Stratosphere Troposphere Interaction During Stratospheric Sudden Warming Events
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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.
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.
Middle Atmosphere
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Author : PLUMB
language : en
Publisher: Birkhäuser
Release Date : 2013-11-21
Middle Atmosphere written by PLUMB and has been published by Birkhäuser this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-11-21 with Science categories.
PAGEOPH, stratosphere, these differences provide us with new evidence, interpretation of which can materially help to advance our understanding of stratospheric dynamics in general. It is now weil established that smaller-scale motions-in particular gravity waves and turbulence-are of fundamental importance in the general circulation of the mesosphere; they seem to be similarly, if less spectacularly, significant in the troposphere, and probably also in the stratosphere. Our understanding of these motions, their effects on the mean circulation and their mutual interactions is progressing rapidly, as is weil illustrated by the papers in this issue; there are reports of observational studies, especially with new instruments such as the Japanese MV radar, reviews of the state of theory, a laboratory study and an analysis of gravity waves and their effects in the high resolution "SKYHI" general circulation model. There are good reasons to suspect that gravity waves may be of crucial significance in making the stratospheric circulation the way it is (modeling experience being one suggestive piece of evidence for this). Direct observational proof has thus far been prevented by the difficulty of making observations of such scales of motion in this region; in one study reported here, falling sphere observations are used to obtain information on the structure and intensity of waves in the upper stratosphere.
Middle Atmosphere Dynamics
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Author : David G. Andrews
language : en
Publisher: Academic Press
Release Date : 2016-07-21
Middle Atmosphere Dynamics written by David G. Andrews and has been published by Academic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-07-21 with Science categories.
For advanced undergraduate and beginning graduate students in atmospheric, oceanic, and climate science, Atmosphere, Ocean and Climate Dynamics is an introductory textbook on the circulations of the atmosphere and ocean and their interaction, with an emphasis on global scales. It will give students a good grasp of what the atmosphere and oceans look like on the large-scale and why they look that way. The role of the oceans in climate and paleoclimate is also discussed. The combination of observations, theory and accompanying illustrative laboratory experiments sets this text apart by making it accessible to students with no prior training in meteorology or oceanography. * Written at a mathematical level that is appealing for undergraduates and beginning graduate students * Provides a useful educational tool through a combination of observations and laboratory demonstrations which can be viewed over the web * Contains instructions on how to reproduce the simple but informative laboratory experiments * Includes copious problems (with sample answers) to help students learn the material.
Sub Seasonal To Seasonal Prediction
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Author : Andrew Robertson
language : en
Publisher: Elsevier
Release Date : 2018-10-19
Sub Seasonal To Seasonal Prediction written by Andrew Robertson and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-10-19 with Science categories.
The Gap Between Weather and Climate Forecasting: Sub-seasonal to Seasonal Prediction is an ideal reference for researchers and practitioners across the range of disciplines involved in the science, modeling, forecasting and application of this new frontier in sub-seasonal to seasonal (S2S) prediction. It provides an accessible, yet rigorous, introduction to the scientific principles and sources of predictability through the unique challenges of numerical simulation and forecasting with state-of-science modeling codes and supercomputers. Additional coverage includes the prospects for developing applications to trigger early action decisions to lessen weather catastrophes, minimize costly damage, and optimize operator decisions. The book consists of a set of contributed chapters solicited from experts and leaders in the fields of S2S predictability science, numerical modeling, operational forecasting, and developing application sectors. The introduction and conclusion, written by the co-editors, provides historical perspective, unique synthesis and prospects, and emerging opportunities in this exciting, complex and interdisciplinary field. Contains contributed chapters from leaders and experts in sub-seasonal to seasonal science, forecasting and applications Provides a one-stop shop for graduate students, academic and applied researchers, and practitioners in an emerging and interdisciplinary field Offers a synthesis of the state of S2S science through the use of concrete examples, enabling potential users of S2S forecasts to quickly grasp the potential for application in their own decision-making Includes a broad set of topics, illustrated with graphic examples, that highlight interdisciplinary linkages
Investigating The Link Between Tropospheric Blocking And Sudden Stratospheric Warming In The Northern Hemisphere
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Author : Michael Ewens Kelleher
language : en
Publisher:
Release Date : 2014
Investigating The Link Between Tropospheric Blocking And Sudden Stratospheric Warming In The Northern Hemisphere written by Michael Ewens Kelleher and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
The link between sudden stratospheric warmings (SSWs) and tropospheric blocking events has been heavily investigated, both in the composite sense, as well as individual case studies. The implications of improved SSW forecasting include improved surface weather predictability, as the warmings have long time scale impacts on the troposphere. In this study, the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis (Kalnay et al., 1996), and NASA's Modern Era Retrospective Reanalysis (MERRA) (Rienecker et al., 2011) data sets were used to differentiate blocking events that occur without the presence of any stratospheric warming from those that are linked with warmings, either preceding or following it. This was accomplished through the generation of composites of geopotential height fields, Ertel's potential vorticity on the longitude-time plane and averaged over the polar cap, zonal mean zonal wind diagnosis, and meridional eddy heat flux. It was found that indeed there are several distinguishing features that discriminate blocking events associated with SSWs from those that are not. Firstly, the zonal mean zonal wind appears to link the stratosphere with the troposphere during blocking events associated with SSWs, while no such link appears in the events that are not. The meridional eddy heat flux features large ten-day averaged values in the period before and just after block onset in the SSW associated composites, while it is absent in the non-associated composites. The polar cap PV average also separates the SSW associated events from the non-events, with an anticyclonic anomaly before block onset, and cyclonic anomaly after onset, whereas the non-events feature only a minimal change in tropospheric PV. The tropospheric polar cap PV and meridional eddy heat flux were used as forecast indicators for historical SSW events in both data sets, and presented nominal skill over climatology. A statistical comparison was also performed on the duration of blocking, that indicates that longer duration blocks are more likely associated with SSW events, but this was only statistically significant in the NCEP/NCAR Reanalysis, and was not replicated with the MERRA data set.
Downward Influence Of Stratospheric Final Warming Events In An Idealized Model
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Author : Lantao Sun
language : en
Publisher:
Release Date : 2010
Downward Influence Of Stratospheric Final Warming Events In An Idealized Model written by Lantao Sun and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
The stratospheric Ơ̐1nal warming is the Ơ̐1nal transition of the zonal winds from wintertime westerlies to summertime easterlies as the solar heating of the high latitude stratosphere increases in the springtime. Recent observational analyses suggested that stratospheric final warming makes a signiƠ̐1cant contribution to the spring transitions in the lower troposphere, especially in the Northern Hemisphere. It is still not clear, however, whether these transitions are due to the downward inƠ̐2uence from the stratosphere. We Ơ̐1rst explore the hypothesis that much of the observed tropospheric signal of the Ơ̐1nal warming is initiated from the stratosphere. Large ensembles of Ơ̐1nal warmings are simulated in an idealized dynamical core model, by imposing a radiative equilibrium temperature transition from winter to summer only in the stratosphere. Our results suggest that a substantial fraction of the observed tropospheric changes that occur in conjunct with the Ơ̐1nal warming are induced from the stratosphere. We further investigate the mechanisms of the downward inƠ̐2uence of the Ơ̐1nal warmings on the tropospheric circulation. Results from our zonally symmetric model suggest that stratospheric wave driving can induce a residual circulation and aƠ̐0ect the tropospheric circulation. The tropospheric signals due to this mechanism are, however, very weak and are mostly conƠ̐1ned to the upper troposphere. On the other hand, the stratosphere can aƠ̐0ect the propagation of planetary waves from the troposphere, resulting in a burst of wave activity and the zonal wind deceleration prior to the Ơ̐1nal warming in the troposphere. We also perform a series of perturbation experiments for the sudden and Ơ̐1nal warmings to test the roles of the troposphere and the stratosphere in determining the predictability of stratospheric warmings. For a late Ơ̐1nal warming, almost all of the predictability comes from the troposphere. For the rest of the Ơ̐1nal warmings and for sudden warmings, however, the troposphere determines the predictability until very close to the time of warming onset. This Ơ̐1nding, consistent with the conventional view of the warming, reƠ̐2ects that center role of the troposphere in determining the stratospheric warmings. Results from a comprehensive global climate model, the Whole-Atmosphere Community Climate Model (WACCM), are used to analyze the Ơ̐1nal warmings in both hemispheres. Although WACCM has zonal winds that are too strong in the spring, which causes the mean onset dates to be delayed at least one month with respect to the observations, the zonal wind evolutions resemble the observations. The similarity between the models and observations suggests that the downward inƠ̐2uence of the stratospheric Ơ̐1nal warming on the tropospheric circulation is real and substantial, especially in the Northern Hemisphere.
Stratospheric Circulation Study Role Of The Subtropical Jet Stream In Troposphere Stratosphere Teleconnections
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Author : Walter A. Bohan
language : en
Publisher:
Release Date : 1971
Stratospheric Circulation Study Role Of The Subtropical Jet Stream In Troposphere Stratosphere Teleconnections written by Walter A. Bohan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1971 with categories.
During the late winter months when the subtropical jet stream reaches its maximum intensity, confluence patterns develop between the subtropical and polar-front jet streams. Through the increased vertical velocities and vorticity production, teleconnections between the tropospheric Ferrel westerlies and the stratospheric polar-night westerlies becomes possible. This can cause a disruption of the circular pattern of the polar-night vortex and result in the development of large-amplitude wave trains which precede the occurrence of sudden stratospheric warming events. (Author).
The Stratosphere
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Author : L. M. Polvani
language : en
Publisher: John Wiley & Sons
Release Date : 2013-04-30
The Stratosphere written by L. M. Polvani and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-04-30 with Science categories.
Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 190. The Stratosphere: Dynamics, Transport, and Chemistry is the first volume in 20 years that offers a comprehensive review of the Earth's stratosphere, increasingly recognized as an important component of the climate system. The volume addresses key advances in our understanding of the stratospheric circulation and transport and summarizes the last two decades of research to provide a concise yet comprehensive overview of the state of the field. This monograph reviews many important aspects of the dynamics, transport, and chemistry of the stratosphere by some of the world's leading experts, including up-to-date discussions of Dynamics of stratospheric polar vortices Chemistry and dynamics of the ozone hole Role of solar variability in the stratosphere Effect of gravity waves in the stratosphere Importance of atmospheric annular modes This volume will be of interest to graduate students and scientists who wish to learn more about the stratosphere. It will also be useful to atmospheric science departments as a textbook for classes on the stratosphere.
Long Term Investigation Of The Lunar Tide In The Equatorial Electrojet During Stratospheric Sudden Warmings
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Author : Tarique Adnan Siddiqui
language : en
Publisher:
Release Date : 2017
Long Term Investigation Of The Lunar Tide In The Equatorial Electrojet During Stratospheric Sudden Warmings written by Tarique Adnan Siddiqui and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
The ionosphere, which is strongly influenced by the Sun, is known to be also affected by meteorological processes. These processes, despite having their origin in the troposphere and stratosphere, interact with the upper atmosphere. Such an interaction between atmospheric layers is known as vertical coupling. During geomagnetically quiet times, when near-Earth space is not under the influence of solar storms, these processes become important drivers for ionospheric variability. Studying the link between these processes in the lower atmosphere and the ionospheric variability is important for our understanding of fundamental mechanisms in ionospheric and meteorological research. A prominent example of vertical coupling between the stratosphere and the ionosphere are the so-called stratospheric sudden warming (SSW) events that occur usually during northern winters and result in an increase in the polar stratospheric temperature and a reversal of the circumpolar winds. While the phenomenon of SSW is confined to the northern polar...