Flight report, Second ACE-1 Research Flight

2 November, 1995

1859    Blocked out

1907    Takeoff, Anchorage, northbound climb
1929    Passed 20,000'
1934    Level at 22,000'
2031    Entered thick, persistent, dry cloud
2106    Croossed Alaska shoreline to Beaufort Sea

2136    Began sounding to 200'
2158    Level at 200' above the ice for 30 min
2228    North of 75N, began climb and turned southward
2232    Level at 3800' for 30 min, 300' above cloud deck
2302    Sounding to 26,000'in progress to Anchorage

2340:15 Level at 26,000', near the top of an ice cloud
0050    Emerged from cloud                                                
0132:35 Sounding from 26,000'
0148    Level at 9000'for a Tanner calibration
0157:45 End of 9000' leg, descended to Anchorge

0214    Landed Anchorage
0219    Blocked In

Something strange ocurred with the CAI, since the apparent INTAS1 (speed in the shroud) was 374 m/s at 1946, while the TASX was only 151 m/s. The sampling- plane speed was pretty consistently 10% of TASX, or 15.2 m/s at the high altitudes. INPDIFF wandered a lot, in the vicinity of 150 mbar, even when the airspeeds were constant.

The lidar was out of convergence early in the flight, but supplied useful data f from about 2022. It was showed us the extent of clouds above us (and the futility of trying to climb above them in some cases), and assured the pilots that there was clear air beneath the low clouds over the ice, so it was worth penetrating them to sample below.

The Clarke DMA wasn't working, and Russell's lost some data due to a lack of disk space. This data will be essential to resolve discrepancies between Weber's and Litchy's UCN observations: again, each occasionally saw high UCN when the other did not. Weber's were high more often, apparently. Since ground measurements and those on climbout agree fairly well, either a difference in plumbing (with losses in one or the generation of particles in the other) or sensitivity to certain size ranges must be the cause. Again, shattering of droplets in cloud caused Kik's in-cloud CN to exceed that of Litchy's similar instrument.

There were virtually no UCN in the MBL over the ice, but both systems saw significant UCN during the 9000' leg just prior to returning to Anchorage. Sulfuric acid was found on the high leg northbound (1-2x10+5 at 2027), just before penetrating the last clouds before the ice (~2155), and during the descent to 9000' (`0143). We need to look for possible coherence between UCN and H2SO4 observations. On the climb out from our BL legs, it was apparent that CN and dew point were anticorrelated: two aerosol layers were located in a dry layer.

The NO system operated much of the flight, collecting data as well as doing calibrations.

-Barry Huebert