Absorbing Aerosol Index from GOME-2 A & B shows plumes from extreme wildfires in Chile


by Maurits Kooreman (KNMI) 29 January 2017

Forest fires occur frequently in Chile's hot summers, but persisting droughts and record high temperatures now cause ideal conditions for devastating wildfires. On January 20th Chile declares the state of emergency as wildfires threaten to destroy villages and vineyards. By January 30th the fires have taken 11 lives, burned over 1000 homes and wiped an entire town off the map (source: Reuters).

After raging on for multiple weeks, the persistent fires produced a large scale plume which stretches for thousands of kilometers into the Pacific Ocean. As fires produce soot as well as water vapor, the plumes consist of a mix of the two. Possibly, the smoke particles in the plume are acting as condensation nuclei for the water vapor to condense on, and produce a mix of soot and water droplets. The colorful overlay in Figure 1 shows Absorbing Aerosol Index (AAI), distinguishing the soot particles from the water vapor plume. The AAI is retrieved from the GOME-2 A&B instruments and plotted over a visible spectrum image from the MODIS spectrometer aboard the Terra satellite. The red values indicate an AAI of over 3, where a value of 2 is already considered as indicating significant aerosol presence.