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1.
Alexey V. Eliseev Pavel F. Demchenko Maxim M. Arzhanov Igor I. Mokhov 《Climate Dynamics》2014,42(5-6):1203-1215
Estimates of changes in near-surface permafrost (NSP) area S p relative to change in globally averaged surface air temperature T g are made by using the global climate model developed at the A.M. Obukhov Institute of Atmospheric Physics RAS (IAP RAS CM). For ensemble of runs forced by scenarios constructed as return-to-preindustrial continuations of the RCP (Representative Concentration Pathways) scenarios family, a possibility of transient hysteresis in dependence of S p versus T g is exhibited: in some temperature range which depends on imposed scenario of external forcing, NSP area is larger, at the same global mean surface air temperature, in a warming climate than in a cooling climate. This hysteresis is visible more clearly for scenarios with higher concentration of greenhouse gases in the atmosphere in comparison to those in which this concentration is lower. Hysteresis details are not sensitive to the type of the prescribed continuation path which is used to return the climate to the preindustrial state. The multiple-valued dependence of S p on T g arises due to dependence of soil state in the regions of extra-tropical wetlands and near the contemporary NSP boundaries on sign of external climatic forcing. To study the dependence of permafrost hysteresis on amplitude and temporal scale of external forcing, additional model runs are performed. These runs are forced by idealised scenarios of atmospheric CO2 content varying, depending on run, with periods from 100 to 1,000 year and with different amplitudes. It is shown that the above-mentioned hysteresis is related to the impact of phase transitions of soil water on apparent inertia of the system as well as to the impact of soil state on atmospheric hydrological cycle and radiation transfer in the atmosphere. 相似文献
2.
L. I. Shestakova B. I. Demchenko F. K. Rspaev A. Chalabaev 《Geomagnetism and Aeronomy》2011,51(8):1054-1057
The results of interferometer observations of the dust radial velocity field in the F-corona during the total solar eclipse
of March 29, 2006, are presented. The observations were performed in the Mugalzhar settlement, Aqtobe region, Kazakhstan.
The observation results indicated that the dust orbital motion is opposite to the planetary motion and is inclined at an angle
of about 105° with respect to the ecliptic plane. It is assumed that the observed dust is genetically related to Kreutz comets
falling on the Sun and registered with the SOHO spacecraft on March 28 and 31, 2006. 相似文献
3.
Changes in climatic characteristics of Northern Hemisphere extratropical land in the 21st century: Assessments with the IAP RAS climate model 总被引：1，自引：0，他引：1
A. V. Eliseev M. M. Arzhanov P. F. Demchenko I. I. Mokhov 《Izvestiya Atmospheric and Oceanic Physics》2009,45(3):271-283
Assessments of future changes in the climate of Northern Hemisphere extratropical land regions have been made with the IAP RAS climate model (CM) of intermediate complexity (which includes a detailed scheme of thermo- and hydrophysical soil processes) under prescribed greenhouse and sulfate anthropogenic forcing from observational data for the 19th and 20th centuries and from the SRES B1, A1B, and A2 scenarios for the 21st century. The annual mean warming of the extratropical land surface has been found to reach 2–5 K (3–10 K) by the middle (end) of the 21st century relative to 1961–1990, depending on the anthropogenic forcing scenario, with larger values in North America than in Europe. Winter warming is greater than summer warming. This is expressed in a decrease of 1–4 K (or more) in the amplitude of the annual harmonic of soil-surface temperature in the middle and high latitudes of Eurasia and North America. The total area extent of perennially frozen ground S p in the IAP RAS CM changes only slightly until the late 20th century, reaching about 21 million km2, and then decreases to 11–12 million km2 in 2036–2065 and 4–8 million km2 in 2071–2100. In the late 21st century, near-surface permafrost is expected to remain only in Tibet and in central and eastern Siberia. In these regions, depths of seasonal thaw exceed 1 m (2 m) under the SRES B1 (A1B or A2) scenario. The total land area with seasonal thaw or cooling is expected to decrease from the current value of 54–55 million km2 to 38–42 in the late 21st century. The area of Northern Hemisphere snow cover in February is also reduced from the current value of 45–49 million km2 to 31–37 million km2. For the basins of major rivers in the extratropical latitudes of the Northern Hemisphere, runoff is expected to increase in central and eastern Siberia. In European Russia and in southern Europe, runoff is projected to decrease. In western Siberia (the Ob watershed), runoff would increase under the SRES A1B and A2 scenarios until the 2050s–2070s, then it would decrease to values close to present-day ones; under the anthropogenic forcing scenario SRES B1, the increase in runoff will continue up to the late 21st century. Total runoff from Eurasian rivers into the Arctic Ocean in the IAP RAS CM in the 21st century will increase by 8–9% depending on the scenario. Runoff from the North American rivers into the Arctic Ocean has not changed much throughout numerical experiments with the IAP RAS CM. 相似文献
4.
Izvestiya, Atmospheric and Oceanic Physics - The anthropogenic impact on the Earth’s climate system is currently one of the main factors determining climate change over all spatial scales,... 相似文献
5.
We report the results of laboratory experiments on water heating/cooling, performed in 5 m long water channel with a slope.
About 63 series of photos were analyzed: for 3 locations, for 3 bottom slopes (3.7, 6.7 and 12 degrees) and for different
Ra numbers. It was pointed out that there exist two types of mixing characterizing different circulations in the presence of
slope: gravity current and undersurface jet; the thermal bar is the region where one type of mixing is replaced by another;
the highest speed and flowrate are at the break point; the flow is three-dimensional. 相似文献
6.
We have performed the calculations of the orbital evolution of dust particles from volcanic glass (p-obsidian), basalt, astrosilicate, olivine, and pyroxene in the sublimation zone near the Sun. The sublimation (evaporation) rate is determined by the temperature of dust particles depending on their radius, material, and distance to the Sun. All practically important parameters that characterize the interaction of spherical dust particles with the radiation are calculated using the Mie theory. The influence of radiation and solar wind pressure, as well as the Poynting–Robertson drag force effects on the dust dynamics, are also taken into account. According to the observations (Shestakova and Demchenko, 2016), the boundary of the dust-free zone is 7.0–7.6 solar radii for standard particles of the zodiacal cloud and 9.1–9.2 solar radii for cometary particles. The closest agreement is obtained for basalt particles and certain kinds of olivine, pyroxene, and volcanic glass. 相似文献
7.
A. V. Eliseev P. F. Demchenko M. M. Arzhanov I. I. Mokhov 《Doklady Earth Sciences》2012,444(2):725-728
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9.
P. F. Demchenko 《Izvestiya Atmospheric and Oceanic Physics》2012,48(2):143-151
Methods of stochastic dynamics based on the application of fluctuation theorems (FTs) are used for describing nonstationary
responses of natural objects to specified finite, but not necessarily small, changes in external factors in the presence of
random disturbances. Nonlinear fluctuation-dissipation relationships (FDRs) are obtained on the basis of one of the FTs. These
FDRs are used for calculating the soil moisture content response to specified changes in the mean precipitation in the presence
of synoptic disturbances. The model under consideration, in spite of its coarseness, includes an important nonlinear effect
of the moisture excess discharge into a reservoir. An approximate analytical theory is constructed. This theory makes it possible
to take into account nonlinear effects when response functions are determined. 相似文献
10.
In the 21st century, the climate of expanding megacities and urbanized areas is increasingly forming and changing under the influence of the growing power consumption of the urban economy. To understand the urban climate dynamic and estimate the energy needs of cities in the 21st century, it is necessary to consider not only global and regional climatic factors, but also the presence of feedback between temperature and energy consumption in urbanized areas. This feedback can be both negative and positive, and their significance depends essentially on the climate and landform of the region, system of electricity and heat supply of a city, and some other factors. This article describes the main factors of formation and development of temperature and energy-consumption feedback within urbanized areas in cold and warm seasons when indoor heating or air conditioning is being used. The role of advection in strengthening and weakening of this feedback is studied. The estimates of the parameter and coefficient of feedback strengthening with the influence of anthropogenic heat fluxes and advection on the urban air temperature are presented. 相似文献