Mechanisms underlying temperature extremes in Iberia: a Lagrangian perspective ...

The mechanisms underlying the occurrence of temperature extremes in Iberia are analysed considering a Lagrangian perspective of the atmospheric flow, using 6-hourly ERA-Interim reanalysis data for the years 1979–2012. Daily 2-m minimum temperatures below the 1st percentile and 2-m maximum temperatur...

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Bibliographic Details
Main Authors: Santos, João A., Pfahl, Stephan, Pinto, Joaquim G., Wernli, Heini
Format: Article in Journal/Newspaper
Language:English
Published: ETH Zurich 2015
Subjects:
Temperature extremes
Cold episodes
Warm episodes
Lagrangian trajectories
Large-scale circulation
Surface fluxes
Iberian Peninsula
ERA-Interim
North Atlantic
Online Access:https://dx.doi.org/10.3929/ethz-b-000101056
http://hdl.handle.net/20.500.11850/101056
Description
Summary:The mechanisms underlying the occurrence of temperature extremes in Iberia are analysed considering a Lagrangian perspective of the atmospheric flow, using 6-hourly ERA-Interim reanalysis data for the years 1979–2012. Daily 2-m minimum temperatures below the 1st percentile and 2-m maximum temperatures above the 99th percentile at each grid point over Iberia are selected separately for winter and summer. Four categories of extremes are analysed using 10-d backward trajectories initialized at the extreme temperature grid points close to the surface: winter cold (WCE) and warm extremes (WWE), and summer cold (SCE) and warm extremes (SWE). Air masses leading to temperature extremes are first transported from the North Atlantic towards Europe for all categories. While there is a clear relation to large-scale circulation patterns in winter, the Iberian thermal low is important in summer. Along the trajectories, air mass characteristics are significantly modified through adiabatic warming (air parcel descent), ... : Tellus A: Dynamic Meteorology and Oceanography, 67 (1) ...

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