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It was a pleasant surprise that we had an opportunity to fly these

aircraft in convective systems, because it had been a strongly

suppressed day through late afternoon. However, the scattered echoes

in the northern semicircle strengthened substantially during the hour

before the go-no go decision had to be made at 0600. The Convair still

had no weather radar, so we elected to lower the no-fly zone such that

the Convair stayed at/below 10Kft and the Citation above 12Kft.

The best targets at takeoff time were a series of small mesoscale

radar echo groups, each about 15 X 30 to 15 X 50 km in extent, almost

forming a continuous band oriented SSW-NNE to the NNE of Kwaj.

Immediately after takeoff we set line 1 in the southernmost of these

just east of Meck. The aircraft flew this line but we did not have

time to get them well-coordinated in time before this feature weakened.

So we quickly set line 2 to cover the larger system at moderate range

to the NNE, and passed those coordinates to both a/c about 0658. This

zone also weakened, so at 0725 we passed coordinates for line 3 to both

aircraft, to cover overpass time in a stronger group of echoes

northeast of Roi Namur.

The aircraft spent the period ~0730-0812 making 4 passes through this

group of cells, some of which remained fairly strong throughout the

period. The system had some 17 dBZ echoes to 12 km, 22 dBZ to 10 km,

and 27 dBZ to 6 km. There were minor changes in the coordinates so

lines 4 and 5 were close to line 3. Due to an error by EJZ, the

originally transmitted line 3 coords brought the aircraft within 2 nm

rather than the intended 5 nm of the Roi Namur no-fly zone. As a

result, some deviations from the intended path were flown by the

Citation, but they stayed within the intended system almost all of the

time.

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Kwajex Citation Flight Summary

Date, Flight Number: 1 August, 99/ 1

Period of Flight (approximate): 0635 to 0840 GMT

Flight Scientist:Stith

Crew: Miller, Streibel, Stewart, Weaver

Flight Hours: 2.1, 4.3 cumulative (out of 100)

Weather Obs: Sc t cu north east

Photos Taken: VHS

Purpose of Flight: TRMM overflight, coordinated mission with Convair

Malfunctions and data Quality observations:INS pitch inoperative—no vertical winds, First digit on INS latitude in error. SPEC probes working well today—no condensation either. No Dew Point today--bad wire

Observations and Flight Descriptions: Conducted several passes through convective and stratiform elements according to directions from operations. Rather complete set of measurements about five degrees warmer and colder than the freezing level and at freezing level. Saw large aggregates (cm sizes), rimed particles, and raindrops. Should be good case with two aircraft coordinated sampling (Convair below 10,000). Deviated from track to avoid Roi, but remained mostly in cloud.

Flight Notes:

0638 Off, checking things out

0645 Setting up initial point

0645 No Dewpoint?

0645 No Pitch, Roll OK, Heading OK

065208 Crossing point A in small drops—drizzle

065740 End of line in mm drops

0702 Into rain region

0706 Some large drops and melting aggregates at +5 C

0711 Step up 4000 feet here to get near freezing level

0714 Circle to link up with Convair at –1 C

0720 Checked dewpoint—no joy

0725 starting down the line in mix of aggregates and rimed particles

0737 Discussion with pilots about position

0744 Deviate east to avoid Roi

0749 Starting another line—large aggregates here

0751 up to 20000 feet, another line

0800 light chop

0802 in cell

0803 Check data here for data gap of about 1 min in particle data only

0813 End of TRMM work, will try and find a clear spot for field mill maneuvers

0822 Start maneuvers

0822 roll left 45 degrees

082236 roll right 45 degrees

082330 pitch 10 up

082335 pitch 10 down

0832 Hit small cu 90/cm on FSSP, 0.8 g/m3 lwc, 30 micron drops

0835 RTB

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UNIVERSITY OF WASHINGTON FLIGHT FOR KWAJEX

DATE: 1 August

UW FLIGHT : 1786

Goals of Flight:

1) Coordinated flight with Citation in precip line NE of Kwaj

2) Coordinated flight with Citation beneath TRMM satellite overpass at 1940 LT

Convair to fly below 10, 000 ft . Citation above 12, 000 ft

Accomplishments:

Goals # 1 and 2 achieved. Nice mixture of stratiform and convective precip.

KWAJEX flight hours remaining: 77.67