7. IN-FLIGHT SUMMARIES FOR EACH CONVAIR-580 FLIGHT IN KWAJEX/TRMM

Complete typed transcriptions are available for all of the in-flight voice recordings (made by crew members on the UW Convair-580) in KWAJEX. These recordings provide detailed information on what occurred on each flight. However, because of their size, these transcriptions are not reproduced here. Instead, given below are typed transcriptions of the summaries crew members recorded aboard the aircraft toward the end of each flight. Although subsequent data analyses might reveal important aspects of a flight, and of the data collected, that are not mentioned in these summaries, they do mention most of the main features of a flight and they have the advantage of on-the-spot spontaneity.

PH: Ricky, why don't you summarize what you've done on this flight and can you summarize also for Naoki or should he do his own?

PH: That is as expected.

PH: Which is what?

RS: It is 0.5 ppm is the detection limit and average levels are around 0.1 ppm. The ozone is working properly.

PH: Is or is not?

PH: Tell us what you did on the flight.

RS: Basically I monitored the performance of the instruments. We also checked the bag house. We cleaned it by pumping air through it and then releasing it, but it seems to have a potential leak or something because we're getting more air out of it than we should. We'll have to check on that.

PH: Okay. Is that it? Anything more to say?

RS: I think that's it. I'll get Naoki, one second.

1:38 AM

NK: This is Naoki.

PH: Would you summarize for the tape what you did on this flight.

PH: Okay. So you're going to have to look for leaks.

NK: After landing I should look for leaks.

PH: All right. Do you want to say anything else about what you did or is that it? Where did you take your sample, at what altitude?

NK: I didn't memorize the altitude, but I memorized the time so I can recover it.

PH: Okay. In future you might just want to make a note of the altitude and the time on the tape.

NK: Yes. In the display in front of me, there is no indication of the altitude or anything.

PH: Yes, but you can go to one of the text displays and read the altitude. There is one at my station and several other stations.

NK: Okay. I'll do it.

PH: Would you ask Ray to come on the headset?

1:40 AM

PH: Don, would you like to summarize your impressions of the flight, what worked and what didn't, and what needs to be looked at.

DS: Okay. The biggest triumph of the flight is the HVPS. We worked on it until about 11 o'clock last night and we got it working and it is fixed. It worked fine. The FSSP-100 worked pretty well this flight. It still has some dropout problems. We're trying to figure out exactly where the intermittence is. I reset it once and it works fine for the rest of the flight. We'll keep our eye on it until we can catch it and figure out what it is doing. The biggest problem that I've run into is the JW 400 Hz power supply died so we're going to have to try to fix that. Once we get that fixed it will be working again. Maybe we'll see if we can get 400 Hz power from someplace else. If that becomes a problem, we'll see if we can convert it to 60 Hz.

PH: Anything else?

DS: That's all that comes to my mind right now.

PH: One of the most important things is to get the time on the forward video.

DS: Oh, thanks. Yes. That shouldn't be too big of a deal. I just have to hook it in.

PH: Okay. Is Ray there now?

1:44 AM

RW: Yes.

PH: Would you summarize for the tape?

RW: Got some problems. The CN counters still have some problems with the inlets. I think we know what to do and I'll do it when I get back. But more importantly, the nephelometer looks like it has water in it again. There was water coming out of the instrument case, the control unit, which isn't good. The absorption unit seems to be working. It's mainly the nephelometer that is the problem.

PH: Where is the water coming from?

RW: I have no idea. I just noticed it was coming out so I turned it off about 12:15.

PH: Okay. So the CN measurements are not reliable for this flight?

RW: No.

PH: The CNC3 seemed reasonable to begin with. They were fairly low in the 400s and 500s.

RW: It's very low and stays low all the time. I think it is out of butanol.

PH: Well, actually it got very high later on in the flight when we were at altitude it went up to about 1,500 or something.

RW: Yes, but not compared to the other two. The other two read about the same and they were quite a bit higher.

PH: Do you think any of them were working?

RW: I don't know. We'll test them when we get on the ground.

PH: Okay. Art.

AR: Go ahead.

PH: Why don't you summarize?

AR: Flight 1783 was intended primarily to be a calibration with the rawinsonde. Today's weather was an approach of an easterly wave, which meant it was highly disturbed. We took off during a lull in the shower activity with middle broken clouds and an overcast altostratus layer. Just to the east of Kwajalein was a mesoscale convective complex. As we took off, the rain from that was reaching the end of the runway. Ultimately as this moved in, it turned out to be very strong and produced lightning at Kwajalein, which postponed the rawinsonde launch and the planned calibration spiral with the sounding from 11:00 AM until 12:00 noon. During the interim, we circled and sampled some cumulus clouds out away from the convective complex and at that time discovered the CPI seemed to have some water on it. We decided perhaps that finding the dry slot indicated on the 12 Z sounding…

AR: It might help the situation, but Kim Weaver didn't believe that it would because the condensation was on the inside of the probe within the seal and so we abandoned that and decided to fly in some rain, a stratiform rain area. It allowed Kim to do some further checks of the CPI. After doing that, the cell at Kwajalein began to move away and the stratiform region was (end of tape, side 1). At 12 Z we went back to Kwajalein and did a "touch and go" essentially and then followed the sounding up to 20,000 ft with visual sightings all the way up to about …

DS: Art, go quicker. We're running out of tape.

AR: Okay. After that we sampled the stratiform region that followed the convective region precip at Kwajalein. We did that until the end of the flight. That was following the calibration portion of the flight. I think that's most of it.

PH: Okay. That was followed by a couple of runs between Point A and B given to us by TRMM Ops and then between Point C and D by TRMM Ops. They are two different altitudes in this widespread stratiform cloud and precip. Things I noted that need to be looked at are time on the video, still no JW on the text readout, text readout (not at my station) crashes frequently. IR seemed to work at the beginning of the flight but not toward the middle or end. It was very erratic all over the place. As Don mentioned, the inverter went out on the JW. So that's about it. It was actually a pretty successful first test flight. We had very good communications with TRMM Ops. The pilot's radar has gone down so we will have to have that worked on. That's about it. Coming into land at Kwajalein.

No summary given on tape.

6:44 AM

PH: I'm going to summarize this flight.

The only part of the two goals that we achieved was to do some coordination with the DC-8 over one flight track when the DC-8 was above us. It was called line 6. We went together backward and forward between Points A and B on line 6. Point A was at 8°05'/168°02' and Point B was at 8°08'/167°34'. We did that below cloud base, at 500 ft above cloud base, at 4,000 ft altitude, and then at pressure altitude 8,000 ft. That was four runs backward and forward. The final run at 8,000 ft was not completed back to Point A because prior to its completion TRMM Ops informed us at 06:15 that they wanted us to cutoff the flight because there wasn't much precipitation around. The clouds were dissipating. At that point, the DC-8 headed back. We decided to continue to complete our profiles up through the clouds we had been working so we did further penetrations at 11,000, 14,000, 17,500 and 19,800 ft. At the highest altitude the cloud was collapsing on us. It actually wasn't all the same cloud. At some point, which is recorded on the tape, we broke away from the original cloud, which had collapsed, and continued to climb and do penetrations of another cloud that was similar to the cloud we had previously sampled during its raining stage. We're now heading back. TRMM Ops decided not to try to do the flight beneath the satellite today because of lack of activity out here and also the fact that our radar is down and the DC-8 will not fly at night. The Citation, as far as I know, is not yet up.

Is anyone else on the headset at the moment?

AR: Yes. I'm here, Peter.

PH: Why don't you summarize. We don't have too much time, but a brief summary.

AR: Roger. I understand. You covered it pretty well.

Cloud bases were running around 1,000 ft and again about +25°C. It was a non-disturbed day. Light and almost variable winds. No white caps. Tremendous horizontal visibility at the surface probably on the order of 100 nautical miles and the expected increase in activity did not materialize. We climbed through this row of clouds that Peter was mentioning in increments. At least in the upper portions, beginning around 8,000 ft in 3,000 ft increments until 14,000 ft. We went from 14,000 ft to 17,500 ft and we changed clouds at that point to capture the early life cycle of the clouds here. When they reach that level because the original clouds had dissipated almost completely by that time so we picked a new cloud. The purpose for that was to get hold of the droplet spectrum before the ice and warm rain developed. I wanted to make a note of that. We did have a visual contact with the DC-8 in their contrails and I was able to make out the plane so we probably will be able to do that quite often and verify where they think they are. I guess that's about it.

PH: Good, you filled in my gaps. Do you know if the HVPS was working okay?

DS: I believe it was. What's the ETA until we land? I have to give these guys a few minutes so we can shut stuff down nicely.

PH: What's the ETA, Ken?

KM: 10 or 12 min, Peter.

PH: Okay. So the CPI was working okay and we believe the HVPS was working all right. It should have given us some nice measurements in the showers we went through earlier on in the flight. As far as I could see the PMS 2-D and 1-D probes were working. The big success on this flight, for which we owe Don and Grant thanks, is that the DMT, JW and the FSSP were all up and working. The DMT and JW looked very nice in correspondence. The DMT and JW responded very well together. The FSSP responded also with them but was a little flat and not hitting quite the peak values that the other two were reaching. But a good correlation, if not absolute values. Is Chris Bellows on the line?

CB: Yes. Here.

PH: Summarize Chris.

CB: Not much to summarize. The AMMR appears to be running smoothly. No real problems to report.

PH: Okay. Do you actually see a signal when we're going in the showers? Could you see that you were recording good data?

CB: Yes, for the most part, there was good data coming through.

PH: So just earlier on in the flight when we were going through a few heavy showers. Do you get anything that's useful or only in showers?

CB: Mainly within the showers.

PH: Okay.

AR: We have a pretty strong cumulus turret here in about 25 s.

PH: Okay. Is Ray on the headset or Ricky?

RW: Yes. I'm here.

PH: Okay. Summarize Ray.

RW: The CN counts are unreasonably high and it maybe related to the fact that the TSI 3022 works on the ground but fails in the air when there is differential pressure across it. There maybe leakage of cabin air into it that's getting into the inlets. It's somewhere behind where the nephelometer taps in, which is the first one off the plenum, because it's fine. I don't know. We may have to test that at altitude in some smoke.

PH: Which one do you think is working okay, any of them?

RW: I think they are working.

PH: Which ones are providing reliable readings?

RW: Well, they are reliable readings except it's probably not outside air.

PH: That's what I mean by reliable outside air.

RW: Not on this flight. I think the last flight was okay.

PH: You don't think any of the CN counters were reliable on this flight?

PH: They're all showing high values like that so they must all have a leak?

RW: If it's leaking into the plenum, then we'll see that same air.

PH: Okay. What about the PSAP?

RW: It seemed to work okay.

PH: Real low?

RW: Yes. Real low, down in the noise.

PH: So you haven't seen anything high like you saw in the first flight?

RW: No. The same with the nephelometer, it's all low.

PH: Okay. That's expected. Ricky. Will someone get Ricky or Kaneyasu?

NK: I'm here.

PH: Say what you did on the flight.

NK: I took a bag house sample at about 0.9 kilometers height, but it seems to be leaking again. I thought that the cause of the damage to the bag house was the incoming shock of the outside air from the cruising speed. Then I showed them the opening period of the bag connected to the outside of the inlet, but I showed it to the 5 s switches, 1/4^th of the recommended body, but still there is some damage in the bag house so there is another reason. I think it is something to do with the pressure difference when the bag switches on and off. I'm not sure. I should check it later.

PH: Okay. Would you put Ricky on?

RS: Peter.

PH: Yes.

PH: Okay. Good. Don.

DS: On this flight things have worked fairly well. The FSSP, JW and DMT probes have already been mentioned. We're having a little problem with our auxiliary processor right now. Grant and I are going to try to get that working. It maybe heat related. It maybe crack related. It may not be seated quite properly at this point, i.e., a little bit of corrosion from the moisture and heat. It's not effecting our recording or passing the data. That's why when I couldn't bring it back up I didn't do anything beyond what I've done because I didn't want to disrupt the data from recording.

PH: You're talking about the text display?

DS: Yes. The auxiliary processor has stopped right now.

PH: What does that run?

DS: That doesn't run anything. All it runs is displays. It doesn't have anything to do with data processing or I should say data storage.

PH: Okay. It doesn't run the laptops just the text display.

DS: Yes. That's correct. The laptops are run in the same way that the tape recording is. It's just a SCSI feed and once the data is feed it's recorded and feed to the machines at about the same time. Then it's sent to the auxiliary processor to process for text display. With that one down, it doesn't affect is in any fashion with what we're doing, but it does affect what's being displayed.

PH: Will you put on your checklist whatever you have to do over there to bring my radio up because that caused a lot of confusion at the beginning of the flight and I couldn't communicate with TRMM Ops.

DS: We've already added it to the list.

PH: It caused me about a pound of sweat.

DS: We have enough sweat already without creating any of our own.

PH: Okay. I think that's the end of the summaries.

6:59 AM

PH: Just talking to Pat (of SPEC) here about the CPI. He doesn't think they've completely solved the condensation problem. They need to do some more work on it, but we did get data with the CPI. I guess he was getting some background.

8:11 AM

PH: I'm going to start the summary. The main goals of this mission were to do some coordinated runs with the Citation to the northeast of Kwajalein in lines of convective clouds. Our maximum altitude was 10,000 ft. The Citation was above us. At 19:40 in this sequence of flying, there was a TRMM satellite overpass. We did five designated lines. Each line having an A to B coordinate. I'm not going to give all of those coordinates. They will be in the flight report and they are on the recorded tracks for the Convair-580 and on the recorded tracks overlaying the TRMM radar displays as well. Basically these lines were north/south lines to the northeast of the Kwajalein Atoll. We encountered some cloud, some showers (occasionally heavy), and clear patches as well. Most of the instruments seemed to be working, although I couldn't pay a great deal of attention to them because there is a lot of radio communications. The three liquid water meters (the DMT, the JW and the FSSP) showed responses and there was quite a bit of chat in the voice recording about how they compared. They are still not showing exactly parallel responses in terms of absolute magnitude, but generally they were responding together. The Gerber PVM is still off the plane. CNC3 looked a bit better today. It's now recording, for example, about 1,000 per cc at an altitude of 3,000 ft. Temperature looked reasonable. The dewpoint looked okay. The IR thermometer was okay. The absolute humidity seems to be okay. The CPI and HVPS worked well on this flight, which is good because precipitation is going to be important on this flight for comparison with the TRMM overpass.

Okay. That's about it. Is anyone on the headset?

AR: I'm here Peter.

PH: Go ahead Art.

4:44 AM

PH: I'm going to start my summary of the flight.

This was an experimental test flight. It's been the first we've had for concentrating on aerosol measurements. We've suspected we've had leaks in the CN measurements and that's been confirmed and Ray and Don have been working on that and made some progress in isolating where the leak is. Also, for the first time, we passed bag house samples into a filter. Actually the filter needs in very clean air about 10 bags, but each bag takes about 25 min to put through the filters so that's unreasonable. In fact, on this flight so far, we've now been in the air for about 2 hr and Naoki has put only about 3 bags into a filter. Anyway, that filter will be sent back to Seattle for ionic analysis and see if they detect anything on it. Also at this altitude of 1,000 ft, Ricky exposed, in fact, just finished exposing, two of the canisters for analysis by Gammon. What we'll attempt to do shortly is to run a short height above the surf and see if we can get any giant and large particles on the PCASP and the FSSP. I think the PCASP is working. The displays that go along with the graphical display of the PCASP are now running in the 100s, 200s (1,000-ft above sea level). Art, are you on the headset?

AR: Yes I am.

PH: Why don't you summarize.

AR: Roger. This is meteorologically a strongly suppressed day as far as surface convection goes here in the area of Kwajalein. We saw no appreciable cumulus cloud of any kind from dawn right up through the flight just small shred-like cumulus fractus maybe reaching cumulus humilis sizes, cloud bases 2,000 ft. We didn't penetrate on any in this flight. During our climb to 10,500 ft or so, it was a little bit reminiscent of TARFOX because there was detectable turbidity all the way up through that level. On our original climb didn't see much in the way of haze structure. As we started to descend around, I think, 8,000 ft, we started to see some indications of layering and then picked one out around, I think, 6,200 ft seemed to be a peak and then again around I think it was 4,200 ft. But again, visually the long-range visibility quite impacted by turbidity. Clouds off in the northeast quadrant backlit looking quite yellow in this, but in terms of intensity it would probably have been 2 out of 10 say compared to normal smog situation. So it's quite clean but still noticeable. No winds today, again a little bit anomalous out of the southeast here a couple of knots at Kwajalein as the wind circulates toward the easterly wave that came through about 36-48 hr ago. I think that's about it.

PH: Thanks Art. Is anyone else on the headset?

PH: Is Chris on the headset?

4:51 AM

AR: He's coming.

CB: This is Chris.

PH: Do you have anything you want to put on the tape?

CB: No. Everything was running smoothly (on the AMMR). There's nothing really to report.

PH: Okay.

4:54 AM

AR: A little more enthusiastic surf here.

4:58 AM

NK: This is Naoki. Today I took 3 bags on 1 filter, JW1, and took two types of DMPS sample. One is 1.8 kilometers high. It has a very beautiful double-peak size distribution. The 0.3 kilometers it has very simple one-peak size distribution sample.

5:00 AM

RW: This is the aerosol station. I spent most of the flight trying to fix potential leaks in the CN counter sampling system. We've got the CNC3 working it appears, but there is still a problem with the ultrafine that I believe we know how to fix it now. Anyway, I think we're finally getting there.

PH: Okay. So the goal is to try to get there before you leave, Ray. Test it out and be happy that it's all working.

RW: Yes. I think we'll put the ultrafine actually connected directly to the inlet of CNC3 so they're definitely looking at the same air.

DS: I spent most of the flight helping Ray track down the leaks in the aerosol station and it looks like we've made some progress. We're still not 100% certain about the ultrafine, but it looks like everything else is working now.

6:51 AM

PH: I'm going to start the summaries here because it won't be long before we land. What we did here was basically fly 6 lines, coordinates given by TRMM Ops Center, with the DC-8 above us. The Citation didn't fly. Sometimes the lines changed rather quickly so it's a long story. But basically we've been flying in some cells, some precipitation, from light to moderate and occasionally heavy, and stratiform and clear. The TRMM satellite overpass was 2 min ago, but it was to the north of us. We're flying this last A to B on line 6 and then we'll be very close to Kwajalein and come into land. Is anyone on the headset that wants to do a summary now?

CB: Yes. I can speak for AMMR.

PH: Go ahead.

CB: Not much to report. The instrument appeared to be running smoothly. Some of the more interesting data came early on due to cells that we hit. Received some rather intense measurements. It will be interesting to look at later. Other than that a good mission.

PH: That's Chris on the AMMR, which is the NASA-Goddard remote sensing instrument. What does AMMR stand for?

CB: Advanced Multichannel Microwave Radiometer.

PH: So that's AMMR. It's a remote sensing microwave. It looks up from the Convair-580. Is anyone else on the headset?

GG: This is Grant. We had a few problems with the FSSP as far as the power supply is concerned, but the profiles are looking better. Hopefully we'll get them tweaked up to where it will agree with the DMT through a procedure tomorrow.

PH: Yes. We're making progress there. The profiles look good. The question is whether the drop size distribution is good and Art will look at that. Is anyone else up for a summary?

RW: This is the aerosol station.

PH: Go ahead.

RW: For the first time the two relevant CN counters worked, which is the ultrafine and the CNC3. Everything else seemed to work. There wasn't much aerosol out there so that's it.

PH: Did you look at the DMPS at all?

RW: Naoki ran a couple. It looked like it's kind of noisy (he can talk about it) because there's not much there.

PH: We got good measurements on the DMT and the JW, very good agreement. The FSSP just somewhat lower values than those but still good correlation in terms of shape of the total liquid water response. Most other things seemed to be working okay. I don't think the IR thermometer was very good today. Most other things seem okay, I think. Art, are you there?

AR: Affirmative.

PH: Okay. Summary.

AR: Well, I'd be lying if I remembered all the As to Bs, but generally.

PH: Just summarize the general conditions that we've been flying in today. Don't worry about the lines, I've recorded all that on the tape.

AR: Mostly stratiform clouds. Precipitation originating above the aircraft in almost all cases.

LS: Peter, we've got about 30 s and we'll be at the end of our track.

PH: Okay, 30 s and then we can head for home.

LS: Right.

5:42 AM

PH: We essentially achieved our goals on this flight, which was to do a coordinated flight with the DC-8 including the TRMM satellite overpass at 16:50. It wasn't a big precipitation area, basically isolated cells. We did a couple of line passes, one below cloud base and then one at 1,400 ft just above cloud base. Then we were moved to the "isolated cell" sampling mode. We were given one point and we flew cells within a 5-mile radius or so of that point. That went on for most of the flight coordinated with the DC-8 flying above and including the satellite overpass. We intercepted light to moderate precipitation. Sampled up to 18,000 ft and at various levels. We finished these studies at about 17:00 LT. Then we spent about 45 min penetrating small cumulus, mainly in their dying stages. Now we're descending to 500 ft.

5:52 AM

PH: Art, why don't you summarize now. I've done my summary.

AR: We started out by flying in that weak line of cells. I think there were three identifiable cells in there and we were really flying under the raining out, dead sort of convective area. At times visibility in those cells, however, was down to <1 nautical mile in light to maybe moderate rain. I didn't hear anything on the screen. Also I noticed a speed differential between one end of the line where I believe it was the east end had winds of maybe 10 to 15 knots. A few isolated white caps and then the west end had what looked like 15 to 25 mph winds and quite a number of white caps out there. I thought that was fairly interesting. Then after that we went to the isolated couple of cumulonimbus cells and tried to coordinate with the DC-8 and overfly there with the satellite. Also we're kind of getting our feet wet sampling cumulonimbus clouds using the new radar and we progressively entered higher liquid water regions and got to what I would consider moderate turbulence. It was probably the worst I think we'd probably consider that that we went through. Tops estimated above 30,000 on the highest top, but…(END OF TAPE, SIDE 1)…and as the top sloped back the precipitation gradually and downward the precipitation getting much heavier as you get toward the convective root of the tilted sloped cumulonimbus there. I thought that was fairly interesting that it looked so convective and so much like a deep cumulonimbus. In fact it was sawed off at about the 15,000 to 20,000 ft level. After that we tried to do a single cumulus rain shaft study and probably it was a warm rain. It was the top of an isolated chimney cumulus. It was hardly half a kilometer wide at the top. It was right around just below freezing and we followed the rain shaft down as fast as we could to capture the growth of the drops through that cloud and spun out the bottom at about 1,500 ft. Then during that time, I think we did a pretty good job of following that same shaft and documenting the growth of those drops in the high liquid water core. Drops getting progressively bigger just by the sound on the forward windscreen or the bubble, in each pass, except down maybe the last 3,000 ft.

PH: Just going near the surf here. Go ahead, Art.

AR: Sorry. I'm a little windy today. Anyway we probably didn't get the biggest drops coming out the bottom exactly because either we missed it or they had already fallen to the bottom. The other thing is the haze today. This is probably the most turbid day that I've seen here since our stay in Kwajalein. In contrast significantly, tremendously actually, with the last aerosol flight that we did about 3 days ago in which visibility was essentially unrestricted at the surface. That's it.

5:56 AM

PH: Flying at 500 ft, I just took a photograph on my digital camera just showing these little islands. Pretty typical of the Marshall Islands here. Chris, would you like to summarize?

CB: Yes, just a few words. It was good day for AMMR. The instrument appeared to be working smoothly. We were very interested in some of the work we did here and around the freezing level especially at overpass time. I think it will be interesting to look at it later, but overall a good day.

PH: Thanks. Grant, anything to say?

GG: We had some of our usual problems with the FSSP except that the outages have become more severe. We're going to replace the 5-volt power supply in it tomorrow if it's in hand and it's reached the island. The JW dropped out for a few minutes in there. We're not quite sure why that happened. Otherwise things looked okay except for the IR thermometer has gone slightly berserk on occasion. We have to take a look at that. Otherwise things seemed to work reasonably.

PH: Yes. The IR now for example is reading about 14°. It's far too low. Anyone else want to summarize?

PH: Good. Thank you, Naoki. The CPI and the HVPS (high volume precipitation sampler from SPEC) both worked well today. The PMS 2-D data was okay. It just didn't get switched onto the first half an hour or so, but subsequently it was switched on and worked okay for the rest of the flight. Except sometimes we're still not seeing the actual images on the screen, but then they'll pop up. It's presumably recording despite the fact we can't see the images.

6:00 AM

RS: This is Ricky.

PH: Summarize.

PH: Where will you do that? Can you do that on base?

RS: Yes. I asked Wendy and some DC-8 people and they can help me.

PH: Okay. Good.

NK: I should add that I detected some plume when we were in high altitude. It means that the CNC scattering coefficient and absorption coefficient have very synchronized sharp peaks.

PH: Yes. I think you mean our own pollution trail from the aircraft. Right?

NK: I think so.

PH: That finishes the summary.

4:28 AM

PH: We'll do just a brief summary here. This was a short flight, about 1 hr. It's primary purpose, only purpose really, was to do a comparison of our temperature, dewpoint and winds with the Meck tethered balloon, which we did. Then we dropped down and did comparison runs by the 10-meter high tower on Meck, but we were at about 300 ft for comparisons with gas measurements. Then, for the past few minutes, we climbed to 3,000 ft, and now we're heading back.

Art, summarize.

AR: There's not a lot to say. Down low, when we were doing our passes to the north and south, at the north end each time we were downwind of the surf, breaking on the barrier there, and at the south end, we were on the upwind portion from the surf break on each pass. If there is any aerosol contribution that got up to 300 ft we might look for it at those point. Other than that, we took off as a strongly suppressed cloud zone zipped off to the west. During the flight, in this short time, we've seen the cumulus become from cumulus humilis to towering cumulus congestus. Probably a dozen very light rain showers developed within sight in 1 1/2 hours, whereas before there wasn't even a cloud approaching the size of producing a shower. We're seeing something aloft go through here, that dry slot, move off to the west and be replaced by increasing instability here. On the surface the winds were 10 knots, hardly a white cap visible, maybe 15 knots at the most at the very beginning of the flight there were maybe a bit more white caps than at the beginning. Horizontal visibility is excellent, some haze visible, but generally greater than at least 30 nautical miles.

PH: Ricky or Naoki summarize.

4:33 AM

AR: Ricky's not on the headset. He's coming to sit down now and Naoki too.

RS: This is Ricky.

PH: Summarize.

PH: Naoki summarize.

NK: I took two bag samples onto the one filter in the marine boundary layer at very low altitude almost all day at about 0.1 kilometer. CNC3 was okay. PSAP was okay. Nephelometer was okay. In the course I found the water for the humid showed up, but Don added and it was okay.

PH: I didn't understand that last sentence. Can you repeat?

NK: In the course of the flight I found that the water to the humid, I mean the heater was short.

PH: The water to what? One of the CN counters?

NK: No, to the nephelometer.

PH: The water to the nephelometer. The nephelometer doesn't have any water.

NK: I mean the humid.

PH: Oh, for the humidification factor.

NK: Yes.

PH: It was dried out?

NK: Not completely, but it was very low level in the bottle so Don added the water.

PH: Yes. We need to watch that.

NK: Yes. I also took a can and an electromicroscope sample for each low pressure and normal pressure orifices. That's it.

1:48 AM

PH: This whole mission was concerned with isolated cumulonimbus and cumulus. A coordinate flight with the DC-8. We flew 9 lines given to us by the TRMM Ops. We didn't complete many of those lines because things kept changing and they kept moving us to new coordinates. But over the course of the last 3 hr, I think we've sampled these clouds pretty well from 20,000 ft down to about 3,000 ft. On the way back home now we will get the last few thousand feet below that. Art?

AR: This flight took place as an easterly wave was going by or post easterly wave. The clouds again turned out to be paper tigers with huge plumes of ice cloud ejecting from fairly isolated cumulonimbus and convective roots that were feeding all the ice clouds so they looked externally like something pretty nasty. They turned out not to be so tough. The liquid water core has been a small minority of the sampling today. In general the sampling went the same on the three…

AR: I was going to say that the characteristic of all three of the cumulonimbus systems that we sampled was sort of an upshear/downshear mode including the very small cumulonimbus that we flew on here for the last couple of hours that eventually dissipated. But again, it had a nice micro upshear/downshear zone compared to the 10-20 kilometer long systems that we sampled earlier so it was a nice replica. Again, what we see happening is the shear taking the ice part of the cloud.

AR: I was just going to mention the cloud tops shearing off. Not a lot of strong vertical motion…

1:54 AM

PH: Chris, are you on the headset?

CB: Right here.

PH: Summarize.

CB: I'll just briefly say that the AMMR is running smoothly. No problems to report. Some of the measurements we took up there around 20,000 ft in clear air will be useful in our calibration. No problem other than the scientist behind the instrument is still thawing.

PH: Is still what?

CB: I'm still thawing.

PH: Yes, so am I. I have no socks on. The towel that I usual use to wipe my sweat is keeping my feet warm at the moment. Naoki, summarize.

PH: Did you just run the humidification on the nephelometer a moment ago?

NK: Yes, I did.

PH: Because I see some response on the nephelometer readout here. It's sort of gone up sharply several times.

NK: Yes. There was a very, I mean puddle-like response, but there was no synchronized increase in the scattering coefficient.

PH: We can talk about that on the ground and take a look at it.

NK: Yes.

PH: Ricky.

PH: Good. Grant, do you have anything?

GG: Data system performed basically normally although the IR temperature is going berserk at the moment. It has been a little bit anomalous during the flight. The FSSP decided to grace us with its presence for most of the flight even though the power supply is known to be intermittent. Otherwise the FSSP, JW and the DMT agree at least in features and sometimes in magnitude frequently during the flight.

PH: Did Don have anything for the tape?

DS: Yes, I do have one quick comment. The pressure gauge on the bag house for some reason has not worked properly when the plane is pressurized. It works fine when it's unpressurized. So that will answer Naoki's question about whether the bag house itself is working or not.

PH: Okay. We still haven't solved the leak problem on the aerosol. We've got to look at that again otherwise we're going to have to do our aerosol measurements unpressurized.

10:37 PM

PH: We were well coordinated with the DC-8 and the Citation above us on prescribed line 1, which is the only line we worked today. We did a run south of Kwajalein below cloud base. Not on line 1, but prior to getting on line 1. Then we climbed to 3,000 ft and headed out to our Point A on line 1. Then we did our first run A to B at 8,000 ft. It was about a 35-mile run. Then B to A at 11,000 ft. Then A back to B at 14,000 ft, which was +1°C. But before we reached B, the pilot decided that we had to return to base. Chris, will you do a summary?

CB: Not much to say, a short mission. The instrument appeared to be running smoothly. Beyond that, no report.

PH: We broke away from our run from A to B at about just over the half way point and now we're heading straight back to Kwajalein. Art, do a summary.

AR: Roger. The weather situation today we seem to be in the backside of tropical and possibly formation of a formative stage of a tropical depression, very disturbed. Light winds all the way to the top of the troposphere and nearly quasi-stationary large areas of convection. A very slight drift toward the south offshore of Kwajalein during takeoff. Cloud base today 1,400 ft. Our lines A and B marked by generally very much like a CYCLES flight. It was kind of embedded in clouds <5% of the track impacted by convection and in fact the only real convection we saw is at the turnaround point, I believe it was B, in which we saw extensive prolonged regions of 1-2 g in the DMT. Sadly at that point it was evident that the FSSP was really on its ear. Almost no liquid water in the FSSP and also the JW was very poorly reflecting those high liquid water bumpy regions that we experienced. Back to the drawing board on those. I guess that's it. Generally quasi-stratiform rain, pretty steady it seemed like the whole lines 1 and 2 of A and B.

10:41 PM

PH: We're doing a spiral descent here, pretty rapid. Is anyone else ready to do a summary, Naoki or Ricky?

PH: Okay. Naoki. We have been in cloud and rain most of the time so not much for aerosol.

PH: Thank you. The CPI and the HVPS (high volume precipitation sampler) worked fine on this trip.

(k) Summary of UW Flight 1793 (August 23, 1999)

5:54 AM

PH: I'm going to start my summary of this flight. It started off with a coordinated flight with the DC-8 and the Citation. We were given a number of lines to fly by TRMM Ops. Actually, in terms of numbered prescribed lines, it was seven of which number two was never done and there was frequent updates of the lines A to B. I assume these were coordinated with the DC-8 and the Citation above us. Our ceiling was 18,000 ft. Anyway we flew backward and forward on those various lines basically in weak stratiform situations. We hit hardly any convection. Weak stratiform light snow falling out of multilayers above us. Then after line 4, we did a spiral from 18,000 ft down to cloud base. Actually it was from 18,000 ft down to 12,000 ft descending at 250 ft/min. These spirals being the ones needed by Tom Wilheit. Then we did line 5 and then line 6 and line 7. Then we did another spiral, which was a more complete spiral from 18,000 ft down to 2,000 ft. Actually it might have started even higher than that. It might have started near 20,000 ft. Anyway we went down to 2,000 ft by which time we had run out of precipitation. Now we're doing another spiral nearby in a very similar rain shaft, but we're spiraling up this time starting at 10,000 ft going up essentially as fast as we can, which means 1,000 ft/min to begin with and slowing down as we go up. Is Art on the headset?

AR: Yes, I'm here.

PH: Okay. Summary.

AR: Yes. I think you covered all the bases that I would have, multilayered. It was very much like a STORM-FEST flight in many ways. Uniform conditions from one end of the leg to the next. Almost no liquid water sampled with exception of two weak turrets. I believe it was on the way to line 1 or line 1. I don't remember now. We got 0.5 g. The FSSP spectrum looked pretty decent during that. At one point just to emphasize the multilayer aspect, I was able to count 5 layers of altocumulus clouds attached to the second weak stratiform system that we pummeled. Other than that it was a windy day anywhere from 15-25 knots of wind on the surface at the time I could see the surface judging by the white caps. It was a deeply moist atmosphere where these systems were able to grow and send out shelf clouds and anvils that were long-lived because of the deep moist conditions of the atmosphere. The other thing that probably stood out the most to me was the depression of the melting level today. It was kind of indicative of the overall easterly wave upward motion scenario that we had that leading to slightly steeper lapse rate than we've seen, which makes a huge difference when you have ocean temperature around 29°C.

PH: In terms of instruments, it was disappointing today because the DMT and the JW did not work. Never really tested the FSSP. We may yet do that if we get a chance before we land in some higher liquid water, but the FSSP was at least active. Also the IR temperature sensor was not working. The Ophir was not working. The HVPS and the CPI were not working, and we didn't have a SPEC operator onboard to see the reason why. So quite a lot of important instruments were not working. The good thing is that the PMS 2-D cloud and precip probes were both working nicely, and maybe the FSSP, so that gave us the essential data we needed. Any other instruments not working, Art?

AR: Not that I know. I think you covered it pretty well. The one thing I think that might have had a negative impact was after we took the tape off and everything and we were taxiing. We had these extremely large drops begin to fall and then the rain picked up and I think we might have lost maybe the CPI or maybe even other instruments during that heavy rain during the taxi period and takeoff.

6:07 AM

PH: Jim.

JW: Yes.

PH: Just give another quick summary for the tape recording of your impressions of the flight.

JW: Yes. The airplane is very nice. I really like this spiral maneuver, very tight. We did get a very good data set from this weak rain. We can do it again next time.

PH: Yes. We hope to do it under a variety of conditions. Naoki, are you on the headset?

NK: Yes. I'm on it.

PH: I know it was nothing for you really because this was aimed at clouds and precipitation. Hopefully we'll get plenty of opportunities to get good aerosol measurements, but do you have anything you want to put on the tape in terms of what you saw on your instruments?

NK: Yes. For me all the instruments worked pretty well especially the CNC recorded the lowest concentration of about 70/cc in high altitude. Also I took two samples from the bag house. One was at the 2.5 kilometers during the ascent after the takeoff. The other one is at 5.9 kilometer, very low altitude, for the quartz filter.

PH: That's the quartz for the carbonaceous measurements.

NK: Yes. Just for the test of the flow rate. I'm not sure if its detectable. The bag house worked very well in view of the pressure gauge. That's because in the last two flights the pressure gauge didn't work so I was very suspicious that I could take a sample, but today the pressure gauge functioned well so I was very confident that I could take an ambient air to the bag house.

PH: Did you do any measurements on the humidification factor?

NK: No, I didn't do it because the scattering coefficient was very low, but I took two DMPS samples. The sample taken at the 2.5 kilometers was very nice, beautiful size distribution.

PH: Okay. Good. So you got something out of this flight. We'll do some dedicated flights in the boundary layer before long.

NK: Yes, I hope so.

6:22 AM

PH: We should give kudos here on the tape to Bob Eatwell for a fantastic job in troubleshooting what appeared to be three independent problems with the right engine over the last week or so. He seems to have found out the problems and solved them. Also Don helped with that and Grant as well. Everyone sort of pitched in with these problems.

AR: Hip hip hooray.

5:55 AM

PH: I'm going to give a brief summary of today's flight. It was disappointing from a couple of points of view. First of all we didn't find much precipitation out here today. There was a lot of scattered cumulus, some dying cumulonimbus, very sort of suppressed situation, but all three aircraft were up in the hope that we would get something developing in that time of satellite overpass time (which was 05:40 Greenwich). Initially we went off by ourselves to work small cumulus. We did a fairly good study of quite a few warm, small cumulus, no precipitation, with sampling at various altitudes. Then we did some measurements that were interspersed with aerosol measurements below cloud base, primarily to get humidification factors. I think we finally got some reasonable measurements there, remembering that we had to fly at constant altitude during the period that the humidity is ramped up, which takes 10 to 15 min. Once we did that, we started to get some decent humidigraphs. We dropped down to 500 ft and got another good humidigraph that appeared to show the deliquescence of salt particles, but we'll check that in post analysis.

We were then directed by the TRMM Ops Center to an isolated target quite a distance away, about a half an hour or so, so it was quite a trip for us to our first Point A. By the time we got there, the clouds had dissipated, and we were directed to a new Point A. This Point A was a dissipating cumulonimbus, which we worked during the time of the TRMM overpass. We flew between 18,000 and 15,000 ft, which was near the base of the virga. The other two aircraft were above us. Maybe the tops were at 26,000 ft so the Citation probably got something, but no one was very impressed with the clouds. After the satellite overpass we continued to work the decaying virga.

Instruments were a problem today. Perhaps it's a good thing it wasn't a better case study, otherwise I would be more upset about that. Apparently the problem was we didn't have the HVPS SPEC instrument onboard, since SPEC hadn't fixed it, and the SPEC CPI wasn't working. Peter Trost (SPEC operator onboard) thinks it's a circuit breaker box. To top it all, our PMS 2-D cloud probe packed up. I don't think it worked at all on this flight. Probably a laser has died. We're not quite sure if the PMS 2-D precipitation probe is working exactly right, but I think we were getting some images on it, but it didn't seem to show much activity maybe due to lack of particles. Anyway there is some data on there. Ophir is not working. Wrong date on the video display, which means wrong date on the data stream. Today showing 010896 instead of the correct date, which is 240899. We don't know the reason for that. Also the GPS roll angle on the text display, which comes, I assume, from the Tansvector, seems to have a constant offset of about +3° or so when the pilot's roll angle is indicating essentially zero. I just should mention that we did do a calibration for the NASA Goddard instrument onboard by flying at 18,000 ft and rolling 30° to the right and then 30° to the left, which gave them a calibration with a fairly clear sky above and maybe some thin cirrus here and there.

PH: Naoki, why don't you do your summary.

NK: Yes. I should have mentioned that this morning Don and I exchanged the bag so as far as the bag's concerned I'm very confident of the bag's status, but somehow the bag system driven by pressurized air was not functioning. Don helped me to manipulate with bag power and I could take two good humidifications at 1,000 ft and 500 ft and one Teflon filter sample, which is JW7 at 500 ft. But I didn't have much time to take the quartz filter sample. The CNC3 was working well. Also, the nephelometer was working well. But the ultrafine CNC was not, because of a shortage of butanol; but now it is working because Don supplied additional butanol.

PH: We need to watch that butanol and make sure it's topped up. Did you note the times when it was working properly and not working properly?

NK: Yes. I can recover that from my notes.

PH: Did you note those times on the tape recording?

NK: No, I didn't record it, but I have a number of them on my notes.

PH: After we've finished the summaries, you should put that on the tape recorder because your notes may get lost.

NK: Okay.

PH: You took a filter sample for carbon, but you didn't do one for ionic species and you didn't do anything for carbonaceous species, is that correct?

NK: I took just one Teflon filter sample for the ionic species but not for the carbonaceous or Teflon filter.

PH: Okay. Just one for ionic. If we go down now to the boundary layer are you going to do one for carbonaceous?

NK: No. I want to add one more bag to the same filter on the Teflon to be able to analyze it.

PH: You want to do another Teflon?

NK: Yes.

PH: So that would be two Teflons today.

NK: No. One Teflon but two bags.

PH: Okay. Art, why don't you do your summary?

AR: Yes. Yours was pretty encyclopedic. I wasn't going to add too much except for today's meteorology.

PH: That's what you always say and then manage to speak for half an hour.

PH: Okay. Good. Jim, are you there?

JW: Yes.

PH: Say a few words.

JW: We did have a very nice calibration run and this is a very important procedure for our instrument. We hope we can do it maybe once every flight, but whenever we have a chance we like to have one like that if possible. We can make use of today's data set as well. We can take this data to check for our instrument calibration as well. So it's a good data set we can make very good use of it. I would like to thank Peter and the pilot for making this possible. Thanks.

PH: Okay, Jim. We'll do that whenever we can. It doesn't take much time, so we'll just work it into most flights.

JW: Okay. Thank you.

PH: Anyone else what to say anything by way of summary? No. Maybe Don. Where's Don? Can someone get Don on the tape?

DS: I'm here.

PH: Anything to say?

DS: I haven't got much to say, but the JW is not working, the two 2-D probes appear not to be working very well at the moment, and the bag house accumulator didn't accumulate so we operated the valves manually.

GG: And we also ought to note that the Ophir is dead, but the IR thermometer is starting to do something a little bit more reasonable.

PH: The IR looked okay when we were flying low down and that may be all we can expect of it. There's quite a list again, Don and Grant, to look at. All we can do is to keep plugging away at the problems.

DS: At least we have two liquid waters this time and they compare fairly well.

PH: Yes, that was a plus and we're back flying, that's a big plus.

6:15 AM

PH: Just to summarize, we've been working lines. There were four convective cloud lines prescribed by TRMM Ops and we worked them all at various altitudes. One of the lines was fairly vigorous and caused a lightning strike, which took out our radar. The big disappointment was not having the two SPEC instruments working. The CPI is on the ground being worked on, and the HVPS didn't work. Also our PMS 2-D precipitation probe was out, although the PMS 2-D cloud probe was up. All three liquid water instruments worked reasonably well. Our flight tracks were coordinated with the Citation and the DC-8 above.

Don, do you want to say anything while Art's coming up?

DS: On the bright side we got the JW working. The FSSP looked pretty good again. The King worked. On the downside, our radar went down. Hopefully, that's not too serious. The 2-D cloud probe worked fairly well. The 2-D P did not work at all. I'm in a little quandary as to why that's not working, but I'll keep working on it.

PH: Don, I've asked the TRMM Ops to contact Grant to tell him the radar has gone out so he can meet us on the ground and start working on it. Also, the SPEC people should meet us on the ground and get working on their two instruments.

PH: Okay, Art, summary.

AR: This is a day where we saw enhanced convection. An easterly wave was approaching on a high-pressure ridge that was exiting the area, and that is kind of what we saw to the east of Kwajalein today enhanced convection breakout about mid-afternoon. The cumulus tops getting up into the cirrus levels and shearing off drastically toward the east as the systems moved toward the west. Today was one of the windiest days we've seen. The surface winds were probably in the order of 15 to 25 knots, pretty steadily all day, numerous white caps, and some of the lower visibilities we've seen in the boundary layer here in our stay at Kwajalein. Droplet concentrations again looked to be in the 100 to 200 range in the cumulus turrets. I thought the first line of cumulus clouds we hit (there were about 5 or 6 of them in a row) were outstanding examples of the kind of turrets that lead to the cumulonimbus complexes that we sampled just after that. I think it was line number one. This was kind of a precursor line, I think, in our eastbound heading that we hit, but those were just real great examples of those building blocks. After that we penetrated the line and I think Peter has probably covered that already. I wasn't on the headset. It was a mix of stratiform convective bubbles and bursts of graupel. It was the usual thing we see in building and precipitating cumulus clouds in the young stages. That's about it, I think. There were good examples in those first few lines that we carried out.

AR: Just a final note. I'm going to look at today for spheric activity, because I'm guessing those are aircraft induced lightning strikes. You know it's just too bizarre to have two aircraft struck.

PH: Yes, I think that's correct. I don't think we were struck actually. If we were, it was an induced strike. That could be much less damaging than an actual strike.

AR: Yes, I would agree.

PH: Jim, summarize.

JW: Our instrument is working just fine. When we passed through the rain cell, it responded to the rain signature well. How useful the data set is I really cannot tell right now. We need to check against other instruments like yours, for example, Peter. That's all I have to say.

PH: Okay. The DC-8 was getting good remote sensing signals on the AMMR and the other instruments, the precipitation radar. The Citation was above us getting good measurements as well. So these were fairly well coordinated lines that we were doing today.

JW: I think it's a good data set to work with.

PH: Naoki, summary.

NK: Yes. I don't have much to say from the aerosol station. I didn't take any bag samples. The instruments were working well except for the ultrafine CNC in the former half of the flight, but in the later half of the flight it recovered because Don added butanol. I once saw a synchronized increase in the scattering coefficient from the nephelometer and the PSAP in the clouds. I think it is similar to what was recorded in the last FIRE-ACE 3 in Alaska.

NK: Yes. It's pretty high.

6:25 AM

DS: I also wanted to mention that the IR temperature seemed to work fairly well today. I have a couple of hypotheses about what is going on there. One of them is when we climb real quickly there is an internal heat sink source that it uses and until that equilibrates it's not going to read correctly. The other thing is when we came down very quickly we may have moisture inside from condensation, once the instrument gets cold soaked, that probably affects the way it functions. This morning, when it had a chance to dry out, everything looked great again. It's been working most of this flight as well.

PH: It wasn't working at the beginning. It was reading negative temperatures, but it's working okay now. I hadn't really watched it throughout the flight.

DS: I was watching it. At the very beginning it reads negative as it charges up and stabilizes. When we went off the runway, I saw the high temperature drop or the ground drop down to the water temperature and it looked pretty good most of this flight.

7:01 AM

PH: I'm going to give a summary now of this flight. Basically we were concerned with sampling one fairly nice band of clouds with some precipitation in it. It had some good cells in it. We sampled it at various levels from about 18,000 ft, 15,000 ft, 16,000 ft and so on. Including, at the end, a spiral right down to 1,500 ft through portions of the rainband. At the same time the Citation and DC-8 were above us, the DC-8 doing a "bow-tie" and the Citation picking up what clouds it could above us. In a couple of cases we got the Citation and ourselves in the same updraft, which might be interesting. There was a satellite overpass at 16:52 local time (classified as number 1 so important for TRMM), which might have caught some precipitation in the rainband we flying in, although there was not a lot of precipitation around. We did get that band in various stages of growing and decaying cells. In the latter part of the study, starting at about 17:50 local time, we did an aerosol study. This consisted first of a bag at 1,000 ft for humidification factor measurements and then a bag for filter samples. I think they were ionic filters, but Naoki can clarify that. Then we climbed up to 10,000 ft circling around the cloud trying to get detrained air for electron microscope studies that Ishizaka will do for do for us; that was a 10 min sample near cloud top of detrained air. Then we descended also sampling detrained air. We just finished that descent, so that should be a good sample of air basically detrained from clouds for particle studies. We're now heading back.

In terms of instrumentation today we had no CPI or SPEC HVPS aboard; those two instruments were being worked on by SPEC. The three liquid water measurements onboard were working okay at the beginning, but the JW dropped out fairly early on in the flight. The FSSP looks okay and the King. The PMS 2-D cloud and 2-D precipitation probes worked okay as well, which was a bonus on this flight since we had no SPEC instruments. IR thermometer I didn't look at it much, but I don't think it was too reliable when I did look at it. That's about it. Okay, Art, summarize.

AR: The weather today was post-easterly wave. We had lightning visible at dawn as the easterly wave moved off to the west. It was followed by very suppressed conditions that lead to kind of a disappointing TRMM overpass. Nevertheless, I think we picked a pretty good line of cumulus congestus that had about 4 or 5 or 6 cells in it. All of them had some precipitation, and at about the time of the satellite overpass one of them sprouted the highest top in at least 30 nautical miles so we got a pretty lucky break on that one. The main thing I would add to Peter's summary is that we had two visuals on the Citation from the bubble back here and because we had that visual we were able to go back and underneath. First we saw that we had been in the same turret that the Citation was in and about 2,000 ft lower. Then when we had another visual we were able to go back through that same area the Citation had been at and about 2,000 ft lower to document exactly the microstructure of that single little element of the turret. I would mention that they were like little stalagmites that kind of stuck out from the main body of the cloud. They were really amazing little features. Cloud bases today about 1,400 ft at the beginning of the flight about 26° to 25°C. We're just now were hitting cloud bases at 1,000 ft so they are a little lower and a record +27°C. Of course, with these clouds, warm rain developes when they get to 5,000 ft in height above the surface and lots of rain by the time they get to 10,000 ft and 15,000 ft.

PH: Thanks Art. Naoki, summarize.

NK: Yes. For the instruments in the first part of the flight the ultrafine CNC was over ranged but Don helped me add the butanol and then it recovered in the middle of the flight. The other instrument worked well especially CNC3 was very low during the flight. Now it's 132. I took one bag sample for the humidification and it was okay, but I think the second sample was a failure because the bag was damaged. I took probably 4 or 5 electron microscope samples for Dr. Ishizaka.

7:11 AM

PH: Grant, do you have anything to say?

GG: You summarized the instrument operation pretty well. I think the FSSP-100 is due for another tender loving care operation. We need to clean and realign it. The other thing is that the new radar head that we put out on the wing this morning seems to be working quite well.

PH: Is Don on the headset?

7:15 AM

DS: Well, the only thing I have to say for the tape is the PMS 2-D precip probe worked, but it didn't function as well as I was hoping it was going to.

PH: We'll have to see when we look at the data whether we're getting the images. I mean, we did see some images there, but there are lots of extraneous lines around. Also it was triggering the records when it shouldn't.

DS: Yes. That's quite true. The JW dropped out again. I'll have to look at that a little bit further. I think that tomorrow we're going to focus our attention on the HVPS and the 2-D probe.

PH: That's the end of the summary. We're probably about 15 min out from landing. I'm going to come off the headset.

11:29 PM

PH: A quick summary. This was a short 2-hr flight, but very useful. We were the only aircraft up. We worked two lines just off the northwesterly tip of the Kwajalein Atoll. The first line number 1 we didn't work for very long. We were going from Point A to Point B and then Point B to Point A. Point A to Point B at 17,000 ft. Point B back to Point A at 17,000 ft. Then we were given a nearby new east-west line number 2 by TRMM Ops Center. We've been working that for the last hour or so. We've gone along that line and around that line at about 15,000 ft, 17,000 ft, 18,000 ft, and 13,000 ft. It was a fairly vigorous line, quite convective, some lightning, dbz up in the 35 range. So it looks like a fairly good little data set on a convective line, which was dying towards the end as we did the run at 13,000 ft. We're now heading back. Okay, Jim, did you see anything today?

JW2: Yes, we did. Our instrument is working just fine. When we went through a few rain cells, it responded well.

PH: Good. The HVPS was up and working again quite nicely today. The PMS 2-D cloud probe is working. The 2-D precipitation probe is uncertain as to whether or not it's working, since we haven't been seeing many images in real time from it. The CPI not aboard. SPEC is still working on that. Art, would you like to summarize?

AR: Yes, I'll try to do this. We flew off today toward a convergence line that had been persistent since dawn anyway to the northwest through north through northeast of Kwajalein associated with an attempt with the ITCZ to form in that region. We sampled some fully developed cumulonimbus clouds there. We probably got one of the best data sets of any of our flights, I think personally. I think Ken and Larry bit the bullet and went through some stuff that probably other people might not have gone through. So as a result I'm very happy with this.

PH: Okay, good Art.

5:41 AM

PH: I'm going to summarize the first part of this flight, which was a cloud precipitation study. We looked at two lines. Actually, the first one was an area more than a line. I called it area 1. We started off at 18,000 ft. Then we went from our Point A, which is on the tape, east from that. It was stratiform cumulonimbus top. We spiraled from 18,000 ft to 1,000 ft in that point. It was really a complex decaying system. In many areas it was glaciated ice debris, and we got right down into the rain beneath as well.

The second cloud band, let's call it a line, was associated with the TRMM overpass at 16:04 local time. We had the Citation and the DC-8 above us. We worked that line pretty thoroughly for quite a while, starting at about 16:40 local time up until about 17:35 local time. We penetrated it at various altitudes from 19,000 ft down to 1,000 ft. There was some developing cells within that, which produced fairly strong updrafts and quite a bit of precipitation.

7:17 AM

PH: Now I'm going to summarize the second mission that we did today. This was a pretty comprehensive set of measurements of aerosols, quartz and Teflon filters, Gammon cans, and humidigraphs. Starting from 1,000 ft we did our humidigraph sample in what now appears to be fairly polluted air. Then, before leaving that altitude, we grabbed a bag for quartz and Teflon filters. We climbed to 7,400 ft circling around clouds for detrained air for electron micrograph aerosol samples. Then, on the descent, we grabbed two more Gammon cans at 6,300 ft and at 7,400 ft. I might not have mentioned that we grabbed two Gammon cans at 1,000 ft also during the period that we were doing the humidigraph. When we got down to 1,000 ft again we grabbed a second bag for filters plus another Gammon can. We climbed again, between about 06:45 and 07:02 Greenwich, to 6,000 ft in detrained cloudy air. We grabbed a Gammon can at 06:53 at 3,000 ft. We then descended in clear air, grabbed two Gammon cans at 5,000 ft and 2,000 ft. We ended up by taking a final filter sample for quartz and Teflon filters at 1,000 ft at 07:16 Greenwich. We're now heading back to Kwajalein at 2,000 ft in the polluted layer where we'll continue to run the electron microscope slides.

PH: Naoki, summarize for the tape.

NK: For the aerosol measurement, today's sampling is very satisfactory for me. This maybe the first complete data set for the carbonaceous and ionic filter samples and also Dr. Ishizaka's electron microscope samples. I'm very happy to have this good data. I'm very interested to analyze this data and have an interesting result.

PH: Good. We hope to repeat it several more times before the end of the program.

NK: Yes, I appreciate it.

7:39 AM

NK: Today's bag samples were all successful.

PH: Good news.

4:57 AM

PH: I'm going to start my summary.

RW2: Peter, before you do that, I'm going to be off the headset for just a second while I check my flow meter for the nitrogen.

PH: Okay. This was one of our best flights. In fact, it was meant to be a "no fly" day, but we got up and flew anyway because there was quite a lot of cells and precipitation around. We did, in fact, get into some of our best rainband studies to date. We flew 4 rainbands, although number 3 rainband (that was officially numbered 3) was abandoned. Some of these rainbands were quite convective. We got into some of our strongest updrafts on some of them, strong echoes around. But others, particularly the last one (which was line 4), started off convective but then turned into stratiform rain. Also, we've sampled higher than we've sampled previously. We got up to over 20,000 ft.

RW2: Okay, Peter, I'm back on the headset.

PH: We got to over 20,000 ft on one of the runs. We got good crystal images. The CPI worked nicely. The HVPS worked nicely. The only things that packed up was the PMS 2-D cloud probe right near the end of the flight. The PMS 2-D precip probe on the other hand came up at some point in the flight and is probably giving intermittent images. In either case both of these probes are backed up by the HVPS and the CPI. The FSSP seemed to work okay. The King worked okay. So basically we got a good set of measurements.

5:04 AM

PH: Art, do you want to summarize?

AR: I tell you working the CPI left me at a loss for some of the early details of the flight. The first group of clouds that we worked I can mention were tops in the 35 to 45,000 ft range. In other words, it was some of the strongest convection we've seen. The middle group had tops more in the 30 to 35,000 ft rather weak. That was the satellite overpass. The last group again had tops well into the 35 to 45,000 ft range. Today's meteorological background was a short wave from the middle latitudes working its way southward toward Kwajalein. At the same time an easterly wave approached Kwajalein from the southeast and apparently those two resulted in the ignition of this extremely active convective day. I'd say this was equal to, in the number of systems and the aerial extent of the most active day, what we've seen here, with perhaps the exception of the 3.3 inch rain day that we flew on back about 2 1/2 to 3 weeks ago. Other than that, I'd say the best part of the flight was the cumulus turret with the pileus that we penetrated at 20,000 ft. That was an excellent data point at that level about –5° to –7°C. We had not previously penetrated a turret of that strength at that level so that was a great data point there. I don't think Ken liked it too much, but it didn't have an echo. It did have a lot of turbulence. Most of the penetrations that we did, I'd say probably 95% or more, were absent of any appreciable liquid water. So that means that they're in the decaying stage, particularly the cumulonimbus cluster at satellite overpass. One final thought, visibility today was improved, a moderately hazy day. Winds were in the 10 to 15 knot range, and looking down now on the white cap activity I'd say it's more in the 15 to 20 knot range out there below the aircraft right now. That's it.

PH: Thanks Art. Richard.

RW2: We got into several periods of stratiform rain. What we'd like to see is maybe to do some spirals in that stratiform rain and stay in there a little bit longer. It was good that we got a couple of periods of good stratiform rain. Thanks.

PH: Okay. Also, we did a calibration left and right bank for the AMMR.

5:08 AM

PH: I think I should add that unfortunately our transponder on the aircraft went down today so our tracks will not be on the TRMM radar display, which is a pity because they would look very nice superimposed upon the several rainbands that we sampled. Of course, we do have our position for post analysis from our measurements onboard, but they were missed by the TRMM radar. Naoki and Ricky, not much of a flight for you, but do you have anything to say?

NK: The aerosol instruments were working well except for the ultrafine CNC. Today especially the PCASP showed a strange increase several times. I think it's probably due to the artifact of the cloud particles.

PH: Yes. Well the very small cloud particles might be detected by the PCASP. Speak up Ricky, you're very faint. Put it against your lips. That's the way it should be.

5:10 AM

PH: Okay. I thought this was going to be an aerosol flight, but it turned out to be one of our best TRMM flights. Don doesn't have anything for the tape. Does Grant? This is Grant's last day today. He heads for Italy. I'm sure he's very sad to leave us all.

5:11 AM

GG: We were able to extract horizontal winds from the data files being put to tape and put the horizontal wind display up on the laptop computers. Don put together a little package that extracts the data and puts it in there labeled external. It's fairly easy to read.

Flight aborted due to problem with right engine propeller. No significant data collected and no summary given.