Projections of Variation in precipitation extream values in Sabzevar by LARS-WG downscaling model during 2011-2030 to 2046-2065

facing mankind ( Ipcc,2008 ). Infact one of the important aspects of climate change is understanding its behavior To have an outlook on future projections of climate extremes part Changes in extreme climate events has significant effects which caused a it to become as the most important challenges icularly precipitation, the outputs derived from three coupled general circulation models (HadCM3, CNCM3, NCCCSM) contributing to the Fourth Assessment Report of the IPCCAR4, under A1B emission scenarios have been downscaled by LARS-WG during three period 2011-2030, 2046-2065 for Sabzevar, station. The extremes are described by seven indices based on precipitation including (PRCPTOT,R10mm, R20mm,R95p,R99p,RX1day,RX5day,SDII) Results show that averages of Rx5day and SDII during The period of 2011-2030 will be probably increase under A2 sceranario . Inddition , alarge fraction of total annual precipitation is progected to occure in The form of heavy and showery events in 95th and 99th percentile . Regarding to The resultso incroases of 95th and 99th indices means That The frequency of flash floode and its intencity will be increased during 2011-2030 . Howerer , the intencity of precipitation and SDII will be probably to decreabse during2046-2064.