Climatology of the areal precipitation in Amman/Jordan

摘要

Data of the rainy seasons from 1956/1957 to 2005/2006 for 11 stations distributed over Amman area were analyzed. They were used to estimate the areal rainfall amount in Amman area; the annual data have a normal distribution with an average of 283.7 mm. The areal rainfall amounts varied from year to year, with a standard deviation (SD) of 72.9 mm and with a variation coefficient of 26%. The analysis of the areal rainfall over a 50-year period shows a decreasing trend (-0.4 mm/year), but with no statistical significance. The running means show two wet periods (1962/1963-1973/1974 and 1987/1988-1993/1994) and two dry periods that occurred in the beginning and the end of the study period. The amounts of water fall over Amman area ranged from 300 mm~3 to 870 mm~3. Despite these amounts, Amman suffers from water shortage which needs to be solved.