The balloon is being used to assess the danger to aircraft of the volcanic ash
A weather balloon has been launched in south west Scotland to help analyse the volcanic ash cloud over the UK.
Met Office scientists have been working with the Universities of Reading and Hertfordshire to gather data about the potential danger to aircraft.
The Stranraer balloon launch measured a 500m (1,640ft) thick layer of volcanic dust at a height of about 4,000m (13,123ft).
The technique was originally developed to study dust clouds in the Sahara.
The researchers plan to send the balloon back into the skies over Stranraer on Wednesday morning.
Met Office forecasters helped to identify the best site for the research being led by Prof Giles Harrison of the University of Reading.
He said: "To get good measurements of the ash we needed to be both under the ash plume, but in cloud-free air.
"Fortunately the Met Office predictions for an ideal observation window at a site near Stranraer were bang on, allowing us to launch our balloon to pass directly through the volcanic plume.
"Despite the beguilingly blue sky at Stranraer, the weather balloon measurements showed a layer of volcanic dust at 4km aloft - the plume was about 500m thick, with very abrupt edges."