Radar imaging of Icelandic eruptions: Lessons learnt and future preparations

As a result of the impact of Eyjafjallajökull eruption on aviation in the northern hemisphere in 2010 it was obvious that improved methods and instruments for plume monitoring in Iceland were essential. During the 2010 eruption the Icelandic met office (IMO) was operating one C-band Doppler radar located at Keflavik international airport which is some distance from the eruption site. In cooperation with the international civil aviation organization(ICAO) IMO has recently invested in two moveable X-band dual-polarization Doppler radars and one fixed C-band Doppler radar.

The objectives of these upgrades are to get better radar coverage of Iceland and acquire higher resolution data to improve ash particle resolution and mass ejection estimates. The installation of the fixed C-band radar on the east part of Iceland was completed in April 2012 and, in combination with the existing C-band radar at Keflavik airport IMO has now extended the continuous coverage to almost all of Iceland. The two moveable X-band radars are intended to be rapidly deployable to pre-planned sites near erupting volcanos to provide the best possible data quality. The first moveable radar was delivered in June 2012 and the second one will be delivered at beginning of 2013.

During the design of the moveable radars and trailers several uniquely Icelandic issues had to be considered. To be able to transport the moveable radars to the vicinity of many of Iceland's active volcanos the design of both the radar and the trailer need to be able to withstand the rough terrain on the Icelandic mountain tracks which provide the only access to the highlands. For example conventional trailers and tyres are not suitable for the Icelandic highlands where the winter snowfall and un-cleared roads require special low pressure tyres and high ground clearance. Winter weather conditions and limited daylight also complicate access, as can the ash fall from the eruption itself.

The remoteness of many of the locations and possible eruption-induced complications such as flood-damaged roads mean that the radar teams need to be independent and self-sufficient regarding power, communications and accommodation. Through careful planning and practice it is hoped that the radars can be deployed within a few hours of the start of an eruption and operated continuously, while ideally providing real-time images and data to allow for accurate ash tracking and ash-cloud modelling. This in turn should provide more accurate predictions of ash cloud effects, hopefully minimising the impact of the next eruption on the transport network, and improving our understanding of ash cloud dynamics.