Deduction of temperature profile from MST radar observations of vertical wind

Revathy, K.; Nair, S. R. Prabhakaran; Murthy, B. V. Krisha

doi:10.1029/96gl00086

Cited by 41 publications

(50 citation statements)

References 5 publications

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“…These observations were carried out as part of the equatorial wave studies campaign (Sasi et al, 2003). The temperatures in the 3 to 22 km altitude range are derived from the vertical wind data of ∼2-h duration (from 20:00 IST-22:00 IST) following the method derived by Revathy et al (1996). The standard error of these measurements is 0.7 K at 7 km and 1.6 K at 20 km (Revathy et al, 1998).…”

Section: Datamentioning

confidence: 99%

Observational evidence for the generation of a 4-day oscillation in the low-latitude middle atmosphere associated with an anomalous stratospheric cooling

2007

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Abstract. Altitude profiles of temperature in the stratosphere and lower mesosphere over Gadanki (13.5 • N, 79.2 • E), based on lidar observations during the Equatorial Wave Study campaign (29 February-2 April 2000), showed an anomalous cooling of the stratosphere, lasting for about 4-5 days. Immediately following this stratospheric cooling, a prominent ∼4-day period oscillation is observed in the zonal, as well as meridional wind in the 30-50 km altitude region, obtained from simultaneous rocketsonde and balloon wind measurements. The amplitude of this wave is in the range of 5-15 ms −1 in this altitude region. The altitude profiles of phase of this 4-day oscillation show a constant phase with height indicating that the wave is not propagating vertically. The causative mechanism for the sudden cooling is investigated by examining the day-to-day variation in the total atmospheric column ozone. Zonal and meridional wind components of this oscillation are approximately in quadrature phase, with zonal wind leading the meridional wind. Strikingly, while the 4-day wave is clearly observable in the zonal and meridional winds, it is almost absent in the temperature.

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Section: Datamentioning

confidence: 99%

Observational evidence for the generation of a 4-day oscillation in the low-latitude middle atmosphere associated with an anomalous stratospheric cooling

2007

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“…As has already been attested (Ecklund et al, 1985;Röttger, 1985;Revathy et al, 1996), the spectral representation of these variations generally show a peak corresponding to B-V and enable an easy detection of this parameter.…”

Section: Introductionmentioning

confidence: 81%

“…9). From then, T profiles can be deduced as has already be demonstrated by Revathy et al (1996) and Mohan et al (2001).…”

Section: Temperature Retrieval With the Vertical Wind Variation Technmentioning

confidence: 99%

Temperature retrieval with VHF radar using combined techniques

Klaus¹

2008

Ann. Geophys.

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Abstract. The purpose of this study is to evaluate the practical contribution of a VHF radar to high time resolution automatic temperature profiling both for research and operational applications in the frame of an integrated system of ground-based remote-sensing instruments. Based on the most prominent results already mentioned about this instrumentation, different techniques, related to the temperature data retrieval, are experimentally tested and documented using the INSU/Meteo 45 MHz wind profiler operating at CNRM/Toulouse or during cooperative campaigns. In parallel to the self-sufficient Radio Acoustic Sounding System (RASS), other approaches, using the Brunt-Vaisala frequency measurements, allow an extension of height coverage up to the higher troposphere and the tropopause. As only temperature gradients can be measured by this way, complementary data from other instruments are desirable. This makes it particularly fitted to an integrated remote-sensing system operating from the ground combining wind profilers with GPS, radiometers, lidar ceilometers and sodars.

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“…The BruntVäisälä frequency can be characterized by a spectral peak at the Brunt-Väisälä frequency with a steep decrease on its high frequency side and a shallow decrease on the low frequency side (Rastogi, 1975;Röttger, 1980aRöttger, , 1980bEcklund et al, 1985). Making use of Röttger's (1984) method, Revathy et al (1996) had derived temperature from the observed radar vertical velocities by identifying the Brunt-Väisälä frequencies.…”

Section: Introductionmentioning

confidence: 99%

“…First, vertical velocities are collected continuously using the radar and are subjected to Fast Fourier Transform (FFT) analysis to obtain Brunt-Väisälä oscillations. From the measured BruntVäisälä oscillations, temperature profile is obtained from the radar observations following Revathy et al (1996). The various terms required for the retrieval of vertical profiles of humidity are the eddy dissipation rate, ε, the volume reflectivity, η, and the potential refractive index gradient, M .…”

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confidence: 99%

Estimation of temperature and humidity from MST radar observations

Mohan

Rao

et al. 2001

Ann. Geophys.

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Abstract.Retrieval of vertical profiles of temperature and humidity parameters using a VHF radar is described in this paper. For this, Indian MST radar located at Gadanki (13.5• N, 79.2 • E) has been operated in a special mode. First, vertical velocities are collected continuously using the radar and are subjected to Fast Fourier Transform (FFT) analysis to obtain Brunt-Väisälä oscillations. From the measured BruntVäisälä oscillations, temperature profile is obtained from the radar observations following Revathy et al. (1996). The various terms required for the retrieval of vertical profiles of humidity are the eddy dissipation rate, ε, the volume reflectivity, η, and the potential refractive index gradient, M . The eddy dissipation rate, ε, is calculated from the spectral width after removing the effects due to non-turbulence. The volume reflectivity, η, of the turbulence scattering is calculated using the signal-to-noise ratio as a function of height. The potential refractive index gradient, M , is evaluated using the measured Brunt-Väisälä oscillations, the eddy dissipation rate and the volume reflectivity, η. Vertical profiles of humidity are retrieved following Tsuda (1997) using the radar derived temperature as well as the balloon measured temperature and are compared with the humidity as measured by the radiosonde. The sign of the potential refractive index gradient, M , is taken from the simultaneous measurements of balloon soundings. The retrieved vertical profiles of temperature and humidity have been compared with the radiosonde data, which are released simultaneously with the radar observations at the radar site. A fairly good comparison is seen between the two measurements on some days and there are some discrepancies on some other days. The strengths and limitations in estimating the vertical profiles of temperature and humidity from the radar observations are discussed.

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Deduction of temperature profile from MST radar observations of vertical wind

Abstract: From the temporal spectra of vertical wind obtained from MST radar observations, the Brunt‐Vaisala frequency is identified. Altitude profile of temperature in troposphere and lower stratosphere is derived from the altitude profile of the Brunt‐Vaisala frequency thus obtained.

Cited by 41 publications

References 5 publications

Observational evidence for the generation of a 4-day oscillation in the low-latitude middle atmosphere associated with an anomalous stratospheric cooling

Observational evidence for the generation of a 4-day oscillation in the low-latitude middle atmosphere associated with an anomalous stratospheric cooling

Temperature retrieval with VHF radar using combined techniques

Estimation of temperature and humidity from MST radar observations

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