Assessing climate impacts on urban forest changes using time series satellite data

摘要

Understanding how urban forest land cover responds to climate change requires knowledge of land-surface interaction processes, which control the degree to which interannual variability and mean trends in climatic variables affect the surface energy budget and by this forest vegetation. Urban forest represents unique areas for the detection of climatic change and the assessment of climate-related impacts. Effects of climate extremes and anthropogenic changes on urban/peri urban forest systems in Romania can have both short-term and long-term implications for standing biomass, tree health and species composition. This paper used time series of normalized difference of vegetation index (NDVI) and enhanced vegetation index (EVI) as well as leaf area index (LAI) as a measurement indicators of forest dynamics at metropolitan scale in order to assess impacts of climate changes on forest ecosystem phenology in metropolitan area of Bucharest. Use of satellite remote sensing to monitor the forest changes due to climatic stressors is an excellent example of the value of multispectral, multiresolution and multitemporal observations. Fusion technique was applied to time series satellite imagery data (Landsat TM/ETM/OLI, Sentinel 2 and MODIS Terra/Aqua satellite data) for urban/periurban forest ecosystem of Bucharest metropolitan area in Romania over 2000-2019 period. Also, this paper addresses a number of issues related to changes in land surface temperature (LST), and analyses correlations between NDVI/EVI time series and climatic variables under different scenarios for summer heat waves, windstorms and heavy precipitation.