共查询到20条相似文献，搜索用时 31 毫秒
1.
Izvestiya, Atmospheric and Oceanic Physics - International investigations into the correlation between tropical cyclones (TCs) and the ionosphere are associated with great difficulties in proving... 相似文献
2.
Ashish Routray Vivek Singh Ankur Gupta Devajyoti Dutta John P. George 《Marine Geodesy》2019,42(2):201-226
The present study evaluates the impact of vortex initialization (VI) scheme within the NCMRWF Global Unified model (NCUM-G) for prediction of tropical cyclones (TCs) formed over Bay of Bengal (BoB). For this purpose, two numerical experiments such as control simulation (CNTL) without using VI scheme and VOTX simulation using the VI scheme in the NCUM-G are performed by considering four landfalling TCs formed over BoB basin during the year 2016–17. The results suggest that even though TCs are large synoptic systems, the introduction of VI scheme has a positive impact on the prediction of the location, movement, intensity and development of rain bands associated with the TCs. The initial vortex position and landfall position errors are reduced by ～64% and ～39% in VOTX simulations over CNTL, respectively. The mean track errors of all the four TCs are reasonably improved by ～58% in VOTX over CNTL. The equitable threat score (ETS) and frequency bias are significantly improved in the VOTX for all the TC cases as compared to CNTL. Study results provide a positive proof of concept that the VI scheme within the NCUM-G can help to improve the simulation of track and intensity of TCs over BoB. 相似文献
3.
Zekai Ni Jiancheng Yu Xuekun Shang Wenming Jin Yeteng Luo Philip A Vetter Huichang Jiang Liu Yu Sumin Liu Hongzhou Xu 《海洋学报(英文版)》2021,40(1):103-112
The evolution of thermohaline structure at the upper ocean during three tropical cyclones(TCs) in the Northwest Pacific was studied in this study based on successive observation by two new-style underwater gliders during fall 2018. These remote-controllable gliders with CTD sensor enabled us to explore high frequency responses of temperature, salinity, mixed and barrier layers in the upper ocean to severe TCs in this area. Results showed that three significant cooling-to-warming and stratification destructing-to-reconstructing processes at the mixed layer occurred during the lives of three TCs. The maximal cooling of SST all reached ≥0.5℃ although TCs with different intensities had different minimal distances to the observed area. Under potential impacts of solar radiation, tide and inertial motions, the mixed layer depth possessed significant high-frequency fluctuations during TC periods.In addition, barrier layers appeared and vanished quickly during TCs, accompanied with varied temperature inversion processes. 相似文献
4.
At present the mutual influence of tropical cyclones (TCs) has been investigated to a much lesser extent than the cyclones themselves. Most frequently, such investigations are restricted to the study of the influence of the interaction of two TCs on their motion. However, actually, the mutual influence of TCs is much more diverse. For example, each cyclone alters the state of the medium (in particular, decreases the heat store of the upper ocean layer), i.e., affects the subsequent cyclones. Under conditions of a limited energy resource of the medium, cyclones, existing simultaneously, “compete,” to a degree, with each other. These and other similar circumstances have made it practical to consider tropical cyclones and the environment as interdependent elements of a complex open system. This study considers two versions of nonlinear models describing the interaction of TCs with the upper ocean layer and with one another similarly to a number of well-known and verified models of synergetics (interaction of populations, dynamics of optical quantum generators). It is shown that the models reproduce some very important qualitative features of the evolution of TC intensity. 相似文献
5.
The problems of recording the ionospheric response to tropical cyclones (TCs) and the possibilities for detecting such a response
using GPS (Global Positioning System) signals are discussed. Investigations of ionospheric effects of tropical cyclones with
the use of different geophysical methods and technologies of GPS application for remote diagnostics of the ionosphere are
reviewed. The results of investigating the action of tropical cyclones on the Earth’s ionosphere on the basis of measurements
of variations in the total electron content at the global network of ground-based double-frequency GPS receivers are presented.
It is shown that (a) the recording of tropospheric effects in the ionosphere is associated with the difficulties of detecting
weak disturbances and their identification against the general background of variations and with the problems of identification
of sources of such disturbances; (b) geomagnetic storms mask the effects of tropospheric disturbances in the upper ionosphere;
and (c) when identifying the ionospheric effects of tropical cyclones, one must pay the bulk of attention to the search for
the enhancement of the intensity of disturbances in ionospheric parameter variations. 相似文献
6.
1949—2009年登陆和影响浙江的热带气旋分析 总被引：1，自引：0，他引：1
通过对1949—2009年61年间登陆和影响浙江的热带气旋的时空分布特征、主要影响路径等的分析,发现在7—9月份登陆浙江的热带气旋占登陆总数的92.5%,7—9月份影响浙江的热带气旋占影响总数的82%。影响浙江的热带气旋中登陆福建或在台湾海峡消失的热带气旋占的比重最多。虽然西北太平洋上热带气旋生成个数近年来大幅减少,但登陆浙江的强台风有明显增多的趋势。随着气候的变暖,海水温度的增高,热带气旋生成的时间提早,结束的时间偏迟。另外通过对热带气旋影响时各海岛、沿海和内陆站的大风、暴雨的分析,发现热带气旋影响期间容易引起大风天气的是大陈和嵊山站;容易引起暴雨天气的是温岭、临海和温州站。本文还分析了验潮站最大增水超过1m、2m、3m的时空分布特征。 相似文献
7.
A. Baz 《Ocean Engineering》1986,13(4)
Excessive temperature rise during compression inside hyperbaric chambers is a serious source of discomfort for their occupants. In this article a new class of vortex tube-assisted hyperbaric chambers is presented where such temperatures are reduced passively without the need for external power source. The vortex tube is utilized as means for generating the necessary cooling effect as the gases flow from their storage tanks into the chamber.Mathematical and experimental models of the new concept have been developed to study the dynamic and thermal characteristics of the vortex tube-assisted chambers under different conditions. Comparisons between such characteristics and those of unassisted chambers suggest the potential of the vortex tube assist in reducing the temperatures inside the hyperbaric chambers and accordingly the size of the installed cooling systems required for maintaining certain comfortable temperature levels. 相似文献
8.
An instrumented balloon launched from Kiruna during the SESAME experiment displayed simultaneous local decreases of water vapor and aerosol at 2 different potential temperature levels 410 K and 364 K. Despite the similar characteristics present at both levels, 2 different explanations are given for these laminae. At the highest level, the air mass showing the water vapor and aerosol decrease is found when the balloon travels in the vortex edge region. A back trajectory shows that this air mass was trapped in the vortex edge region for several days and processed by a PSC causing the water vapor and aerosol decreases. On the other hand, the lowest level air mass was found to be in the sub‐vortex region. No local conditions can explain the observed decreases of water vapor and aerosol. Back trajectories show that this air mass originates from middle latitudes. Although the back trajectories calculated in these conditions are more subject to caution, comparison of several characteristics at the measurement point and at the middle latitude sites corroborates the explanation of the decrease of water vapor and aerosol by the origin of the air mass. 相似文献
9.
Physical causes controlling the influence of the main cosmic factors on the state of the ionosphere and, further, on weather
and climatic phenomena, including the global warming, are investigated. These investigations are based on the Rydberg excitation
of the experimentally observed microwave radiation of the Earth’s ionosphere by energetic ionospheric electrons. This microwave
radiation virtually freely penetrates into the lower atmosphere, providing channels for the influence of solar variability
on terrestrial phenomena. The factors causing an anomalous wear of Russian pipeline systems are also analyzed, and the methods
for reducing their rapid corrosion through taking into account the influence of heliogeomagnetic and ionospheric disturbances
are described. Such investigations are supported by the space experiment on permanent monitoring of the factors controlling
heliogeomagnetic activity, i.e., fluxes of ionizing radiation of the Sun and fluxes of electrons precipitating from the radiation
belts. 相似文献
10.
Ponomarev V. M. Khapaev A. A. Yakushkin I. G. 《Izvestiya Atmospheric and Oceanic Physics》2008,44(1):45-52
An approximate theory is constructed to describe quasi-two-dimensional viscous incompressible flows. This theory takes into account a weak circulation in the vertical plane and the related divergence of the two-dimensional velocity field. The role of the nonlinear terms that are due to the interaction between the vortex and potential components of velocity and the possibility of taking into account the corresponding effects in the context of the concept of bottom friction are analyzed. It is shown that the nonlinear character of friction is a consequence of the three-dimensional character of flow, which results in the effective interaction of vortices with vertical and horizontal axes. An approximation of the effect of this interaction in quasi-two-dimensional equations is obtained with the use of the coefficient of nonlinear friction. The results based on this approximation are compared to the data of laboratory experiments on the excitation of a spatially periodic fluid flow. 相似文献
11.
We analyze the effect of geomagnetic activity on variations in quasi-static electric field strength and the horizontal geomagnetic
field component in the band of periods of tidal and planetary waves. Variations in oscillation intensities and periods in
the power spectra of these parameters synchronously with the K
p
index are shown. Taking into account the relationship of these parameters with the air pressure, we suggest a possible biophysical
mechanism of the relation between the state of the human cardiovascular system and geomagnetic activity by means of resonant
interaction with the environment. In periods of high geomagnetic activity, the air pressure and temperature vary due to an
increase in atmospheric transparency as a result of the Forbush decrease in the cosmic ray flux rate. It is these variations
that directly affect humans. 相似文献
12.
The solar radiation coming to the Earth’s ellipsoid is considered without taking into account the atmosphere on the basis of the astronomical ephemerides for the time interval from 3000 BC to 3000 AD. Using the regression equations between the Earth’s insolation and near-surface air temperature, the insolation annual and semiannual climatic norms of near-surface air temperature for the Earth as a whole and the hemispheres are calculated in intervals of 30 years for the period from 2930 BC to 2930 AD with 100 and 900- to 1000-year time steps. The analysis shows that the annual insolation rates of the near-surface air temperature of the Earth and the hemispheres decrease at all intervals. The semiannual insolation rates of the near-surface air temperature increase in winter and decrease in summer. This means that the seasonal difference decreases. The annual and semiannual rates of insolation near-surface air temperature of the Earth increase in the equatorial and decrease in the polar regions; the latitudinal contrast increases. The interlatitudinal gradient is higher in the Southern Hemisphere. It practically does not change in winter and increases in summer, most strongly in the Southern Hemisphere. 相似文献
13.
Ya. A. Virolainen Yu. M. Timofeyev A. V. Polyakov D. V. Ionov O. Kirner A. V. Poberovskii H. Kh. Imhasin 《Izvestiya Atmospheric and Oceanic Physics》2016,52(1):57-65
Chemistry climate models of the gas composition of the atmosphere make it possible to simulate both space and time variations in atmospheric trace-gas components (TGCs) and predict their changes. Both verification and improvement of such models on the basis of a comparison with experimental data are of great importance. Data obtained from the 2009–2012 ground-based spectrometric measurements of the total contents (TCs) of a number of TGCs (ozone, HNO3, HCl, and NO2) in the atmosphere over the St. Petersburg region (Petergof station, St. Petersburg State University) have been compared to analogous EMAC model data. Both daily and monthly means of their TCs for this period have been analyzed in detail. The seasonal dependences of the TCs of the gases under study are shown to be adequately reproduced by the EMAC model. At the same time, a number of disagreements (including systematic ones) have been revealed between model and measurement data. Thus, for example, the EMAC model underestimates the TCs of NO2, HCl, and HNO3, when compared to measurement data, on average, by 14, 22, and 35%, respectively. However, the TC of ozone is overestimated by the EMAC model (on average, by 12%) when compared to measurement data. In order to reveal the reasons for such disagreements between simulated and measured data on the TCs of TGCs, it is necessary to continue studies on comparisons of the contents of TGCs in different atmospheric layers. 相似文献
14.
We discuss specific features of the space distribution and the processes of assimilation and oxidation of the dissolved and emulsified fractions of oil hydrocarbons in Black-Sea waters and study the methods of parametrization of these processes proposed in the literature. We develop a procedure of parametrization of the processes of degradation of oil hydrocarbons taking into account their complex chemical compositions, characteristics of chemical and microbiological processes, and temperature dependences of these processes and perform numerical experiments aimed at the reconstruction of the seasonal variations of the large-scale space structure of the distribution of oil hydrocarbons in the aerobic zone of the Black Sea. 相似文献
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本文使用中国气象局、美国联合台风预警中心和日本气象厅的3套热带气旋最佳路径资料(CMA资料、JTWC资料和RSMC资料)分析了1951—2016年西北太平洋热带气旋活动特征。3套资料反映的结果如下:热带气旋主要发生在10°N—25°N范围内,且1980年前其位置点在纬度上有南移的变化趋势,1980年后则相反;移速主要分布在2~6 m/s区间,在25°N左右移速明显加快,1980年前移速呈显著减小趋势;最大持续风速主要分布在10~15 m/s区间,1980年前最大持续风速有减小趋势;在风速较大的区域热带气旋最大风速半径较小,2001—2016年热带气旋和台风最大风速半径每年分别减小0.46 km和0.54 km。CMA和RSMC资料的结果高度一致,而JTWC资料结果与它们都存在一定的差异。热带气旋位置点频数和强度的变化受资料间差异的影响较大,而其位置及移速的变化则受影响较小。 相似文献
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18.
各向同性均匀湍流近壁结构及泥沙起动 总被引：3，自引：1，他引：3
采用振动格栅产生的各向同性均匀湍流研究了泥沙的起动。应用PTV技术和局部光学放大技术对湍流场进行了测量，发现近壁面湍流动能的指数分布规律。分析了泥沙在均匀同性湍流中的起动机制，并用概率统计理论对泥沙的起动进行了定量的描述。通过测定泥沙起动事件的概率，得到了同种泥沙在不同流动参数下起动的临界湍流动能。 相似文献
19.
利用海底有缆在线观测系统获得的连续实时观测数据,研究了2016年6月2日至10月22日期间威海市西港海洋牧场底层海水溶解氧浓度的时间变化特征,并探讨了其影响机制。结果表明,观测期间底层海水溶解氧浓度整体呈先减小后增大的变化趋势,其变化范围为2.99 mg/L至11.43 mg/L,均值约为6.65 mg/L。进一步分析表明：（1）底层海水饱和溶解氧浓度的变化并不显著,于6月出现过饱和现象;（2）海水温度是底层海水溶解氧浓度日际变化和月变化的主要影响因素;（3）7月至8月中旬,在季节性温跃层抑制垂向混合和水温升高的共同影响下,底层溶解氧浓度总体呈下降趋势;（4）日平均风速与日平均海水溶解氧浓度的相关性并不显著,但大风期间底层海水溶解氧浓度存在先升高后降低的变化特征;（5）底层海水溶解氧浓度的日变化以全日周期为主,可能主要受生物过程、垂向混合扩散和潮流输运等日变化的影响。本研究对于进一步探讨山东半岛海洋牧场区域海水溶解氧的时空分布特征及其影响机制具有重要意义。 相似文献
20.
D. M. Ermakov A. P. Chernushich E. A. Sharkov I. V. Pokrovskaya 《Izvestiya Atmospheric and Oceanic Physics》2013,49(9):963-973
The possibility of utilizing a specialized approach to the space-time interpolation of satellite data that takes the kinematics of multiscale processes into account in solving the problems of remote sensing of fast processes in the Earth’s atmosphere is considered. The approach is borrowed from the rapidly progressing disciplines of machine vision and video data compression. The main advantages of this method are its completeness with respect to the input (interpolated) satellite data, its capacity to estimate the kinematics of multiscale processes and take it into account, a relatively low computational cost, and the ease of its software-algorithmic implementation. The problem of an “instantaneous” source of hidden energy for the intensification of Tropical Cyclone (TC) Katrina is solved based on the developed software-algorithmic approach using data from the SSM/I satellite radiometers of the DMSP mission. 相似文献