Dry air outbreak and significant surface turbulent heat loss during Hurricane Ian: satellite and saildrone observations

Abstract

This study investigates an exceptional Gulf of Mexico dry air outbreak triggered by Hurricane Ian and fueled by dry air originating from drought-stricken mid-latitudes under a high-pressure system. The convergence of meteorological forces, combining cooler, dry air with a warmer, humid sea surface and strong winds, intensified latent and sensible heat exchanges, resulting in significant oceanic heat loss. Data from the 2022 Atlantic hurricane Saildrone mission and satellite flux analysis revealed that the outbreak's total turbulent heat fluxes peaked above 850 Wm−2, comparable to or even surpassing the hurricane’s impact. Argo float measurements recorded a 40-m deepening of the mixed layer and a 1.4°C temperature decrease. In the tropical Atlantic, wind effects outweighed humidity in driving flux variability. Saildrone’s high-frequency linewise measurements, distinct from satellite’s footprint averages, provide unique insights into wind variability under high wind conditions.