WAVE CLIMATE OF PEHUEN CO BEACH (SW BUENOS AIRES PROVINCE, ARGENTINA) DETERMINED USING IN SITU HIGH-FREQUENCY MEASURES

ROTH, A.; MAVO MANSTRETTA, G.M.; PERILLO, G.M.E.; VITALE, A.J.

SANTIAGO DE CHILE

Conferencia; 2022 Particles in the Americas Conference (PiA 2022); 2022

Particles in the Americas (PiA)

One of the main variables to be analyzed when studying sediment dynamics on beaches is the wave action because it has the most significant energetic activity and, therefore, the greatest sediment load capacity. The determination of wave climate is crucial to understand beach dynamics, the changes in their geomorphology. The latter is essential for the design of coastal developments and projects. On the other hand, due to the high-dynamic environment, in situ measurements of waves is significantly complex; the installation of equipment to withstand the conditions requires challenging design and maintenance. This work presents the installation of a coastal monitoring station developed to measure oceanographic variables in real-time and at high-frequency directly at the surf zone. At the same time, the data processing and analysis are described, which made it possible to obtain statistical results on the distribution of frequencies for wave heights and periods. Wave (height/period) and water level data were obtained from the EMAC (Estación de Monitoreo Ambiental Costero) Beach Station located on Pehuen Co beach (39°00′16”S 61°32′53.50”W). This station consists of a set of sensors deployed along a 150 m cross-section of the beach going from the subaerial zone on the upper beach to the mean low tide. Using a pressure sensor located at the end of the line, the water level, wave height, and period are recorded. All data is registered every 10 min and transmitted to the IADO server every 30 min via GPRS. The data were then processed using the openaccess software R Studio. At this stage, anomalous outliers were filtered concerning wave height and period. Subsequently, frequency histograms indicating the occurrence of climatic events were elaborated. In addition, monthly mean values were calculated. Finally, wave distribution was analyzed using 2D density plots attached to a matrix with occurrence values. The results indicate that wave heights generally do not exceed 100 cm, with wave heights between 20 and 40 cm being predominant. In relation to the period, they show a predominance between 3 and 5 s. Only a significant data density is observed, located at heights ranging from 10 to 50 cm and periods between 2 and 8 s. Besides, has a range of higher probability of occurrence = 0.3 < H < 0.4 and 3 < T < 6. The recording of wave data and subsequent analysis allowed characterizing the behavior of the heights and periods, concluding that the wave climate is mainly affected by a generation of local type waves.