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

Ramkumar, Geetha; Antonita, T. Maria; Kumar, Yogesh; Kumar, Harshbardhan; Rao, D. Narayana

doi:10.5194/angeo-24-2471-2006

Cited by 21 publications

(17 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Subsequently, the gravity wave potential energy profiles are averaged to obtain the seasonal mean profile. By employing this procedure Ramkumar et al (2006) reported that the mean potential energy of gravity waves generally vary between 8 and 30 J/kg in the stratosphere and goes to a maximum of 35 J/kg in the 50-60 km region. Over Gadanki, there were a total of 109 SABER temperature profiles in the 5°9 10°g rid for the winter of 2004-2005.…”

Section: Resultsmentioning

confidence: 97%

“…The data are obtained as a part of ISRO's 5 year long Middle Atmospheric Dynamics (MIDAS) campaign. The details of the MIDAS programme along with their objectives can be found in detail in Ramkumar et al (2006). Inter comparison of the estimated gravity wave potential energy height profiles is carried out between LIDAR and SABER.…”

Section: Lidar Observations Over Gadankimentioning

confidence: 99%

See 1 more Smart Citation

TIMED/SABER observations of global gravity wave climatology and their interannual variability from stratosphere to mesosphere lower thermosphere

John

Kumar

2012

Clim Dyn

View full text Add to dashboard Cite

The present study for the first time reports the global gravity wave activity in terms of their potential energy derived from TIMED/SABER observations right from the stratosphere to the mesosphere lower thermosphere (MLT) region. The potential energy profiles obtained from SABER temperature are validated by comparing them with ground based LIDAR observations over a low latitude site, Gadanki (13.5°N, 79.2°E). The stratospheric and mesospheric global maps of gravity wave energy showed pronounced maxima over high and polar latitudes of the winter hemisphere. The interannual variability of the stratospheric gravity wave activity exhibited prominent annual oscillation over mid-latitudes. The equatorial gravity wave activity exhibited quasi-biennial oscillation in the lower stratosphere and semi-annual oscillation in the upper stratosphere. The MLT region maps revealed summer hemispheric maxima over polar latitudes and secondary maxima over the equatorial region. The results are discussed in the light of present understanding of global gravity wave observations. The significance of the present study lies in emphasizing the importance of satellite measurements in elucidating gravity waves, which is envisaged to have profound impact on parameterizing these waves.

show abstract

Section: Resultsmentioning

confidence: 97%

Section: Lidar Observations Over Gadankimentioning

confidence: 99%

TIMED/SABER observations of global gravity wave climatology and their interannual variability from stratosphere to mesosphere lower thermosphere

John

Kumar

2012

Clim Dyn

View full text Add to dashboard Cite

show abstract

“…Owing to the importance of this enigmatic region during the past few decades, various ground-and space-based investigations have been carried out to improve the overall understanding of the physical, chemical and dynamical processes (e.g. Ramkumar et al 2006 and references therein). Many unresolved scientific issues related to the middle atmospheric region still exist; hence, the middle atmospheric dynamics has been a focus of increasing scientific interest.…”

Section: Introductionmentioning

confidence: 99%

Variability of mesopause temperature derived from two independent methods using meteor radar and its comparison with SABER and EOS MLS and a collocated multi-wavelength dayglow photometer over an equatorial station, Thumba (8.5° N, 76.5° E)

Das

Kumar

Das

et al. 2012

International Journal of Remote Sensing

View full text Add to dashboard Cite

Variability of mesopause temperature derived from two independent methods using meteor radar and its comparison with SABER and EOS MLS and a collocated multi-wavelength dayglow photometer over an equatorial station, Thumba (8.Two independent methods for deriving mesopause temperature using meteor radar installed at an equatorial station, Thumba (8.5 • N, 76.5 • E), are discussed in this article. This meteor radar-derived mesopause temperature is then compared with two different types of spaceborne measurement, namely (i) Sounding the Atmosphere using Broadband Emission Radiometry (SABER) and (ii) the Earth Observing System Microwave Limb Sounder (EOS MLS), and a collocated multiwavelength dayglow photometer (DGPM). The meteor radar-derived temperature is in fairly good agreement with all the three measurement techniques, with an uncertainty of ±10 • . This study focuses on a detailed evaluation and inter-comparison of mesopause temperature derived from different measurement techniques. An attempt is also made to compare the suitability of these observations to study planetary waves and other oscillation activities in the mesospheric region.

show abstract

“…The fortnightly RH-200 rocket launches at Thumba yielded wind velocity profiles in the height region 20-65 km using the chaff releases (Ramkumar et al, 2006). The launch schedule during February-April 2006 was designed in order to have composite 24-h local time coverage at a time resolution of four hours.…”

Section: Observations and Data Analysismentioning

confidence: 99%

First results from the CAWSES-India Tidal Campaign

Gurubaran¹,

Rao

Ramkumar

et al. 2008

Ann. Geophys.

Self Cite

View full text Add to dashboard Cite

Abstract. The first CAWSES-India Tidal Campaign was conducted by the Indian scientific community during MarchApril 2006. The objectives of this campaign were: (1) To determine the characteristics of tides in the troposphere and lower stratosphere (0-20 km) and mesosphere and lower thermosphere (MLT) region (80-100 km), (2) to explore and identify what lower atmospheric processes drive middle atmospheric tides in the Indian continental region and (3) to provide information on those short-term variabilities of MLT tides that are likely to have an impact on the ionospheric variabilities and contribute to the upper atmospheric weather. Data sets from experiments conducted at the three low latitude radar sites, namely, Trivandrum (8.5 • N, 76.9 • E), Tirunelveli (8.7 • N, 77.8 • E) and Gadanki (13.5 • N, 79.2 • E) and fortnightly rocket launches from Thumba were made use of in this study. An important observational finding reported in this work is that the radar observations at Tirunelveli/Trivandrum indicate the presence of 15-20 day modulation of diurnal tide activity at MLT heights during the February-March period. A similar variation in the OLR fields in the western Pacific (120-160 • longitude region) suggests a possible link between the observed tidal variabilities and the variations in the deep tropical convection through the nonmigrating tides it generates.

show abstract

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

Abstract: Abstract. Altitude profiles of temperature in the stratospheric and mesopheric region from lidar observations at NARL, Gadanki, India,

Cited by 21 publications

References 34 publications

TIMED/SABER observations of global gravity wave climatology and their interannual variability from stratosphere to mesosphere lower thermosphere

TIMED/SABER observations of global gravity wave climatology and their interannual variability from stratosphere to mesosphere lower thermosphere

Variability of mesopause temperature derived from two independent methods using meteor radar and its comparison with SABER and EOS MLS and a collocated multi-wavelength dayglow photometer over an equatorial station, Thumba (8.5° N, 76.5° E)

First results from the CAWSES-India Tidal Campaign

Contact Info

Product

Resources

About