Abstract: The responses of diurnal temperature difference,summer days and frost days during 2071-2100(2080s) under SRES A2 and B2 scenarios in Ningxia was analyzed by using the PRECIS(Providing Regional Climate for Impacts Studies),a regional climate model system developed by the UK Met Office Hadley Center for Climate Prediction and Research.ECMWF 1979-1993 reanalysis data(ERA15) was used as quasi-observational boundary condition to drive the PRECIS.Through comparison of the simulated diurnal temperature difference,summer days and frost days and in situ observation in meteorological stations,the results showed that PRECIS might reproduce spatial distribution and annual variation of these extreme indexes in Ningxia,but diurnal temperature difference and the summer days were over-estimated,and the frost days was under-estimated in south of Ningxia.According to comparison of the simulated baseline(1961-1990) frequency and observation,it indicated that PRECIS might simulate frequency distribution of these extreme climate indexes.Meanwhile,observation data was used to correct simulated data,the corrected simulation matched the observation data was better than the un-corrected.Diurnal temperature difference would decrease in Ningxia during 2080s to baseline under SRES A2 and B2 scenarios.The summer days would increase remarkably and the increment would reach 69 days and 48 days per year.On the contrary,the frost days would decrease and the decrement could reach 50 days and 36 days per year respectively under two scenarios.

Key words: PRECIS, PRECIS, Diurnal temperature difference, Summer days, Frost days, SRES A2, B2 scenarios