Observation of particle fall velocity in cirriform cloud by VHF and millimeter-wave Doppler radars

Masayuki K. Yamamoto, Yuichi Ohno, Hiroaki Horie, Noriyuki Nishi, Hajime Okamoto, Kaori Sato, Hiroshi Kumagai, Mamoru Yamamoto, Hiroyuki Hashiguchi, Shuichi Mori, Noriko O. Hashiguchi, Hajime Nagata, Shoichiro Fukao

研究成果: ジャーナルへの寄稿記事

8 引用 (Scopus)

抄録

In this study, it is demonstrated that a combination of VHF and millimeter-wave Doppler radars is a key tool for observing particle fall velocity in cirriform clouds. VHF (47-MHz) and millimeter-wave (95-GHz) Doppler radars observed cirriform clouds at West Sumatra, Indonesia (0.2°S, 100.32°E) from 2000 LT 14 to 0800 LT 15 November 2005. Radar reflectivity factor (Ze) observed by the 95-GHz radar showed that echoes from cloud particles had tops around 12-14 km and bottoms around 8-10 km. Doppler velocity observed by the vertically pointed beam of the 95-GHz radar (Vair+Z) was compared with vertical air velocity (Vair) observed by the 47-MHz radar to confirm that Vair+Z, a sum of Vair and reflectivity-weighted particle fall velocity (VZ), showed consistent changes with Vair and hence VZ is able to be retrieved by subtracting Vair from Vair+Z. The correlation coefficient between VZ and Ze in the middle part of clouds (10.5-12.2 km) was -0.81, which was higher than that (-0.47) in the bottom part (7.2-10.5 km). The change of VZ for Ze in the middle part was larger (Ze = -31.9 VZ - 32.2) than that in the bottom part (Ze, = -90.2 VZ - 71.8). These results suggest that particle size was a dominant factor that determined Ze in the middle part. Using VZ, median volume diameter (D0) was estimated to suggest that D0 was larger than ∼70 μm in the bottom part and ranged from ∼40 μm to larger than ∼106 μm in the middle part.

元の言語英語
記事番号D12210
ジャーナルJournal of Geophysical Research Atmospheres
113
発行部数12
DOI
出版物ステータス出版済み - 6 27 2008

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Millimeter waves
millimeter waves
radar
air
Air
Radar
reflectivity
Indonesia
particle
reflectance
correlation coefficients
particle size
echoes
Particle size

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

これを引用

Observation of particle fall velocity in cirriform cloud by VHF and millimeter-wave Doppler radars. / Yamamoto, Masayuki K.; Ohno, Yuichi; Horie, Hiroaki; Nishi, Noriyuki; Okamoto, Hajime; Sato, Kaori; Kumagai, Hiroshi; Yamamoto, Mamoru; Hashiguchi, Hiroyuki; Mori, Shuichi; Hashiguchi, Noriko O.; Nagata, Hajime; Fukao, Shoichiro.

:: Journal of Geophysical Research Atmospheres, 巻 113, 番号 12, D12210, 27.06.2008.

研究成果: ジャーナルへの寄稿記事

Yamamoto, MK, Ohno, Y, Horie, H, Nishi, N, Okamoto, H, Sato, K, Kumagai, H, Yamamoto, M, Hashiguchi, H, Mori, S, Hashiguchi, NO, Nagata, H & Fukao, S 2008, 'Observation of particle fall velocity in cirriform cloud by VHF and millimeter-wave Doppler radars', Journal of Geophysical Research Atmospheres, 巻. 113, 番号 12, D12210. https://doi.org/10.1029/2007JD009125
Yamamoto, Masayuki K. ; Ohno, Yuichi ; Horie, Hiroaki ; Nishi, Noriyuki ; Okamoto, Hajime ; Sato, Kaori ; Kumagai, Hiroshi ; Yamamoto, Mamoru ; Hashiguchi, Hiroyuki ; Mori, Shuichi ; Hashiguchi, Noriko O. ; Nagata, Hajime ; Fukao, Shoichiro. / Observation of particle fall velocity in cirriform cloud by VHF and millimeter-wave Doppler radars. :: Journal of Geophysical Research Atmospheres. 2008 ; 巻 113, 番号 12.
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title = "Observation of particle fall velocity in cirriform cloud by VHF and millimeter-wave Doppler radars",
abstract = "In this study, it is demonstrated that a combination of VHF and millimeter-wave Doppler radars is a key tool for observing particle fall velocity in cirriform clouds. VHF (47-MHz) and millimeter-wave (95-GHz) Doppler radars observed cirriform clouds at West Sumatra, Indonesia (0.2°S, 100.32°E) from 2000 LT 14 to 0800 LT 15 November 2005. Radar reflectivity factor (Ze) observed by the 95-GHz radar showed that echoes from cloud particles had tops around 12-14 km and bottoms around 8-10 km. Doppler velocity observed by the vertically pointed beam of the 95-GHz radar (Vair+Z) was compared with vertical air velocity (Vair) observed by the 47-MHz radar to confirm that Vair+Z, a sum of Vair and reflectivity-weighted particle fall velocity (VZ), showed consistent changes with Vair and hence VZ is able to be retrieved by subtracting Vair from Vair+Z. The correlation coefficient between VZ and Ze in the middle part of clouds (10.5-12.2 km) was -0.81, which was higher than that (-0.47) in the bottom part (7.2-10.5 km). The change of VZ for Ze in the middle part was larger (Ze = -31.9 VZ - 32.2) than that in the bottom part (Ze, = -90.2 VZ - 71.8). These results suggest that particle size was a dominant factor that determined Ze in the middle part. Using VZ, median volume diameter (D0) was estimated to suggest that D0 was larger than ∼70 μm in the bottom part and ranged from ∼40 μm to larger than ∼106 μm in the middle part.",
author = "Yamamoto, {Masayuki K.} and Yuichi Ohno and Hiroaki Horie and Noriyuki Nishi and Hajime Okamoto and Kaori Sato and Hiroshi Kumagai and Mamoru Yamamoto and Hiroyuki Hashiguchi and Shuichi Mori and Hashiguchi, {Noriko O.} and Hajime Nagata and Shoichiro Fukao",
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AU - Yamamoto, Masayuki K.

AU - Ohno, Yuichi

AU - Horie, Hiroaki

AU - Nishi, Noriyuki

AU - Okamoto, Hajime

AU - Sato, Kaori

AU - Kumagai, Hiroshi

AU - Yamamoto, Mamoru

AU - Hashiguchi, Hiroyuki

AU - Mori, Shuichi

AU - Hashiguchi, Noriko O.

AU - Nagata, Hajime

AU - Fukao, Shoichiro

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