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Original Research Papers

On statistics of the free-troposphere synoptic component: an evaluation of skewnesses and mixed third-order moments contribution to the synoptic-scale dynamics and fluxes of heat and humidity

Authors:

Vladimir Petoukhov ,

Potsdam Institute for Climate Impact Research, A26 Telegrafenberg, 14473 Potsdam, DE
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Alexey V. Eliseev,

A.M. Obukhov Institute of Atmospheric Physics RAS, 3 Pyzhevsky, 119017 Moscow, RU
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Rupert Klein,

Potsdam Institute for Climate Impact Research, A26 Telegrafenberg, 14473 Potsdam, DE
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Hermann Oesterle

Potsdam Institute for Climate Impact Research, A26 Telegrafenberg, 14473 Potsdam, DE
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Abstract

Based on the ERA40 data for 1976-2002 we calculated skewnesses and mixed third-order statistical moments (TOMs) for the synoptic variations [with (2.5-6) d timescales] of horizontal winds, temperature, vertical velocity and the specific humidity in Eulerian coordinates. All these variables show skewnesses which markedly deviate from zero, basically at the entries and the outlets of the mid-latitude storm tracks. In these regions, high values of skewness for vertical velocity, temperature and the specific humidity are revealed throughout the entire free troposphere, while the marked skewnesses for horizontal winds are traced in the lower free troposphere. We found a notable deviation of the synoptic-component statistics from the Gaussian statistics. We also made an estimate of the contribution from TOMs to the prognostic equations for the synoptic-scale kinetic energy and the meridional fluxes of sensible and latent heat, which appeared to be non-negligible, mainly in the storm tracks in winter. Our analysis attests that the most pronounced contribution of TOMs to the aforementioned equations comes from the self-advection by the horizontal synoptic-scale motions, while the TOMs induced by the metric terms in the original equations, and specifically the TOMs associated with the vertical self-advection by the synoptic-scale motions, are much less important.

How to Cite: Petoukhov, V., Eliseev, A.V., Klein, R. and Oesterle, H., 2008. On statistics of the free-troposphere synoptic component: an evaluation of skewnesses and mixed third-order moments contribution to the synoptic-scale dynamics and fluxes of heat and humidity. Tellus A: Dynamic Meteorology and Oceanography, 60(1), pp.11–31. DOI: http://doi.org/10.1111/j.1600-0870.2007.00276.x
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  Published on 01 Jan 2008
 Accepted on 21 Aug 2007            Submitted on 17 Oct 2006

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