LTI Report, 29-June-2000


Here is the APS data (pdf file) from our first C-130 flight with the LTI. It was the first time most of the instruments were turned on, so some flowmeters had not been recalibrated and this needs to be taken as very preliminary. Also, the concentrations of large particles in Colorado is not that great (that's why we're headed for St. Croix), so the counting stats in the large size ranges contribute significant uncertainty.

However, even with all that uncertainty, when the three APSs ran on a common source of particles (the CAI), they agreed very well in the 1-3 um size range. The divergence above that may well be due to the lack of 5-10 um particles in the CAI flow, which lead to even worse counting statistics.

Contrast that with the bottom graph, in which the concentration from the LTI is clearly larger in the 1-3 um size range (by about the 20-50% we found in PASIN) and by more than an order of magnitude at 10 um. This is exactly what one would predict from knowing that the LTI maintains laminar flow. Needless to say, we've very excited that our first results appear to confirm our faith in this technique.