Along or across front ocean survey strategy? The estimation of quasi-geostrophic vertical velocities and temperature fluxes

• Published in: Geophysical Research Letters
• Main Authors: Rixen, Michel, Allen, J. T., Pollard, R. T., Beckers, Jean-Marie
• Other Authors: Centre Interfacultaire de Recherches en Océanologie - MARE - GHER
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2003
• Subjects: Atlantic Ocean Islands; Iceland; Temperature; Oceanic front; Vertical speed; Mesoscale; Sampling; Omega equation; Models; Quasi geostrophic approximation; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Faroes
• Online Access: https://orbi.uliege.be/handle/2268/73989; https://doi.org/10.1029/2002GL015810

peer reviewed In a companion paper we have shown that at the mesoscale, the unusual across front sampling strategy (AL) is more accurate than the usual across front sampling strategy (AC) on hydrographic and bio-chemical properties when the front is sufficiently developed. The cruise design based on the optimal reconstruction of the density fields does however not imply that derived variables like quasi-geostrophic (QG) vertical velocities and temperature fluxes also exhibit minimal associated errors. Here we present results of optimized sampling strategies for diagnostic QG vertical velocities (wQG) and temperature fluxes (θQG) derived from the omega equation. Results are illustrated in the same framework, for the Iceland-Faroes oceanic frontal area and for a control model and reveal that at these spatio-temporal scales, the unusual AL may also provide better estimations of vertical velocities and temperature fluxes compared to the classic AC, especially when the front is sufficiently developed.