Thursday, 21 July 2011

Highest CO yet and smoke in the cabin!

Post by Andrew Rickard

Today the ARA flew two flights (B622 and B623) with a refuel in Quebec in order to intercept some intense plumes forcast nearer to the fire area of interest. B622 was flown as planned to the west then back into Quebec in excellent flying conditions. There was substantial evidence of biomass burning in discrete layers around 13-15,000 ft. Discrete thin layers of brown haze were clearly observable (picture to follow). We observed CO up to 1 ppmv in one layer, a new record! The Manchester CIMS and UEA PTRMS were also observing high levels of acetonitrile, a fairly unique tracer of biomass burning. At one point a distinct faint smell of woodsmoke was discernible within the cabin!

Between flights, the ground power to the aircraft in Quebec failed, and for a while it looked like we might have to cancel the second leg. However, with all hands to the pump and some quick thinking by the onboard scientists, disaster was avoided and the majority of the instruments were quickly back up and running close to normal, delaying departure by only 30 minutes. B623 original flight plan was altered owing to weather, returning (via US airspace to avoid a line of storm clouds and lightning strikes) to the Halifax area, with profile runs NW of Halifax in order to capture the extent of the biomass burning (BB) plume area. We then recieved some very interesting data from the Dalhousie LIDAR in downtown Halifax of an intense BB plume directly over Halifax itself. We quickly decided this was an opportunity not to be missed and so the quick thinking pilots performed spiral ascents and descents above Halifax up to 25,000ft in conjunction with Dalhousie Lidar (quite interesting for those onboard!). Both flights were highly successful and will deliver a multitude of science. It is credit to the enthusiasm and professionalism of both the full team on board G-LUXE (the code for the aircraft), and of the local Air Traffic Control Services in delivering a very high quality sortie despite substantial adverse factors.

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