F. Hernandez et al., OPTIMIZING A DRIFTER CAST STRATEGY WITH A GENETIC ALGORITHM, Journal of atmospheric and oceanic technology, 12(2), 1995, pp. 330-345
An experiment design problem-that of drifter cast strategy-is discusse
d. Different optimization techniques used as part of preparations for
the Semaphore-93 air-sea experiment, during which drifters were deploy
ed, are examined. The oceanographic experiment objective was to sample
a 500-km-square zone centered at 33 degrees N, 22 degrees W in the Az
ores current area, using an average of 25 surface drifters for at leas
t one month. We investigate different ''orders of merit'' for determin
ing the performance of a particular cast strategy, as well as the meth
od of genetic algorithms for optimizing the strategy. Our technique us
es dynamic reference knowledge of the area where the simulation takes
place. Two reference sets were used: a steady-state field calculated w
ith data collected from the Kiel University April 1982 hydrographic ex
periment, and data output from a regional quasigeostrophic model assim
ilating two years of Geosat altimetric data. The strategies obtained v
ia the genetic algorithm method were compared with regular array drift
er deployments, which is the intuitive and commonly used approach. It
was also found that a cheap objective function gives strategies compar
able to one which was more accurate but computationally expensive. Opt
imization by the genetic algorithm method is shown to be efficient and
robust.