Seasonal variation of gravity wave activity at 5-20 km observed with VHF radar at White Sands Missile Range, New Mexico

2001 ◽  
Vol 106 (D15) ◽  
pp. 17171-17183 ◽  
Author(s):  
Anthony R. Hansen ◽  
Gregory D. Nastrom ◽  
Frank D. Eaton
Keyword(s):  
Seasonal Variation ◽  
New Mexico ◽  
Gravity Wave ◽  
Wave Activity ◽  
Vhf Radar ◽  
White Sands

scholarly journals Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E)

2001 ◽  
Vol 19 (8) ◽  
pp. 1019-1025 ◽  
Author(s):  
M. N. Sasi ◽  
L. Vijayan
Keyword(s):  
Seasonal Variation ◽  
Gravity Wave ◽  
Middle Atmosphere ◽  
Indian Subcontinent ◽  
Southwest Monsoon ◽  
Wave Activity ◽  
Tropical Meteorology ◽  
Monsoon Period ◽  
Mst Radar ◽  
Summer Maximum

Abstract. Turbulent kinetic energy dissipation rates (ε) and eddy diffusion coefficients (Kz) in the tropical mesosphere over Gadanki (13.5° N, 79.2° E), estimated from Doppler widths of MST radar echoes (vertical beam), observed over a 3-year period, show a seasonal variation with a dominant summer maximum. The observed seasonal variation of ε and Kz in the mesosphere is only partially consistent with that of gravity wave activity inferred from mesospheric winds and temperatures measured by rockets for a period of 9 years at Trivandrum (8.5° N, 77° E) (which shows two equinox and one summer maxima) lying close to Gadanki. The summer maximum of mesospheric ε and Kz values appears to be related to the enhanced gravity wave activity over the low-latitude Indian subcontinent during the southwest monsoon period (June – September). Both ε and Kz in the mesosphere over Gadanki show an increase with an increase in height during all seasons. The absolute values of observed ε and Kz in the mesosphere (above ~80 km) does not show significant differences from those reported for high latitudes. Comparison of observed Kz values during the winter above Gadanki with those over Arecibo (18.5° N, 66° W) shows that they are not significantly different from each other above the ~80 km altitude.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; tropical meteorology; wave and tides)

scholarly journals Seasonal variation of short-period (<2 h) gravity wave activity over Gadanki, India (13.5°N, 79.2°E)

2008 ◽  
Vol 113 (D14) ◽  
Author(s):  
Gopa Dutta ◽  
Toshitaka Tsuda ◽  
P. Vinay Kumar ◽  
M. C. Ajay Kumar ◽  
Simon P. Alexander ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Gravity Wave ◽  
Wave Activity ◽  
Period 2 ◽  
Short Period

scholarly journals Seasonal variation of gravity waves in the Equatorial Middle Atmosphere: results from ISRO's Middle Atmospheric Dynamics (MIDAS) program

2006 ◽  
Vol 24 (10) ◽  
pp. 2471-2480 ◽  
Author(s):  
G. Ramkumar ◽  
T. M. Antonita ◽  
Y. Bhavani Kumar ◽  
H. Venkata Kumar ◽  
D. Narayana Rao
Keyword(s):  
Seasonal Variation ◽  
Gravity Wave ◽  
Gravity Waves ◽  
Wind Shear ◽  
Middle Atmosphere ◽  
Wave Activity ◽  
Atmospheric Dynamics ◽  
Horizontal Wind ◽  
Middle Atmospheric Dynamics ◽  
Radar Measurements

Abstract. Altitude profiles of temperature in the stratospheric and mesopheric region from lidar observations at NARL, Gadanki, India, during December 2002–April 2005, as part of ISRO's Middle Atmospheric Dynamics – "MIDAS (2002–2005)" program are used to study the characteristics of gravity waves and their seasonal variation. Month-to-month variation of the gravity wave activity observed during the period of December 2002–April 2005 show maximum wave activity, with primary peaks in May 2003, August 2004 and March 2005 and secondary peaks in February 2003 and November 2004. This month-to-month variation in gravity wave activity is linked to the variation in the strength of the sources, viz. convection and wind shear, down below at the tropospheric region, estimated from MST radar measurements at the same location. Horizontal wind shear is found to be mostly correlated with wave activity than convection, and sometimes both sources are found to contribute towards the wave activity.

scholarly journals Inertia gravity waves in the upper troposphere during the MaCWAVE winter campaign – Part II: Radar investigations and modelling studies

2006 ◽  
Vol 24 (11) ◽  
pp. 2863-2875 ◽  
Author(s):  
A. Serafimovich ◽  
Ch. Zülicke ◽  
P. Hoffmann ◽  
D. Peters ◽  
P. Dalin ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Mesoscale Model ◽  
Wave Activity ◽  
Model Data ◽  
Vhf Radar ◽  
Upper Troposphere ◽  
Radar Measurements ◽  
Horizontal Momentum ◽  
Inertia Gravity Waves

Abstract. We present an experimental and modelling study of a strong gravity wave event in the upper troposphere/lower stratosphere near the Scandinavian mountain ridge. Continuous VHF radar measurements during the MaCWAVE rocket and ground-based measurement campaign were performed at the Norwegian Andoya Rocket Range (ARR) near Andenes (69.3° N, 16° E) in January 2003. Detailed gravity wave investigations based on PSU/NCAR Fifth-Generation Mesoscale Model (MM5) data have been used for comparison with experimentally obtained results. The model data show the presence of a mountain wave and of an inertia gravity wave generated by a jet streak near the tropopause region. Temporal and spatial dependencies of jet induced inertia gravity waves with dominant observed periods of about 13 h and vertical wavelengths of ~4.5–5 km are investigated with wavelet transform applied on radar measurements and model data. The jet induced wave packet is observed to move upstream and downward in the upper troposphere. The model data agree with the experimentally obtained results fairly well. Possible reasons for the observed differences, e.g. in the time of maximum of the wave activity, are discussed. Finally, the vertical fluxes of horizontal momentum are estimated with different methods and provide similar amplitudes. We found indications that the derived positive vertical flux of the horizontal momentum corresponds to the obtained parameters of the jet-induced inertia gravity wave, but only at the periods and heights of the strongest wave activity.

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