May 14, 1998

{return}

Crew: Streibel, Miller, Arnott, Poellot

145700 Taxi. Stratus overcast with cirrus above. Cirrus mission.

150100 Holding for departing traffic in front of us. Note: times on the data system are about 2 seconds slow. It is hazy, reduced visibility. Pressure altitude at surface is 329 m.

151610 Takeoff. Base of clouds at 800 m, but can still see ground at 900 m. Getting a few counts in first couple channels of FSSP. Few lower clouds.

152300 Climbing in between layers. Lower layer is thin. Cirrus above is nearly overcast and fairly dense. No halo.

152440 CART reports base of cirrus at 33,000’, tops at 40,000’.

152641 CART, 14,500’, climbing, not in cloud.

153230 The EG&G dew point is warmer than cryo. Cryo balances good now.

153323 CART, 23,800’, not in cloud.

153640 In cloud at 27,300’, aggregates to 1 mm.

153655 CART, climbing through 27,800’. In spiral climb.

153910 Shadow/or concentrations about 50/L, particles are 100-300 m m. Winds at 30,500’ are 240/56.

154141 CART, 31,400’, in cloud. S/Or about 35/L.

154347 Almost at top of layer with scattered, thinner cloud above.

154600 Back in cloud — we were out for a short time.

154800 Just passed CART. In very thin cloud, or perhaps not in cloud. There are higher patches around us. The cloud top here is not uniform.

154953 Back in cloud. Level at 35,000’. T = -51 ° C. Stuck at this level for traffic.

155200 The EG&G is reading too warm, the cryo is good. The LiCor maxed out at about —42 ° C.

155325 CART, level 35,000’.

155500 Balancing EG&G.

155600 Still at 35,000’ for traffic. We seem to be in cloud on the downwind leg not over CART, and then upwind over CART not in cloud. The particles are kind of irregular, but running 200-500 m m.

155820 Cleared to climb. Winds are 230/46.

155908 CART, 35,600’, climbing.

160602 CART, 37,100’, just at or out of cloud top, a fewer higher wisps ahead and to our right which is to the northwest.

161120 At 38,000’. Just barely into very thin cirrus, on top of most all of it. We’re going to start a spiral down next.

161239 CART, 38,000’. Start spiral down. Back into cloud top at about 37,000’.

161430 Adjusting descent rate.

161620 Photo of contrail. Temporarily out of cloud.

161759 CART.

162010 In and out of cloud so far. Still descending, through 30,800’.

162213 CART, descending through 28,900’, back in cloud. Larger particles at this altitude, up to 800-900 um.

162615 or 20 Passed over CART at 26,000’. In ice crystal fallout near cloud base. Next we’ll do step up. Underlying stratus undercast is extensive.

162730 We came out of cloud southwest bound past CART. Getting ready to begin step up.

163140 Near CART at 27,000’.

163635 Ran out of cirrus heading back to CART at 28,000’. There are still higher patches ahead.

163745 CART, 28,000’, not in cloud. We may step up more than 1000’ this time. Looking upwind to southwest, there are about 2 bands of cirrus and then some clear sky.

164155 The cirrus that is left — the lower one is still 7 miles upwind of CART. Seeing a halo from the higher layer.

164?15 Headed back to CART, still at 29,000’ for traffic.

164433 CART. Just coming up on the lower band of cloud at 29,000’. The band is just upwind of CART.

165218 CART, 31,000’. The higher band has just moved off downwind.

165550 Dropping to 29,000’. We were just above a layer at 30,000’.

165756 CART, 29,000’, not in cloud. Cloud patch behind, cloud patch ahead.

170322 CART, not in cloud. Next patch is still just upwind. We’re going to go back up to 30,000’ and try to catch it as it comes by. We had sampled it at 29,000’ after we had turned around to head NE. Now turning around to head SW.

170856 CART, 30,000’, not in cloud.

171040 Climbing to 31,000’. There is a higher patch moving over — we’ll see if we can get into that.

171440 Passed by about a mile south of CART, 31,000’. We had hit a patch of cirrus upwind.

172004 Back in cloud, at 31,000’, heading SW 2miles from CART.

172145 CART, not in cloud.

172607 CART, 32,900’, not quite in cloud (may have just gotten into it).

172630 The INS quit. This means we will not have winds, but the rest of the data should be OK.

173246 CART, 33,000’. Not in cloud. There is another band at our altitude upwind.

173545 Several pictures of overflying aircraft contrails. Circling, waiting for this next cloud patch to move in.

174540 Getting back into cloud at 33,000’, approaching CART.

174649 CART, 33,000’, in cloud. Small particles 100-300 m m, 40-50/L. Halo.

175230 Just by CART at 33,000’, in cloud, fairly dense, small particles 100-200 m m, 50/L. T = -45 ° C.

175847 CART, in cloud, 32,000’. Particles somewhat larger here, 300-800 m m. Looked like a branched crystal — bullet rosettes? Halo.

180357 CART, 31,000’, in cloud. 200-400 m m, a few larger, 40/L. Up to 800 m m on 1DP.

181010 CART, 30,000’, in cloud. Aggregates, rosettes.

181400 Just turned around, heading back NE for last run, at 29,000’. We’ve gone out the SW side of the cirrus patch. We’ll be coming back into as we get towards CART.

181543 CART, 29,000’, in cloud. Last run.

182625 Turned off 2DC — condensation on optics.

183121 Landing

3.3 hours

3+15 minutes.