TEMPORAL SHORELINE SERIES ANALYSIS USING GNSS

Francisco Jaime Bezerra Mendonça,Joseph Awange,Rodrigo Mikosz Gonçalves,Maria Das Neves Gregório,Luciana Maria Da Silva

doi:10.1590/s1982-21702014000300040

Francisco Jaime Bezerra Mendonça, Joseph Awange + Show 3 more

Open Access

https://doi.org/10.1590/s1982-21702014000300040

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Abstract

In recent decades, Boa Viagem beach located in the city of Recife-PE and Piedade in Jaboatão dos Guararapes-PE (Brazil) has seen urbanization near the coastline causing changes in social, economic and morphological aspects, where coastal erosion problems are observed. This study uses GNSS (global navigation satellite system) shoreline monitoring approach, which is quicker, and provides continuously updatable data at cm-level accuracy to analyze and determine temporal positional shifts of the shoreline as well as annual average rates through EPR (end point rate). To achieve this, kinematic GNSS survey data for the years 2007, 2009, 2010 and 2012 were used. The results show sectorial trends over the years, with the highest annual retreat rate of 8.16 m /year occurring during the period 2007-2009. Variety of differents patterns over the shoreline was also observed. These findings could be essential for decision making in coastal environments.

Highlights

A shoreline is one of the most dynamic geomorphological features of our planet
The shoreline monitoring is necessary for the purpose of integrating coastal zone management (ICZM), where the positional and dynamical information are fundamental for territorial planning, as well as for learning the process of coastal evolution providing information to protect, plan, and make decisions in relation to coastal environment (VELOSO-GOMES et al, 2008; TZATZANIS et al, 2003)
As a contribution to studies of monitoring of the shoreline based on GNSS techniques, this paper describes a consistent, low cost, and accurate monitoring approach that can detect different sectors with similar characteristics of evolution

Summary

Introduction

A shoreline is one of the most dynamic geomorphological features of our planet. Several studies involving its concept and modeling have been developed both nationally in Brazil (TANAJURA et al, 2011; GONÇALVES et al, 2010; ALMEIDA, 2008; ROCHA et al, 2008; RIBEIRO, 2005; ANGULO, 1996), and globally (SMITH and CROMLEY, 2012; JACKSON et al, 2012; BAPTISTA et al, 2011; STOCKDON et al, 2002; THIELER and DANFORTH, 1994, among others). Shoreline monitoring at higher temporal resolution is essential for mitigating the impacts of coastal erosion that has recently featured prominently in the Brazilian news. It is common to find coastal changes classified as long-term and short-term. Long-term may be related to changes in average sea level, sediment transport, wave energy, geological controls (contemporaries and antecedents) causing changes in its position over a period of hundred or thousands of years. Short-term, may occur on time scales of decades or smaller and are related to daily movement, monthly or seasonal changes in tidal currents, wave climate and episodic events (see e.g., HARLEY et al, 2011; GALGANO and DOUGLAS, 2000; GALGANO et al 1998; DEMAREST and LEATHERMAN, 1985)

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