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<br /> <br />".. <br />.~ ,.... <br /> <br />N <br /> <br /> <br /> <br />t <br /> <br />(, <br />\. <br />~ <br />~ <br />'It <br />" <br />A... <br />'It <br /> <br />u~ 10 10 .. 10 <br />lUl.llIETiIIS <br /> <br />1 RADAR <br />~ RAWINSOHD" <br />- PRIIoWlY WATERSHED <br />- SECONDNlY WATEIlSllED <br />. CITY <br /> <br />_ STREMIf'LOW CAUCES FOR <br />TARGEr AND COKTllOL <br />+OAII <br />. SEEDING GEIlERATOR <br />" ~ COURSE <br />. PRECIPITATION GAUGE <br />( RECOflDING) <br /> <br />Figure 1. - Map of central Morocco showing the location of principal project field sites. <br /> <br />during precipitation events. In 1986, one of the <br />Royal Moroccan Air Force King Air-100 <br />seeding aircraft was instrumented with a basic <br />cloud physics instrumentation package and data <br />acquisition system. The aircraft's availability <br />continues to provide the project with an <br />important data set for cloud physics research <br />(see Baddour et al., these proceedings.) <br />Seeding operations are conducted by <br />Morocco's National Meteorological <br />Organization Division of Research in <br />Casablanca. The project's operations team <br />consists of about 50 meteorologists, pilots, and <br />technicians located from Casablanca to <br />Khouribga, Beni Mellal, Azilal, and Kenitra. <br />One or two Royal Moroccan Air Force King <br />Air-IOO aircraft and seven ground-based AgI <br />nuclei generators are used for seeding. <br />Seedable clouds were defined as those <br />clouds where natural supercooled liquid water <br />existed with temperatures of cloud top from <br />generally -5 to -20 oc. The depth of <br />supercooled clouds should generally be greater <br />than 1 km; and for the Central High Atlas, <br />winds at 700 mb level should be from 220 to <br />360 degrees. A 2% solution of AGI and NaI <br />was used with a burn rate of 20 g hr'! in the <br />ground-based generators and 176 g hr,l in <br />aircraft wingtip generators. <br />The on-duty director in the Operations <br />Center at Khouribga directs airborne and <br /> <br />ground-based seeding operations and cloud <br />physics research flights using the 5-cm digital <br />weather radar with a 1.6-degree beam width <br />located 80 to 150 kIn north of the primary <br />target area. Project rawinsonde obs,ervations <br />are taken at Beni Mellal at 0000 and 1200 u.t.e. <br />each day and special 0600 u.t.c. and 1800 u.t.e. <br />soundings supplement synoptic data during <br />operations to provide the most current <br />information for decisionmaking, A detailed <br />operations plan outlines the specific decision <br />criteria (including suspension evaluation) and <br />operational procedures for all aspects of the <br />project from declaration of operational status <br />to seeding generator, radar, cloud physics <br />aircraft, and data management operations <br />(Ha.rtzell et aI., 1986). <br />A primary input to the selection of the <br />seeding aircraft flight path and the ground- <br />based generators used for operational seeding <br />is the latest analysis from the Atlas Targeting <br />Model, which incorporates rawinsonde wind <br />and thermodynamic information from Beni <br />Mellal and also Tissa when available (Loukah, <br />1986; and Benassi, 1988). The targ~~ting model <br />predicts the location and orientation of the best <br />aircraft seeding line; shows the plume from <br />each ground-based generator and the points of <br />nucleation; and estimates the areal coverage of <br />seeding impact on the ground. The model is <br />two dimensional; its domain extends 160 km in <br />