The impact of hurricanes on the oceanographic conditions in the Exclusive Economic Zone of Cuba

Abstract In this work, we analysed the satellite-based responses of sea surface temperature (SST) and chlorophyll-a (chl-a) concentration in the waters of the Exclusive Economic Zone (EEZ) of Cuba to hurricanes that crossed the EEZ between 1998 and 2016 as well as the environmental drivers governing the post-storm responses. We considered two spatial scales to capture the spatially heterogeneous nature of the effects of hurricanes. A first more fine-grained one where we considered 120 km radius disks centered at every consecutive hurricane position within the EEZ (scale 1) and a second more coarse grained one enclosing the entire EEZ (scale 2). We conclude that the hurricanes induced a weak cooling since 75 and 85% of the SST anomalies at scale 1 and 2, respectively, were smaller than −1 °C. The sea surface cooling was mainly caused by wind-driven processes. The maximum chl-a responses were recorded in the first and second post-storm weeks, with 60% ranging between −0.01 and 0.04 mg m−3 at scale 1, and between −0.07 and 0.02 mg m−3 at scale 2. During those post-storm weeks SST and chl-a anomalies were 18 and 44% higher at scale 1 than at scale 2, respectively. We argue that the transport of chl-a from the deep chlorophyll maximum and/or the rich coastal waters are the dominant mechanisms determining the post-storm chl-a response in the EEZ. We also found that the magnitude of the Island Mass Effect (i.e., increase of chl-a concentration in waters surrounding islands) after the passage of the hurricanes was 89% higher in the EEZ than before its passage.