Spectral analysis of 10m resolution scalar velocity profiles in the stratosphere

Dewan, E. M.; Grossbard, Neil; Quesada, A. F.; Good, R. E.

doi:10.1029/gl011i001p00080

Cited by 109 publications

(63 citation statements)

References 10 publications

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“…Here the term "universal" refers to the spectral structure of wind and temperature fluctuations, especially the spectral slope in the high wavenumber region, and is nearly independent of height, season, and geographical location. Decades of observations by different ground-based and satellite-borne instruments (Dewan et al, 1984;Dewan and Good, 1986;Smith et al, 1987;Fritts and Chou, 1987;Fritts et al, 1988;Tsuda et al, 1989;Wilson et al, 1990;Senft et al, 1993;Eckermann, 1999) further confirmed the universality. These observations revealed that in the large wavenumber region, i.e., the spectral tail region, the spectrum has a nearly universal index of −3.…”

Section: Introductionmentioning

confidence: 56%

Vertical wavenumber spectra of three-dimensional winds revealed by radiosonde observations at midlatitude

et al. 2017

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Abstract. By applying 12-year (1998-2009) radiosonde data over a midlatitude station, we studied the vertical wavenumber spectra of three-dimensional wind fluctuations. The horizontal wind spectra in the lower stratosphere coincide well with the well-known "universal spectra", with mean spectral slopes of − 2.91 ± 0.09 and −2.99 ± 0.09 for the zonal and meridional wind spectra, respectively, while the mean slopes in the troposphere are −2.64 ± 0.07 and −2.70 ± 0.06, respectively, which are systematically less negative than the canonical slope of −3. In both the troposphere and lower stratosphere, the spectral amplitudes (slopes) of the horizontal wind spectra are larger (less negative) in winter, and they are larger (less negative) in the troposphere than in the lower stratosphere. Moreover, we present the first statistical results of vertical wind fluctuation spectra, which revealed a very shallow spectral structure, with mean slopes of −0.58 ± 0.06 and −0.23 ± 0.05 in the troposphere and lower stratosphere, respectively. Such a shallow vertical wind fluctuation spectrum is considerably robust. Different from the horizontal wind spectrum, the slopes of the vertical wind spectra in both the troposphere and lower stratosphere are less negative in summer. The height variation of vertical wind spectrum amplitude is also different from that of the horizontal wind spectrum, with a larger amplitude in the lower stratosphere. These evident differences between the horizontal and vertical wind spectra strongly suggest they should obey different spectral laws. Quantitative comparisons with various theoretical models show that no existing spectral theories can comprehensively explain the observed three-dimensional wind spectra, indicating that the spectral features of atmospheric fluctuations are far from fully understood.

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Section: Introductionmentioning

confidence: 56%

Vertical wavenumber spectra of three-dimensional winds revealed by radiosonde observations at midlatitude

et al. 2017

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“…In recent years, the Rayleigh lidar technique has emerged as an effective means to study the gravity wave activity in the middle atmosphere over the height range of 30-70 km Hauchecorne, 1981, 1991;Wilson et al, 1990a, b;Gardner et al, 1989;Whiteway and Carswell, 1995;McDonald et al, 1998;Sivakumar et al, 2006;Ramkumar et al, 2006;Antonita et al, 2007). Further techniques provided important results, including rocketsonde measurements (Dewan et al, 1984), balloon soundings (Fritts et al, 1988;Nastrom et al, 1997). Radiosonde measurements, supplying wind velocity and temperature data in the troposphere and lower stratosphere, provided important information on wave climatology, sources, and effects in the lower atmosphere (Allen and Vincent, 1995;Vincent et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…Even though the radar provides the information on both frequency and vertical wave number spectra, much of the current theoretical focus is on understanding the nature of the vertical wave number spectrum of gravity waves. A key finding of many experimental studies on wave number and frequency power spectra of atmospheric gravity wave motions was that their spectral characteristics are widely uniform in frequency and wave number, despite different generation sources, meteorological conditions, and locations of observations (VanZandt, 1982;Dewan et al, 1984;Tsuda et al, 1989). A number of different theories have been developed to explain these observations and thus predict essentially the same vertical wave number spectrum, independent of the varying background conditions (Dewan and Good, 1986;Smith et al, 1987;Weinstock, 1990;Hines, 1991;Zhu, 1994;Gardner, 1994).…”

Section: Introductionmentioning

confidence: 99%

Long-term MST radar observations of vertical wave number spectra of gravity waves in the tropical troposphere over Gadanki (13.5° N, 79.2° E): comparison with model spectra

Babu

Kumar

et al. 2008

Ann. Geophys.

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Abstract. The potential utility of Mesosphere-StratosphereTroposphere (MST) radar measurements of zonal, meridional and vertical winds for divulging the gravity wave vertical wave number spectra is discussed. The data collected during the years 1995-2004 are used to obtain the mean vertical wave number spectra of gravity wave kinetic energy in the tropical troposphere over Gadanki (13.5 • N, 79.2 • E). First, the climatology of 3-dimensional wind components is developed using ten years of radar observations, for the first time, over this latitude. This climatology brought out the salient features of background tropospheric winds over Gadanki. Further, using the second order polynomial fit as background, the day-to-day wind anomalies are estimated. These wind anomalies in the 4-14 km height regions are used to estimate the profiles of zonal, meridional and vertical kinetic energy per unit mass, which are then used to estimate the height profile of total kinetic energy. Finally, the height profiles of total kinetic energy are subjected to Fourier analysis to obtain the monthly mean vertical wave number spectra of gravity wave kinetic energy. The monthly mean vertical wave number spectra are then compared with a saturation spectrum predicted by gravity wave saturation theory. A slope of 5/3 is used for the model gravity wave spectrum estimation. In general, the agreement is good during all the months. However, it is noticed that the model spectrum overestimates the PSD at lower vertical wave numbers and underestimates it at higher vertical wave numbers, which is consistently observed during all the months. The observed discrepancies are Correspondence to: A. Narendra Babu (narendraalur@gmail.com) attributed to the differences in the slopes of theoretical and observed gravity wave spectra. The slopes of the observed vertical wave number spectra are estimated and compared with the model spectrum slope, which are in good agreement. The estimated slopes of the observed monthly vertical wave number spectra are in the range of −2 to −2.8. The significance of the present study lies in using the ten years of data to estimate the monthly mean vertical wave number spectra of gravity waves, which will find their application in representing the realistic gravity wave characteristics in atmospheric models.

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“…In particular, VanZandt [1982] and other observational studies [e.g., Dewan et al, 1984;Smith et al, 1987] suggested that the vertical wavenumber spectrum of horizontal wind fluctuations displayed a universal small-scale "tail" with a log-log slope between about -2.5 and -3 and an amplitude that is nearly independent of height. A number of competing theories have been proposed to explain the universal character of the spectra and the small-scale "saturated" tail in particular.…”

Section: Introductionmentioning

confidence: 99%

Simulation of large‐scale dynamics in the mesosphere and lower thermosphere with the Doppler‐spread parameterization of gravity waves: 1. Implementation and zonal mean climatologies

Akmaev¹

2001

J. Geophys. Res.

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Abstract. Small-scale gravity waves (GWs) originating in the lower atmosphere maintain the large-scale structure and circulation in the mesosphere and lower thermosphere (MLT). At solstice the drag imposed by these waves supports a strong meridional circulation from summer pole to winter pole that acts as a giant "refrigerator" transporting heat from a colder summer mesosphere to a warmer winter mesosphere.

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Spectral analysis of 10m resolution scalar velocity profiles in the stratosphere

Cited by 109 publications

References 10 publications

Vertical wavenumber spectra of three-dimensional winds revealed by radiosonde observations at midlatitude

Vertical wavenumber spectra of three-dimensional winds revealed by radiosonde observations at midlatitude

Long-term MST radar observations of vertical wave number spectra of gravity waves in the tropical troposphere over Gadanki (13.5° N, 79.2° E): comparison with model spectra

Simulation of large‐scale dynamics in the mesosphere and lower thermosphere with the Doppler‐spread parameterization of gravity waves: 1. Implementation and zonal mean climatologies

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