Applicability of remote sensing techniques to the study of aeolian systems in coastal areas

Remote sensing techniques have been applied extensively during the last few years for a wide range of purposes. The availability of high-quality data and new affordable software has increased the number of people interested in these technologies. In the field of Geomorphology, video systems and imagery have been applied with success to the monitoring and management of coastal stability problems on sandy coastlines, measurement of shoreline evolution and response to storms, seasonal cycles and anthropogenic interventions like beach/shoreface nourishment and dredging. However, coastal dune systems have not been commonly included in remote sensing studies, and the absence of high-quality data of foredune dynamics over long periods keeps holistic approaches away from numerical modeling. The controls on dune growth over the longer temporal scale are complex, and there are a number of issues associated with the different temporal/spatial scales of the factors affecting it. The work presented here explores the applicability of remote sensing techniques to the study of aeolian processes at the coast, and its potential in establishing links between factors affecting sediment input from the beach to the dune at different temporal scales. The monitoring station is located at Greenwich Dunes, PEI National Park, PEI (Canada). We have deployed three cannon digital cameras on a 6m mast on top of an 8m foredune crest, each taking hourly exposures during daylight hours. A 2D sonic anemometer mounted at the top of the mast provides continuous record of wind speed and direction. Sediment transport and deposition/erosion processes are measured using a set of Sabatech saltation probes and pins permanently deployed at the backshore area and at the base of the foredune. Through a combination of ArcMap 9.2 and PCI Geomatica tools the pictures are analyzed following a procedure of several steps, such as image rectification or camera calibration for measuring surface moisture content on the beach surface. The result is a large database (constructed using Oracle software) including time series of wind speed and direction, transport processes, moisture maps, vegetation cover, shoreline position, fetch distances, and other factors involved in the aeolian system at Greenwich. This database is a primary source of information where the dynamics of the aeolian system can be queried in an easy way, and the basis for the subsequent modeling. The monitoring of the magnitude, frequency, and timing of events that deliver sediment to the dune will allow us to understand the relative importance of different variables and events. The overall goal is to assess the applicability of remote sensing techniques in measuring beach/dune aeolian processes, and to build a dynamic stochastic model that improves our predictions of dune growth and evolution to better assist management projects.