Aerosol concentration data from the G-1 ultrafine condensation particle counter are shown for an approximately three-hour flight on December 8, 2018, near Córdoba, Argentina, during the CACTI campaign. Image is from Krista Gaustad, Pacific Northwest National Laboratory. From 2010 until its final science mission in 2018, the Gulfstream-159 (G-1) aircraft served as the Atmospheric Radiation…