Different Dynamics Drive Indian Ocean Moisture to the Southern Slope of Central Himalayas: An Isotopic Approach

This study uses precipitation oxygen isotopes (δ 18 O p ) to examine key dynamics that deliver moisture to the southern slope of central Himalayas over different seasons. Results show that the majority of pre‐monsoon δ 18 O p values are relatively high and controlled by the westerlies and local moisture. However, some abnormally low δ 18 O p values coincide with higher precipitation amounts during the pre‐monsoon season due to moisture driven northwards from the Bay of Bengal and Arabian Sea to central Himalayas by anomalous circulations (quasi‐anticyclone, anticyclone, or/and westerlies trough). The size and location of the quasi‐anticyclone also influences the magnitude of the δ 18 O p decrease. In comparison, the monsoon δ 18 O p values are lower due to the combined effects of the Indian summer monsoon and convection. Our findings indicate that researchers need to consider the signals of abnormally low δ 18 O p values during the pre‐monsoon season when attempting to interpret ice core and tree‐ring records from central Himalayas.