Simulation And Comparison Of Stable Isotopic GCM In Global Precipitation

In terms of spatial variations of global ?¹⁸O in precipitation,we used simulated data from ten GCM models equipped with water stable isotopes,and analyzed the spatial distribution characteristics about environmental effect of oxygen stable isotope in global precipitation.Meanwhile,we compared different simulated results coupled with simulated values and the GNIP measured values.Our aims are to evaluate the simulative validity of different stable isotope atmospheric circulation models and improve our understanding and cognition for stable isotopic effect in water cycle.The results indicate that isoGSM,ECHAM4,LMDZ4 and HadAM3 show gpod performance in simulating the global distribution of?¹⁸O.All models do well in simulating the seasonal difference of ?¹⁸O in spatial distribution expect the HadAM3 model.The models performances of isoGSM,GISS E-F,ECHAM4,GISS E-N and LMDZ4 in simulating the relationship between ?¹⁸O and air temperature in spatial distribution are close to the measured results.LMDZ4,isoGSM,GISS E-F,ECHAM4 and MUGCM models have stronger capacity in the aspect of simulating relationship between ?¹⁸O and precipitation amount in spatial distribution.GISS E-F,isoGSM and GISS E-N models have more advantages in simulating the global meteoric water li'ne.In terms of temporal variations of global ?¹⁸O in precipitation,firstly,we used data from eight isotopic general circulation models to analysed the seasonal variations and the reasons of ?¹⁸O in precipitation from global 13 typical climate stations.What's more,we evaluated the models performance with GNIP measured data.The results indicate that the 3 models LMDZ4,GISSE-N and ECHAM4 have good simulative performance overall.The reasons for the seasonal variations of ?¹⁸O among different stations can be attributed to different vapor sources during different seasons,the seasonal difference of precipitation in vapor transport path and the seasonal difference of sub-cloud secondary evaporation.Secondly,this paper analysed the relationship between ?¹⁸O inter-annual variation in Hong Kong precipitation and atmospheric general circulation anomaly towards vapor transportation.?¹⁸O measured values and simulated values in Hong Kong also be compared,the results indicate that the two models ECHAM4 and LMDZ4 can simulate the negative correlation between annual ?¹⁸O in Hong Kong and corresponding southern oscillation index?SOI?.Then we analysed different situation of vapor transportation and precipitation during 1998 and 1999 summer toward to ?¹⁸O in Hong Kong precipitation,we can draw the conclusion that inter-annual vapor source variation and precipitation variation of vapor transport path upstream are the reasons for inter-annual variation of ?¹⁸O in Hong Kong precipitation.Based on the simulative results of water stable isotope atmospheric general circulation model ECHAM4.This part firstly anallyzed the distribution of global vapor evaporation area,vapor flux characteristics in different latitudes and distribution differences of global precipitation,and explained the distribution characteristics of ?¹⁸O in global precipitation.Afterwards,based on the quantitative analysis of Rayleigh equilibrium fractionation formula and model vapor transportation and precipitation values in January and July,we explained the reasons of positive correlation between ?¹⁸O in precipitation and temperature in high latitude area and the reasons of negative correlation between ?¹⁸O in precipitation and temperature in subtropical ocean in detail Finally,based on the analysis influence of large scale vapor transportation seasonal variation to?¹⁸O in precipitation,we explain the reasons of ?¹⁸O in precipitation and temperature present different Correlational relationship between Chinese monsoon area and non-monsoon area.This conclusions discuss distribute rule of global water stable isotope and the correction of which with temperature in the aspect of vapor resources and transportation characteristic.