Hydroperiod Estimation from Satellite-based Water masks Using the Hydromap Module from the ECOPOTENTIAL Virtual Laboratory
Ioannis Manakos, Georgios Kordelas, Marios Bakratsas, Kalliroi Marini CERTH (GR); Javier Bustamante, David Aragonés, Ricardo Díaz-Delgado, EBD-CSIC (ES)
Hydroperiod is the length of time each location remains flooded throughout a year in seasonal wetlands. It is an important ecological parameter driving the growth and composition of vegetation communities, and the abundance and distribution of animals in wetlands. Monitoring the hydroperiod duration through time is thus of vital importance for wetland managers and relevant authorities in order to develop ecosystem services preservation activities.
Satellite data offer the opportunity to derive the extent of inland surface water with high frequency and accuracy, hence allowing for hydroperiod estimation by using time-series of satellite-based water masks. Within ECOPOTENTIAL, a specific tool for calculating hydroperiod, the Hydromap module, was developed by the CERTH (Centre for Research and Technology Hellas) team. This module generates the hydroperiod for a desired time period from series of satellite-based water masks by applying the following interpolation approach. For two dates separated by a number nof days, the occurrence of water is compared. If a pixel is inundated on both dates, then it is assumed inundated for the whole duration of the n-days. If a pixel is inundated on a single date, then it is assumed inundated for n/2 days. The total number of days of inundation per pixel in the hydroperiod map is determined by accumulating the water masks throughout the desired time period.
Hydromapinput includes: (i) a series of water masks, (ii) the list of dates water masks correspond to, and (iii) the starting and ending date defining the time period for which to estimate hydroperiod. The output is the hydroperiod map. Input water masks and resulting hydroperiod map are in GeoTIFF format.