From: Joe Winters, EurekAlert
Published June 3, 2010 09:33 AM
Electric ash found in Eyjafjallajokull's plume, say
UK researchers
The paper, to be published today, Thursday 27 May, in IOP
Publishing's Environmental Research Letters, is published as the UK
continues to face the possibility of further flight disruption from
future volcanic activity.
Shortly after the volcano's active eruption phase began in mid-April,
the Met Office contacted Joseph Ulanowski from the Science and
Technology Research Institute at the University of Hertfordshire, who
last year, together with Giles Harrison from the Department of
Meteorology at the University of Reading, had developed a specialist
weather balloon which could assess the location and composition of the
volcanic ash clouds.
Their balloons, originally designed and used to study the properties of
desert dust clouds, are able to assess not only the size of atmospheric
particles but also the electric charge present.
Measurements made last year with the balloons in Kuwait and off the west
coast of Africa showed clearly that desert dust could become strongly
electrified aloft. Charging modifies particle behaviour, such as how
effectively particles grow and are removed by rain.
A hastily scrambled team travelled to a site near Stranraer in Scotland
where a balloon was launched, detecting a layer of volcanic ash 4km
aloft, about 600m thick, with very abrupt upper and lower edges.
From their measurements, the researchers conclude that neither energy
from the volcanic source - more than 1200 kilometres away - nor weather
conditions could have been responsible for the position of the charge
found by the balloon.
The presence of charge deep inside the plume, rather than on its
upper and lower edges, contradicts expectations from models assuming
solely weather-induced charging of layer clouds.
Giles Harrison said, "Detailed volcanic plume properties, such as the
particle size, concentration and charge found by our weather balloon are
important in predicting the impact on aircraft."
###
The paper can be found in IOP Publishing's open-access journal
Environmental Research Letters at
http://iopscience.iop.org/1748-9326/5/2/024004/fulltext from
Thursday 27 May.
Contact: Joe Winters
joseph.winters@iop.org
44-207-470-4815
Institute of Physics
http://www.eurekalert.org
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