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<br />4. aircraft measurements on the feeder cloudi including: <br /> <br />- meteorological and position keeping parameters <br />- number and size of water droplets and ice particles <br />- estimated cloud base characteristics <br /> <br />5. continuous S-band radar observations <br /> <br />6. Surface precipitation information from an extensive volunteer <br />reporting network <br /> <br />7. time-resolved hailstone samples <br /> <br />8. Time-integrated hailstone samples from an extensive volunteer network <br /> <br />3.1.1.2 Closed data sets <br /> <br />Closed data sets were selected to test model reliability without readjusting <br />or fine tuning models to each case. While no two cases are ever identical in <br />nature, similar cases were chosen for the open and closed data sets of each <br />experiment. Note that there are no closed data sets available for the liquid <br />microphysics cases (GATE 226 and 261). <br /> <br />3.1.2 Orographic case <br /> <br />3.1.2.1 Open data set - COSE (Rocky Mountain Orographic Cloud System) - <br />January 5, 1982 <br /> <br />This case occurred during the superposition of a large scale, pretrough cloud <br />system on a well established orographic cloud over the Park Range of Colorado. <br />Analysis of this system indicates a transition from an orographic cloud with <br />high liquid water contents to a cloud system primarily composed of ice. <br />Precipitation evolved through four stages: (1) a period of orographic precipi- <br />tation prior to synoptic forcing, (2) synoptic frontal precipitation with <br />increasing rate of precipitation, (3) a quasi-steady state period, and (4) a <br />dissipitating period of the storm. This case is described by Rauber and Grant <br />(1982) and Blumenstein et al. (1983). <br /> <br />In general precipitation did not form efficiently in the early stage, high <br />liquid water content cloud, where few ice c~ystal were present. As availability <br />of moisture and the number of ice crystals increased with the onset of the <br />synoptic disturbance, liquid water was quickly consumed and crystal growth pro- <br />cesses operated efficiently to produce heavy precipitation in the region. <br /> <br />17. <br />