Geographically metachronous pattern of tropical cyclone activities across the western Atlantic basin

Keywords: paleotempestology, tropical cyclone, hurricane, the Atlantic basin, Nicaragua, ITCZ, Bermuda High
Abstract Type: Paper Abstract

Abstract

North Atlantic tropical cyclones display large spatial and temporal variability. One hypothesis argues that the level of TC activity is relatively constant across the Atlantic basin at any one time, with shifts in activity levels occurring synchronously across North America, with the likely forcing agents being Atlantic sea surface temperature, the frequency of ENSO events, and the strength of the west African monsoon. A competing hypothesis suggests that changes in landfall frequency at any one location may merely reflect changes in steering controls and location of landfall, rather than changes in overall TC frequency. Here we present a 7000-year paleo-storm record based on two cores extracted from the floodplain of the Rio Prinzapolka along the coast of Nicaragua, the southmost limit of Atlantic hurricane activities. Increased fluvial, mixed, and marine event deposit layers are distinguished from both cores during the periods between ~4000 and 2200 cal yr BP and between 800 and 0 cal yr BP. Moreover, the TC activity regime from Nicaragua is anti-phase with that from the east coast of North America, and the Nicaragua activity regime also corresponds with the southward shift of the ITCZ. Thus, it is reasonable to conclude that the North American hurricane regime is driven by the latitudinal movement of the North American circulation system, especially such key features as the Intertropical Convergence Zone and the Bermuda High.