Satellite Image of latest Ash Cloud
Meteosat Second Generation (MSG)
MSG images are monitoring for the presence of volcanic ash emission in the vicinity of Iceland using infrared data from the Meteosat Second Generation (MSG) satellite. Because cloud particles and volcanic ash particles interact with the infrared radiation in different ways, data at several different wavelengths can be combined to identify the main ash plume, which, when present, would be shown as yellow and orange colours in the images. However, it should be noted that it is only the thicker parts of the plume that are able to be detected by this method. In addition, the ash plume is often masked by overlying high cloud and therefore might not appear in the satellite image.
Flights in Scotland have been cancelled by a regional airline as volcanic ash continues to head towards the UK.
Loganair, based at Glasgow airport, has cancelled 36 flights on Tuesday as the Civil Aviation Authority (CAA) warns that disruption cannot be ruled out.
Analysts expect the ash cloud from an Icelandic volcano to reach Scotland and Northern Ireland by Monday evening.
The event comes a year after ash from the Eyjafjallajokull volcano spread across Europe, causing huge disruption.
Andrew Haines, chief executive of the CAA, said: "Our number one priority is to ensure the safety of people both onboard aircraft and on the ground.
"We can't rule out disruption, but the new arrangements that have been put in place since last year's ash cloud mean the aviation sector is better prepared and will help to reduce any disruption in the event that volcanic ash affects UK airspace."
A Loganair spokesman said Met Office forecasts indicated that a high density of ash would be present in large parts of Scottish airspace throughout Tuesday, clearing into Wednesday morning.
It has cancelled almost all flights on Tuesday and advised customers due to travel to contact them to rearrange flights. Only inter-island routes in Orkney are unaffected.
The UK's air traffic control service, Nats, said volcanic ash was forecast to affect parts of Scotland between 1800 BST and midnight on Monday.
Services may be affected from Barra, Benbecula and Tiree.
The Met Office, which runs Europe's Volcanic Ash Advisory Centre, earlier said there was a possibility of ash moving across the UK towards the end of the week.
But a spokesman said the weather was much more changeable than at the time of last year's eruption and there was a lot more uncertainty.
The CAA said ash levels would be graded as low, medium or high, and airlines would be notified if levels reached medium or high.
Airlines would then consider whether to fly, according to risk assessments already carried out, the CAA added.
NEW technology that could minimise future disruption to planes from volcanic ash was unveiled today by budget airline easyJet. The carrier will be the first airline to trial a new "weather radar for ash" system called AVOID (Airborne Volcanic Object Identifier and Detector).
The system involves placing infrared technology on to an aircraft to supply images to both the pilots and an airline's flight control centre.
These images will enable pilots to see an ash cloud up to 62 miles (100 kilometres) ahead of the aircraft and at altitudes between 5,000ft and 50,000ft.
This will allow pilots to make adjustments to the plane's flight path to avoid any ash cloud.
Millions of passengers had their travel plans wrecked when airlines had to scrap thousands of flights in recent weeks due to Icelandic volcanic ash.
The ash is back. Fresh volcanic activity under the Eyjafjallajokull glacier in Iceland has resulted in a fresh ash plume being pushed about 5.5km (18,000ft) into the air.
Airports in parts of Scotland and Northern Ireland closed from 0700 BST because of risks from volcanic ash, the Civil Aviation Authority has said.
Glasgow, Prestwick and Derry are likely to be closed all day, while there are plans to shut Inverness in the morning only, and Belfast in the afternoon.
The CAA advised air passengers to check with airports before travelling and warned the situation was changeable.
Last month, volcanic ash clouds from Iceland grounded flights for six days.
The situation in the skies has been changing hour by hour, meaning the picture for air travellers is unclear.
Dublin Airport will also close from 1100 BST until further notice.
Forecasts show the 60 nautical mile buffer zone imposed around high concentrations of ash is close to some northern airports.
Belfast International 1300-1900
Belfast City 1300-1900
All times in BST. Source: CAA at 0200 BST
However, the latest advice issued by the CAA at 0200 BST said airports in Edinburgh and north-west England could safely stay open on Wednesday, despite the proximity of the ash.
The CAA says the South East of England is unlikely to be affected on Wednesday.
In a statement, the CAA said: "The situation remains changeable, so passengers expecting to travel from airports in Scotland, Northern Ireland, the North of England and north Wales should contact their airlines to check whether their flight is operating."