Abstract：Beijing weather observatory is the first test station to install new automatic observation instrument.This paper takes a comparison on the 24 hours visibility data obtained by manual observation and new instrument measurement with 0-35km range in August,2013.The correlation and the deviation size between the visibility data measured by machine and manual are analyzed in the different ranges between 0 to 2 km,2 to 5km,5 to 10km,10 to 20km,and 20 to 35km during different periods of day and night.The comparative results show that the correlation and deviation of the low visibility is better than high visibility.The day is better than the night.And the reasons caused that have been analyzed briefly in this paper.
2014, Vol. 31 
