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Eyjafjallajokull Volcanic Ash Cloud: NCAS FGAM Instruments

Update Frequency: Not Planned
Latest Data Update: 2010-05-11
Status: Completed
Online Status: ONLINE
Publication State: Published
Publication Date: 2014-09-19
Download Stats: last 12 months
Dataset Size: 88 Files | 12MB


The Icelandic Volcano, Eyjafjallajokull, started erupting on 14th April 2010. The volcanic ash cloud produced covered much of Northern Europe for several weeks causing extensive disruption to air travel. The UK and European atmospheric communities had many instruments - both airborne and ground-based, remote sensing and in-situ - taking measurements of the ash cloud throughout this period. This dataset contains images from Aberystwyth elight and water-vapour lidars, FGAM lidar situated at Cardington and Salford Urban Built-Environment Research Base lidar.

Ash was seen frequently over Capel Dewi and Cardington during the periods 13th - 23rd April 2010 and 11th - 17th May. The ash tended to occur in single, narrow, uniform layers during the first period but in multiple, thicker, patchy layers during the second period. Work has begun on trying to determine the properties of the ash from the lidar observations. A comparison of the Raman lidar returns at 355 and 387 nm gives the lidar (optical extinction to backscatter) ratio. The unexpectedly (and controversially) large mean values for the April period (182) suggest that the ash particles were much larger and darker than those associated with eruptions of Mount Etna (mean lidar ratio values of 55). DK confirmed that similarly large values were found for observations made by an airborne lidar system.

The ultimate aim of this type of work is to be able to define the ash source function, which is required to initiate the dispersion model. For example, how much mass was ejected and to what heights? Moreover, how did the ash particles behave one they are airborne? For example, how quickly, did they start to sediment? DK clarified that high pressure over the British Isles appeared to be the driving force which caused the ash to enter the BL - not sedimentation. In order to improve the interpretation of remote sensing data, more will need to be known about the properties of the ash particles, e.g. their complex refractive index. It may be necessary to improve the lidar scattering models for this type of particle, e.g. to encompass Mie scattering.

Citable as:  National Centre for Atmospheric Science (2014): Eyjafjallajokull Volcanic Ash Cloud: NCAS FGAM Instruments. NCAS British Atmospheric Data Centre, date of citation.
Abbreviation: Not defined
Keywords: Eyjafjallajokull, FGAM Instruments


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Use of these data is covered by the following licence: When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record.
Data lineage:

A copy of these data were made available to the British Atmospheric Data Centre (BADC) to assist the academic community during this volcanic ash event.

Data Quality:
This is quick look unvetted data.
File Format:
Images are PNG formatted

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Process overview

This dataset was generated by instruments deployed on platforms as listed below.
Output Description


  • long_name: Air Temperature
  • gcmd_url:
  • gcmd_keyword: Air Temperature
  • names: Air Temperature,
  • long_name: Atmospheric Pressure Measurements
  • gcmd_url:
  • gcmd_keyword: Atmospheric Pressure Measurements
  • names: Atmospheric Pressure Measurements,
  • long_name: Humidity
  • gcmd_url:
  • gcmd_keyword: EARTH SCIENCE > Atmosphere > Atmospheric Water Vapor > Humidity
  • names:, EARTH SCIENCE > Atmosphere > Atmospheric Water Vapor > Humidity

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