Lidar observations of gravity wave activity in the upper stratosphere over Toronto

Whiteway, J.; Carswell, A. I.

doi:10.1029/95jd00511

Cited by 86 publications

(110 citation statements)

References 35 publications

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“…Figure 5 presents the occurrence frequency of GWPED for the 30-40 km altitude range and the time period from November to March. The GWPED of the first Gaussian mode presented in Table 3 agrees with the mean values of Alexander et al (2011), Rauthe et al (2008), and the January values of Whiteway and Carswell (1995). None of the locations examined in those studies are close to a strong source of mountain waves.…”

Section: From 90supporting

confidence: 70%

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Long-term lidar observations of wintertime gravity wave activity over northern Sweden

2014

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Abstract. This paper presents an analysis of gravity wave activity over northern Sweden as deduced from 18 years of wintertime lidar measurements at Esrange (68 • N, 21 • E). Gravity wave potential energy density (GWPED) was used to characterize the strength of gravity waves in the altitude regions 30-40 km and 40-50 km. The obtained values exceed previous observations reported in the literature. This is suggested to be due to Esrange's location downwind of the Scandinavian mountain range and due to differences in the various methods that are currently used to retrieve gravity wave parameters. The analysis method restricted the identification of the dominating vertical wavelengths to a range from 2 to 13 km. No preference was found for any wavelength in this window. Monthly mean values of GW-PED show that most of the gravity waves' energy dissipates well below the stratopause and that higher altitude regions show only small dissipation rates of GWPED. Our analysis does not reproduce the previously reported negative trend in gravity wave activity over Esrange. The observed interannual variability of GWPED is connected to the occurrence of stratospheric warmings with generally lower wintertime mean GWPED during years with major stratospheric warmings. A bimodal GWPED occurrence frequency indicates that gravity wave activity at Esrange is affected by both ubiquitous wave sources and orographic forcing.

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Section: From 90supporting

confidence: 70%

“…They compare better to observations at mid-latitudes presented by Rauthe et al (2008) and Whiteway and Carswell (1995) rather than those at high latitudes in the Northern Hemisphere. The low values of Thurairajah et al (2010b, a) also result from a different approach to obtain GWPED.…”

Section: From 90mentioning

confidence: 55%

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

2014

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“…High-resolution measurements (for example VHF radars and lidars), numerous modeling and theoretical studies have reported that the convective force effectively generates shortperiod (<1 hour) gravity waves (Salby and Garcia 1987;Fritts and Rastogi 1995;Whiteway and Carswell 1995;Alexander and Holton 1997;Piani et al 2000). Although spanning only a small portion of the gravity wave spectrum, satellite observations could provide some information on a global scale, especially on the seasonal and latitudinal variations of gravity waves with large vertical and horizontal scales (Fetzer and Gille 1994;Wu and Waters 1996;Eckerman and Preusse 1999;Tsuda et al 2000;Ratnam et al 2004).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, radiosondes and rocket soundings have been widely used to characterize gravity waves, especially in the upper and lower stratosphere (Hirota 1984;Marsh et al 1991;Sato et al 1994;Tsuda et al 1994;Eckerman et al 1995;Whiteway and Carswell 1995;Shimizu and Tsuda 1997;Sato and Dunkerton 1997). In particular, high-resolution radiosonde profiles collected on a campaign basis were effectively used to study the detailed characteristics on different time scales along with seasonal and latitudinal variations, especially for inertiagravity waves (e.g., Tsuda et al 1994;Karoly et al 1996;Tsuda et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Gravity Wave Characteristics over the Equator Observed During the CPEA Campaign using Simultaneous Data from Multiple Stations

Ratnam

Tsuda

Shibagaki

et al. 2006

Journal of the Meteorological Society of Japan

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The vertical and temporal variations of inertia-gravity waves are studied by means of an intensive radiosonde campaign conducted from 10 April to 9 May, 2004 at five sites, including the Equatorial Atmosphere Radar (EAR) site at Koto Tabang (0.2 S, 100.32 E) in west Sumatra, Indonesia. The four other balloon sounding sites are located about 75-400 km away from EAR. Dominant gravity waves with periods of 2-3 days and vertical wavelengths of approximately 3-5 km showing clear downward phase propagation were detected, particularly in the upper troposphere and lower stratosphere (UTLS) region. The gravity wave energy is found to become the largest at an altitude of approximately 20 km, although the enhancement was not continuous, but intermittent. The wave activity was similar at all five sites, having only a slight phase shift, which suggests that the horizontal scale of the wave is larger than the distance between the sites. We have applied a correlative analysis to delineate the horizontal propagation characteristics of gravity waves, and estimated the horizontal wavelength ðl h Þ to be approximately 1,700 km propagating toward 30 south from the east from 26-30 April, 2004, which is further verified by hodograph analysis for individual profiles. From 10-14 April, 2004 and 5-9 May, 2004, l h and the direction of the propagation were found to be 2,700 km and 3,250 km, and 26 and 3 north from the east, respectively. The spatial and temporal variations in the convection, which is thought to be a major Corresponding author: Dr. M. Venkat Ratnam, Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan. E-mail: vratnam@rish.kyoto-u.ac.jp ( 2006 Meteorological Society of Japan source in the generation of gravity waves, is also studied using satellite data of outgoing long-wave radiation (OLR). We noticed clear eastward advection of large super cloud clusters (SCCs) from the Indian Ocean to the maritime continent, with occasional movement towards the observational sites. The source of the gravity waves is strongly related to this slowly eastward-advecting tropospheric convection, implying that the wave activity observed in the UTLS region was generated by far distant sources located west of the EAR. In addition, we present a case study in which large wave activity did not correspond to the particular cloud convection.

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“…There are specific case studies, e.g., [1][2][3][4][5][6][7]; there are climatologies to determine the seasonal dependence of gravity wave activity or their relation to the atmospheric background conditions [8][9][10][11][12][13][14][15][16][17][18][19]; and there are studies developing the methodology to retrieve gravity wave signatures, e.g., [20]. Recently, the output of the high-resolution analyses of the Integrated Forecast System of the ECMWF was compared with lidar measurements in the middle atmosphere, e.g., [21].…”

Section: Introductionmentioning

confidence: 99%

On the Interpretation of Gravity Wave Measurements by Ground-Based Lidars

Dörnbrack¹,

Gisinger²,

Kaifler³

2017

Atmosphere

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This paper asks the simple question: How can we interpret vertical time series of middle atmosphere gravity wave measurements by ground-based temperature lidars? Linear wave theory is used to show that the association of identified phase lines with quasi-monochromatic waves should be considered with great care. The ambient mean wind has a substantial effect on the inclination of the detected phase lines. The lack of knowledge about the wind might lead to a misinterpretation of the vertical propagation direction of the observed gravity waves. In particular, numerical simulations of three archetypal atmospheric mountain wave regimes show a sensitivity of virtual lidar observations on the position relative to the mountain and on the scale of the mountain.

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Lidar observations of gravity wave activity in the upper stratosphere over Toronto

Cited by 86 publications

References 35 publications

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

Gravity Wave Characteristics over the Equator Observed During the CPEA Campaign using Simultaneous Data from Multiple Stations

On the Interpretation of Gravity Wave Measurements by Ground-Based Lidars

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