Aegean Sea-Level Variability in the Past Half-Century Based on Tide Gauge Data

Yıl 2022, Cilt: 9 Sayı: 1, 162 - 169, 06.03.2022

Cem Şenduran Sedat Kabdaşlı

https://doi.org/10.30897/ijegeo.1014344

Öz

Global sea-level rise induced by global warming has been growing in importance as a research topic in the past few decades. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) has strongly emphasized a visually certain trend in the sea-level rise in the past two centuries. Many studies have addressed the trend in sea-level records, both in global and regional scale, as studying the trend renders it possible to make future predictions. The latest study of World Climate Research Programme Global Sea Level Budget Group determined the global sea-level rise between 1993-2018 as 3.1 mm/year. The Aegean as a regional sea is chosen for this study to compare if there are any similarities between the global tendency and the regional using tide gauge records of monthly mean sea-levels in selected 6 stations. The data used in this study were obtained from the Permanent Service for Mean Sea Level (PSMSL), which is an organization that collects and publishes tide gauge records from across the world. The gaps in the raw tide gauge data were imputed by Kalman filtering, the time series were decomposed by using STL decomposition and the loess smoothed trend lines were obtained. The data ranges of time series were divided into 2 segments (from 1969 to 1995 and from 1995 to the end date) and linear trends for each segment were determined as well as the whole duration for each station. Mann-Kendall, Cox-Stuart, and Spearman’s Rho tests were applied on the datasets to detect statistically significant trends. The sea-level trends varied for each station and depending on the segment taken into consideration. 2 negative and 2 positive trends were obtained for the first segment. Positive trends changing from 1.6 mm/year to 7.5 mm/year with an average of 3.7 mm/year were determined for the second segment’s results of all stations.

Anahtar Kelimeler

Sea-level rise, trend analysis, STL decomposition, Aegean Sea

Proje Numarası

BAP Proje No: 39779

Kaynakça

• Church, J. A., & White, N. J. (2006). A 20th century acceleration in global sea-level rise. Geophysical Research Letters, 33(1), 94-97. doi:10.1029/2005GL024826
• Church, J. A., White, N. J., Thorkild, A., Stanley Wilson, W., Woodworth, P. L., Domingues, C. M., . . . Lambeck, K. (2008). Understanding global sea levels: past, present and future. Sustainability Science, 3(1), 9-22. doi:10.1007/s11625-008-0042-4
• Cleveland, R. B., Cleveland, W. S., McRae, J. E., & Terpenning, I. (1990). STL: A Seasonal-Trend Decomposition Procedure Based on Loess. Journal of Official Statistics, 6(1), 3-33
• Dangendorf, S., Marcos, M., Müller, A., Zorita, E., Riva, R., Berk, K., & Jensen, J. (2015). Detecting anthropogenic footprints in sea level rise. Nature Communications, 6, 7849. doi:10.1038/ncomms8849
• Douglas, B. C. (1992). Global Sea Level Acceleration. Journal of Geophysical Research, 97, 699-706. doi:10.1029/92JC01133; doi:10.1029/9
• Foster, G., & Brown, P. T. (2014). Time and tide: analysis of sea level time series. Climate Dynamics, 45, 291-308
• Gehrels, R., & Garrett, E. (2021). Chapter 11 - Rising sea levels as an indicator of global change. In T. M. Letcher (Ed.), Climate Change (Third Edition) (pp. 205-217). Elsevier. doi:10.1016/B978-0-12-821575-3.00011-6
• Haigh, I. D., Wahl, T., Rohling, E. J., Price, R. M., Pattiaratchi, C. B., Calafat, F. M., & Dangendorf, S. (2014). Timescales for detecting a significant acceleration in sea level rise. Nature Communications, 5, 1-11. doi:10.1038/ncomms4635
• Holgate, S. J., & Woodworth, P. L. (2004). Evidence for coastal sea level rise during the 1990s. Geophysical Research Letters, 31(7), 2-5. doi:10.1029/2004GL019626
• IPCC. (2014). Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. [Core Writing Team; Pachauri, R.K.; Meyer, L.A. (ed.)]. Geneva, Switzerland: IPCC
• Jevrejeva, S., Grinsted, A., Moore, J. C., & Holgate, S. (2006). Nonlinear trends and multiyear cycles in sea level records. Journal of Geophysical Research, 111(9), 1-11. doi:10.1029/2005JC003229
• Marcos, M., & Tsimplis, M. N. (2007). Forcing of coastal sea level rise patterns in the North Atlantic and the Mediterranean Sea. Geophysical Research Letters, 34, L18604. doi:10.1029/2007GL030641
• Meli, M., Olivieri, M., & Romagnoli, C. (2021). Sea-Level Change along the Emilia-Romagna Coast from Tide Gauge and Satellite Altimetry. Remote Sensing, 13(1), 97. doi:10.3390/rs13010097
• Moritz, S., & Bartz-Beielstein, T. (2017). imputeTS: Time Series Missing Value Imputation in R. R Journal 9.1. doi:10.32614/RJ-2017-009
• Orlić, M., Pasarić, M., & Pasarić, Z. (2019). Mediterranean Sea-Level Variability in the Second Half of the Twentieth Century: A Bayesian Approach to Closing the Budget. In I. Vilibić, K. Horvath, & J. Palau (Eds.), Meteorology and Climatology of the Mediterranean and Black Seas. Birkhäuser, Cham: Pageoph Topical Volumes. doi:10.1007/978-3-030-11958-4_15
• Piecuch, C., Calafat, F., Dangendorf, S., & Jorda, G. (2019). The Ability of Barotropic Models to Simulate Historical Mean Sea Level Changes from Coastal Tide Gauge Data. Survey in Geophysics, 40, 1399-1435. doi:10.1007/s10712-019-09537-9
• PSMSL. (2021, January). Permanent service for mean sea level, data. Retrieved September 17, 2021, from http://www.psmsl.org/data/obtaining
• R Core Team. (2021). R: A language and environment for statistical computing. R Foundation for Statistical Computing. Vienna, Austria. Retrieved from http://www.r-project.org
• Talley, L., Pickard, G., Emery, W. J., & Swift, J. (2011). Descriptive Physical Oceanography: An Introduction (6th ed.). Boston, MA: Academic Press
• Tsimplis, M., Spada, G., Marcos, M., & Flemming, N. (2011). Multi-decadal sea level trends and land movements in the Mediterranean Sea with estimates of factors perturbing tide gauge data and cumulative uncertainties. Global and Planetary Change, 76(1-2), 63-76. doi:10.1016/j.gloplacha.2010.12.002
• Visser, H., Dangendorf, S., & Petersen, A. C. (2015). A review of trend models applied to sea level data with reference to the “acceleration-deceleration debate”. Journal of Geophysical Research: Oceans, 120(6), 3873-3895. doi:10.1002/2015JC010716
• WCRP Global Sea Level Budget Group. (2018). Global sea-level budget 1993-present. Earth Syst. Sci. Data, 10, 1551-1590. doi:10.5194/essd-10-1551-2018
• Woodworth, P. L. (1990). A search for accelerations in records of European mean sea level. International Journal of Climatology, 10(2), 129-143. doi:10.1002/joc.3370100203
• Woodworth, P. L., & Player, R. (2003). The permanent service for mean sea level: an update to the 21st century. Journal of Coastal Research, 19, 287-295