Dust Devil–Like Vortices in an Urban Area Detected by a 3D Scanning Doppler Lidar

Fujiwara, Chusei; Yamashita, Kazuya; Nakanishi, Mikio; Fujiyoshi, Yasushi

doi:10.1175/2010jamc2481.1

Cited by 31 publications

(24 citation statements)

References 28 publications

(31 reference statements)

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“…From August 2009 to March 2011, we conducted WINPOD-L (WINd Power Observation by Doppler-Lidar) field project ) to measure the offshore wind power at Ikeshima island, Nagasaki Prefecture (32.8825°N, 129.5910°E) using our 3D-CDL instrument (Fujiyoshi et al 2006;Fujiwara et al 2011). Figure 1 shows a topographic map of the observation area and the detection range of the 3D-CDL installed on the roof of an incinerator (75 m above sea level (ASL)).…”

Section: Observational Setting Of the 3d-cdl And Cdr Datasetmentioning

confidence: 99%

“…Using the method presented by Suzuki et al (2008), we attempted to detect vortices in a PPI scan of the 3D-CDL (see Fujiwara et al (2011) for details). The distance between the maximum and minimum Doppler velocities (D) was defined as the "deduced core diameter" of each vortex, and the deduced vertical vorticity (ζ ) and peak tangential velocity were estimated as 2ΔV/D and ΔV/2, respectively, where ΔV is the difference in the Doppler velocities of the receding and approaching extrema in the vortex signature.…”

Section: Observational Setting Of the 3d-cdl And Cdr Datasetmentioning

confidence: 99%

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Detection of “Invisible Waterspout” Using 3D Scanning Doppler Lidar

Fujiwara¹,

Fujiyoshi

2014

SOLA

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A three-dimensional coherent Doppler lidar (3D-CDL) and an interval camera were used to detect a cyclonic "invisible waterspout" very close to the sea surface near Ikeshima island, Nagasaki Prefecture, on 21 December 2010. High-resolution 3D-CDL images revealed that the waterspout had a subscale vortex. The deduced core diameter of the waterspout (subscale vortex) was 234 m (105 m), and the vorticity was 0.17 s −1 (0.32 s −1). The estimated maximum wind speed of the waterspout was about 17 m s, which falls into the category of an F0-scale tornado. Analysis of the 3D-CDL and C-band Doppler radar data shows that the waterspout and two vortices were observed along a gust front ahead of the parent storm.(Citation: Fujiwara, C., and Y. Fujiyoshi, 2014: Detection of "invisible waterspout" using 3D scanning Doppler lidar. SOLA, 10, 127−130,

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Section: Observational Setting Of the 3d-cdl And Cdr Datasetmentioning

confidence: 99%

Section: Observational Setting Of the 3d-cdl And Cdr Datasetmentioning

confidence: 99%

Detection of “Invisible Waterspout” Using 3D Scanning Doppler Lidar

Fujiwara¹,

Fujiyoshi

2014

SOLA

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“…1c) . From a RHI scan taken by the 3D-CDL, the height of ABL (z i ) was determined by locating the height of the maximum negative gradient in its profile (Fujiwara et al 2011).…”

Section: Observational Setting Of the 3d-cdl And Detection Of Dust Dementioning

confidence: 99%

“…Using a three-dimensional scanning coherent Doppler lidar (3D-CDL), we detected many dust devil-like vortices in Sapporo, an urban area, from April 2005 to July 2007 (Fujiwara et al 2011). A total of 50 strong vortices were detected over a total of 7 days during the period of observation.…”

Section: Introductionmentioning

confidence: 99%

Observed Effect of Mesoscale Vertical Vorticity on Rotation Sense of Dust Devil-Like Vortices in an Urban Area

Fujiwara¹,

Yamashita

Fujiyoshi

2012

SOLA

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Dust devil-like vortices were detected by a three-dimensional scanning coherent Doppler lidar (3D-CDL) in an urban area of Sapporo, Japan, from April 2005 to July 2007. A total of 57 strong, dust devil-like vortices with vertical vorticity exceeding 0.1 s −1 were detected in 8 days of the observation period and were associated with a convective cell (fish net) pattern of wind fields detected by the 3D-CDL. The observed vortices had both rotation senses for 7 days. However, all of 7 dust devil-like vortices were cyclonic on 4 October 2006 when cyclonic mesoscale circulation with 4.5 × 10 −4 s −1 in vertical vorticity existed over the 3D-CDL observation area. This result is the observed evidence that mesoscale circulation affects rotation sense of vortices.

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“…In situ observations have used anemometers to measure wind speed in dust devils (e.g Kaimal and Businger 1970). Remote sensing by a Doppler radar (Bluestein et al 2004) and Doppler lidar (Fujiwara et al 2011) also measured wind speeds in dust devils and even invisible dust devil-like vortices, respectively.On the other hand, an increasing number of numerical studies have been presented recently. However, most numerical studies suffer from underestimates of wind speeds even if very high resolution is used (e.g.…”

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confidence: 99%

Particle Image Velocimetry of a Dust Devil Observed in a Desert

Ito

Niino

2014

SOLA

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Dust devils are small-scale atmospheric vortices that are often observed on deserts. Using a video of a dust devil that occurred in a close distance, this study attempts to apply Particle Image Velocimetry (PIV) to obtain flows in the dust devil for the first time. Images taken by two cameras enable us to connect a pixel size into actual length scale. The estimated maximum tangential wind and updraft in the dust devil are 16 m s −1 and 6 m s −1, respectively. These wind speeds are comparable to these of strong ones reported in previous observational studies.(Citation: Ito, J., and H. Niino, 2014: Particle image velocimetry of a dust devil observed in a desert. SOLA, 10, 108−111, doi:10.2151/sola.2014-022.) IntroductionDust devils are atmospheric vertical vortices that often appear on deserts or bare land during daytime in a fine day. Dust particles lifted by strong winds and updrafts in the vortices visualize themselves. Gusty winds associated with them often prevent outdoor activities, and occasionally cause damage to weak structures such as tents and resulting injuries.Several field observations were made to measure winds and pressure depression of dust devils both on the Earth and Mars (e.g Balme and Greeley 2006). In situ observations have used anemometers to measure wind speed in dust devils (e.g Kaimal and Businger 1970). Remote sensing by a Doppler radar (Bluestein et al. 2004) and Doppler lidar (Fujiwara et al. 2011) also measured wind speeds in dust devils and even invisible dust devil-like vortices, respectively.On the other hand, an increasing number of numerical studies have been presented recently. However, most numerical studies suffer from underestimates of wind speeds even if very high resolution is used (e.g. Kanak 2005;Raasch and Franke 2011;Ito et al. 2013). The reason for the underestimate is still uncertain, and further observations of the wind speeds and turbulence characteristics in dust devils are desired.Observations by cameras along with image processing may be a useful method to systematically investigate a number of dust devils. Stanzel et al. (2006Stanzel et al. ( , 2008 have obtained translational speeds of dust devils on the Mars. Balme et al. (2012) implies correlations between translational speeds of dust devils and ambient winds based on terrestrial field observations. Thus, prevailing wind speeds on the Mars may be estimated from a translational motion of a dust devil. These studies, however, did not focus on the flows in dust devils.Particle Image Velocimetry (PIV) is a method which looks for the best matching of distributions of pixel patterns in two successive frames to obtain two-dimensional velocities (e.g. Raffel et al. 1998). In a video of a dust devil (Supplemental movie S1) which is taken by the first author (JI) with consumer cameras, one may perceive its counter-clockwise rotation and upward motions in the vortex. If PIV is applied to the video, some characteristics of the flows in the dust devil may be retrieved. Thanks to the recent progress and widespread ...

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Dust Devil–Like Vortices in an Urban Area Detected by a 3D Scanning Doppler Lidar

Cited by 31 publications

References 28 publications

Detection of “Invisible Waterspout” Using 3D Scanning Doppler Lidar

Detection of “Invisible Waterspout” Using 3D Scanning Doppler Lidar

Observed Effect of Mesoscale Vertical Vorticity on Rotation Sense of Dust Devil-Like Vortices in an Urban Area

Particle Image Velocimetry of a Dust Devil Observed in a Desert

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