Труды сотрудников ИВМ СО РАН

/ C. J. Farrugia [et al.] // J. Atmos. Sol.-Terr. Phys. - 2013. - Vol. 99. - P14-26, DOI 10.1016/j.jastp.2012.11.014. - Cited References: 53. - C.J.F. is supported by NASA Grant NNX10AQ29G and NSF Grant AGS-1140211. N.V.E. acknowledges support from Austrian Science Fund Project I193-N16 and RFBR Grant no 12-05-00152-a. N.L. acknowledges support from NSF Grant AGS-1140211. Work at LANL was conducted under the auspices of the U.S. Department of Energy with partial support from NASA and NSF. . - 13. - ISSN 1364-6826РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: The interaction of interplanetary coronal mass ejections (ICMEs) and magnetic clouds (MCs) with the Earth's magnetosphere exhibits various interesting features principally due to interplanetary parameters which change slowly and reach extreme values of long duration. These, in turn, allow us to explore the geomagnetic response to continued and extreme driving of the magnetosphere. In this paper we shall discuss elements of the following: (i) anomalous features of the flow in the terrestrial magnetosheath during ICME/MC passage and (ii) large geomagnetic disturbances when total or partial mergers of ICMEs/MCs pass Earth. In (i) we emphasize two roles played by the upstream Alfven Mach number in solar wind-magnetosphere interactions: (i) It gives rise to wide plasma depletion layers. (ii) It enhances the magnetosheath flow speed on draped magnetic field lines. (By plasma depletion layer we mean a magnetosheath region adjacent to the magnetopause where magnetic forces dominate over hydrodynamic forces.) In (ii) we stress that the ICME mergers elicit geoeffects over and above those of the individual members. In addition, features of the non-linear behavior of the magnetosphere manifest themselves. (C) 2012 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Farrugia, C.J.; Erkaev, N.V.; Еркаев, Николай Васильевич; Jordanova, V.K.; Lugaz, N.; Sandholt, P.E.; Muhlbachler, S.; Torbert, R.B.

[Text] / U.V. Amerstorfer [et al.] // Phys. Plasmas. - 2010. - Vol. 17, Is. 7. - Ст. 72901, DOI 10.1063/1.3453705. - Cited References: 26. - This work was supported by the FWF under Project No. P21051-N16 and also by the RFBR under Grant No. 09-05-91000-ANF_a. . - ISSN 1070-664XРУБ Physics, Fluids & Plasmas

Аннотация: Results of two-dimensional nonlinear numerical simulations of the magnetohydrodynamic Kelvin-Helmholtz instability are presented. A boundary layer of a certain width is assumed, which separates the plasma in the upper layer from the plasma in the lower layer. A special focus is given on the influence of a density increase toward the lower layer. The evolution of the Kelvin-Helmholtz instability can be divided into three different phases, namely, a linear growth phase at the beginning, followed by a nonlinear phase with regular structures of the vortices, and finally, a turbulent phase with nonregular structures. The spatial scales of the vortices are about five times the initial width of the boundary layer. The considered configuration is similar to the situation around unmagnetized planets, where the solar wind (upper plasma layer) streams past the ionosphere (lower plasma layer), and thus the plasma density increases toward the planet. The evolving vortices might detach around the terminator of the planet and eventually so-called plasma clouds might be formed, through which ionospheric material can be lost. For the special case of a Venus-like planet, loss rates are estimated, which are of the order of estimated loss rates from observations at Venus. (C) 2010 American Institute of Physics. [doi:10.1063/1.3453705]


Доп.точки доступа:
Amerstorfer, U.V.; Erkaev, N.V.; Еркаев, Николай Васильевич; Taubenschuss, U.; Biernat, H.K.

[Text] / U. Taubenschuss [et al.] // Ann. Geophys. - 2010. - Vol. 28, Is. 5. - pp. 1075-1100, DOI 10.5194/angeo-28-1075-2010. - Cited References: 92. - The author appreciates financial support on behalf of the projects 06/9690 from the Austrian Research Community and A3-12T63/2007-1 from the Styrian government. Participation at the ISSS8 was made possible due to the travel fellowship of UCLA. Nikolai Erkaev acknowledges support by RFBR grants Nos. 07-05-00135 and 09-05-91000-ANF. Charles Farrugia received NASA grants NNG06GD41G and NNX08AD11G. Christian Mostl and Ute Amerstorfer work under FWF projects P20145N16 and P21051-N16 of the Austrian Science Foundation, respectively. . - ISSN 0992-7689РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: We investigate the propagation of magnetic clouds (MCs) through the inner heliosphere using 2.5-D ideal magnetohydrodynamic (MHD) simulations. A numerical solution is obtained on a spherical grid, either in a meridional plane or in an equatorial plane, by using a Roe-type approximate Riemann solver in the frame of a finite volume approach. The structured background solar wind is simulated for a solar activity minimum phase. In the frame of MC propagation, special emphasis is placed on the role of the initial magnetic handedness of the MC's force-free magnetic field because this parameter strongly influences the efficiency of magnetic reconnection between the MC's magnetic field and the interplanetary magnetic field. Magnetic clouds with an axis oriented perpendicular to the equatorial plane develop into an elliptic shape, and the ellipse drifts into azimuthal direction. A new feature seen in our simulations is an additional tilt of the ellipse with respect to the direction of propagation as a direct consequence of magnetic reconnection. During propagation in a meridional plane, the initial circular cross section develops a concave-outward shape. Depending on the initial handedness, the cloud's magnetic field may reconnect along its backside flanks to the ambient interplanetary magnetic field (IMF), thereby losing magnetic flux to the IMF. Such a process in combination with a structured ambient solar wind has never been analyzed in detail before. Furthermore, we address the topics of force-free magnetic field conservation and the development of equatorward flows ahead of a concave-outward shaped MC. Detailed profiles are presented for the radial evolution of magnetoplasma and geometrical parameters. The principal features seen in our MHD simulations are in good agreement with in-situ measurements performed by spacecraft. The 2.5-D studies presented here may serve as a basis under more simple geometrical conditions to understand more complicated effects seen in 3-D simulations.


Доп.точки доступа:
Taubenschuss, U.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Farrugia, C.J.; Mostl, C.; Amerstorfer, U.V.

/ K. G. Kislyakova [et al.] // Astrobiology. - 2013. - Vol. 13, Is. 11. - P1030-1048, DOI 10.1089/ast.2012.0958 . - ISSN 1531-1074
Аннотация: We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a "super-Earth" with a radius of 2 R Earth and a mass of 10 MEarth, located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×1025 s-1 to ∼5.3×1030 s-1, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EOH) to <3 EOH and usually is several times smaller in comparison to the thermal atmospheric escape rates. © 2013 Mary Ann Liebert, Inc.

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Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, A-8042 Graz, Austria
Institute of Physics, University of Graz, Graz, Austria
Swedish Institute of Space Physics, Kiruna, Sweden
Institute of Computational Modelling, Siberian Division of the Russian Academy of Sciences, Krasnoyarsk, Russian Federation
SINP, Moscow State University, Moscow, Russian Federation
Polar Geophysical Institute (PGI), Russian Academy of Sciences, Murmansk, Russian Federation
Institute of Astrophysics, University of Vienna, Austria
ИВМ СО РАН

Доп.точки доступа:
Kislyakova, K.G.; Lammer, H.; Holmstrom, M.; Panchenko, M.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Leitzinger, M.; Khodachenko, M.L.; Kulikov, Y.N.; Gudel, M.; Hanslmeier, A.

[Text] / T. Penz [et al.] ; ed.: O. Witasse // PLANETARY ATMOSPHERES, IONOSPHERES, AND MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE LTD, 2005. - Vol. 36: 35th COSPAR Scientific Assembly (JUL 18-25, 2004, Paris, FRANCE), Is. 11. - P2049-2056, DOI 10.1016/j.asr.2004.11.039. - Cited References: 20 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: It is known from Pioneer Venus measurements that at the Venusian ionopause wave-like structures develop, which can detach in the form of ionospheric plasma clouds. This phenomenon is assumed to occur due to the Kelvin-Helmholtz instability, which can appear in large regions of the Venusian ionopause. Recent studies of Mars Global Surveyor measurements indicate that wave-like structures and plasma clouds also detach from the Martian ionopause. Therefore, these features seem to be common for the solar wind interaction of non-magnetized planets. We study the conditions at the Martian ionopause with respect to the occurrence of several MHD instabilities. The conditions in the magnetosheath are modeled by a semi-analytical MHD simulation that includes mass loading. The ionospheric parameter needed for the model calculations are taken from a global hybrid model. The stability of the Martian ionopause against the Kelvin-Helmholtz, the Rayleigh-Taylor, and the interchange instability is analyzed. Further, we suggest that including the Hall term in the description of the Kelvin-Helmholtz instability gives a current in the planetary boundary layer resulting in a shear flow compared with the ionospheric plasma, which can lead to an unstable boundary layer near the subsolar point. Since the interchange instability depends on the curvature of the magnetic field lines, we additionally study the influence of the strong curvature of the Martian ionopause due to the localized, remnant, crustal magnetism appearing mainly in the southern hemisphere of Mars. (c) 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Penz, T.; Arshukova, I.L.; Terada, N.; Shinagawa, H.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Lammer, H.; Witasse, O. \ed.\

[Text] / T. Penz [et al.] // Planet Space Sci. - 2004. - Vol. 52, Is. 13. - P1157-1167, DOI 10.1016/j.pss.2004.06.001. - Cited References: 53 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: Mars Global Surveyor detected cold electrons above the Martian ionopause, which can be interpreted as detached ionospheric plasma clouds. Similar observations by the Pioneer Venus Orbiter electron temperature probe showed also extreme spatial irregularities of electrons in the form of plasma clouds on Venus, which were explained by the occurrence of the Kelvin-Helmholtz instability. Therefore, we suggest that the Kelvin-Helmholtz instability may also detach ionospheric plasma clouds on Mars. We investigate the instability growth rate at the Martian ionopause resulting from the flow of the solar wind for the case where the interplanetary magnetic field is oriented normal to the flow direction. Since the velocity shear near the subsolar point is very small, this area is stable with respect to the Kelvin-Helmholtz instability. We found that the highest flow velocities are reached at the equatorial flanks near the terminator plane, while the maximum plasma density in the terminator plane appears at the polar areas. By comparing the instability growth rate with the magnetic barrier formation time, we found that the instability can evolve into a non-linear stage at the whole terminator plane but preferably at the equatorial flanks. Escape rates of O+ ions due to detached plasma clouds in the order of about 2 x 10(23)-3 x 10(24) s(-1) are found. Thus, atmospheric loss caused by the Kelvin-Helmholtz instability should be comparable with other non-thermal loss processes. Further, we discuss our results in view of the expected observations of heavy ion loss rates by ASPERA-3 on board of Mars Express. (C) 2004 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Penz, T.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Lammer, H.; Amerstorfer, U.V.; Gunell, H.; Kallio, E.; Barabash, S.; Orsini, S.; Milillo, A.; Baumjohann, W.

[Text] / H. Lammer [et al.] // Planet Space Sci. - 2006. - Vol. 54, Is. 13-14. - P1445-1456, DOI 10.1016/j.pss.2006.04.022. - Cited References: 93 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: Atmospheric escape from the upper atmosphere of Venus is mainly influenced by the loss of hydrogen and oxygen caused by the interaction of solar radiation and particle flux with the unprotected planetary environment. Because one main aim of the ASPERA-4 particle/plasma and VEX-MAG magnetic field experiments on board of ESA's forthcoming Venus Express mission is the investigation of atmospheric erosion processes from the planet's ionosphere-exosphere environment, we study the total loss of hydrogen and oxygen and identified the efficiency of several escape mechanisms involved. For the estimation of pick up loss rates we use a gas dynamic test particle model and obtained average loss rates for H+, and O+ pick up ions of about 1 x 10(25) s(-1) and about 1.6 x 10(25) s(-1), respectively. Further, we estimate ion loss rates due to detached plasma clouds, which were observed by the pioneer Venus orbiter and may be triggered by the Kelvin-Helmholtz instability of about 0.5-1 x 10(25) s(-1). Thermal atmospheric escape processes and atmospheric loss by photo-chemically produced oxygen atoms yield negligible loss rates. Sputtering by incident pick up O+ ions give O atom loss rates in the order of about 6 x 10(24) s(-1). On the other hand, photo-chemically produced hot hydrogen atoms are a very efficient loss mechanism for hydrogen on Venus with a global average total loss rate of about 3.8 x 10(25) s(-1), which is in agreement with Donahue and Hartle [1992. Solar cycle variations in H+ and D+ densities in the Venus ionosphere: implications for escape. Geophys. Res. Lett. 12, 2449-2452] and of the same order but less than the estimated H+ ion outflow on the Venus nightside of about 7.0 x 10(25) s(-1) due to acceleration by an outward electric polarization force related to ionospheric holes by Hartle and Grebowsky [1993. Light ion flow in the nightside ionosphere of Venus. J. Geophys. Res. 98, 7437-7445]. Our study indicates that on Venus, due to its larger mass and size compared to Mars, the most relevant atmospheric escape processes of oxygen involve ions and are caused by the interaction with the solar wind. The obtained results indicate that the ratio between H/O escape to space from the Venusian upper atmosphere is about 4, and is in a much better agreement with the stoichiometrically H/O escape ratio of 2:1, which is not the case on Mars. However, a detailed analysis of the outflow of ions from the Venus upper atmosphere by the ASPERA-4 and VEX-MAG instruments aboard Venus Express will lead to more accurate atmospheric loss estimations and a better understanding of the planet's water inventory. (c) 2006 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Lammer, H.; Lichtenegger, H.I.M.; Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Arshukova, I.L.; Kolb, C.; Gunell, H.; Lukyanov, A.; Holmstrom, M.; Barabash, S.; Zhang, T.L.; Baumjohann, W.

[Text] / U. V. Mostl [et al.] // Icarus. - 2011. - Vol. 216, Is. 2. - P476-484, DOI 10.1016/j.icarus.2011.09.012. - Cited References: 27. - This work is supported by the Austrian Science Fund Project P21051-N16 and also by RFBR Grant No. 09-05-91000-ANF_a. H.L. and H.G. are supported by the Helmholtz Association through the research alliance "Planetary Evolution and Life" and by the Austrian Science Fund Project I199-N16. M.Z. and D.K. are supported by the Austrian Science Fund Project I193-N16. . - ISSN 0019-1035РУБ Astronomy & Astrophysics

Аннотация: The Kelvin-Helmholtz instability gained scientific attention after observations at Venus by the spacecraft Pioneer Venus Orbiter gave rise to speculations that the instability contributes to the loss of planetary ions through the formation of plasma clouds. Since then, a handful of studies were devoted to the Kelvin-Helmholtz instability at the ionopause and its implications for Venus. The aim of this study is to investigate the stability of the two instability-relevant boundary layers around Venus: the induced magnetopause and the ionopause. We solve the 2D magnetohydrodynamic equations with the total variation diminishing Lax-Friedrichs algorithm and perform simulation runs with different initial conditions representing the situation at the boundary layers around Venus. Our results show that the Kelvin-Helmholtz instability does not seem to be able to reach its nonlinear vortex phase at the ionopause due to the very effective stabilizing effect of a large density jump across this boundary layer. This seems also to be true for the induced magnetopause for low solar activity. During high solar activity, however, there could occur conditions at the induced magnetopause which are in favour of the nonlinear evolution of the instability. For this situation, we estimated roughly a growth rate for planetary oxygen ions of about 7.6 x 10(25) s(-1), which should be regarded as an upper limit for loss due to the Kelvin-Helmholtz instability. (C) 2011 Elsevier Inc. All rights reserved.


Доп.точки доступа:
Mostl, U.V.; Erkaev, N.V.; Еркаев, Николай Васильевич; Zellinger, M.; Lammer, H.; Groller, H.; Biernat, H.K.; Korovinskiy, D.

/ H. Lammer [et al.] // Mon. Not. R. Astron. Soc. Lett. - 2016. - Vol. 461, Is. 1. - PL62-L66, DOI 10.1093/mnrasl/slw095 . - ISSN 1745-3925
Аннотация: For the hot exoplanets CoRoT-24b and CoRoT-24c, observations have provided transit radii RT of 3.7 ± 0.4R? and 4.9 ± 0.5R?, and masses of ?5.7M? and 28 ± 11M?, respectively. We study their upper atmosphere structure and escape applying an hydrodynamic model. Assuming RT ? RPL, where RPL is the planetary radius at the pressure of 100 mbar, we obtained for CoRoT-24b unrealistically high thermally driven hydrodynamic escape rates. This is due to the planet's high temperature and low gravity, independent of the stellar EUV flux. Such high escape rates could last only for <100 Myr, while RPL shrinks till the escape rate becomes less than or equal to the maximum possible EUV-driven escape rate. For CoRoT-24b, RPL must be therefore located at ?1.9-2.2R? and high altitude hazes/clouds possibly extinct the light at RT. Our analysis constraints also the planet's mass to be 5-5.7M?. For CoRoT-24c, RPL and RT lie too close together to be distinguished in the same way. Similar differences between RPL and RT may be present also for other hot, low-density sub-Neptunes. © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

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Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, Graz, Austria
Institute of Computational Modelling SB RAS, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation
Thuringer Landessternwarte Tautenburg, Sternwarte 5, Tautenburg, Germany
Institute for Astronomy, University of Vienna, Turkenschanzstrasse 17, Vienna, Austria

Доп.точки доступа:
Lammer, H.; Erkaev, N. V.; Fossati, L.; Juvan, I.; Odert, P.; Cubillos, P. E.; Guenther, E.; Kislyakova, K. G.; Johnstone, C. P.; Luftinger, T.; Gudel, M.

/ P. Cubillos [et al.] // Mon. Not. Roy. Astron. Soc. - 2017. - Vol. 466, Is. 2. - P1868-1879, DOI 10.1093/mnras/stw3103. - Cited References:107. - We thank contributors to SCIPY, MATPLOTLIB (Hunter 2007), the PYTHON programming language, and contributors to the free and open-source community. We thank the anonymous referee for comments that significantly improved the quality of the paper. This research has made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at exoplanets.org and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. We acknowledge the Austrian Forschungsforderungsgesellschaft FFG projects 'RASEN' P847963 and 'TAPAS4CHEOPS' P853993, the Austrian Science Fund (FWF) National Research Network projects S11607-N16 and S11604-N16, and the FWF project P27256-N27. NVE acknowledges support by the Russian Foundation for Basic Research grant no. 15-05-00879-a and no. 16-52-14006 ANF-a. . - ISSN 0035-8711. - ISSN 1365-2966РУБ Astronomy & Astrophysics

Аннотация: We present a uniform analysis of the atmospheric escape rate of Neptune-like planets with estimated radius and mass (restricted to M-p < 30M(circle plus)). For each planet, we compute the restricted Jeans escape parameter, Lambda, for a hydrogen atom evaluated at the planetary mass, radius, and equilibrium temperature. Values of Lambda less than or similar to 20 suggest extremely high mass-loss rates. We identify 27 planets (out of 167) that are simultaneously consistent with hydrogen-dominated atmospheres and are expected to exhibit extreme mass-loss rates. We further estimate the mass-loss rates (L-hy) of these planets with tailored atmospheric hydrodynamic models. We compare L-hy to the energy-limited (maximum-possible high-energy driven) mass-loss rates. We confirm that 25 planets (15 per cent of the sample) exhibit extremely high mass-loss rates (L-hy > 0.1M(circle plus) Gyr(-1)), well in excess of the energy-limited mass-loss rates. This constitutes a contradiction, since the hydrogen envelopes cannot be retained given the high mass-loss rates. We hypothesize that these planets are not truly under such high mass-loss rates. Instead, either hydrodynamic models overestimate the mass-loss rates, transit-timing-variation measurements underestimate the planetary masses, optical transit observations overestimate the planetary radii (due to high-altitude clouds), or Neptunes have consistently higher albedos than Jupiter planets. We conclude that at least one of these established estimations/ techniques is consistently producing biased values for Neptune planets. Such an important fraction of exoplanets with misinterpreted parameters can significantly bias our view of populations studies, like the observed mass-radius distribution of exoplanets for example.

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Держатели документа:
Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
SB RAS, Krasnoyarsk Sci Ctr, Fed Res Ctr, Inst Computat Modelling, Krasnoyarsk 660036, Russia.
Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.

Доп.точки доступа:
Cubillos, Patricio; Erkaev, N.V.; Еркаев, Николай Васильевич; Juvan, Ines; Fossati, Luca; Johnstone, Colin P.; Lammer, Helmut; Lendl, Monika; Odert, Petra; Kislyakova, Kristina G.; Austrian Forschungsforderungsgesellschaft FFG [P847963, P853993]; Austrian Science Fund (FWF) National Research Network projects [S11607-N16, S11604-N16]; FWF [P27256-N27]; Russian Foundation for Basic Research [15-05-00879-a, 16-52-14006 ANF-a]

[Text] : доклад, тезисы доклада / S. I. Bartsev, P. V. Belolipetsky, M. Y. Saltykov // 15th International Conference on Environmental Science and Technology (CEST 2017) : proceedings of the 15th International Conference on Environmental Science and Technology (CEST 2017). - Rhodes : Global Network for Environmental Science and Technology, 2017. - Ст. 01013
Аннотация: Time series analysis of global temperature and ~70 other global and local parameters indicates the presence of abrupt shifts between stationary states. The concept of non-linear systems, which undoubtedly include the "biosphere-climate" system, makes the threshold response to gradually increasing influence factor (the increase in greenhouse gas concentrations) quite expectable. Quasi-stable regimes taking place between the shifts presume the existence of some regulation mechanism which can maintain global temperature near constant in the presence of changing external forcing.Some authors suggest regulation of surface temperatures by clouds. Understanding the nature of such shifts and stationary regimes between them at qualitative concepts can be achieved by using conceptual small-scale models. In the paper some phenomenological extension of Lorenz-84 Model devoted to low order description of atmospheric circulation accounting possible clouds feedback was considered. It was shown the model itself is able to reduce the effect of forcing changes. Involving clouds feedback increases the resistance of the model to external disturbances

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Держатели документа:
Institute of Biophysics, SB RAS
Institute of Computational Modelling, SB RAS

Доп.точки доступа:
Bartsev, S.I.; Belolipetsky, P.V.; Saltykov, M.Y.; 15th International Conference on Environmental Science and Technology (CEST 2017)(2017 ; 31.08 - 02.09 ; Rhodes)
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[Text] : доклад, тезисы доклада / M. Saltykov [et al.] // 15th International Conference on Environmental Science and Technology (CEST 2017) : proceedings of the 15th International Conference on Environmental Science and Technology (CEST 2017). - Rhodes : Global Network for Environmental Science and Technology, 2017. - Ст. 00684
Аннотация: Outgoing long-wave radiation (OLR) has increased substantially over the period 1979 to 2016. In time series averaged for northern and southern mid-latitudes two abrupt, synchronous and statistically significant step-like shifts (1988 and 1997/8) are shown to have occurred with only one shift in the tropics (1997). The timing of these events coincides with similar shifts recently described in a wide range of climate, Earth system and ecological time series. Surface temperature shows a very similar pattern of change to OLR in the northern mid-latitudes, but differs considerably in the southern mid-latitude belt. We demonstrate that low clouds are positively correlated with OLR and the reverse with medium and high clouds confirming that the growth in OLR can be explained via a reduction in cloud cover and atmospheric albedo

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Emeriti of Eawag, Swiss Federal Institute of Aquatic Science and Technology, ?CH-8600 Duebendorf, Switzerland
Institute of Biophysics, SB RAS
Institute of Computational Modelling, SB RAS
Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
Marine Institute, Plymouth University, Drake Circus, Plymouth PL4 8AA, UK
Sir Alister Hardy Foundation for Ocean Science, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK

Доп.точки доступа:
Saltykov, M.; Belolipetsky, P.; Hari, R.E.; Reid, P.C.; Bartsev, S.; 15th International Conference on Environmental Science and Technology (CEST 2017)(2017 ; 31.08 - 02.09 ; Rhodes)
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