Global Cloud Particle Measurements on Commercial Aircraft as part of In-Service Aircraft for a Global Observing System (IAGOS)

In-Service Aircraft for a Global Observing System (IAGOS) is a European research infrastructure with the aim of making global observations of many atmospheric properties with the use of instruments installed on commercial aircraft. Here we present measurements from 8 Backscatter Cloud Probes (BCPs) on commercial aircraft of cloud particles over the size range 5-75 µm from 1000s of flights across the globe between 2011 and 2018. From the measurements of particle size and concentration we are able to derive cloud properties such as the Liquid/Ice Water Content (LWC/IWC), the Effective Diameter (ED) and Median Volume Diameter (MVD).

With the diversity of aircraft carriers, including Air France, Lufthansa and China Airlines we have been able to examine the variability of cloud particles on a global scale, finding changes in properties such as cloud frequency, number of particles and cloud altitude that are related to geographical location and season. Primarily our goal is to report number concentrations of cloud particles detected by the BCP at cruise altitude representing global cirrus properties, but we also extend this work to include seasonally separated profiles of cloud particles in different regions such as South East Asia that are made as aircraft profile into and out of different airports, finding strong evidence for significant changes in particle concentrations driven by season.