Japan Geoscience Union Meeting 2021

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A (Atmospheric and Hydrospheric Sciences ) » A-CG Complex & General

[A-CG36] Satellite Earth Environment Observation

Thu. Jun 3, 2021 5:15 PM - 6:30 PM Ch.06

convener:Riko Oki(Japan Aerospace Exploration Agency), Yoshiaki HONDA(Center for Environmental Remote Sensing, Chiba University), Yukari Takayabu(Atmosphere and Ocean Research Institute, the University of Tokyo), Tsuneo Matsunaga(Center for Global Environmental Research and Satellite Observation Center, National Institute for Environmental Studies)

5:15 PM - 6:30 PM

[ACG36-P10] Improvement of cloud mask algorithm of CALIPSO lidar

*Eiji Oikawa1, Hajime Okamoto1, Kaori Sato1 (1.Research Institute for Applied Mechanics, Kyushu University)

Keywords:CALIPSO, lidar, cloud

The cloud mask algorithm at 532 nm had been developed for the CALIPSO satellite lidar retrieval (Hagihara et al., 2010). In the cloud mask scheme, the threshold value of attenuated backscattering coefficient to discriminate between clouds and aerosols was set to the fixed value, 10-5.25 m-1sr-1. Clouds near cloud base tend to be undetected in this cloud mask scheme, because attenuated backscattering coefficient affected by the attenuation of the upper cloud layers becomes lower than the threshold value of clouds and aerosols. Therefore, the threshold value between clouds and aerosols changes depending on cloud and molecule attenuation in the new cloud mask scheme. In this study, we use the CALIPSO level 1b product version 4.1 and the effects of the CALIPSO lidar receiver’s transient response on attenuated backscattering coefficient are corrected using the transient response function (Lu et al., 2014, 2020). In the new cloud mask scheme, clouds near cloud base are detected more frequently and the low-level cloud fraction increases.