The role of the West African Monsoon in the tropical to mid-latitudes climate

The interaction between atmosphere–land–ocean–biosphere systems plays a prominent role on the atmospheric dynamics and on the convective rainfall distribution over the West Africa monsoon area during the boreal summer. In particular, the initialization of convective systems in the Sub – Sahelian region has been directly linked to soil moisture heterogeneities identified as the major triggering, development and propagation of convective systems. The present study aims at investigating African monsoon large scale convective dynamics and rainfall diurnal cycle through an exploration of the hypothesis behind the mechanisms of a monsoon phenomenon as an emergence of a collective dynamics of many propagating convective systems. Such hypothesis is based on the existence of an internal self – regulation mechanism among the various components. To achieve these results a multiple analysis was performed based on remote sensed rainfall dataset, and global and regional modelling data for a period of 5 seasons: 2004 - 2008. Satellite rainfall data and convective occurrence variability were studied for assessing typical spatio – temporal signatures and characteristics with an emphasis to the diurnal cycle footprint. A global model and regional model simulation datasets, specifically developed for this analysis and based on Regional Atmospheric Modelling System – RAMS, have been analysed. Results from numerical model datasets highlight the evidence of a synchronization between the destabilization of the convective boundary layer and rainfall occurrence due to the solar radiation forcing through the latent heat release. This supports the conclusion that the studied interacting systems are associated with a process of mutual adjustment of rhythms. Furthermore, this rainfall internal coherence was studied in relation to the West African Heat Low pressure system, which has a prominent role in the large scale summer variability over the Mediterranean area since it is acting as one of dynamic link between sub tropical and midlatitudes variability.

Mapping socialist solidarities: SWAPO, the Namibian liberation struggle, and the Global Cold War

This thesis addresses the entanglements between the Namibian liberation struggle and the global Cold War, focusing on the socialist support provided to the South West African People Organization (SWAPO), the liberation movement that fought for the independence of the country from the South African regime. This thesis aims at analyzing three socialist models of solidarity with the SWAPO’s struggle that developed especially from the late 1970s. Combining archival sources and biographical accounts, it examines the politics of solidarity with SWAPO implemented by East Germany, Cuba, and the Italian Communist Party. The interest lies in understanding how solidarity was declined and received by internal promoters and external addressees. Thus, I explore how these three actors constructed their concept of solidarity with SWAPO according to their national and ideological contexts and how this was received by the SWAPO members who experienced it in various ways. Each socialist actor promoted solidarity with SWAPO by using varying narratives, pursuing their own objectives, and employing diverse instruments, thus carrying out different and sometimes competing visions of socialism and solidarity. On its side, SWAPO was able to take advantage from such visions, as each of them could serve its different needs in diverse ways. In providing a general overview of these three solidarity policies, this thesis has the objective of highlighting the internal pluralization of the “socialist solidarity regime” while at the same time contributing to the debate on the extent of SWAPO’s commitment to socialism during the Namibian liberation struggle. It argues that, while pragmatism has always guided SWAPO during the liberation struggle and the post-independence period, and non-alignment has always been its international stance, socialism has to some extent been a model for the revolution in Namibia, to the point that it is still influencing the SWAPO party today.