Speaker
Description
The Africa Regional Data Cube (ARDC) is a new tool that aims to provide the latest earth observation and satellite technology to African countries, currently focusing on Kenya, Senegal, Sierra Leone, Ghana, and Tanzania, to address the sustainable development goals like food security as well as issues related to agriculture, deforestation, water access, etc. The open data cube (ODC) was developed by the Committee on Earth Observation Satellites (CEOS) in partnership with the Group on Earth Observations, Amazon Web Services, Strathmore University in Kenya, Office of the Deputy President - Kenya, and the Global Partnership for Sustainable Development Data.
Recent efforts have been undertaken to also include synthetic aperture radar (SAR) data and specifically Sentinel-1 CSAR in the form of “easy to use” analysis ready data (ARD) sets with the intention to make SAR data accessible to a broader community and explore more its potential for environmental monitoring in Africa.
As a first country case, the full Sentinel-1 interferometric wide swath mode level-1 GRD (ground range detected) data over Ghana has been processed into higher level ARD covering the period March 2015 to the present. The ARD consist in a time series of dual-polarization (VV and VH) monthly-averaged slope-corrected gamma naught (γ0) backscatter mosaics. Additionally, first order yearly statistical parameters are also extracted during the processing.
In this study, we will present the full set of ARD time series over Ghana that will be made available through the ARDC and show how they can be used by local stakeholders for environment monitoring. We will specifically focus on the monitoring of “galamsey”, which is illegal small-scale gold mining and a main threat to the environment in Ghana.
The 3.5 year time series show clearly the resultant large scale environmental damage of forest loss resulting from the illegal mining. The results confirm earlier studies from 2017 done with optical Sentinel-2 data that have been validated with ground truth observation. The recent Sentinel-1 mosaics are also compared to historic observation based on L-band SAR from ALOS PALSAR from 2007/2008, showing the extent over a whole decade. Furthermore, we investigate the potential to use such Sentinel-1 ARD for near-real time detection of new areas of mining activities in the future. Other environment applications of Sentinel-1 ARD will also be discussed.
Summary
We will present advanced Sentinel-1 analysis ready data for Ghana and their application for environment monitoring with focus on monitoring of illegal mining.
