Are there any links between geomagnetic field variations and hydrological cycles in the South China Sea since the Late Pleistocene

A correlation between Earth’s magnetic field and climate change has been debated for over forty years, despite significant ~100- and ~41-kyr periods in both the stacked relative paleointensity and inclination records. In this paper, we construct a master relative intensity curve (SPIS-150) over the past ~150 kyr by stacking the data from one new core (PC27) with published intensity curves for the northern South China Sea. Additionally, we calculate the Dole effect from the sea surface temperature (SST) and d¹⁸O of planktonic foraminifera based on two cores, PC83 and PC27, and use it as a precipitation proxy. The results of this study show that geomagnetic field intensity lows are related to rich rainfall. During the ~23 kyr period, the relative intensity shows in-phase variations with simulating 0-30°N terrestrial precipitation, which shows that the superimposed effect of insolation and geomagnetic fields influences low-latitude precipitation. The strong summer monsoon predominated by insolation carries rich water vapor, which forms low cloud cover under one cloud-formation physical process where the geomagnetic field modulates galactic cosmic rays (GCRs) and leads to aerosol-related cloud condensation nuclei (CCN) formation. Deeper cloud cover produces strong rainfall in low-latitude regions.