Abstract
AbstractThe paper presents oxygen and hydrogen isotopes of 284 precipitation event samples systematically collected in Irkutsk, in the Baikal region (southeast Siberia), between June 2011 and April 2017. This is the first high‐resolution dataset of stable isotopes of precipitation from this poorly studied region of continental Asia, which has a high potential for isotope‐based palaeoclimate research. The dataset revealed distinct seasonal variations: relatively high δ18O (up to −4‰) and δD (up to −40‰) values characterize summer air masses, and lighter isotope composition (−41‰ for δ18O and −322‰ for δD) is characteristic of winter precipitation. Our results show that air temperature mainly affects the isotope composition of precipitation, and no significant correlations were obtained for precipitation amount and relative humidity. A new temperature dependence was established for weighted mean monthly precipitation: +0.50‰/°C (r2 = 0.83; p <.01; n = 55) for δ18O and +3.8‰/°C (r2 = 0.83, p < 0.01; n = 55) for δD. Secondary fractionation processes (e.g., contribution of recycled moisture) were identified mainly in summer from low d excess. Backward trajectories assessed with the Hybrid Single‐Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicate that precipitation with the lowest mean δ18O and δD values reaches Irkutsk in winter related to moisture transport from the Arctic. Precipitation originating from the west/southwest with the heaviest mean isotope composition reaches Irkutsk in summer, thus representing moisture transport across Eurasia. Generally, moisture transport from the west, that is, the Atlantic Ocean predominates throughout the year. A comparison of our new isotope dataset with simulation results using the European Centre/Hamburg version 5 (ECHAM5)‐wiso climate model reveals a good agreement of variations in δ18O (r2 = 0.87; p <.01; n = 55) and air temperature (r2 = 0.99; p <.01; n = 71). However, the ECHAM5‐wiso model fails to capture observed variations in d excess (r2 = 0.14; p < 0.01; n = 55). This disagreement can be partly explained by a model deficit of capturing regional hydrological processes associated with secondary moisture supply in summer.
Highlights
Climate change and its impacts on weather conditions and ecosystems at the global and regional scale has become an important issue for science, economy, and politics in recent decades (Intergovernmental Panel on Climate Change, 2014)
Climate proxy records derived from sedimentary archives worldwide play an important role in reconstructing past changes in atmospheric circulation and precipitation, extending our knowledge beyond the relatively short interval covered by instrumental measurements and satellite data
This paper presents 5 years of event-based precipitation isotopes for the city of Irkutsk (2011–2017) including its statistical characteristics, correlation with key meteorological parameters to fill a significant gap in the Siberian precipitation isotope network
Summary
Climate change and its impacts on weather conditions and ecosystems at the global and regional scale has become an important issue for science, economy, and politics in recent decades (Intergovernmental Panel on Climate Change, 2014). The detailed understanding of circulation processes and background mechanisms controlling precipitation of a given region and its temporal and spatial variations is an important issue for assessment and forecast of weather and water regimes worldwide (Bailey, Klein, & Welker, 2019; Brázdil, 1992; Tang et al, 2017; Trenberth, 2011). Variations in stable isotope composition (δD and δ18O) of precipitation are caused by isotope fractionation processes occurring at phase transitions in the hydrological cycle (Dansgaard, 1964) They correlate with climatic parameters such as air temperature, humidity, and precipitation amount (Dansgaard, 1964; Rozanski, Araguás-Araguás, & Gonfiantini, 1993) and are defined by air mass trajectories (Kurita, 2011; Merlivat & Jouzel, 1979). 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)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
