Paleo-tropical cyclone activity over the last millennium inferred from shipwreck relics in the Xisha Islands, northern South China Sea

Abstract

The prediction of the impact of long-term climate change on tropical cyclone (TC) activity has become a global concern, for which paleotempestology could provide crucial information about TC activity before instrumental archives. The ancient shipwrecks could alternatively be applied to retrieve paleo-TC activity owing to strong TC activity being among the dominant causes of historical shipwrecks. This study presents a preliminary study exploring the potential relationship between the shipwrecks and TC activity based on the compilation of shipwreck relics and chronological assessments of porcelains associated with the shipwrecks in the Xisha Islands, in the northern South China Sea (SCS). The compilation generally spans from the Song Dynasty to the Qing Dynasty (approximately 960 to 1850 CE), showing relatively enhanced shipwreck events during the time interval between 1400 and 1700 CE, consistent with the increased moisture and flood events during this period from other adjacent sedimentary records. Further analysis suggests that paleo-TC activity was controlled by multiple mechanisms concerning the El Niño Southern Oscillation (ENSO), the movement of the Intertropical Convergence Zone (ITCZ), and Asian dust emissions. Frequent ENSO events and the southward retreat of the ITCZ would have contributed to increased moisture in tropical regions promoting TC activity during the Little Ice Age (LIA), while the dust would strengthen TC activity through atmospheric circulations. Additional work combining the archaeological and sedimentary archives should be indispensable to further understand the climatic connections and potential mechanisms of TC processes, under climate change and relevant mitigation measures.