Application of the local response method with weight function for Sea Surface Topography computations Case study: Persian Gulf



Sea Surface Topography (SST) by definition is the separation between the geoid and the Mean Sea Level (MSL). The separation between the geoid and MSL is caused by various non-gravitational physical effects. If determination of the geoid as the zero point of the height systems from the tide gauge observation be the goal, it is necessary that the affect of the physical effect be precisely computed and removed from MSL. One of the methods used for the study of physical response of a system to environmental effects in time domain is the “local response with weight function” or “impact response function” technique. The aforementioned function reveals the point-wise relation between the input and output of the physical system of interest, and in this way makes the point-wise modeling of the local variations of the system possible. In this study the weighted local response technique is used for SST computations in four tide gauge stations along the Persian Gulf, namely Shahid-Rajai Port, Kangan Port, Bushehr Port, Imam-Hasan Harbor, as well as the related meteorological stations. According to the numerical results, SST within the winter time in the studied stations varies between -82cm (in Bushehr Port) to +2cm (in Shahid-Rajai Port). The maximum SST value in Bushehr Port shows the reduction of the mean Persian Gulf level, while the minimum value of SST in Shahid-Rajai Port shows the rise of sea level due to SST in that area. This result is also in agreement with the geographical location of the two stations. Shahid-Rajai port being closer to the Oman Sea is dominantly affected by the topography of the Oman Sea and sea incoming currents to the Persian Gulf from the Oman Sea. Bushehr Port is farther away from the Oman Sea and as such is less affected by the Oman Sea currents. This finding is also reported in the previous studies over the region. Therefore, it can be concluded that SST computation using weighted local response technique is sufficienty accurate for the computation of SST and specially SST difference between the tide gauge stations.