A CMIP6-Based Frequency Analysis of the Extreme Precipitation Events in Virginia, USA

Abstract

In recent years, as a result of climate change and global warming, there have been noticeable increases in the number and severity of extreme climate events. The primary reason for these increases is the enhanced water holding capacity of the atmosphere caused by rising temperatures. Climate change, along with other factors such as changes in land use, has a major role in floods becoming more frequent and severe around the World. In this regard, it is important to investigate and model the effects of changes that will occur in the forthcoming years on extreme precipitation. In this study, the outputs of five new general circulation models (GCM) used to analyze future extreme precipitation events under two new socioeconomic scenarios (SSP2-4.5 and SSP5-8.5). The daily precipitation values of five stations in Virginia state,Unites States, measured between 1985 and 2014 were used to correct the biases in GCMs' outputs by using linear scaling method. Frequency analyzes were established on partial-duration series obtained by using two different methods known as annual maximums and peaks-over-threshold. The partial duration time series were fitted to appropriate distribution functions. Then, the intensity of extreme precipitation events with 2, 5, 10, 20, 50, 100, 500, and 1000 years return period was calculated for 1985-2014 (reference period), 2015-2040 (near future), 2041-2070 (med-term future), and 2071-2100 (late future) periods. The intensity of the extreme precipitation events was projected to decrease during the near future and increase significantly by the end of the century, according to the results of this study. The increase is more remarkable for SSP5-8.5 scenario in comparison to SSP2-4.5 scenario. These results highlight the importance of low-emission scenarios in reducing natural disasters.