Annual and semi-annual variations of sea level at Jeddah, central coastal station of the Red Sea

Abstract

Analysis of monthly means of sea level averaged over a period of three years (1991-1993) at Jeddah reveals the presence of a semi-annual component in addition to the annual one. The variance explained by the two components are 20 % and 78% respectively. Their respective amplitudes are 8.7 and 17.3 cm. The two cycles are induced by the combined effect of wind stress and evaporation rate. The cross-shore stress is the most contributing factor to the annual variation of the sea level. In contrast the long-shore stress is the dominant factor in inducing the semi-annual cycle. The evaporation contributes

<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">more to the semi-annual component of the <span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:hiddenhorzocr;="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">sea <span style="font-size:14.0pt;line-height:115%; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">level than to the <span style="font-size:14.0pt; line-height:115%;font-family:" times="" new="" roman";mso-fareast-font-family:hiddenhorzocr;="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">annual one.</span></span></span></span>