Landsat 8 OLI satellite data for mapping of the <i>Posidonia oceanica</i> and benthic habitats of coastal ecosystems

Abstract

&lt;p&gt;This is the accepted manuscript of the paper &quot;Landsat 8 OLI satellite data for mapping of the Posidonia&lt;br&gt; oceanica and benthic habitats of coastal ecosystems&quot;, published as final paper in &quot;International Journal of Remote Sensing&quot; Volume 40, 2019 - Issue 4&lt;/p&gt; &lt;p&gt;&lt;a href="https://doi.org/10.1080/01431161.2018.1528020"&gt;https://doi.org/10.1080/01431161.2018.1528020&lt;/a&gt;&lt;/p&gt; &lt;p&gt;The benthic seabeds and seagrass ecosystems, in particular the vulnerable &lt;em&gt;Posidonia oceanica&lt;/em&gt; (PO), are increasingly threatened by climate change and other anthropogenic pressures. Along the 8000 km coastline of Italy, they are often poorly mapped and&lt;br&gt; monitored to properly evaluate their health status. Thus to support these monitoring needs, the improved capabilities of the&lt;br&gt; Landsat 8 Operational Land Imager (OLI) Earth Observation (EO) satellite system were tested for PO mapping by coupling its atmospherically corrected multispectral data with near-synchronous sea truth information. Two different approaches for the necessary atmospheric correction were exploited focusing on the Aerosol Optical Depth (AOD) and adjacency noise effects, which typically occur at land&ndash;sea interfaces. The general achievements demonstrated the effectiveness of High Resolution (HR) spectral&lt;br&gt; responses captured by OLI sensor, for monitoring seagrass and sea beds in the optically complex Tyrrhenian shallow waters, with&lt;br&gt; performance level dependent on the type of applied atmospheric pre-processing. The distribution of the PO leaf area index (LAI) on&lt;br&gt; different substrates has been most effectively modelled using on purpose developed spectral indices. They were based on the&lt;br&gt; coastal and blue-green OLI bands, atmospherically corrected using a recently introduced method for AOD retrieval, based on the Short Wave Infrared (SWIR) reflectance. The alternative correction method including a less effective AOD assessment but the&lt;br&gt; removal of adjacency effects has proven its efficacy for improving the thematic discriminability of the seabed types characterized by different PO cover&ndash;substrate combinations.&lt;/p&gt;