Along or across front survey strategy? An operational example at an unstable front

• Published in: Geophysical Research Letters
• Main Authors: Rixen, Michel, Allen, J. T., Alderson, S., Cornell, V., Crisp, N., Fielding, S., Mustard, A. T., Pollard, R. T., Popova, E. E., Smeed, D. A., Srokosz, M. A., Barth, Alexander, Beckers, Jean-Marie
• Other Authors: Centre Interfacultaire de Recherches en Océanologie - MARE - GHER
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2003
• Subjects: Ocean prediction; Eddies and mesoscale processes; Fronts and jets; Modeling; Physical; chemical; mathematical & earth Sciences; Physique; chimie; mathématiques & sciences de la terre; Faroes; Iceland
• Online Access: https://orbi.uliege.be/handle/2268/74185; https://doi.org/10.1029/2002GL015341

peer reviewed [1] We present results of the optimization of near-real time on-board sampling strategy in the Iceland-Faroes oceanic frontal area, based on the outputs of a mesoscale 3D operational data assimilation forecasting experiment. By minimizing a root mean square error cost function, we show that in this example an along-front sampling strategy, i.e. with transects parallel to the front, produces smaller errors in temperature, salinity, nitrate, phytoplankton, and zooplankton fields, as a result of a combination of the direction of the sampling of the front and errors associated with the asynopticy of observations (Doppler effect). This is contrary to the classic across-front sampling strategies that are used in most field experiments reported in the literature, i.e. where transects are perpendicular to the front. A control model shows that at these spatio-temporal scales, the along front sampling strategy is optimal when the frontal instability has sufficiently developed.