Spatial Trend Analysis of Vegetation Dynamics and Their Responses to Climate Change on Black Sea Coasts, Romania From 2000 to 2021

Abstract

Based on the normalized difference vegetation index (NDVI) time series of moderate-resolution imaging spectroradiometer products, meteorological observations, and spatial trend analysis, the authors analyze how climate change and vegetation cover have changed in the Black Sea coasts over the past 22 years. Moreover, spatial correlation analysis was used to examine the correlation between climatic factors and NDVI as a proxy of vegetation productivity. With growth rates of 0.003, 0.5°C, and 5.5 mm per year, respectively, the inter-annual variation of NDVI, temperature, and precipitation revealed a noticeably growing trend. At the seasonal time scale, a similar trend was observed, which was statistically significant in some cases. The spatial-temporal trend of NDVI showed a greening trend in the inter-annual and seasonal time scales (except autumn). The greening trend in vegetation refers to the increase in vegetation productivity and density over time. The authors conclude that the most effective factor in the vegetation greening process is an increasing trend in temperature and precipitation.