IMIS | Flanders Marine Institute

Flanders Marine Institute

Platform for marine research


Publications | Institutes | Persons | Datasets | Projects | Maps
[ report an error in this record ]basket (0): add | show Print this page

The residence time of settling particles in the surface mixed layer
Deleersnijder, E.; Beckers, J.-M.; Delhez, E.J.M. (2006). The residence time of settling particles in the surface mixed layer. Environ. Fluid Mech. 6(1): 25-42.
In: Environmental Fluid Mechanics. Springer: London; Dordrecht; Boston. ISSN 1567-7419; e-ISSN 1573-1510, more
Peer reviewed article  

Available in  Authors 
    VLIZ: Open Repository 103866 [ OMA ]

    Layers > Discontinuity layers > Pycnocline
    Layers > Water column > Mixed layer
    Residence time
Author keywords
    adjoint model; mixed layer; pycnocline; residence time; settling

Authors  Top 
  • Deleersnijder, E., more
  • Beckers, J.-M., more
  • Delhez, E.J.M., more

    The transport from the upper mixed layer into the pycnocline of particles with negative buoyancy is considered. Assuming the hydrodynamic parameters to be time- independent, an adjoint model is resorted to that provides a general expression of the residence time in the mixed layer of the constituent under study. It is seen that the residence time decreases as the settling velocity increases or the diffusivity decreases. Furthermore, it is demonstrated that the residence time must be larger than z/w and smaller than h/w, where z, h and w denote the distance to the pycnocline, the thickness of the mixed layer and the sinking velocity. In the vicinity of the pycnocline, the residence time is not necessarily zero; its behaviour critically depends on the eddy diffusivity profile in this region. Closed-form solutions are obtained for constant and quadratic diffusivity profiles, which allows for an analysis of the sensitivity of the residence time to the Peclet number. Finally, an approximate value is suggested of the depth-averaged value of the residence time.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors