Sea surface temperature fronts in the California Current System from geostationary satellite observations

Abstract

Sea surface temperature (SST) fronts are determined for the 2001–2004 time period from Geostationary Operational Environmental Satellites (GOES) data in the California Current System (CCS). The probability of detecting a SST front at an individual pixel location in the CCS is presented as a bi‐monthly climatology. Fronts clearly indicate the seasonal evolution of coastal upwelling, as well as meanders and filaments that are often linked with irregularities in coastline geometry. Winter is characterized by low frontal activity along the entire coast. Fronts first appear close to the coast during spring, particularly south of Cape Blanco, where upwelling favorable winds are already persistent. The area of high frontal activity continues to increase during summer, especially between Monterey Bay and Cape Blanco, extending more than 300 km from the coast. The region with high frontal activity widens at ∼2.6 km day−1. Off northern Baja California, a band with persistent fronts is found close to the coast year‐round, but there is no evidence of a seasonal widening of the area of higher activity. During fall, the weakening of upwelling favorable winds leads to a gradual decrease in frontal activity. An empirical orthogonal function (EOF) decomposition reveals the development of SST fronts associated with seasonal upwelling for locations north of Monterey Bay, with less summer intensification to the south. The first appearance of fronts close to the coast during spring and the occurrence of the fronts offshore later in the season are represented by additional statistically significant EOF modes.

Shoreward swimming boosts modeled nearshore larval supply and pelagic connectivity in a coastal upwelling region

“…Fronts are associated with phytoplankton blooms and aggregate phytoplankton and larvae, and these phenomena are well-documented in central California (Bjorkstedt et al, 2002;Graham et al, 1992;Ryan et al, 2010Ryan et al, , 2014Traganza and Conrad, 1981;Woodson et al, 2009). Fronts are common and persistent in the CCS (Castelao et al, 2006;Shanks et al, 2003a), and are spatially correlated with higher recruitment of both intertidal and subtidal species . However, fronts may also inhibit recruitment locally by preventing larval-rich water from reaching shore (Galarza et al, 2009;McCulloch and Shanks, 2003).…”

Large-scale movements and high-use areas of western Pacific leatherback turtles,Dermochelys coriacea

“…Both of these CCE foraging areas support seasonal dense aggregations of gelatinous prey, e.g., Chrysaora fuscescens and Aurelia spp., in retention areas created by points, headlands, and frontal regions (Shenker 1984, Graham et al 2001. We identified some additional ARS behavior in offshore waters of central and northern California, where SST fronts are pronounced during the boreal spring and summer in deeper offshore regions (Costelao et al 2006). This area was used by several leatherbacks during early summer prior to arriving in neritic waters and by two leatherbacks tagged in PBI that arrived off California during 2006 when delayed upwelling reduced seasonal productivity (Goericke et al 2007) and jelly prey were scarce (S. R. Benson, unpublished data).…”

NOAA's Sea Surface Temperature Products From Operational Geostationary Satellites

“…Oceanic fronts are an important part of the California Current System (CCS) and are vital to the understanding and management of fisheries within the CCS. A recent paper (Castelao et al 2006) evaluated and used the Oceanic Front Probability Index to study the topographical and seasonal influences on the northern CCS off the coast of Oregon. Specific applications include use in the selection of marine protected areas within the National Marine Sanctuaries, as well as inclusion as a core dataset for the West Coast Regional Associations of the Integrated Ocean Observing System.…”