Inertia‐gravity waves associated with the tropical easterly jet over the Indian subcontinent during the South West Monsoon Period

Sasi, M. N.; Ramkumar, Geetha; Deepa, V.; Murthy, B. V. Krishna

doi:10.1029/1999gl011216

Cited by 20 publications

(18 citation statements)

References 31 publications

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“…8(a). This is quite consistent with the results reported by Sasi et al, (2000) reported from the same location using MST radar observations. Note that Zhang et al, (2010) has also suggested that height region from 10 to 18 km is an important source region for gravity waves, especially at low and middle latitudes.…”

Section: Discussionsupporting

confidence: 95%

Inertia gravity wave characteristics and associated fluxes observed using five years of radiosonde measurements over a tropical station

Leena

Ratnam

Murthy³

2012

Journal of Atmospheric and Solar-Terrestrial Physics

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Section: Discussionsupporting

confidence: 95%

Inertia gravity wave characteristics and associated fluxes observed using five years of radiosonde measurements over a tropical station

Leena

Ratnam

Murthy³

2012

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Since the present study has been undertaken in the month of July, the observed inertia gravity wave could have been the result of jet stream and/or convection in the surrounding area. Some estimated wave parameters are listed in Table 1 which are found to have close agreements with earlier reports for the same site (Sasi et al, 2000;Niranjan and Ramkumar, 2008).…”

Section: Inertia Gravity Wave Oscillationsupporting

confidence: 74%

“…So the source of the observed inertia gravity waves cannot be clearly indentified. Sasi et al (2000) had similar observations and suggested that the easterly jet present during summer monsoon could be the source of IGW. The high-resolution numerical simulation, by Mahalov et al (2007) showed the generation of inertia gravity waves from the jet stream at the tropopause.…”

Section: Inertia Gravity Wave Oscillationsupporting

confidence: 62%

High resolution observations of turbulence in the troposphere and lower stratosphere over Gadanki

Dutta¹,

Kumar²,

Kumar³

et al. 2009

Ann. Geophys.

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Abstract. High resolution (150 m) wind measurements from 13-17 July 2004 by Mesosphere-Stratosphere-Troposphere (MST) radar and 15-16 July 2004 by Lower Atmospheric Wind Profiler (LAWP) have been used to study the time variation of turbulence intensity. Layers of higher turbulence are observed in the lower stratosphere on 15-16 July which give rise to mixing in the region. Enhancement in short-period gravity wave activity and turbulent layers are observed after 22:00 LT which could be due to a dry convection event that occurred at that time. The breakdown of the convectively generated high frequency waves seems to have given rise to the turbulence layers. Wind shear is found to be high above the easterly jet, but very poor correlation is observed between square of wind shear and turbulence parameters in the region. The heights of the turbulent layers in the lower stratosphere do not correlate with levels of minimum Richardson number. A monochromatic inertia gravity wave could be identified during 13-17 July 2004. A non-linear interaction between the waves of different scales as proposed by Hines (1992) might also be responsible for the breakdown and generation of turbulence layers.

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“…Thomas et al [1992] reported downward and upward phase progression of gravity waves above and below the jet stream respectively. Sasi et al [2000] and Guest et al [2000] suggested the jet stream as the source of the observed inertia‐gravity waves. So the jet stream has been identified to be the source of both short and long period waves.…”

Section: Introductionmentioning

confidence: 99%

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

Dutta

Tsuda

Kumar³

et al. 2008

J. Geophys. Res.

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[1] We have analyzed the seasonal variation of short-period (<2 h) gravity wave activity in the troposphere and lower stratosphere using the wind observations made with VHF radar at Gadanki (13.5°N, 79.2°E), India. Four years of high resolution ($3 min) wind data (2003)(2004)(2005)(2006) have been used to study variance and momentum flux of short-period gravity waves. Both horizontal and vertical variances show annual variation. Variances in the upper troposphere (12-16 km) and lower stratosphere (18-21 km) are found to maximize in the wet months of June-July-August coinciding with the peaks of outgoing longwave radiation (OLR) and the rain rate (surface and Tropical Rainfall Measuring Mission [TRMM] 2 km rainfall). An additional strong peak of variance is observed in the height ranges of 4-12 km during spring which corresponds to TRMM storm height maximum. The measurements suggest deep convective activity to be the main source of short period gravity waves. Variances in the UTLS region are found to correlate well with square of wind shear indicating possible in situ generation of the gravity waves. Topographic generation of short period gravity waves does not seem to be important for this site. An interannual variability is observed in the measured wave activity. Zonal momentum flux shows annual variation with westward preference in the wet season whereas the meridional flux does not indicate any clear variation.

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Inertia‐gravity waves associated with the tropical easterly jet over the Indian subcontinent during the South West Monsoon Period

Cited by 20 publications

References 31 publications

Inertia gravity wave characteristics and associated fluxes observed using five years of radiosonde measurements over a tropical station

Inertia gravity wave characteristics and associated fluxes observed using five years of radiosonde measurements over a tropical station

High resolution observations of turbulence in the troposphere and lower stratosphere over Gadanki

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

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