PINEair - A new instrument for aircraft-based in situ measurements of ice nucleating particles at cirrus formation conditions

点击翻译按钮获取中文摘要

High-altitude cirrus clouds are formed in the upper troposphere at temperatures below about -40°C. They consist of ice crystals, which have both a cooling and a heating contribution to the Earth’s climate. Which of the two processes dominates depends, among other factors, on the number concentration and size of the cirrus cloud ice crystals. This in turn depends on the abundance and type of so-called ice nucleating particles (INPs) in the atmosphere. INPs are a very minor fraction of atmospheric aerosol particles, which originate from a large number of different sources, and therefore exhibit a large variety of sizes, shapes and chemical composition. So far, no aircraft-based instrument exists to directly measure the atmospheric abundance of INPs at low temperatures. As part of this project, we suggest to build such an instrument for the first time and to certify it for measurements onboard the HALO research aircraft. This new and innovative instrument called PINEair (Portable Ice Nucleation Experiment – aircraft version) basically works like a cloud expansion chamber, similar to the AIDA cloud chamber of the Karlsruhe Institute of Technology (KIT). The compact and fully automated instrument will allow to measure for the first time upper tropospheric INP concentrations with high sensitivity and time resolution. The resulting data set will contribute to a better understanding of the formation of cirrus clouds, and to better quantify their role in the Earth’s climate system.