Targeting analysis of cloud seeding effects in the Santa Barbara cloud seeding program

Santa Barbara County Water Agency has administered a regional cloud seeding program since 1981 to augment local water supplies. Prior to the operational program, research on cloud seeding was done in the area between 1951 and 1977. Beginning in the 1998-1999 winter season the program has undergone several upgrades including the use of new state of the art ground-based generators, improved radar analysis software, and the adaptation of an improved cloud seeding targeting model. The targeting model has been described previously (Stone, 1998). It utilizes a three dimensional windfield generator, a temperature and cloud water field generator that are coupled with microphysics growth, plume dispersion and fall velocity routines to estimate where seeding effects occur in the program area. Surface data, including the ground-based aerosol release points, upper air data and NWS model products provide input. Output forecast products from the Rapid Update Cycle Model (RUC2, Benjamin, et.al, 1998) also allow a compact diagnostic model to be used in a pseudo-forecast mode with improved accuracy. A brief description of the program will given along with a discussion and comparison of the current modeling approach used in different modes.