Detection of coherent airstreams using cluster analysis: application to an extratropical cyclone

Flow in geophysical fluids is commonly summarized by coherent streams, for example conveyor belt flows in extratropical cyclones or jet streaks in the upper troposphere. Typically, parcel trajectories are calculated from the flow field and subjective thresholds are used to distinguish coherent streams of interest. This methodology contribution develops a more objective approach to distinguish coherent airstreams within extratropical cyclones. Agglomerative clustering is applied to trajectories along with a method to identify the optimal number of cluster classes. The methodology is applied to trajectories associated with the low-level jets of a well-studied extratropical cyclone. For computational efficiency, a constraint that trajectories must pass through these jet regions is applied prior to clustering; the partitioning into different airstreams is then performed by the agglomerative clustering. It is demonstrated that the methodology can identify the salient flow structures of cyclones: the warm and cold conveyor belts. A test focusing on the airstreams terminating at the tip of the bent-back front further demonstrates the success of the method in that it can distinguish fine-scale flow structure such as descending sting jet airstreams.

Voting rights of refugees

The book develops a novel legal argument about the voting rights of recognised 1951 Geneva Convention Refugees. The main normative contention is that such refugees should have the right to vote in the political community where they reside, assuming that the political community is a democracy and that its citizens have the right to vote. The basis of this contention is that the right to political participation in some political community is a basic right from the point of view of dignity and the protection of one’s interests. Due to their unique political predicament, 1951 Geneva Convention Refugees are a special category of non-citizen residents. They are unable to participate in elections of their state of origin, do not enjoy its diplomatic protection and consular assistance abroad, and – most fundamentally – are unable or unwilling, owing to a well-founded fear of persecution, to return to it; thus, they are in limbo for a potentially protracted period. Refugees, too, deserve to have a place in the world in the Arendtian sense, where their opinions are significant and their actions are effective. Their state of asylum is, for the time being, the only community in which there is any realistic prospect of political participation on their part.