Ice-nucleating particle concentrations of the past: insights from a 600-year-old Greenland ice core ...

• Main Authors: Schrod, Jann, Kleinhenz, Dominik, Hörhold, Maria, Erhardt, Tobias, Richter, Sarah, Wilhelms, Frank, Fischer, Hubertus, Ebert, Martin, Twarloh, Birthe, Della Lunga, Damiano, Jensen, Camilla Marie, Curtius, Joachim, Bingemer, Heinz G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: University of Bern 2020
• Subjects: Greenland; Greenland ice core; ice core
• Online Access: https://dx.doi.org/10.7892/boris.147785; https://boris-portal.unibe.ch/handle/20.500.12422/45087

Ice-nucleating particles (INPs) affect the microphysics in cloud and precipitation processes. Hence, they modulate the radiative properties of clouds. However, atmospheric INP concentrations of the past are basically unknown. Here, we present INP measurements from an ice core in Greenland, which dates back to the year 1370. In total 135 samples were analyzed with the FRIDGE droplet freezing assay in the temperature range from -14 to -35 °C. The sampling frequency was set to 1 in 10 years from 1370 to 1960. From 1960 to 1990 the frequency was increased to one sample per year. Additionally, a few special events were probed, including volcanic episodes. The typical time coverage of a sample was on the order of a few months. Historical atmospheric INP concentrations were estimated with a conversion factor, which depends on the snow accumulation rate of the ice core, particle dry deposition velocity, and wet scavenging ratio. Typical atmospheric INP concentrations were on the order of 0.1 L-1 at -25 °C. The INP ...