EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Challenges in constructing a source function for high-temperature marine INPs

Isabelle Steinke1, Paul DeMott2, Grant Deane3, Tom Hill2, Matthew Maltrud4, Aishwarya Raman1, and Susannah M. Burrows1
Isabelle Steinke et al.
  • 1Atmospheric Sciences & Global Change, Pacific Northwest National Laboratory, Richland, Washington, USA
  • 2Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, USA
  • 3Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California, USA
  • 4Climate Ocean Sea Ice Modeling, Los Alamos National Laboratory, Los Alamos, New Mexico, USA

Sea spray emissions are an important source for ice nucleating particles (INPs) over remote ocean regions. Over the past years, our understanding of marine organic surfactants acting as INPs has advanced a lot. However, there are still significant knowledge gaps regarding the role of larger marine biogenic particles (e.g. polymers, diatom fragments, protists and bacteria) which are potentially the drivers of episodically observed high INP concentrations.
In this study, we use a combination of ARM (Atmospheric Radiation Measurement) observations and output from E3SM (Energy Exascale Earth System Model) simulation runs to investigate the impact of larger marine biogenic particles acting as INPs. We use heterotrophic bacteria and nanogels (polymeric particles) as two hypothesized classes of marine INPs which can get transported across the sea-air interface. Based on the offline-calculated concentrations of these ice nucleating entities in the ocean surface layer, we conduct sensitivity studies to estimate INP concentration ranges, relying on current knowledge of enrichment factors and ice nucleation activities (e.g., ns values from McCluskey et al. (2018)). In comparison to observations of episodic high INP concentrations, our estimated concentrations are consistently lower. However, one of the main conclusions of our study is that large uncertainties regarding the links between ocean biology, organic matter in sea spray and ice nucleation properties, remain. Therefore, comprehensive observational datasets, including sea spray size distributions, aerosol and INP compositions, and ice nucleation efficiencies of individual marine species, are needed. 

How to cite: Steinke, I., DeMott, P., Deane, G., Hill, T., Maltrud, M., Raman, A., and Burrows, S. M.: Challenges in constructing a source function for high-temperature marine INPs, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10410,, 2021.