Forecasting environmental contamination development in the coastal and water area of the Russian far east under the effect of the radiation factor and industrial anthropogenic load under conditions of catastrophes

Studies of seasonal variability (including the winter season) of the main hydrodynamic, sedimentation, physicochemical and other characteristics of the Chazhma Bay of the Sea of Japan, in the zone of the atomic submarine K-431 nuclear accident of 1985 that influence the radioecological state of the environment was carried out. The substance fluxes required for estimating radionuclide balance are defined based on the expedition survey of radioactivity of bottom sediments, sea water, and suspension in the epicenter of the accident and over the water area of the bay together with hydrophysical, sedimentation, and meteorological observations. Modern trace methods and 3D prognostic modeling of interaction of natural and anthropogenic processes of evolution of radioactive contamination of the bottom sediments in the zone of the atomic submarine accident are used; a new approach to estimating the maximum contamination of the marine environment is proposed.     

Bottom sediments and their role in surface water pollution with mercury (with a special reference to the Northern Dvina River Mouth and the Dvina Bay of the White Sea)

Mercury content in bottom estuarine sediments of the Northern Dvina River and the Dvina Bay of the White Sea is studied. Major regularities of the behavior of the metal and its compounds in bottom sediments of the water area are defined. The role of lithological composition, pH and Eh of the environment, the presence of hydrogen sulfide for determining the content and forms of the mercury presence in the bottom sediments of the region are studied. The sediments related to technogenic formations are specified. The paths and forms of mercury coming from bottom sediments to the near-bottom water level are detected, and the methylmercury content in the sediments is calculated.     

Wintertime winds in and around the Ulaanbaatar metropolitan area in the presence of a temperature inversion

Temperature inversions are frequently observed in mountainous urban areas and can cause severe air pollution problems especially in wintertime. This study investigates wintertime winds in and around the Ulaanbaatar, the capital of Mongolia, metropolitan area in the presence of a temperature inversion using the Weather Research and Forecasting (WRF) model coupled with the Seoul National University Urban Canopy Model (SNUUCM). Ulaanbaatar is located in complex terrain and in a nearly east-west-oriented valley. A wintertime scenario with clear skies, weak synoptic winds, and a temperature inversion under the influence of a Siberian high-pressure system is selected. Local winds are weak in the presence of the temperature inversion. In the daytime, weak mountain upslope winds develop, up-valley winds appear to be stronger in the urban area than in the surrounding areas, and channeling winds are produced in the main valley. The bottom of the temperature inversion layer rises up in the urban area, and winds below the bottom of the temperature inversion layer strengthen. In the nighttime, mountain downslope winds and down-valley winds develop. Urban effects in the presence of the temperature inversion are examined by comparing the results of simulations with and without the city. It is shown that in the daytime the urban area acts to elevate the bottom of the temperature inversion layer and weaken the strength of the temperature inversion layer. Winds east of the city weaken in the afternoon and down-valley winds develop later in the simulation with the city.     

Monitoring of polycyclic aromatic hydrocarbons in the Lake Baikal basin in the areas of intensive anthropogenic impact

Presented are the results of studying the content of polycyclic aromatic hydrocarbons and benz(a)pyrene in the lake water, in sewage waters of the enterprise, and in the upper 2-cm layer of bottom sediments in the area of the sewage discharge of Baikal Pulp and Paper Mill (BPPM), in bottom sediments in the north of Lake Baikal in the area of the Baikal-Amur Railroad, and in the channel and delta front of the Selenga River. The results were obtained at Hydrochemical Institute in 1981?C1989. The different content of benz[a]pyrene was determined for the first time in bottom sediments (sands and silts) for the bottom area of polygons in the mentioned regions. An intensive pollution exceeding significantly the normalized parameters for the benz[a]pyrene in bottom sediments is registered in the BPPM area only and its content in other areas does not exceed the background values on the whole.     

Conditions of the formation and runoff of shelf waters in different water areas of the Arctic and Antarctic

The comparative analysis of hydrometeorological and topographic conditions of the formation and runoff of dense shelf waters on the shelves and continental slopes in different water areas of the Arctic and Antarctic demonstrates that they are similar in many aspects but there are some differences as well. In the Antarctic, these conditions are more favorable. The thermohaline conditions of the formation and runoff of shelf waters in the Arctic and Antarctic are also similar. The similarity of different conditions enables to construct the adaptive physical model of the shelf and slope cascading of shelf waters generalized for different polar water areas. It is based on the analysis of historical and present-day in situ data in the areas of margins of shelves and slopes in the Arctic and Antarctic, observations in the areas of flaw polynyas, and passing ice and meteorological observations, as well as on taking account of some general results of laboratory and theoretical investigations of the dense liquid runoff along the inclined bottom.     

Arsenic content in water and bottom sediments in the areas of chemical weapon dumps in the Bornholm basin of the Baltic Sea

Data are considered on samples taken during the 2006–2008 expeditions from the water and bottom sediments in the areas where chemical weapon was dumped in the Bornholm basin. Arsenic concentration is detected with the X-ray fluorescence analysis and inversion voltammetry. Results are under consideration of the enhanced arsenic content and their relation to arsenic-bearing toxic agents. It is pointed out that arsenic contamination is local in character and at present is of no serious hazard to the natural environment.     

北京地区城市暴雨积涝灾害风险预评估

该文提出自下而上的城市暴雨积涝灾害风险定量评估方法,即在三级评估指标体系下,由下级指标综合核算上级指标系数。在第2级指标计算中,风险区划的危险性指数由历史降水量资料推算得出,风险预警则用实况及预报降水量来计算致灾因子危险性指数;暴雨敏感性指数综合叠加地形、不透水地表因子及河网密度得出;暴雨积涝的风险暴露因子侧重地均人口密度、地均GDP及重点防汛指标等因子,着重于城市地区人口、经济、防汛重点目标的暴露程度。然后在危险性、敏感性及暴露性指数的基础上叠加得出积涝风险指数。通过对比发现,得到的风险区划结果与2004—2008年北京地区暴雨积涝的历史灾情基本吻合。最后,选用北京2011年“6.23”暴雨作风险预警的实例应用检验及分析,结果表明:采用自下而上的快速风险评估结果与积涝的实际发生情况较为接近,无论是风险变化趋势还是风险区域分布情况均与当天的积涝发生情况基本吻合。即该方法能较为准确、快捷地圈定城市地区各级风险区域,能较好地满足风险评估、区划及风险预警的要求。     

Accumulation Dynamics of Polycyclic Aromatic Hydrocarbons in Lake Baikal Bottom Biocenoses Assessed from Biogeochemical Monitoring Data

The results of long-term biogeochemical monitoring of Lake Baikal are presented. The accumulation is studied of polycyclic aromatic hydrocarbons (PAHs) in bottom sediments and macrozoobenthos that were synchronously sampled at the same stations. The stations are located in the areas where anthropogenic impact on the lake is high: in the area of the former Baikal Pulp and Paper Mill (BPPM), in the footprint of the BAM railway in the north of the lake and in the Selenga River delta front as well as in the zones of coastal fouling in the area of BPPM. It is found that variations in the concentration of PAHs in macrozoobenthos do not directly depend on those in the sediments. It is revealed that the maximum concentration of benzo[a]pyrene in the area of the former BPPM is almost by eight times higher than in the other areas of the lake; shallow-water macrophytes accumulate more polyarenes than deep-water macrozoobenthos.     

On the effects of vertical eddy viscosity on rossby and eady waves in the ocean

The effects of vertical eddy viscosity on simple mesoscale waves in the ocean are studied. The decay of Rossby waves is investigated by one-dimensional depth-dependent linear stability problems which are derived for the interior non-viscous or viscous quasigeostrophic flow using parameterizations of the top and bottom boundary layers corresponding to Ekman suction, no-stress and bottom-stress boundary conditions.The non-slip condition at the bottom yielding an O(E_v^1/2)-Ekman layer causes very short damping times for the 0th Rossby mode. This suggests that this boundary condition is not suitable for mesoscale wave studies, because a Rossby wave fit for the MODE eddy can be done satisfactorily without any damping. Reasonable results for damping times of Rossby waves are obtained by prescribing the bottom stress, resulting from the constant-stress layer at the bottom, and the free-slip condition at the surface. The growth rates of Eady waves are reexamined using this bottom-stress condition.Vertical viscosity in the interior of the ocean, e.g. internal wave induced viscosity, may have a significant influence on the dynamics of the mesoscale motions, comparable to that of the boundary layers in some cases. The results are compatible with the sparse observations available.     

Quasi-geostrophic modeling of mixed instabilities in the Gulf Stream near 73°W

The characteristics of the unstable normal modes of fluctuation of an eastward-flowing jet over a weak bottom slope are examined with a linear, quasi-geostrophic, continuously stratified, mixed-instability model utilizing basic-state fields determined from observations of the velocity and temperature structure of the Gulf Stream near 73d°W. Comparison of the model results with Gulf Stream path observations based on inverted echo sounder measurements in the area between 74°W and 70°W shows that the model can predict several of the observed features of Gulf Stream meanders: (a) two dispersion regimes, one with fast and one with slow changes in phase speed with meander wavelength; (b) the wavelengths λ associated with two growth maxima, a primary maximum at λ 270 km and a secondary maximum at λ 180 km.The energy conversion rates, when integrated over the model cross-sectional domain, change from predominantly baroclinic for fluctuations with λ < 370 km, to predominantly barotropic for λ > 370 km. The eddy pressure field is surface intensified in the upper 1000 m; a secondary intensification due to bottom topography occurs for the shorter wavelength (λ 180 km) fluctuations near the bottom at the area where the basic state jet extends to the bottom.In the absence of bottom slope, the phase speeds decrease and the growth rates increase relative to the sloped bottom case for all fluctuations with λ > 200 km; consistent with observations showing Gulf Stream meanders to slow down as they propagate through areas of relaxing bottom slope. Fluctuations with λ > 1000 km propagate upstream with phase speed of the order of −5 km day⁻¹. The energy conversion rates, integrated over the model cross-sectional area, are predominantly baroclinic for all wavelengths.     

黄海典型气旋与反气旋式海洋涡旋特征及影响机制模拟研究

为探讨黄海海洋涡旋的三维结构特征、能量输送与转换及影响机制,对黄海海域典型台风海洋气旋与近海海湾反气旋式涡旋个例进行数值模拟和时空诊断分析。采用FVCOM(Finite Volume Community Ocean Model)区域海洋数值模式精细化描述台风海洋涡旋与近海海洋中小尺度涡旋系统。对涡旋能量传输特征模拟显示,气旋式和反气旋式海洋涡旋中,非对称强流区动能能量下传比涡旋中心部位的强度更强,维持时间更长,下传深度更深。反气旋式海洋涡旋因Ekman流动形成的向中心辐合作用,造成此类差异更显著。气旋涡的动能主要来源于台风的近海面风应力动能和海洋涡旋有效位能的转换,反气旋涡旋区域风动力偏弱,其动能强度维持在低位,其涡旋增强伴随着有效位能的增加。环境因子影响机制从风浪,底摩擦和地形三方面讨论。结果显示:耦合波浪模块后,台风强风应力和风浪的综合作用扩大台风海洋涡旋尺度,并增强涡旋环流强度,同时对相邻的反气旋涡有压缩和减弱作用。风浪效应对台风海洋涡旋有正贡献。强台风过程表层环流响应台风应力而浅水地形和底摩擦强烈影响涡旋下层,造成台风海洋涡旋结构在垂直方向上偏移,并影响到下层环流速度减小,流向与表层相反。在海洋气旋涡和反气旋涡的显著辐散区,其混合层下方有温盐要素的涌升对应,辐合区有温盐要素的下沉对应;同时海底地形的升降也造成温盐强迫上升与下降,其强度与地形起伏尺度成正比,较环流系统作用更强。     

Water Circulation Off the Northeastern Coast of Sakhalin during the Passage of Three Types of Deep Cyclones over the Sea of Okhotsk

Based on the numerical simulation of water circulation in the Sea of Okhotsk in 1986 to 2015, the impact of deep cyclones on the circulation off the northeastern coast of Sakhalin is studied. The circulation in the Sea of Okhotsk is simulated with the COSMO-Ru-INMOM-CICE model configuration, where the COSMO-Ru and INMOM resolve explicitly the mesoscale atmosphere and ocean dynamics and the CICE resolves the ice cover evolution. The extreme atmospheric events associated with the intensive cyclone activity over the Sea of Okhotsk during the cold season are classified. It is found that high velocity is typical of the cyclones coming to the sea from Sakhalin, and wind speed on the periphery is higher for the cyclones coming to the Sea of Okhotsk from the south and southwest. The analysis of water circulation response off the northeastern coast of Sakhalin demonstrates that the meridional current velocity on the shelf increased by several times from the sea surface to the bottom for all types of cyclones. On the edge of the shelf, southern currents intensified in the surface and bottom layers during the passage of cyclones and at the intermediate depths during the passage of fronts. On the continental slope, southern currents intensified in the surface, intermediate, and bottom layers depending on the type of extreme events.

     

Influence of Global Climate Changes in Past Centuries on the Chemical Composition of Bottom Sediments in the Chukchi Sea

The sedimentary cores from the southern and northern parts of the Chukchi Sea illustrate the influence of climate and environmental conditions on the chemical composition of bottom sediments accumulated at present and in the recent 500 years. The low concentration of biogenic (Ca, Br, Sr) and some redox-sensitive (Fe, Mn, Zn) elements is typical of the recent sediments accumulated in the areas with permanent ice cover and of the sediments accumulated during cold periods (Little Ice Age and especially the Maunder Minimum). The possibility is revealed of identifying cyclic changes in environmental conditions including sea ice extent in the concrete Arctic areas. This may be used to detail the regional forecast of future changes.     

2002年夏季河南省冰雹回波特征

利用2002年夏季雷达观测到的雹云回波资料，分析了雹云在成熟阶段时在雷达回波上表现出的不同特征及对应的冰雹落区，结果表明，“V”形缺口回波顶端、指状回波及其指根处、钩状回波钩部对应地面冰雹落区。     

A model of the wind-driven circulation in Lake Baikal

A numerical model based on the Navier–Stokes equations is used to simulate the circulation produced by a strong wind in a cross-section of Lake Baikal. Temperature distributions have been obtained for different stages of the spring warming of the lake, using available measurements and simulating the faster warming of the near-shore areas in accordance with the local stability conditions. These have been used as initial conditions for the prediction of the wind-driven circulation. The results presented suggest that buoyancy forces have little impact on the magnitude of vertical currents descending towards the bottom of the lake, but the action of buoyancy forces could initiate additional motions that have been found to generate strong vertical currents far from the shores. Furthermore, there appears to be evidence in our data of local acceleration linked to changes in the bottom topography of the section.     

The POSEIDON Nearshore Wave Model and its Application to the Prediction of the Wave Conditions in the Nearshore/Coastal Region of the Greek Seas

In the present work, the Poseidon Nearshore Wave Model (PNWM) developed in the framework of the POSEIDON project 1 , and its application to the prediction of the wave conditions in nearshore/coastal regions of Greek seas is presented. The PNWM is based on a one-way energy coupling between a third-generation, phase-averaged, nearshore wave model and a local phase-resolving model, nested in the first model. The local wave model is supported by the consistent coupled-mode theory, based on an enhanced local-mode representation of the wave velocity field, which except for the propagating and the evanescent modes includes an additional mode, permitting the exact satisfaction of the sloping-bottom boundary condition, even in areas with locally steep bottom slope and large curvature. Thus, three-dimensional diffraction effects are fully treated in the local nested area. Numerical results are presented demonstrating the application of the PNWM to nearshore and coastal sites of the Greek seas.     

乌蒙山东侧冰雹云形成机制及催化机理研究

【目的】解决山区冰雹预报及防控技术难题,深入认识复杂山地环境下冰雹灾害天气形成机理。【方法】采用多源观测资料与数值模拟结合,使用乌蒙山东侧雹源地（贵州冰雹防控外场试验基地）布设的垂直观测系统加密观测资料及ERA5高分辨率再分析资料,结合云贵高原下垫面资料,研究了贵州西部冰雹源地的地形影响、环境条件、深对流触发动力因子、云微物理形成和人工防雹催化等方面的特征和机制。【结果】建立了贵州西部冰雹观测数据集;探讨了冰雹源地地形位涡的存在性、演变以及它的产生机制; 分析了雹源地上空不稳定层结条件下深对流触发的动力学特征,发现存在三个加减速关键区：云底加速、云顶加速、下沉减速,上升气流、下沉气流和水汽条件等因素对冰雹增长具有重要影响;对贵州西部一次冰雹过程进行了催化模拟研究,结果表明不同催化高度、催化剂量和催化时间的催化效果存在显著差异,给出了最佳的催化方案。【结论】研究为理解和预测雹暴等深对流的发生发展提供了重要的理论依据,也为实际的防雹作业提供了科学依据。     

Physical experiments to investigate the effects of street bottom heating and inflow turbulence on urban street-canyon flow

The effects of street bottom heating and inflow turbulence on urban street-canyon flow are experimentally investigated using a circulating water channel. Three experiments are carried out for a street canyon with a street aspect ratio of 1. Results from each experiment with bottom heating or inflow turbulence are compared with those without bottom heating and appreciable inflow turbulence. It is demonstrated that street bottom heating or inflow turbulence increases the intensity of the canyon vortex. A possible explanation on how street bottom heating or inflow turbulence intensifies the canyon vortex is given from a fluid dynamical viewpoint.     

A study on the nonlinear stability of fronts in the ocean on a sloping continental shelf

1.IntroductionArnol'd(1965,1969)variationalprincipleandapriorestimatemethodisessentiallyageneralizationofLyapunovstabilitymethodforfinite--dimensionaldynamicalsystemsininfinite--dimensionalones,andhestudiedthenonlinearstabilityof2--dimensionalincompressibleidealfluidmotionbyuseofthismethod,andestablishedtwotheoremswhichareArnol,d'sfirsttheoremandArnol'd'ssecondtheorem.Eversincethe1980's,manyscientistshavebeenworkingonthissubject,Holmetal.(1985);MclntyreandShepherd(1987);Zeng(1989);Muetal.(1…