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Just about everything that we experience on Earth depends upon the ocean circulation. Intended for a general lay-person audience, or as a non-science major undergraduate text, this book explains (in a non-mathematical manner) how the ocean circulation and the ocean's interactions with the atmosphere provides the basic underpinnings for global climate and ecology.

The central portion of the west Florida continental shelf is the epicenter for blooms of the harmful alga Karenia brevis, which tends to form at mid-shelf under nutrient depleted, or oligotrophic, conditions. Whether or not the shelf is conducive to such bloom formation in any given year appears to be related to when and where the Gulf of Mexico Loop Current, a western boundary current, interacts with the shelf slope. If this occurs in the southwest corner, where shallow isobaths wrap around the Florida Keys at the Dry Tortugas, then the entire west Florida shelf may be set into a protracted upwelling circulation that can both reset water properties and transport mid-shelf materials to the shoreline within the bottom Ekman layer. The 2018 K. brevis bloom provides one such example, as described via a coordinated program of coastal ocean observing and modeling. Both the elevation of K. brevis cell counts along the coast and their eventual cessation may be largely accounted for by the coastal ocean circulation, as driven, in part, by the Loop Current’s interaction with the shelf slope.

The Lagrangian separation distance between the endpoints of simulated and observed drifter trajectories is often used to assess the performance of numerical particle trajectory models. However, the separation distance fails to indicate relative model performance in weak and strong current regions, such as a continental shelf and its adjacent deep ocean. A new skill score is proposed based on the cumulative Lagrangian separation distances normalized by the associated cumulative trajectory lengths. This skill score is used to evaluate surface trajectories implied by Global HYCOM hindcast surface currents as gauged against actual satellite‐tracked drifter trajectories in the eastern Gulf of Mexico during the 2010 Deepwater Horizon oil spill. It is found that the new skill score correctly indicates the relative performance of the Global HYCOM in modeling the strong currents of the Gulf of Mexico Loop Current and the Gulf Stream and the weaker currents of the West Florida Shelf. In contrast, the Lagrangian separation distance alone gives a misleading result. The proposed dimensionless skill score is particularly useful when the number of drifter trajectories is limited and neither a conventional Eulerian‐based velocity nor a Lagrangian‐based probability density function may be estimated. Key Points A new skill score is proposed to evaluate trajectory model It correctly assesses the relative HYCOM performance in Loop Current and shelf regions It is especially useful in sparse drifter trajectories

A recently developed tool, the multiscale window transform, along with the theory of canonical energy transfer is used to investigate the roles of multiscale interactions and instabilities in the Gulf of Mexico Loop Current (LC) eddy shedding. A three-scale energetics framework is employed, in which the LC system is reconstructed onto a background flow window, a mesoscale eddy window, and a high-frequency eddy window. The canonical energy transfer between the background flow and the mesoscale windows plays an important role in LC eddy shedding. Barotropic instability contributes to the generation/intensification of the mesoscale eddies over the eastern continental slope of the Campeche Bank. Baroclinic instability favors the growth of the mesoscale eddies that propagate downstream to the northeastern portion of the well-extended LC, eventually causing the shedding by cutting through the neck of the LC. These upper-layer mesoscale eddies lose their kinetic energy back to the background LC through inverse cascade processes in the neck region. The deep eddies obtain energy primarily from the upper layer through vertical pressure work and secondarily from baroclinic instability in the deep layer. In contrast, the canonical energy transfer between the mesoscale and the high-frequency frontal eddy windows accounts for only a small fraction in the mesoscale eddy energy balance, and this generally acts as a damping mechanism for the mesoscale eddies. A budget analysis reveals that the mesoscale eddy energy gained through the instabilities is balanced by horizontal advection, pressure work, and dissipation.

Hurricane Ian rapidly intensified from Category 3 to 5 as it transited the wide West Florida Shelf (WFS). This is ascribed to heating by the anomalously warm shelf waters, despite the water depth being shallow when compared to the thicker, mixed layer areas of the deeper ocean. By examining temperature from long‐term moorings, we found that the sea surface and subsurface temperatures exceeded the climatologies by 1–2°C and 2–3°C, respectively. Additionally, these anomalously high temperatures in summer/fall of 2022 were related to the absence of Gulf of Mexico Loop Current interactions with the WFS slope at its “pressure point”. Without such offshore forcing to induce an upwelling circulation, the warmer waters on the shelf were not flushed and replaced by colder waters of deeper ocean origin. This work highlights the importance of subsurface temperature and ocean circulation monitoring on shallow continental shelves, which are largely overlooked in hurricane‐related ocean heat content observational programs. Plain Language Summary Rapid intensification of tropical cyclones can be fueled by upper ocean warm water. The favorable environment of high ocean heat potential is thought to be more likely during marine heatwaves. However, both the hurricane heat potential and marine heatwaves are primarily calculated from satellite‐derived sea surface data, with subsurface data largely overlooked due to lack of in situ measurements, particularly in coastal oceans where hurricanes may rapidly intensify before making landfall. Here we examine an unprecedented set of coastal ocean temperature records from long‐term (26 years) moorings on the wide West Florida Shelf for the cause of Hurricane Ian's rapid intensification to a Category 5 hurricane in 2022. We found that while sea surface temperatures exceeded their climatological mean values by 1–2°C in summer/fall of 2022, the subsurface temperature exceedances were even higher (2–3°C). These anomalously warm waters were further ascribed to a lack of a coastal ocean upwelling circulation due to the absence of offshore forcing by the Gulf of Mexico Loop Current. This work highlights the importance of subsurface temperature and current monitoring on shallow continental shelves, which are largely overlooked in hurricane‐related ocean heat content observing programs. Key Points Hurricane Ian (2022) rapidly intensified over a wide continental shelf with subsurface water 2–3°C warmer than climatology The anomalously warm water was related to the absence of Gulf of Mexico Loop Current interactions with the shelf slope Coastal ocean circulation and subsurface temperature monitoring is important for future hurricane intensification forecasts

The paper uses observational data from 1950 to 2014 to investigate rapid intensification (RI) variability of tropical cyclones (TCs) in the North Atlantic and its relationships with large-scale climate variations. RI is defined as a TC intensity increase of at least 15.4 m/s (30 knots) in 24 h. The seasonal RI distribution follows the seasonal TC distribution, with the highest number in September. Although an RI event can occur anywhere over the tropical North Atlantic (TNA), there are three regions of maximum RI occurrence: (1) the western TNA of 12°N–18°N and 60°W–45°W, (2) the Gulf of Mexico and the western Caribbean Sea, and (3) the open ocean southeast and east of Florida. RI events also show a minimum value in the eastern Caribbean Sea north of South America—a place called a hurricane graveyard due to atmospheric divergence and subsidence. On longer time scales, RI displays both interannual and multidecadal variability, but RI does not show a long-term trend due to global warming. The top three climate indices showing high correlations with RI are the June-November ENSO and Atlantic warm pool indices, and the January-March North Atlantic oscillation index. It is found that variabilities of vertical wind shear and TC heat potential are important for TC RI in the hurricane main development region, whereas relative humidity at 500 hPa is the main factor responsible for TC RI in the eastern TNA. However, the large-scale oceanic and atmospheric variables analyzed in this study do not show an important role in TC RI in the Gulf of Mexico and the open ocean southeast and east of Florida. This suggests that other factors such as small-scale changes of oceanic and atmospheric variables or TC internal processes may be responsible for TC RI in these two regions. Additionally, the analyses indicate that large-scale atmospheric and oceanic variables are not critical to TC genesis and formation; however, once a tropical depression forms, large-scale climate variations play a role in TC intensification.

This paper addresses a bias problem in the estimate of wavelet power spectra for atmospheric and oceanic datasets. For a time series comprised of sine waves with the same amplitude at different frequencies the conventionally adopted wavelet method does not produce a spectrum with identical peaks, in contrast to a Fourier analysis. The wavelet power spectrum in this definition, that is, the transform coefficient squared (to within a constant factor), is equivalent to the integration of energy (in physical space) over the influence period (time scale) the series spans. Thus, a physically consistent definition of energy for the wavelet power spectrum should be the transform coefficient squared divided by the scale it associates. Such adjusted wavelet power spectrum results in a substantial improvement in the spectral estimate, allowing for a comparison of the spectral peaks across scales. The improvement is validated with an artificial time series and a real coastal sea level record. Also examined is the previous example of the wavelet analysis of the Niño-3 SST data.

Concurrently operated on the West Florida shelf for the purpose of observing surface currents are three long-range (4.9 MHz) Coastal Ocean Dynamics Applications Radar (CODAR) SeaSonde and two median-range (12.7 MHz) Wellen Radar (WERA) high-frequency (HF) radar systems. These HF radars overlook an array of moored acoustic Doppler current profilers (ADCPs), three of which are presently within the radar footprint. Analyzed herein are 3 months of simultaneous observations. Both the SeaSonde and WERA systems generally agree with the ADCPs to within root-mean-square differences (rmsd) for hourly radial velocity components of 5.1–9.2 and 3.8–6.5 cm s−1 for SeaSonde and WERA, respectively, and within rmsd for 36-h low-pass filtered radial velocity components of 2.8–6.0 and 2.2–4.3 cm s−1 for SeaSonde and WERA, respectively. The bearing offset and tidal and subtidal currents of total velocities are also assessed using the ADCP data. Despite differences in a variety of aspects between the direction-finding CODAR SeaSonde (long range, effective depth of 2.4 m, integration time of 4 h, and idealized antenna patterns) and the beam-forming WERA (median range, effective depth of 0.9 m, and integration time of 1 h), both HF radar systems demonstrated good surface current mapping capability. The differences between the velocities measured with the HF radar and the ADCP are sufficiently small in this low-energy shelf that much of these rmsd values may be accounted for by the expected measurement differences due to the horizontal, vertical, and temporal sampling differences of the ocean current observing systems used.

Hurricane Irma impacted the coastal ocean and estuaries of west Florida as it transited the Florida peninsula from 10 to 12 September 2017, after making landfall first at Cudjoe Key as a Category 4 hurricane and then again at Naples, as a Category 2 hurricane. The response to Hurricane Irma is analyzed using both in situ data and a hindcast simulation by the West Florida Coastal Ocean Model (WFCOM). During the Irma passage, a negative storm surge followed by a positive surge occurred along the west Florida coast, with a recorded water level fluctuation of 3.31 m (from trough to peak) within Rookery Bay, and the negative surge with sea level set-downs (> 1 m) caused drying in Florida Bay and the Charlotte Harbor estuary. Irma-driven currents in Florida Bay, estimated to be 1.50–2.00 m/s, were strong enough to damage benthic communities. The resulting ocean circulation patterns and water exchange pathways are revealed by simulated Lagrangian trajectories. Also investigated is the memory of the coastal system. Whereas sea level and currents restored back to their normal fluctuations within a day, water temperature and salinity required several days to stabilize, and by virtue of heavy rainfall, excess freshwater input from rivers resulted in lower estuarine and nearshore salinities that lasted for several weeks.

Problem solving is sometimes accompanied by a sudden feeling of knowing, or insight . The specific cognitive processes that underlie insightful problem solving are a matter of great interest and debate. Although some investigators favor a special-process view, which explains insight in terms of specialized mechanisms that operate outside of conscious awareness, others favor a business-as-usual account, which posits that insightful problem solving involves the same conscious mechanisms—including working memory (WM) and attention—that are implicated in noninsightful problem solving. In the present study, we used an individual-differences approach to explore the contributions of WM and attention to the solution of compound remote associate (CRA) problems. On the basis of self-report insight ratings, we identified CRA problems whose solution was accompanied by a subjective feeling of insight and examined the correlations between problem performance and measures of WM capacity (verbal and spatial) and attention control (Stroop and antisaccade tasks). The results indicated that individual differences in verbal WM and attention significantly explained variation in overall CRA problem solving and, most importantly, in the occurrence of solutions that were accompanied by a feeling of insight. The findings implicated both modality-dependent WM mechanisms and modality-independent attention control mechanisms in this class of insight problems. Comparisons of the accuracy and solution-latency findings for insightfully versus noninsightfully solved CRA problems, and for participants working silently versus in a “think-aloud” condition, provided additional evidence against the special-process view, and reinforcing the business-as-usual account of insight.