HYSPLIT Back-trajectory script for Figure 1 in "Contrasting drivers of South Asian summer and winter monsoon evolution during the last deglaciation"

This dataset contains the code, and supporting input data used to generate the HYSPLIT back-trajectory analyses presented in Figure 1 of the study “Contrasting drivers of South Asian summer and winter monsoon evolution during the last deglaciation.” The trajectories were calculated to characterize atmospheric transport pathways associated with the South Asian summer and winter monsoon systems and to assess seasonal moisture source regions influencing the northeastern Arabian Sea and the middle Indus catchment. The repository includes scripts for generating 240-hour backward air-mass trajectories for winter (December–February) and summer (June–August) conditions using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model developed by National Oceanic and Atmospheric Administration and the Air Resources Laboratory. The workflow reproduces the trajectory fields shown in Figure 1b and 1d, including spatial averaging over the selected source region and visualization of seasonal circulation patterns. The associated figure combines HYSPLIT trajectory outputs with seasonal precipitation fields derived from WorldClim to illustrate contrasting summer and winter precipitation regimes across the Indian subcontinent and surrounding regions. The study site offshore Pakistan is highlighted together with additional paleoclimate archives discussed in the manuscript, including Bittoo Cave, Timta Cave, Mawmluh Cave, and several lake records across South and East Asia.