Sea Level Characteristics Referenced to Specific Geodetic Datum in Alexandria, Egypt
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 33090
Sea Level Characteristics Referenced to Specific Geodetic Datum in Alexandria, Egypt

Authors: Ahmed M. Khedr, Saad M. Abdelrahman, Kareem M. Tonbol

Abstract:

Two geo-referenced sea level datasets (September 2008 – November 2010) and (April 2012 – January 2014) were recorded at Alexandria Western Harbour (AWH). Accurate re-definition of tidal datum, referred to the latest International Terrestrial Reference Frame (ITRF-2014), was discussed and updated to improve our understanding of the old predefined tidal datum at Alexandria. Tidal and non-tidal components of sea level were separated with the use of Delft-3D hydrodynamic model-tide suit (Delft-3D, 2015). Tidal characteristics at AWH were investigated and harmonic analysis showed the most significant 34 constituents with their amplitudes and phases. Tide was identified as semi-diurnal pattern as indicated by a “Form Factor” of 0.24 and 0.25, respectively. Principle tidal datums related to major tidal phenomena were recalculated referred to a meaningful geodetic height datum. The portion of residual energy (surge) out of the total sea level energy was computed for each dataset and found 77% and 72%, respectively. Power spectral density (PSD) showed accurate resolvability in high band (1–6) cycle/days for the nominated independent constituents, except some neighbouring constituents, which are too close in frequency. Wind and atmospheric pressure data, during the recorded sea level time, were analysed and cross-correlated with the surge signals. Moderate association between surge and wind and atmospheric pressure data were obtained. In addition, long-term sea level rise trend at AWH was computed and showed good agreement with earlier estimated rates.

Keywords: Alexandria, Delft-3D, Egypt, geodetic reference, harmonic analysis, sea level.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1315759

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1360

References:


[1] Pugh, D., 1987. Tides, Surges and Mean Sea Level. John Wiley and Sons Ltd.
[2] Davidson, M., Edwing, R., Blackwell, J., Lowell, J., 2012. Incorporating sea level change scenarios at the local level. NOAA Coastal Services Centre, USA.
[3] Jorda, G., Gomis, D., Alvarez-Fanjul, E., Somot, S., 2012. Atmospheric contribution to Mediterranean and nearby Atlantic sea level variability under different climate change scenarios. Global Planet. Change 80–81, 198–214.
[4] Cole, J. (1939): Revision of first order levelling Lower Egypt, Survey Department Paper No.44, Egyptian Survey Authority, Giza, Egypt.
[5] United kingdom Hydrographic Office (UKHO), (2015): “Admiralty Tide TABLEs NP202, volume 2, TABLE IV, Height in meters of chart datum relative to the land levelling system in countries outside the united kingdom, Mediterranean sea and atlantics ocean, England.
[6] IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)), Cambridge University Press, United Kingdom and New York, USA, 1535 pp.
[7] Boko, M.; Niang, I.; Nyong, A.; Vogel, C.; Githeko, A.; Medany, M.; Osman-Elasha, B.; Tabo and R.; Yanda, P. (2007) “Climate Change 2007: Impacts, Adaptation and Vulnerability”, In Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental, by M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. Van der Linden and C.E. Hanson, 433-467. Cambridge: Cambridge University Press.
[8] El-Geziry, Tarek, Radwan, Ahmed, 2012. Sea level analysis off Alexandria, Egypt. Egyptian Journal of Aquatic Research (2012) 38, 1–5.
[9] Sharaf El-Din, S.H., 1975. Variation of sea level on Egyptian Mediterranean and Red Sea. International Hydrographic Review52 (1), 63–73.
[10] Eid, F. M. (1990); "Variation of surge heights at Alexandria Port, Egypt”, J. KAU., Mar. Sci., vol. (9): pp. 1-18.
[11] Saad, N.N., Moursy, Z.A., Sharaf El-Din, S.H., 2011. Water heights and weather regimes at Alexandria Harbor. International Journal of the Physical Sciences 6 (30), 7035–7043.
[12] Faisel, H., (2005): “Realization and Redefinition of the Egyptian Vertical Datum Based on Recent Heterogeneous Observations”, PhD thesis, Shoubra Faculty of Eng., Giza, Egypt.
[13] Tsimplis, M.N., Calafat, M.F., Marcos, M., Jordà, G., Gomis, D., Fenoglio-Marc, L., Struglia, V.M., Josey, A.S., Chambers, P.D., (2013): “The effect of the NAO on sea level and on mass changes in the Mediterranean Sea”, J. Geophys. Res., 118, 1-9.
[14] Tonbol, K.M., and Shaltout, M. (2013). Tidal and non-tidal sea level off Port Said, Nile Delta, Egypt. JKAU: Mar. Sci., Vol. 24, No. 2, pp: 69-83 (2013 A.D. / 1434 A.H.), DOI: 10.4197/Mar. 24-2.5.
[15] El-Geziry, Tarek, 2013. General pattern of sea level variation in front of Alexandria (Egypt) and its relationship to the wind pattern. Egyptian Journal of Aquatic Research (2013) 39, 133–139.
[16] FIG Commission 4 Working Group 4.2. FIG Guide on the Development of a Vertical Reference Surface for Hydrography. Technical Report 37, The International Federation of Surveyors (FIG), Frederiksberg, Denmark, 2006.
[17] Altamimi, Z., P. Rebischung, L. Métivier, and X. Collilieux (2016), ITRF2014: A new release of the International Terrestrial Reference Frame modeling nonlinear station motions, J. Geophys. Res. Solid Earth, 121, 6109–6131, doi: 10.1002/2016JB013098.
[18] Delft3D-FLOW (2015): Simulation of multi-dimensional hydrodynamic flows and transport phenomena, including sediments User Manual Hydro-Morph dynamics, Version: 3.15, 24 October 2015.
[19] Pugh, D. T. (1996); “Tides, surges, and mean sea level’, Great Britain, Antony Rowe Ltd, Chippenham, Wiltshire.
[20] Pugh, D., 2004. Changing Sea Levels: Effects of Tides, Weather and Climate. Cambridge University Press, UK.
[21] Rady, M. A. (1979); “Variation of sea level at Alexandria and its relation to the meteorological conditions”, M.Sc. thesis, Faculty of science, Alexandria, Egypt.
[22] Moursy, Z. A. (1989); “Meteorological aspects of Storm surges at Alexandria coastal water”, Ph D. thesis, Faculty of science, Alexandria University, Egypt.
[23] Moursy, Z. A. (1996) Sea temperature contribution to sea level at the southeast sector of the Mediterranean. Oebalia, XXII: 131-137.
[24] Hicks, S., Sillcox, R., Nichols, C., Via, B., McCray, E., 2000. Tide and Current Glossary. National Ocean Service. US Department of Commerce, USA.
[25] Doodson, A. T., 1954. Appendix to circular-letter 4-H. The harmonic development of the tide-generating potential. International Hydrographic Review 31, 37–61.
[26] Sharaf El-Din, S. H., Ezzat, A., (2007): “Marine impact of extension of coastal road on the transformation of materials of the near shore marine environment”, international conference of urbanization rabid organization and land use conflict in coastal cities 30 October – 1 November 2007, Aqaba Jordan.
[27] Moursy, Z.A., 1994. Seasonal fluctuation of surge height at Alexandria Egypt. Bulletin National Institute of Oceanography & Fisheries 20 (1), 33–42.
[28] Alam Eldin, Saad M. Abdelrahman, and M. El Meligy (2007). Seasonal and long term variations of sea level and meteorological conditions along the Egyptian coasts. Proceedings of the 8th International Conference on the Mediterranean Coastal Environment, MEDCOAST 07, E. Ozhan (Editor), Alexandria, Egypt.
[29] Shaltout, M., Tonbol, K.M. and Omstedt, A. (2015). “Sea-Level Change and Projection for Future Flooding along the Egyptian Mediterranean Coast,” Oceanologia (2015) 57, 293-307, https://doi.org/10.1016/j.oceano.2015.06.004.