NAME =  Yasushi Fujiyoshi  
ORGANIZATION =  FRCGC/Hokakido University  
ADDRESS =  N19W8 Sapporo 060-0819  
COUNTRY =  JAPAN  
PHONE =  011-706-5491  
FAX =  011-706-5491  
E-MAIL =  fujiyo@lowtem.hokudai.ac.jp  
POSTER_ONLY =  no  
THEME =  T2  
DATE =  09-Aug-04-19:42:10  
ABSID = T2YF09Aug04194210 
TITLE = Cloud formation and fractionation of stable isotope of water within Aritficial Cloud Experimental System  
AUTHOR_1 = Y. Fujiyoshi 
INSTITUTION_1 = FRCGC/Hokkaido Univ. 
PRESENTER = AUTHOR_1 
AUTHOR_2 = S. Nakajima 
INSTITUTION_2 = Graduate School of Environmental Science, Hokkaido Univ. 
AUTHOR_3 = S. Yamagata 
INSTITUTION_3 = Department of Engineering, Hokkaido Univ. 
ABSTRACT = By making use of Artificial Cloud Experimental System (ACES) in a long vertical shaft (430 m) of an iron mine in Kamaishi, Iwate Prefecture, we have examined the fundamental processes related to the formation of cloud.  Two electric fans sucked air at the top of the shaft to produce updraft velocity ranging from 0.5 to 2 m/s.  We conducted basic measurements of air temperature profiles, updraft air velocity, size distribution of cloud droplets and aerosol particles, etc.  We were firstly able to detect the very stable layer near the cloud base.  Vertical profiles of air temperature above and below it showed moist adiabatic and dry adiabatic lapse rate, respectively.  There existed the maximum supersaturation of relative humidity in the layer whose depth was only a few tens meter.  The cloud-physical processes that occur in the layer decide the size distribution of cloud droplets, thus, microphysical and radiative properties of a cloud.  Recent improvements of experimental conditions allowed us to study the indirect effect of aerosol particles.  In addition to the studies of cloud physics, we measured the stable isotope of water vapor below cloud base and of cloud water at several levels of a cloud.  We were firstly able to confirm the Rayleigh distillation process with a closed system. The results of experiments are being used to verify our detailed micro-physical model and parameterization schemes.