Obtaining reproducible reports on satellite hotspot data during a wildfire disaster

NATALIA SOLEDAD MORANDEIRA

Zurich

Conferencia; useR! 2021 - The R conference; 2021

The R Foundation

Wildfires can be monitored and analyzed using thermal hotspots records derived from satellite data. In 2020, the Paraná River floodplain (Argentina) suffered from a severe drought, and thousands of hotspots ?associated with active fires? were reported by the Fire Information for Resource Management System (FIRMS-NASA). FIRMS-NASA products are provided in spatial objects (shapefiles), including recent and archive records from several sensors (VIIRS and MODIS). I aimed to handle these data, analyze the number of hotspots during 2020, and compare the disaster with previous years´ situation. Using sf, tidyverse, janitor, stringr, spdplyr, ggplot2 and RMarkDown, I imported and pre-processed the spatial objects, generated plots, and obtained reproducible reports. I used R to handle satellite data, monitor the number of active fires, and detect which wetland areas were being affected: this allowed me to quickly respond to peers and journalists about how the wildfires were evolving. As a case study, I summarize the 2020 outputs for my study area, the Paraná River Delta (19,300 km2). A total of 39,821 VIIRS thermal hotspots were detected, with August (winter in the Southern Hemisphere) accounting for 39.8% of the whole year?s hotspots. While VIIRS data (resolution: 375 m) is available from 2012, MODIS data is available from 2001. However, MODIS resolution is 1 km, so fewer hotspots are reported and each hotspot corresponds to a greater area. The cumulative MODIS hotspots recorded during 2020 were 8,673, the highest number of hotspots of the last 11 years. However, MODIS hotspots detected in 2020 were 62.9% of those recorded during 2008. Plots were obtained in English and Spanish versions, showing daily and cumulative hotspots, monthly summaries, and a comparison with hotspots detected in previous years. My workflow can be used to analyze thermal hotspot data in any other interest area.