Transient residence and exposure times

[摘要] The residence time measures the time spent by a water parcel or apollutant in a given water body and is therefore widely used inenvironmental studies.The adjoint method introduced by Delhez etal. (2004) to compute thisdiagnostic is revised here to take into account the effect of theinitialization and of the boundary conditions.

In addition to the equation for the mean residence time, it issuggested to solve a simple advection-diffusion problem to quantifythe effect of the initialization and clarify the interpretation ofthe results.

Using the two same equations but with modified boundaryconditions, the method can also be used to quantify theaccumulated time spent by water/tracer parcels in a controldomain.This diagnostic is called "exposure time".

Analytical and realistic model results are used to illustrate theconcepts.

[学科分类] 海洋学与技术