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8 I I I. I I I I I I, I I I I 1 1 I I I I and mesoscale oharacteristics. The major component of the cloud physios research associated with natural and seeded storms during CENSARE was an empirical assessment of accretion microphysics by Reinking (1973). This work was later summarized by Reinking (1975, 1979). Reinking found that heavy rime and graupel formation were common to all stages of Sierra storms, accounting for at least half the mass of the total precipitation. In cases where deep, cold clouds were present (based on rawinsonde analysis), few crystals observed by Reinking had the bulk of their diffusional growth occur at temperatures colder than -200C. Reinking determined that clouds must have non~uniform liquid water contents and that the bulk of the supercooled water was located at temperatures warmer than -10oC. In his habit classifioation, needles and sheaths account for half the total precipitation sample. Concentrations of crystals nucleated at temperatures warmer than ~20oC were SUbstantially greater than the natural nuclei spectra would suggest, with crystal concentrations increasing toward warmer temperatures. Crystal concentrations were found to exceed natural nuclei by 3 to 4 orders of magnitude. However, some unoertainty was introduced in the Reinking study concerning the origin of these crystals since 8 of the 9 storms examined by Reinking were seeded. Reinking provided an extensive climatology of the accretion process in Sierra atorms. His results are discussed in Chapter 4. (2) CAWRP The C~~ca~e_P!~~~am was the only large weather modification p~~~!~ prior to 1977 that emphasized study of the natural cloud struoture prior to any attempts at modification. It was also the only program whioh had ~~-~..,- no statistioal component. A detailedreyj,ew Of the. program.is conta4,ned. ."r--- -'~ _~.._.__.._._.-f