Scatterometer and ECMWF‐derived wind vorticity over the Mediterranean Basin
Authors: Zecchetto S. , De Biasio F. , Accadia C. 
Published: August 2012

This article investigates the spatial and temporal structures of the monthly mean vorticity fields \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} and \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document} over the Mediterranean Basin, derived respectively from satellite scatterometers and ECMWF global atmospheric model (T799) wind fields from February 2006 to January 2010. Statistics show a mean difference between \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} and \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document} over the whole Mediterranean Sea (relative bias \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\Delta \overline{\omega}}$ \end{document}) of 0.108×10−5 s−1. Furthermore, both the cyclonic and the anticyclonic components of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} are stronger than those of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document}. The analysis of the spatial features of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} and \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document} shows that the greatest discrepancies occur along coasts and in the Adriatic Sea, due to the ability of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} to describe vorticity features smaller than about 6.9×103 km2, roughly corresponding to square areas of side 83 km or circular areas of radius 46 km, that are not present in \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document}, given the effective spatial resolution of the model. The temporal features of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} and \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document} have shown a substantially similar trend in anticyclonic and a deep difference in cyclonic circulations, again related to the limited ability of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document} to describe small‐scale vorticity patches as the main source of the differences. Local characterization of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} and \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document}, along six transects across areas where the wind vorticity features are well known, has confirmed the results of substantial similarity of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm sc}}$ \end{document} and \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\boldsymbol{\overline{\omega}^{\rm e}}$ \end{document} at spatial scales larger than 100 km or so and remarkable differences in those regions, such as the Adriatic and Crete seas, affected by vorticity variability at smaller scales. Copyright © 2012 Royal Meteorological Society