Observed and modeled meridional overturning circulation related flow into the Caribbean

Abstract

[1] A major pathway of the Atlantic meridional overturning circulation (MOC) is the warm inflow into the Caribbean Sea. The transport and the contribution of water from the South Atlantic is calculated from observations (ADCP data and hydrography) and compared to the results of the 1 12°F LAME model. The model and the observations show high consistency in the strength of the mean total inflow and its range of variability as well as in the general distribution of water from South Atlantic origin. The measurements give an annual mean South Atlantic Water (SAW) transport into the Caribbean of 9.3 Sv with high variability. This estimate has to be regarded as a lower bound since the present method (using temperature and salinity data) cannot identify the SAW included in the North Equatorial Current (NEC), which recirculated and was transformed in the interior tropical Atlantic. The model transport reproduces the observational values rather closely, with an annual mean inflow of 8.6 Sv and similar high variability. Closer inspection of the SAW pathways in the model suggest that the additional contribution by the NEC-pathway is only about 2 Sv. The model results confirm the relative importance of the MOC pathways suggested by observations: the Caribbean inflow seems to be the main pathway (63%) for the warm and central water (s q < 27.1 kg m À3 ), whereas for the intermediate water a larger fraction (59%) is transported northward at the eastern side of the Lesser Antilles.

Atlantic Meridional Overturning Circulation at 14.5° N in 1989 and 2013 and 24.5° N in 1992 and 2015: volume, heat, and freshwater transports

“…1), connecting the Caribbean Sea with the Atlantic. Recent observations combined with a model study suggest that a total flow of 17-19 Sv passes through the Lesser Antilles into the Caribbean Sea (Kirchner et al, 2008), implying that the western boundary current across the 14.5 • N section must recirculate southward across the section in the east, as occurs in both realizations (Fig. 12a, b).…”

On the propagation and decay of North Brazil Current rings

“…The study of Kirchner et al [2008] included a detailed model data comparison, indicating a realistic model behavior with respect to observed mean transports and its variability. Thus, earlier studies validated the model and showed that FLAME is suitable for applications in the tropical North Atlantic.…”

“…[12] The bathymetry in FLAME lacks some detail in the area of complex topography, such as the Lesser Antilles passages (e.g., missing some of the deep parts, see Kirchner et al [2008] for details). The Lesser Antilles are represented as shallow ocean points and are still about 35 m deep.…”

“…[7] The transport into the Caribbean Sea through the various passages of the Lesser Antilles was analyzed by Kirchner et al [2008]. The authors laid their focus especially on the South Atlantic Water fraction of the inflow, which represents an important part of the AMOC.…”

Atlantic meridional overturning circulation at 14.5° N and 24.5° N during 1989/1992 and 2013/2015: volume, heat and freshwater fluxes

“…1), connecting the Caribbean See with the Atlantic. Recent observation and model study suggest that a total flow of 17-19 Sv 30 passes through the Lesser Antilles into the Caribbean Sea (Kirchner et al, 2008), implying that the western boundary current across the 14.5° N section must recirculate southward across the section in the east, as occurs in both realizations (Fig. 12a, b).…”