Spaced Out ::

Nobody can have missed the massive explosion (supposedly the largest peacetime fire in Europe) that rocked the Buncefield oil depot in Hemel Hempstead, UK, this week. I actually live within 10 miles of the depot and felt the blast wave early on Sunday morning. The depot is sited close to a motorway within an industrial estate. And although there is residential housing close by, the area is primarily light industry. Safety concerns rapidly moved from those close by, to the effects of smoke as they rapidly covered London and the south-east. Sunday was an unusually windless day and, due to a winter temperature inversion, the effects of both the sound of the blast and the pollution, were concentrated at lower altitudes and not dissipated.

Satellite imagery has played a key role in monitoring the spread of smoke and two key sensors have been employed:

1. MERIS - mounted on board the European Space Agencies ENVISAT, MERIS is a hyperspectral system with a 300m spatial resolution. With a rapid 3-day revisit capacity it is very good at monitoring a variety of environmental phenomena.
2. MODIS - mounted on board NASA’s TERRA and AQUA satellites, MODIS offers daily revisits at 250m spatial resolution and, because there are two satellites, two images per day are available (AM for TERRA and PM for AQUA). One of the key sites for environmental monitoring is the Rapid Fire system. Near-real time imagery is delivered to the site for download and use. If you look through the archives for Sunday (11th) and Monday (12th) there are images of the fire available.