Recent changes in the surface salinity of the North Atlantic subpolar gyre

Sea surface salinity (SSS) was measured since 1896 along 60°N between Greenland and the North Sea and since 1993 between Iceland and Newfoundland. Along 60°N away from the shelves, and north of 53°N, the amplitude of the seasonal cycle is comparable to or less than interannual variability. In these parts of the North Atlantic subpolar gyre, large-scale deviations from the seasonal cycle correlate from one season to the next. This suggests that in these regions, summer and autumn surface data are useful for monitoring changes in upper ocean salinity best diagnosed from less common winter surface data. Further south near the subarctic front, the Labrador Current or near shelves where seasonal variability is strong, this is not the case. Along 60°N, the multiannual low-frequency variability is well correlated across the basin and exhibits fresher surface water since the mid 1970s than in the late 1920s to 1960s. SSS in the Irminger Sea along 60°N lags by 1-year SSS farther east in the Iceland Basin. Variability between Iceland and Newfoundland within the Irminger Sea north of 54°N presents similar characteristics to what is observed along 60°N. Variability near the northwest corner of the North Atlantic Current (52°N/45°W) is larger and is not correlated to what is found further north. Maps of SSS were constructed for a few recent seasons between July 1996 and June 2000, which illustrate the fresh conditions found usually during that period across the whole North Atlantic subpolar gyre, although this includes an episode of higher salinity. The SSS anomaly maps have large uncertainties but suggest that the highest SSS occurred before the spring of 1998 in the Iceland Basin, and after that, in the Irminger Sea. This is followed by fresher conditions, first in the Labrador and Iceland Basin, reaching recently the Irminger Sea

Modeled surface dynamic height in 1964-1984 : an effort to assess how well the low frequencies in the Equatorial Atlantic were sampled in 1982-1984

A wind-forced linear model has been used to produce 21 years (1964--1984) of monthly time series of surface dynamic height in the Equatorial Atlantic. Theclimatological seasonal cycle is substracted, and the statistical characteristics of the residuals are analyzed. An empirical orthogonal function analysis reveals that the most significant pattern has deviations of one sign in the Western Equatorial Atlantic. The anomalies in the last 2 years, 1983 and 1984, are particularly large. The time component of the first empirical orthogonal function peaks in july 1983, changes sign at the end of 1983, and has an extremun of the opposite sign in April 1984. At that time, the zonal slope of dynamic height had reversed with respect to normal along the equator. (D'aprèsrésumé d'auteur

Thyrotoxicosis-facilitated bridge to recovery with a continuous-flow left ventricular assist device

The HeartMate II is a continuous-flow left ventricular assist device that can be explanted from patients after cardiac recovery. We implanted a HeartMate II in a 21-year-old man who had idiopathic cardiomyopathy. A year later, he developed thyrotoxicosis, presumably secondary to amiodarone administered for ventricular fibrillation. Four months after the diagnosis of thyrotoxicosis, thyroid hormone levels had returned to normal, and native cardiac function had improved remarkably. After a support period of 24 months, the HeartMate II was explanted. Six years later, the patient continues to be in New York Heart Association functional Class I. Amiodarone-induced thyrotoxicosis may have contributed to myocardial recover

Surface Salinity in the North Atlantic subtropical gyre: During the STRASSE/SPURS Summer 2012 Cruise

Reverdin, Gilles ... et. al.-- Special issue on SPURS: Salinity Processes in the Upper-ocean Regional Study.-- 10 pages, 7 figuresWe investigated a 100 × 100 km high-salinity region of the North Atlantic subtropical gyre during the Sub-Tropical Atlantic Surface Salinity Experiment/Salinity Processes in the Upper-ocean Regional Study (STRASSE/SPURS) cruise from August 21, 2012, to September 9, 2012. Results showed great variability in sea surface salinity (SSS; over 0.3 psu) in the mesoscale, over 7 cm of total evaporation, and little diapycnal mixing below 36 m depth, the deepest mixed layers encountered. Strong currents in the southwestern part of the domain, and the penetration of freshwater, suggest that advection contributed greatly to salinity evolution. However, it was further observed that a smaller cyclonic structure tucked between the high SSS band and the strongest currents contributed to the transport of high SSS water along a narrow front. Cross-frontal transport by mixing is also a possible cause of summertime reduction of SSS. The observed structure was also responsible for significant southward salt transport over more than 200 km. © 2015 by The Oceanography Society. All rights reservedThis effort was supported nationally in France by CNES/TOSCA with the Gloscal and SMOS projects and by LEFE/INSU for the STRASSE/SPURS project, in Spain at ICM/CSIC by the Spanish national R+D plan (project AYA2010-22062-C05). The cruise took place on board R/V Thalassa owned by IFREMER and operated by GENAVIR. Support from the ship’s captain and crew during the STRASSE cruise is gratefully acknowledged. Some French instruments were also funded by INSU and IFREMER, and the trimaran platform Ocarina was also partially funded by IPSL. Nicolas Kolodziejczyk’s postdoctoral fellowship was awarded by CNES. Support for ASIP work is from the Office of Naval Research under Award No. N62909-12-1-7064, and Graig Sutherland’s scholarship PGSD3-410251-258 2011 was awarded by the National Research Council of Canada. SVP drifters were provided by the Global Drifter Program, NOAA grant #NA10OAR432056. LC and VH were supported by NASA grant #NNX12AI67G and NOAA grant #NA10OAR432056Peer Reviewe

Vertical structure of the seasonal cycle in the Central Equatorial Atlantic ocean : XBT sections from 1980 to 1988

A set of temperature profiles from expendable bathythermographs collected from 1980 to april 1988 along two ship routes transecting the Equatorial Atlantic from 11°N to 11°S is analyzed to infer the vertical structure of the annual variability of the temperature and the currents in the upper ocean. During the average seasonal cycle, the vertical isotherm displacements occur earlier below 300 meters than near the surface at most locations within 4 degrees of the equator. At the equator the amplitude of the displacements does not decrease with depth in the upper 500 meters. This still holds down to 700 meters, but there are less data at these depths. The lead of the deeper isotherm displacements with respect to those in the upper thermocline implies that there is a contribution to the pressure forces from these layers that is not in phase with the contribution of the upper thermocline. This also suggests that the energy source of the seasonal variability is close to the surface. Dynamic height and geostrophic current relative to 400 db are also estimated. A seasonal cycle is found on the subsurface currents, which vary by up to a factor two during the cycle. (Résumé d'auteur

Study of the potential for existing bathythermic string drifters

Evaluation report on the use of subsurface temperature buoy data and on their ability to provide suitable measurements in the ocean boundary laye