DETERMINATION OF MONTHLY WET AND DRY PERIODS IN SAUDI-ARABIA

A graphical procedure for assessment of wet- and dry-spell duration is proposed based on the monthly rainfall amounts, in order to depict th e change of period duration with their number within a given record le ngth. A linear regression formulation is described on a log-log plot b etween spell durations and numbers. The application of this methodolog y has been presented for 16 rainfall stations distributed over the ent ire Kingdom of Saudi Arabia Because the longest durations of wet and d ry periods occur once in the whole record length their predictions can be found from the double logarithmic graphs corresponding to occurren ce number one. It has been observed that the longest durations of wet periods occur in the south-eastern part of the Kingdom of Saudi Arabia , where highest elevations in the Kingdom are found However, the longe st dry spell durations occur in the central and eastern part of the co untry.