Water heights and weather regimes at Alexandria Harbor

Abstract

The response of water level variations to the changes in local meteorological elements (atmospheric pressure, air temperature and wind force) has been investigated for Alexandria harbor over 11 years period (1995 to 2005). The study has shown clearly a close connection between them. The coherence is noted and the linear effect is discussed. The result of the regression technique indicated an increase of water level by 1.4 cm for each decrease of 1 mb of atmospheric pressure, and the water rises by 1.1 cm for each increase of air temperature by 1°, while it changes by 0.5 cm for each 1 knot of NW wind. The general pattern of water levels is illustrated and a marked seasonal trend is appeared. The most pronounced frequency of monthly water level distributions is concentrated in the level of 55 cm, and a sea level rise has occurred at a mean rate of 0.03 cm/year during the study period. Estimation of the generalized correlation indicated that the wind force induce 17% of the total variations on water levels, while air temperature have contribution to about 45% and the local atmospheric pressure are responsible for 16%. Key words: Meteorological elements, water levels, atmospheric pressure, air temperature, wind force.