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© 2014. American Geophysical Union. All Rights Reserved. The authors want to thank three anonymous reviewers. This research was supported by the Ministry of Economy and Competitiveness of Spain under project TRODIM (CGL2007-65891-C02) and MATRES (CGL2012-34221). M.G.E. was funded by FPI grant (BES-2008-005310) and Consolider project (CSD The authors want to thank three anonymous reviewers. 2007-00050), Major Stratospheric Sudden Warmings (SSWs) are characterized by a reversal of the zonal mean zonal wind and an anomalous warming in the polar stratosphere that proceeds downward to the lower stratosphere. In the tropical stratosphere, a downward propagating cooling is observed. However, the strong modulation of tropical winds and temperatures by the quasi-biennial oscillation (QBO) renders accurate characterization of the tropical response to SSWs challenging. A novel metric based on temperature variations relative to the central date of the SSW using ERA-Interim data is presented. It filters most of the temperature structure related to the phase of the QBO and provides proper characterization of the SSW cooling amplitude and downward propagation tropical signal. Using this new metric, a large SSW-related cooling is detected in the tropical upper stratosphere that occurs almost simultaneously with the polar cap warming. The tropical cooling weakens as it propagates downward, reaching the lower stratosphere in a few days. Substantial differences are found in the response to SSWs depending on the QBO phase. Similar to what is observed in the polar stratosphere, tropical SSW-associated temperatures persist longer during the west QBO phase at levels above about 40 hPa, suggesting that the signal is mainly controlled by changes in the residual mean meridional circulation associated with SSWs. Conversely, in the lower stratosphere, around 50–70 hPa, enhanced cooling occurs only during QBO east phase. This behavior seems to be driven by anomalous subtropical wave breaking related to changes in the zero-wind line position with the QBO phase., Ministry of Economy and Competitiveness of Spain, FPI grant, Consolider project, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Major Stratospheric Sudden Warmings (SSWs) are characterized by a reversal of the zonal mean zonal wind and an anomalous warming in the polar stratosphere that proceeds downward to the lower stratosphere. In the tropical stratosphere, a downward propagating cooling is observed. However, the strong modulation of tropical winds and temperatures by the quasi-biennial oscillation (QBO) renders accurate characterization of the tropical response to SSWs challenging. A novel metric based on temperature variations relative to the central date of the SSW using ERA-Interim data is presented. It filters most of the temperature structure related to the phase of the QBO and provides proper characterization of the SSW cooling amplitude and downward propagation tropical signal. Using this new metric, a large SSW-related cooling is detected in the tropical upper stratosphere that occurs almost simultaneously with the polar cap warming. The tropical cooling weakens as it propagates downward, reaching the lower stratosphere in a few days. Substantial differences are found in the response to SSWs depending on the QBO phase. Similar to what is observed in the polar stratosphere, tropical SSW-associated temperatures persist longer during the west QBO phase at levels above about 40 hPa, suggesting that the signal is mainly controlled by changes in the residual mean meridional circulation associated with SSWs. Conversely, in the lower stratosphere, around 50-70 hPa, enhanced cooling occurs only during QBO east phase. This behavior seems to be driven by anomalous subtropical wave breaking related to changes in the zero-wind line position with the QBO phase. Key Points New methodology to analyze SSW on the tropical stratosphere There are differences in the SSW tropical cooling according to QBO phase Zero-wind line position plays an important role in SSW tropical response ©2014. American Geophysical Union. All Rights Reserved.

We thank the Stratospheric Research Group of the FUB for preparing the stratospheric data. This research was supported by the Ministry of Economy and Competitivity of Spain under project TRODIM (CGL2007-65891-C02 and CGL2008-05968-C02-01). MGE was funded by FPI grant (BES-2008-005310). We are grateful to two referees for their helpful comments., Stratospheric Sudden Warmings (SSWs) strongly affect the polar stratosphere during winter months mainly in the Northern Hemisphere. The intraseasonal distribution and type of SSWs for the 1958-1979 and 1979-2002 periods in ERA-40 and NCEP-NCAR reanalyses reveal differences. In the pre-satellite era, most events occur in January and are vortex splits. In the post-satellite era, the distribution is bimodal (peaking in December and February), and shows more displacement events. The difference in the seasonal distribution of SSWs leads to changes in the climatological state of stratospheric temperatures, with differences up to 5.9 K at 10 hPa and 3.6 K at 20 hPa in February between pre- and post-1979 periods. We find that the temperature evolution at 20 hPa is in better qualitative agreement with theoretical expectations than at 10 hPa. Hence, 10 hPa may be affected more strongly by artifacts related with satellite data assimilation, which have, however, limited impact on identification of SSWs., Ministry of Economy and Competitivity of Spain, Project TRODIM, FPI grant, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

The term 'nationalization', which refers to the mechanisms that integrate, both vertically and horizontally, a state's political system, has recently achieved a preeminent place in the field of subnational politics, particularly when the focus is on the party system, electoral coordination between districts, political careers, and legislative and government coalitional dynamics. This article argues that although there is a certain degree of consensus about its broader meaning, there is no such consensus when the term 'nationalization' is applied to federal, regionally decentralized or multinational states. In these cases it is necessary to place the focus on two theoretical issues that have generally not been taken into account. On the one hand, (a) the analogous institutional origin of national and subnational civic communities on which the idea of 'rational consensus' in the formation of representative democracy rests and, on the other, (b) the instrumental character of national parties as a means of endogenously justifying the coordination of the strategic inter-district entry of political elites. By clarifying these two points, it is possible to theoretically link the presence of multiple political identities, territorially institutionalized interests, with models of political coordination that are in partial equilibrium or completely nationalized., El término "nacionalización", con el cual se alude a los mecanismos que integran vertical y horizontalmente los sistemas políticos estatales, ha cobrado recientemente un lugar preeminente en el campo de los estudios sobre política subnacional; particularmente cuando el interés está centrado en el sistema de partidos, la coordinación electoral entre distritos, las carreras políticas y la dinámica coalicional legislativa y gubernamental. En estas notas se plantea que si bien existe cierto consenso sobre su significado más amplio, no sucede lo mismo cuando se lo aplica a estados federales, regionales descentralizados o multinacionales, ya que en estos casos resulta necesario enfocar la mirada con mayor detenimiento hacia dos cuestiones teóricas que en general no han sido tenidas en cuenta. Por un lado (a) el análogo origen institucional de las comunidades cívicas nacionales y subnacionales sobre las cuales se sustenta la idea de "consenso racional" en la formación de la democracia representativa, y por el otro (b) el carácter instrumental de los partidos nacionales como medio para justificar endógenamente la coordinación de la entrada estratégica interdistrital de las elites políticas. El esclarecimiento de ambas cuestiones, se sostiene, permitiría vincular teóricamente la presencia de identidades políticas múltiples, intereses territorialmente institucionalizados con modelos de coordinación política en equilibrio parcial o totalmente desnacionalizados.