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-bratio...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.展开更多
In her trademark style,Xinran’s latest book,China Witness:Voices from a Silent Generation,weaves previously untold stories from China.This time, the stories are about grandparents and great-grandparents who were witn...In her trademark style,Xinran’s latest book,China Witness:Voices from a Silent Generation,weaves previously untold stories from China.This time, the stories are about grandparents and great-grandparents who were witnesses to unprecedented changes—including war, famine,invasion and Westernization—in this country over the last century.展开更多
基金supported by the national natural science foundation of China (Grant Nos.40505006 and 40775026)
文摘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.
文摘In her trademark style,Xinran’s latest book,China Witness:Voices from a Silent Generation,weaves previously untold stories from China.This time, the stories are about grandparents and great-grandparents who were witnesses to unprecedented changes—including war, famine,invasion and Westernization—in this country over the last century.
