Development of a Moon Photometer to Measure Aerosol Optical Thickness

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K00531
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: National Institute for Environmental Studies
• Principal Investigator: Uchiyama Akihiro 国立研究開発法人国立環境研究所, 地球環境研究センター, 特別研究員 (50354460)
• Co-Investigator(Kenkyū-buntansha): 小林 拓 山梨大学, 大学院総合研究部, 准教授 (20313786) ; 松永 恒雄 国立研究開発法人国立環境研究所, 衛星観測センター, 研究センター長 (70302966)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: エアロゾル / エアロゾルの月光観測 / 月の反射率

Outline of Final Research Achievements

The majority of aerosol data are obtained from daytime measurements, and there are few datasets available for studying nighttime aerosol characteristics. In order to estimate the aerosol optical depth (AOD) and the precipitable water vapor (PWV) during the nighttime using the moon as a light source, a skyradiometer POM-02 (Prede Ltd., Japan) was modified. The calibration constants for both the sun and the moon were successfully determined by using the Langley method. The ratio of the both constants is the reflectance of moon. Therefore, the reflectance of the moon could be determined to within an accuracy of 1% or less. In order to validate the estimates of the AOD and PWV, continuous measurements with POM-02 were conducted. The results were compared with the AOD and PWV obtained by independent methods. In the results, the AODs (PWVs) during the daytime and nighttime are presumed to have the same degree of precision and accuracy within the measurement uncertainty.

Free Research Field

大気物理学

Academic Significance and Societal Importance of the Research Achievements

開発した放射計を用いて今まで情報がほとんど無かった夜間のエアロゾルの光学的厚さを満月±10日の間測定できるようになった。これにより昼夜連続したエアロゾルの動態解析が進展する。更に、月の正確な反射率が決定できたことにより、衛星搭載の可視・近赤外域センサーの校正に月を利用することで校正精度を上げることが可能となった。校正精度が上がることで衛星プロダクトの精度が上がり、より正確な情報が衛星から得られる。