首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Upsurges and downsurges in the Don River mouth are investigated using the observational data of the standard hydrometeorological network. The characteristics ofsurges are determined, andthe catalog of maximum annual dangerous surges is compiled for the observation points in the estuarine offshore zone and mouth reach of the Don River from the beginning of observations till 2014. The series of the maximum annual upsurges and downsurges at marine gaging stations in the Taganrog Bay are formed and statistically processed. The distribution of surges along the Taganrog Bay is analyzed. Catastrophic surges which cause adverse and severe events are identified as well as the qualitative and quaniiiaiive patterns of surge peneiraiion to the Don River mouth. The coefficients of upsurges and downsurges, the intensity of their attenuation, and water levels with the probability of 0.1, 1, and 50% at different river runoff are calculated at all gaging stations in the Don estuary for specific upsurges and downsurges. The results of test computations of surges for the specific point in the Taganrog Bay for 2013-2015 based on the numerical hydrodynamic model of the Sea of Azov are compared with observational data. The possibility was revealed of forecasting downsurges and upsurges based on synoptic conditions over the Sea of Azov with the lead time of three days using hydrodynamic models that allowed developing the prediction scheme of surge transformation calculation.  相似文献   

2.
The impact is assessed that the groundwater flow from the built-up areas on the left bank of the Don River in the Rostov oblast produces on the chemical composition and quality of surface water in the lower river reaches. It is demonstrated that the total average annual groundwater flow from the built-up areas on the left river bank is very small and equals 0.002 km3/year on average or 0.01% of the average annual water flow in the estuarine outlet. Despite the rather high degree of contamination of groundwater and the high content of principal ions, this causes the insignificant impact of groundwater runoff on water quality in the Lower Don. The average total mass of substances that annually come from the left-bank urbanized areas in the groundwater flow is about 4.9 x 103 t or 0.04% of total mass of substances transported by the Don River to the Taganrog Bay.  相似文献   

3.
At the designing of nuclear power facilities at the coastal sites the risk of their flooding caused by the combinations of adverse hydrometeorological events should be assessed with the probability of exceedance to 0.01%. According to the IAEA recommendations, the combination of statistical and deterministic methods was used to calculate the flood level of such rare occurrence. The level of flooding caused by the storm surge and reiated wind waves were computed with the probability of 0.01% for the coastal part of the Koporye Bay of the Gulf of Finland in the area of the Leningrad Nuclear Power Plant 2 (LNPP 2) construction; the results are presented. The calculations are based on the CARDINAL and SWAN software and four nested numerical models (for the Baltic Sea, the eastern part of the Gulf of Finland, the Koporye Bay, and a part of the bay in the area of LNPP). The decrease in sea-surface drag coefficient at hurricane winds is taken into account.  相似文献   

4.
The study presents the results of long-term monitoring of wind waves was carried out on the offshore fixed gas production platform in the northwestern part of the Black Sea in 1995–2011. The analysis of more than 31000 wave records provided reliable statistical characteristics of wind waves in the analyzed region. It was found that the maximum wave height reached 4.8 m in summer and 8.76 m in winter. The maximum hourly wave height exceeds significant wave height by 1.9 times in the vast majority of cases. The method of annual maxima revealed that in the Karkinit Bay the maximum wave height with the return period of 50 years is equal to 9.2 m.  相似文献   

5.
The results ofnumerical simulation of storm waves near the northeastern coast ofthe Black Sea using different wind forcing (CFSR reanalysis, GFS forecast, and WRF reanalysis and forecast) are presented. The wave modeling is based on the SWAN spectral wave model and the high-resolution unstructured grid for the Tsemes Bay. The quality estimates of wave simulation results for various wind forcing are provided by comparing the model results with the instrumental data on wind waves in the Tsemes Bay. It is shown that the forecast of the maximum wave height for some storms using the WRF wind forcing is more accurate than that based on the GFS forcing.  相似文献   

6.
The simulation the most extreme surges over the period of instrumental observations in the Taganrog Bay since 1881, the surges occurred on March 24, 2013 and September 24, 2014. The objective of the simulation is to study surge formation features and to reveal requirements for the accuracy of simulating atmospheric and oceanic circulation in the Sea of Azov. For this purpose, the Institute of Numerical Mathematics Ocean Model (INMOM) with the spatial resolution of ~4 km and ~250 m was used. The atmospheric forcing over the Black Sea region was specified using ERA-Interim reanalysis data and WRF model data with the spatial resolution of 80 and 10 km, respectively. It is shown that the quality of simulation of extreme surges in the Sea of Azov is more dependent on the quality of the input atmospheric forcing than on the spatial resolution of the ocean circulation model. The usage of WRF data as atmospheric forcing allows the more accurate simulation of extreme surges. However, the simulation of the extreme surge of 2014 overestimates, and simulations for the 2013 surge underestimate the surge level. Evidently, as the used version of INMOM does not take into account the coastal zone flooding, the maximum surge value is overestimated.  相似文献   

7.
The results of atmospheric electricity measurements are presented which were conducted at observation points of different types: at the urban point (Rostov-on-Don), at the point near the Sea of Azov (Taganrog and Primorka), and at the high-mountain point (Cheget Peak) near Elbrus. The patterns of spatiotemporal variations in electrical conductivity (concentration of light ions) of the atmospheric surface layer are revealed for different conditions. The impact of natural radioactivity and aerosol pollution on the concentration of light ions is assessed for observation points near the Taganrog Bay (the Sea of Azov). The results of the comparative analysis of urban and high-mountain data of atmospheric electricity observations are presented.  相似文献   

8.
In the summers of 2003 and 2007, eastern China suffered similar climate disasters with severe flooding in the Huaihe River valley and heat waves in the southern Yangtze River delta and South China. Using SST data and outgoing longwave radiation (OLR) data from NOAA along with reanalysis data from NCEP/NCAR, the 2002/03 and 2006/07 El Ni(n)o episodes in the central Pacific and their delayed impacts on the following early summertime climate anomalies of eastern China were analyzed. The possible physical progresses behaved as follows: Both of the moderate E1 Ni(n)o episodes matured in the central equatorial Pacific during the early winter. The zonal wind anomalies near the sea surface of the west-central equatorial Pacific excited equatorial Kelvin waves propagating eastward and affected the evolution of the E1 Ni(n)o episodes. From spring to early summer, the concurring anomalous easterly winds in the central equatorial Pacific and the end of upwelling Kelvin waves propagating eastward in the western equatorial Pacific, favored the equatorial warm water both of the SST and the subsurface temperature in the western Pacific. These conditions favored the warm state of the western equatorial Pacific in the early summer for both cases of 2003 and 2007. Due to the active convection in the western equatorial Pacific in the early summer and the weak warm SST anomalies in the tropical western Pacific from spring to early summer, the convective activities in the western Pacific warm pool showed the pattern in which the anomalous strong convection only appeared over the southern regions of the tropical western Pacific warm pool, which effects the meridional shift of the western Pacific subtropical high in the summer. The physical progress of the delayed impacts of the E1 Nifio episodes in the central equatorial Pacific and their decaying evolution on the climate anomalies in eastern China were interpreted through the key role of special pattern for the heat convection in the tropical western Pacific warm pool and the response of the western North Pacific anomalous anticyclone.  相似文献   

9.
In the summers of 2003 and 2007, eastern China suffered similar climate disasters with severe flooding in the Huaihe River valley and heat waves in the southern Yangtze River delta and South China. Using SST data and outgoing longwave radiation (OLR) data from NOAA along with reanalysis data from NCEP/NCAR, the 2002/03 and 2006/07 El Nino episodes in the central Pacific and their delayed impacts on the following early summertime climate anomalies of eastern China were analyzed. The possible physical progresses behaved as follows: Both of the moderate El Nino episodes matured in the central equatorial Pacific during the early winter. The zonal wind anomalies near the sea surface of the west-central equatorial Pacific excited equatorial Kelvin waves propagating eastward and affected the evolution of the El Ni\~no episodes. From spring to early summer, the concurring anomalous easterly winds in the central equatorial Pacific and the end of upwelling Kelvin waves propagating eastward in the western equatorial Pacific, favored the equatorial warm water both of the SST and the subsurface temperature in the western Pacific. These conditions favored the warm state of the western equatorial Pacific in the early summer for both cases of 2003 and 2007. Due to the active convection in the western equatorial Pacific in the early summer and the weak warm SST anomalies in the tropical western Pacific from spring to early summer, the convective activities in the western Pacific warm pool showed the pattern in which the anomalous strong convection only appeared over the southern regions of the tropical western Pacific warm pool, which effects the meridional shift of the western Pacific subtropical high in the summer. The physical progress of the delayed impacts of the El Ni\~no episodes in the central equatorial Pacific and their decaying evolution on the climate anomalies in eastern China were interpreted through the key role of special pattern for the heat convection in the tropical western Pacific warm pool and the response of the western North Pacific anomalous anticyclone.  相似文献   

10.
Knowledge of the likely future wind, wave and surge climate in Liverpool Bay is of importance for coastal flood defence management. We examine a 140-year time series (1960–2100) of wind and wave model projections at the WaveNet buoy location in Liverpool Bay and also of surge model projection at two ports in Liverpool Bay, namely Liverpool and Heysham. To this end we use model projections from the UK Climate Projections 09 (UKCP09) programme. We use a medium emissions scenario ensemble from the HadCM3 climate model sensitivity tests. A continental shelf model (CS3) with ~12 km resolution was used to separately simulate the waves and the surge. The models are forced by hourly wind and pressure data from the Met Office (Hadley Centre) regional climate model (RCM). Swell wave boundary conditions are generated over the full Atlantic using global climate model (GCM) winds. Analysis of significant changes in the statistics over time shows that there is little change in extreme wave and surge conditions in Liverpool Bay. Although there is a slight increase in the severity of the most extreme events, the frequency of extreme wind and wave events is slightly reduced, while the frequency of extreme surge events slightly increases over the 140-year period. From the model projections, we find that the trends in the local wind are directly reflected in the wave field within Liverpool Bay. The trends in the skew surge projections deviate slightly from those in the wind patterns.  相似文献   

11.
基于WRF3.8.1数值模式,利用FNL 1°×1°再分析资料,对山东边界层10 m、70 m、100 m等高度2017年风场进行了逐日动力降尺度模拟,使用山东122个气象站逐日平均风速,对模拟结果进行了客观评估。结果表明:WRF模式可以较好地模拟出山东逐日平均风速变化特征,但模拟值普遍大于实测值,山东不同区域平均风速模拟效果差异较大,四季误差分析结果与全年略不同;山东沿海、半岛北部丘陵、崂山、日照中部五莲山、鲁中山区各山脉等区域以及微山湖、东平湖等大型湖泊区域年和四季10 m、70 m、100 m高度平均风速、平均风功率密度较大,大汶河、大清河、泗水河、沂河及其支流、淄河、潍河等流域中上游的山区间低矮平原地带较小,但各地风能资源的差异随高度增加而明显减小。平均风速、平均风功率密度时空分布结果可为山东内陆地区分散式低风速风电场的选址、风能资源开发利用提供参考。  相似文献   

12.
Two linear methods, including the simple linear addition and linear addition by expansion, and numerical simulations were employed to estimate storm surges and associated flooding caused by Hurricane Andrew for scenarios of sea level rise (SLR) from 0.15 m to 1.05 m with an interval of 0.15 m. The interaction between storm surge and SLR is almost linear at the open Atlantic Ocean outside Biscayne Bay, with slight reduction in peak storm surge heights as sea level rises. The nonlinear interaction between storm surges and SLR is weak in Biscayne Bay, leading to small differences in peak storm surge heights estimated by three methods. Therefore, it is appropriate to estimate elevated storm surges caused by SLR in these areas by adding the SLR magnitude to storm surge heights. However, the magnitude and extent of inundation at the mainland area by Biscayne Bay estimated by numerical simulations are, respectively, 22–24 % and 16–30 % larger on average than those generated by the linear addition by expansion and the simple linear addition methods, indicating a strong nonlinear interaction between storm surge and SLR. The population and property affected by the storm surge inundation estimated by numerical simulations differ up to 50–140 % from that estimated by two linear addition methods. Therefore, it is inappropriate to estimate the exacerbated magnitude and extent of storm surge flooding and affected population and property caused by SLR by using the linear addition methods. The strong nonlinear interaction between surge flooding and SLR at a specific location occurs at the initial stage of SLR when the water depth under an elevated sea level is less than 0.7 m, while the interaction becomes linear as the depth exceeds 0.7 m.  相似文献   

13.
通过SODA再分析资料和AVISO观测资料研究了斯里兰卡穹顶区(SLD)的迁移和消散机制.斯里兰卡穹顶区是孟加拉湾西南部的一个气旋涡旋,主要出现在西南季风(5-9月)期间,与西南季风海流侵入孟加拉湾同时存在.正风应力旋度引起的Ekman抽吸是形成SLD的主要原因.回归分析结果表明SLD区域的风应力旋度与Ekman抽吸存在较强的正相关(r2=0.93,p>0.5).此外,结果表明SLD在发展过程中的移动主要受正风应力旋度移动的影响,SLD的消减与该正风应力旋度减弱和西传的暖Rossby波有关,而冷Rossby波的传播有益于SLD的发展.在SLD消减时期,孟加拉湾涡旋(BBD)独立发展并进一步与SLD融合,回归分析发现BBD区域的Ekman抽吸与当地风应力旋度的关系密切(r2=0.76,p>0.5),这表明了BBD在形成阶段由局地的风应力主导.9月之后,风应力旋度减弱,BBD和SLD开始了合并过程.动力方面,EKE分析显示SLD衰退的同时,BBD的EKE大幅增加;热力方面,10-11月时,由Ekman抽吸引起的SLD和BBD次表层冷水汇合,清晰地表明了二者之间的热动力学联系.  相似文献   

14.
王东勇  张娇  朱红芳  郑媛媛 《气象》2008,34(8):63-69
利用NCEP 1998-2007年分析资料,分析了2007年、2005年和2003年3个淮河大洪水年7月上旬逐日各层的位势高度、温度、水汽和风场等资料.分析结果表明:这3个洪水年和近10年平均场的大尺度环流背景、高低空急流、水汽输送特征等存在显著差异.东亚夏季风异常是这3年淮河流域洪涝出现的主要原因.同时,这3年西北太平洋副热带高压均较历史同期偏强,西伸脊点偏西;华北南部到黄淮距平风场上有较常年明显的偏北气流,副热带高压西北侧850hPa低空急流较常年平均偏强6m·s-1以上,南北两支气流交汇区正好位于淮河流域;在200hPa上淮河流域处于异常的高空急流入口南侧或受较常年偏强的反气旋环流控制之下;从整层水汽通量距平分析,南海是这3个淮河洪涝年的主要水汽源地.  相似文献   

15.
贺海晏 《大气科学》1993,17(5):532-539
本文利用常规探测资料,分析了1983年3月25日发生在珠江三角洲地区的一次强对流天气过程背景流场的几个重要特征,如高空急流的结构与变化、辐散风场及与之相联系的背景次级环流、风场垂直切变和水平切变等.  相似文献   

16.
利用第二次青藏高原(下称高原)综合科考"地-气相互作用与气候效应"立体综合加强期观测试验2019年5月、7月和10月珠峰、林芝、那曲和狮泉河站点的探空资料及ERA5再分析资料.探讨在西风南支与高原季风不同风场控制下高原大气边界层结构特征及其与感热潜热通量的关系.结果表明:西风南支风场下各站点大气边界层高度较高原夏季风风...  相似文献   

17.
利用 1980-1997年 6-8月 NECP/NCAR月平均资料,计算了大气热源和水汽汇,研究了我国长江中下游夏季严重旱涝时期大气环流以及大气热源和水汽汇的异常特征,主要结果如下: 在对流层中下层,来自于孟加拉湾和南海的南风异常和长江流域以北的北风异常在长江中下游辐合。这两股异常气流分别与西太平洋上反气旋异常系统(中心位于22°N,140°E)和气旋异常系统(中心位于日本海)有关。在对流层高层,反气旋异常系统中心位于23°N,105°E,气旋异常系统中心位于朝鲜,两异常系统之间的西北异常气流在长江中下游辐散。而在印度西南季风区为偏东风异常,表示西南季风的减弱; 长江中下游严重干旱时,在对流层中下层,长江以北南风异常和长江以南北风异常从长江流域辐散,在以东的洋面上形成东风异常气流。这两股异常气流分别与酉太平洋上气旋异常系统(中心位于23°N,135°E)和西北太平洋上反气旋异常系统有关。在对流层高层,气旋异常系统中心位于南海,反气旋异常系统中心位于日本海,两异常系统之间的偏东异常气流在长江中下游辐合。 热源异常的最主要特征是长江中下游严重洪涝时从西太平洋到南海热源异常为负,表示热源偏弱;正热源异常位于长江流域。而长江中下游严重干旱时热源异常正好相反。垂直  相似文献   

18.
长江流域不同区域暴雨发生机理的比较研究   总被引:4,自引:3,他引:4  
对发生于1998年7月21日长江流域不同区域同时次的两个暴雨个例发生的机理进行了比较研究。结果表明:长江上游的贵州思南暴雨受西南涡、低空急流及南亚高压的影响,雨区位于低空急流的左中侧,水汽主要来源于孟加拉湾。而长江中游的武汉暴雨不受西南涡的影响,主要是边界层偏南风急流、低空西风急流、高空西风急流三者上下耦合的结果,其水汽来源主要是南海,暴雨区上空低层为非热成风的对流不稳定,高层为非热成风的对称不稳定。  相似文献   

19.
Aerodynamic roughness of the sea surface at high winds   总被引:2,自引:0,他引:2  
The role of the surface roughness in the formation of the aerodynamic friction of the water surface at high wind speeds is investigated. The study is based on a wind-over-waves coupling theory. In this theory waves provide the surface friction velocity through the form drag, while the energy input from the wind to waves depends on the friction velocity and the wind speed. The wind-over-waves coupling model is extended to high wind speeds taking into account the effect of sheltering of the short wind waves by the air-flow separation from breaking crests of longer waves. It is suggested that the momentum and energy flux from the wind to short waves locally vanishes if they are trapped into the separation bubble of breaking longer waves. At short fetches, typical for laboratory conditions, and strong winds the steep dominant wind waves break frequently and provide the major part of the total form drag through the air-flow separation from breaking crests, and the effect of short waves on the sea drag is suppressed. In this case the dependence of the drag coefficient on the wind speed is much weaker than would be expected from the standard parameterization of the roughness parameter through the Charnock relation. At long fetches, typical for the field, waves in the spectral peak break rarely and their contribution to the air-flow separation is weak. In this case the surface form drag is determined predominantly by the air-flow separation from breaking of the equilibrium range waves. As found at high wind speeds up to 60 m s−1 the modelled aerodynamic roughness is consistent with the Charnock relation, i.e. there is no saturation of the sea drag. Unlike the aerodynamic roughness, the geometrical surface roughness (height of short waves) could be saturated or even suppressed when the wind speed exceeds 30 m s−1.  相似文献   

20.
Large amplitude, isolated, wave-like phenomena have been observed in the lowest 40 m of the strongly stably stratified atmospheric boundary layer overlying a coastal Antarctic ice shelf. The waves only occur when prevailing wind speeds are low. They always propagate from over the land, with phase speeds exceeding the local mean wind speed. They have wavelengths of the order of 200 m. Several examples are described and a summary of the statistical properties of these waves events is presented.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号