MST radar investigation on inertia-gravity waves associated with tropical depression in the upper troposphere and lower stratosphere over Gadanki (13.5°N, 79.2°E)

2010 ◽  
Vol 72 (16) ◽  
pp. 1184-1194 ◽  
Author(s):  
Siddarth Shankar Das ◽  
Karanam Kishore Kumar ◽  
K.N. Uma
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Upper Troposphere ◽  
Tropical Depression ◽  
Mst Radar ◽  
Inertia Gravity Waves

An investigation into the characteristics of inertia gravity waves in the upper troposphere/lower stratosphere using a 205 MHz wind profiling radar

2017 ◽  
Vol 9 (3) ◽  
pp. 284-293 ◽  
Author(s):  
Ajil Kottayil ◽  
Karathazhiyath Satheesan ◽  
Kesavapillai Mohankumar ◽  
Sivan Chandran ◽  
Titu Samson
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Upper Troposphere ◽  
Inertia Gravity Waves

scholarly journals Initial MST radar observations of upper tropospheric-lower stratospheric duct-like structures over Jicamarca, Peru

2012 ◽  
Vol 12 (22) ◽  
pp. 11085-11093 ◽  
Author(s):  
Z. Li ◽  
S. Naqvi ◽  
A. J. Gerrard ◽  
J. L. Chau ◽  
Y. Bhattacharya
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Physical Nature ◽  
High Quality ◽  
Data Set ◽  
Upper Troposphere ◽  
Atmospheric Fronts ◽  
Mst Radar ◽  
Wind Measurements

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.

scholarly journals Investigation of inertia-gravity waves in the upper troposphere/lower stratosphere over northern Germany observed with collocated VHF/UHF radars

2004 ◽  
Vol 4 (4) ◽  
pp. 4339-4381 ◽  
Author(s):  
A. Serafimovich ◽  
P. Hoffmann ◽  
D. Peters ◽  
V. Lehmann
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Wave Parameter ◽  
Data Sets ◽  
Northern Germany ◽  
Vhf Radar ◽  
Upper Troposphere ◽  
Rossby Wave Breaking ◽  
Uhf Wind Profiler ◽  
Inertia Gravity Waves

Abstract. A case study to investigate the properties of inertia-gravity waves in the upper troposphere/lower stratosphere has been carried out over Northern Germany during the occurrence of an upper tropospheric jet in connection with a poleward Rossby wave breaking event from 17-19 December 1999. The investigations are based on continuous radar measurements with the OSWIN VHF radar at Kühlungsborn (54.1° N, 11.8° E) and the 482 MHz UHF wind profiler at Lindenberg (52.2° N, 14.1° E). Both radars are separated by about 265 km. Based on wavelet transformations of both data sets, the dominant vertical wavelengths of about 2–4 km for fixed times as well as the dominant observed periods of about 11 h for the altitude range between 5 and 8 km are comparable. Gravity wave parameter have been estimated at both locations separately and by a complex cross-spectral analysis of the data of both radars. The results show the appearance of dominating inertia-gravity waves with characteristic horizontal wavelengths between 600 and 300 km moving in the opposite direction than the mean background wind and a secondary less pronounced wave with a horizontal wavelength in the order of about 200 km moving with the wind. Temporal and spatial differences of the observed waves are discussed.

scholarly journals Investigation of inertia-gravity waves in the upper troposphere/lower stratosphere over Northern Germany observed with collocated VHF/UHF radars

2005 ◽  
Vol 5 (2) ◽  
pp. 295-310 ◽  
Author(s):  
A. Serafimovich ◽  
P. Hoffmann ◽  
D. Peters ◽  
V. Lehmann
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Data Sets ◽  
Northern Germany ◽  
Vhf Radar ◽  
Upper Troposphere ◽  
Rossby Wave Breaking ◽  
Spatial Differences ◽  
Uhf Wind Profiler ◽  
Inertia Gravity Waves

Abstract. A case study to investigate the properties of inertia-gravity waves in the upper troposphere/lower stratosphere has been carried out over Northern Germany during the occurrence of an upper tropospheric jet in connection with a poleward Rossby wave breaking event from 17-19 December 1999. The investigations are based on the evaluation of continuous radar measurements with the OSWIN VHF radar at Kühlungsborn (54.1 N, 11.8 E) and the 482 MHz UHF wind profiler at Lindenberg (52.2 N, 14.1 E). Both radars are separated by about 265 km. Based on wavelet transformations of both data sets, the dominant vertical wavelengths of about 2-4 km for fixed times as well as the dominant observed periods of about 11 h and weaker oscillations with periods of  6 h for the altitude range between 5 and 8 km are comparable. Gravity wave parameters have been estimated at both locations separately and by a complex cross-spectral analysis of the data of both radars. The results show the appearance of dominating inertia-gravity waves with characteristic horizontal wavelengths of  300 km moving in the opposite direction than the mean background wind and a secondary less pronounced wave with a horizontal wavelength in the order of about 200 km moving with the wind. Temporal and spatial differences of the observed waves are discussed.

scholarly journals Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 field experiment

2015 ◽  
Vol 15 (13) ◽  
pp. 7667-7684 ◽  
Author(s):  
Fuqing Zhang ◽  
Junhong Wei ◽  
Meng Zhang ◽  
K. P. Bowman ◽  
L. L. Pan ◽  
...  
Keyword(s):  
Power Law ◽  
Gravity Waves ◽  
Lower Stratosphere ◽  
Potential Temperature ◽  
Shear Instability ◽  
Aircraft Measurements ◽  
Upper Troposphere ◽  
Airborne Measurements ◽  
Wide Range

Abstract. This study analyzes in situ airborne measurements from the 2008 Stratosphere–Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS). The focus is on the second research flight (RF02), which took place on 21–22 April 2008. This was the first airborne mission dedicated to probing gravity waves associated with strong upper-tropospheric jet–front systems. Based on spectral and wavelet analyses of the in situ observations, along with a diagnosis of the polarization relationships, clear signals of mesoscale variations with wavelengths ~ 50–500 km are found in almost every segment of the 8 h flight, which took place mostly in the lower stratosphere. The aircraft sampled a wide range of background conditions including the region near the jet core, the jet exit and over the Rocky Mountains with clear evidence of vertically propagating gravity waves of along-track wavelength between 100 and 120 km. The power spectra of the horizontal velocity components and potential temperature for the scale approximately between ~ 8 and ~ 256 km display an approximate −5/3 power law in agreement with past studies on aircraft measurements, while the fluctuations roll over to a −3 power law for the scale approximately between ~ 0.5 and ~ 8 km (except when this part of the spectrum is activated, as recorded clearly by one of the flight segments). However, at least part of the high-frequency signals with sampled periods of ~ 20–~ 60 s and wavelengths of ~ 5–~ 15 km might be due to intrinsic observational errors in the aircraft measurements, even though the possibilities that these fluctuations may be due to other physical phenomena (e.g., nonlinear dynamics, shear instability and/or turbulence) cannot be completely ruled out.

scholarly journals Internal Inertia–Gravity Waves in the Tropical Lower Stratosphere Observed by the Arecibo Radar

1984 ◽  
Vol 41 (15) ◽  
pp. 2359-2367 ◽  
Author(s):  
Yasuyuki Maekawa ◽  
Shoichiro Fukao ◽  
Toru Sato ◽  
Susumu Kato ◽  
Ronald F. Woodman
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Internal Inertia ◽  
Inertia Gravity Waves

scholarly journals A Study of Multiple Tropopause Structures Caused by Inertia–Gravity Waves in the Antarctic

2015 ◽  
Vol 72 (5) ◽  
pp. 2109-2130 ◽  
Author(s):  
Ryosuke Shibuya ◽  
Kaoru Sato ◽  
Yoshihiro Tomikawa ◽  
Masaki Tsutsumi ◽  
Toru Sato
Keyword(s):  
Gravity Waves ◽  
General Circulation ◽  
Climate Models ◽  
Lower Stratosphere ◽  
Circulation Model ◽  
Cold Bias ◽  
Syowa Station ◽  
Dynamical Mechanism ◽  
The Antarctic ◽  
Inertia Gravity Waves

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.

scholarly journals Inertia-gravity waves in the troposphere and lower stratosphere associated with a jet stream exit region

1999 ◽  
Vol 17 (1) ◽  
pp. 115-121 ◽  
Author(s):  
L. Thomas ◽  
R. M. Worthington ◽  
A. J. McDonald
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Middle Atmosphere ◽  
Vertical Shear ◽  
Jet Stream ◽  
Mesoscale Meteorology ◽  
Perturbation Velocity ◽  
Waves And Tides ◽  
Radar Measurements ◽  
Inertia Gravity Waves

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)

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