16 June 2003 Development of a quasi-real-time system for estimating the surface solar flux using GMS-5
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A quasi real time system for estimate of the surface solar flux is introduced. The system will start to be operated in this year, and provide the solar flux until tomorrow’s morning. The system uses 0.09-degree resolution products from the GMS-5 image data of CEReS, Chiba Univ. It also uses the six-hourly atmospheric objective analysis data from the Japan Meteorological Agency. The solar flux is estimated at each pixel. This system includes four steps to estimate the surface solar flux. (1) The first step discriminates cloud pixel from clear one. The adopted method is similar to ISCCP, in which the reference Tbb for discrimination is created by data before and after the target day. In this system, it is impossible to use tomorrow’s data, because real time operation is needed. Therefore historical data is used to create the reference. (2) Cloud pixel is analyzed using 11/12 micron split window methods and 6.7 micron channel. The methods determine that the pixel is water or ice cloud, and derives the optical thickness for ice cloud. (3) The optical thickness for water cloud is retrieved from the reflection method using visible channel with assumption of the effective radius. (4) Cloud optical thickness and atmospheric information is converted to the surface solar flux from the package RSTAR5B for radiation transfer calculation. The surface solar flux using typical pixels from 0.5-degree grid area had been already derived. A comparison of satellite derived solar flux and the surface observation shows fair result in clear sky days, and overestimate in cloudy days.
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Itaru Okada, Itaru Okada, Tamio Takamura, Tamio Takamura, Toshiro Inoue, Toshiro Inoue, Takashi Y. Nakajima, Takashi Y. Nakajima, } "Development of a quasi-real-time system for estimating the surface solar flux using GMS-5", Proc. SPIE 4895, Applications with Weather Satellites, (16 June 2003); doi: 10.1117/12.466705; https://doi.org/10.1117/12.466705

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