Rainfall and Vegetation Growth in Wildfire Areas

Abstract

In recent years California has experienced wildfire seasons of increasing frequency and magnitude, especially in terms of wildfire burned areas. Here we investigate the precipitation and vegetation growth preceding each wildfire season for the years 2017, 2018, and 2019 to determine if antecedent rainfall leads to enhanced vegetation growth in wildfire burned areas in California. Precipitation data from the Global Precipitation Measurement (GPM) Mission and Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) data are examined to determine if antecedent rainfall and vegetation were normal, above, or below average, for the peak wet (December-Feb) and peak growth (March-May) periods preceding each wildfire season, as well as for the two previous wet and growth seasons. Then spatial correlations are done between precipitation and the vegetation indexes to determine the statistical significance of the relationships. The wildfire seasons of 2017, 2018, and 2019 were generally found to be preceded by above-average levels of precipitation and vegetation growth. Linear regression model results show high positive correlations between precipitation and vegetation, suggesting that antecedent rainfall fueled vegetation growth that might have caused a significant impact on wildfire burned areas. When only the correlations inside and within 10 km of wildfire burned areas are considered, our results show that most of the areas exhibited statistically significant positive correlations between rainfall and the vegetation indexes, especially with NDVI. Our results suggest that antecedent rainfall in California made wildfire burned areas more severe by enhancing vegetation growth that would later become available fuel. 

Results

Title Format Download Students Rainfall and Vegetation Growth in Wildfire Areas video Rainfall and Vegetation Growth in Wildfire Areas Elisabeth Grosvenor, Jenna Mann

 

Keywords:  California, drought, water, rain, plant, fire, CalFire, FRAP, NASA, MODIS, mean, anomoly, map, adaptability, responsiveness, Jose J Hernandez Ayala, RSCAP