Sea surface temperature (SST) anomalies in the Kuroshio Extension (KE) have been suggested to play a crucial role decadal climate variability of North Pacific affecting global and marine ecosystem variability. By analyzing mixed layer heat budget, taking into account seasonality depth (MLD) variations, we here show for first time that KE SST front undergoes large variations mainly owing modulat...

The Humboldt Upwelling System is of global interest due to its importance fisheries, though the origin high productivity remains elusive. In regional physical-biogeochemical model simulations, seasonal amplitude mesozooplankton net production exceeds that phytoplankton, indicating “seasonal trophic amplification.” An analytical approach identifies amplification be driven by a seasonally varying...

A new maximum angle method has been developed to determine surface mixed-layer (a general name for isothermal/constant-density layer) depth from profile data. It has three steps: (1) fitting the profile data with a first vector (pointing downward) from an upper level to a depth and a second vector (pointing downward) from that depth to a deeper level; (2) identifying the angle (varying with dep...

Schematic Skew-T soundings can be used to estimate the depth of elevated mixed layers and their origins thousands of kilometers downstream from their source regions. Focus is on the elevated mixed layer from the Sahara, the Saharan Air Layer (SAL), and its relationship to aerosol optical depth. Aerosol optical depth (AOD) measurements and SAL depth determined from atmospheric soundings were tab...

The onset of phytoplankton blooms in late winter, early spring has been traditionally associated with the shoaling of the mixed layer above a critical depth. Here we show that the onset of a bloom can also be triggered by a reduction in air-sea fluxes at the end of winter. When net cooling subsides at the end of winter, turbulent mixing becomes weak, thereby increasing the residence time of phy...