共查询到20条相似文献，搜索用时 31 毫秒
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Yu. I. Portnyagin E. G. Merzlyakov T. V. Solovs’eva N. A. Makarov 《Izvestiya Atmospheric and Oceanic Physics》2006,42(1):93-104
The wind circulations in the mesosphere-lower thermosphere at polar latitudes of the Northern and Southern hemispheres are compared on the basis of long-term monthly-mean data on the prevailing zonal and meridional winds and on the parameters of diurnal and semidiurnal migrating tides obtained from the international network of radar stations. Comparison of the seasonal cycles and vertical profiles of the prevailing winds and tide parameters points to the existence of significant distinctions between the hemispheres. These distinctions are most clearly pronounced, first, in the prevailing meridional winds (for example, the annual mean winds in the polar regions have opposite directions in different hemispheres) and, second, the annual cycles of semidiurnal-tide amplitudes, as well as the character of changes in the tide phase with height, are fundamentally different for the Northern and Southern hemispheres. Along with these, significant distinctions are revealed in the prevailing zonal winds and in the diurnal-tide parameters. 相似文献
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N. M. Gavrilov A. V. Koval’ A. I. Pogorel’tsev E. N. Savenkova 《Izvestiya Atmospheric and Oceanic Physics》2013,49(4):367-374
We have developed a parameterization of the dynamical and thermal effects of stationary orographic waves (SOWs) generated by the earth’s surface topography and included it into the general circulation model of the middle and upper atmosphere. We have analyzed the sensitivity of atmospheric general circulation at tropospheric to thermospheric altitudes to the impact of SOWs propagating from the troposphere. Changes in atmospheric circulation due to variations in the SOW generation and propagation have been considered for different seasons. It has been shown that, during solstices, the main dynamical and thermal impacts the middle atmosphere of winter hemispheres, where the SOW-induced changes in the velocity of zonal circulation can reach 30%. During equinoxes, the SOW impact is distributed more homogeneously between the Northern and Southern hemispheres, and the relative changes in the velocity of zonal circulation of the middle atmosphere may constitute 10%. 相似文献
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A. N. Fakhrutdinova V. V. Gur’yanov A. Yu. El’kin 《Izvestiya Atmospheric and Oceanic Physics》2006,42(1):60-67
The distributions of kinetic energy (KE) and available potential energy (APE) in the lower and middle atmosphere of the Northern and Southern hemispheres over the period 1992–2003 are investigated. Annual mean values of the amplitude and phase of annual and semiannual oscillations in the zonal and eddy forms of KE and APE are calculated in the height range 0–55 km (1000–0.316 hPa) for the 21st layer. A clearly pronounced annual cycle of the zonal and eddy components of KE and APE with maxima in the winter season are observed in the troposphere of both hemispheres. In the lower stratosphere, the annual-cycle maximum is shifted toward the summer season because of the meridional gradient of the zonal mean temperature. In the stratosphere of both hemispheres, along with annual oscillations, semiannual oscillations are present in all forms of energy. The intensity of these oscillations for the zonal KE and APE at the upper-stratosphere heights is comparable to the intensity of annual oscillations. A local structure of the energy regime of the upper mesosphere-lower thermosphere is investigated against the background of the global energy regime from the data of meteor sounding in Kazan. It is shown that, for both the global and regional regimes, specific features of the phase profiles of energy characteristics can be explained by the presence of barriers during the propagation of wave disturbances along the vertical. 相似文献
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In this paper the impacts of the anomalous SST in the warm pool area of the Western Equatorial Pacific on the winter time circulation and the East Asian monsoon are studied by using the NCAR CCM. It is found that the abnormal heating in the warm pool area will change the strength and the position of the Walker Cell in the Equatorial Pacific and the anti-Walker Cell in the equatorial Indian Ocean. Both the Walker and anti-Walker Cells are strengthened. The local Hadley Cells over two hemispheres near the warm pool are also strengthened. The subtropical highs in two hemispheres become stronger and move poleward slightly. The westerly jets in the extratropical regions have similar changes as the subtropical highs. The winter monsoon in South-East Asia is weakened by the abnormal heating in the warm pool. The experiment also show that there are wave trains emanating from surrounding areas of the warm pool to the high latitudes, causing various changes in circulations and local weather. 相似文献
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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
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Outputs from simulations performed with current atmosphere-ocean general circulation models for the Fourth Assessment Report of Intergovernmental Panel on Climate Change (IPCC AR4) are used to investigate the evolution of sea ice over the 20th and 21st centuries. We first use the results from the “Climate of the 20th Century Experiment” to assess the ability of these models to reproduce the observed sea ice cover changes over the periods 1981–2000 and 1951–2000. The projected sea ice changes over the 21st century in response to the IPCC Special Report on Emission Scenarios A1B are then examined. Overall, there is a large uncertainty in simulating the present-day sea ice coverage and thickness and in predicting sea ice changes in both hemispheres. Over the period 1981–2000, we find that the multimodel average sea ice extent agrees reasonably well with observations in both hemipsheres despite the wide differences between the models. The largest uncertainties appear in the Southern Hemisphere. The climate change projections over the 21st century reveal that the annual mean sea ice extent decreases at similar rates in both hemispheres, and that the reduction in annual mean sea ice volume is about twice that of sea ice extent reduction in the Northern Hemisphere, in agreement with earlier studies. We show that the amplitude of the seasonal cycle of sea ice extent increases in both hemispheres in a warming climate, with a larger magnitude in the Northern Hemisphere. Furthermore, it appears that the seasonal cycle of ice extent is more affected than the one of ice volume. By the end of the 21st century, half of the model population displays an ice-free Arctic Ocean in late summer. 相似文献
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V. I. Byshev V. G. Neiman Yu. A. Romanov I. V. Serykh D. M. Sonechkin 《Oceanology》2016,56(2):165-171
The statistical significance of Global Atmospheric Oscillation (GAO), whose main element is the well-known El Niño–Southern Oscillation in the equatorial Pacific, was assessed from monthly mean atmospheric pressure data at sea level at the nodes of a regular 5° × 5° grid covering the entire surface of the Earth. The data were collected in 1920–2012. It was found that statistically reliable GAO signals cover almost the entire tropical zone and they also appear at mid- and high latitudes of both hemispheres. 相似文献
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B. V. Kiselev 《Izvestiya Atmospheric and Oceanic Physics》2016,52(1):33-36
Surface temperature anomalies are studied using the methods of recurrence plots and statistical R/S analysis, as well as the Higuchi method for determining fractal dimension. Anomalies of the surface temperature above continents and the temperature in the World Ocean regions and in the Northern and Southern hemispheres are considered independently. It has been indicated that anomalies are more stochastic and deterministic for land and ocean surfaces, respectively. 相似文献
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Comparative Late Pleistocene Paleoceanographic Changes in the Mid Latitude Boreal and Austral Western Pacific 总被引：2，自引：0，他引：2
Middle latitudes of the northern and southern hemispheres of the western Pacific are the sensitive areas for the climatic change. We reconstruct the variation in primary productivity to evaluate the shift of the transition zone between the central water mass and cold water in the both hemispheres. In cores S2612 and LH3166, which are located around boreal and austral 35 degree, the mean COrganic/N atomic ratios are 7.8 and 7.2, respectively. Therefore it is suggested that organic matter is mainly of marine origin (excluding the middle Stage 6 to Stage 7 with the high COrganic/N atomic ratios in core LH3166). Primary productivities estimated from these cores in the middle latitudes of the western Pacific during the late Pleistocene demonstrate similar profiles. Maxima are observed at late Stage 2, late Stage 4 (middle Stage 4 for L3187) and late Stage 6 while minimum values were observed at Stage 5. Mass accumulation rates of organic carbon and biogenic opal also show similar profiles in these cores. These results and paleontological evidence show that the transition zone between Subtropical and subarctic waters almost synchronously migrated along the latitudinal transection during the last 150 kyr. 相似文献
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利用小波分析方法,对2003-2008年周平均的Argo(地转海洋学实时观测阵)海温资料进行了分析,给出了全球上层海温年周期和半年周期振荡的空间分布特征.结果表明,南北半球中高纬地区以表层海温的年周期变化为主,在低纬度地区,表层海温以半年周期为主,而温跃层附近海温既有年周期也有半年周期(赤道太平洋、东南印度洋和赤道西大西洋以年周期为主;赤道东、西印度洋以半年周期为主).南北半球中高纬的年周期海温和北半球中纬度的半年周期海温在表层范围最大,显著性最高,强度最强,位相最前.随深度的增加,范围减小,显著性降低,强度减弱,位相滞后.信号主要集中在水深50 m以上,影响深度在150m以浅;赤道附近的太平洋和热带东南印度洋的年周期海温以及赤道东、西印度洋的半年周期海温在水深100m范围最大,显著性最高,强度最强,位相最前,信号主要集中在温跃层附近,影响深度均可达500m. 相似文献
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A. M. Batchaev 《Izvestiya Atmospheric and Oceanic Physics》2011,47(4):508-516
Plane incompressible flow under an external spatially doubly periodic force is numerically simulated. It is shown that the stationary point of the system loses stability when the Reynolds number crosses the first critical value and a periodic solution appears from the resonant interaction of modes. Self-oscillation parameters in the structural element of the flow are calculated and compared with the results obtained in a laboratory cell. It is assumed that the phenomenon of a quasi-two-year cycle of the atmospheric circulation is connected with the parametric resonance resulting from seasonal variations of the absolute vortex on hemispheres like in a unified hydrodynamic system. 相似文献
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A. N. Gruzdev 《Izvestiya Atmospheric and Oceanic Physics》2017,53(4):441-448
Using the data of the ERA-Interim reanalysis, we have obtained estimates of changes in temperature, the geopotential and its large-scale zonal harmonics, wind velocity, and potential vorticity in the troposphere and stratosphere of the Northern and Southern hemispheres during the 11-year solar cycle. The estimates have been obtained using the method of multiple linear regression. Specific features of response of the indicated atmospheric parameters to the solar cycle have been revealed in particular regions of the atmosphere for a whole year and depending on the season. The results of the analysis indicate the existence of a reliable statistical relationship of large-scale dynamic and thermodynamic processes in the troposphere and stratosphere with the 11-year solar cycle. 相似文献
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Tariq Masood Ali Khan Dewan Abdul Quadir T. S. Murty Anwarul Kabir Fahmida Aktar Majajul Alam Sarker 《Marine Geodesy》2002,25(1):133-143
Oceanic Islands in the Pacific and Indian Oceans have extremely small land areas, usually less than 500 km2, with maximum height about 4 m above sea level. The Republic of Maldives is an independent island nation in the Indian Ocean south of Sri Lanka which stretches vertically in the Indian Ocean from 07° 06'N - 0° 42'S. The land area of this island country is about 300 km2, and none of Maldives' 1190 islands has an elevation more than 3 m above sea level. In fact the Maldives has the distinction of being the flattest country on earth, making it extremely vulnerable to the effects of global warming. Of the south Asian countries, the Maldives is the most vulnerable nation, facing severe consequences as a result of global warming and sea level rise (SLR). Because of their obvious vulnerability to SLR, the Government of Maldives is very much concerned about climate change. As global warming and the related SLR is an important integrated environmental issue, the need of the hour is to monitor and assess these changes. The present article deals mainly with the analysis of the tidal and Sea Surface Temperature (SST) data observed at Male and Gan stations along the Maldives coast in the northern and southern hemispheres, respectively. The objective of the analysis is to study the trends of these parameters. Trend analysis is also performed on the corresponding air temperature data of both stations. The results show that Maldives coastal sea level is rising in the same way (rising trend) as the global sea level. The mean tidal level at Male has shown an increasing trend of about 4.1 mm/year.Similarly at Gan, near the equator,it has registered a positive trend of about 3.9 mm/year.Sea level variations are the manifestations of various changes that are taking place in the Ocean-Atmosphere system. Therefore, the variations in SST and air temperature are intimately linked to sea level rise. It is found that SST and air temperature have also registered an increasing trend at both stations. The evidence of rising trends suggest that careful future monitoring of these parameters is very much required. Tropical cyclones normally do not affect the Maldives coast. However, due to its isolated location, the long fetches in association with swells generated by storms, that originated in the far south have resulted in flooding. Thus the rising rate of sea level with high waves and flat topography have increased the risk of flooding and increased the rate of erosion and alteration of beaches. 相似文献
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Relative Sea Level Changes in Maldives and Vulnerability of Land Due to Abnormal Coastal Inundation 总被引：1，自引：0，他引：1
Tariq Masood Ali Khan Dewan Abdul Quadir T. S. Murty Anwarul Kabir Fahmida Aktar Majajul Alam Sarker 《Marine Geodesy》2013,36(1-2):133-143
Oceanic Islands in the Pacific and Indian Oceans have extremely small land areas, usually less than 500 km2, with maximum height about 4 m above sea level. The Republic of Maldives is an independent island nation in the Indian Ocean south of Sri Lanka which stretches vertically in the Indian Ocean from 07° 06'N - 0° 42'S. The land area of this island country is about 300 km2, and none of Maldives' 1190 islands has an elevation more than 3 m above sea level. In fact the Maldives has the distinction of being the flattest country on earth, making it extremely vulnerable to the effects of global warming. Of the south Asian countries, the Maldives is the most vulnerable nation, facing severe consequences as a result of global warming and sea level rise (SLR). Because of their obvious vulnerability to SLR, the Government of Maldives is very much concerned about climate change. As global warming and the related SLR is an important integrated environmental issue, the need of the hour is to monitor and assess these changes. The present article deals mainly with the analysis of the tidal and Sea Surface Temperature (SST) data observed at Male and Gan stations along the Maldives coast in the northern and southern hemispheres, respectively. The objective of the analysis is to study the trends of these parameters. Trend analysis is also performed on the corresponding air temperature data of both stations. The results show that Maldives coastal sea level is rising in the same way (rising trend) as the global sea level. The mean tidal level at Male has shown an increasing trend of about 4.1 mm/year.Similarly at Gan, near the equator,it has registered a positive trend of about 3.9 mm/year.Sea level variations are the manifestations of various changes that are taking place in the Ocean-Atmosphere system. Therefore, the variations in SST and air temperature are intimately linked to sea level rise. It is found that SST and air temperature have also registered an increasing trend at both stations. The evidence of rising trends suggest that careful future monitoring of these parameters is very much required. Tropical cyclones normally do not affect the Maldives coast. However, due to its isolated location, the long fetches in association with swells generated by storms, that originated in the far south have resulted in flooding. Thus the rising rate of sea level with high waves and flat topography have increased the risk of flooding and increased the rate of erosion and alteration of beaches. 相似文献
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A. S. Kazmin 《Oceanology》2016,56(2):182-187
Global satellite sea surface temperature (SST) measurements and NCEP/NCAR reanalysis wind data for the period of 1982–2009 have been used to study the relationship between long-term variability of oceanic frontal zones (OFZ) and large-scale atmospheric forcing. Statistically significant positive correlations between the maximum magnitude of the meridional gradient of zonally averaged SST and meridional shear of zonal wind (which is an estimate of the Ekman convergence intensity) were found for all subpolar and subtropical OFZ of the World Ocean. Variability of the latitudinal position of OFZ cores may be associated with Ekman advection variability due to zonal wind variations. Strengthening of zonal wind results in a shift of subpolar OFZ cores to the south/north in the Northern/Southern hemispheres. 相似文献
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Measurements of the concentration of thallium in seawater collected from numerous ocean locations ranged from 12 to 16 ng kg−1. Variations between the Atlantic and Pacific Oceans, between the northern and southern hemispheres of the Pacific Ocean, and between surface and deep waters of both the Pacific and Atlantic oceans were comparable with the precision of the analyses. This relatively constant distribution indicates that the element's cycle in seawater may be similar to those of the alkali metals which are its principal biogeochemical analogues. 相似文献