Stratosphere Troposphere Interactions
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Stratosphere Troposphere Interactions
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Author : K. Mohanakumar
language : en
Publisher: Springer Science & Business Media
Release Date : 2008-07-03
Stratosphere Troposphere Interactions written by K. Mohanakumar and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-07-03 with Science categories.
Stratospheric processes play a signi?cant role in regulating the weather and c- mate of the Earth system. Solar radiation, which is the primary source of energy for the tropospheric weather systems, is absorbed by ozone when it passes through the stratosphere, thereby modulating the solar-forcing energy reaching into the t- posphere. The concentrations of the radiatively sensitive greenhouse gases present in the lower atmosphere, such as water vapor, carbon dioxide, and ozone, control the radiation balance of the atmosphere by the two-way interaction between the stratosphere and troposphere. The stratosphere is the transition region which interacts with the weather s- tems in the lower atmosphere and the richly ionized upper atmosphere. Therefore, this part of the atmosphere provides a long list of challenging scienti?c problems of basic nature involving its thermal structure, energetics, composition, dynamics, chemistry, and modeling. The lower stratosphere is very much linked dynamically, radiatively,and chemically with the upper troposphere,even though the temperature characteristics of these regions are different. The stratosphere is a region of high stability, rich in ozone and poor in water - por and temperature increases with altitude. The lower stratospheric ozone absorbs the harmful ultraviolet (UV) radiation from the sun and protects life on the Earth. On the other hand, the troposphere has high concentrations of water vapor, is low in ozone, and temperature decreases with altitude. The convective activity is more in the troposphere than in the stratosphere.
Model Sensitivities And Stratosphere Troposphere Interactions
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Author : Alice Flint
language : en
Publisher:
Release Date : 2012
Model Sensitivities And Stratosphere Troposphere Interactions written by Alice Flint and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
In recent years it has been shown that the troposphere is affected by changes in the climate of the stratosphere as well as vice versa. Investigating the downward influence has implications for understanding not only past climate but also for predicting future climate. A simplified, Newtonian-forced general circulation model is used to investigate the impact of changes in the stratosphere on the tropospheric circulation. First the sensitivity of tropospheric climate, tropospheric climate variability and response to stratospheric forcing to the surface temperature relaxation timescale are investigated. Changes to this parameter are shown to have significant impact on the model's climatology, influencing both the thermal structure of the lower troposphere and the position of the eddy driven mid-latitude jet. The change in mean tropospheric climate influences the annular variability, including its timescale. A strong relationship between this timescale and the magnitude of response to forcing is found, which is consistent with the fluctuation - dissipation theorem. The tropospheric response for both the surface parameter experiments and stratospheric temperature forcings is shown to be remarkably similar. This indicates that the same dynamical feedbacks are triggered, and thus resulting in the same annular mode-like response. Further, the impact of an improved representation of the stratosphere (in a model of greater vertical extent) and its effect on the response to a range of stratospheric heating perturbations is investigated. The extent of the heating perturbations, both in latitude and altitude, are shown to have a significant impact on the tropospheric response. These experiments further reveal an influence of the tropospheric eddy response back onto the stratospheric forcing region which modifies the direct stratospheric response to the heating. This suggests a strong two way coupling between the lower stratosphere and the tropospheric jets and storm track eddies.
Stratosphere Troposphere Interaction During Stratospheric Sudden Warming Events
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Author : Daniela Iris Vera Domeisen
language : en
Publisher:
Release Date : 2012
Stratosphere Troposphere Interaction During Stratospheric Sudden Warming Events written by Daniela Iris Vera Domeisen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
The stratosphere and the troposphere exhibit a strong coupling during the winter months. However, the coupling mechanisms between the respective vertical layers are not fully understood. An idealized spectral core dynamical model is utilized in the present study in order to clarify the coupling timing, location and mechanisms. Since the coupling between the winter stratosphere and troposphere is strongly intensified during times of strong stratospheric variability such as stratospheric warmings, these events are simulated in the described model for the study of stratosphere - troposphere coupling, while for comparison the coupling is also assessed for weaker stratospheric variability. While the upward coupling by planetary-scale Rossby waves in the Northern Hemisphere is well understood, the Southern Hemisphere exhibits traveling wave patterns with a weaker impact on the stratospheric ow. However the tropospheric generation mechanism of these waves is not well understood and is investigated in this study. It is found that in the model atmosphere without a zonally asymmetric wave forcing, traveling waves are unable to induce a significant wave ux into the stratosphere. In the absence of synoptic eddy activity, however, the tropospheric ow is baroclinically unstable to planetary-scale waves, and the generated planetary waves are able to propagate into the stratosphere and induce sudden warmings comparable in frequency and strength to the Northern Hemisphere. While baroclinic instability of long waves may be further strengthened by the addition of moisture, the real atmosphere also exhibits strong synoptic eddy activity, and it will have to be further explored if the atmosphere exhibits periods where synoptic eddies are weak enough to allow for baroclinic instability of long waves. In order to further investigate the coupling between the stratosphere and the troposphere, cases of strong coupling are investigated in the analysis of a Northern Hemisphere - like winter atmosphere. A realistic frequency and strength of sudden warmings is obtained using a zonal wave-2 topographic forcing. An angular momentum budget analysis yields that the Eliassen-Palm (EP) flux is closely balanced by the residual circulation dominated by the Coriolis term on a daily basis, while the change in zonal wind is a small residual between these dominant terms. In the stratosphere, the EP flux term and the Coriolis term balance well in time but not exactly in magnitude, yielding a polar stratospheric weakening of the zonal mean wind as observed during stratospheric warmings. In the troposphere, the loss of angular momentum before a sudden warming induces a weak negative annular mode response, which is amplified by the downward propagating signal about three weeks after the sudden warming. The angular momentum budget does not reveal the mechanism of downward influence, but it nevertheless clarifies the momentum balance of the stratosphere - troposphere system, indicating that the effects of the waves and the residual circulation have to be considered at the same time. Since the annular mode response cannot be directly investigated using the angular momentum budget, the annular mode coupling between the stratosphere and the troposphere is further investigated using a statistical approach. The annular mode response is often framed in terms of Empirical Orthogonal Functions (EOFs), but it is here found that for the stratosphere - troposphere system with its strong vertical pressure gradient, EOFs are strongly dependent on the weighting of the data, while Principal Oscillation Patterns (POPs) are considerably less sensitive to an applied weighting while returning the dominant structures of variability. This encourages further research and application of POP modes for the use of stratosphere - troposphere coupling. These findings represent an improvement of the understanding of stratosphere - troposphere coupling and the results are another step in the direction of finding the mechanism of stratosphere - troposphere coupling and the downward influence after the occurrence of a stratospheric sudden warming, which may influence long-term weather prediction in the troposphere.
Eurasian Snow Cover And The Role Of Linear Interference In Stratosphere Troposphere Interactions
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Author : Karen L. Smith
language : en
Publisher:
Release Date : 2012
Eurasian Snow Cover And The Role Of Linear Interference In Stratosphere Troposphere Interactions written by Karen L. Smith and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Physics Theses categories.
Dynamic Coupling And Chemical Transport Between The Stratosphere And The Troposphere
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Author : Huang Yang
language : en
Publisher:
Release Date : 2015
Dynamic Coupling And Chemical Transport Between The Stratosphere And The Troposphere written by Huang Yang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
Although the stratosphere and troposphere are separately different in many aspects (thermal structure, dynamic circulation, chemical composition and etc.), studies in recent decades have indicated a much stronger connection between these two distinct layers. Dynamically, the stratospheric circulation is driven by the eddies that are dominantly generated in the troposphere, whereas the troospheric circulation varies, in some ocassion, mostly due to the circulation and eddy perturbation originated in the stratosphere. The exchange and transport between the two layers, on the other hand, tend to alter the chemical compostion on both sides, and hence induce subsequent influences on the chemistry and radiation within the two layers. In this study, we further enrich the understanding on the connection between the stratosphere and troposphere by examining their dynamic coupling and chemical exchange. We first investigate the dynamic impact from the troposphere to the stratosphere by examining the role of tropical sea surface temperature (SST). By designing several idealized SST forcing simulations in an aqua-planet model, we find that the zonal distribution of SST perturbations has a major impact on the vertical and meridional structure of the BDC as compared with other SST characteristics. Zonally localized SST heatings tend to generate a shallow acceleration of the stratospheric residual circulation, whereas SST heatings with a zonally symmetric structure tend to produce a deep strengthening of the stratospheric residual circulation. The shallow versus deep strengthening of the stratospheric residual circulation change has been linked to wave propagation and dissipation in the subtropical lower stratosphere rather than wave generation in the troposphere. The dynamic impact from the stratosphere to the troposphere is then discussed by focusing on the downward influence of polar stratospheric ozone depletion. Three possible mechanisms are examined in an idealized dry model: the polar stratospheric cooling impacts tropospheric synoptic eddies via (a) the direct influences on the lower stratospheric synoptic eddies, (b) the planetary wave-induced residual circulation, and (c) the planetary eddy - synoptic eddy nonlinear interaction. It is argued that the planetary wave-induced residual circulation is not the dominant mechanism, and that the planetary eddies and further nonlinear interaction with synoptic eddies are more likely the key to the downward influence of the ozone depletion-like cooling. Last, the chemical interaction between the stratosphere and troposphere is explored by quantifying the stratosphere-troposphere exchange (STE) of ozone. The specified dynamics (SD) version of the Whole Atmosphere Community Climate Model (WACCM) is used to estimate the ozone STE along different isentropic surfaces (isentropic ozone STE herein). Net troposphere-to-stratosphere ozone STE is diagnosed in the subtropics (350 K - 380 K), while net stratosphereto-troposphere ozone STE is diagnosed in the extratropics (280 K - 350 K), with different magnitudes and seasonalities over different isentropic (meridional) regions. Potential vorticity (PV) sources induced by both differential diabatic heating and isentropic mixing contribute to the diagnosed isentropic ozone STE flux, but the latter is slightly larger. Moreover, results in the SD-WACCM are generally consistent with the analysis in a different model, the SD version of the Canadian Middle Atmosphere Model (CMAM), but the SD-CMAM diagnoses a smaller STE flux. This difference is associated with the different extent of isentropic mixing between the two models.
Dynamic Interactions Between The Troposphere And Stratosphere
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Author : James Paul Koermer
language : en
Publisher:
Release Date : 1980
Dynamic Interactions Between The Troposphere And Stratosphere written by James Paul Koermer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1980 with Stratosphere categories.
A primitive equation spectral model using spherical harmonics is formulated to study interactions between the troposphere and stratosphere in association with sudden stratospheric warmings. In order to follow vertical wave propagation so important to this process, the model consists of 31 levels with 5 in the troposphere and the other 26 in the stratosphere and mesosphere. Using sigma coordinates for the former and log-pressure coordinates for the latter, separate equations for each system are combined to form a single matrix governing equations. The gradual introduction of planetry scale topography to an initially balanced state representative of observed mean winter conditions in the Northern Hemisphere is used to force changes in the initial field during 40 day time integrations. Utilizing the same initial tropospheric conditions, three cases were run. The first case started with a weak polar night jet in the stratosphere and mesosphere. The second case had a much stronger polar vortex. For the third case, a lid was placed on the troposphere and no interaction was allowed with the atmosphere at higher levels. Results of these integrations indicate that realistic stratospheric warmings can be simulated by simple orographic forcing.
The Problem Of Troposphere And Stratosphere Interaction At Middle Latitudes
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Author : B. N. Trubnikov
language : en
Publisher:
Release Date : 1968
The Problem Of Troposphere And Stratosphere Interaction At Middle Latitudes written by B. N. Trubnikov and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1968 with categories.
A system of linearized equations is developed for the analysis of the interactions between the troposphere and the stratosphere. Ultimately, the meridional disturbance of the seasonal zonal state is described by a second-order differential equation with variable coefficients. Applied with modifications to the analysis of free atmospheric oscillations, it indicates that the existence of interrelated processes in the atmosphere and troposphere essentially depends not just on the scale of the process, but also on the mid-seasonal wind velocity and atmospheric stability. A coefficient of refraction from weather rocket data was calculated for mid-latitudes of the USSR, using the Rossby formula. Near the tropopause, this coefficient has a sharp discontinuity. A qualitative analysis of the coefficients distribution pattern enabled the modeling of the formation of barrier layers. It is conceivable that better understanding of the role of barrier layers will explain the formation of warmer regions at high altitudes and the 'explosive' nature of energy expansion upwards. The calculation involving a rough approximation of the refraction factor indicates that the strong meridional winds at mid-latitudes of the European USSR may be caused by the expansion of the meridional component from the troposphere into the stratosphere. (Author).
A Study Of Stratosphere Troposphere Coupling With An Aquaplanet Model
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Author : Jacob Ching Ho Cheung
language : en
Publisher:
Release Date : 2012
A Study Of Stratosphere Troposphere Coupling With An Aquaplanet Model written by Jacob Ching Ho Cheung and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
The coupling between stratosphere and troposphere (ST) has been studied extensively using simple circulation models. It is known that the ozone- rich stratosphere interact with the troposphere through both radiative and dynamical processes. However, many of the models used in these studies only assume a slab ocean with a fixed sea surface temperature (SST) profile. To investigate the role of the ocean in the stratosphere-troposphere coupling, a fully coupled atmosphere-ocean model, FORTE (Fast Ocean Rapid Troposphere Experiment) is used in this study. In this project the Earth is modelled as a perfect sphere with its surface covered with water. In the first set of our experiments we introduce a perturbation to the stratosphere by increasing ozone concentration by a factor of five. In the second experiment we repeat the ozone perturbation experiment with a fixed SST profile such that the atmosphere-ocean coupling is shut off. Our results demonstrate that by including a dynamical ocean, the strength of the jet streams is less sensitive to stratospheric ozone perturbations whereas the extent of their latitudinal displacements is greater. Both of these are found to be a consequence of SST anomalies induced by ocean dynamics. On the other hand, our results show that in the presence of an interactive ocean, there is a general increase in tropospheric air temperature except for polar regions, while lacking the banded anomaly pattern observed in our fixed SST experiment and other ST coupling studies.
Energy Interaction Between The Troposphere And Stratosphere
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Author : Lawrence S. Hanstrote
language : en
Publisher:
Release Date : 1960
Energy Interaction Between The Troposphere And Stratosphere written by Lawrence S. Hanstrote and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1960 with Advection (Meteorology) categories.
Tropospheric Ozone
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Author : Ivar S.A. Isaksen
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Tropospheric Ozone written by Ivar S.A. Isaksen and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
The main objective of the workshop was to increase our knowledge of ozone formation and distribution in the troposphere, its relation to precursor (NO~ and HC species) distribution, how it is affected by transport processes in the troposphere, and to show how the increasing levels of ozone can cause environmental problem. The focus was on the interaction of ozone on regional and global scales. There is mounting evidence that such interactions occur and that the ozone levels are increasing in most of the Northern Hemisphere tropo sphere. A likely source of ozone increase is human activity. As result of this, tropospheric climate may change significantly within a few decades, either through direct effects by ozone itself or indirectly through its effect on other radiatively active trace species. Further more, ozone may have adverse effects on vegetation over large continental areas due to enhanced levels which have been measured to take place. As it is well known that ozone plays a key role in the oxidation of a large number of chemical species in the troposphere, natural as well as man-made, the atmospheric distribution of important trace species like sulfur dioxide, nitrogen oxides and hydrocarbons could be markedly changed as a result of ozone changes. The rapidly increasing interest in tropospheric ozone, and the key role ozone plays in several atmospheric areas as well the obvious increase in the tropospheric concentration of ozone made ozone a natural choice as a topic for the workshop.