Is Basin Averaging Enough? Understanding The Atlantic Sea Surface Temperature - Tropical Cyclone Relationship

The majority of works investigating future Atlantic tropical cyclone (TC) frequency in a warming environment employ a simulation-based approach. Observational data-driven analyses meanwhile, have focused on basin-wide trends to conclude that no clear relation can be attributed to the recent increase in Atlantic sea surface temperature (SST) and Atlantic TC frequency. We present a data-driven analysis that monitors smaller regions in the Atlantic and is able to capture connections between the warming of certain regions in the Atlantic ocean and Atlantic TC frequency better than the previously used basin-wide analyses. Our results suggest that the warming of the Atlantic off the West African coast near 20- 30N prior to the TC season (May-June), as well as the warming westward of 10 - 20N between 18 and 60W during the TC season (July-October) have a pronounced effect on TC formation. Furthermore, we propose that, unlike other basins, the recent increase in TC activity can be partially linked to increased Atlantic SST in the regions identified. This work was supported by NSF grants IIS-0905581 and IIS-1029711.