Active thermokarst regions contain rich sources of ice nucleating particles

• Main Authors: Barry, Kevin R., Hill, Thomas C. J., Nieto-Caballero, Marina, Douglas, Thomas A., Kreidenweis, Sonia M., DeMott, Paul J., Creamean, Jessie M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2023
• Subjects: article; Verlagsveröffentlichung; Arctic; Ice; permafrost; Thermokarst; Tundra; wedge*; Alaska
• Online Access: https://doi.org/10.5194/egusphere-2023-1208; https://noa.gwlb.de/receive/cop_mods_00067450; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00065907/egusphere-2023-1208.pdf; https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1208/egusphere-2023-1208.pdf

Rapid Arctic climate warming, amplified relative to lower latitude regions, has led to permafrost thaw and associated thermokarst processes. Recent work has shown permafrost is a rich source of ice nucleating particles (INPs) that can initiate ice formation in supercooled liquid clouds. Since the phase of Arctic clouds strongly affects the surface energy budget, especially over ice-laden surfaces, characterizing INP sources in this region is critical. For the first time, we provide a large- scale survey of potential INP sources in tundra terrain where thermokarst processes are active and relate to INPs in the air. Permafrost, seasonally thawed active layer, ice wedge, vegetation, water, and aerosol samples were collected near Utqiaġvik, Alaska in late summer and analyzed for their INP contents. Permafrost was confirmed as a rich source of INPs that was enhanced near the coast. The aerosol likely contained a mixture of known and unsurveyed INP types that were inferred as biological. Arctic water bodies were shown to be important links of sources to the atmosphere in thermokarst regions. Therefore, a positive relationship found with total organic carbon gives a mechanism for future parameterization as permafrost continues to thaw and drive regional landscape shifts.