Class 2 Overpass @ 1640

DC8 off at 0300Z Convair off at 0306

Early in mission worked a short line 8 12N 167 53E to 8 10N

168 20E (Near Namu). As it began to die down we shifted to a pair

of cells near Roi Namur; initial coordinate 9 6N 167 49E and called the

called small cell mode.

General Impressions:

There wasn't much rain there and we probably wouldn't have flown

without the overpass. The coordination worked well and the few

systems that we had to work lasted long enough to let us get some data.

We had our first test of the small cell mode and it worked pretty well.

The Convair switched cells a few times but we were able to follow it in

the ops center and shift the DC8 accordingly. We were finally able to

get the Convair into storms at the levels we wanted and the data will

be useful for looking at convective regions. We didn't see much

stratiform.

2-aircraft mission for Convair and DC-8.

DC-8 t/o ~0300, land ~0530 (not exact)

Convair t/o ~0305, land ~0625 (not exact).

TRMM Overpass at 0450, a/c tracks may be just within NW edge of PR

swath.

The decision to fly this mission was strongly influenced by the

excellent TRMM overpass at 0450. At decision time the scattered radar

echoes were slowly decreasing in coverage, but we were able to get the

aircraft well-coordinated on two systems. The first was near Namu

Atoll to the SE, on a 35 km line of echoes which weakened. This was

flown for only two flight lines, from about 0320-0342.

At that time, we directed the aircraft to a smaller but more intense

group of cells centered at 09 06 N 167 49 E. We had anticipated the

best way to fly such a small target, and declared "small target mode".

This storm was worked in close coordination by both aircraft between

0350-0510. After 0510, the DC-8 returned to base, and the Convair

elected to do some non-TRMM work for about an hour.

The small target mode worked quite well, with the center point of

interest picked mostly from the radar at the ops center, but using the

Convair's penetrations and observations as a guide. The DC-8 executed

short-legged bowtie pattern centered on the same point at 35Kft. The

center point was shifted westward at about 15 knots during the

coordinated observation period. At intervals about 9-10 minutes apart,

the DC-8 passed over the center point within 1-4 minutes (estimated) of

the Convair. Both aircraft noted moderate to heacy precipitation. The

Convair stepped up to 18Kft, then did the passes at overpass time at

15Kft, or near the freezing level.

The only instance of slight separation occurred around overpass time,

when the Convair recommended shifting the target about 5 nm north from

the 9 05 N latitude which had been the track of the center. There was

apparently some new growth at that location. The DC-8 was then

directed to pass over that point, then both aircraft did one last pass

back near 9 05 N before deciding to end the pattern.

_______________________________________________________________________

A coordinated mission was flown with the University of Washington

Convair. A TRMM overpass also occurred during the flight. The DC-8 was

in the air at 0300 UTC. The DC-8 began by climbing to 35,000 feet to

set up on a line between 8 degrees, 12 minutes North latitude, 167

degrees, 53 minutes East longitude and 8 degrees, 10 minutes, 168

degrees, 20 minutes East longitude.

Next, the DC-8 was directed to perform a bowtie pattern in the

general vicinity of 9 degrees, 7 minutes North latitude and 167 degrees,

48 minutes East longitude. This single convective cell was sampled.

During the multiple passes of the DC-8, the storm was observed by AMPR

and cockpit observations to grow, shear, and then dissipate. This case

should provide yield a good time history study.

All the DC-8 instruments performed well during the flight. A total

of 2.5 flight hours were used during this mission leaving 94.1 hours

left for research use.