Visualizing Extreme Precipitation for Climate Storytelling

Precipitation can have adverse effects in the climate ecosystem. Too much can impose concerns such as flooding and landslides, resulting in damaged property, agricultural losses, and loss of life. Too little, and drought becomes an issue, inducing wildfires, poor air quality, and health degradation. The contiguous United States has experienced an increase in precipitation since 1900, and much of this has occurred in the most recent decades (Melillo et al. 2014). By the end of the 21st Century, it is expected that more winter and spring precipitation will occur over the northern portion of the U.S., and less in the southwest. While much work has been performed on historical and projected analysis of heavy precipitation, few interactive visualizations exist for end users to better understand local impacts.

The goal of this project is to create a visualization tool that easily demonstrates how precipitation extremes have changed and might change in the future. The Global Historical Climatology Network-Daily dataset (GHCN-D; Menne et al. 2012) was used to calculate a historical record of extreme precipitation variables at locations in the United States. Among these variables calculated are annual accumulation percentiles, annual 1-day and 5-day maximum daily precipitation, and annual consecutive wet and dry days. Station values are validated with nearby gridded observations provided by Livneh et al (2013), and then projected out to the year 2100 using a 29 member ensemble of Localized Constructed Analogs (LOCA; Pierce et al. 2014). The data are calculated and written into a csv file which is then uploaded into ArcOnline and visualized in a manner that helps tell a story to the user community.