English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/115977
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:


Lagrangian study of an atmospheric blocking event

AuthorsRecuerda-Gavilán, Irene
AdvisorHernández-García, Emilio ; López, Cristóbal
Issue Date2014
PublisherUniversidad de las Islas Baleares
CSIC-UIB - Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC)
AbstractEastern Europe and Western Russia experienced a strong heat wave during the summer months of 2010. Extreme temperatures resulted in over 54,000 of heat-related deaths and many wildfires, in icting large economic losses on Russia (Beilharz et al., 2013). The heat wave was due to a strong atmospheric blocking that persisted over the Euro-Russian region from late June to early August (Matsueda, 2011). Understanding the physical internal processes that produce this blocking will be important for improving regional projections, and may also provide an improved capability for predicting some extreme events. In the case of the 2010 Russian heat wave, it was not readily anticipated from knowledge of either prior climate trends or specific climate forcings, and for which advance warning may thus be limited (Dole et al., 2011). The present work is a study of the atmospheric transport of air particles during the described blocking event, using concepts and methodologies developed in the frame of dynamical systems theory. In particular, the key tool used in this work is the concept of finite-size Lyapunov exponents (FSLE). They measure the relative dispersion of transported particles and, what is more important, can be used to detect Lagrangian coherent structures (LCSs) in the ow. These dynamical structures can be visualized in the atmospheric ow like vortices, barriers to transport or fronts. The use of this kind of techniques has contributed to a better understanding of mixing and transport in the ocean (Hernández-Carrasco, 2013; d'Ovidio et al., 2004) and in the stratosphere (Joseph and Legras, 2002; de la Cámara, 2013). However, Lagrangian tools have never been applied to the case of a tropospheric blocking event. Would they also help to understand tropospheric phenomena, where much more diffusive, turbulent and vertical movements are present and spatio-temporal scales also differ?.
Chapter 2. contains an introduction and a theoretical background about the dfferent topics concerning this work. Firstly, we give an overview of the different processes responsible of the transport in the atmosphere such as advection and diffusion. After that, we introduce how the transport in a time-independent ow can be characterize by hyperbolic points and the associated unstable and stable manifolds, that control the motion of the uid. In the case of time-independent ows like the atmosphere, these manifolds can be "generalized" in LCSs. They act as transport barriers in the uid motion and order the ow into different regions corresponding to different dynamical behavior of the trajectories. Finally, we talk about the blocking event, the atmospheric conditions derived from it and the social consequences that it had. The data and tools used in this work are described in Chapter 3. Here we introduced the Lagrangian particle dispersion model FLEXPART, that allowed to reproduced the required particle trajectories. We also described the procedure to calculate the finite-size Lyapunov exponents fields, the essential variable to extract LCSs. The results of this work are presented in Chapter 4 and the derived conclusions in Chapter 5. The first part of Chapter 4 is dedicated to the study of a temporal sequence of the FSLE fields for the last days of July, when the maximum temperatures were reached in East-Europe. Later, we compare these results with particle trajectories and some typical Eulerian fields like geopotential height and temperature. Final Chapter 5 summarizes the work, exposes conclusions from the results and proposes some ideas that can be developed in the future.
DescriptionMaster’s degree in Physics of Complex Systems at the Iniversitat de les Illes Balears, academin year 2013-2014.
Appears in Collections:(IFISC) Tesis
Files in This Item:
File Description SizeFormat 
lagrangian_study_Recuerda.pdf23,14 MBAdobe PDFThumbnail
Show full item record
Review this work

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.