表层雪中稳定同位素季节变化及其与水汽输送的关系——以天山乌鲁木齐河源1号冰川积累区为例

根据2002年9月至2005年12月在天山乌鲁木齐河源1号冰川积累区采集的表层雪样品,揭示了该区表层雪中δ<'18>O值的季节变化特征,讨论了水汽输送对降水中δ<'18>O值变化的影响.研究表明,天山乌鲁木齐河源1号冰川表层雪中δ<'18>O值季节变化显著,变幅可达12.59‰左右,其变化趋势和气温的变化趋势基本一致,...

Seasonal variations of stable oxygen isotope in surface snow and vapor transportation at the headwaters of Urumqi River,Tianshan Mountains

Discussion on δ¹⁸O values in 40 samples of surface snow collected from September 2002 to December 2005 on the east branch of Glacier No. 1 at the headwaters of Urumqi River, eastern Tianshan Mountains (43°06''N, 86°49''E, 4130 m a.s.l.) is presented. Seasonality of δ¹⁸O values in surface snow is analyzed, as well as the effects of different moisture transportation on δ¹⁸O values in atmospheric precipitation. The research result indicates that a significant seasonal variation of δ¹⁸O values is found in surface snow, which is similar to air temperature in tendency; δ¹⁸O values in wet season is generally above that in dry season, with the range of 12.59‰. There is a positive correlation between air temperature and δ¹⁸O values. However, many factors may contribute to the variation of δ¹⁸O values during post-depositional process (e.g.snow drifting, seasonal snow melt water, surface snow refreezing and mass-exchange between snow and atmosphere), and alter the significant relationship between air temperature and δ¹⁸O values in surface snow. And the coefficient is high in wet season (0.76) and low in dry season (0.57). Different transmission source of moisture is another main factor affecting the seasonal variation of δ¹⁸O values in precipitation. Transportation distance and characteristic of vapor have a certain influence on variation of δ¹⁸O values in precipitation. Based on the HYSPLIT air trajectory model, vapor source in dry season is closely related to water transmission controlled by Westerlies, while that in wet season is strongly influenced by regional and local air mass. And at the junction for different seasons, both the two sources have effect on this area.