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 On the Interaction Between Thermal Tides and Gravity Waves in the Middle Atmosphere written by Fabian Senf and published by . This book was released on 2012 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Gravity Wave and Thermal Tide and Their Interactions in the Middle Atmosphere written by Xian Lu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravity waves (GWs) and tides are two strongest and most persistent waves in the middle atmosphere of the Earth. They are usually generated in the lower atmosphere and propagate upward to the middle and upper atmosphere, where they play important roles in the atmospheric composition, chemistry, dynamics and energetics. This dissertation focuses on a case-study of the propagation and dissipation characteristics of an inertial GW, the seasonal variation of the diurnal tide based on both the observations and models, and also the interactions between GWs and tides. One-night (October 28, 2003) temperature and horizontal wind measurements by a resonance sodium (Na) wind/temperature lidar in Maui (20.7 N, 156.3 W) and temperature measurement by a Rayleigh lidar at Mauna Loa Observatory (MLO, 19.5 N, 155.6 W), HI, are used as a case study of the GW propagation from the lower stratosphere to the lower thermosphere (35-103 km). A dominant wave mode is identi ed from the simultaneous temperature observations by both lidars. The wave is partially dissipated and propagates upward with an e-fold height of temperature amplitude at 14 km. A damping layer is present around the stratopause where the wave amplitude is relatively smaller, corresponding to a low static stability layer. The vertical wavelengths are larger in the mesosphere (12-13 km) than in the stratosphere (6-7 km), consistent with the decreasing static stability with altitude. The wave is propagating northward and the horizontal wavelength is 2140 km and intrinsic period is 15 hrs in the region of 84-103 km. The apparent period is 6 hrs and consistent with Doppler shift of the background wind. It is suggested that the convective zone over the equator to the south of Hawaii provides a constant GW source that is responsible for the observed GW throughout the night. The seasonal variability of the diurnal tide in the mesosphere and lower thermosphere (MLT) over Maui, HI is investigated using the meteor radar horizontal wind measurement from years 2002 to 2007. The semiannual oscillation (SAO) of tidal amplitudes is dominant above 88 km, with amplitudes at the equinoxes 2-3 times larger than at the solstices. Below 88 km, the annual oscillation (AO) dominates and its magnitude is smaller than the SAO. The AO dominates in the phase variation of the diurnal tide, which advances in winter and lags in summer as compared with the equinoxes. The vertical wavelength also has a noticeable seasonal variation with shorter vertical wavelengths found at the equinoxes. The reconstruction of the diurnal tide by superposing the migrating and nonmigrating tides derived from Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Doppler Interferometer (TIMED/TIDI) and TIMED/Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature is compared with the meteor radar observation, and a consistency is found in the seasonal variation of the tidal amplitude. Based on the TIDI and SABER measurements, the migrating diurnal tide (DW1) is the dominant tidal component while three other nonmigrating tides, DW2, DS0 and DE3, are non-negligible. The seasonal variation of the diurnal tide is well captured by the Global Scale Wave Model (GSWM) and the Whole Atmosphere Community Climate Model (WACCM) while discrepancies are also presented and discussed. Since the WACCM is capable of reproducing the tidal seasonality, it is used to examine the physical mechanisms. First, the e ects of GW forcing and advection on the momentum balance of DW1 are investigated, because they are the two most dominant terms in the momentum equation that account for the discrepancies between classical tidal theory and the calculations based on the full primitive equations. In the WACCM, GW forcing in the wave breaking region always damps DW1 and advances its phase, thus shortening the vertical wavelength of the tide locally. The linear advection largely determined by the latitudinal shear of the zonal mean wind mostly contributes to the phase change in the zonal wind. For the meridional wind, however, nonlinear advection is more important than GW drag and linear advection for the amplitude and phase changes. The DW1 amplitudes are smaller than TIMED observations, suggesting that the GW forcing is overestimated in the WACCM and result in an unrealistic large damping on DW1. Second, the seasonal variations of GW forcing, tidal heating and mean wind e ects are examined using the WACCM. Similar to the tidal amplitude, stronger GW forcing is also found at the equinox, which can not account for the tidal seasonality because GW forcing always damps DW1. Instead, the radiative tidal heating due to the water vapor absorption of infrared solar radiation largely determines the SAO of DW1. The e ffect of mean winds leads to a 1-month time shift of the maximum amplitude. The AO in the tidal phase is due to the seasonal change of mean winds. At the solstice, a stronger antisymmetric (1,2) Hough mode is generated which signi cantly distorts the tidal structure. Because the phase of the (1,2) mode changes by 12-hrs every half a year, it causes a phase advance in winter and a lag in summer, thus leading to an AO of the phase. As GWs and tides reach the MLT region, they can maintain large amplitudes thus strong interactions between them are expected. High-frequency GW variances are calculated as the residual horizontal wind variances based on the meteor radar measurements in Maui, HI and Urbana, IL (40 N, 88 W). Monte-Carlo simulations are performed in order to evaluate the sensitivity of the GW variance calculation on the meteor rate. It is indicated that the residual horizontal wind variance can be used as a good proxy of GW activities. The diurnal and semidiurnal variations of the GW variances are most dominant, while periods of 2-day, 5-day and 10-day are also observed. The vertical phase structures of the GW variances and tidal winds are consistent with each other, implying the GW variances are modulated by tides. In most cases, the GW variances increase with altitude and the growth rates are slower than freely propagating waves. A further study on the physical mechanisms resulting in the tidal modulations is needed in the future.

Download or read book Atmospheric Tides written by S. Chapman and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: Everyone is familiar with the daily changes of air temperature. The barometer shows that these are accompanied by daily changes of mass distribution of the atmosphere, and consequently with daily motions of the air. In the tropics the daily pressure change is evident on the barographs; in temperate and higher latitudes it is not noticeable, being overwhelmed by cyclonic and anticyclonic pressure variations. There too, however, the daily change can be found by averaging the variations over many days; and the same process suffices to show that there is a still smaller lunar tide in the atmosphere, first sought by Laplace. Throughout nearly two centuries these 'tides', thermal and gravitational, have been extensively discussed in the periodical literature of science, although they are very minor phenomena at ground level. This monograph summarizes our present knowledge and theoretical under standing of them. It is more than twenty years since the appearance of the one previous monograph on them - by Wilkes - and nearly a decade since they were last comprehensively reviewed, by Siebert. The intervening years have seen many additions to our know ledge of the state of the upper atmosphere, and of the tides there, on the basis of measurements by radio, rockets and satellites.

Download or read book A Numerical Study on the Interaction of Atmospheric Internal Gravity Waves and Cumulus Convection written by Jae-Kyung Eom Schemm and published by . This book was released on 1981 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Gravity Waves on Transient Heating Response of the Upper Atmosphere written by Yam T. Chiu and published by . This book was released on 1970 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is shown that the presence of gravity wave interaction with a transiently heated atmosphere changes the atmospheric response to heating significantly. The energy exchange between wave and ambient atmosphere manifests itself as an apparent increase in effective thermal diffusivity. The present model predicts altitude independent (

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 The Interaction of Ocean Waves and Wind written by Peter Janssen and published by Cambridge University Press. This book was released on 2004-10-28 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book was published in 2004. The Interaction of Ocean Waves and Wind describes in detail the two-way interaction between wind and ocean waves and shows how ocean waves affect weather forecasting on timescales of 5 to 90 days. Winds generate ocean waves, but at the same time airflow is modified due to the loss of energy and momentum to the waves; thus, momentum loss from the atmosphere to the ocean depends on the state of the waves. This volume discusses ocean wave evolution according to the energy balance equation. An extensive overview of nonlinear transfer is given, and as a by-product the role of four-wave interactions in the generation of extreme events, such as freak waves, is discussed. Effects on ocean circulation are described. Coupled ocean-wave, atmosphere modelling gives improved weather and wave forecasts. This volume will interest ocean wave modellers, physicists and applied mathematicians, and engineers interested in shipping and coastal protection.

Download or read book Studies of Gravity wave Filtering and Tidal Interaction in the Middle Atmosphere Wentong Lu written by Wentong Lu and published by . This book was released on 1993 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Gravity wave Filtering and Tidal Interaction in the Middle Atmosphere written by Wentong Lu and published by . This book was released on 1993 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Transfers in Atmosphere and Ocean written by Carsten Eden and published by Springer. This book was released on 2019-01-23 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes a recent effort combining interdisciplinary expertise within the Collaborative Research Centre “Energy transfers in atmosphere and ocean” (TRR-181), which was funded by the German Research Foundation (DFG). Energy transfers between the three dynamical regimes – small-scale turbulence, internal gravity waves and geostrophically balanced motion – are fundamental to the energy cycle of both the atmosphere and the ocean. Nonetheless, they remain poorly understood and quantified, and have yet to be adequately represented in today’s climate models. Since interactions between the dynamical regimes ultimately link the smallest scales to the largest ones through a range of complex processes, understanding these interactions is essential to constructing atmosphere and ocean models and to predicting the future climate. To this end, TRR 181 combines expertise in applied mathematics, meteorology, and physical oceanography. This book provides an overview of representative specific topics addressed by TRR 181, ranging from - a review of a coherent hierarchy of models using consistent scaling and approximations, and revealing the underlying Hamiltonian structure - a systematic derivation and implementation of stochastic and backscatter parameterisations - an exploration of the dissipation of large-scale mean or eddying balanced flow and ocean eddy parameterisations; and - a study on gravity wave breaking and mixing, the interaction of waves with the mean flow and stratification, wave-wave interactions and gravity wave parameterisations to topics of a more numerical nature such as the spurious mixing and dissipation of advection schemes, and direct numerical simulations of surface waves at the air-sea interface. In TRR 181, the process-oriented topics presented here are complemented by an operationally oriented synthesis focusing on two climate models currently being developed in Germany. In this way, the goal of TRR 181 is to help reduce the biases in and increase the accuracy of atmosphere and ocean models, and ultimately to improve climate models and climate predictions.

Download or read book THE INTERACTION OF INTERNAL GRAVITY WAVES AND ATMOSPHERIC WINDS WITH SHEAR written by KEITH LAVERNE BEKOFSKE and published by . This book was released on 1972 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Solar and Space Physics written by National Research Council and published by National Academies Press. This book was released on 2014-09-25 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2010, NASA and the National Science Foundation asked the National Research Council to assemble a committee of experts to develop an integrated national strategy that would guide agency investments in solar and space physics for the years 2013-2022. That strategy, the result of nearly 2 years of effort by the survey committee, which worked with more than 100 scientists and engineers on eight supporting study panels, is presented in the 2013 publication, Solar and Space Physics: A Science for a Technological Society. This booklet, designed to be accessible to a broader audience of policymakers and the interested public, summarizes the content of that report.

Download or read book The Detection of Atmospheric Gravity Waves by Means of the Wave Interaction Experiment written by Michael Peter Sulzer and published by . This book was released on 1979 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Climate and Weather of the Sun Earth System CAWSES written by Franz-Josef Lübken and published by Springer Science & Business Media. This book was released on 2012-08-14 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: CAWSES (Climate and Weather of the Sun-Earth System) is the most important scientific program of SCOSTEP (Scientific Committee on Solar-Terrestrial Physics). CAWSES has triggered a scientific priority program within the German Research Foundation for a period of 6 years. Approximately 30 scientific institutes and 120 scientists were involved in Germany with strong links to international partners. The priority program focuses on solar influence on climate, atmospheric coupling processes, and space climatology. This book summarizes the most important results from this program covering some important research topics from the Sun to climate. Solar related processes are studied including the evolution of solar radiation with relevance to climate. Results regarding the influence of the Sun on the terrestrial atmosphere from the troposphere to the thermosphere are presented including stratospheric ozone, mesospheric ice clouds, geomagnetic effects, and their relevance to climate. Several chapters highlight the importance of coupling mechanisms within the atmosphere, covering transport mechanisms of photochemically active species, dynamical processes such as gravity waves, tides, and planetary waves, and feedback mechanisms between the thermal and dynamical structure of the atmosphere. Special attention is paid to climate signals in the middle and upper atmosphere and their significance relative to natural variability.

Download or read book Atmospheric Dynamics written by Ulrich Achatz and published by Springer Nature. This book was released on 2022-03-04 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook is intended for both undergraduate and graduate courses in meteorology and atmospheric sciences, as well as for researchers working on theoretical and numerical aspects of weather and climate or on geophysical fluid dynamics. The treatment is concise, thorough, and self-contained. All necessary concepts are introduced, and the reader is given explicit guidance on all mathematical steps. The book begins with a derivation of the equations of motion. These are then used to discuss fundamental aspects of weather and climate. The mechanisms behind vortical motions, that are known from the daily weather map, are discussed. Shallow-water theory is introduced as a tool for an efficient analysis of key concepts, such as atmospheric waves and synoptic-scale vortices. Quasigeostrophic theory is described and then used to explain the occurrence and mechanisms of extratropical weather by means of baroclinic instability. The specific properties of the atmospheric boundary layer are discussed, with a focus on the interaction between turbulence and mean flows. This is followed by a detailed look at the global atmospheric circulation, highlighting its control by Rossby waves and gravity waves. At the same time, the reader is introduced to essential concepts that find applications in the field, such as balance by geostrophic and hydrostatic equilibrium, the role of entropy and potential temperature, potential vorticity, the Kelvin theorem, instability theory, the Reynolds equations, Eliassen-Palm and pseudo-momentum flux, multi-scale asymptotics, WKB theory, wave action, the transformed Eulerian mean, critical layers, and wave refraction. The text is supplemented by appendices on important mathematical concepts and further elaborations of the main text. Chapter summaries and reading recommendations help the reader not merely to keep focus on the essentials, but just as well to broaden the horizon.

Download or read book An Investigation of the Interaction Between Turbulence and Propagating Internal Gravity Waves the Planetary Boundary Layer written by Franco Einaudi and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: