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An understanding of the oceanic response to tropical cyclones is of importance for studies on climate change, ecological variability and environmental protection. Hurricane Irma (2017, Atlantic Ocean) broke many records, including the fact that it was the first category 5 hurricane making landfall in Cuba since 1924. In this study, we assess the oceanic response of the waters of the Cuban Exclusive Economic Zone (EEZ) and the eastern Gulf of Mexico (GoM) to the passage of this hurricane. Overall, Irma led to a weak sea surface cooling in the EEZ, which was associated with the thermal structure of its waters and the fact that it was affected by the left-side quadrants of this hurricane. This cooling was driven by mixing and upwelling processes. In contrast, the chlorophyll-a (chl-a) concentration increase was comparable with climatological records, suggesting that horizontal advection of coastal waters and entrainment of chl-a rich waters from remote regions of the GoM influenced the post-storm chl-a concentration. Moreover, Irma increased the chl-a concentration in the northeastern GoM and stimulated the offshore transport of these chl-a-rich waters to the interior GoM. A high chl-a plume (HCP) extended southward across the eastern GoM during the first post-storm week of Irma, and these waters reached the northwestern Cuban coast following the Loop Current. An intensification of the geostrophic currents of an anticyclonic eddy at the upper front of the Loop Current, the formation of an anticyclonic-cyclonic eddy pair in the northeastern GoM and wind-driven advection governed the extension of this HCP. [ABSTRACT FROM AUTHOR]

In this work we assessed the spatio-temporal variability of the oceanographic conditions in the period 1998–2017 in four sectors of the Exclusive Economic Zone (EEZ) of Cuba, referred to as the northwest, northeast, southwest and southeast sectors (i.e., NWS, NES, SWS and SES, respectively). We relied upon remote-sensing observations of wind speed, sea surface temperature (SST), sea surface height anomaly (SSHA) and chlorophyll-a (chl-a) concentration along with model predictions of mixed layer depth (MLD), nitrate concentration and net primary production (NPP). We found evidence of the spatially heterogeneous oceanographic conditions of the EEZ of Cuba, since the analysed variables fluctuated spatially with meridional and zonal gradients. Overall, the southern sectors were warmer and less productive than the northern ones, thereby showing the influence of the Caribbean Sea. The NWS showed the highest variability of the physical and biological variables analysed, given the convergence of the Caribbean and the Gulf of Mexico waters and the Loop Current variability. The NES was strongly influenced by coastal conditions given its limited area and long coast line. Besides, a significant decadal increase in SSHA was linked to that in SST. Still, this warming trend was not reflected in the chl-a concentration and NPP trends, which is consistent with the fact that there has been no change over the studied 20 years in mean wind regime and MLD. Furthermore, the strong El Niño Southern Oscillation events of 1997–1998 and 2015–2016 appear to have considerably impacted the surface chl-a concentration, which was partially governed by the variability of the MLD. • The ocean surrounding Cuba has spatially heterogeneous oceanographic conditions. • The southern waters are warmer and less productive than the northern ones. • Significant sea level rise is associated to that in sea surface temperature. • There has been no change in mean chlorophyll-a concentration and productivity. • Strong El Niño Southern Oscillation events lead to strong biological responses. [ABSTRACT FROM AUTHOR]

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. • Hurricanes generate weak cooling and chlorophyll-a blooms. • Blooming-prone regions in the Gulf of Mexico positively impact chlorophyll-a. • Post-storm Island Mass Effect is 89. • Entrainment of remote chlorophyll-a governs the biological post-storm responses. • Using large spatial scales underestimates the hurricane-induced biological effects. [ABSTRACT FROM AUTHOR]