scholarly journals Seasonal mixed-layer salinity balance in the tropical Atlantic Ocean: Mean state and seasonal cycle

2013 ◽  
Vol 118 (1) ◽  
pp. 332-345 ◽  
Author(s):  
C. Y. Da-Allada ◽  
G. Alory ◽  
Y. du Penhoat ◽  
E. Kestenare ◽  
F. Durand ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Mixed Layer ◽  
Seasonal Cycle ◽  
Tropical Atlantic ◽  
Tropical Atlantic Ocean ◽  
Salinity Balance ◽  
Mean State

scholarly journals Modelling the vertical distribution of bromoform in the upper water column of the tropical Atlantic Ocean

2009 ◽  
Vol 6 (4) ◽  
pp. 535-544 ◽  
Author(s):  
I. Hense ◽  
B. Quack
Keyword(s):  
Atlantic Ocean ◽  
Water Column ◽  
Mixed Layer ◽  
Surface Mixed Layer ◽  
Tropical Atlantic ◽  
Tropical Atlantic Ocean ◽  
Subsurface Maximum ◽  
The Vertical Distribution ◽  
Production Layer ◽  
Inverse Proportionality

Abstract. The relative importance of potential source and sink terms for bromoform (CHBr3) in the tropical Atlantic Ocean is investigated with a coupled physical-biogeochemical water column model. Bromoform production is either assumed to be linked to primary production or to phytoplankton losses; bromoform decay is treated as light dependent (photolysis), and in addition either vertically uniform, proportional to remineralisation or to nitrification. All experiments lead to the observed subsurface maximum of bromoform, corresponding to the subsurface phytoplankton biomass maximum. In the surface mixed layer, the concentration is set by entrainment from below, photolysis in the upper few meters and the outgassing to the atmosphere. The assumed bromoform production mechanism has only minor effects on the solution, but the various loss terms lead to significantly different bromoform concentrations below 200 m depth. The best agreement with observations is obtained when the bromoform decay is coupled to nitrification (parameterised by an inverse proportionality to the light field). Our model results reveal a pronounced seasonal cycle of bromoform outgassing, with a minimum in summer and a maximum in early winter, when the deepening surface mixed layer reaches down into the bromoform production layer.

scholarly journals Simulation of the seasonal cycle in the Tropical Atlantic Ocean

1984 ◽  
Vol 11 (8) ◽  
pp. 802-804 ◽  
Author(s):  
S. G. H. Philander ◽  
R. C. Pacanowski
Keyword(s):  
Atlantic Ocean ◽  
Seasonal Cycle ◽  
Tropical Atlantic ◽  
Tropical Atlantic Ocean

scholarly journals Contribution of the Amazon River Discharge to Regional Sea Level in the Tropical Atlantic Ocean

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2348 ◽  
Author(s):  
Pierrick Giffard ◽  
William Llovel ◽  
Julien Jouanno ◽  
Guillaume Morvan ◽  
Bertrand Decharme
Keyword(s):  
Atlantic Ocean ◽  
Interannual Variability ◽  
Sea Level ◽  
River Discharge ◽  
River Mouth ◽  
Amazon River ◽  
Tropical Atlantic ◽  
Tropical Atlantic Ocean ◽  
Seasonal And Interannual Variability ◽  
Mean State

The Amazon River is by far the largest river by volume of water in the world, representing around 17% of the global riverine discharge to the oceans. Recent studies suggested that its impact on sea level is potentially important at global and regional scales. This study uses a set of regional simulations based on the ocean model NEMO to quantify the influence of the Amazon runoff on sea level in the Tropical Atlantic Ocean. The model is forced at its boundaries with daily fields from the ocean reanalysis GLORYS2V4. Air-sea fluxes are computed using atmospheric variables from DFS5.2, which is a bias-corrected version of ERAinterim reanalysis. The particularity of this study is that interannual daily runoffs from the up-to-date ISBA-CTRIP land surface model are used. Firstly, mean state of sea level is investigated through a comparison between a simulation with an interannual river discharge and a simulation without any Amazon runoff. Then, the impact of the Amazon River on seasonal and interannual variability of sea level is examined. It was shown that the Amazon River has a local contribution to the mean state sea level at the river mouth but also a remote contribution of 3.3 cm around the whole Caribbean Archipelago, a region threatened by the actual sea level rise. This effect is mostly due to a halosteric sea level contribution for the upper 250 m of the ocean. This occurs in response to the large scale advection of the plume and the downward mixing of subsurface waters at winter time. The Amazon discharge also induces an indirect thermosteric sea level contribution. However, this contribution is of second order and tends to counterbalance the halosteric sea level contribution. Regional mass redistributions are also observed and consist in a 8 cm decrease of the sea level at the river mouth and a 4.5 increases on continental shelves of the Gulf of Mexico and Caribbean Sea. In terms of variability, simulations indicate that the Amazon discharge may contributes to 23% and 12% of the seasonal and interannual sea level variances in the Caribbean Archipelago area. These variances are first explained by the Amazon time mean discharge and show very weak sensitivity to the seasonal and interannual variability of the Amazon runoff.

scholarly journals Modelling the vertical distribution of bromoform in the upper water column of the tropical Atlantic Ocean

2008 ◽  
Vol 5 (6) ◽  
pp. 4919-4944 ◽  
Author(s):  
I. Hense ◽  
B. Quack
Keyword(s):  
Atlantic Ocean ◽  
Water Column ◽  
Mixed Layer ◽  
Surface Mixed Layer ◽  
Tropical Atlantic ◽  
Tropical Atlantic Ocean ◽  
Subsurface Maximum ◽  
The Vertical Distribution ◽  
Production Layer ◽  
Inverse Proportionality

Abstract. The relative importance of potential source and sink terms for bromoform (CHBr3) in the tropical Atlantic Ocean is investigated with a coupled physical-biogeochemical water column model. Bromoform production is either assumed to be linked to primary production or to phytoplankton losses; bromoform decay is treated as light dependent (photolysis), and in addition either vertically uniform, proportional to remineralisation or to nitrification. All experiments lead to the observed subsurface maximum of bromoform, corresponding to the subsurface phytoplankton biomass maximum. In the surface mixed layer, the concentration is set by entrainment from below, photolysis in the upper few meters and the outgassing to the atmosphere. The assumed bromoform production mechanism has only minor effects on the solution, but the various loss terms lead to significantly different bromoform concentrations below 200 m depth. The best agreement with observations is obtained when the bromoform decay is coupled to nitrification (parameterised by an inverse proportionality to the light field). Our model results reveal a pronounced seasonal cycle of bromoform outgassing, with a minimum in summer and a maximum in early winter, when the deepening surface mixed layer reaches down into the bromoform production layer.

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