Global distribution of nearshore slopes with implications for coastal retreat

Panagiotis Athanasiou*, Ap Van Dongeren, Alessio Giardino, Michalis Vousdoukas, Sandra Gaytan-aguilar, Roshanka Ranasinghe

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

31 Citations (Scopus)
53 Downloads (Pure)


Nearshore slope, defined as the cross-shore gradient of the subaqueous profile, is an important input parameter which affects hydrodynamic and morphological coastal processes. It is used in both local and large-scale coastal investigations. However, due to unavailability of data, most studies, especially those that focus on continental or global scales, have historically adopted a uniform nearshore slope. This simplifying assumption could however have far-reaching implications for predictions/projections thus obtained. Here, we present the first global dataset of nearshore slopes with a resolution of 1 km at almost 620 000 points along the global coastline. To this end, coastal profiles were constructed using global topo-bathymetric datasets. The results show that the nearshore slopes vary substantially around the world. An assessment of coastline recession driven by sea level rise (SLR) (for an arbitrary 0.5 m SLR) with a globally uniform coastal slope of 1 : 100, as carried out in previous studies, and with the spatially variable coastal slopes computed herein shows that, on average, the former approach would underestimate coastline recession by about 40 %, albeit with significant spatial variation. The final dataset has been made publicly available at (Athanasiou, 2019).
Original languageEnglish
Pages (from-to)1515-1529
Number of pages15
JournalEarth system science data
Issue number4
Publication statusPublished - 2 Oct 2019


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