MARCUSINPM

Evidence exists that sea spray-sourced ice nucleating particles (INPs) result from biological and biochemical processes in seawater and the sea surface microlayer, and represent a distinctly different and variable, but oftentimes much less effective INP population in comparison to long-range transported desert dust. Over the Southern Ocean, far from land sources, these INPs may dominate in the marine boundary layer. Thereby, marine INPs may affect cloud phase and lifetime in this region where pervasive supercooled and mixed‐phase boundary layer clouds appear underrepresented in climate models. This project supports daily aerosol filter collections that will be made during the Measurements of Aerosols, Radiation, and Clouds over the Southern Ocean (MARCUS). The second ARM Mobile Facility's (AMF2) deployment on the Aurora Australis, for subsequent processing to determine the temperature spectrum of the concentrations of INPs active via the immersion freezing mechanism across the temperature regime from 0 to -27°C. Additional analyses (thermal, chemical) will be used to discern the biogenic versus inorganic contributions to INP populations. Portions of frozen samples of aerosols in liquid will be archived for future analyses, such as genetic analyses of biological community diversity in aerosols. The INP measurements collected for the MARCUS cruises will supplement and complement other aerosol and remote sensing measurements from the AMF2 suite, as well as other measurements over the region that may occur as part of the international multiagency effort called the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES). The MARCUS INP collections may provide the only such data in the region south of 60 degrees south latitude during SOCRATES. The database developed will provide comparison and contrast versus other widespread marine INP samples collected during U.S. Department of Energy-funded (MAGIC and ACAPEX) and other studies. Measurements will assist development of parameterizations of marine INP sources for use in regional and global scale modeling of the impacts of marine boundary layer aerosols on clouds and climate.

Timeline

MAR Data Sources