Kasvukauden alku / Start of vegetation period

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)