-Ho Song 《Environmental Geology》2007,52(7):1231-1242

Seawater intrusion is a problem in the coastal areas of Korea. Most productive agricultural fields are in the western and southern coastal areas of the country where irrigation predominantly relies on groundwater. Seawater intrusion has affected agricultural productivity. To evaluate progressive encroachment of saline water, the Korean government established a seawater intrusion monitoring well network, especially in the western and southern part of the peninsula. Automatic water levels and EC monitoring and periodic chemical analysis of groundwater help track salinization. Salinization of fresh groundwater is highly associated with groundwater withdrawal. A large proportion of the groundwaters are classified as Na–Cl and Ca–Cl types. The Na–Cl types represent effects of seawater intrusion. The highest EC level was over 1.6 km inland and high Cl values were observed up to 1.2 km inland. Lower ratios of Na/Cl and SO₄/Cl than seawater values indicate the seawater encroachment. A linear relation between Na and Cl represents simple mixing of the fresh groundwater with the seawater. The saline Na–Cl typed groundwaters showed Br/Cl ratios similar to or less than seawater values. The Ca–HCO₃ type groundwaters had the highest Br/Cl ratios. Substantial proportions of the groundwaters showed potential for salinity and should be better managed for sustainable agriculture.  相似文献   

Distinct sedimentary processes reflected in the isotopic signatures of dolomitic concretions in the Miocene Pohang Basin (southwestern East Sea)     

Boo-Keun Khim  Kyung Sik Woo  Young Kwan Sohn 《Journal of Asian Earth Sciences》2007,29(5-6):939-946

Dolomitic concretions in diatomaceous hemipelagic sediments of the Miocene Pohang Basin in the southwestern East Sea (Sea of Japan) preserve distinct signals of two independent sedimentary processes, which controlled the extents of isotopic compositions. Variable δ¹⁸O (−9.1‰ to +0.7‰) and high δ¹³C (+3.1‰ to +17.9‰) values suggest that the concretions formed in the methanogenic zone with alteration of the residual mid-Miocene seawater by volcanogenic sediments. Remarkable δ¹⁸O and δ¹³C values show a strong linear relationship, indicating that distinctly independent depositional processes operated during the formation of the concretions. The degree of methanogenesis was enhanced during rapid hemipelagic sedimentation of organic-rich particles, resulting in higher δ¹³C values, and the effect of volcaniclastics was diluted, maintaining the original properties of ambient mid-Miocene seawater. In contrast, lower δ¹⁸O and ⁸⁷Sr/⁸⁶Sr values characterize the effect of volcaniclastic sediments that were transported by intermittent gravity flows and interacted with mid-Miocene seawater. The input of volcaniclastic sediment probably degraded the role of methanogenesis by lowering the contents of organic matter and thereby decreased the δ¹³C values within the concretions. Isotopic signals recorded within the concretions highlight understanding of the depositional environment and evolution of the pore-water chemistry.  相似文献   

Long‐term trend of precipitation and runoff in Korean river basins     

Deg‐Hyo Bae  Il‐Won Jung  Heejun Chang 《水文研究》2008,22(14):2644-2656

The spatial and temporal variations of precipitation and runoff for 139 basins in South Korea were investigated for 34 years (1968–2001). The Precipitation‐Runoff Modelling System (PRMS) was selected for the assessment of basin hydrologic response to varying climates and physiology. A non‐parametric Mann–Kendall's test and regression analysis are used to detect trends in annual, seasonal, and monthly precipitation and runoff, while Moran's I is adapted to determine the degree of spatial dependence in runoff trend among the basins. The results indicated that the long‐term trends in annual precipitation and runoff were increased in northern regions and decreased in south‐western regions of the study area during the study period. The non‐parametric Mann–Kendall test showed that spring streamflow was decreasing, while summer streamflow was increasing. April precipitation decreased between 15% and 74% for basins located in south‐western part of the Korean peninsula. June precipitation increased between 18% and 180% for the majority of the basins. Trends in seasonal and monthly streamflow show similar patterns compared to trends in precipitation. Decreases in spring runoff are associated with decreases in spring precipitation which, accompanied by rising temperatures, are responsible for reducing soil moisture. The regional patterns of precipitation and runoff changes show a strong to moderate positive spatial autocorrelation, suggesting that there is a high potential for severe spring drought and summer flooding in some parts of Korea if these trends continue in the future. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Development of a skill assessment tool for the Korea operational oceanographic system   总被引：1，自引：1，他引：0  

CHO Kyoung-Ho  CHOI Jin-Yong  JEONG Sang-Hun  CHOI Jung-Woon  KWON Jae-Il  PARK Kwang-Soon 《海洋学报(英文版)》2013,32(9):74-81

A standard skill assessment(SA) tool was developed and implemented to evaluate the performance of operational forecast models in the Korea operational oceanographic system.The SA tool provided a robust way to assess model skill in the system by comparing predictions and observations,and involved the computation of multiple skill metrics including correlation and error skills.User-and system-based acceptance criteria of skill metrics were applied to determine whether predictions were acceptable for the system.To achieve this,the tool produced a time series comparison plot,a skill score table,and an advanced summarized diagram to effectively demonstrate the multiple skill scores.Moreover,the SA was conducted to evaluate both atmospheric and hydrodynamic forecast variables.For the atmospheric variables,acceptable error criteria were preferable to acceptable correlation criteria over short timescales,since the mean square error overwhelmed the observation variance.Conversely,for the hydrodynamic variables,acceptable root mean square percentage error(e.g.,p erms) criteria were preferable to acceptable error(e.g.,erms) criteria owing to the spatially variable tidal intensity around the Korean Peninsula.Furthermore,the SA indicated that predetermined acceptance error criteria were appropriate to satisfy a target central frequency(fc) for which errors fell within the specified limits(i.e.,the fc equals 70%).  相似文献   

Simulation of wind-induced near-inertial oscillations in a mixed layer near the east coast of Korea in the East/Japan Sea     

NAM SungHyun  PARK Young-Gyu 《海洋学报(英文版)》2013,32(9):11-20

Using a simple damped slab model,it was possible to show that a local wind induced 88%(15 of 17)of the near-inertial oscillations(NIO)observed in the mixed layer near the east coast of Korea from 1999 to 2004.The model,however,overestimated the energy level in about two-thirds of the simulated cases,because the slab model was forced with winds whose characteristic period was shorter than the damping time scale of the model at 1.5 d.At the observation site,due to typhoons and orographic effects,high-frequency wind forcing is quite common,as is the overestimation of the energy level in the slab model results.In short,a simple slab model with a damping time-scale of about 1.5 d would be enough to show that the local wind was the main energy source of the near-inertial energy in this area,but the model could not be used to accurately estimate the amount of the work done by the wind to the mixed layer.  相似文献   

When seed fails: The contested nature of neoliberalism in South Korea     

Sook-Jin Kim  Joel Wainwright 《Geoforum》2010,41(5):723-733

In recent years, many geographers have examined the ways that the production of nature has changed as a result of neoliberal practices. In this paper we examine a conflict in South Korea that started when some Chinese-cabbage seeds were affected by a virus, causing crop failure. This failure came shortly after liberalization in the Korean seed industry led to foreign ownership of the firm that sold the seed. We focus in particular on the farmers’ creative political responses - and their subsequent defeat in court. Drawing on Antonio Gramsci’s insights on politics, science, and law, we examine how the seed failure came to be evaluated through scientific and legal practices. We argue that the adjudication of the truth of the seed failure through science and law reveals how socionatures are contested under prevailing hegemonic conditions. These conditions are both general and specific: although law and science are relatively hegemonic spheres of truth-production in all capitalist societies, the ways that the seeds were disputed and evaluated were distinctly Korean.  相似文献   

The role of the capture fisheries and aquaculture sectors in the Korean national economy: An input–output analysis     

《Marine Policy》2014

The aquaculture industry can meet food security needs and reduce the pressure on marine resources. The expansion of aquaculture allows the fisheries industry to restructure from hunting to farming, and thus drives the need for an analysis of the economic impacts of aquaculture industry in consideration of the interdependence between capture fisheries and aquaculture industry. This study attempts to analyze the economic impacts of two fishery sectors using input–output (I–O) analysis, with specific application to Korea. To this end, this study applies the I–O models to the Korean I–O tables generated by the Bank of Korea, paying particular attention to the two fishery sectors in Korea, considering them as exogenous, and then determining their impacts. Specifically, the production-inducing effects, employment-inducing effects, supply shortage effects, sectoral price effects, forward linkage effects, and backward linkage effects of the two fishery sectors are presented over the period 1995–2010. For example, the production-inducing effect of a KRW 1.0 change in fisheries investment is larger in the petroleum and chemical sectors than in other sectors. Moreover, the aquaculture sector has larger employment-inducing effects than the capture fisheries. Finally, the potential uses of the results of this analysis are presented from the perspective of policy instruments, and policy implications are discussed.  相似文献   

National comprehensive approaches for rebuilding fisheries in South Korea     

《Marine Policy》2014

Korea's coastal and offshore fisheries have experienced reduction in their catch in the early 2000. The amount of catch from coastal and offshore fisheries dropped from 1.7 million tons in 1986 to 1 million tons in 2004. To address such catch reduction, fish stock enhancement programs have been constantly developed and implemented. However, as fish stocks have been estimated to decrease since 2000 in spite of various management measures, the Korean Government genuinely acknowledges the necessity to enhance fisheries productivity through the recovery of depleted fish stocks. Based on such acknowledgement, a fish stock rebuilding plan (FSRP) combined with conventional fish stock enhancement programs was established in 2005. For stocks which have shown drastic decrease, a FSRP was set up and promoted. So far, 10 FSRPs have been established and operated, and plan is being made to expand them to 20 species by 2012. The result of pilot projects shows that stocks have been increasing after the introduction of FSRPs. For instance, the catch per unit effort (CPUE) of sandfish in the East Sea has increased from 0.44 in 2005 to 0.78 in 2011. Consequently, fishing income has increased by 15%. The key lessons learned during the implementation of FSRP are: the causes for the decrease of stock vary and are complicated and it is necessary to adjust and eliminate some conventional policies that could have unforeseen negative impacts on fish stocks. The FSRP-based fisheries management policy in Korea carries great significance, for it has changed the focus of policy from simply maintaining the status quo to stock recovery and it allows relevant stakeholders to get actively involved in the procedures of establishing and promoting the plan, leading to effective implementation of the plan. The current FSRP is operated with species, but if it can be gradually expanded to encompass the whole ecosystem, it will greatly contribute to more effective management and fish stock recovery for all species in offshore and coastal waters surrounding Korea.  相似文献   

地窝堡机场东南大风特征及其大气结构     

杨洪儒  王楠 《干旱气象》2014,(3):393-398

按照民航系统气象行业标准要求,结合乌鲁木齐国际机场的具体情况,给出乌鲁木齐机场东南大风的定义,并应用乌鲁木齐机场1978~2012年间逐时观测的风速风向对机场东南大风的特征进行分析,然后再引入水跃理论和Froude数,对机场东南大风发生时的大气结构做解析。结果表明:(1)1980年代与2000年代至今,为东南大风的兴盛期,1990年代为东南大风的低值期;(2)东南大风主要集中出现在春秋季,其中尤以4月出现次数最多,占总出现次数的36.4%;(3)早晨至中午期间,东南大风多发且风速较大;午后至夜间,东南大风发生次数少,且风速也相对较小;(4)东南大风的持续时间以低于5 h为主,其次为持续11 h以上的大风,而持续时间在5~11 h之间的大风出现最少;(5)对于4月和11月而言,大风发生时达坂城与本场的气压差与同时次本场的温度垂直递减率存在显著的线性关系。  相似文献   

Narooma Terrane: Implications for the construction of the outboard part of the Lachlan Orogen     

《Australian Journal of Earth Sciences》2013,60(6):1035-1041

In its type area around Narooma, the Narooma Terrane in the Lachlan Orogen comprises the Wagonga Group, which consists of the Narooma Chert overlain by the argillaceous Bogolo Formation. Conodonts indicate that the lower, largely massive (ribbon chert) part of the Narooma Chert ranges in age from mid-Late Cambrian to Darriwilian-Gisbornian (late Middle to early Late Ordovician). The upper Narooma Chert consists of shale, containing Eastonian (Late Ordovician) graptolites, interbedded with chert. Where not deformed by later faulting, the boundary between the Narooma Chert and Bogolo Formation is gradational. At map scale, the Narooma Terrane consists of a stack of imbricate thrust slices caught between two thrust faults that juxtaposed the terrane against the coeval Adaminaby Superterrane in Early Silurian time. These slices are best defined where Narooma Chert is thrust over Bogolo Formation. The soles of such slices contain multiply foliated chert. Late extensional shear bands indicate a strike-slip component to the faulting. The Narooma Terrane, with chert overlain by muddy ooze, is interpreted to be an oceanic terrane that accumulated remote from land for ～50 million years. The upward increase in the terrigenous component at the top of the Wagonga Group (shale, argillite, siltstone and sandstone of the upper Narooma Chert and Bogolo Formation) records approach of the terrane to the Australian sector of the Gondwana margin. Blocks of chert, argillite and sandstone reflect extensional/strike-slip disruption of the terrane as it approached the transform trench along the Gondwana-proto-Pacific plate boundary. Blocks of basalt and basalt breccia represent detritus from a seamount that was also entering the trench. There is no evidence that the Narooma Terrane or the adjacent Adaminaby Group formed in an accretionary prism/ subduction complex.  相似文献