921 research outputs found
Chemistry-climate model SOCOL: a validation of the present-day climatology
In this paper we document 'SOCOL', a new chemistry-climate model, which has been ported for regular PCs and shows good wall-clock performance. An extensive validation of the model results against present-day climate data obtained from observations and assimilation data sets shows that the model describes the climatological state of the atmosphere for the late 1990s with reasonable accuracy. The model has a significant temperature bias only in the upper stratosphere and near the tropopause at high latitudes. The latter is the result of the rather low vertical resolution of the model near the tropopause. The former can be attributed to a crude representation of radiation heating in the middle atmosphere. A comparison of the simulated and observed link between the tropical stratospheric structure and the strength of the polar vortex shows that in general, both observations and simulations reveal a higher temperature and ozone mixing ratio in the lower tropical stratosphere for the case with stronger Polar night jet (PNJ) and slower Brewer-Dobson circulation as predicted by theoretical studies
Scattering theory with finite-gap backgrounds: Transformation operators and characteristic properties of scattering data
We develop direct and inverse scattering theory for Jacobi operators (doubly
infinite second order difference operators) with steplike coefficients which
are asymptotically close to different finite-gap quasi-periodic coefficients on
different sides. We give necessary and sufficient conditions for the scattering
data in the case of perturbations with finite second (or higher) moment.Comment: 23 page
Low-energy expansion formula for one-dimensional Fokker-Planck and Schr\"odinger equations with periodic potentials
We study the low-energy behavior of the Green function for one-dimensional
Fokker-Planck and Schr\"odinger equations with periodic potentials. We derive a
formula for the power series expansion of reflection coefficients in terms of
the wave number, and apply it to the low-energy expansion of the Green
function
Influence of the Precipitating Energetic Particles on Atmospheric Chemistry and Climate
We evaluate the influence of the galactic cosmic rays (GCR), solar proton events (SPE), and energetic electron precipitation (EEP) on chemical composition of the atmosphere, dynamics, and climate using the chemistry-climate model SOCOL. We have carried out two 46-year long runs. The reference run is driven by a widely employed forcing set and, for the experiment run, we have included additional sources of NO x and HO x caused by all considered energetic particles. The results show that the effects of the GCR, SPE, and EEP fluxes on the chemical composition are most pronounced in the polar mesosphere and upper stratosphere; however, they are also detectable and statistically significant in the lower atmosphere consisting of an ozone increase up to 3% in the troposphere and ozone depletion up to 8% in the middle stratosphere. The thermal effect of the ozone depletion in the stratosphere propagates down, leading to a warming by up to 1K averaged over 46years over Europe during the winter season. Our results suggest that the energetic particles are able to affect atmospheric chemical composition, dynamics, and climat
Exact quantum master equation for a molecular aggregate coupled to a harmonic bath
We consider a molecular aggregate consisting of identical monomers. Each
monomer comprises two electronic levels and a single harmonic mode. The
monomers interact with each other via dipole-dipole forces. The monomer
vibrational modes are bilinearly coupled to a bath of harmonic oscillators.
This is a prototypical model for the description of coherent exciton transport,
from quantum dots to photosynthetic antennae. We derive an exact quantum master
equation for such systems. Computationally, the master equation may be useful
for the testing of various approximations employed in theories of quantum
transport. Physically, it offers a plausible explanation of the origins of
long-lived coherent optical responses of molecular aggregates in dissipative
environments
Indirect reporting. The role of the sentence structure in indirect reporting by L2 speakers
Currently research into indirect reporting in bilingual speech production is considered important because: a) indirect reporting involves work of cognitive, pragmatic and linguistic mechanisms in L2 speaker, thus reveals different mechanisms of language acquisition; b) indirect reporting is considered to be one of the most challenging tasks for L2 speakers; c) understanding of these obstacles could enable L2 teachers to foster language proficiency skills in L2 learners more effectively. There is a growing body of literature that looks into the relationship between the original utterance and the report, logical and inferential structure of indirect reports, the role of semantic and pragmatic factors in shaping indirect reports. Most of the studies have been based on examples and data in the English language, where subjects of research were bilinguals with the English language as L2 and various mother tongues L1. The central thesis of this paper is that L2 learners tend to overcomplicate the structure of a sentence in indirect reporting. This study therefore set out to assess the structure of indirect reports by bilingual speakers and determine possible reasons for overcomplicating of sentence structure. In addition, this study provides an opportunity to advance our knowledge of L2 acquisition
Chemistry-climate model SOCOL: a validation of the present-day climatology
International audienceIn this paper we document ''SOCOL'', a new chemistry-climate model, which has been ported for regular PCs and shows good wall-clock performance. An extensive validation of the model results against present-day climate obtained from observations and assimilation data sets shows that the model describes the climatological state of the atmosphere for the late 1990s with reasonable accuracy. The model has a significant temperature bias only in the upper stratosphere and near the tropopause in the tropics and high latitudes. The latter is the result of the rather low vertical resolution of the model near the tropopause. The former can be attributed to a crude representation of the radiation heating in the middle atmosphere. A comparison of the simulated and observed link between the tropical stratospheric structure and the strength of the polar vortex shows that in general, both observations and simulations reveal a higher temperature and ozone mixing ratio in the lower tropical stratosphere for the case with stronger Polar night jet (PNJ) as predicted by theoretical studies
In memoriam of Alexander Golovin (1939–2013)
No abstract available
SPECIFICATION OF ACCOUNTING OF FIXED ASSETS UNDER INTERNATIONAL AND RUSSIAN STANDARDS
The problems of definition and recognition of fixed assets are considered. The current Accounting Regulation «Accounting for Fixed Assets» is compared with the International Standard «Fixed Assets» in terms of determining and recognizing objects in accounting and reporting
SPECIFICATION OF ACCOUNTING OF FIXED ASSETS UNDER INTERNATIONAL AND RUSSIAN STANDARDS
The problems of definition and recognition of fixed assets are considered. The current Accounting Regulation «Accounting for Fixed Assets» is compared with the International Standard «Fixed Assets» in terms of determining and recognizing objects in accounting and reporting
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