<p><strong>ABSTRACT</strong></p><p>With the fast and highly growing demand for all possible ways of remote work as a result of COVID19 pandemic, new technologies using Satellite data were highly encouraged for multidisciplinary applications in different fields such as; agriculture, climate change, environment, coastal management, maritime, security and Blue Economy.</p><p>This work supports applying Satellite Derived Bathymetry (SDB) with the available low-cost multispectral satellite imagery applications, instruments and readily accessible data for different areas with only their benthic parameters, water characteristics and atmospheric conditions.&#160; The main goal of this work is to derive bathymetric data needed for different hydrographic applications, such as: nautical charting, coastal engineering, water quality monitoring, sediment movement monitoring and supporting both green carbon and marine data science. &#160;Also, this work proposes and assesses a SDB procedure that makes use of publicly-available multispectral satellite images (Sentinel2 MSI) and applies algorithms available in the SNAP software package for extracting bathymetry and supporting bathymetric layers against highly expensive traditional in-situ hydrographic surveys. The procedure was applied at SAFAGA harbor area, located south of Hurghada at (26&#176;44&#8242;N, 33&#176;56&#8242;E), on the Egyptian Red Sea coast.&#160; SAFAGA controls important maritime traffic line in Red Sea such as (Safaga &#8211; Deba, Saudi Arabia) maritime cruises. &#160;SAFAGA depths change between 6 m to 22m surrounded by many shoal batches and confined waters that largely affect maritime safety of navigation.&#160; Therefore, there is always a high demand for updated nautical charts which this work supports.&#160; The outcome of this work provides and fulfils those demands with bathymetric layers data for the approach channel and harbour usage bands electronic nautical chart of SAFAGA with reasonable accuracies. &#160;The coefficient of determination (R<sup>2</sup>) differs between 0.42 to 0.71 after applying water column correction by Lyzenga algorithm and deriving bathymetric data depending on reflectance /radiance of optical imagery collected by sentinel2 missions with in-situ depth data values relationship by Stumpf equation.&#160; The adopted approach proved to give&#160; highly reasonable results that could be used in nautical charts compilation. Similar methodologies could be applied to inland water bodies. &#160;This study is part of the MSc Thesis of the first author and is in the framework of a bilateral project between ASRT of Egypt and CNR of Italy which is still running.</p><p><strong>Keywords: Algorithm, Bathymetry, Sentinel 2, nautical charting, Safaga port, satellite imagery, water depth, Egypt.</strong></p>
Measuring and inferring the ice thickness distribution of four glaciers in the Tien Shan, Kyrgyzstan