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Abstract: The South‐Atlantic Patagonian shelf is the largest chlorophyll‐a (Chl‐a) hot spot in Southern Ocean color images. While a persistent 1500 km long band of high Chl‐a along the shelf‐break front (SBF) is indicative of upwelling, the mechanisms that drive it are not entirely known. Along‐front wind oscillations can enhance upwelling and provide a nutrient pumping mechanism at shelf‐break fronts of western boundary currents. Here we assess wind‐induced upwelling at the SBF off Patagonia from daily satellite Chl‐a and winds, historical hydrographic observations, cross‐shelf Chl‐a fluorescence transects from two cruises, and in situ winds and water column structure from a mooring site. Satellite Chl‐a composites segregated by along‐front wind direction indicate that surface Chl‐a is enhanced at the SBF with southerly winds and suppressed with northerly winds. Northerly winds also result in enhanced Chl‐a further offshore (∼25–50 km). Synoptic transects as well as mean hydrographic sections segregated by along‐front winds show isopycnals tilted upward for southerly winds. Spring observations from the mooring also suggest that southerly winds destratify the water column and northerly winds restratify, in agreement with Ekman transport interacting with the front. Moreover, changes in water column temperature lag along‐front wind forcing by 2–4 days. Our results suggest that oscillations in along‐front winds, on timescales typical of atmospheric storms (2–10 days), can significantly modulate the upwelling and Chl‐a concentrations at the SBF off Patagonia, revealing the importance of wind‐induced upwelling for shelf‐slope exchange at shelf‐break fronts of western boundary currents.

The evolution of ocean temperature measurement systems is presented with a focus on the development and accuracy of two critical devices in use today (expendable bathythermographs and conductivity-temperature-depth instruments used on Argo floats). A detailed discussion of the accuracy of these devices and a projection of the future of ocean temperature measurements are provided. The accuracy of ocean temperature measurements is discussed in detail in the context of ocean heat content, Earth's energy imbalance, and thermosteric sea level rise. Up-to-date estimates are provided for these three important quantities. The total energy imbalance at the top of atmosphere is best assessed by taking an inventory of changes in energy storage. The main storage is in the ocean, the latest values of which are presented. Furthermore, despite differences in measurement methods and analysis techniques, multiple studies show that there has been a multidecadal increase in the heat content of both the upper and deep ocean regions, which reflects the impact of anthropogenic warming. With respect to sea level rise, mutually reinforcing information from tide gauges and radar altimetry shows that presently, sea level is rising at approximately 3 mm yr-1 with contributions from both thermal expansion and mass accumulation from ice melt. The latest data for thermal expansion sea level rise are included here and analyzed. Key Points Oceanographic techniques and analysis have improved over many decadesThese improvements allow more accurate Earth-energy balance estimatesUnderstanding of ocean heat content and sea-level rise has also increased ©2013. American Geophysical Union. All Rights Reserved.