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<br />To be published in the proceedings of the <br />Fifth WMO Conf'trence on Weather Modtflcatlon and Applied Cloud Physics I <br />Beijing, China <br /> <br />PROGRAMME AL GHAIT - DESIGN AND EVALUATION OF A WEATIlER <br />MODIFICATION PROGRAM IN MOROCCO <br /> <br />A. Bensari, S. Benarafa, B. Loukah, M. Benassi, A. Mrabet <br />Direction de la Meteorologie Nationale, Minstere des Transports <br />Casablanca, Morocco <br /> <br />D. Matthews, J. Medina, C. Hartzell, T. Deshler* <br />U.S. Department of the Interior, Bureau of Reclamation <br />Denver, Colorado, U.S.A. <br />(*Present affiliation: University of Wymning, Laramie, Wyoming, U.S.A.) <br /> <br />1. INTRODUCTION AND <br />BACKGROUND <br /> <br />Programme AI Ghait was designed as an <br />emergency response to assist the Kingdom of <br />Morocco during a period of severe drought. <br />The project was initiated upon the request of <br />His Majesty King Hassan II in 1983 for <br />assistance from the United States. In May <br />1984, the U.S. Agency for International <br />Development (USAID) signed an agreement <br />with tbe Government of Morocco to initiate a <br />multiyear winter snowpack augmentation <br />project in Morocco. USAlD implemented the <br />project through a Participating Agency Service <br />Agreement (P ASA) with the U.S. Department <br />of the Interior. Bureau of Reclamation <br />(USBR). The USBR provided overall scientific <br />management. During the period August 1984 <br />to August 1988, a USBR scientific advisor <br />resided in Casablanca, Morocco. and <br />coordinated the technical assistance effort. In <br />addition. modem meteorological and <br />communication equipment were provided under <br />the agreement. <br />The objectives of the project are to <br />(a) implement a scientifically based cloud <br />seeding demonstration program for winter <br />precipitation augmentation over the upper <br />portion of the Oued Oum er Rbia Basin in the <br />High Atlas Mountains to help alleviate the <br />current drought conditions, assess the amount <br />of additional water produced in the <br />river/reservoir system as a result of the <br />demonstration program, and evaluate the <br />effects of increased winter precipitation on <br />runoff and its subsequent uses; (b) examine <br />cloud and precipitation processes to improve <br />the scientific basis of the demonstration <br />program. and obtain evidence of its physical <br />plausibility; (c) concurrent with the first two <br />objectives, transfer winter precipitation <br />augmentation technology through informal and <br />formal training to enable Moroccan personnel <br /> <br />to design, plan, implement, monitor, and <br />evaluate similar winter precipitation <br />augmentation projects over the mountainous <br />areas of Morocco; and (d) increase awareness <br />of the need for an improved water resources <br />management program in the Oued Oum er <br />Rbia Basin, and increase awareness of the <br />contribution that weather modification can <br />make to the water resources. <br /> <br />2. LOCATION AND CUMATOLOGY <br /> <br />Morocco is located on the northwest <br />comer of Africa. The region selected for the <br />target area is the Central High Atlas <br />Mountains at 31 to 33 ON and 5 to 7 oW with a <br />mean elevation of about 3000 meters mean sea <br />level. The High Atlas range extends from the <br />northeast to the southwest (generally 055 to <br />235 degrees) across Morocco. Therefore, with <br />westerly to northerly flow, orographic lifting is <br />most effective in producing clouds and <br />precipitation. This area receives about 500 to <br />1000 mm of precipitation annually, primarily <br />from November to May. Figure 1 shows a map <br />of the central part of Morocco and the <br />principal field site locations of equipment and <br />operations personnel. <br /> <br />3. OPERATIONAL PLAN <br /> <br />Preliminary studies of the available <br />rawinsonde, precipitation, and steamflow data <br />indicated that the target area should have <br />sufficient opportunities for cloud seeding with <br />silver iodide (AgI). To determine the <br />frequency of supercooled water and the <br />microphysical structure of precipitation, cloud <br />physics data were collected under USBR <br />contract with the University of North Dakota, <br />U.S.A., from January to April and October to <br />De:cember 1985. These flights indicated that <br />seedable conditions with supercooled liquid <br />water from 0.1 to 2.0 g m-l occurred frequently <br />