Abstract:

The Altay Mountains located in the middle of the Eurasian continent are one of the key areas of climate research in the mid-latitude westerlies. On the basis of the data collected from the four stations across the Altay Mountains, the intra-annual variations of stable hydrogen and oxygen isotopes in precipitation and the meteoric water lines were investigated. The temperature effect on precipitation isotopes was examined, and the water vapor sources were analyzed using backward trajectory. The following results were obtained. (1) The isotope ratios in precipitation are higher in summer and lower in winter, and the seasonal difference in the southern side is larger than that in the northern side. The deuterium excess value in precipitation is lower in summer and higher in winter at most stations, except for Novosibirsk. (2) The slope and intercept of meteoric water lines are lower than the global average at most stations, except for Novosibirsk. (3) The isotope ratios in precipitation have an obvious temperature effect, which can be seen from seasonal variations and spatial patterns. (4) The backward trajectory indicates a joint influence of the westerlies, the polar air mass, and the locally evaporated water vapor, and the northern stations may be more influenced by the polar path than other stations. These findings are useful for understanding the hydrological and climate information about stable precipitation isotopes across different parts of the Altay Mountains and provide a reference for investigating regional atmospheric water cycle and climate change.

Key words: precipitation isotope, backward trajectory, water vapor source, Altay Mountains