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1.
Considered are the peculiarities of fast ice formation in the Antarctic coastal waters. It is noted that the fine-crystalline ice with the chaotic orientation of crystals is mainly developed in the surface layers of the ice cover as well as the ice formed due to the infiltration of the sea water and its subsequent freezing in the lower layers of the snow cover. It is demonstrated that under the conditions of coastal Antarctic, the lamination of the structure during the period of ice cover formation and its subsequent development is the result of heavy precipitation in the form of snow and the formation of the large amount of snow sludge and crystals of intrawater ice (frazil ice) on the open water. The main distinctive feature of the Antarctic sea ice is its seasonal stratification with the formation of the surface layer of recrystallized ice and underlying destructive layers including the water interlayer in the ice column. The provision of the safety of overice movement of machinery requires the development of methods of continuous remote control of the snow-ice stratum of the fast ice. 相似文献
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The analysis of the long-term variability and spatiotemporal conjugacy of formation processes of ice conditions in the water areas of the Laptev, East Siberian, and Chukchi seas is carried out on the basis of the available data on the ice cover conditions in the above seas. On the whole, the type of relationships between the ice processes in the system of East Arctic seas indicates the existence of certain mechanisms generating the wave processes in the climatic system of the Arctic Basin manifested in the phase opposition in the development of ice conditions on the western and eastern peripheries of the basin under consideration. The statistical analysis of series of the ice coverage of water areas under consideration demonstrated that the existence of the long-term trend of this characteristic in some seas has its spatiotemporal features: the probability of the trend existence increases from west to east (from the Laptev Sea to the Chukchi Sea) and the trends are of opposite signs. 相似文献
4.
The results are presented of the statistical analysis of correspondence between the model simulations and observations of
temperature changes on the territory of Russia. Three model ensembles are considered, differing in the level of taking account
of the impact of external forcings on the climate system of the Earth. For each of them, the statistical correspondence is
estimated between the observed surface air temperature variations in the second half of the 20th century and at the beginning
of the 21st century and model simulations taking account of the natural variability typical of the climate system. The analysis
demonstrated that, in spite of the uncertainties associated with the differences in the representation of anthropogenic and
natural external forcings on the climate in model simulations as well as with the imperfection of climate models and with
internal variability of the climate system, the model experiments enable to obtain the relevant information both on the temporal
evolution of temperature changes on the territory of Russia and on their spatial peculiarities. 相似文献
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自20世纪90年代后期以来,热带气旋强度变化研究越来越受到人们的重视,随着研究的不断深入,热带气旋强度变化研究取得了可喜的进展,文中总结近年来热带气旋强度变化的主要研究成果,主要包括(1)热带气旋的发生、发展和最大可能强度的研究;(2)行星涡度梯度、环境均匀流、环境流场垂直切变以及热带气旋外流与环境流的相互作用对热带气旋强度的影响及物理机制;(3)热带气旋结构与强度的变化关系,着重总结环境流场导致的非对称结构变化而引起的热带气旋强度变化以及对涡旋倾斜发展理论验证,分析了涡旋Rossby波的最新研究;(4)海洋热状况变化以及海洋飞沫对热带气旋强度的影响研究成果。分析指出,今后进一步开展用现代化卫星探测资料研究热带气旋强度变化外,还应加强热带气旋外流与环境流场的相互作用,海-气交界面的参数化问题,热带气旋结构变化与TC强度变化关系以及这种关系的物理本质的研究,通过深入研究,认识热带气旋强度变化的物理机制,提高热带气旋强度变化的预报能力。 相似文献
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两个中尺度对流系统的降水结构和闪电特征 总被引：7，自引：3，他引：7
对两个处于不同发展阶段的中尺度对流系统(MCS)降水结构的分析结果表明,处于初生至发展阶段的MCS,对流降水和层云降水的面积比相对较大,处于成熟至消亡阶段的MCS的相对较小。本文进一步分析了这两个MCS个例在6km高度处的雷达回波特征及其和闪电的关系,结果表明处于初生至发展阶段的MCS的绝大部分事件(闪电资料的一种)集中发生在MCS中的强对流单体回波区,而对处于成熟至消亡阶段的MCS,事件集中发生在对流区和对流云向层云转化的回波区。 相似文献
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A numerical experiment was carried out on individual cases of severe convections in the Jianghuai area under cold vortex on April 28, 2015 in order to study the impact of wind field variations at the middle and low troposphere on the development and structure of storms. The results show that the structure and development of convective storm is highly sensitive to the changes of wind fields, and the adjustment of wind field at the middle or low troposphere will lead to significant changes in the development and intensity of storms. When the wind field at the middle or low troposphere is weakened, the convective development suffers different degrees of attenuation compared with the control experiment, and the ways of attenuation of the two levels are different. In the attenuation test of wind field at the middle level, convection is obviously weak at all stages of its development, while for the wind field at the low level, the convective development is weak only in the initial development stage of storm. On the contrary, the enhancement of the wind field at the middle or low troposphere is conducive to the development of convection, especially the enhancement of the wind field at the middle troposphere. In comparison, the convection develops rapidly in this test, as the most intensive one. The wind field variations have a significant impact on the structure and organization of the storm. The enhancement of the wind field at the middle troposphere makes for the intension of the middle-level swirl of convective storm, the reduction of the storm scale, and the organized evolution of convection. The development of the wind field at the low level troposphere is conducive to the development of the low-level secondary circulation of the storm and the cyclonic vorticity at the middle and low levels at the inflowing side. 相似文献
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A. F. Nerushev M. A. Novitskii O. Yu. Kalinicheva L. K. Kulizhnikova L. I. Milekhin D. E. Chechin 《Russian Meteorology and Hydrology》2013,38(2):61-70
The dynamics of atmospheric characteristics in the zone of the cyclone which provoked the dangerous atmospheric phenomenon, the heavy snowfall over the center of the European part of Russia in April 2012, is studied using the data of surface and satellite measurements. Besides the observational data from the meteorological stations, the results are used of the measurement of meteorological variables at the high-altitude meteorological mast in Obninsk and of surface concentration of minor gas components. Revealed is a number of interesting features associated with the passage of the cyclone cloud system over the observational point: the dramatic air temperature drop throughout the 300-m layer of the atmosphere, the formation of intensive vertical motions, and the significant temporal variability of O3 and NO2 concentration. The intensity and the total amount of precipitation falling during the cyclone passage are determined using the data of optical measurements of SEVIRI, AVHRR, and MODIS instruments of geostationary and polar orbiting satellites. Demonstrated is the satisfactory agreement of the computed precipitation characteristics with the results of observations at the network of meteorological stations. 相似文献
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基于三维近地面闪电先导发展随机模式,通过改变先导初始电位和建筑物几何特性,分析各种情况下的侧击雷电发生概率,探讨侧击雷电产生原因及影响因素。结果发现:建筑物尖端电场畸变值是影响侧击雷电产生的重要参量,当下行先导靠近建筑物且传播位置低于建筑物的高度时,建筑侧面电场畸变值达到触发阈值,侧击雷电易产生;下行先导的初始电位以及建筑物几何特性（高度和宽度）是影响侧击雷电发生概率的重要因素,当下行先导初始电位在-9~-3 MV范围内,侧击雷电发生概率呈先增加后降低的趋势,当初始电位为-4.5 MV时,侧击雷电的发生概率达到峰值;当建筑物高度在50~150 m范围内,侧击雷电发生概率随着高度增加呈先增加后减少的趋势;当建筑物高度为100 m时,侧击雷电发生概率达到峰值;当建筑物宽度在30~70 m范围内,侧击雷电发生概率随建筑物宽度呈递减趋势;当建筑物宽度为30 m时,侧击雷电的发生概率达到峰值。 相似文献
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Discussed are the results of long-term hydrophysical studies carried out on the northeastern shelf of Sakhalin Island in the area of summer-autumn fattening of the Okhotsk-Korea population of grey whales. It is demonstrated that the inflow of water desalinated by the Amur River runoff and the coastal upwelling caused by the summer monsoon are of great importance for the hydrological regime in the given area. These phenomena are interrelated and depend on interannual variations of atmoispheric circulation. Presented are the results of studying the parameters of internal waves obtained using the anchored autonomous vertical system of measurement. Measured are the velocities of the orbital movement of water particles in the propagating nonlinear internal waves and the respective vertical displacements of water layers. Demonstrated are the peculiarities of the thermohaline structure of water under the slick formed on the sea surface by the internal wave. 相似文献
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青藏高原地面感热对北半球大气环流和中国气候异常的影响 总被引：24，自引：7，他引：17
在青藏高原地面感热通量的基本气候特征以及异常变化的空间结构和时间演变趋势研究的基础上,进一步就高原地面感热异常对北半球大气环流和中国气候异常的影响进行诊断研究,并利用IAP2-LAGCM对青藏高原地面感热异常的影响进行了数值试验.结果表明:冬季地面感热在青藏高原西部、藏南谷地、横断山地区异常偏强,中、东部异常偏弱时,可使北半球500 hPa高度场表现出较明显的EU型和PNA型;高原西部、青海中北部异常偏弱,高原中部及东南部异常偏强时,使北半球100 hPa高度场的年际差异加强;西部、南部为正,柴达木及青海东部地区为负时,则新疆南部、西北东部及江南地区少雨,全国大部地区气温偏高.夏季高原地面感热通量距平特征为西南、藏南谷地、横断山区偏强,高原大部(中心在青海南部)异常偏弱时,则500"a高度场上青藏高原南部(孟加拉湾)高度偏高,高原北部高度偏低,负值区在帕米尔;当感热通量距平特征为高原西南、藏南谷地、横断山区偏弱,高原大部异常偏强时,有利于南亚高压的建立与维持;当地面感热通量呈南正北负距平差异时,长江上游、黄河源头及西北地区东部和东北部分地区降水量比常年偏多,气温偏低,中国东部、南部降水偏少,气温偏高.通过数值模式进行的敏感性试验证实了大气环流及区域气候变化对青藏高原地面感热总体异常的响应.
相似文献
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北京相当暴雨日数的气候特征 总被引：9，自引：0，他引：9
根据北京99年6～8月的逐日降水资料和274年6～8月总降水量资料， 分析了相当暴雨日数与总降水量及旱涝等级的相关性，给出相当暴雨日数与总降 水量的定量关系式，建立了北京274年汛期相当暴雨日数资料序列。分析表明: 相当暴雨日数概念的引入，可以把汛期总降水量中暴雨过程降水与非暴雨过程降 水分开，证实汛期旱涝变化只取决于暴雨过程的总次数和强度；相当暴雨日数是 一个气候统计量，有与总降水量一致的周期变化，但其年际变率和3.5年周期比 总降水量更显著，其概率分布满足泊松分布；与旱涝等级比较，相当暴雨日数与 总降水量的相关性更好，且有利于研究形成汛期旱涝灾害的暴雨过程特征。 相似文献
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Summary In this paper, an attempt is made to examine the influence of the physical forcings of an atmospheric general circulation model (AGCM) in the reduction of the systematic errors of the tropical forecasts. A number of major modifications in the parameterization of physical processes were carried out in the operational forecasting system of the European Centre for Medium Range Weather Forecasts (ECMWF) during the period 1984–88 largely in an attempt to reduce the conceptual weaknesses in their formulation. A large number of studies (Slingo et al., 1988; Tiedtke et al., 1988; etc) have demonstrated the positive impact on the reduction of tropical forecast errors to various changes in the treatment of physical processes in the ECMWF model.Keeping in view of these facts, the evaluation of the systematic errors of the ECMWF tropical forecasts is carried out for a period prior to the incorporation of major modifications in the parameterization of physical processes (1984) and corresponding period after such major changes are implemented in the operational AGCM of ECMWF (1988). The paper describes a detailed comparison of the tropical forecast errors for summer monsoon seasons (June-August [JJA]) of 1984 and 1988 in order to bring out the impact on tropical simulation of various improvements in the treatment of physical processes.The results demonstrate a dramatic reduction in the systematic errors of the tropical circulation together with an enhancement of the hydrological cycle to a realistic climatological level with the incorporation of major changes in the treatment of physical processes. Similar improvements are also observed in the winter simulation. In spite of major improvements in the simulation of tropical circulation, the nature of the tropical systematic errors of the ECMWF AGCM, however, remains unchanged. Thus, the inference of the study indicates the requirement of a new approach to the problem of parameterization of physical processes particularly, convection, radiation, boundary layer and their interactions for further reduction of the tropical forecast errors.With 14 Figures 相似文献
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海陆分布对海气相互作用的调控和副热带高压的形成 总被引：7，自引：3，他引：4
首先回顾了近年来关于副热带高压形成和变异研究的若干动力学进展,阐明夏季副热带“四叶型”LOS-ECOD加热分布型的内涵。在此基础上研究海陆分布对海气相互作用的调控,揭示了“四叶型”加热形成的物理基础,并进一步阐明“四叶型”加热拼图及其与副热带高压形成和变异的联系。 文章还回顾了关于副热带高压中短期变异的动力研究的最新进展。给出了影响中国江淮流域持续性降水的副热带高压三维结构的空间分布型;指出东西风带扰动的传播和高／低纬扰动的正压发展是影响副热带高压变异和中国夏季降水的一种可能机制,最后证明青藏高原夏季的强加热能激发纬向非对称不稳定发展,产生南亚高压的东／西部型双模态及准双周振荡。还证明初夏低纬的强对流降水／台风也能激发纬向非对称不稳定发展,影响西太平洋副热带高压异常和中国淮河流域的持续性降水。 相似文献
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利用数值模式再分析数据和常规观测资料,分析研究2009年6-8月西太平洋副热带高压(以下简称副高)连续5次北抬至偏北位置,且异常稳定维持,造成江淮流域干旱少雨(空梅)之缘由.通过合成、相关等分析方法探讨西风带、副热带、热带主要大气环流系统之间的相互影响和作用,并利用全型涡度方程探讨副高北抬和强度维持的主要机制.结果表明:(1)西风带波动的传播与副高变化关系密切,西太平洋副高的北抬过程起始于中段副高(140°～160°E)强度加强;(2)副高北抬之前孟加拉湾东部有明显的对流活动,对于副高的北抬和加强有一定的指示意义,而副高南侧的对流活动与副高北抬之间是一种伴随关系;(3)涡度场变化分析可知,副高北抬的关键因素是中高纬度槽脊变化引起的东亚沿海负涡度的增加. 相似文献
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A synoptic mechanism of the formation of atmospheric circulation anomalies over the tropics of the Indian and Pacific oceans observed during the La Niña 2010–2011 culmination is considered using the daily data of the NCEP/NCAR reanalysis. It was established that the most destructive flood during the whole modern history of Australia was caused by the unprecedented activity of the tropical cyclogenesis in the circulation system of the Australian summer monsoon. The tropical cyclones affected in turn the monsoon regions of Australia both from the Indian Ocean through the system of the equatorial zone of westerlies and from the Pacific Ocean through the system of the eastern trade wind. The Pacific trade wind during the Australian flood was maximally developed and the South Pacific high was shifted considerably from the coast of Peru and Chile to the center of the ocean. It is demonstrated that the maximum values of negative SST anomalies were observed not in the east of the Pacific Ocean as in the case of the “canonical” La Niña but they were shifted significantly to the west to the line of the date change. All this enables to refer the extreme La Niña 2010–2011 to La Niña of Modoki type. 相似文献
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利用联合台风预警中心(Joint Typhoon Warning Center,JTWC)最佳路径资料、逐小时降水资料和ERA5再分析资料,研究2017年5月26—31日孟加拉湾风暴与高原低涡共同影响下青藏高原一次强降水过程,结果表明:风暴和南支槽共同作用下建立的孟加拉湾至青藏高原的水汽输送带为高原低涡-切变线区域的降水提供水汽。南支槽后冷气流在青藏高原南部陡坡下沉形成冷垫,孟加拉湾偏南暖湿气流首先沿冷垫向北抬升,爬上青藏高原后向北在高原切变线附近再次抬升,增加降水区地表至对流层高层大气中的可降水量。风暴偏南风暖湿气流与青藏高原北部干冷空气交汇产生锋生,大气湿斜压性显著增长,湿等熵线密集陡立导致垂直涡度剧烈发展,有利于高原低涡加强。风暴北上过程中其高层反气旋式出流加强青藏高原槽前西南风高空急流,辐散增强有利于低层切变线发展和高原低涡东移,产生大范围强降水。高原低涡切变线与风暴水汽输送的正反馈作用,为降水区提供持续视热源和视水汽汇,有利于青藏高原降水系统的维持和发展。 相似文献
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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. 相似文献