SOLAR IRRADIATION MEASUREMENTS IN JORDAN AND COMPARISONS WITH CALIFORNIAN AND ALPINE DATA

In order to obtain reliable irradiation data for the design, operation and economic assessment of solar power stations, a measurement campai gn has been performed in Jordan. As promising sites the desert near Qu wairah in the South of Jordan, the stony desert South East of Amman an d the elevated plateau near Naqb and also in the South of Jordan were chosen. Measurements were performed during the period of June 1989 to July 1992. The data were evaluated and compared with data of Bal stow, California and the Swiss Alps, From the yearly sums of the direct nor mal irradiation in 1990 and 1991 at Quwairah (2701 and 2436 kWh/m(2) r espectively) it is concluded that this site is comparably as good for solar thermal power stations as the Barstow site. The global normal ir radiation (usable with sun-tracked photovoltaic panels) had the surpri singly high values of 3551 and 3373 kWh/m(2) in 1990 and 1991 respecti vely. Occasionally peak values of the global normal irradiation greate r than the solar constant were measured (up to 1500 W/m(2)). Missing g lobal normal data from other arid sites do not permit comparison. As k nown before, the corresponding values in the Swiss Alps are considerab ly lower (1100-1700 kWh/m(2) for the direct normal ir radiation and 20 00-2500 kWh/m(2) for the global normal irradiation respectively, depen ding on the year and site). In addition to the direct normal and globa l normal irradiation, the global horizontal and global inclined (30 de grees South) irradiation were measured, amounting to 2353 and 2499 kWh /m(2) respectively in 1990. Data have also been collected on wind, rai nfall, ambient temperature, dew point and surface pressure. All data a re available in a computer accessible form, in particular as a yearly set of 5 min mean values of the direct normal irradiation for 1990. Co mbining the ground measured data with METEOSAT-data resulted in a uniq ue map of the dir ect normal irradiation for Jordan and surrounding co untries, indicating attractive sites for solar power stations. The mea surement campaign was made possible by active support from the Ministr y of Energy and Mineral Resources, MEMR and the Jordan Electricity Aut hority, JEA, both at Amman, as well as by generous financial support o f the Swiss Committee for Scientific Research, KWF, Berne.