LAUSR

The contrasting responses of ice core δ18O records (δ18Oice) from the northern and southern Tibetan Plateau (TP) to the El Niño Southern Oscillation (ENSO) complicate δ18Oice‐based temperature reconstructions. These contrasting responses were explored using stable hydrogen isotopes in water vapor (δDv). We found that the interannual variation in δDv from the northern TP is influenced by midtropospheric moisture sources from the Indo‐Pacific Warm Pool, with enriched (depleted) δDv values in La Niña (El Niño) years due to enhanced (weakened) deep convection. In comparison, the interannual δDv variation in the southern TP is mainly influenced by low‐tropospheric moisture from the central Indian Continent, whose δDv is depleted (enriched) in La Niña (El Niño) 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 δ18Oice to ENSO.