Evaluation Of The Climate Change With 5 LUCCs And 3 LSMs Using WRF In China Land Area

This study investigates responses of surface climates and extreme to land surface models(LSMs)and Land use and land cover change(LUCC)over various time-scales in China using a 10-yr WRF simulation.Applied with three land surface models(CLM,NOAH and RUC)and five land use and land cover change(MODIS,HH,HYDE,RF and CESM),the WRF model was integrated for 1996-2005,and model produced surface climate,energy balance,and extremes are firstly compared with observations including ECMWF,CN05.1 and APHRO.The cross-comparison of model performances with different LSMs and LUCCs is conducted to assess the sensitivity and uncertainty of regional climate to land surface processes.And the impacts of LUCC and LSM on simulated regional extremes are analyzed.The study can provide insight as to the relative contributions of maps of LUCC and LSMs to regional climate change,as well as the temporal-spatial characters of responses of surface and extreme climate to the LUCC.From this study the following conclusions can be drawn:(1)All three experiments with CLM,NOAH and RUC can reproduce the annual spatial pattern of climates well,particularly for temperature.The differences between LSMs for modeled precipitation are more evident than temperature.However,the performance of WRF shows dependence on sub-regions.CLM and RUC overestimates the seasonal averaged temperature in east China in summer and fall and in northwest of China in winter.And underestimation of NOAH experiment can be found in simulating annual and seasonal averaged temperature in summer and autumn over most part of China.As for MAM and JJA seasonal averaged precipitation,all LSMs represent overestimation over south of China,where the amount of rainfall is considerable.Comparing the different time-scale results,the three LSMs simulate seasonal variation most accurately,followed by interannual variation for temperature.The three LSMs experiments model the peaks of diurnal cycle for temperature about 3 hours later than observation over west of China.RUC performs worse than other LSMs for interannual variation of simulated precipitation for the drier summers,with large underestimation for domain-averaged precipitation over south China,northeast China and northwest China.(2)Eastern China appears to be more sensitive to LSM when extreme temperature is concerned.The best simulation of Tmax90p is provided by NOAH,while for summer Tmin10p is by CLM.Overestimations of Trange are demonstrated in all three LSM runs over monsoon-dominated sub-regions.Larger sensitivities of Prec90p,SD?,and R10 to options of LSMs also appeared in eastern China in the summer,as the sensitivity of CDD to LSMs in the northwestern region.(3)In regional climate simulations,the uncertainty arising from the LUCC is less than that from LSMs.Moreover,in the LSM-LUCC simulation matrix,RUC is the least sensitive to the changing LUCCs while CLM shows the largest response.Summer climate demonstrates larger responses to LUCC,especially over Qinghai-Tibet Plateau and southern China.The extreme indices Prec90p,SDII,and R10 have similar pattern of responses to LUCC and LSM as for the temporal and spatial characters,LUCC shows more influences on climatology of precipitation,but has a greater impact on the simulation of extreme temperature indices.(4)The correlation between heat fluxes and climate is evaluated,which shows strong dependence on regions and seasons.The significant influences of sensible heat flux and latent heat flux can be found over east China in summer.The combined influence of surface heat fluxes on precipitation simulation can be more evident in sub-regions with rainfall belts associated with East Asia monsoon and Tibet Plateau in summer.For winter,the correlation between heat fluxes and precipitation is small,but heat fluxes show significant impact on CDD over west of China.