Submesoscale and Mesoscale Eddies in the Florida Straits: Observations from Satellite Ocean Color Measurements

Abstract

Despite their well‐recognized importance in driving ocean physics and biology, submesoscale (diameter < Rossby radius of deformation) eddies have been extremely difficult to observe due to technical difficulties from both field and remote platforms. Here using novel satellite ocean color data products and modified algorithms, we address this challenge for the Florida Straits (22–28°N, 78–85°W). Between 2002 and 2018, while mesoscale eddies (radius >15 km) show strong seasonality with occurrence frequency decreasing from Lower Keys to Upper Keys, submesoscale eddies show little or no seasonality with high occurrence frequency restricted to 30–200‐m isobaths. The number of mesoscale eddies decreases exponentially in size, but submesoscale eddies show a normal distribution in size. These findings are significant in filling our knowledge gap in submesoscale eddies in this physically and ecologically important region as it encompasses world‐renowned coral reefs, seagrasses, and fisheries.

Ocean Temperature and Color Frontal Zones in the Gulf of Mexico: Where, When, and Why

“…Of these, the gradient‐based method is characterized by its simplicity (e.g., Breaker et al., 2005; Kostianoy et al., 2004). The widely used Canny edge detection method (Canny, 1986; Castelao & Wang, 2014; Castelao et al., 2006; Jones et al., 2012; Wall et al., 2008; Wang et al., 2015; Zhang et al., 2019) and the Belkin & O’Reilly algorithm (BOA, Belkin & O'Reilly, 2009; Dodge et al., 2014; Guo et al., 2017; Lin et al., 2019; Liu & Hou, 2012; Liu et al., 2018; Oh et al., 2020; Sagarminaga & Arrizabalaga, 2014; Wei et al., 2020; Woodson et al., 2012; Zeng et al., 2014) are classified as gradient‐based methods. The histogram method is characterized by its robustness and worldwide validation (e.g., Belkin et al., 2009; Cayula &Cornillon, 1992, 1995, 1996; Kahru et al., 2012, 2018; Svendsen et al., 2020; Tseng et al., 2014; Ullman & Cornillon, 1999, 2000, 2001; Wall et al., 2008).…”

DNA barcoding of fish eggs collected off northwestern Cuba and across the Florida Straits demonstrates egg transport by mesoscale eddies

“…In addition to the fast‐moving Florida Current, both mesoscale and sub‐mesoscale eddies frequently occur in the area (Kourafalou & Kang, 2012; Lee, Leaman, Williams, Berger, & Atkinson, 1995; Shay, Lee, Williams, Graber, & Rooth, 1998). Based on long‐term satellite ocean color measurements, Zhang, Hu, Liu, Weisberg, and Kourafalou (2019) revealed strong seasonality of mesoscale cyclonic eddy occurrence in the Florida Straits with the highest occurrence in the summer and lowest occurrence in the winter. These cyclonic eddies are highly productive ecosystems that are rich in nutrients, phytoplankton, and copepods (Hitchcock et al., 2005; Lee, Clarke, Williams, Szmant, & Berger, 1994) and can influence cross‐shelf transport of fish larvae (Lane, Smith, Graber, & Hitchcock, 2003; Lee et al., 1992; Limouzy‐Paris, Graber, Jones, Röpke, & Richards, 1997; Shulzitski, Sponaugle, Hauff, Walter, & Cowen, 2016; Shulzitski et al., 2017; Sponaugle, Lee, Kourafalou, & Pinkard, 2005).…”

Sun glint correction with an inherent optical properties data processing system

“…Because many ocean colour instruments cannot tilt their sensors away from nadir, the ocean colour images acquired by those instruments are likely to be severely contaminated by sun glint. Sun glint can cause > 30% of total nonzero images to be discarded, which is a disadvantage to visually estimating real-time physical and chemical processes in the open ocean such as small-scale eddies and circulation (Zhang et al 2019). The original IDAS algorithm corrects residual error in satellite R rs associated with imperfect data processing procedures.…”