Fukao, Shoichiro

Hashiguchi, Hiroyuki

Yamamoto, Masayuki K.

Kyoto University Research Information Repository

TitleCirrus cloud observation in the tropical upper troposphere bythe Equatorial Atmosphere Radar (EAR) and 95-GHz cloudradar(RECENT RESEARCH ACTIVITIES)Author(s)Fukao, Shoichiro; Hashiguchi, Hiroyuki; Yamamoto, MasayukiK.CitationSustainable humanosphere : bulletin of Research Institute forSustainable Humanosphere Kyoto University (2006), 2: 7-7Issue Date2006-08-31URL http://hdl.handle.net/2433/51088RightType Departmental Bulletin PaperTextversionpublisherKyoto UniversityRECENT RESEARCH ACTIVITIESCirrus cloud observation in the tropical upper troposphere by the EquatorialAtmosphere Radar (EAR) and 95-GHz cloud radar(Laboratory for radar atmospheric sciences, RISH, Kyoto University)Shoichiro Fukao, Hiroyuki Hashiguchi, and Masayuki K. YamamotoCirrus clouds are high- and thin-tropospheric clouds composed predominately of ice particles. Tropicalcirrus clouds cover a significant part of the tropics and have a key effect on the Earth's radiation budget.They occupy an area much greater than the deep convection that produces them. Modeling andobservational studies have been carried out to understand the complete life cycle of tropical cirrus cloudsand basic processes responsible for their persistence. However, observational studies on the interactionsamong radiation, dynamics, and microphysics remain too sparse. Especially, dynamical processes oftropical cirrus clouds are not understood well, because wind observation in and around tropical cirrusclouds with high temporal and vertical resolution has not been carried out.A VHF-band wind profiler called the Equatorial Atmosphere Radar (EAR) can observe winds in bothclear and cloudy regions by receiving echoes from atmospheric turbulence [1]. A 95-G Hz cloud radar candetect ice particles within cirrus clouds due to its short wavelength (3.2 mm) [2]. Therefore, thecombination of the EAR and the 95-GHz cloud radar enables us to observe fine wind structure in andaround cirrus clouds. In November 2005, our research group has carried out the observation campaignusing the EAR and 95-GHz cloud radar to understand how background wind affects dynamical andmicrophysical processes of cirrus clouds. The observation campaign was carried out as a joint project byRISH and National Institute of Information and Communications Technology (NICT). The 95-MHz cloudradar is installed close to the EAR at the Equatorial Atmosphere Observatory (0.2S, 100.32E, 865 m abovesea level) near Bukittinggi, West Sumatra, Indonesia.From the preliminary data analysis, our research group has already obtained several new findings: alinkage between falling velocity of ice particles and background vertical air motion, enhanced turbulencenear the cloud bottom caused by evaporative cooling, and so on. Other than the EAR and the 95-GHz cloudradar, many instruments such as weather radars, lidar, and radiosondes were under operation during theobservation campaign. Using these data, the dynamical and microphysical processes of tropical cirrusclouds will be further investigated.Figure 2: A view of the EARFigure 1: Picture of the95-GHz cloud radarREFERENCES[1] Fukao, S., Hashiguchi, H., Yamamoto, M., Tsuda, T., Nakamura T., Yamamoto M. K., Sato, T., Hagio,M., and Yabugaki. Y. (2003), Radio Sci., 38(3),1053, doi:l0.l029/2002RS002767.[2] Horie, H., T. Iguchi, H. Hanado, H. Kuroiwa, H. Okamoto, H. Kumagai (2000), IEICE TRANS.COMMUN., 83,2010-2020.7

Cirrus cloud observation in the tropical upper troposphere by the Equatorial Atmosphere Radar (EAR) and 95-GHz cloud radar(RECENT RESEARCH ACTIVITIES)

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Cirrus cloud observation in the tropical upper troposphere by the Equatorial Atmosphere Radar (EAR) and 95-GHz cloud radar(RECENT RESEARCH ACTIVITIES)

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