28 August 1995
PH: This was basically a couple of aerosol-cloud interaction studies. One near the beginning of the flight, but I don't think it was too successful. And then one at the end of the flight, which may have been better. Between those two studies we looked at a couple of plumes fairly low down and tried to get emission factors. The second fire being the better one, which we sampled fairly extensively maybe three or four distances downwind but all quite close to the fire. We tried to follow a brownish-orange plume that was coming from a sort of circular fire that had some flaming combustion at the beginning, died down about half way through our study, and then came back up again towards the end of our sampling the smoke. So it was fluctuating quite a bit in intensity and it was that same second fire that produced the smoke going into the cloud that we did some aerosol-cloud interaction studies on at the end of the flight. Apart from those, it's been generally regional smoke. Not too many fires around today, but Art said he counted about 20 odd, mainly small. Okay, Art, why don't you summarize.
AR: Okay. This is a day where we had scattered cumulus humilis. None of which were as much as 1,000 ft thick with bases at 10,000 to 10,300, tops about 10,800 and clear above. No indication of higher haze layers, and this was generally under easterly flow overall, clouds that were drifting at cloud level from the east to the east-northeast, and a bit of an Ekman spiral in the boundary layer. The winds light and variable really in the boundary layer seemed to be switching all over it, and we saw the haze gradually increase during the period of the flight. When we took off I noted the base of the regional haze layer was about 800 to 1,000 ft above sea level. It appeared a little bit higher than the clearest bases that we've seen underneath the regional haze in the past.
PH: Okay, Ray. Summarize.
RW: The OEC worked well in the second fire. I got some pretty good data there. Appears to be fairly dark smoke. There may have been some altocumulus electrooptical activity, though that will be hard to tell at this point. A little bit later it will be easier. Took a lot of "no-bag" samples and all the equipment seemed to work.
PH: Okay, Don.
DS: Okay. Well, had the lidar running a couple times here. I've got some information on that. TDDR has been going. I haven't seen any problems with that. The CCN functioned fine for the entire trip. Beyond that everything seemed to go good back here.
PH: Now the lidar, Don. In what part of the flight did that get switched on for the first time?
DS: It got switched off, I wrote the times down.
PH: Switched on.
DS: Oh, switched on. Shortly before we started going across the fires the first time.
PH: The first time?
DS: Yes.
PH: And then it got switched on again. It was switched on when we were climbing on this last cloud study, wasn't it, up until 12,000 ft it was still on?
DS: Yes. It's going right now. I need to get back and turn it off in a second.
PH: Well, keep it on until we get down to our minimum altitude. Jeff?
JR: Yes.
PH: Okay. Jeff, summarize the chemistry measurements you made today.
JR: Got 8 Teflon filters and 4 quartz. We got a couple of decent samples for emission factors, but we never really got a good sample in the heart of the plume. We pulled 3 RAS cans, 2 in the smoke and 1 background.
PH: Okay. Can you be a little more specific about which of the two fires you got your various samples in?
JR: I think we got 1 RAS can at the source of each one of the two fires we looked at.
PH: Okay, and the Teflons?
JR: Yes, we got Teflons on all of them plus we also got a total of 3 Teflons when we looked at that plume going up into a cloud at different levels.
PH: That was the last one we looked at, that last aerosol-cloud study.
JR: Correct.
AR: I would just mention. We just passed over a couple of fires in which the plumes were going in opposite directions. The fires separated by about 2 or 3 miles.