Benkler, Anna S.

Menéndez García, Melisa

UCrea

Geophysical Research AbstractsVol. 19, EGU2017-16995, 2017EGU General Assembly 2017© Author(s) 2017. CC Attribution 3.0 License.Examining global extreme sea level variations on the coast from in-situand remote observationsMelisa Menendez (1) and Anna S. Benkler (2)(1) Environmental Hydraulics Institute (IHCantabria). Universidad de Cantabria, Santander, Spain. , (2)Christian-Albrecht-University (CAU). Kiel, GermanyThe estimation of extreme water level values on the coast is a requirement for a wide range of engineering andcoastal management applications. In addition, climate variations of extreme sea levels on the coastal area resultfrom a complex interacting of oceanic, atmospheric and terrestrial processes across a wide range of spatial andtemporal scales.In this study, variations of extreme sea level return values are investigated from two available sources of informa-tion: in-situ tide-gauge records and satellite altimetry data.Long time series of sea level from tide-gauge records are the most valuable observations since they directlymeasure water level in a specific coastal location. They have however a number of sources of in-homogeneitiesthat may affect the climate description of extremes when this data source is used. Among others, the presenceof gaps, historical time in-homogeneities and jumps in the mean sea level signal are factors that can provideuncertainty in the characterization of the extreme sea level behaviour. Moreover, long records from tide-gaugesare sparse and there are many coastal areas worldwide without in-situ available information. On the other hand,with the accumulating altimeter records of several satellite missions from the 1990s, approaching 25 recordedyears at the time of writing, it is becoming possible the analysis of extreme sea level events from this data source.Aside the well-known issue of altimeter measurements very close to the coast (mainly due to corruption by land,wet troposphere path delay errors and local tide effects on the coastal area), there are other aspects that have tobe considered when sea surface height values estimated from satellite are going to be used in a statistical extrememodel, such as the use of a multi-mission product to get long observed periods and the selection of the maximasample, since altimeter observations do not provide values uniform in time and space.Here, we have compared the extreme values of ’still water level’ and ’non-tidal-residual’ of in-situ records fromthe GESLA2 dataset (Woodworth et al. 2016) against the novel coastal altimetry datasets (Cipollini et al. 2016).Seasonal patterns, inter-annual variability and long-term trends are analyzed. Then, a time-dependent extrememodel (Menendez et al. 2009) is applied to characterize extreme sea level return values and their variability on thecoastal area around the world.

Examining global extreme sea level variations on the coast from in-situ and remote observations

https://repositorio.unican.es/xmlui/bitstream/10902/13759/3/ExaminingGlobalExtreme.pdf

Examining global extreme sea level variations on the coast from in-situ and remote observations

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