[en] 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.
Research center :
Centre Interfacultaire de Recherches en Océanologie - MARE - GHER
Disciplines :
Earth sciences & physical geography
Author, co-author :
Rixen, Michel
Allen, J. T.
Pollard, R. T.
Beckers, Jean-Marie ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER)
Language :
English
Title :
Along or across front ocean survey strategy? The estimation of quasi-geostrophic vertical velocities and temperature fluxes
Publication date :
2003
Journal title :
Geophysical Research Letters
ISSN :
0094-8276
eISSN :
1944-8007
Publisher :
American Geophysical Union, Washington, United States - District of Columbia
Allen, J. T., and D. Smeed, Potential vorticity and vertical velocity at the Iceland-Faeroes front, Journal of Physical Oceanography, 26, 2611-2634, 1996.
Allen, J. T., D. Smeed, A. Nurser, J. Zhang, and M. Rixen, Diagnosing vertical velocities using the QG Omega equation: An examination of the errors due to sampling strategy, Deep-Sea Research, 48, 315-346, 2001.
Gomis, D., S. Ruiz, and M. Pedder, Diagnostic analysis of the 3D ageostrophic circulation from a multivariate spatial interpolation of CTD and ADCP data, Deep-Sea Research, 48, 269-295, 2001.
Moore, J. T., and G. E. VanKnowe, The effect of jet-streak curvature on kinematic fields, Monthly Weather Review, 120, 2429-2441, 1992.
Pinardi, N., and J. Woods, Ocean forecasting: Conceptual basis and applications. Springer-Verlag, 2002.
Pollard, R., and L. Regier, Vorticity and vertical circulation at an ocean front, Journal of Physical Oceanography, 22, 609-625, 1992.
Popova, E. E., M. A. Srokosz, and D. A. Smeed, Real-time forecasting of biological and physical dynamics at the Iceland-Faroes Front in June 2001, Geophysical Research Letters, 29(4), 10.1029/2001GL013706, 2001.
Rixen, M., J. T. Allen, and J.-M. Beckers, Diagnosing vertical velocities using the QG omega equation: A relocation method to obtain pseudosynoptic data sets, Deep-Sea Research, 48, 1347-1373, 2001a.
Rixen, M., J. T. Allen, and J.-M. Beckers, Non-synoptic versus pseudosynoptic data sets: An assimilation experiment. In: Three-dimensional ocean circulation: Lagrangian measurements and diagnostic, Journal of Marine Systems, 29, 313-333, 2001b.
Rixen, M., S. Alderson, J. Allen, A. Barth, J.-M. Beckers, V. Cornell, N. Crisp, S. Fielding, A. Mustard, R. Pollard, E. Popova, D. Smeed, and M. Srokosz, Along or across front survey strategy? An operational example at an unstable oceanic front, Geophysical Research Letters, 30(1), doi:10.1029/2002GL015341, 2003.
Rixen, M., and J.-M. Beckers, A synopticity test of sampling pattern in the alboran sea, Journal of Marine Systems, 35, 111-130, 2002.
Robinson, A., A. Hecht, N. Pinardi, J. Bishop, W. Leslie, Y. Rosentraub, A. Mariano, and S. Brenner, Small synoptic/mesoscale eddies: The energetic variability of the Eastern Levantine basin, Nature, 327, 131-134, 1987.
