10. Owing to the similarity in the ambient conditions and comparable
parameters at the simulated overflow, the shape of the θ-S curve and the magnitude of the temperature maximum are in good agreement with this generalisation. The results in this section expand on the Rudels and Quadfasel, 1991 schematic and describe the response in the mixing to variations in volume transport at the sill (see Fig. 8(b)). The maximum bottom temperature along the plume path is mainly a function of the flow rate (see Fig. 9(a)). The depth at which the temperature maximum occurs, on the other hand, is mainly a function of the inflow salinity. To explain these results we consider the processes and factors affecting the temperature maximum on the slope: (i) downslope advection of AW by the plume, (ii) Selleckchem DAPT the plume’s momentum arising from its density gradient, (iii) mixing of the plume with Atlantic Water, (iv) the smallness of the thermal expansion coefficient at low temperatures, and (v) the total thermal capacity of the plume water. In the following, we investigate how the salinity S and flow rate Q of the dense water inflow affect the plume’s final depth level. We quantify the downslope penetration of SFOW by calculating how much passive tracer (PTRC) is resident within a given www.selleckchem.com/products/i-bet-762.html depth range by the end of the model run. The concentration of tracer is integrated over a given volume to give the mass of PTRC, MPTRCMPTRC.
Astemizole The penetration of the cascade into a given depth range is calculated as a percentage of MPTRCMPTRC within the given range compared to the total MPTRCMPTRC over the entire domain. A model run and its dense water supply can then be characterised according to the depth range containing more than 50% of PTRC that has been injected over 90 days. In Fig. 11 we plot the results against S and Q for each of the 45 model runs. The final tracer percentage
present within the given depth range is shaded in a contour plot where the S-Q combination of each experiment is marked by a black dot. In those model runs where the majority of PTRC is present between 500 and 1000 m at the end of the experiment the plume has intruded into the Atlantic Layer and into the AW-NSDW interface, but not retained a strong enough density contrast to flow deeper. The combinations of S and Q producing this result are emphasised in Fig. 11(a) as the dots within the red shading indicating a tracer penetration greater than 50%. In the S-Q parameter space these runs are arranged in a curved band from low-S/high-Q via medium-S/medium-Q towards high-S/low-Q. In runs with lower S/lower Q (towards the lower left corner of the graph) the majority of the plume waters is trapped at shallower depths. In experiments with higher S/higher Q (towards the upper right corner of the graph) the plume reaches deeper as shown in Fig. 11(b) which is plotted for the presence of PTRC below 1000 m. Fig.