Cloud Droplet Probe (CDP) and Two-Dimensional Imaging Probe (2DC) Al Cooper NCAR

CDP Measurements: Cloud droplet number concentration, 2-50  m droplet size distribution cloud liquid water content Performance and Data Status: No missing data Small (15%) adjustment to sample volume post-project, incorporated into final-release data

Comments on CDP Most cases of cloud droplets were during low-level passes from missed approaches Some exceptions: Response unknown in ice: Not designed to detect small ice Should provide some response to small symmetrical ice May have false response from large ice Recommendation: Don't trust this as a measurement of ice without further study

Data Example: Flight 18, ,000 ft, -15 C, dense cloud

2DC Measurements: Hydrometeor concentration Hydrometeor size distribution >25  m (>150  m) Hydrometeor images Performance and Data Status: Improved small-size performance; very clean data.l Data gaps: 2 nd half of Flight 14, all of 15, 16 Initial processing error corrected, changed concentrations slightly and size distributions significantly

Comments on the 2DC: There is uncertainty in concentrations of particles smaller than about 150  m because of uncertainty in probe depth-of-field. There are some good Cirrus penetrations showing ice images; see, e.g., Flight 3 (2000), Flight 5, Flight 17 (2130), and short segments of other flights. Ice water content tends to be small, most Ci cases, but occasionally about 0.2 g/m 3

Example: Flight 5, 1830 Cirrus 34,000 ft -50C

Example: RF03 Ice crystals encountered on two descents, first in only small amounts, but in significant concentrations and IWC for second Ice is in region just below tropopause, extending as far down as the descent for 2 nd (over Montana)