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冬至初春黄海暖流的路径和起源 总被引：18，自引：0，他引：18
主要根据近几年来中韩黄海水循环动力学合作调查结果,结合有关观测资料,进一步分析了冬至初春黄海暖流的路径和起源.与以往类似研究不同的主要有两点:(1)初步探讨了黄海暖流路径的季节和年际变异,并指出这种变异与北向风的强弱密切相关;(2)通过分析济州岛西侧海域混合水的去向,进一步确认了部分混合水绕济州岛运行,并进入济州海峡这一事实.同时,初步揭示进入黄海的混合水,即黄海暖流水,含有更多的东海陆架水成分. 相似文献
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Reconstruction of evenly-spaced, regular time series from routine survey serial data was investigated for precise analysis of spatio-temporal variations in a temperate sea at mid-latitudes where the seasonality dominates the interannual variability. Considering that the annual range of sea surface temperature in the Yellow Sea and the northwestern East China Sea can be as large as 15–20 °C, temperature data collected bi-monthly in these temperate seas were used for the assessment of reconstruction methodology. The cubic spline interpolation with a sampling interval of 0.5 months reconstructed the regular time series closest to the in-situ measurements among various interpolation schemes. Also, two computation methods for the interannual anomaly were compared; the residual method that the long-term monthly means are subtracted from the monthly serial data and the filtering method that high-frequency variations are removed using a low-pass filter. In that the high-frequency variations in frequencies greater than 1 cycle per year are comparable in magnitude to the interannual variation, the residual method proves inadequate in the temperate sea. High-frequency noises can be effectively removed through the use of a proper low-pass filter with bell-shaped weights. 相似文献
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锡林郭勒草原植被生长对降水响应的滞后性研究 总被引：5，自引：3，他引：2
植被生长对气候因子变化的响应一直是全球气候变化研究的热点.NDVI作为植被生长的有效指示因子广泛的应用在植被遥感中.多数滞后性响应的研究基于月尺度或季节尺度的NDVI,容易夸大或缩小滞后效应,不利于滞后时间的确定.为了揭示降水对草原植被生长的有效作用尺度,本研究以2001年至2007年MODIS反射率数据和气象站点的降水为数据源,分析了时间间隔8天的内蒙古锡林郭勒盟草原生长季NDVI的变化特征以及NDVI与不同尺度的累积降水的相关关系.结果表明,年内生长期草原的NDVI变化呈单峰型,荒漠草原的NDVI变化没有草甸草原和典型草原明显.草原生长对降水存在明显的滞后,一般在50～60天,不同类型的草原滞后时间不同,但均无明显差异.同时,分析指出4～9月草原植被在不同时间段对降水响应的滞后时间分别为64、80、40、40、56和64天,特别是6月和7月份草原植被生长对降水变化的响应最为敏感.这为NDVI预测干旱提供参考. 相似文献
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The seasonal circulation in the southeastern Huanghai Sea has been studied with hydrographic data,which were observed in February and June 1994 and bimonthly during 1970-1990,and numerical model results.Horiwntal distributions of temperature and salinity in 1994 are quite different due to strong tidal mixing so that we need a analysis to see the real distributions of water masses.The mixing ratio analysis with the data of 1970-1990 shows the connection of the waters in the west coasts of Kotea Peninsula with warm and saline waters from the south in summer,which means northward inflows along the west coasts of Korea Peninsula in summer.With this flow,the seasonal circulations,which are deduced from the seasonal change of water mass distributions in the lower layer,are warm inflows in winter and mld outflows in summer in the central Huanghai Sea,and cold outflows in winter and warm inflows in summer along the west coasts of Korea Peninsula.The seasonally changed inflows might be the Huanghai Sea Warm Current.The monsoon winds can drive such circulations.However,summer monsoon winds are weak and irregular.As one of other possible dynamics,the variation of Kuroshio transport is numerically studied with allowing sea level fluctuations.Although it should be studied more,it possibly drives the summer circulations.The real circulations seem to be driven by both of them. 相似文献
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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
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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
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Seok Lee Heung-Jae Lie Kyu-Min Song Cheol-Ho Cho Eun-Pyo Lim 《Journal of Oceanography》2008,64(5):763-776
This study examined tidal modification and change in tidal currents caused by the construction of the Saemangeum dike, based
on field observations and a numerical model. The Saemangeum dike was completed in April 2006, enclosing an estuarine area
along the mid-western coast of South Korea. After closure of the dike, the tidal range outside the dike decreased slightly
but significantly, while the inside tidal range decreased drastically. The numerical model results show that the dike construction
has influenced tidal energy propagation and the tidal system in the Yellow Sea. The tidal current speed near the dike decreased
abruptly following closure of the dike, except in front of the sluice gates. Since completion of the dike, outflow water discharged
from the sluice gates has longer residence times due to the weakened tidal current; the change in the tidal current field
has also caused greater northward expansion of outflow water. The sluice gates release fresher water, which spreads over the
sea surface mainly by inertial momentum near the gate; this water is then gradually mixed with sea water farther from the
gate. The less saline, possibly more contaminated outflow impacts the marine environment near the Saemangeum dike. Controlling
the discharge and gate-opening timing can partially mitigate these impacts on the marine environment. 相似文献