Statistical Characterization of LGM and Late Holocene Oceanography in the Indonesian Maritime Continent

Daffa Zettira Mazdhania, Sandy Hardian Susanto Herho , Iwan Pramesti Anwar, Marfasran Hendrizan, Siti Nurzannah Kaban, Faruq Khadami, Rima Rachmayani, Sri Yudawati Cahyarini

This study provides a statistical characterization of surface oceanography in the Indonesian Maritime Continent (IMC) during the Last Glacial Maximum (LGM; 23–19 ka) and Late Holocene (LH; 4–0 ka). Using the lgmDA v2.1 paleoclimate data assimilation product, we analyze sea surface temperature (SST), sea surface salinity (SSS), and seawater $\delta^{18}$O. Results indicate the LGM was significantly cooler, saltier, and isotopically enriched, with reduced spatial heterogeneity compared to the LH. Comprehensive nonparametric testing confirms these differences reflect fundamental changes in distributional properties, not merely mean-state shifts. The findings suggest a major oceanographic regime shift, likely driven by lower sea levels, a weakened ITF, enhanced stratification, and a drier regional climate during the LGM. This work offers a statistical framework for understanding IMC sensitivity to glacial-interglacial forcing.