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Relationship between convection over Central America and the intensity of the jet stream bearing on the 1999 December European storms
Author(s) -
Ricard Didier,
Arbogast Philippe,
Crépin Fabien,
Joly Alain
Publication year - 2011
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.931
Subject(s) - extratropical cyclone , climatology , jet stream , rossby wave , teleconnection , convection , trough (economics) , mesoscale convective system , geology , precipitation , storm , tropical cyclone , atmospheric sciences , meteorology , jet (fluid) , mesoscale meteorology , geography , oceanography , physics , el niño southern oscillation , macroeconomics , economics , thermodynamics
During 26–28 December 1999, two very powerful and devastating extratropical cyclones hit Western Europe. These two storms were associated with an upper‐level zonal jet, remarkable in its intensity and its large extension over the Atlantic Ocean. In this study, we focus on the relationship between the exceptional features of this jet stream and some heavy precipitation that occurred over Central America during mid‐December. A Rossby‐wave train excited by strong convective activity over this area is likely to play a key role in this teleconnection. To assess this tropical–extratropical interaction, several numerical experiments have been performed with the French global model ARPEGE. Firstly, the effects of convection have been neutralized within a domain localized over Central America. Then, to combine the model with observations, a new strategy has been devised. Within a selected window, the parametrized latent heat release has been deduced from Tropical Rainfall Measuring Mission (TRMM) precipitation data, translated in terms of a potential vorticity (hereafter PV) source and incorporated into the model using PV inversion. These simulations show, in particular, that the convective activity over Central America triggers a wave train that moves poleward and eastward with the group velocity, finally to strengthen the North Atlantic jet stream, leading to windstorms Lothar and Martin . Copyright © 2011 Royal Meteorological Society