Statistical modelling and projection of winter extreme cold spells over South China
Based on observed and simulated daily minimum temperature from three GMCs,the extreme cold spell taking into account three characteristics including the intensity,frequency,and duration was defined.The extreme value theory was applied to establish the Cold Spell Model(CSM).The bias correction method applied on the raw simulation and the future projection of CSM over southern China under global warming of 1.5 ℃ and 2 ℃ in the RCP4.5 scenario was studied.Results show that:(1)the CSM model can well represent the extreme cold spells based on observation,and most stations pass the K-S and chi-square test.(2)Compared to observation,climate model simulation exhibits quite large errors.The biases-corrected simulations can reduce the biases with the BS scores of each station closing to 0,and the SS score increasing to about 0.88.(3)Under 1.5℃ and 2.0℃ global warming,the intensity and frequency of extreme cold spell will decrease in most regions in the southern China.The large spatial variability was found for the changes in the duration of cold spell.The probability of events occurring once a year will increase,while the events occurring every 3 and 5 years will decrease.The direction of cold spell exhibit little changes under 1.5 ℃ warming world,while the probability of events with longer duration(3 and 5 days per year)will decrease.
extreme cold spellsextreme value modelbias correctionsfuture projection
万方数据
维普
