Author: Cameron Homeyer
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Stratosphere-troposphere exchange processes are responsible for controlling the distribution of chemically and radiatively important trace gases in the upper troposphere and lower stratosphere. Extensive characterization of exchange processes is critical to the development of our understanding and prediction of the climate system. This study examines the occurrence and dynamical and chemical characteristics related to two primary stratosphere-troposphere exchange processes: Rossby wavebreaking and moist convection. Intrusions of air from the tropical upper troposphere into the extratropical stratosphere above the subtropical jet via Rossby wavebreaking potentially have a significant impact on the composition of the lowermost stratosphere (the stratospheric part of the "middleworld"). We first present an analysis of tropospheric intrusion events observed in aircraft observations using kinematic and chemical diagnostics. The transport processes operating during each event are discussed using high-resolution model analyses and backward trajectory calculations. In situ chemical observations of the tropospheric intrusions are used to estimate the mixing timescales of the observed intrusions through use of a simple box model and trace species with different photo-chemical lifetimes. We estimate that the timescale for an intrusion to mix with the background stratospheric air is 5 to 6 days. Detailed analysis of small-scale features with tropospheric characteristics observed in the stratosphere suggests frequent irreversible transport associated with tropospheric intrusions. We also present a 30-year climatology (1981-2010) of anticyclonically and cyclonically sheared Rossby wave-breaking events along the boundary of the tropics in the 350-500 K potential temperature range from ECMWF ERA-Interim reanalyses. Lagrangian transport analyses show poleward transport at altitudes below and above the 370-390 K layer. Poleward transport at lower levels is in disagreement with previous studies and is shown to be largely dependent on the choice of tropical boundary. In addition, transport analyses reveal three modes of transport for anticyclonic wavebreaking events near the tropical tropopause (380 K): poleward, equatorward, and bidirectional. These transport modes are associated with distinct characteristics in the geometry of the mean flow. Stratospheric intrusions (tropopause folds) are known to be major contributors to stratosphere-troposphere exchange. The specific mixing processes that lead to irreversible exchange between stratospheric intrusions and the surrounding troposphere, however, are not entirely understood. This study presents direct observations of moist convection penetrating into stratospheric intrusions. The characteristics of convective injection are shown by using in situ aircraft measurements, radar reflectivities, and model analyses. Convective injection is observed at altitudes up to 5 km above the bottom of a stratospheric intrusion. Aircraft measurements show that convective injection in stratospheric intrusions can be uniquely identified by coincident observations of water vapor greater than about 100 ppmv and ozone greater than about 125 ppbv. Trajectory analyses show that convective injection can impact transport in both directions: from troposphere to stratosphere and from stratosphere to troposphere. We present a conceptual model of the synoptic meteorological conditions conducive to convective injection in stratospheric intrusions. In particular, convective injection is found to be associated with a "split front" where the upper-level frontal boundary outruns the surface cold front.
Author: K. Mohanakumar
Publisher: Springer Science & Business Media
ISBN: 1402082177
Category : Science
Languages : en
Pages : 424
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Book Description
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.
Author: Huang Yang
Publisher:
ISBN:
Category :
Languages : en
Pages : 158
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Book Description
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.
Author: Rachid Moustabchir
Publisher:
ISBN:
Category : Stratospheric circulation
Languages : en
Pages :
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Book Description
Author: L. M. Polvani
Publisher: John Wiley & Sons
ISBN: 1118671597
Category : Science
Languages : en
Pages : 514
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Book Description
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.
Author: Stanley Q. Kidder
Publisher: Elsevier
ISBN: 0080572006
Category : Science
Languages : en
Pages : 481
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Book Description
At last, a book that has what every atmospheric science and meteorology student should know about satellite meteorology: the orbits of satellites, the instruments they carry, the radiation they detect, and, most importantly, the fundamental atmospheric data that can be retrieved from their observations.Key Features* Of special interest are sections on:* Remote sensing of atmospheric temperature, trace gases, winds, cloud and aerosol data, precipitation, and radiation budget* Satellite image interpretation* Satellite orbits and navigation* Radiative transfer fundamentals
Author: Daniel J. Jacob
Publisher: Princeton University Press
ISBN: 0691001855
Category : Nature
Languages : en
Pages : 280
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Book Description
Atmospheric chemistry is one of the fastest growing fields in the earth sciences. Until now, however, there has been no book designed to help students capture the essence of the subject in a brief course of study. Daniel Jacob, a leading researcher and teacher in the field, addresses that problem by presenting the first textbook on atmospheric chemistry for a one-semester course. Based on the approach he developed in his class at Harvard, Jacob introduces students in clear and concise chapters to the fundamentals as well as the latest ideas and findings in the field. Jacob's aim is to show students how to use basic principles of physics and chemistry to describe a complex system such as the atmosphere. He also seeks to give students an overview of the current state of research and the work that led to this point. Jacob begins with atmospheric structure, design of simple models, atmospheric transport, and the continuity equation, and continues with geochemical cycles, the greenhouse effect, aerosols, stratospheric ozone, the oxidizing power of the atmosphere, smog, and acid rain. Each chapter concludes with a problem set based on recent scientific literature. This is a novel approach to problem-set writing, and one that successfully introduces students to the prevailing issues. This is a major contribution to a growing area of study and will be welcomed enthusiastically by students and teachers alike.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309174325
Category : Science
Languages : en
Pages : 621
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Book Description
How can we understand and rise to the environmental challenges of global change? One clear answer is to understand the science of global change, not solely in terms of the processes that control changes in climate and the composition of the atmosphere, but in how ecosystems and human society interact with these changes. In the last two decades of the twentieth century, a number of such research effortsâ€"supported by computer and satellite technologyâ€"have been launched. Yet many opportunities for integration remain unexploited, and many fundamental questions remain about the earth's capacity to support a growing human population. This volume encourages a renewed commitment to understanding global change and sets a direction for research in the decade ahead. Through case studies the book explores what can be learned from the lessons of the past 20 years and what are the outstanding scientific questions. Highlights include: Research imperatives and strategies for investigators in the areas of atmospheric chemistry, climate, ecosystem studies, and human dimensions of global change. The context of climate change, including lessons to be gleaned from paleoclimatology. Human responses toâ€"and forcing ofâ€"projected global change. This book offers a comprehensive overview of global change research to date and provides a framework for answering urgent questions.
Author: Rolf Müller (physicien.)
Publisher: Royal Society of Chemistry
ISBN: 1849730024
Category : Science
Languages : en
Pages : 347
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Book Description
In recent years, several new concepts have emerged in the field of stratospheric ozone depletion, creating a need for a concise in-depth publication covering the ozone-climate issue. This monograph fills that void in the literature and gives detailed treatment of recent advances in the field of stratospheric ozone depletion. It puts particular emphasis on the coupling between changes in the ozone layer and atmospheric change caused by a changing climate. The book, written by leading experts in the field, brings the reader the most recent research in this area and fills the gap between advanced textbooks and assessments.
Author: John Marshall
Publisher: Academic Press
ISBN: 0080954561
Category : Science
Languages : en
Pages : 345
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Book Description
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 andbeginning graduate students* Provides a useful educational tool through a combination of observations andlaboratory demonstrations which can be viewed over the web* Contains instructions on how to reproduce the simple but informativelaboratory experiments* Includes copious problems (with sample answers) to help students learn thematerial.
