The Global offshore wind turbine (OWT) dataset derived from satellite imagery provides the spatiotemporal distribution of wind turbines from 2015 to 2019 at 10m resolution. This dataset has the potential to further elucidate the impact of OWTs on coastal ecosystems, support biodiversity conservation and environmental impact assessments, and help generate sustainable development strategies for offshore wind energy.

This repo contains code that walks through key steps to extract the global offshore wind turbine dataset in Google Earth Engine and extract the completion time of each wind turbine in MATLAB. The code used for extracting offshore wind turbine is shown in the file of "code_OWFextraction.js", including the key steps of images collection, removal of floating or temporarily mobile objects, extraction of high-backscatter objects using ‘half-min-max threshold’, morphological operation, removal of large and minute objects. To run the code for extracting the offshore wind turbine, an account on Google Earth Engine is necessary. Note that while the code for OWTs extraction is openly available, the underlying datasets ('assets' in Google Earth Engine) are not all (yet) publicly available. Assets, such as the analysed grids derived from exclusive economic zone (EEZ), can be shared depending on the request, however there is no guarantee that we will host all original input assets for long, since they might change as improved data becomes available.

The code used for extracting installed time of each wind turbine, i.e. Mann-Kendall (MK) test algorithm is shown in the file of “code_MKtest.m”. The detailed calculation process of this algorithm can be found in Hamed 2008. The function used in “code_MKtest.m”, including “mk.m”, “mkabrpt.m” and “smk.m”. The Microsoft Excel file “TimeSeriesBS_2015to2019.xlsx” contain the time series backscattering coefficient for each turbine, it is obtained from GEE, and as an input data of the MK test algorithm. To use the MATLAB code, you need reset the location information of the input file that have the backscattering coefficient information.