scholarly journals Estimation of Gravity Wave Momentum Flux and Phase Speeds from Quasi-Lagrangian Stratospheric Balloon Flights. Part I: Theory and Simulations

2008 ◽  
Vol 65 (10) ◽  
pp. 3042-3055 ◽  
Author(s):  
Gillian Boccara ◽  
Albert Hertzog ◽  
Robert A. Vincent ◽  
François Vial
Keyword(s):  
Gravity Wave ◽  
Wave Packets ◽  
Phase Speed ◽  
Companion Paper ◽  
Time Frequency ◽  
Long Duration ◽  
Short Period ◽  
Momentum Fluxes ◽  
Stratospheric Balloon ◽  
Wave Momentum

A methodology for estimating gravity wave characteristics from quasi-Lagrangian observations provided by long-duration, superpressure balloon flights in the stratosphere is reviewed. Wavelet analysis techniques are used to detect gravity wave packets in observations of pressure, temperature, and horizontal velocity. An emphasis is put on the estimation of gravity wave momentum fluxes and intrinsic phase speeds, which are generally poorly known on global scales in the atmosphere. The methodology is validated using Monte Carlo simulations of time series that mimic the balloon measurements, including the uncertainties associated with each of the meteorological parameters. While the azimuths of the wave propagation direction are accurately retrieved, the momentum fluxes are generally slightly underestimated, especially when wave packets overlap in the time–frequency domain, or for short-period waves. A proxy is derived to estimate by how much momentum fluxes are reduced by the analysis. Retrievals of intrinsic phase speeds are less accurate, especially for low phase speed waves. A companion paper (Part II) implements the methodology to observations gathered during the Vorcore campaign that took place in Antarctica between September 2005 and February 2006.

Estimation of Gravity Wave Momentum Flux and Phase Speeds from Quasi-Lagrangian Stratospheric Balloon Flights. Part II: Results from the Vorcore Campaign in Antarctica

2008 ◽  
Vol 65 (10) ◽  
pp. 3056-3070 ◽  
Author(s):  
Albert Hertzog ◽  
Gillian Boccara ◽  
Robert A. Vincent ◽  
François Vial ◽  
Philippe Cocquerez
Keyword(s):  
Gravity Wave ◽  
Momentum Flux ◽  
General Circulation ◽  
General Circulation Models ◽  
Companion Paper ◽  
Wave Drag ◽  
Mountain Waves ◽  
Long Duration ◽  
Momentum Fluxes ◽  
Wave Momentum

The stratospheric gravity wave field in the Southern Hemisphere is investigated by analyzing observations collected by 27 long-duration balloons that flew between September 2005 and February 2006 over Antarctica and the Southern Ocean. The analysis is based on the methods introduced by Boccara et al. in a companion paper. Special attention is given to deriving information useful to gravity wave drag parameterizations employed in atmospheric general circulation models. The balloon dataset is used to map the geographic variability of gravity wave momentum fluxes in the lower stratosphere. This flux distribution is found to be very heterogeneous with the largest time-averaged value (28 mPa) observed above the Antarctic Peninsula. This value exceeds by a factor of ∼10 the overall mean momentum flux measured during the balloon campaign. Zonal momentum fluxes were predominantly westward, whereas meridional momentum fluxes were equally northward and southward. A local enhancement of southward flux is nevertheless observed above Adélie Land and is attributed to waves generated by katabatic winds, for which the signature is otherwise rather small in the balloon observations. When zonal averages are performed, oceanic momentum fluxes are found to be of similar magnitude to continental values (2.5–3 mPa), stressing the importance of nonorographic gravity waves over oceans. Last, gravity wave intermittency is investigated. Mountain waves appear to be significantly more sporadic than waves observed above the ocean.

Short period gravity wave momentum fluxes observed in the tropical troposphere, stratosphere and mesosphere

2013 ◽  
Vol 105-106 ◽  
pp. 1-7 ◽  
Author(s):  
S. Eswaraiah ◽  
M. Venkat Ratnam ◽  
B.V. Krishna Murthy ◽  
A. Guharay ◽  
S. Vijaya Bhaskara Rao
Keyword(s):  
Gravity Wave ◽  
Short Period ◽  
Momentum Fluxes ◽  
Tropical Troposphere ◽  
Wave Momentum

Gravity wave momentum fluxes in the MLT—Part II: Meteor radar investigations at high and midlatitudes in comparison with modeling studies

2011 ◽  
Vol 73 (9) ◽  
pp. 911-920 ◽  
Author(s):  
Manja Placke ◽  
Peter Hoffmann ◽  
Erich Becker ◽  
Christoph Jacobi ◽  
Werner Singer ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Meteor Radar ◽  
Modeling Studies ◽  
Momentum Fluxes ◽  
Wave Momentum

scholarly journals Quantifying gravity wave momentum fluxes with Mesosphere Temperature Mappers and correlative instrumentation

2014 ◽  
Vol 119 (24) ◽  
pp. 13,583-13,603 ◽  
Author(s):  
David C. Fritts ◽  
P.-Dominique Pautet ◽  
Katrina Bossert ◽  
Michael J. Taylor ◽  
Bifford P. Williams ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Momentum Fluxes ◽  
Wave Momentum

scholarly journals Improved analysis of all-sky meteor radar measurements of gravity wave variances and momentum fluxes

2013 ◽  
Vol 31 (5) ◽  
pp. 889-908 ◽  
Author(s):  
V. F. Andrioli ◽  
D. C. Fritts ◽  
P. P. Batista ◽  
B. R. Clemesha
Keyword(s):  
Gravity Wave ◽  
Good Accuracy ◽  
Test Results ◽  
Empirical Correction ◽  
Simple Simulation ◽  
Momentum Fluxes ◽  
Simple Change ◽  
Radar Measurements ◽  
Wave Momentum

Abstract. The advantages of using a composite day analysis for all-sky interferometric meteor radars when measuring mean winds and tides are widely known. On the other hand, problems arise if this technique is applied to Hocking's (2005) gravity wave analysis for all-sky meteor radars. In this paper we describe how a simple change in the procedure makes it possible to use a composite day in Hocking's analysis. Also, we explain how a modified composite day can be constructed to test its ability to measure gravity wave momentum fluxes. Test results for specified mean, tidal, and gravity wave fields, including tidal amplitudes and gravity wave momentum fluxes varying strongly with altitude and/or time, suggest that the modified composite day allows characterization of monthly mean profiles of the gravity wave momentum fluxes, with good accuracy at least at the altitudes where the meteor counts are large (from 89 to 92.5 km). In the present work we also show that the variances measured with Hocking's method are often contaminated by the tidal fields and suggest a method of empirical correction derived from a simple simulation model. The results presented here greatly increase our confidence because they show that our technique is able to remove the tide-induced false variances from Hocking's analysis.

scholarly journals Comparison of gravity wave momentum fluxes estimated by different methods using mesosphere-stratosphere-troposphere radar

Radio Science ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Gopa Dutta ◽  
B. Bapiraju ◽  
P. V. Rao ◽  
A. I. Sheeba ◽  
M. C. Ajay Kumar ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Momentum Fluxes ◽  
Wave Momentum

scholarly journals A Comparison between Gravity Wave Momentum Fluxes in Observations and Climate Models

2013 ◽  
Vol 26 (17) ◽  
pp. 6383-6405 ◽  
Author(s):  
Marvin A. Geller ◽  
M. Joan Alexander ◽  
Peter T. Love ◽  
Julio Bacmeister ◽  
Manfred Ern ◽  
...  
Keyword(s):  
High Resolution ◽  
Gravity Wave ◽  
Gravity Waves ◽  
Climate Models ◽  
Radiosonde Data ◽  
Wave Source ◽  
Wide Range ◽  
Momentum Fluxes ◽  
High Resolution Models ◽  
Wave Momentum

Abstract For the first time, a formal comparison is made between gravity wave momentum fluxes in models and those derived from observations. Although gravity waves occur over a wide range of spatial and temporal scales, the focus of this paper is on scales that are being parameterized in present climate models, sub-1000-km scales. Only observational methods that permit derivation of gravity wave momentum fluxes over large geographical areas are discussed, and these are from satellite temperature measurements, constant-density long-duration balloons, and high-vertical-resolution radiosonde data. The models discussed include two high-resolution models in which gravity waves are explicitly modeled, Kanto and the Community Atmosphere Model, version 5 (CAM5), and three climate models containing gravity wave parameterizations, MAECHAM5, Hadley Centre Global Environmental Model 3 (HadGEM3), and the Goddard Institute for Space Studies (GISS) model. Measurements generally show similar flux magnitudes as in models, except that the fluxes derived from satellite measurements fall off more rapidly with height. This is likely due to limitations on the observable range of wavelengths, although other factors may contribute. When one accounts for this more rapid fall off, the geographical distribution of the fluxes from observations and models compare reasonably well, except for certain features that depend on the specification of the nonorographic gravity wave source functions in the climate models. For instance, both the observed fluxes and those in the high-resolution models are very small at summer high latitudes, but this is not the case for some of the climate models. This comparison between gravity wave fluxes from climate models, high-resolution models, and fluxes derived from observations indicates that such efforts offer a promising path toward improving specifications of gravity wave sources in climate models.

Sign in / Sign up

Export Citation Format

Share Document