Annual and Seasonal Variations of the Sea Surface Heat Fluxes in the East Asian Marginal Seas     

Jungyul Na  Jangwon Seo  Heung-Jae Lie 《Journal of Oceanography》1999,55(2):257-270

Based on the twice-daily marine atmospheric variables which were derived mostly from the weather maps for 18 years period from 1978 to 1995, the surface heat flux over the East Asian marginal seas was calculated at 0.5°×0.5° grid points twice a day. The annual mean distribution of the net heat flux shows that the maximum heat loss occurs in the central part of the Yellow Sea, along the Kuroshio axis and along the west coast of the northern Japanese islands. The area off Vladivostok turned out to be a heat-losing region, however, on the average, the amount of heat loss is minimum over the study area and the estuary of the Yangtze River also appears as a region of the minimum heat loss. The seasonal variations of heat flux show that the period of heat gain is longest in the Yellow Sea, and the maximum heat gain occurs in June. The maximum heat loss occurs in January over the study area, except the Yellow Sea where the heat loss is maximum in December. The annual mean value of the net heat flux in the East/Japan Sea is −108 W/m² which is about twice the value of Hirose et al. (1996) or about 30% higher than Kato and Asai (1983). For the Yellow Sea, it is about −89 W/m² and it becomes −75 W/m² in the East China Sea. This increase in values of the net heat flux comes mostly from the turbulent fluxes which are strongly dependent on the wind speed, which fluctuates largely during the winter season. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Effect of urbanization on runoff characteristics of the On-Cheon Stream watershed in Pusan,Korea     

In Shik Kang  Jun Il Park  Vijay P. Singh 《水文研究》1998,12(2):351-363

This study investigated the effect of urbanization on runoff from the On-Cheon Stream watershed in Pusan, Korea. This watershed has been experiencing considerable urbanization since the 1960s. There are two gauging stations in the watershed. For one of the stations there are recent flow data and for the other flow data were observed in the past. A linear reservoir model was chosen and runoff was analysed for several flood events. The linear reservoir model has been found to generate flood hydrographs accurately for both gauging stations, and its applicability to the study area has also been established. Using two methods of computing effective rainfall or rainfall excess (ϕ-index and constant percentage method), the results of runoff analyses were investigated. The ϕ-index method yielded better results than the constant percentage method. A comparison of hydrographs observed in the past with the simulation results at the Ie-Sup bridge site revealed that the peak discharge increased and the mean lag time of the study area decreased owing to urbanization over the past two decades. It is also possible to evaluate the effect of urbanization quantitatively. © 1998 John Wiley & Sons, Ltd.  相似文献   

Ecological–Microbiological Studies of Lake Beloe in Winter and Spring with the Use of Innovation Test-Systems     

Mosharova  I. V.  Il’inskii  V. V.  Mosharov  S. A.  Akulova  A. Yu. 《Water Resources》2019,46(6):959-965

Water Resources - Chlorophyll a concentration, the total abundance of bacteria, the number of bacterial cells with active metabolism, and the abundance of saprotrophic bacteria were studied in the...  相似文献   

Limit state analysis of earthen slopes using dual continuum/FEM approaches     

Colby C. Swan  Young-Kyo Seo 《国际地质力学数值与分析法杂志》1999,23(12):1359-1371

A framework alternative to that of classical slope stability analysis is developed, wherein the soil mass is treated as a continuum and in-situ soil stresses and strengths are computed accurately using inelastic finite element methods with general constitutive models. Within this framework, two alternative methods of stability analysis are presented. In the first, the strength characteristics of the soil mass are held constant, and the gravitational loading on the slope system is increased until failure is initiated by well-defined mechanisms. In the second approach, the gravity loading on the slope system is held constant, while the strength parameters of the soil mass are gradually decreased until well-defined failure mechanisms develop. Details on applying both of the proposed methods, and comparisons of their characteristics on a number of solved example problems are presented. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

State of heterotrophic bacterioplankton of Yenisei estuary and the zone of Ob–Yenisei discharge in autumn in relation with environmental factors     

I. V. Mosharova  V. V. Il’inskii  S. A. Mosharov 《Water Resources》2016,43(2):341-352

In September 2011, variations of the total abundance of bacteria were studied, including, for the first time, the abundance of bacteria with intact membranes and active electron transport chains, as well as chlorophyll a concentrations and some hydrological and hydrochemical characteristics of water in Yenisei estuary and the zone of Ob–Yenisei river discharge. The study found abundant, viable, and actively functioning bacterioplankton to exist in the region. The absolute values of all microbiological characteristics were found to decrease with the distance from the freshened waters of Yenisei estuary toward the seawater of the Ob–Yenisei river discharge, while the percentage of bacteria with intact membranes and actively functioning microorganisms in bacterioplankton increased in the same direction. Positive correlations were found to exist between the values of all examined microbiological characteristics and the concentration in water of chlorophyll a, silicium, organic nitrogen, and oxygen, as well as water temperature. The same biological characteristics showed negative correlations with water salinity and phosphates. The spatial distribution of bacteria in the examined water body was supposed to be due mostly to the intensity of hydrodynamic processes, rather than the biogenic matter content of water.  相似文献   

Multifractal properties of the peak flow distribution on stochastic drainage networks   总被引：1，自引：1，他引：0  

Yongwon Seo  Arthur R. Schmidt  Boosik Kang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(5):1157-1165

In this paper, we examined the peak flow distribution on a realization of networks obtained with stochastic network models. Three network models including the uniform model, the Scheidegger model, and the Gibbsian model were utilized to generate networks. The network efficiency in terms of drainage time is highest on the Scheidegger model, whereas it is lowest on the uniform model. The Gibbsian model covers both depending on the parameter value of β. The magnitude of the peak flow at the outlet itself is higher on the Scheidegger model compared to the uniform model. However, the results indicate that the maximum peak flows can be observed not just at the outlet but also other parts of the mainstream. The results show that the peak flow distribution on each stochastic model has a common multifractal spectrum. The minimum value of α, which is obtained in the limit of a sufficiently large q, is equal to the fractal dimension of a single river. The multifractal properties clearly show the difference among three stochastic network models and how they are related. Moreover, the results imply that the multifractal properties can be utilized to estimate the value of β for a given drainage network.  相似文献   

Sensitivity of MM5 and WRF mesoscale model predictions of surface winds in a typhoon to planetary boundary layer parameterizations   总被引：2，自引：1，他引：1  

Ji Hye Kwun  You-Keun Kim  Jang-Won Seo  Ju Hee Jeong  Sung Hyup You 《Natural Hazards》2009,51(1):63-77

Sea surface winds and coastal winds, which have a significant influence on the ocean environment, are very difficult to predict. Although most planetary boundary layer (PBL) parameterizations have demonstrated the capability to represent many meteorological phenomena, little attention has been paid to the precise prediction of winds at the lowest PBL level. In this study, the ability to simulate sea winds of two widely used mesoscale models, fifth-generation mesoscale model (MM5) and weather research and forecasting model (WRF), were compared. In addition, PBL sensitivity experiments were performed using Medium-Range Forecasts (MRF), Eta, Blackadar, Yonsei University (YSU), and Mellor–Yamada–Janjic (MYJ) during Typhoon Ewiniar in 2006 to investigate the optimal PBL parameterizations for predicting sea winds accurately. The horizontal distributions of winds were analyzed to discover the spatial features. The time-series analysis of wind speed from five sensitivity experimental cases was compared by correlation analysis with surface observations. For the verification of sea surface winds, QuikSCAT satellite 10-m daily mean wind data were used in root-mean-square error (RMSE) and bias error (BE) analysis. The MRF PBL using MM5 produced relatively smaller wind speeds, whereas YSU and MYJ using WRF produced relatively greater wind speeds. The hourly surface observations revealed increasingly strong winds after 0300 UTC, July 10, with most of the experiments reproducing observations reliably. YSU and MYJ using WRF showed the best agreements with observations. However, MRF using MM5 demonstrated underestimated winds. The conclusions from the correlation analysis and the RMSE and BE analysis were compatible with the above-mentioned results. However, some shortcomings were identified in the improvements of wind prediction. The data assimilation of topographical data and asynoptic observations along coast lines and satellite data in sparsely observed ocean areas should make it possible to improve the accuracy of sea surface wind predictions.  相似文献   

Spatial distribution of sister species of vesicomyid bivalves Calyptogena okutanii and Calyptogena soyoae along an environmental gradient in chemosynthetic biological communities in Japan     

Hiromi Watanabe  Eriko Seo  Yoshimi Takahashi  Takao Yoshida  Shigeaki Kojima  Katsunori Fujikura  Hiroshi Miyake 《Journal of Oceanography》2013,69(1):129-134

Vesicomyid bivalves have a substantial biomass in deep-sea chemosynthetic biological communities in the Pacific. Using a novel multiplex-PCR (mPCR) method to identify the co-occurring vesicomyids in Sagami Bay, we analyzed the distribution of Calyptogena okutanii and Calyptogena soyoae along environmental gradients. All the known distributions of C. okutanii indicated the different preferences in salinity and temperature to those of C. soyoae, and in Sagami Bay, depth seemed to be an important environmental factor, too. Although the concentration of hydrogen sulfide in sediment was not examined, our results showed that the distributions of these two Calyptogena clams were affected by salinity and temperature.  相似文献   

Role of piles in mitigating the movement of pipes in soft grounds during embankment loading     

Won Pyo Hong  Jae Hong Kim 《Marine Georesources & Geotechnology》2013,31(9):1019-1031

Abstract

Pipes buried in soft ground can be damaged due to the vertical and lateral movement of the ground during the construction of the embankment. To investigate such a movement of the soft ground, full-scale tests using embankment piles and stabilizing piles were conducted for 70?days. A pile-supported embankment has been used to reduce the deformation of soft ground by transferring the embankment load through piles to the firm layer below the soft ground, whereas stabilizing piles have been employed to resist the lateral earth pressure that is induced in soft ground by embankment loads. The Coupling Area (CA), which was defined as the quantitative index to determine the resistance effect of both settlement and lateral flow of the soft ground when the embankment was reinforced, is adapted. The analysis results of the CA indicate that the piled embankment was more effective for preventing the damage to buried pipe installed near the embankment, while the stabilizing piles had almost the same effect as the piled embankment when the pipe was buried far away from the embankment.  相似文献   

Evaluation of Liquefaction Potential Index Along Western Coast of South Korea Using SPT and CPT     

Min-Woo Seo  Scott M. Olson  Myoung-Hak Oh 《Marine Georesources & Geotechnology》2013,31(3):234-260

For South Korea, liquefaction potential along the western coast has not been widely assessed because South Korea is considered to be a low seismic hazard. However, recent earthquake events and historical records indicate that the seismic hazard of South Korea should not be ignored. Moreover, as artificial fills are extensively used along the western coast for development, liquefaction evaluation of the soils in this area is necessary. In this paper, we present: (1) the seismic characteristics of the study area; (2) procedures for evaluating liquefaction potential, focusing on the liquefaction potential index (LPI) approach; and (3) LPI distributions at several representative locations along the western coast of South Korea under various seismic scenarios. The liquefaction potential index represents the liquefaction potential over the upper 20 m of a boring or sounding. Using cone penetration test (CPT) and standard penetration test (SPT) data from two coastal sites, we compare and discuss CPT-based and SPT-based LPI values, particularly values computed in nonplastic, silt-rich soils. In these soils, it appears that the CPT yields lower liquefaction resistance, resulting in large LPI values. Finally, discussion and suggestions are provided for CPT- and SPT-based liquefaction assessment of low plasticity and high fines content soils.  相似文献