scholarly journals Quasi-monochromatic inertia-gravity waves in the lower stratosphere from MST radar observations

2006 ◽  
Vol 111 (D19) ◽  
Author(s):  
G. D. Nastrom ◽  
F. D. Eaton
2017 ◽  
Vol 9 (3) ◽  
pp. 284-293 ◽  
Author(s):  
Ajil Kottayil ◽  
Karathazhiyath Satheesan ◽  
Kesavapillai Mohankumar ◽  
Sivan Chandran ◽  
Titu Samson

1984 ◽  
Vol 41 (15) ◽  
pp. 2359-2367 ◽  
Author(s):  
Yasuyuki Maekawa ◽  
Shoichiro Fukao ◽  
Toru Sato ◽  
Susumu Kato ◽  
Ronald F. Woodman

2012 ◽  
Vol 12 (22) ◽  
pp. 11085-11093 ◽  
Author(s):  
Z. Li ◽  
S. Naqvi ◽  
A. J. Gerrard ◽  
J. L. Chau ◽  
Y. Bhattacharya

Abstract. Persistent wind jet structures along zonal and meridional fields, believed to be caused by stationary gravity waves, were detected in February 1999 in mesosphere-stratosphere-troposphere (MST) radar wind measurements of the troposphere and lower stratosphere over Jicamarca, Peru. Over a continuous seven day span of MST-data analyzed in this study, two days of observations showed signatures of wave-like structures in the upper troposphere/lower stratosphere wind jets associated with the phases of the stationary gravity waves. We believe these wave-like structures are ducted gravity waves. We present these initial observations, their characteristics, and the results of simple numerical simulations used in an attempt to mimic these observed features. Although a fair replication of the observed ducted structure in the numerical model is found, the observed period of ~90 min is nonetheless much longer than what is traditionally observed. As a result, the specific physical nature of the observed structures is not fully established. Nevertheless, given the high quality of the observations, we demonstrate here that continued analysis of this data set and concurrent modeling efforts will allow for a better understanding of Doppler ducts at high spatial and temporal resolution, and the results presented here can ultimately be applied to studies of middle atmospheric fronts, ducts, and bores.


2015 ◽  
Vol 72 (5) ◽  
pp. 2109-2130 ◽  
Author(s):  
Ryosuke Shibuya ◽  
Kaoru Sato ◽  
Yoshihiro Tomikawa ◽  
Masaki Tsutsumi ◽  
Toru Sato

Abstract Multiple tropopauses (MTs) defined by the World Meteorological Organization are frequently detected from autumn to spring at Syowa Station (69.0°S, 39.6°E). The dynamical mechanism of MT events was examined by observations of the first mesosphere–stratosphere–troposphere (MST) radar in the Antarctic, the Program of the Antarctic Syowa MST/Incoherent Scatter (IS) Radar (PANSY), and of radiosondes on 8–11 April 2013. The MT structure above the first tropopause is composed of strong temperature fluctuations. By a detailed analysis of observed three-dimensional wind and temperature fluctuation components, it is shown that the phase and amplitude relations between these components are consistent with the theoretical characteristics of linear inertia–gravity waves (IGWs). Numerical simulations were performed by using a nonhydrostatic model. The simulated MT structures and IGW parameters agree well with the observation. In the analysis using the numerical simulation data, it is seen that IGWs were generated around 65°S, 15°E and around 70°S, 15°E, propagated eastward, and reached the region above Syowa Station when the MT event was observed. These IGWs were likely radiated spontaneously from the upper-tropospheric flow around 65°S, 15°E and were forced by strong southerly surface winds over steep topography (70°S, 15°E). The MT occurrence is attributable to strong IGWs and the low mean static stability in the polar winter lower stratosphere. It is also shown that nonorographic gravity waves associated with the tropopause folding event contribute to 40% of the momentum fluxes, as shown by a gravity wave–resolving general circulation model in the lower stratosphere around 65°S. This result indicates that they are one of the key components for solving the cold-bias problem found in most climate models.


1999 ◽  
Vol 17 (1) ◽  
pp. 115-121 ◽  
Author(s):  
L. Thomas ◽  
R. M. Worthington ◽  
A. J. McDonald

Abstract. Radar measurements at Aberystwyth (52.4° N, 4.1° W) of winds at tropospheric and lower stratospheric heights are shown for 12-13 March 1994 in a region of highly curved flow, downstream of the jet maximum. The perturbations of horizontal velocity have comparable amplitudes in the troposphere and lower stratosphere with downward and upward phase propagation, respectively, in these two height regions. The sense of rotation with increasing height in hodographs of horizontal perturbation velocity derived for hourly intervals show downwards propagation of energy in the troposphere and upward propagation in the lower stratosphere with vertical wavelengths of 1.7 to 2.3 km. The results indicate inertia-gravity waves propagating in a direction similar to that of the jet stream but at smaller velocities. Some of the features observed contrast with those of previous observations of inertia-gravity waves propagating transverse to the jet stream. The interpretation of the hodographs to derive wave parameters has taken account of the vertical shear of the background wind transverse to the direction of wave propagation.Key words. Meteorology and atmospheric dynamics (mesoscale meteorology; middle atmosphere dynamics; waves and tides)


2007 ◽  
Vol 133 (S2) ◽  
pp. 179-188 ◽  
Author(s):  
G. Vaughan ◽  
R. M. Worthington

2019 ◽  
Vol 53 (5-6) ◽  
pp. 2887-2903 ◽  
Author(s):  
N. Koushik ◽  
Karanam Kishore Kumar ◽  
K. V. Subrahmanyam ◽  
Geetha Ramkumar ◽  
I. A. Girach ◽  
...  

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