| 1. |
- Aldama Campino, Aitor, et al.
(författare)
-
Meridional Ocean Carbon Transport
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The ocean's ability to take up and store CO$_{2}$ is a key factor for understanding past and future climate variability. However, qualitative and quantitative understanding of surface-to-interior pathways, and how the ocean circulation affects the CO$_2$ uptake, is limited. Consequently, how changes in ocean circulation may influence carbon uptake and storage and therefore the future climate remains ambiguous.Here we quantify the roles played by ocean circulation and various water masses in the meridional redistribution of carbon.We do so by calculating stream functions defined in Dissolved Inorganic Carbon (DIC) and latitude coordinates, using output from a coupled biogeochemical-physical model. By further separating DIC into components originating from the solubility pump and a residual including the biological pump, air-sea disequilibrium and anthropogenic CO$_2$, we are able to distinguish the dominant pathways of how carbon enters particular water masses.With this new tool, we show that the largest meridional carbon transport occurs in a pole-to-equator transport in the subtropical gyres in the upper ocean. We are able to show that this pole-to-equator DIC transport, and the Atlantic Meridional Overturning Circulation (AMOC) related DIC transport, are mainly driven by the solubility pump. By contrast, the DIC transport associated with deep circulation, including that in Antarctic Bottom Water and Pacific Deep Water, is mostly driven by the biological pump. As these two pumps, as well as ocean circulation, are widely expected to be impacted by anthropogenic changes, these findings have implications for the future role of the ocean as a climate-buffering carbon reservoir.
|
|
| 2. |
- Aldama-Campino, Aitor, et al.
(författare)
-
Meridional Ocean Carbon Transport
- 2020
-
Ingår i: Global Biogeochemical Cycles. - 0886-6236 .- 1944-9224. ; 34:9
-
Tidskriftsartikel (refereegranskat)abstract
- The ocean's ability to take up and store CO2 is a key factor for understanding past and future climate variability. However, qualitative and quantitative understanding of surface‐to‐interior pathways, and how the ocean circulation affects the CO2 uptake, is limited. Consequently, how changes in ocean circulation may influence carbon uptake and storage and therefore the future climate remains ambiguous. Here we quantify the roles played by ocean circulation and various water masses in the meridional redistribution of carbon. We do so by calculating streamfunctions defined in dissolved inorganic carbon (DIC) and latitude coordinates, using output from a coupled biogeochemical‐physical model. By further separating DIC into components originating from the solubility pump and a residual including the biological pump, air‐sea disequilibrium, and anthropogenic CO2, we are able to distinguish the dominant pathways of how carbon enters particular water masses. With this new tool, we show that the largest meridional carbon transport occurs in a pole‐to‐equator transport in the subtropical gyres in the upper ocean. We are able to show that this pole‐to‐equator DIC transport and the Atlantic meridional overturning circulation (AMOC)‐related DIC transport are mainly driven by the solubility pump. By contrast, the DIC transport associated with deep circulation, including that in Antarctic bottom water and Pacific deep water, is mostly driven by the biological pump. As these two pumps, as well as ocean circulation, are widely expected to be impacted by anthropogenic changes, these findings have implications for the future role of the ocean as a climate‐buffering carbon reservoir.
|
|
| 3. |
- Berglund, Sara, 1990-, et al.
(författare)
-
North Atlantic Ocean Circulation and Related Exchange of Heat and Salt Between Water Masses
- 2023
-
Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 50:13
-
Tidskriftsartikel (refereegranskat)abstract
- The meridional transport of mass, heat, and salt in the North Atlantic Ocean is often described for separate regions and parts, but rarely are all components of the circulation followed at once. Lagrangian trajectories have here been used to divide the North Atlantic Ocean circulation into four different pathways. In the boundary between the Subpolar and Subtropical Gyres, we show that the northward flowing waters exchange heat and salt with the water originating from the subpolar regions. This subsurface water mass exchange takes place in the first 1,000 m and is a key piece of the puzzle of how the Atlantic Meridional Overturning Circulation transports heat and salt. Between 30 & DEG; and 60 & DEG;N the northward flowing water loses 8.8 Gg/s salt to the Subpolar Gyre and an equivalent loss of only 1.7 Gg/s to the atmosphere due to the net fresh water influx.
|
|
| 4. |
- Berglund, Sara, et al.
(författare)
-
The contrasting roles of heat and salt in the overturning circulation of the North Atlantic Ocean
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The meridional transport of mass, heat and salt in the North Atlantic Ocean is often described for separate regions and parts, but rarely are all components of the circulation followed in the same study. In the present study we use Lagrangian trajectories to divide the North Atlantic Ocean Circulation into four different pathways, all contributing to the total circulation and its appurtenant heat and salt changes. In the boundary between the Subpolar and Subtropical Gyres, we show that the northward flowing waters in the North Atlantic Ocean lose heat and salt through exchange with the water originating from the subpolar North Atlantic Ocean. This in turn means that the subpolar waters gain this amounts of heat and salt.Water leaving the subpolar region as North Atlantic Deep Water are clearly distinguishable from this subpolar water, both geographically and in temperature and salinity. The southward flowing North Atlantic Deep Water meets the colder and fresher Antarctic Bottom Water in the interior, where they exchange heat and salt before returning southwards as a unified flow. The separation of the overturning circulation by Lagrangian trajectories thus reveals how the components of the North Atlantic Ocean Circulation exchange heat and salt and thus have contrasting roles.
|
|
| 5. |
- Berglund, Sara, et al.
(författare)
-
The Downward Spiralling Nature of the North Atlantic Subtropical Gyre
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The Atlantic Meridional Overturning Circulation (AMOC) regulates the heat distribution and climate of Earth. Here we identify a new feature of the circulation within the North Atlantic Subtropical Gyre that is associated with the northward flowing component of the AMOC.We find that 70% of the water that flows northwards as part of the AMOC circulates the Gyre at least once before it can continue northwards.These circuits are needed to achieve an increase of density and depth through a combination of air-sea interaction and interior mixing processes, before water can escape the latitudes of the Gyre and join the northern upper branch of the AMOC.This points towards an important role of the Gyre circulations in determining the strength and variability of the AMOC and the northward heat transport.Understanding this newly identified role of the North Atlantic Subtropical Gyre is needed to properly represent future changes of the AMOC.
|
|
| 6. |
- Berglund, Sara, 1990-, et al.
(författare)
-
The downward spiralling nature of the North Atlantic Subtropical Gyre
- 2022
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- The Atlantic Meridional Overturning Circulation (AMOC) regulates the heat distribution and climate of Earth. Here we identify a new feature of the circulation within the North Atlantic Subtropical Gyre that is associated with the northward flowing component of the AMOC. We find that 70% of the water that flows northwards as part of the AMOC circulates the Gyre at least once before it can continue northwards. These circuits are needed to achieve an increase of density and depth through a combination of air-sea interaction and interior mixing processes, before water can escape the latitudes of the Gyre and join the northern upper branch of the AMOC. This points towards an important role of the Gyre circulation in determining the strength and variability of the AMOC and the northward heat transport. Understanding this newly identified role of the North Atlantic Subtropical Gyre is needed to properly represent future changes of the AMOC.
|
|
