July 9, 2010
Today, Haviland started the data run at 12:35pm GMT to make sure that the computer was working after it having not booted up the day before. The atmosphere was fairly clear, and no clouds were obviously visible. Apparently, though, there was more in the sky than we could see with our naked eyes or the skycam.
Up at about 10 kilometers, there was a hazy signal from what seems to be a very thin cirrus cloud. The object lasted for about an hour, so it was probably not a plane contrail, which we do not tend to see for long amounts of time. The Depolarization Ratio graph shows returns at the same height and time, which suggests that there was a strong ice concentration. Because of the ice and the high altitude, the object was probably a cirrus cloud.
There was also an object at about 8 kilometers from 2:30pm GMT until 3:00pm GMT. It had slightly stronger returns on the Range Corrected Backscatter graph, but weaker returns on the Depolarization Ratio graph. The tropopause today was at 15,000 meters, so the 8-kilometer object was probably not an airplane contrail. The object was probably a cirrus cloud that, because of its lower altitude than the 10-kilometer cirrus cloud, had lower ice concentrations and higher water concentrations. As for why the signal is slightly stronger on the Range Corrected Backscatter graph, it was probably just a thicker cloud.
Up at about 10 kilometers, there was a hazy signal from what seems to be a very thin cirrus cloud. The object lasted for about an hour, so it was probably not a plane contrail, which we do not tend to see for long amounts of time. The Depolarization Ratio graph shows returns at the same height and time, which suggests that there was a strong ice concentration. Because of the ice and the high altitude, the object was probably a cirrus cloud.
There was also an object at about 8 kilometers from 2:30pm GMT until 3:00pm GMT. It had slightly stronger returns on the Range Corrected Backscatter graph, but weaker returns on the Depolarization Ratio graph. The tropopause today was at 15,000 meters, so the 8-kilometer object was probably not an airplane contrail. The object was probably a cirrus cloud that, because of its lower altitude than the 10-kilometer cirrus cloud, had lower ice concentrations and higher water concentrations. As for why the signal is slightly stronger on the Range Corrected Backscatter graph, it was probably just a thicker cloud.
Hazy clouds with small returns
At about 3:30pm GMT, there was a hazy cloud u pat 3 kilometers. It lasted for almost an hour before completely dissipating. The cloud looked so thin that we were not sure whether it was at a high altitude or whether it was, plainly, just a thin cloud. The Range Corrected Backscater graph seems to suggest that it was a little bit of both. The signal was not very strong, so the cloud must not have been very dense. This we can plainly see with the skycam picture of the event, to the left. However, the cloud was also up a bit beyond 3 kilometers, which is significantly higher than the usual 1-2 kilometer clouds that we get every day.
However, the most interesting part of our data is not, surprisingly, the cirrus clouds that we did not recognize were there, nor was it the possibly thin, possibly high clouds that we saw as scattered wisps in the sky. The interesting part is: what happened at 5:15pm GMT? There is a strong return on the Range Corrected Backscatter graph of something happening between 500 meters and 2 kilometers. It seems almost as though there is a direct vertical line of returns coming from that time slot. We did not place a cloud mask on during that time, so we must not have been too worried about what we saw on the screen in real-time. But there definitely looks as though there was something very thick for only a short while.