To what extent could water isotopic measurements help us understand model biases in the water cycle over Western Siberia

Abstract

Abstract. We evaluate the isotopic composition of water vapor and precipitation simulated by the LMDZ (Laboratoire de Météorologie Dynamique-Zoom) GCM (General Circulation Model) over Siberia using several data sets: TES (Tropospheric Emission Spectrometer) and GOSAT (Greenhouse gases Observing SATellite) satellite observations of tropospheric water vapor, GNIP (Global Network for Isotopes in Precipitation) and SNIP (Siberian Network for Isotopes in Precipitation) precipitation networks, and daily, in situ measurements of water vapor and precipitation at the Kourovka site in Western Siberia. LMDZ captures the spatial, seasonal and daily variations reasonably well, but it underestimates humidity (q) in summer and overestimates δD in the vapor and precipitation in all seasons. The performance of LMDZ is put in the context of other isotopic models from the SWING2 (Stable Water Intercomparison Group phase 2) models. There is significant spread among models in the simulation of δD, and of the δD-q relationship. This confirms that δD brings additional information compared to q only. We specifically investigate the added value of water isotopic measurements to interpret the warm and dry bias featured by most GCMs over mid and high latitude continents in summer. The analysis of the slopes in δD-q diagrams and of processes controlling δD and q variations suggests that the cause of the dry bias could be either a problem in the large-scale advection transporting too much dry and warm air from the south, or too strong boundary-layer mixing. However, δD-q diagrams using the available data do not tell the full story. Additional measurements would be needed, or a more sophisticated theoretical framework would need to be developed.

Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle

“…When the retrieval sensitivity and orbital sampling are accounted for, we can conclude that the LMDz model underestimates the HDO/H 2 O in the tropics and overestimates it at high latitudes such that the modeled latitudinal gradient is smaller than observed. This underestimate of the latitudinal gradient is a consistent feature with global hydrological models [e.g., Field et al, 2010;Risi et al, 2013;Gryazin et al, 2014]. We can test whether a hypothesis is related to some aspect of the model physics by adjusting the corresponding parameter in the model and determining if the difference between the adjusted model and data is improved.…”

“…Over the northern hemispheric continents, isotopic variations can primarily be explained in terms of the temperature and continent effects. For example, water vapor becomes gradually more depleted with lower temperature (higher latitudes) or as air parcels travel from Europe to Siberia [ Gryazin et al , ]. Important differences in isotopic variations are apparent in tropical regions.…”

Moisture origin and stable isotope characteristics of precipitation in southeast Siberia

“…Consequently, stable isotopes have a great potential to provide unique information on atmospheric circulation patterns and climate changes. In recent years, the stable isotope composition of precipitation has become one of the most reliable tools for meteorological, climatological, and hydrological studies (Bowen, 2010; Tang et al, 2017; Wei, Lee, Liu, Seeboonruang, & Koike, 2018; Wu, Zhang, Xiaoyan, Li, & Huang, 2015; Yang et al, 2019) and modelling (Bowen, 2008; Butzin et al, 2014; Gryazin et al, 2014; Werner, Langebroek, Carlsen, Herold, & Lohmann, 2011; Yao et al, 2013). In addition, data on isotope composition of modern precipitation are widely used for decoding information about past climate conditions stored in natural archives (Rozanski, Johnsen, Schotterer, & Thompson, 1997) such as lake sediments (Kostrova, Meyer, Chapligin, Tarasov, & Bezrukova, 2014; van Hardenbroek et al, 2018), ground ice (Meyer et al, 2015; Meyer, Dereviagin, Siegert, Hubberten, & Rachold, 2002), firn/ice cores (Casado, Orsi, & Landais, 2017; Fernandoy, Meyer, & Tonelli, 2012; Pang, Hou, Kaspari, & Mayewski, 2014), tree rings (e.g., Leonelli et al, 2017), and cave stalagmites (Liang et al, 2015; Partin et al, 2012).…”

Moisture sources and synoptic to seasonal variability of North Atlantic water vapor isotopic composition

“…Measurements of atmospheric water stable isotopes (H 2 16 O, HD 16 O, H 2 18 O, H 2 17 O) provide integrated information related to hydrological cycle processes and offer the potential to constrain associated parameterizations in atmospheric models and potentially improve weather predictions [e.g., Yoshimura et al ., ; Gryazin et al ., ].…”