The Icelandic Dust Cycle: insights from remote sensing and air parcel trajectory modelling
1, Joanna Bullard1, Tom Mockford1, Santiago Gasso2, Throstur Thorsteinsson3
1Loughborough University, Loughborough, Leicestershire, UK, 2GESTAR/NASA, Silver Spring, Maryland, USA, 3University of Iceland, Reykjavik, Iceland
A detailed picture of global dust emissions at low latitudes has been achieved through the use of remote sensing. However, most surveys have been restricted to latitudes between 50°N and S and have not considered dust from high latitude regions. Field studies have shown that dust emissions, particularly from glacierised areas, at high latitudes can be extremely intense and extensive, but the potential for exploring this activity and the long range transport at larger spatial and longer temporal scales using remote sensing remains unrealised.
This research applies techniques for remote sensing of dust that have been successful at low latitudes to high latitude regions by adopting a scale of enquiry appropriate to identify patterns and trends in Icelandic dust emissions from 2003-2014. It uses broad-scale aerosol products (Aerosol Optical Depth retrievals from MODIS at 10x10 km and 1 degree) for obtaining information on the dynamics of dust source regions and combines these with HYSPLIT air parcel trajectory modelling to establish dust transport pathways.
Examination of AOD over land indicates that the frequency and intensity of dust emissions varies spatially, with the glacial outwash plains of Skeidarasandur identified as a particularly persistent dust source, which is in accordance with other research. In terms of temporal variability, the research reveals that dust storms occur throughout the year, however a distinct seasonality can be discerned with highest dust emissions during the spring and a second, lower peak during autumn. HYSPLIT climatologies for dusty days indicate the potential for dust delivery into the northern Atlantic from southern Iceland sources, and more of an Arctic Ocean destination for northern Icelandic sources.