Project objective: We want to use PolSAR combined with intermittent drone campaigns to monitor erosion, grass phenology and plant stress in marshes.
Deliverables: In this project, we will set up a series of methodologies that utilises images acquired from space and will be able to provide weekly update of coastal habitat conditions to local conservation authorities. We are also interested in monitoring the following events: erosion due to storms, biophysical parameters of grasses (e.g. biomass), phenology (e.g. length of the vegetative stage) and how all these varied in the last decade. An expected output of this activity will be the capability to derive accurate erosion maps.
Novelty: PolSAR is a cutting edge technology and is very useful to retrieve biophysical parameters of vegetation [ESA-PolSAR]. However, this technology has never being used for marshes and coastal grasslands. The research work carried out in this project has the potential to revolutionise the sector and allow surveying coastal areas with an unprecedented repetition time.
Data (satellite): Archive PolSAR data are already available. Future acquisitions will be carried out synchronised to fieldwork. The datasets used will include the following satellite missions: ALOS-1 and ALOS-2 (Japanese Space Agency); RADARSAT-2 (Canadian Space Agency); COSMO-SkyMED (Italian Space Agency); Sentinel-1 (European Space Agency).
Data (drone): Beside radar data we will collect drone aerial photography in the Solway Firth and Skinflats. Two drones will be available: DJI Phantom 4 and DJI Mavic. We will also collect camera pictures of the vegetated areas at ground level.
Algorithm development: In this project we will develop algorithms that exploit weekly available PolSAR images combined with sporadic very high resolution drone images to improve management practices of coastal areas.
1) We will monitor changes, such as erosion or plant phenology, by applying change detectors. One of the methodologies will be based on the use of optimisations of polarimetric data [Marino et al 2014]. Figure 1 shows an example of the algorithm output applied to ALOS-1 data over Flookbourg in 2007 (near Maracombe bay, UK). This activity will allow to derive accurate erosion maps.
2) We will use scattering models to retrieve biophysical parameters of marshes and grasslands. The model will probably be semi-empirical and it will use some background physical model to decompose the received radar echo into a ground and a vegetation components. We will start from some simpler vegetation model as in Attema at al (1979) and then proceed to design a better model especially tailored for grasslands in tidal areas. One output will be the biomass of grass. The expected output is the capability to derive grass information as biomass, height or density.
3) Analysis of time series. This will allow to evaluate trends in biophysical parameters of grasses and identifying erosion. This information will be used to assess the changes that the Solway Firth and the Skinflats suffered in the last decades and try to predict the future of coastal ecosystems. One output will be the identification of changes in phenological stages.
Fieldwork: The Solway Firth and Skinflats will be periodically surveyed. We expect on average one fieldwork a month. During these visits we will carry out drone surveys when these are not disturbing wildlife (e.g. arrival of barnacle geese in winter). Drone data will be used to have a qualitative overall evaluation of the plant phenology and a quantitative assessment of erosion. Additionally, we will use photographs to collect plant information and to identify and validate erosion.
End Users: this project has strong links with end users including the Solway Firth Partnership, Natural Scotland and RSPB Scotland. We will be in frequent contact with our partners. We will take advantage of their local experience to tailor methodologies in order to retrieve the most usefulness biophysical parameters for management and protection of marshes. We will freely distribute our methodologies to partner and the general public, with the aim of producing some tangible change in practices. We will be involved in outreach events in the Solway Firth