The SACHI (Sentinel-1/2 derived Arctic Coastal Human Impact) V1 dataset was developed as part of the HORIZON2020 project Nunataryuk by b.geos (www.bgeos.com). V1 covered a 100km buffer from the Arctic Coast (land area), for areas with permafrost near the coast. V2 has been prepared as part of the ESA project EO4PAC. It covers additional selected areas extending the coverage to the south.It is based on Sentinel-1 and Sentinel-2 data from 2016-2020 using the algorithms described in Bartsch et al. (2020). V1 is a supplement to Bartsch et al. (2023) and V2 to Tanguy et al. (2024). V2 consists of two shape files. 1) SACHI_v2.shp - all identified objects with infrastructure/impact classes and auxiliary information2) SACHI_v2_granules_acquisition_dates - processed Sentinel-2 granule extent polygons with dates of all used input data Dataset reference: see Zenodo 'Sentinel-1/2 derived Arctic Coastal Human Impact dataset (SACHI) v2' (zenodo.org) Description of fields in SACHI_v2.shp: class: SACHI class value. 11=linear transport infrastructure (asphalt), 12=linear transport infrastructure (gravel), 13=linear transport infrastructure (undefined),20=buildings (and other constructions such as bridges), 30=other impacted area (includes gravel pads, mining sites), 40=airstrip, 50=reservoir or other water body impacted by human activities Description of fields in SACHI_v2_granules_acquisition_dates.shp: S2_date1 to S2_date3 - dates of individual Sentinel-2 images used for averagingS1_winter - year(s) of Sentinel-1 images used for averaging (months December and/or January)

Further support was received by ESA EO4PAC for v2, by ESA CCI+ Permafrost, HGF AI-CORE, and NSF Permafrost DiscoveryGateway for v1. The processing scheme was developed on a highly performant virtual machine (VM) provided by the Copernicus Research and User Support (RUS). Results are based on modified Copernicus data from 2016 to 2020.