Title: ACE-Asia Surface: Kosan METRI Sunphotometer data Summary: This file is an explanatory note about 'METRI_Sunphoto.txt' file. File format: TXT file The result express a spectral optical depth applied cloud screening algorithm from Sunphotometer (Smirnov et al., 2000; Min et al. , 2002) Data Category: Surface Network/Source: Kosan, Jeju Observing Frequency: every one minutes Begin Date: 1 March 2001 End Date: 6 May 2001 Region: ACE-Asia Latitude: 33o 17' N Longitude: 126o 10' E P. I.: Byoung-Cheol Choi and Jiyoung Kim Questions about the data should be directed to: jykim@metri.re.kr Each column is as follows. Column No. Elements Units Comments 1 Julian day 2 time 3 solar zenith angle (degree) 4 airmass 5 aerosol optical depth (368nm) 6 aerosol optical depth (500nm) 7 aerosol optical depth (675nm) 8 aerosol optical depth (778nm) 9 aerosol optical depth (862nm) 10 Angstrom Exponent 11 Angstrom Turbidity 12 Visibitity (Km) ( Iqbal, 1983 ) 13 number of data number of selected data in a day after applied cloud sceening algorithm reference Smirnov et al., 2000: Cloud screening and quality control algorithms for the AERONET database, Rem.Sens.Environ. Min et al., 2002: Characteristics of spectral aerosol optical depth retrieved from ground-based Sunphotometer measurements in Seoul, Korea : An application of cloud screening algorithm (CSA), J. Korean Meteor. Soc., 38(1), 25-38. Iqbal, 1983: An Introduction to solar Radiation, Academic Press,107-168pp.