Comparison of GCM-simulated isotopic compositions of precipitation in arid central Asia

Abstract

The isotope-equipped GCMs (general circulation models) are useful tools to investigate the isoscape in precipitation and water vapor, especially for the regions without enough in-situ observations. To study the spatial distribution and seasonal variation of precipitation isotopic composition in arid central Asia, several isotope-equipped GCMs are applied, and the long-term observations in two stations are used to verify the GCM-simulated results. Generally, seasonality of isotopic composition can be well simulated in each GCM, and the values of δ 18 O in precipitation are larger in summer months (from April to October) and lower in winter months (from November to March). Higher latitude usually shows lower values of δ 18 O in precipitation, and lower latitude has higher values. The values of δ 18 O are relatively low in the eastern section, and higher in the western section. Among these simulations, ECHAM is good at describing the isotopic composition in the study region, which can be seen from the mean absolute error (MAE) and root-mean-square error (RMSE). The ECHAM-derived values of δ 18 O in precipitation positively correlate with the observed series, and the correlation coefficient based on ECHAM is the largest among these GCMs.

Water Source Signatures in the Spatial and Seasonal Isotope Variation of Chinese Tap Waters

“…The model runs used here were nudged with National Centers for Environmental Prediction (NCEP) reanalysis data (Risi et al, 2012;Sturm et al, 2010). Among several isotope-enabled GCMs that participated in SWING2, the isoGSM model showed credible performance in China, and the comparison between GNIP/CHNIP observations and GCM simulations was shown in previous studies (e.g., Che et al, 2016;Wang et al, 2015;Yang et al, 2017).…”

Factors controlling stable isotope composition of precipitation in arid conditions: an observation network in the Tianshan Mountains, central Asia

“…The GNIP station Urumqi (87837?E,43847?N, 918 m a.s.l., station code 5182801), located on the northern slope of the Tianshan Mountains, has monthly precipitation isotope data for the years 1986Á1992, 1995Á1998 and 2001Á2003 (IAEA/WMO, 2014Wang et al, 2015). In 2004, a nationwide network named CHNIP (China Network of Isotopes in Precipitation) was established, and the Fukang station (87856?E, 44817?N, 460 m a.s.l.)…”

Impacts of Climate Change and Different Crop Rotation Scenarios on Groundwater Nitrate Concentrations in a Sandy Aquifer

“…General circulation models (GCMs) have been developed to provide global-scale climate projections and have been widely used worldwide. The GCMs can be further downscaled at a finer resolution to obtain more realistic local-scale climate projections by using statistical or dynamical downscaling techniques [34]. Regional climate models (RCMs) are available for many regions across Canada [34].…”

“…The GCMs can be further downscaled at a finer resolution to obtain more realistic local-scale climate projections by using statistical or dynamical downscaling techniques [34]. Regional climate models (RCMs) are available for many regions across Canada [34]. Extracted future climate data can be inputted into groundwater modeling tools to examine the impact of climate changes on groundwater quantity and quality.…”