Plots of raw backscatter profiles from the MST Radar Facility's Vaisala LD40 laser ceilometer, Capel Dewi, Wales obtained during the Icelandic Volcano, Eyjafjallajokull, erupting from 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.

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.

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 Leosphere and Halo Doppler Lidar images from the Chilbolton Observatory, Hampshire.

The Aerosol Direct Radiative Impact Experiment (ADRIEX) was a joint UK Met Office/Natural Environment Research Council (NERC)/UK Royal Society/University of Oslo project aiming at improving our understanding of the radiative effects of anthropogenic aerosol and gases (ozone and methane) in the troposphere. This dataset contains CO ouputs from the TOMCAT model. “Chemical attributes” are found by interpolating chemical distributions (in space and time) from a global chemical transport model to the origin of each trajectory (using its full length). During the ICARTT campaign the TOMCAT global CTM is being run in near-real time (about 19 hours behind present) driven by wind analyses from the ECMWF. The back trajectories are sufficiently long that a TOMCAT chemical analysis exists even at the origin of forecast trajectories. For example, the longest forecast lead time for the Azores domain is 5 days but the back trajectories are 7 days long so that the TOMCAT fields dating from 2 days before the latest meteorological analysis are used to find the attributes. For the US East Coast domain the back trajectories are shorter (3 days long) but the longest lead time is also 3 days so that the chemical attributes can be calculated as soon as TOMCAT has been brought up to date with the latest ECMWF analyses.

The Aerosol Direct Radiative Impact Experiment (ADRIEX) was a joint UK Met Office/Natural Environment Research Council (NERC)/UK Royal Society/University of Oslo project aiming at improving our understanding of the radiative effects of anthropogenic aerosol and gases (ozone and methane) in the troposphere. This dataset contains NOx outputs from the TOMCAT model. “Chemical attributes” are found by interpolating chemical distributions (in space and time) from a global chemical transport model to the origin of each trajectory (using its full length). During the ICARTT campaign the TOMCAT global CTM is being run in near-real time (about 19 hours behind present) driven by wind analyses from the ECMWF. The back trajectories are sufficiently long that a TOMCAT chemical analysis exists even at the origin of forecast trajectories. For example, the longest forecast lead time for the Azores domain is 5 days but the back trajectories are 7 days long so that the TOMCAT fields dating from 2 days before the latest meteorological analysis are used to find the attributes. For the US East Coast domain the back trajectories are shorter (3 days long) but the longest lead time is also 3 days so that the chemical attributes can be calculated as soon as TOMCAT has been brought up to date with the latest ECMWF analyses.

The Aerosol Direct Radiative Impact Experiment (ADRIEX) was a joint UK Met Office/Natural Environment Research Council (NERC)/UK Royal Society/University of Oslo project aiming at improving our understanding of the radiative effects of anthropogenic aerosol and gases (ozone and methane) in the troposphere. This dataset contains O3 outputs from the TOMCAT model. “Chemical attributes” are found by interpolating chemical distributions (in space and time) from a global chemical transport model to the origin of each trajectory (using its full length). During the ICARTT campaign the TOMCAT global CTM is being run in near-real time (about 19 hours behind present) driven by wind analyses from the ECMWF. The back trajectories are sufficiently long that a TOMCAT chemical analysis exists even at the origin of forecast trajectories. For example, the longest forecast lead time for the Azores domain is 5 days but the back trajectories are 7 days long so that the TOMCAT fields dating from 2 days before the latest meteorological analysis are used to find the attributes. For the US East Coast domain the back trajectories are shorter (3 days long) but the longest lead time is also 3 days so that the chemical attributes can be calculated as soon as TOMCAT has been brought up to date with the latest ECMWF analyses.

The Aerosol Direct Radiative Impact Experiment (ADRIEX) was a joint UK Met Office/Natural Environment Research Council (NERC)/UK Royal Society/University of Oslo project aiming at improving our understanding of the radiative effects of anthropogenic aerosol and gases (ozone and methane) in the troposphere. This dataset contains ECMWF Convective precipitation model from a ECMWF Computer.

The Aerosol Direct Radiative Impact Experiment (ADRIEX) was a joint UK Met Office/Natural Environment Research Council (NERC)/UK Royal Society/University of Oslo project aiming at improving our understanding of the radiative effects of anthropogenic aerosol and gases (ozone and methane) in the troposphere. This dataset contains ECMWF High level cloud model from a ECMWF Computer.

The Aerosol Direct Radiative Impact Experiment (ADRIEX) was a joint UK Met Office/Natural Environment Research Council (NERC)/UK Royal Society/University of Oslo project aiming at improving our understanding of the radiative effects of anthropogenic aerosol and gases (ozone and methane) in the troposphere. This dataset contains ECMWF Low level cloud model from a ECMWF Computer.

The Meteosat Second Generation (MSG) satellites, operated by EUMETSAT (The European Organisation for the Exploitation of Meteorological Satellites), provide almost continuous imagery to meteorologists and researchers in Europe and around the world. These include visible, infra-red, water vapour, High Resolution Visible (HRV) images and derived cloud top height, cloud top temperature, fog, snow detection and volcanic ash products. These images are available for a range of geographical areas. This dataset visible images from MSG satellites over the Mediterranean. Imagery available from March 2005 onwards at a frequency of 15 minutes (some are hourly) and are at least 24 hours old. The geographic extent for images within this datasets is available via the linked documentation 'MSG satellite imagery product geographic area details'. Each MSG imagery product area can be referenced from the third and fourth character of the image product name giving in the filename. E.g. for EEAO11 the corresponding geographic details can be found under the entry for area code 'AO' (i.e West Africa).