[1] Atmospheric gravity waves have been a subject of intense research activity in recent years because of their myriad effects and their major contributions to atmospheric circulation, structure, and variability. Apart from occasionally strong lower-atmospheric effects, the major wave influences occur in the middle atmosphere, between ∼ 10 and 110 km altitudes because of decreasing density and increasing wave amplitudes with altitude. Theoretical, numerical, and observational studies have advanced our understanding of gravity waves on many fronts since the review by Fritts [1984a]; the present review will focus on these more recent contributions. Progress includes a better appreciation of gravity wave sources and characteristics, the evolution of the gravity wave spectrum with altitude and with variations of wind and stability, the character and implications of observed climatologies, and the wave interaction and instability processes that constrain wave amplitudes and spectral shape. Recent studies have also expanded dramatically our understanding of gravity wave influences on the large-scale circulation and the thermal and constituent structures of the middle atmosphere. These advances have led to a number of parameterizations of gravity wave effects which are enabling ever more realistic descriptions of gravity wave forcing in large-scale models. There remain, nevertheless, a number of areas in which further progress is needed in refining our understanding of and our ability to describe and predict gravity wave influences in the middle atmosphere. Our view of these unknowns and needs is also offered.

/pdf/gravity-wave-dynamics-and-effects-in-the-middle-atmosphere-4huexaq7y8.pdf

Gravity wave dynamics and effects in the middle atmosphere

https://www.lpl.arizona.edu/~yelle/eprints/Yelle04b.pdf

Aeronomy of extra-solar giant planets at small orbital distances

Atmosphere: State of the Art and Challenges Barbara Nozier̀e,*,† Markus Kalberer,*,‡ Magda Claeys,* James Allan, Barbara D’Anna,† Stefano Decesari, Emanuela Finessi, Marianne Glasius, Irena Grgic,́ Jacqueline F. Hamilton, Thorsten Hoffmann, Yoshiteru Iinuma, Mohammed Jaoui, Ariane Kahnt, Christopher J. Kampf, Ivan Kourtchev,‡ Willy Maenhaut, Nicholas Marsden, Sanna Saarikoski, Jürgen Schnelle-Kreis, Jason D. Surratt, Sönke Szidat, Rafal Szmigielski, and Armin Wisthaler †Ircelyon/CNRS and Universite ́ Lyon 1, 69626 Villeurbanne Cedex, France ‡University of Cambridge, Cambridge CB2 1EW, United Kingdom University of Antwerp, 2000 Antwerp, Belgium The University of Manchester & National Centre for Atmospheric Science, Manchester M13 9PL, United Kingdom Istituto ISAC C.N.R., I-40129 Bologna, Italy University of York, York YO10 5DD, United Kingdom University of Aarhus, 8000 Aarhus C, Denmark National Institute of Chemistry, 1000 Ljubljana, Slovenia Johannes Gutenberg-Universitaẗ, 55122 Mainz, Germany Leibniz-Institut für Troposphar̈enforschung, 04318 Leipzig, Germany Alion Science & Technology, McLean, Virginia 22102, United States Max Planck Institute for Chemistry, 55128 Mainz, Germany Ghent University, 9000 Gent, Belgium Finnish Meteorological Institute, FI-00101 Helsinki, Finland Helmholtz Zentrum München, D-85764 Neuherberg, Germany University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States University of Bern, 3012 Bern, Switzerland Institute of Physical Chemistry PAS, Warsaw 01-224, Poland University of Oslo, 0316 Oslo, Norway

/pdf/the-molecular-identification-of-organic-compounds-in-the-1rs6wk4d8f.pdf

The molecular identification of organic compounds in the atmosphere : state of the art and challenges

Global warming is expected to drive increasing extreme sea levels (ESLs) and flood risk along the world's coastlines. In this work we present probabilistic projections of ESLs for the present century taking into consideration changes in mean sea level, tides, wind-waves, and storm surges. Between the year 2000 and 2100 we project a very likely increase of the global average 100-year ESL of 34-76 cm under a moderate-emission-mitigation-policy scenario and of 58-172 cm under a business as usual scenario. Rising ESLs are mostly driven by thermal expansion, followed by contributions from ice mass-loss from glaciers, and ice-sheets in Greenland and Antarctica. Under these scenarios ESL rise would render a large part of the tropics exposed annually to the present-day 100-year event from 2050. By the end of this century this applies to most coastlines around the world, implying unprecedented flood risk levels unless timely adaptation measures are taken.

/pdf/global-probabilistic-projections-of-extreme-sea-levels-show-1suozfqs6n.pdf

Global probabilistic projections of extreme sea levels show intensification of coastal flood hazard.

Forcing of the ionosphere by waves from below

A compressible numerical model is applied for three‐dimensional (3‐D) gravity wave (GW) packets undergoing momentum deposition, self‐acceleration (SA), breaking, and secondary GW (SGW) generation in the presence of highly‐structured environments enabling thermal and/or Doppler ducts, such as a mesospheric inversion layer (MIL), tidal wind (TW), or combination of MIL and TW. Simulations reveal that ducts can strongly modulate GW dynamics. Responses modeled here include reflection, trapping, suppressed transmission, strong local instabilities, reduced SGW generations, higher altitude SGW responses, and induced large‐scale flows. Instabilities that arise in ducts experience strong dissipation after they emerge, while trapped smaller‐amplitude and smaller‐scale GWs can survive in ducts to much later times. Additionally, GW breaking and its associated dynamics enhance the local wind along the GW propagation direction in the ducts, and yield layering in the wind field. However, these dynamics do not yield significant heat transport in the ducts. The failure of GW breaking to induce stratified layers in the temperature field suggests that such heat transport might not be as strong as previously assumed or inferred from observations and theoretical assessments. The present numerical simulations confirm previous finding that MIL generation may not be caused by the breaking of a transient high‐frequency GW packet alone.

Modeling Studies of Gravity Wave Dynamics in Highly Structured Environments: Reflection, Trapping, Instability, Momentum Transport, Secondary Gravity Waves, and Induced Flow Responses

We simulate space-based, sublimb viewing observations of airglow brightness fluctuations caused by atmospheric gravity wave interactions with the O2 atmospheric airglow, and we demonstrate that because of the geometry associated with such observations, the brightness fluctuations observed for the optically thick 0–0 band emission will always appear stronger for waves traveling toward the observer (the satellite). The effect should be most noticeable for waves having relatively small vertical wavelengths (∼10 km) and horizontal wavelengths of 50 km or greater. For waves of short (∼100 km) horizontal wavelength, the brightness fluctuation anisotropy with respect to viewing direction may also be evident in the optically thin 0–1 band emission. We demonstrate that the waves will be observable despite the fact that an instrument requires a certain finite integration time to achieve a desired signal-to-noise ratio. Therefore the 180° ambiguity in wave propagation direction associated with space-based observations may be eliminated for waves of small vertical wavelength that are dissipating in the upper mesosphere and lower thermosphere. It is these same waves that may be expected to be important to the energy and momentum budgets of the mesosphere/lower thermosphere region.

/pdf/gravity-wave-propagation-directions-inferred-from-satellite-2fpoueaseg.pdf

Gravity Wave Propagation Directions Inferred from Satellite Observations including Smearing Effects

Gravity Wave Heating and Cooling in Saturn's Thermosphere

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2002JD002446

Correction to “Full-wave modeling of small-scale gravity waves using Airborne Lidar and Observations of the Hawaiian Airglow (ALOHA-93) O(1S) images and coincident Na wind/temperature lidar measurements” by Michael P. Hickey et al.

Michael P. Hickey

Papers

Modeling Studies of Gravity Wave Dynamics in Highly Structured Environments: Reflection, Trapping, Instability, Momentum Transport, Secondary Gravity Waves, and Induced Flow Responses

Gravity Wave Propagation Directions Inferred from Satellite Observations including Smearing Effects

Gravity Wave Heating and Cooling in Saturn's Thermosphere

Correction to “Full-wave modeling of small-scale gravity waves using Airborne Lidar and Observations of the Hawaiian Airglow (ALOHA-93) O(1S) images and coincident Na wind/temperature lidar measurements” by Michael P. Hickey et al.

Acoustic Wave Dissipation and Heating of Jupiter's Thermosphere