Am Obukhov Institute Of Atmospheric Physics

Moscow, Russia

Am Obukhov Institute Of Atmospheric Physics

Moscow, Russia

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Polyakov I.V.,University of Alaska Fairbanks | Alexeev V.A.,University of Alaska Fairbanks | Ashik I.M.,Arctic and Antarctic Research Institute | Bacon S.,UK National Oceanography Center | And 17 more authors.
Bulletin of the American Meteorological Society | Year: 2011

Observations show the warm pulse of Atlantic Water (AW) that entered the Arctic Ocean in the early 1990s has reached the Canada Basin during the 2000s. Observations from 2008-09 suggest that the recent warm surge has passed its peak in the Eurasian Basin, Data show apparently synchronous warming of the AW and the overlying layer (OL) at 125°E, which is consistent with a rapid communication of heat between the AW and the OL. Data from the West Spitsbergen Current showed that intensive AW warming culminated in 2006 with AW temperature anomalies up to 1.2°C in the vicinity of Svalbard. Coherent changes in local atmospheric and oceanic thermodynamic forcing and multiyear ice coverage suggest a plausible role of anomalous oceanic heat in recent changes of the Arctic ice cover. Indications of an increasing role for both local atmosphere-ocean and shelf-basin interactions is also clear.


Akperov M.,Am Obukhov Institute Of Atmospheric Physics | Mokhov I.,Am Obukhov Institute Of Atmospheric Physics | Rinke A.,Alfred Wegener Institute for Polar and Marine Research | Dethloff K.,Alfred Wegener Institute for Polar and Marine Research | Matthes H.,Alfred Wegener Institute for Polar and Marine Research
Theoretical and Applied Climatology | Year: 2014

Characteristics of cyclones (frequency, intensity and size) and their changes in the Arctic region in a warmer climate have been analyzed with the use of the HIRHAM regional climate model simulations with SRES-A1B anthropogenic scenario for the twenty first century. The focus was on cyclones for the warm (April–September) and cold (October–March) seasons. The present-day cyclonic characteristics from HIRHAM simulations are in general agreement with those from ERA–40 reanalysis data. Differences noted for the frequency of cyclones are related with different spatial resolution in the model simulations and reanalysis data. Potential future changes in cyclone characteristics at the end of the twenty first century have been analyzed. According to the model simulations, the frequency of cyclones is increasing in warm seasons and decreasing in cold seasons for a warmer climate in the twenty first century, but these changes are statistically insignificant. Noticeable changes were detected for the intensity and size of cyclones for the both seasons. Significant increase was found for the frequency of weak cyclones during cold season. Further, a general increase in the frequency of small cyclones was calculated in cold seasons, while its frequency decreases in warm seasons. © 2014 Springer-Verlag Wien


Kouznetsov R.,Finnish Meteorological Institute | Kouznetsov R.,Am Obukhov Institute Of Atmospheric Physics | Tisler P.,Finnish Meteorological Institute | Palo T.,Finnish Meteorological Institute | And 2 more authors.
Journal of Applied Meteorology and Climatology | Year: 2013

The three-axis "Latan-3" Doppler sodar was operated near the Finnish Antarctic station Aboa in Dronning Maud Land (73.048S, 13.408W) in the austral summer of 2010/11. Themeasuring site is located at a practically flat, slightly sloped (about1%) surface of the glacier. The sodar was operated inmultiple-frequency parallelmode with 20-800-m sounding range, 20-m vertical resolution, and 10-s temporal resolution. To reveal the wind and temperature profiles below the sounding range as well as turbulent fluxes at 2 and 10 m, the data from a 10-m meteorological mast were used. During the measurements, the atmospheric boundary layer was within the sounding range of the sodar most of the time. Despite a large variety of observed sodar echo patterns and wind speed profiles, several cases of clear steady katabatic flows were observed. Practically all of them were easterly, whereas the uphill direction is southern. The thickness of the katabatic flow varied from a few tens to several hundreds of meters; the wind speed maximum could be as low as 5 m. Thin katabatic flows had lower wind speed and much stronger temperature gradients (up to 1 K m-1) but had smaller surface heat flux than did the thicker ones. © 2013 American Meteorological Society.


Zilitinkevich S.S.,Finnish Meteorological Institute | Zilitinkevich S.S.,Gc Rieber Climate Institute | Zilitinkevich S.S.,Helsinki Institute of Physics | Esau I.,Gc Rieber Climate Institute | And 5 more authors.
Boundary-Layer Meteorology | Year: 2010

We give a new derivation of the familiar linear relation for the dimensionless velocity gradient in the stably stratified surface layer and provide physical and empirical grounds for its universal applicability in stationary homogeneous turbulence over the whole range of static stabilities from Ri = 0 to very large Ri. Combining this relation with the budget equation for the turbulent kinetic energy we obtain the "equilibrium formulation" of the turbulent dissipation length scale, and recommend it for use in turbulence closure models. © The Author(s) 2010.


Logofet D.O.,Am Obukhov Institute Of Atmospheric Physics
Ecological Complexity | Year: 2013

Linear matrix models of stage-structured population dynamics are widely used in plant and animal demography as a tool to evaluate the growth potential of a population in a given environment. The potential is identified with λ1, the dominant eigenvalue of the projection matrix, which is compiled of stage-specific transition and fertility rates. Advanced botanical studies reveal polyvariant ontogeny in perennial plants, i.e., multiple different versions of individual development within a local population of a single species. This phenomenon complicates any standard, successive-stage, life cycle graph to a digraph defined on a 2D lattice in the age and stage dimensions, the pattern of projection matrix becoming more complex too. In a kind of experimental design, the transition rates can be calculated directly from the data for two successive time moments, but the age-stage-specific rates of reproduction still remain uncertain, adding more complexity to the calibration problem. Simple additional assumptions could technically eliminate the uncertainty, but they contravene the biology of a species in which polyvariant ontogeny is considered to be the major mechanism of adaptation. Given the data and expert constraints, the calibration can be reduced instead to a nonlinear maximization problem, yet with linear constraints. I prove that it has a unique solution to be attained at a vertex of the constraint polyhedral. To facilitate searching for the solution in practice, I use the net reproductive rate R0, a well-known indicator for the principal property of λ1 to be greater or less than 1. The method is exemplified with the calibration of a projection matrix in an age-stage-structured model (published elsewhere) for Calamagrostis canescens, a perennial herbaceous species with a complex (multivariant) life cycle that features unlimited growth when colonizing open areas. © 2013 Elsevier B.V.


Kallistratova M.A.,Am Obukhov Institute Of Atmospheric Physics | Kouznetsov R.D.,Finnish Meteorological Institute
Boundary-Layer Meteorology | Year: 2012

We evaluate the statistical properties of low-level jets (LLJs) observed by means of a network of Doppler sodars in the Moscow region, Russia. Continuous long-term measurements of the echo-signal intensity and wind-velocity profiles were carried out in July 2005 and in 2008-2010 synchronously in the centre of Moscow and at a rural site. The summertime nocturnal LLJs have a very clear diurnal cycle and exhibit features predicted by the Blackadar mechanism. In contrast, the long-lasting wintertime jets do not have any clear diurnal variability. The urban environment strongly influences LLJs in both seasons: above the city LLJs are higher, weaker and observed more rarely than at the rural site. In very cold periods (air temperature below -8°C) no LLJs were observed over the city, instead convection emerged in the urban boundary layer. The results are based on observations made in July 2005, January and December 2009, and January 2011. © 2011 Springer Science+Business Media B.V.


Gruzdev A.N.,Am Obukhov Institute Of Atmospheric Physics | Elokhov A.S.,Am Obukhov Institute Of Atmospheric Physics
International Journal of Remote Sensing | Year: 2010

We present the results of comparison between Ozone Monitoring Instrument (OMI) data of NO2 measurements (Collection 3) onboard the NASA EOS-Aura satellite and correlative ground-based twilight measurements at Zvenigorod station in Russia in 2004-2008. Compared quantities are unpolluted column and tropospheric column amounts of NO2 which are standard products of OMI measurements. The NO2 columns observed by our ground-based instrument have been interpolated to the time of OMI measurements using a one-dimensional photochemical model. According to our comparison, the OMI unpolluted NO2 columns underestimate ground-based measurements by (0.084 ± 0.025) × 1015 molecules/cm2, or (3.2 ± 0.9)%. The correlation coefficient between the OMI and ground-based unpolluted NO2 columns is 0.92. The tropospheric NO2 columns derived from OMI measurements are on average by (1.8 ± 0.5) × 1015 cm-2, or approximately 40%, less than those derived from ground-based measurements. The correlation coefficient between these data is about 0.3. Reasons for this discrepancy are discussed. © 2010 Taylor & Francis.


Salazar R.,University of Concepción | Kurgansky M.V.,University of Concepción | Kurgansky M.V.,AM Obukhov Institute of Atmospheric Physics
Journal of Physics A: Mathematical and Theoretical | Year: 2010

Concrete examples of the construction of Nambu brackets for equations of motion (both 3D and 2D) of Boussinesq stratified fluids and also for magnetohydrodynamical equations are given. It serves a generalization of Hamiltonian formulation for the considered equations of motion. Two alternative Nambu formulations are proposed, first by using fluid dynamical (kinetic) helicity and/or enstrophy as constitutive elements and second, by using the existing conservation laws of the governing equation. © 2010 IOP Publishing Ltd.


Lyulyukin V.,Am Obukhov Institute Of Atmospheric Physics | Kouznetsov R.,Finnish Meteorological Institute | Kallistratova M.,Am Obukhov Institute Of Atmospheric Physics
Journal of Atmospheric and Oceanic Technology | Year: 2013

The structure and dynamic characteristics of the Kelvin-Helmholtz billows (KHB), observed with a sodar in the stable atmospheric boundary layer, are studied by means of composite analysis, which consists in the averaging of samples selected according to certain criteria. Using a specific kind of this method allowed the authors to obtain the fine structure of the perturbation velocity fields from the sodar data. The events of most pronounced KHB were visually selected from echograms of continuous sodar measurements in the Moscow region over 2008-10. The composite patterns of KHB have been constructed for a few cases of clear inclined- stripes echogram patterns to derive a typical finescale structure of billows and a spatial distribution of wind speed and shear within them. The interconnection between echo intensity and wind shear variations within such patterns is shown. The typical distributions of velocity perturbation within various forms of billows are found. © 2013 American Meteorological Society.


Gruzdev A.N.,Am Obukhov Institute Of Atmospheric Physics | Elokhov A.S.,Am Obukhov Institute Of Atmospheric Physics
International Journal of Remote Sensing | Year: 2011

We present an analysis of the results of measurements of nitrogen dioxide (NO2) content at the Zvenigorod Research Station of the A.M. Obukhov Institute of Atmospheric Physics, which is located 50 km west of Moscow. Systematic NO2 observations at Zvenigorod started in 1990 and are carried out with a zenith viewing grating spectrophotometer in the 435-450 nm wavelength range during morning and evening twilight. Measurements within a wide range of air-mass factors allow the retrieval of vertical profiles of NO2 and the determination of stratospheric and tropospheric NO2 content. Analysis shows that stratospheric and boundary-layer NO2 exhibit very different temporal behaviours. Stratospheric NO2 undergoes very prominent and regular diurnal and annual cycles associated with photochemical processes, as well as less regular intra-annual and inter-annual variations. Boundary-layer NO2 is very changeable and is significantly affected by pollution episodes. Boundary-layer NO2 exhibits irregular diurnal, weekly, intra-annual (within 15-100 day periods) and annual variations. Intra-annual variations of stratospheric and boundary-layer NO2 content with similar time scales can be coherent, but the time lag between these variations varies with time. © 2011 Taylor & Francis.

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