17 September 1995
PH: Okay. I might as well summarize what we've done so far on this flight. We started off by sampling some smoke from a reasonable size burn with some flaming combustion. I didn't get a good view of it, but apparently it was pasture producing some brown smoke, flaming, and moving into some forest area. We got emission factors on that. Then we did a little bit of sampling of the complex cloud system that that fire was producing, but it was so smoky and such a big cloud that it was difficult to do any systematic sampling of it. We then climbed up in that general area to sample smoke layers at various levels being detrained by the clouds. According to Ron, the smoke layers at these higher levels weren't there this morning. So it was probably old smoke that had been thrown up by the clouds. We sampled several layers of that. We moved around the cloud produced by the fire that we had sampled earlier. Got some good samples of detrained air from that. Went up to 14,000 ft and still saw some smoke near cloud tops at that level. The tops of the clouds were going several thousand feet above that and I would have liked to have gone up to sample any ice in the tops of those cloud (at 14,000 ft we had a temperature of -0.3[[ring]]C), but Air Traffic would not allow us to go higher. Then we descended down through various smoke layers to 9,000 ft. We are now heading out at 9,000 ft to see if we can spot any of the large fires that were going this morning.
There's a lot of cumulus activity here this afternoon and certainly most of the prominent cumulus are probably produced by fires beneath.
Ray, do you want to summarize so far?
RW: Let's see. I took no-bag samples about 20 of them in cloud and out of cloud and below cloud. Got humidigraph samples both in and out of cloud and they look pretty good. The A3 showed an asymmetry factor to the aerosol in some of the samples, particularly the cloud samples, which was surprising. Also, got good OEC data on the fires.
PH: Don? Don, let's put the lidar on here.
DS: Okay.
PH: We should have switched that lidar on earlier if I'd have been on the ball when we were at 14,000 ft. At 9,500 ft here, I can't see the ground beneath us.
What do you see on the lidar?
DS: Well, I see some smoke layers below us. I seem to see some very small fires or small fires also coming up from the ground.
PH: Okay. Why don't you summarize what you've done so far?
DS: The CCN has seen some variations in what was coming up below going into cloud and exiting. The larger CCN tended to have been removed and in some cases the smaller CCN have either remained the same or become a little larger.
PH: Ron, how about summarizing?
RF: Okay, summarizing. Let's see. Things were completely different out here this afternoon than they were this morning. Much more ambient smoke. Much bigger cumulus. Lot more ambient background it seemed. And the first fire we did today for emission factors I think that was a pretty good sample. After that, we sampled one, two, three filters for cloud processed smoke at 11- to 14,000 ft and I think in each of those cases we can be fairly certain that that was smoke that was pumped up there today because we flew all through this region at 7-, 9- and 11,000 ft today and there were no layers or, you know, no variabilities whatsoever in the ambient aerosol. So, that's most certainly recent stuff. We got good emission factors on the last sample here where we did the brush fire a few minutes ago. Good DMPS data all day and a lot of cans.
PH: Okay. Good. Two good flight today. I think our best smoke-cloud interactions studies were yesterday afternoon's flight and these two flights.
RF: Yes, I think, you know, it was a fairly confused situation today, but there is just no way that smoke could have gotten up there if it wasn't pumped through those cumulus clouds. So, it will be interesting to see if there is anything we can say about it physically or chemically that is unusual about it. But, no doubt it got there through those clouds.