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31.
The formation of the fields of surface winds over the Black Sea occurs under the action of numerous physical factors. One
of the most important factors is the monsoon mechanism connected with the seasonal variations of buoyancy contrasts over the
sea and surrounding land. To separate the effects caused by this mechanism, we performed and described the numerical experiments
aimed at the evaluation of the sensitivity of the regional model of atmospheric circulation to the variations of land–sea
temperature contrasts. It is shown that the influence of these effects is restricted to the lower part of the atmosphere.
The presented estimates of the climatic fields of disturbances enable us to describe the monsoon mechanism specifying the
seasonal variability of the field of vorticity of the wind velocities and, as a consequence, the seasonal variability of the
large-scale circulation of waters in the Black Sea. 相似文献
32.
Land, marine, and satellite observations have been used to study changes in methane concentrations in the lower atmosphere during the warm months of the year (July through October) in Arctic regions having different potentials for methane production. The Atmospheric Infrared Sounder (AIRS) data for 2002–2013 are used to explore the interplay between local methane sources in the terrestrial region of the Eurasian Arctic and on the Arctic shelf over the warm period of the year. Linear trends in atmospheric methane concentrations over different Arctic regions are calculated, and a hypothesis of the relation of concentration variations to climatic parameters is tested. The combination of land, marine, and satellite observation is used to develop a conceptual model of the atmospheric methane field in the terrestrial part of the Russian Arctic and on the Arctic shelf. It is shown that the modern methane growth rate in the Arctic does not exceed the Northern Hemisphere mean. It is concluded that the methane emission in the Arctic has little effect on global climate compared to other factors. 相似文献
33.
O. A. Anisimov Ye. L. Zhiltcova V. Yu. Razzhivin 《Izvestiya Atmospheric and Oceanic Physics》2015,51(9):1051-1059
The NOAA satellite data for 1982–2012 are used to analyze current changes in plant productivity of the Russian boreal and tundra zones. Trends in the Normalized Difference Vegetation Index (NDVI) are calculated separately for the vegetation zones in the European, West Siberian, East Siberian, and Far East sectors of the Russian Arctic and are compared with each other. This index is the normalized difference in reflectance between the red and infrared regions of the spectrum and is widely used as an indicator of the photosynthetically active biomass amount. Multifactorial statistical analysis is used to analyze the link between the plant productivity characterized by NDVI and predictive climatic indices characterizing the temperature regime and precipitation. A statistical model is developed on the basis of the resulting set of regression equations and is used with a climatic projection to predict plant productivity changes across the zonal gradient from northern tundra to boreal forests. According to our results, the current increase in plant productivity, which is observed in all vegetation zones in the Arctic, will continue in the coming decades. By the mid-21st century, productivity may increase by as much as 30% of its current value in selected zones of arctic vegetation. 相似文献
34.
O. A. Anisimov E. L. Zhil&#;tsova K. O. Shapovalova A. A. Ershova 《Russian Meteorology and Hydrology》2020,45(1):13-21
Data on modern climate and environmental changes in the northwestern region of Russia are compared with the public perception of such changes. The analysis reveals that unusual weather patterns and single extreme events have a deeper impact on the public perception than long-term periods of climate change. The majority of population consider climate and environmental changes locally, do not associate them with global drivers, and are not prepared to adaptation. The numerical climate perception index is developed to characterize the awareness of population about the climate change and preparedness to adaptation. The index can be used for improving the awareness of policymakers for regional climate adaptation. 相似文献
35.
The permafrost regions currently occupy about one quarter of the Earth's land area.Climate-change scenarios indicate that global warming will be amplified in the polarregions, and could lead to a large reduction in the geographic extent of permafrost.Development of natural resources, transportation networks, and human infrastructurein the high northern latitudes has been extensive during the second half of the twentiethcentury. In areas underlain by ice-rich permafrost, infrastructure could be damagedseverely by thaw-induced settlement of the ground surface accompanying climatechange. Permafrost near the current southern margin of its extent is degrading, andthis process may involve a northward shift in the southern boundary of permafrostby hundreds of kilometers throughout much of northern North America and Eurasia.A long-term increase in summer temperatures in the high northern latitudes couldalso result in significant increases in the thickness of the seasonally thawed layerabove permafrost, with negative impacts on human infrastructure located on ice-richterrain. Experiments involving general circulation model scenarios of global climatechange, a mathematical solution for the thickness of the active layer, and digitalrepresentations of permafrost distribution and ice content indicates potential forsevere disruption of human infrastructure in the permafrost regions in response toanthropogenic climate change. A series of hazard zonation maps depicts generalizedpatterns of susceptibility to thaw subsidence. Areas of greatest hazard potential includecoastlines on the Arctic Ocean and parts of Alaska, Canada, and Siberia in whichsubstantial development has occurred in recent decades. 相似文献
36.
A method is proposed for calculating the effective thermal conductivity of snow cover based on the data on snow surface temperature and soil temperature measured at weather stations. The quantitative estimates of the snow cover effect on soil temperature are presented. The spatial differences in this effect are described. The results obtained significantly enhance the opportunities of applying simple models to forecast permafrost conditions under the climate change. 相似文献
37.
S. V. Anisimov S. V. Galichenko N. M. Shikhova 《Izvestiya Atmospheric and Oceanic Physics》2012,48(4):391-400
The dynamics of the electric field in the planetary boundary layer (PBL) is thoroughly studied from in situ observations of
the aeroelectric field and the height profiles of the wind-velocity components in the conditions of temperature inversion
and incipient convection. It is established that the formation of a layer with temperature inversion is accompanied by a positive
trend in the intensity of the aeroelectric field and by the generation of short-period aeroelectric pulsations. The transfer
of a spatially nonuniform space charge and the formation of electrically active layers in PBL are studied by numerical modeling.
The response of the electric field to the motion of the space charges simulating the coherent structures of electrogasdynamical
turbulence is investigated for the vicinity of the observation point. The key parameters of the model distributions of the
space charge are analyzed. The linear dimensions of the model structures range from 20 to 500 m, and the density of the transported
charge varies from 0.1 to 1 nC/m3. The layer containing the model structures is located at a height of 60–300 m. It is shown that the spatial distribution
and the transfer of the space charge form the dynamical component of the aeroelectric field in the surface layer. The short-period
aeroelectric pulsations are induced by the transfer of the spatially heterogeneous space charge in PBL, while the positive
trend is due to the accumulation of the space charge below the inversion layer. When the inversion was recorded by a sodar,
the intensity of the field at the onset of the convection increased at a rate of 100 V/(m h) on average. 相似文献
38.
The self-oscillation process of heat redistribution in the system ocean–atmosphere–continent should be considered as one of the mechanisms of multidecade climate variability. Based on the data of monitoring for the period 1960–2014, interdecadal variations in heat capacity in the upper active layer are estimated for the northwestern part of the Pacific Ocean, which is one of the most informative regions of the World Ocean. 相似文献
39.
S. V. Anisimov N. M. Shikhova N. G. Kleimenova 《Izvestiya Physics of the Solid Earth》2018,54(5):688-697
An algorithm is developed for automated detection of the short-period Pc1 geomagnetic pulsations (frequency band f = 0.2–3 Hz) from the continuous time series of digital recording during 1998–2014 at the midlatitude Borok station. A digital catalog with the indication of time intervals of the presence and main morphological characteristics of Pc1 pulsations is created. Based on this catalog, the annual, seasonal, and diurnal dynamics of the midlatitude Pc1 pulsation activity is studied for 1998–2014. It is shown that the annual variation of the Pc1 occurrence has a maximum in 2005, i.e., at the end of the solar cycle decay phase, just as in the previous cycles. It is found that the minimum of the cases of Pc1 occurrence is observed in 2009, i.e., not at the maximum, just was the case in the previous cycles, but during the deep minimum of solar activity, which testifies to the untypical conditions in the magnetosphere during the unusually long minimum of the 23rd cycle. The seasonal variation of the Pc1 occurrence has a summer minimum when the series of Pc1 pulsations occur almost thrice as rarely as in winter. Besides, there are relatively small maxima at equinox. The diurnal behavior of Pc1 pulsations has the maxima in the morning and midnight sectors of the magnetosphere. By the superposed epoch analysis technique it is established that the maximal number of the cases of occurrence of Pc1 pulsations at the Borok observatory is observed on the fourth day after the global geomagnetic disturbances. The statistical distributions of pulsations amplitude and duration are obtained. 相似文献
40.
O. A. Anisimov I. I. Borzenkova E. L. Zhil’tsova O. K. Zakharova V. A. Kokorev S. A. Reneva Yu. G. Strel’chenko 《Russian Meteorology and Hydrology》2011,36(5):307-314
The maps are presented of seasonal air temperature and precipitation amount anomalies averaged for the whole Volga region
and adjacent territory for two time periods, 1946–1977 and 1978–2008. It is demonstrated that the considerable differences
in the thermal and moistening regimes of the Volga region exist for these two periods. The relation is described between the
variations of temperature and precipitation amount and the circulation types according to Vangengeim-Girs classification as
well as the possibility to use these data for specifying the climatic scenarios obtained on the basis of physically complete
hydrodynamic models. 相似文献