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AGU: Journal of Geophysical Research, Atmospheres

 

Keywords

  • clouds
  • radar
  • lidar

Index Terms

  • Atmospheric Composition and Structure: Cloud physics and chemistry
  • Atmospheric Composition and Structure: Cloud/radiation interaction
  • Atmospheric Composition and Structure: Aerosols and particles
  • Atmospheric Composition and Structure: Radiation: transmission and scattering
Abstract
Cited By (5)
 

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, D24213, 17 PP., 2008
doi:10.1029/2008JD009812

Vertical cloud properties in the tropical western Pacific Ocean: Validation of the CCSR/NIES/FRCGC GCM by shipborne radar and lidar

Hajime Okamoto

Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Sendai, Japan

Tomoaki Nishizawa

National Institute for Environmental Studies, Tsukuba, Japan

Toshihiko Takemura

Research Institute for Applied Mechanics, Kyushu University, Kasuga, Japan

Kaori Sato

Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Sendai, Japan

Hiroshi Kumagai

National Institute of Information and Communications Technology, Koganei, Japan

Yuichi Ohno

National Institute of Information and Communications Technology, Koganei, Japan

Nobuo Sugimoto

National Institute for Environmental Studies, Tsukuba, Japan

Atsushi Shimizu

National Institute for Environmental Studies, Tsukuba, Japan

Ichiro Matsui

National Institute for Environmental Studies, Tsukuba, Japan

Teruyuki Nakajima

Center for Climate System Research, University of Tokyo, Kashiwa, Japan

This study examined the vertical cloud structure over the tropical western Pacific Ocean using 95-GHz radar and lidar data observed from September to December 2001 during the MR01-K05 cruise of the research vessel Mirai. The cloud vertical structure was homogeneous between 6 and 10 km, and the maximum cloud occurrence was 20% and located at 12 km. The mean precipitation occurrence was 11.5% at 1 km. The cloud fraction, radar reflectivity factor, and lidar backscattering coefficient were simulated along the Mirai cruise track using the output from the Center for Climate System Research, University of Tokyo; National Institute for Environmental Studies; and Frontier Research Center for Global Change (CCSR/NIES/FRCGC) general circulation model (GCM). The original output showed the maximum cloud fraction at 15 km; however, after considering attenuation and the minimum sensitivity of the radar, the maximum shifted to 12 km. The model overestimated the cloud fraction above 8 km, with the simulated fraction more than twice as large as the observed fraction. The model overpredicted the frequency of deep convection reaching the upper atmosphere above 12 km. Further, it overestimated precipitation frequency. Simulated radar reflectivity was underestimated throughout the entire altitude range, whereas simulated and observed lidar backscattering were in good agreement above 12 km with subgrid-scale treatment. The ice effective radius of 40 μm and ice water content were reasonable in thin clouds, but the radius was underestimated in other regions. The simulated liquid water content was overestimated.

Received 11 January 2008; accepted 9 October 2008; published 31 December 2008.

Citation: Okamoto, H., T. Nishizawa, T. Takemura, K. Sato, H. Kumagai, Y. Ohno, N. Sugimoto, A. Shimizu, I. Matsui, and T. Nakajima (2008), Vertical cloud properties in the tropical western Pacific Ocean: Validation of the CCSR/NIES/FRCGC GCM by shipborne radar and lidar, J. Geophys. Res., 113, D24213, doi:10.1029/2008JD009812.

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