Orbital Forcing of Arabian Peninsula Hydroclimate from the Last Glacial to Present

The Arabian Peninsula experienced pronounced hydroclimate shifts during the last 20,000 years, driven by orbitally forced changes in insolation that modulated monsoon strength, ITCZ position, and large-scale atmospheric circulation across distinct climate regimes. Using the LOVECLIM Earth system model, we reconstruct temperature and precipitation evolution across northern, central, and southern Arabia from the Last Glacial Maximum to the present, and evaluate the underlying mechanisms using orbital parameters and associated changes in tropical–extratropical circulation. The simulations reproduce key features observed in regional proxy archives, including early Holocene humid conditions, the 8.2 ka monsoon weakening, mid-Holocene aridification, and the establishment of modern desert climates after 4 ka BP. Precession emerges as the dominant control on monsoon intensity and rainfall in central and southern Arabia, whereas obliquity exerts the strongest influence in northern Arabia by modulating meridional temperature gradients and the poleward extent of monsoon penetration. Eccentricity acts as a low-frequency amplifier of precessional forcing, shaping the pacing and amplitude of humid–arid cycles. The modeled ITCZ position shows a major northward shift to approximately 25–28°N during the early Holocene, consistent with enhanced monsoon penetration, followed by a progressive southward retreat through the mid- to late Holocene. These results demonstrate that Arabia lies at the intersection of tropical and extratropical forcing regimes, where the interaction between precession-driven monsoon dynamics and obliquity-driven circulation changes governs spatially heterogeneous hydroclimate responses. This study provides an integrated framework for interpreting regional proxy records and highlights the mechanisms linking astronomical forcing to long-term hydroclimate evolution in the Arabian Peninsula.