Download or read book Analysis and Investigation of the Effects of Atmospheric Gravity Waves on Infrared Emissions written by T. F. Tuan and published by . This book was released on 1983 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of atmospheric gravity waves on the spatial and temporal variability of infrared radiance (IR), have been investigated, beginning with an analysis of the effects of such waves on the number densities of various minor species which produce the more important infrared radiance. the results show the following features. (1) The spatial structures produced by gravity waves depend strongly on the excitation mechanism for the minor species. If the excitation is local such as for the 0H emissions, the structures in IR are sharply pronounced. If the excitation in integrated over extended sources, the structures are less sharply pronounced. (2) The temporal variance is far less influenced by the nature of the excitation. (3) The spatial structures increase with height. (4) Gravity waves with short vertical wave length compared to background structures produced both spatial and temporal variance in IR. (5) Gravity waves with long vertical wave length compared to background structures produce only temporal variance in IR. (6) Large amplitude gravity waves can produce instability and secondary IR structures with far more rapid temporal variance as well as more pronounced spatial variance. A dispersion relation for an inhomogeneous atmosphere has beend enveloped for analyzing gravity waves and can be used even when there is heavy wave reflection. The relation reduces to the well-known Hines' dispersion relation in a homogeneous isothermal atmosphere. (Author).
Download or read book Theoretical Investigation of the Effects of Atmospheric Gravity Waves on the Hydroxyl Emissions of the Atmosphere written by Tai-Fu Tuan and published by . This book was released on 1979 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of gravity waves on OH emission is investigated using a gravity-wave model valid for an inhomogeneous atmosphere and computed as well as semi-empirical data for the 'undisturbed' ozone and hydrogen profiles. The results show that (1) the magnitude of the response depends on the relative magnitudes and signatures of the vertical and horizontal wave-induced diffusion. Since in some regions the horizontal velocity field of the gravity wave can increase much more rapidly with height than the vertical field, horizontal diffusion even when there is a relatively sharp layer gradient; and (2) The structures in the OH profile produced by the gravity wave are in general but not always more pronounced below the intensity peak than above. The observed dark areas in OH emission can be produced by gravity waves with vertical wave length small compared with the half width of the intensity profile. (Author).
Download or read book An Investigation of Atmospheric Dynamics Through Their Effects on Mesospheric Optical Emission written by Tai-Fu Tuan and published by . This book was released on 1987 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research is described on various aspects of the dynamics of atmospheric gravity waves and their effect on mesospheric airglow emissions, in particular hydroxyl emission. Simultaneous observations of mesospheric optical emissions obtained during the MAPSTAR campaign are analyzed using maximum energy spectral analysis and other methods. The velocity field profiles extracted from this data are compared with gravity wave models based on a realistic nonisothermal background atmosphere. This work enables one to make direct comparisons between airflow data and radar determined wind profiles. A program aimed at investigating small temporal and spatial scale airflow fluctuations is outlined, and the simultaneous ducting and filtering of short period gravity waves by an atmosphere with a nonisothermal temperature profile is modeled theoretically. It is shown that waves from lower-atmospheric or terrestrial sources with group velocity upward are reflected at the altitude where the wave frequency becomes equal to the local Brunt Vaisala frequency. This filters out the shorter period waves, preventing them from reaching higher altitudes and, in conjunction with the ground boundary condition, results in a set of fully guided modes, whose frequency dispersion is investigated.
Download or read book Middle Atmosphere written by PLUMB and published by Birkhäuser. This book was released on 2013-11-21 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Studies of Non LTE Atmospheric Emissions Modeling and Data Analysis written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents research that has been carried out for the purpose of furthering the understanding of infrared emissions in the non-LTE regions of the Earth's atmosphere. Our effort has consisted of developing and exercising computer models of the quiescent and aurorally disturbed atmosphere, analyzing data from rocket and satellite experiments to validate and extend the models, and drawing upon our experience to help plan for the MSX mission. Specifically, we have used our models to simulate data from the SISSI and MAP/WINE campaigns and the CIRRIS mission, perform benchmark calculations to validate radiative transfer algorithms, and study the effects of gravity waves on non-LTE populations and atmospheric cooling in the mesopause region. We have performed spectral analysis on CIRRIS data, and used the models to identify processes contributing to the 4.3 um emissions seen in the data. We present a detailed description of how to use Atmospheric Radiance Code (ARC), the non-LTE code that we employ for these purposes. We also summarize our role in MSX experiment planning, and software development for automated analysis of MSX Spectrographic Imager data.
Download or read book Gravity wave emission from jet systems in the differentially heated rotating annulus experiment written by Costanza Rodda and published by Cuvillier Verlag. This book was released on 2019-11-22 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal gravity waves are fully recognised for the relevant role they play in the atmos-pheric and oceanic dynamics of our planet. Over the past decades, several studies have successfully investigated generation, propagation, and dissipation of gravity waves. Although several phenomena are nowadays reasonably well explained, others still remain unclear and, therefore, an active research topic. One of the least understood aspects is the emission of gravity waves from jet and front systems in the atmosphere. This work proposes an experimental laboratory investigation of gravity waves generated from baroclinic jets and fronts using a differentially heated rotating annulus. Gravity waves are observed along the baroclinic jet and their properties, together with the con-ditions for their emission and propagation, are examined in detail. Finally, the energy partition among large- and small-scale wave phenomena is investigated. The resem-blance of the energy spectra obtained from the experimental data with the ones meas-ured in the atmosphere is noteworthy, therefore proving that this experimental configu-ration is well suited for the investigation of multi-scale dynamics.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric Infrared Radiance Variability written by C. H. Humphrey and published by . This book was released on 1981 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data concerning the spatial and temporal inhomogenities of atmospheric density and composition and their implication concerning the atmospheric infrared radiance are reviewed. Preliminary estimates of the variability in the radiance are presented. In addition, the range of scale sizes from small-scale variations is also considered.
Download or read book An Introduction to Atmospheric Gravity Waves written by Carmen J. Nappo and published by Elsevier. This book was released on 2002-09-12 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravity waves exist in all types of geophysical fluids, such as lakes, oceans, and atmospheres. They play an important role in redistributing energy at disturbances, such as mountains or seamounts and they are routinely studied in meteorology and oceanography, particularly simulation models, atmospheric weather models, turbulence, air pollution, and climate research. An Introduction to Atmospheric Gravity Waves provides readers with a working background of the fundamental physics and mathematics of gravity waves, and introduces a wide variety of applications and numerous recent advances. Nappo provides a concise volume on gravity waves with a lucid discussion of current observational techniques and instrumentation. Foreword is written by Prof. George Chimonas, a renowned expert on the interactions of gravity waves with turbulence. CD containing real data, computer codes for data analysis and linear gravity wave models included with the text
Download or read book Data Assimilation written by William Lahoz and published by Springer Science & Business Media. This book was released on 2010-07-23 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data assimilation methods were largely developed for operational weather forecasting, but in recent years have been applied to an increasing range of earth science disciplines. This book will set out the theoretical basis of data assimilation with contributions by top international experts in the field. Various aspects of data assimilation are discussed including: theory; observations; models; numerical weather prediction; evaluation of observations and models; assessment of future satellite missions; application to components of the Earth System. References are made to recent developments in data assimilation theory (e.g. Ensemble Kalman filter), and to novel applications of the data assimilation method (e.g. ionosphere, Mars data assimilation).
Download or read book Air Force Research Resum s written by and published by . This book was released on with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronomy of the Earth s Atmosphere and Ionosphere written by Mangalathayil Ali Abdu and published by Springer Science & Business Media. This book was released on 2011-02-26 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a multi-author treatise on the most outstanding research problems in the field of the aeronomy of the Earth’s atmosphere and ionosphere, encompassing the science covered by Division II of the International Association of Geomagnetism and Aeronomy (IAGA). It contains several review articles and detailed papers by leading scientists in the field. The book is organized in five parts: 1) Mesosphere-Lower Thermosphere Dynamics and Chemistry; 2) Vertical Coupling by Upward Propagating Waves; 3) Ionospheric Electrodynamics and Structuring; 4) Thermosphere- Ionosphere Coupling, Dynamics and Trends and 5) Ionosphere-Thermosphere Disturbances and Modeling. The book consolidates the progress achieved in the field in recent years and it serves as a useful reference for graduate students as well as experienced researchers.
Download or read book The Upper Atmosphere written by Walter Dieminger and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1023 pages. Available in PDF, EPUB and Kindle. Book excerpt: Especially due to the increasing environmental problems there is a need to collect as many data as possible in the upper atmosphere. This book serves as a general multidisciplinary guide and introduction for a more effective use of the large amount of now available data from the Earth's atmosphere. It also shows the problems of the use of large amounts of time series data - for basic science as well as for environmental monitoring - and the related information systems. The book is aimed for scientists and students interested in the Earth's atmosphere which is vital for the understanding of environmental changes in the global system Earth.
Download or read book Effects of Atmospheric Aerosols on Infrared Irradiance at the Earth s Surface in a Nonurban Environment written by M. R. Riches and published by . This book was released on 1975 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summaries of Projects Completed written by National Science Foundation (U.S.) and published by . This book was released on with total page 1108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Interaction Between Gravity Waves and Atmospheric Thermal Tides written by Ryan Matthew Agner and published by . This book was released on 2017 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract Gravity waves and thermal tides are two of the most important dynamical features of the atmosphere. They are both generated in the lower atmosphere and propagate upward transporting energy and momentum to the upper atmosphere. This dissertation focuses on the interaction of these waves in the Mesosphere and Lower Thermosphere (MLT) region of the atmosphere using both observational data and Global Circulation Model (GCMs). The first part of this work focuses on observations of gravity wave interactions with the tides using both LIDAR data at the Star Fire Optical Range (SOR, 35°N, 106.5°W) and a meteor radar data at the Andes LIDAR Observatory (ALO, 30.3°s, 70.7°W). At SOR, the gravity waves are shown to enhance or damp the amplitude of the diurnal variations dependent on altitude while the phase is always delayed. The results compare well with previous mechanistic model results and with the Japanese Atmospheric General circulation model for Upper Atmosphere Research (JAGUAR) high resolution global circulation model. The meteor radar observed the GWs to almost always enhance the tidal amplitudes and either delay or advance the phase depending on the altitude. When compared to previous radar results from the same meteor radar when it was located in Maui, Hawaii, the Chile results are very similar while the LIDAR results show significant differences. This is because of several instrument biases when calculating GW momentum fluxes that is not significant when determining the winds. The radar needs to perform large amounts of all-sky averaging across many weeks, while the LIDAR directly detects waves in a small section of sky. The second part of this work focuses on gravity wave parameterization scheme effects on the tides in GCMs. The Specified Dynamics Whole Atmosphere Community Climate Model (SD-WACCM) and the extended Canadian Middle Atmosphere Model (used for this analysis. The gravity wave parameterization schemes in the scheme) have been shown to enhance the tidal amplitudes compared to observation is the parameterization scheme in SD-WACCM (Lindzen scheme) overdamps eCMAM) are eCMAM (Hines while the tides. It is shown here that the Hines scheme assumption that only small scale gravity waves force the atmosphere do not create enough drag to properly constrain the tidal amplitudes. The Lindzen scheme produces too much drag because all wave scales are assumed to be saturated thus continuing to provide forcing on the atmosphere above the breaking altitude. The final part of this work investigates GWs, tides and their interactions on a local time scale instead of a global scale in the two GCMs. The local time GW's in eCMAM are found to have a strong seasonal dependence, with the majority of the forcings at the winter pole at latitudes where the diurnal variations are weak limiting their interactions. In SD-WACCM, the largest local GW forcings are located at mid latitudes near where the diurnal variations peak causing them to dampen the diurnal amplitudes. On a local time level the diurnal variations may be a summation of many tidal modes. The analysis reveals that in eCMAM the DW1 tidal mode is by far the dominant mode accounting for the local time variations. The high amount of modulation of GWs by the DW1 tidal winds does not allow it to be properly constrained, causing it to dominate the local time diurnal variations. Similarly, the DW1 projection of GW forcing is dominant over all other modes and contributes the most to the local time diurnal GW variations. The local time wind variations in SD-WACCM are influenced by several tidal modes because the DW1 tide is of compatible amplitudes to other modes. This is because of the increased damping on the tide by the GWs. It is also found that the local GW diurnal variations have significant contributions from all tidal modes due to the time and location of the forcing being dependent only on the tropospheric source regions and not the at altitude tidal winds.
Download or read book Radiation Transport Effects and the Interpretation of Infrared Images of Gravity Waves and Turbulence written by and published by . This book was released on 1998 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiation transport modulates the spatial frequencies of atmospheric structures, acting as a low pass filter, which causes the power spectra of the accumulated radiance to have different power spectral slopes than the underlying atmospheric structure. Additional effects arise because of the non-stationarity of the atmosphere. The SHARC atmospheric radiance code is used to model both equilibrium and non-equilibrium radiance and radiance fluctuation statistics. It predicts two dimensional radiance spatial covariance functions and power spectral densities, PSDs. Radiance power spectral slopes for paths through isotropic Kolmogorov turbulence are predicted to vary from 5/3 to 8/3 depending on the length of the path through the turbulence. The input gravity wave 3-D covariances and PSDs of atmospheric temperature are consistent with current gravity wave theory, having vertical and horizontal power spectral indices of -3 and 5/3, respectively. Altitude profiles of variances and correlation lengths account for the non-stationary of the gravity wave structure in the atmosphere. The radiance covariance and PSD power spectral slopes differ from the atmospheric gravity wave temperature model values of -3 and 5/3. These modulations depend on LOS orientations, and scale lengths of the sampled altitudes along the LOS.
