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Measurable SO2 emissions from Eyjafjallajökull appear to have ceased, at least for the time being.
Ash emissions appear reduced but SO2 emissions continue.
OMI measurements on May 19 show transport of SO2 and ash to high latitudes in the region of Svalbard.
Remnants of previous SO2 and ash emissions are visible over Greenland and north of the UK, whilst fresh emissions are apparent near Eyjafjallajökull. Localization of the emissions near the volcano (and relatively high SO2 column amounts) may be due to light winds.
Screen capture from the Mila webcam at Hvollsvöllur (west of Eyjafjallajökull) on the morning of May 13, showing a sustained eruption column.
A change in wind direction takes the SO2 and ash plume around Iceland to the north-east, and directly over the Faroe Islands.
SO2 and ash continue to disperse over the North Atlantic, Europe and North Africa, whilst fresh emissions from Eyjafjallajökull are apparent.
OMI measurements on May 11 show SO2 as far south as Madeira. SO2 emissions from Eyjafjallajökull appear reduced.
AIRS SO2 retrievals at ~03:45 UT (left) and ~13:25 UT (right); the latter near-coincident with the OMI measurements above.
A nighttime CALIPSO overpass through the North Atlantic region (above) shows multiple aerosol layers at altitudes above ~3 km, perhaps up to ~10 km, between 35ºN and 65ºN. Comparison with the OMI SO2 and AI data suggests that these layers could be a mixture of absorbing aerosol (volcanic ash) and sulfate aerosol.
Nighttime AIRS SO2 retrieval at ~03:00 UT (early in the morning of May 9). AIRS detects a SO2 cloud which had moved further west by the time of the afternoon OMI overpass.
On May 7, OMI detected a diffuse SO2 cloud over Spain, Portugal and France, with the younger SO2 plume curving westwards. SO2 amounts and Aerosol Index values in the plume appear lower than on May 6.
The impressive SO2 plume from Eyjafjallajökull has now shifted west of the European coast. A new pulse of ash is detected by the OMI UV Aerosol Index (AI). High AI values indicate high ash loadings or ash at high altitudes, or a combination of both.
AIRS SO2 retrievals at ~04:10 UT and ~13:50 UT (the latter is a few minutes before the OMI retrievals shown above).
Screen capture from the Mila webcam at Hvollsvöllur (west of Eyjafjallajökull) on the morning of May 6, showing the ash plume rising above the clouds.
Views of the ash plume from Eyjafjallajökull from Terra/MODIS (left) and Aqua/MODIS (right) on April 15. Credit: MODIS Rapid Response System
Ozone Monitoring Instrument (OMI) images of the SO2 and ash cloud on April 15 at ~12:00 UTC. The total SO2 mass measured by OMI in the volcanic cloud was ~3000-4000 tons.
Atmospheric Infrared Sounder (Aqua/AIRS) SO2 retrieval at 13:30 UTC on April 15. For further information on AIRS retrievals see: http://airs.jpl.nasa.gov/story_archive/Iceland-volcano-Eyjafjallajokull/.
MetOp-A Infrared Atmospheric Sounding Interferometer (IASI) retrievals of SO2, ash and ice in the volcanic cloud for April 14-16 (courtesy of Lieven Clarisse/ULB)
Composite of Aqua/MODIS visible image and OMI SO2 data (colored pixels) at ~1330 UTC on April 15
Terra MODIS image of the Eyjafjallajökull ash plume at 12:20 UTC. Credit: MODIS Rapid Response System
Ozone Monitoring Instrument (OMI) images of the SO2 and ash cloud on April 16 at ~08:00-13:00 UTC.
Aqua MODIS image of the Eyjafjallajökull ash plume at 13:20 UTC. Credit: MODIS Rapid Response System
Composite of Aqua/MODIS visible imagery and OMI Aerosol Index on the afternoon of April 17. The ash cloud from activity on April 14-15 is becoming hard to track in the UV data. Fragments of the ash cloud can still be seen over Ukraine and Switzerland. A new pulse of ash from activity on April 16-17 is visible south of Iceland, behind a weather front north of the UK. No SO2 emissions have been detected by OMI in this new pulse. This could indicate: 1) complete scrubbing of SO2 from the eruption cloud; 2) emission of sulfur in the form of hydrogen sulfide (H2S), which is not detectable from space; 3) problems with satellite SO2 retrievals in the dense ash plume; 4) Absence of sulfur species in the eruptive gases (unlikely).
Terra ASTER Thermal Infrared (TIR) image of Eyjafjallajökull and Katla on April 17 at 22:43 UTC (credit: Mike Ramsey, Univ. Pittsburgh). Hot lava flows emitted during the first phase of the eruption at Fimmvörðuháls are clearly visible, as is the new vent on Eyjafjallajökull. A minimum brightness temperature of -36ºC in the eruption plume corresponds to an altitude of ~7 km, based on a radiosonde sounding from Keflavik airport (above right), although the bulk of the ash is at lower altitude.
Eyjafjallajökull for April 14-20. Courtesy of the Atmosphere and Climate Department, NILU, Norway.FLEXPART dispersion model simulation of the emissions from
Terra MODIS image of the Eyjafjallajökull ash plume at 12:05 UTC. The ash plume is partly masked by overlying meteorological clouds, rendering detection difficult. Credit: MODIS Rapid Response System
Composite of MODIS visible images and OMI Aerosol Index data on April 18. Ash emitted from Eyjafjallajökull on April 17 is drifting NW of the UK.
Terra MODIS image of the Eyjafjallajökull ash plume at 12:50 UTC. Credit: MODIS Rapid Response System
OMI Aerosol Index (AI) and SO2 images for April 19. A fresh ash plume from Eyjafjallajökull is visible in the AI data, whilst a more diffuse area of ash seems to be present over the North Sea between the UK and Denmark. In contrast to the April 17 data, SO2 is detected in the April 19 emissions.
This appears to be consistent with independent reports that the eruption is becoming more magmatic rather than phreatomagmatic in character, i.e., there is now less scrubbing of SO2 from the plume.
Terra MODIS image of the Eyjafjallajökull ash plume at 11:55 UTC. The plume is notably more diffuse than in recent days. Credit: MODIS Rapid Response System
Terra MODIS image of Iceland at 12:35 UTC. Ash emissions are visibly reduced. Credit: MODIS Rapid Response System
OMI measurements on April 21 show SO2 emissions from Eyjafjallajökull extending from Iceland to the north of Scotland. This reflects the changing nature of the eruption from a phreatomagmatic event to a predominantly magmatic degassing event.
SO2 amounts are still relatively low, which may indicate a low eruption rate.
Aqua MODIS image of Iceland at 13:35 UTC. The volcanic plume is visible above the cloud deck. Credit: MODIS Rapid Response System
OMI measurements on April 23 show SO2 emissions north of Eyjafjallajökull, indicating a change in wind direction transporting the plume over Reykjavik. The observed SO2 column amounts indicate SO2 emission rates on the order of ~2000-5000 tons/day, depending on wind speed over the volcano.
Aqua MODIS image of Iceland at 12:40 UTC (shortly before the OMI overpass shown above). Credit: MODIS Rapid Response System
OMI measurements on April 24 show SO2 plumes east and west of Eyjafjallajökull, indicating changing wind directions and/or plume altitude. The observed SO2 column amounts near the volcano are the highest measured since the beginning of the eruption. This could indicate low wind speeds at certain altitudes, allowing SO2 to accumulate near the vent, increased SO2 emissions, or improving measurement conditions.
OMI measurements on April 26 show an SO2 plume extending from Eyjafjallajökull across the North Atlantic to northern Norway.
Aqua MODIS image of Iceland at 13:15 UTC. The Eyjafjallajökull gas plume is visible above the cloud deck. Credit: MODIS Rapid Response System
OMI measurements on April 27 show an SO2 plume extending from Eyjafjallajökull across the North Atlantic to southern Norway. A radiosonde sounding from Keflavik airport shows strong wind shear at ~5 km altitude, suggesting that the SO2 plume is rising to this level or higher.
OMI measurements on April 28 show an SO2 plume west of Eyjafjallajökull, and another blob of SO2 further downwind near southern Greenland.
OMI measurements on April 29 show SO2 emissions south of Eyjafjallajökull. High SO2 column amounts are observed SW of the volcano, probably due to light winds (indicated by the Keflavik radiosonde sounding) and reduced dispersion of the volcanic plume.
Aqua MODIS images of Iceland at 13:40 UTC. The left image shows a true color composite, while the right image shows a false color composite with MODIS bands 7, 2, 1 assigned to red, green, and blue, respectively.
Snow and ice show up as turquoise in the false-color composite, whilst warm clouds (comprised of water droplets) are white.
The water-rich Eyjafjallajökull volcanic plume is readily distinguished in the false color image in contrast to the surrounding cold (ice) meteorological clouds.
A reddish-colored hotspot is also apparent in the Eyjafjallajökull crater in the false-color image, indicating the presence of hot lava radiating in the 2.1 µm wavelength region covered by MODIS band 7. Image credit: MODIS Rapid Response System
OMI measurements on April 30 indicate another change in wind direction directing the SO2 plume from Eyjafjallajökull towards the UK.
Terra MODIS (left) and Aqua MODIS (right) images on May 1 show increased ash content in the plume compared to recent days. Credit: MODIS Rapid Response System
OMI SO2 measurements on May 1 show ongoing SO2 emissions from Eyjafjallajökull and a diffuse SO2 cloud over Scotland. SO2 column amounts in this cloud are low (~1 DU).
Terra MODIS (left) and Aqua MODIS (right) images on May 2 show continued ash emissions. Credit: MODIS Rapid Response System
Terra MODIS (left) and Aqua MODIS (right) images on May 3 show ongoing ash emissions. Credit: MODIS Rapid Response System
The above screen capture from the Vodafone webcam north of Eyjafjallajökull show ongoing ash emissions from the summit vent. Steaming on the lower flanks is due to an advancing lava flow interacting with glacial ice.
Using Aura/OMI measurements on May 4, the SO2 plume from Eyjafjallajökull can be traced from Iceland across the western UK and out into the Atlantic Ocean.
Resources for tracking emissions from the Eyjafjallajökull eruption:
Near real-time ash retrievals from MSG/SEVIRI (NOAA/NESDIS/STAR/CIMMS - University of Wisconsin - Madison):
EUMETSAT SEVIRI ash product (Iceland sector):
EUMETSAT SEVIRI dust product (Central Europe):
MODIS subsets for Iceland:
OMI near-real-time SO2 for the Northern Hemisphere:
OMI SO2 subsets for Iceland:
GOME-2 Absorbing Aerosol Index (AAI) for the London VAAC region:
CIMSS Satellite blog (SSEC/University of Wisconsin - Madison):
Norwegian Meteorological Institute (Meteosat data):
Observations of the volcanic ash cloud from the Cloud and Aerosol Imager (CAI) on the Japanese GOSAT satellite:
Multi-Angle Imaging Spectroradiometer (MISR) observations of plume height from NASA's Terra satellite:
RADARSAT views of the Eyjafjallajökull eruption (Canadian Space Agency):
Medium Resolution Imaging Spectrometer (MERIS) observations of the Eyjafjallajökull ash plume from Envisat (ESA):
London VAAC volcanic ash advisories and ash concentration charts:
Montreal VAAC products:
FLEXPART dispersion model output (courtesy of NILU, Norway):
Aarhus University plume dispersion model:
Fall3D model simulations (Barcelona Supercomputing Center, Spain):
Puff Volcanic Ash Tracking Model (courtesy of UAF-GI, Alaska, USA):
Forecast results for the Eyjafjallajokull eruption from the Unified EMEP model, updated daily (University of Oslo, Norway):
Operational forecasts by the Air Quality and Emergency Modelling System (Finnish Meteorological Institute, Finland):
Keflavik weather radar:http://en.vedur.is/weather/observations/radar/
Lightning strikes (Iceland):
Webcams (Faroe Islands):
Ash observations in the UK (Met Office):
Ash samples collected in Aberdeen (Scotland):
Reports of a Finnish military aircraft encounter with the volcanic cloud:
Reports of research flights to sample the volcanic cloud over the UK (UK NERC):
Report of volcanic cloud sampling via weather balloon over Scotland (University of Reading, UK)
The case for improved satellite sensors (in the words of IAVCEI RSC leader Fred Prata):