APPLICATION OF BUSINGER-DYEAR AND BRUTSAERT'S STABILITY FUNCTIONS FOR ESTIMATION OF THE SENSIBLE HEAT FLUX ON SOME MEASURED DATA IN THE HADA AL-SHAM AREA, MAKKAH, SAUDI ARABIA

Micrometeorological measurements on the Hada Al-Sham region near Makkah were used for determination of the fluxes of sensible heat and momentum by applying profile method derived from Monin-Obukhov similarity theory. Samples of data were selected in a very unstable conditions (summer seasons) in the Hada Al-Sham area, Makkah. Two code programs written according to both Brutsaert (1992) and Businger-Dyear were used. Sensible heat values using the stability correction functions used by Businger-Dyer (B-D-F) were found to be higher (10-14%) than the stability correction functions used by Brutsaert (B-F) between 1100 and 1700 hours (noon and afternoon) on days of September 2002 and June 2003.  The roughness lengths Z₀ show higher values (0.3-0.5m) using (B-F) on most days for the easterly and SE winds due to the effect of very high rough area (medium height buildings, hills).  The roughness length Z₀ was found to be related with wind direction.  It was noticed from the experiment that the roughness length using the stability correction functions by (B-F) and was more sensitive to any change in wind direction than that used by (B-D-F).  The more the sudden change of the wind direction by (B-F) version the more the fluctuations in the roughness length values occure.
     Finally, the stability correction functions used by (B-D-F) for calculating sensible heat fluxes and stability parameters are more preferable than using the stability correction functions by (B-F) one.