Emerging Storms: Glacier Dust and Climate Change

Posted by on Aug 27, 2015

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When the sand plains of southern Iceland dry out, they form active dust sources under the right weather conditions.

When the sand plains of southern Iceland dry out, they form active dust sources under the right weather conditions.

Dust storms are most often associated with hot deserts. However, there are 5 million square kilometres of cold arid land globally where significant dust storms have been reported. The combination of sparse vegetation and strong winds make some humid cold climate areas important dust sources. These can be found in Alaska, Canada, Greenland and Iceland in the northern hemisphere, and Patagonia, Antarctica and New Zealand in the southern hemisphere.

The relationship between glaciers and dust is complex. Glacier retreat produces dust, which if mobilised can fall on glaciers, increasing heat absorption, promoting further retreat. Or, it can create an armour on the exposed area in front of the glacier, reducing dust emissions. Current research is looking to develop a more nuanced understanding of the opposed effects of this glacier dust. It may be that one of them is the predominant one in most areas, or that they are in relatively balance, or that each one is the major force, but only in specific regions.

In Southern Iceland, dust sourced from extensive sand plains can travel over 200 km to the capital city, Reykjavik. This leads to air pollution, causes travel disruptions and can impact human health. Glacially derived dust that is transported to the ocean can provide soluble iron, such as in the Gulf of Alaska, which potentially boosts productivity of marine ecosystems. If the Antarctic ice-sheet shrinks to become land terminating, the potential dust load available would be c.300 Mt/yt – equivalent to the total contemporary dust emissions from Asia. However, the conditions which produce dust storms in cold climate and high latitude environments, and the subsequent impacts, have not been fully assessed.

Dust storms reduce visibility in Southern Iceland. These DustTrak instruments determine the amount of dust in suspension and the particle sizes.

Dust storms reduce visibility in Southern Iceland. These DustTrak instruments determine the amount of dust in suspension and the particle sizes.

Monitoring dust storms is a challenge. They are not always active, and can cover several hundred kilometres. Satellite remote sensing has revealed the distances that these dust storms can travel, but capturing events in this way is hindered by cloud cover. It is also difficult to measure how much dust is being transported and deposited. Taking direct measurements in the field allows for direct measurements to be made, including total dust concentrations and the particle sizes.

These stations are spatially sparse, and normally only in operation for a few months of the year. More permanent stations require human intervention to collect samples from the traps, which could be days or weeks apart.

Constant monitoring can be achieved for a period of time during a field campaign, where researchers hope for good amounts of dust movement. In addition, increased snow and ice cover, together with darkness during the winter months means that research focus is placed predominantly during the summer months, despite dust storms taking place throughout the year.

To address the scarcity of existing data, the High Latitude and Cold Climate Dust Network (HLCCD)  has formed. Administered from Loughborough University in the UK, it brings together collaborators from the UK, Iceland, USA, Canada and Argentina to tackle problems associated with dust storms. It aims to collate existing data, and to highlight areas where further work is required.

Wind tower set up during fieldwork in Southern Iceland, June 2015, along with dust traps, to monitor dust transport under varying wind conditions.

Wind tower set up during fieldwork in Southern Iceland, June 2015, along with dust traps, to monitor dust transport under varying wind conditions.

The network has started by producing a bibliographic map, highlighting all the existing dust research in cold environments and the high latitudes. The next step is to map potential dust sources, determined by geomorphological and climatic variables. This will enable researchers to better understand what is required to produce an active dust source and how dust sources could change in the future. Changes could be caused by retreating glaciers, or a change in land use. This will allow an assessment on how air quality and marine ecosystems will be affected in the future.

The network is still in its infancy, but it hopes to provide a basis to facilitate interdisciplinary research. By bringing together researchers with different specialities (remote sensing, aeolian processes, oceanography and climate science), the network is able to tackle the complex questions, which remain regarding dust production, transport and deposition in high latitudes and cold environments.

Find out more about the HLCCD Network: www.hlccd.org and @HLCCD

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