The data set consists of yearly maps of the start of the vegetation active period in deciduous vegetation and coniferous forest. The start of vegetation active period in deciduous vegetation (Day of Year) is defined as the day when deciduous trees unfold new leaves in spring. It is also often referred to as the green-up or greening day. The data set was derived from time series of the Normalized Difference Water Index (NDWI) calculated from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations. The start of vegetation active period in coniferous forest (Day of Year) is defined as the day when coniferous trees start to photosynthesize in spring. The data set was derived from MODIS satellite observation of Fractional Snow Cover. The day when snow cover decreases during spring melt was used as a proxy indicator for the beginning of the start of the vegetation active period. The data set can be used of phenology analysis at regional and national scale and as input data for modelling. This SYKE’s dataset can be used according to open data license (CC BY 4.0)

Alueita, joilla lumi viipyi muuta ympäristöä pidempään tunnistettiin Sentinel 2 -satelliittikuvilta käyttäen Google Earth Engine Sentinel 2 satelliittikuva-arkistoa vuosilta 2018-2021. Kuvia verrattiin vaiheittain kahden viikon välein eri alueilta. Pikseli on tulkittu lumenviipymäksi, jos vuosien 2018-2020 satelliittikuvissa pikselin keskiarvo ylittää tietyn raja-arvon Normalized Difference Snow Index:ssä (NDSI). Aineisto on 10x10 m rasteri. Lisätietoja Ylä-Lapin kaukokartoitushankkeen loppuraportissa https://julkaisut.metsa.fi/julkaisu/yla-lapin-luonnon-kaukokartoitus-projektin-loppuraportti-osa-1-aineistot-ja-menetelmat/ Aineistoja on käytetty Ylä-Lapin biotooppitiedon päivitykseen. Aineistoja voi käyttää erilaissa selvityksissä ja ympäristöhallinnon tehtävien tukena. Aineisto kuuluu SYKEn avoimiin aineistoihin (CC BY 4.0) --- Northern Lapland: Snowbeds is produced by combining of satellite-based remote sensing and field observations. The data is a 10 x10 m raster. The dataset will be available in the next Habitats Directive reporting and in the assessment of threatened habitats as well as in other surveys, assessments and studies, and they can be used in the implementation of the EU Biodiversity Strategy. More information: https://www.metsa.fi/en/project/remote-sensing-northern-lapland/ This SYKE’s dataset can be used according to open data license (CC BY 4.0)