Fig. 4: The sources of moisture that enhance tropical and subtropical EASM precipitation during the MPWP through thermodynamic and dynamic processes.

Left panel: the vertically integrated water vapor transport throughout the troposphere is represented by the moisture fluxes (\(\langle q\cdot {{\bf{V}}}_{H}\rangle\), units: kg m−1 s−2) in JJA for PI (a) and MPWP periods (c) and the differences between MPWP and PI periods (e). Right panel: horizontal wind vector at 850 hPa (units: m s^−1) in JJA for PI (b), MPWP (d) and differences between MPWP and PI periods (f). The colored circles in (e, f) are 11 proxy records with precipitation increase within EASM domain. The strongest moisture pathway into the EASM domain, sustaining the mean state of EASM precipitation, is depicted by the blue rectangle in (a, c).