Arid Zone Research ›› 2018, Vol. 35 ›› Issue (2): 425-435.doi: 10.13866/j.azr.2018.02.22

• Climate and Climatic Resources • Previous Articles     Next Articles

Affecting Mechanism of Moisture Sources of Isotopes in Precipitation in the Tianshan Mountains Based on GCMs and Ice Core

YANG Sen1, ZHANG Ming-jun1, WANG Sheng-jie1,2   

  1. 1. College of Geography and Environment Science,Northwest Normal University,Lanzhou 730070,Gansu,China;
    2. State Key Laboratory of Cryospheric Sciences,Northwest Institute of Eco-Environment and Resources,Chinese Academy Sciences,Lanzhou 730000,Gansu,China
  • Received:2017-06-11 Revised:2017-07-22 Online:2018-03-15 Published:2025-11-17

Abstract: The interannual variations of δ18O from the GCMs and ice core were studied according to the six simulations of several isotope-equipped general circulation models (GCMs) (including the GISS-E(MERRA),GISS-E(NCEP),isoGSM(NCEP),LMDZ(free),LMDZ(ECMWF) and MIROC(free)) and the data of δ18O from the Miaoergou ice core. By correlation analysis,the six simulations of isotope-enabled GCMs and the δ18O data from ice core were analyzed.Six simulations of isotope-enabled GCMs data and the ice core data were involved,and the monthly series of stable oxygen isotopes in precipitation for each grid were applied to calculate the linear trends.By observing the change trend of δ18O data from ice core and simulated data,the most suitable isotope-enabled general circulation model (GCM) was selected to analyze the data of δ18O in precipitation in the Tianshan Mountains,and the sources of water vapor in the most suitable model were further analyzed.The results showed that there was a “temperature effect” in the results simulated with GCMs on an interannual timescale.Generally,the correlation between oxygen isotope composition and surface air temperature on interannual timescale was lower than on seasonal timescale.The trend of MIROC(free) model was similar to that of the Miaoergou ice core (a=-0.01).MIROC(free) model was the most suitable model used to simulate the values of δ18O in precipitation in the Tianshan Mountains,and the result from the MIROC(free) model was similar to the measured one.The direction and proportion of water vapor sources determined the poverty or enrichment degree of δ18O in precipitation.Based on the continuous wavelet transform methods,the strongest energy occurred during the period from 1990 to 2001.Even though the values of δ18O in precipitation during the period from 1990 to 2001 presented many positive fluctuations,a significant decrease trend was characterized in general.After observing the vapor source trajectories,the increased water vapor from the Arctic Ocean resulted in a significant decrease trend of δ18O in precipitation,and the increased water vapor from the mid-latitude Atlantic caused many increasingly fluctuations of δ18O.

Key words: GCMs, ice core, water vapor source, stable water isotopes, Miaoergou, Tianshan Mountains