Calibration and Validation of an All-Sky Imager  

作　　者：HUO Juan LU Da-Ren 

机构地区：[1]Key Laboratory for Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

出　　处：《Atmospheric and Oceanic Science Letters》2009年第4期220-223,共4页大气和海洋科学快报（英文版）

基　　金：supported by the national natural science foundation of China (Grant Nos.40505006 and 40775026)

摘　　要：The automatic all-sky imager developed by the Institute of Atmospheric Physics,Chinese Academy of Sciences,provides all-sky visible images in the red,green,and blue channels.This paper presents three major cali-bration experiments of the all-sky imager,geometric an-gular calibration,optical calibration,and radiometric calibration,and then infers an algorithm to retrieve rela-tive radiance from the all-sky images.Field experiments show that the related coefficient between retrieved radi-ance and measured radiance is about 0.91.It is feasible to use the algorithm to retrieve radiance from images.The paper sets up a relationship between radiance and the im-age,which is useful for using the all-sky image in nu-merical-simulations that predict more meteorological pa-rameters.The automatic all-sky imager developed by the Institute of Atmospheric Physics, Chinese Academy of Sciences, provides all-sky visible images in the red, green, and blue channels. This paper presents three major calibration experiments of the all-sky imager, geometric angular calibration, optical calibration, and radiometric calibration, and then infers an algorithm to retrieve relative radiance from the all-sky images. Field experiments show that the related coefficient between retrieved radiance and measured radiance is about 0.91. It is feasible to use the algorithm to retrieve radiance from images. The paper sets up a relationship between radiance and the image, which is useful for using the all-sky image in numerical-simulations that predict more meteorological parameters.

关 键 词：ALL-SKY VISIBLE image RADIANCE CLOUD 

分 类 号：P401[天文地球—大气物理学与大气环境] TN911.73[天文地球—大气科学及气象学]