Interannual Variation in Stable Isotopes in Water Vapor Over the Northern Tibetan Plateau Linked to ENSO

摘要

The contrasting responses of ice core δ~(18)O records (δ~(18)O_(ice)) from the northern and southern Tibetan Plateau (TP) to the El Nino Southern Oscillation (ENSO) complicate δ~(18)O_(ice)-based temperature reconstructions. These contrasting responses were explored using stable hydrogen isotopes in water vapor (δD_v). We found that the interannual variation in δD_v from the northern TP is influenced by midtropospheric moisture sources from the Indo-Pacific Warm Pool, with enriched (depleted) δD_v values in La Nina (El Nino) years due to enhanced (weakened) deep convection. In comparison, the interannual δD_v variation in the southern TP is mainly influenced by low-tropospheric moisture from the central Indian Continent, whose δD_v is depleted (enriched) in La Nina (El Nino) years. These results demonstrate that moisture transported from different altitudes can lead to opposite isotopic signals of water vapor over the northern and southern TP and can be used to reconcile the contrasting responses of δ~(18)O_(ice) to ENSO.