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. ,~.. . I- I-- I- l- I- - 100 - Fig, 4,3 shows isopleths of the percentages of occasions on which water droplets dominated over ice particles on the continuous particle sampler. The curves are based on 145 runs of the continuous particle sampler taken during nine flights (the same seven flights as those mentioned in above paragraph plus post-frontal situations on December 28, 1970, and March 11, 1971), These 1- results provide general confirmation of the features shovm in Fig. 4.1 and 4.2. 4.2 Characteristics of Ice Particles Collect~d in Clauds+ l- I- ,.. l- I- 1- I:~ Ice cr'~/stals in clouds were collected and replicated using the continuous particle sampler at temperatures between 0 and -40oC. The crystal types gen(;\;':_\~~ly s1.-';.)port the classification scheme for Il3.tural ice epjstals proposed by r1agono and Lee (1966), but some differences were noted, The principal resn,l':;" are summarized below. For completeness some of the observations on snow crystals collected at ground level in the Cascades are also mentioned although these are discllssed at greater length in !i5. ,-, 4.2.1 Needles (NIa, NIb, N2a)A Acc.ordirlp: to l'IiiJ.gono and Lee: (195G) and Uno (1970) n'~edles grow in the temperature range between -4 to -60C under water-saturated conditions, The needles sampled by Ono (1970) hc:,d a J_imitin,i! a-m:is diii,::msion of 60 f.[m. I- I- l- I- I-!owever, needles lOY'.ger than about 5(:C) )Jm were not rec(ll'c1ed. The observations of Auer and Veal (1970) suggest that need10s do not reach a Lrniting diameter, but continue to increase with increasing length, tror reasons of economy we have not included photographs of the many different types of ice particles discussed in this section, .'. "The symbols used for the different types of ice particles are those proposed by Magono and Lee (1966), l- I-