30 August 1995
PH: I'm going to summarize what we've done today. Today was just one mission, which was a vertical profile over the NASA sunphotometer located in the Pantanal at 16.4[[ring]] south and 56.62[[ring]] west. We arrived at the site ahead of the ER-2 and we climbed to above cloud top, cleared the smoke and the altocumulus which was fairly extensive at that time. Climbed about 1,000 ft above it. Got good lidar measurements through the cloud and the smoke below and then we did a horizontal leg centered on the sunphotometer 10 miles on either side of the photometer at 14,000 ft in fairly clean air. We then descended and did a couple of runs back and forth. All of these runs are oriented east-west in the altocumulus cloud. That was at about 12,000 ft. We then dropped over the next hour or so or less 1,000 ft increments. So we first dropped to 10,600, then to 9,600 and so on down to 2,600 ft. and on each of those legs we were running first of all 5 miles on either side of the sunphotometer site but then, when Ken was informed that Cuiaba was going below minimums, we ran just 3 miles on either side of the sunphotometer site on the last few legs. But each leg took us directly over the sunphotometer. And then we did a pass, I think, after 2,600 ft, at 1,000 ft and then 500 ft. I'm not sure about the 1,000, but we certainly did 500 ft above ground, which is as low as we could fly; Art reckoned that the smoke base was a couple of hundred feet below that. Each time we went over the sunphotometer Ken marked the position and all instruments seemed to be working. I assume Ron got extensive chemical samples and Ray was getting all of the optical measurements. The Valero radiometers were working okay. I'm not sure about the CAR if that was working or if it's of any relevance today. At that point, although we still had maybe an hour and a half that we could have had on station, we couldn't use it because we had to return to Cuiaba in order to land under visual flight rules. I should mention that at the beginning of the flight, when we were at altitude, there was fairly extensive altocumulus. It looked like it anyway from on top. That moved off to the west, and during the latter part of the profile over the photometer the cloud was decreasing rapidly; it was probably only about 20% or less during the second half of the profile. So this should be a very good data set for comparing with the sunphotometer. The ER-2 passed over us. At least we assume it passed over us, we didn't have any contact with them again. They didn't call us, although they were asked to, but it was due to pass over us between 10:49 and 11:13 Local Time (Cuiaba time) going pretty much over the sunphotometer, and we should have been flying beneath it at that time. And then the ER-2 should have done another pass back, west to east, a little further north. So we should have good simultaneous measurements with the ER-2.
PH: Okay, Ray. Summarize your measurements today.
RW: Well, I took 41 "no-bags", 3 humidigrams, and single-scattering albedo based on the aethelometer. The nephelometer was very steady, held at about 0.88 the whole time through smoke, which I assume is working pretty good. Other than that it's pretty uneventful. Everything worked.
PH: What did the humidigraph show today.
RW: Flat.
PH: No growth up to 100% relative humidity.
RW: It doesn't go up to 100, it only goes up to between 80 and 85%.
PH: Oh, really. I thought it went up to 100?
RW: No, I don't think you want to try to saturate the inside of a nephelometer.
PH: Okay.
RW: The growth factors are based on, I think, 80% to 30% ratios.
PH: Okay. Could be that the smoke doesn't deliquesce until you get above 85%.
PH: Don?
DS: Today we took quite a few bag samples so I have quite a bit of CCN data. The CCN data looks actually pretty good up above the clouds and between the layers the CCN was very low and it increased as we got down into the smoke/cloud plume area. It remained pretty constant as it got lower there were some larger and larger particles so the channels 3 and 2 became more active. Channel 1 did not become active. It has stayed about the same in all the flights so far. We ran the lidar at the beginning for about an hour and 45 mins and got a pretty good profile of the cloud and smoke from about 14,000 ft down to ground. The lidar itself showed the layer of cloud and beneath it a pretty homogeneous mixture of smoke. Quite low down to the ground. That's about it, Peter.
PH: Okay. Jason?
JL: Overall it was kind of an ordinary day for CAR. The only positive is the eastern side of the sunphotometer site that if we could climb on top of it we should be able to do some reflectance study because the layer is very thick and the ground is not visible over that part of the world. The only problem at the beginning was the presence of altocumulus clouds that stop us from doing anything with the CAR.
PH: Yes. It wasn't a CAR mission but the Valero radiometers were all working fine. They should be useful for this study. Notice, Jason, that it would be very difficult actually to choose a characteristic surface area for where we were flying today. I mean there was some areas that were scattered trees and grass but there were other areas that were completely wooded. Other areas that looked pretty yellow and dusty. I don't know how one would define a characteristic surface for that region.
AR: True.
PH: Okay. Go ahead Art.
AR: We took off from Cuiaba in clear conditions and had a non-turbulent flight.
PH: Art, you say we took off in clear conditions? It was pretty smoky.
AR: I meant cloud-wise. Thank you. There were no clouds overhead at Cuiaba and then we seemed to catch up with a patch of altocumulus that had been overhead of Cuiaba in the vicinity of the photometer. That continued to move off toward the west and the cloud cover thinned in time. We had tops at 11,900 to 12,200 ft in two different penetrations. The maximum cloud depth that I observed was less than 100 ft, and during the photometer studies the clouds were less than that, probably ranging from 50 to 25 ft in depth and they were barely clouds. On top of this cloud layer we had a separation clear zone followed by another very, very thin haze layer up around 14,000 ft. I don't have the exact height of that but it's a scenario that we have seen before and there did seem to be some kind of source for that. A possible source on the horizon well over 100-150 nautical miles toward the east. It seemed to be thickening that way more than due to perspective, and there seemed to be less of it to the west which would tend to indicate a source region.
PH: Keep everything running as long as we can. We're still in the smoke. Go ahead Art.
AR: I just wanted to mention that we seem to have no boundary layer convection until we were down to 2,000 MSL or the photometer site. That was the first time we started to get any turbulence and also, with the lower haze layer, was pretty much homogeneous. I saw no structure within that from the top near 12,000 ft down to the surface. There may have been a base 200 ft below our lowest pass over the photometer site. On the way back we did start to pick up some convection at higher levels. However, I don't know if this is a time effect or terrain effect down there but we started getting bumps at 5,000 ft so. But over the photometer the boundary layer convection was not higher than 2,000 ft.
PH: Jack.
JDR: Everything worked okay except for the radio altimeter and of course the DMPS is still not working. Besides that everything else is fine.
AR: Can I just add that this is the smokiest day that we've worked so far, from a visual standpoint.
PH: Okay. As we head back to Cuiaba we've climbed to 5,000 ft so that should be another profile through this smoke, not to the top, but at least in the lower layers.
RF: Okay, Peter. I think everything went great except for the last set of filters we got out of sequence here when we cut the legs short, but we loaded up all around the other legs so I think we did fairly well on this one. And then on the way back here we are just sampling cascade impactors and Nuclepores for Jeff.
PH: So you missed the 500 ft.
RF: Well, I was collecting 2 bags per filter and then so each filter was the combination of two levels but we ended up on an odd leg there so instead of changing filters on the last one I just added a third bag to the two previous ones, so we loaded up that last filter by an extra bag.
PH: Yes, I thought we were going to get one more level. I thought Ken had told me one more but he broke off.
RF: No, I had sort of set it up for an even number of levels and then we ended up on an odd number.
PH: So, say again, what did you get on each pass all the way from the top down?
RF: The full complement of Teflon, Nuclepore, quartz.
PH: Okay. Great. That should be a good.
AR: I haven't seen clouds since we left the photometer site.
PH: I assume all this smoke today was fairly long range transport. Some may have come from the Cuiaba area, but it's probably the usual amount of burning going on around here. The airflow, I think, would have brought it down to the Pantanal but a lot of it must have come from further north.
AR: That's correct. I haven't seen a single fire out there, although we don't have any visibility. I don't think we even went through anything that looked like a plume did we?
PH: No, I don't think so. We had a little perturbation on the instruments at one point but I think it was our own exhaust.