June 7, 2010
Today was Haviland and Lauren's first long data run. For the rest of June and July, almost every day that there is not terrible rainy weather, Haviland and Lauren will be taking data while during their work in the LIDAR room. Today had clear skies almost all day, except for a few wispy clouds around 7:00pm GMT. We ran EARL from 2:12pm GMT until 8:36pm GMT, when several helicopters started appearing. We stopped at 8:26pm GMT for a helicopter, and started the laser back at 8:29pm. Then at 8:36pm GMT, we had to stop again for another helicopter. Haviland turned off the "Save Data" button because the laser was not running because she did not know that, when the laser is turned off, the data automatically does not save. Therefore, when she turned the laser back on at 8:45pm GMT, the data was no longer saving, so she lost the data that would have been saved from 8:45pm GMT until 10:00pm GMT.
The wunderground.com weather website we use for our Raw METAR data said that there was a low aerosol concentration today. However, there were several airplanes. They did not seem to affect the data set, but if we want comparison from an airplane-free day to a busy-airplane day, then 06-07-2010 can easily be the busy-airplane day.
The wunderground.com weather website we use for our Raw METAR data said that there was a low aerosol concentration today. However, there were several airplanes. They did not seem to affect the data set, but if we want comparison from an airplane-free day to a busy-airplane day, then 06-07-2010 can easily be the busy-airplane day.
Notice how far the blue extends on the Depolarization Ratio graph below? That is what clear skies data will give you. Because the boundary layer was mostly clear and no clouds were present, nothing was there to impede the laser light.
Apparently, despite the clearness of the day, there was still something up at 12 km. The skycam picture, taken at 7:00pm GMT, shows clear skies and a bright sun. There is not a cloud in sight. So what could be at 12 km? The tropopause for this day is around 17 km. Planes generally flight either directly under or directly over the tropopause, so it does not seem like it should be a plane contrail. However, with such a clear day, perhaps flying so high is not necessary because no clouds need to be avoided. It is also possible that cirrus clouds could be up at that height, since there is a depolarization signal; however, if they are up there, they did not show up on the skycam despite the sky being otherwise clear.