NAME =  V.S. prasad  
ORGANIZATION =  DPRI, Kyoto University  
ADDRESS =  Research Center for Disaster Enivironment, DPRI, Kyoto University, Gokasho, Uji, Kyoto,Japan  
COUNTRY =  Japan  
PHONE =  09020427941  
FAX =  +81 774 38 4181  
E-MAIL =  prasadvs@gmail.com  
POSTER_ONLY =  no  
THEME =  T3  
DATE =  27-Jul-04-12:14:02  
ABSID = T3Vp27Jul04121402 
TITLE = Evolution and Progression Characteristics of Indian Summer Monsoon 
AUTHOR_1 = V.S. Prasad 
INSTITUTION_1 = on leave from National Center for Medium Range Weather Forecasting, Mausam Bhavan, Lodhi Road, New Delhi, India 
PRESENTER = AUTHOR_1 
AUTHOR_2 = Taiichi Hayashi 
INSTITUTION_2 = Disaster Preventive Research Institute,  Kyoto University, Gokasho, Uji, Kyoto,Japan 
ABSTRACT =  Indian summer monsoon is the principal rainy season for India and thus the commencement and the cessation of this season bears a great significance. The initiation of the cross equatorial flow off the Somalia coast of Africa during May in response to the heating over the South Asian continent marks the beginning of the summer monsoon evolution process over the Arabian sea. The onset of monsoon over the South Kerala  coast  is manifested as a consequence of significant changes of atmospheric circulation, cloudiness etc and evolves gradually over the Arabian Sea. Long term records of onset over Kerala suggest that  the event is more or less  regular and its normal onset date of arrival over kerla is 31st May  with standard deviation of about eight days. The recent studies with the large scale analyses of the summer monsoon over the Indian region ( Ramesh et al. 1996, Swati et al. 1999, Fatsullo and Webster 2003, Prasad and Hayashi 2004) suggest that  it is possible to  determine the onset of monsoon  objectively by using potential indicators. In this study the onset, progression and withdrawal of the Indian summer monsoon  was retrospectively studied using ERA-40 data for the period 1958-2001. In addition , the temporal evolution of OLR fields from NOAA  long term OLR data sets to determine the association of cloud cover with the onset of monsoon.