92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Wednesday, 25 January 2012
Correlation Between the Latitudinal Position of the Extratropical Jet Stream in the Atlantic Basin and Moderate Weather Extremes in Europe
Hall E (New Orleans Convention Center )
Irina Mahlstein, NOAA; and O. Martius, D. Ginsbourger, and C. Chevalier

The latitudinal position of the extratropical jet stream over the north Atlantic basin determines the pathway of weather systems across the Atlantic and Europe. The passage of weather systems across the continent determines the occurrence of extreme weather in Europe. Close links are, for example, expected to exist between the location of the jet stream, the tracks of individual storms, and high-wind and potentially precipitation events. A direct connection between moderately extreme temperature events and the upstream position of the jet is less intuitive. Here we explore correlations between the latitudinal position of the jet over the Atlantic basin and moderate extremes in temperature, wind and precipitation for a 44-year time period. We use a 44-year time series of the latitudinal position of the extatropical jet over the Atlantic extracted from the ERA-40 re-analysis data set (Woollings et al. 2010). Following Woollings et al. (2010) the time series was split into three groups according to the latitudinal jet position (southern, central, northern jet). The jet time series was then correlated with time series of moderate extremes in the surface temperature and wind records from the ERA-40 data set, the surface temperature records from the ECA&D data set, and with moderate extremes in the E-OBS (Haylock et al. 2008) gridded precipitation data. The correlation was calculated using a logistic regression model. Correlations between the jet state and the occurrence of moderate extreme events are calculated for time lags between 0 and 8 days. Statistically significant correlations exist between the location of the jet and occurrence of moderate high and low temperature extremes and wind extremes at all lags and for the European area, north Africa and Greenland.

Haylock, M.R., N. Hofstra, A.M.G. Klein Tank, E.J. Klok, P.D. Jones, M. New. 2008: A European daily high-resolution gridded dataset of surface temperature and precipitation. J. Geophys. Res., 113, D20119, doi:10.1029/2008JD10201

Woollings T., Hannachi A., Hoskins B., 2010: Variability of the North Atlantic eddy-driven jet stream , Quart. J. Royal. Meteor. Soc., 136, 856-868

We acknowledge the data providers in the ECA&D project (http://eca.knmi.nl). on 7-31-2011-->

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