Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates

International audienceA light aircraft was equipped with a bank of Condensation Particle Counters (CPCs) (50% cut from 3?5.4?9.6 nm) and a nano-Scanning Mobility Particle Sizer (nSMPS) and deployed along the west coast of Ireland, in the vicinity of Mace Head. The objective of the exercise was to provide high resolution micro-physical measurements of the coastal nucleation mode in order to map the spatial extent of new particle production regions and to evaluate the evolution, and associated growth rates of the coastal nucleation-mode aerosol plume. Results indicate that coastal new particle production is occurring over most areas along the land-sea interface with peak concentrations at the coastal plume-head in excess of 106 cm?3. Pseudo-Lagrangian studies of the coastal plume evolution illustrated significant growth of new particles to sizes in excess of 8 nm approximately 10 km downwind of the source region. Close to the plume head (?1, decreasing gradually to 53?72 nm h?1 at 3 km. Further along the plume, at distances up to 10 km, the growth rates are calculated to be 17?32 nm h?1. Growth rates of this magnitude suggest that after a couple of hours, coastal nucleation mode particles can reach significant sizes where they can contribution to the regional aerosol loading

Visible Deliverances: The Fact and Figure of Miracle in Eighteenth-Century America

In my dissertation, "Visible Deliverances: The Fact and Figure of Miracle in Eighteenth-Century America," I argue that the idea of the miraculous was a vital resource for the representation of physical and spiritual experience in eighteenth century America. If the peculiar power of a miracle is that it can disrupt apparently fundamental systems like time and causation, that same unique power constituted its great virtue for the Protestant thinkers in my study. The idea of the miraculous suspension of natural law dramatized the subordination of all perceived order to the will of God. Consequently this shock of divine power was a useful construct for the purposes of pious exhortation. In a deeper sense, however, it allowed the clerical writers I focus on to imagine the link between divine power and the contingent structures of human understanding. In "Visible Deliverances" I argue that this work of writing the human relation to the divine through miracle took place in the imaginative space of literary representation. Faced with the incommensurability of human perception and divine force, these writers turned to allusive figural strategies. It was only figural comparison - a practice of spiritualizing analogy - that could place human experience in a defensible relation to the immensity of God's greatest works of power. In an initial chapter on miracles stories in Cotton Mather's medical writing, I argue that he advocated for these stories as necessary evidence for understanding the full scope of physical experience. In my second chapter I read George Whitefield's sermons on Christ's miracles in the context of early-eighteenth-century English religious controversies. In a final chapter, I describe the complexity of Jonathan Edwards' approach to the persistence of miraculous power in the world, an idea that he disavowed, but could not fully relinquish. Ultimately I argue that the principle of contemporary miracle is what allows these writers to describe the full power of the essential evangelical experience of spiritual rebirth

Airborne measurements of nucleation mode particles II: boreal forest nucleation events

International audienceAirborne measurements of nucleation mode aerosol concentrations during nucleation events over the boreal forest of southern Finland are reported. Three case studies are analysis in an attempt to characterise the spatial scales over which these events occur and to identify the source region for particle production. For the cases presented, there is no evidence of nucleation mode particles in the Free Troposphere. Nucleation mode particles are first detected in the surface layer as the nocturnal inversion breaks up and develops into the current-day's new boundary layer. In terms of spatial variability, significant variability in the concentration of nucleation mode particles was observed and was attributed to changes in the topography which comprised a mix of forest canopy and frozen lakes. Measurements over the Gulf of Bothnia indicated no nucleation mode over the sea and confirm that the scale of the events is associated with the boreal forest scale and that the new particles are produced directly above the forest canopy