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551 results on '"Hesp, Patrick A."'

12. Impact of coastline orientation on the dynamics of foredune growth (Łeba Barrier, south Baltic Sea coast, Poland)

Author

Dłużewski Maciej, Dłużewska Joanna Rotnicka, Hesp Patrick Alan, Tomczak Joanna Oliwia, and Dubis Lidiya

Subjects
foredune, wind regime, fetch distance, coastline orientation, potential aeolian transport rate, sediment budget, Geography (General), G1-922
Abstract

There are many factors controlling the aeolian sand transport rate on the beach and thus, variation in rates can impact foredune development. This study analyses coastline orientation as one such factor. The research was conducted at two sites on the Łeba Barrier, south Baltic Sea coast, Poland, located 4.2 km apart and which differed in coastline orientation by 20°. Based on wind data the potential aeolian sand transport rate for the period 2006–2017 was calculated. It appeared that taking into account the coastline orientation, the landward sand transport strongly exceeded the seaward and alongshore transport at one site, whereas the other site was dominated by alongshore sand transport. Topographic surveys carried out every 6 months showed that net sand deposition within the foredune at the coast dominated by landward transport was two and a half times greater than at the other site and resulted in significant dune growth.

Published
2023
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37. Impacts of large scale climate modes on the current and future bimodal wave climate of a semi-protected shallow gulf

Author

Perry, Benjamin (author), Huisman, Bas (author), Antolínez, José A. Á. (author), Hesp, Patrick A. (author), Miot da Silva, Graziela (author), Perry, Benjamin (author), Huisman, Bas (author), Antolínez, José A. Á. (author), Hesp, Patrick A. (author), and Miot da Silva, Graziela (author)

Abstract

The bimodal wave climate of the semi-protected shallow Gulf St Vincent in South Australia has been analyzed through a forty-year (1980-2020) wave hindcast and an investigation into the climatic drivers of wave climate anomalies is presented. The sea and swell partitions of the wave climate were modelled independently as well as using an integrated model with both partitions represented. The wave hindcast was validated against two wave buoys located off the coast of Adelaide’s metropolitan beaches and key wave parameter anomalies were calculated across the gulf. Teleconnections were investigated, and the Southern Annular Mode is found to have the strongest correlations to wave parameter anomalies while the Southern Oscillation Index and the Dipole Mode Index fluctuations are found to correlate seasonally with wave parameter anomalies. Projected future trends of these climate drivers from literature have been related to the teleconnections found in this study to inform future trends of bimodal wave conditions in the gulf. The Southern Annular Mode is projected to trend positive which will reduce wave height and the westerly component of waves in the gulf, while the Southern Oscillation Index is projected to become more variable in the future which will lead to more extreme winter and spring wave conditions. An understanding of these trends allows coastal managers to pre-emptively manage the impacts of waves on the coastline at a seasonal to annual basis and provides insight into future wave conditions beyond these time periods., Coastal Engineering

Published
2024
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38. UAV‐SfM‐based field quantification of barchan dune celerity and morphodynamics in Gonghe Basin.

Author

Shao, Mei, Luo, Wanyin, Che, Xuehua, Hesp, Patrick A., and Bryant, Robert G.

Subjects
SAND dunes, PREDICATE calculus, AIR flow
Abstract

Barchan dunes do not often coexist with grasslands. However, in Gonghe Basin, north‐eastern part in Qinghai‐Tibetan Plateau (QTP), China, many barchan dunes are distributed on the grassland at high altitude. Identifying celerity and morphodynamics of barchan dunes and exploring the interaction between barchans and grassland landscape can help us better understand aeolian system sand mitigate damages. In this work, we tracked dune celerity and observed three‐dimensional changes of symmetrical and asymmetrical barchan dunes in Ertala based on high‐resolution UAV‐SfM reconstruction in short‐term monitoring and discussed the factors influencing dune celerity and deformation at high altitude. The results revealed that the barchan dunes are highly mobile with an average celerity of 0.85 m/M for the whole study area. Based on observations of dune morphology and dynamics, we found the following: (1) The dune deformation degree in a short time is not large but is widespread, especially in the elongated arm of asymmetric dune. The deformation of symmetric dune is symmetrical, whereas that of dune with extended horn is asymmetrical; (2) the sand supply, vegetation and airflow at low air density all influence the celerity and deformation degree in the development of barchan dunes; (3) the asymmetric airflow and sediment supply are important cause of dune asymmetry. The above results help us understand the deformation of barchan dune from the three‐dimensional, especially the difference reflected by the symmetry of barchan dune at high altitude. [ABSTRACT FROM AUTHOR]

Published
2024
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