Measured and Predicted Ice Nucleating Particle Concentrations during Saharan Dust Events at the Cyprus Atmospheric Observatory

Ice nucleating particles (INPs), a very minor fraction of the atmospheric aerosol, initiate primary ice formation in tropospheric clouds and thereby affect the weather and climate systems. Both laboratory experiments and field observations are needed in order to accurately formulate and predict the atmospheric INP concentration in weather and climate models. Here we focus on mineral dust aerosol, originating from the major desert areas in Northern Africa and Central Asia, which are known to contribute a major fraction to the atmospheric INP abundance. In particular during spring, frequent Saharan and Middle East dust outbreak events occur over the Eastern Mediterranean area.

During the four-week INUIT-BACCHUS-ACTRIS campaign in April 2016, several in situ and sampling INP measurement methods were deployed at the Cyprus Atmospheric Observatory (CAO) in order to measure the abundance and variability of atmospheric INP concentrations active in a wide temperature and humidity range. Here we present the results from periods which were influenced by dust from the Sahara. The INP measurements will also be compared with predictions from parameterizations based on aerosol particle number and surface area. During the Cyprus field campaign, the aerosol number concentration and size distribution were measured with condensation and optical particle counters.