Saturday, 23 July 2011

Update from the Guys at DGS

Post written by Kaja Rotermund

Here at the DGS (Dalhousie Ground Station), our daily activities aren’t quite as adventurous as those for the Atmospheric Research Aircraft (ARA) and its flight crew, but we still have some exciting news to share. The most interesting of which is the data we were able to collect over the last few days (July17 – July21).  We were anticipating the arrival of boreal biomass plumes, but IASI Satellite images for the evening of July 20th indicated that it was possible the plumes would bypass us to the north completely. We were therefore pleasantly surprised and excited when the satellite images of the following morning showed a shift in direction of the plume, bringing it over Halifax. We got even more excited when our lidar plots showed high levels of backscatter congruent with dense plumes.  We observed the plume to be below 2km altitude and it stayed overhead for just about a full day. Due to the low altitude, we are very hopeful that the other instruments at DGS were also able to collect data for this event. When looking at the sky from Halifax at this time, a slight haze was definitely visible, which we are convinced must have been the extremely low aerosol plume.

The lidar recorded two sections in the plume. The first plume, which arrived shortly before midnight on the 20th was so dense that water vapor condensed onto the aerosol, forming a cloud. The aerosol is still visible along the outer edges of the cloud though. After a slight break in aerosol density at around 0800UTC, a second plume equally as dense, but with no cloud formation arrived. Unfortunately heavy clouds and fog rolled in after that making it necessary to shut down. Nevertheless, we are still very happy with the measurements we took and are looking forward to comparing our data with those of the other instruments on both the ground station and from the ARA.

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