The African meridional OLR contrast as a diagnostic for Atlantic tropical cyclone activity and implications for predictability

Abstract

The interannual variability of outgoing longwave radiation (OLR) over Africa from the Advanced Very High Resolution Radiometer (AVHRR) and zonal wind speed in the African easterly jet (AEJ) is analyzed and discussed in the context of Atlantic tropical cyclone activity. It is found that hurricane and tropical storm totals in the Atlantic basin are closely related to the African meridional OLR contrast (AMOC). It is suggested that the AMOC provides a simple yet novel way to simultaneously characterize the meridional temperature gradient and ITCZ activity, both of which play integral roles in generating African easterly waves. Complimentary to observed relationships between Sahel rainfall and Atlantic tropical cyclone activity, the potential for the AMOC to augment existing techniques used in preparing Atlantic hurricane season outlooks is also discussed. Copyright 2006 by the American Geophysical Union.