Tuesday, 19 July 2011

Chasing Plumes from Fires in North Western Ontario

In order to fit two flights into the day we had to have a fairly early start so power was on at 7am with take off at 11am local time. After take off we set off in a north easterly direction from Halifax, heading for Stevenville at 25,000 ft. Before long we started to see some structure in the carbon monoxide (CO) indicating that we might be seeing some pollution. Dave who operates the proton transfer mass spectrometer (PTR-MS) reported he was starting to see some acetonitrile, a tracer for biomass burning, and the LIF saw increased levels of PAN. The core chemistry operators, Seb and Steph, reported that the methane seemed to show a correlation with the carbon monoxide, as did the HCN trace (another indicator for biomass burning) from the CIMS instrument. This news was very welcome showing that all indicators were suggesting we were in the plume we were hoping for.

The original plan had been to drop down to a lower altitude for the next run but since there was a cloud layer below us it was decided that we would stay at 25,000 ft and fly back through part of the plume. Here we saw the highest concentrations that we had seen so far and in fact the carbon monoxide concentrations shot up to the highest value that Steph has ever seen on the aircraft except when we are sampling next to the generator at the airport. Data analysis and investigation post flight will tell us if this is real but it is definitely exciting stuff. As we turned to head NNW we descended to 5000 ft at 1500 ft/min but once we were down there nothing was really happening so after a short run we ascended again to 25,000 ft for our approach to Goose Bay. Unfortunately on this run we saw very little action.

The weather at Goose Bay was not good; it was both wet and windy and there were little rivers on the runway. We did however see a very interesting aircraft. It was a CL215 Snooper which is an amphibious firefighting aircraft. Apparently it scoops up water from the surface of the sea or lakes and then squirts it out over fires. Very cool!

Picture taken at Goose Bay of the CL215 aircraft

We took off from Goose Bay around 16:30 and headed NW. There wasn't much to see where we had expected to find the plume so we tried different headings and altitudes but we just couldn't locate our plume. The guys on the ground, particularly Mark Parrington were brilliant. They sent us satellite images, predicted altitudes of carbon monoxide along our intended track and pretty much anything else we asked for. Towards the end of the flight Dave on the PTR-MS reported that although he wasn't seeing any biomass burning tracers he was seeing high concentrations of some interesting compounds including terpenes. This was confirmed by the GC-MS measurements and also some elevated CO. After this dropped off, on our approach to Halifax we started to see indications that we were getting back into a biomass burning plume. This had not been predicted by the models or indicated by the satellite measurements so again, an interesting find, just unfortunate it happened as we were running out of fuel and crew hours and so couldn't investigate it further. We landed in Halifax just before 10pm, a long day but hopefully some good science will come out of it.

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