AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Understanding and Modeling Sources of Ice Nucleating Particles in Earth System Models
SUSANNAH BURROWS, Christina McCluskey, Xiaohong Liu, Paul DeMott, Pacific Northwest National Laboratory
Abstract Number: 520 Working Group: Aerosols, Clouds and Climate
Abstract Sea-spray aerosol is enriched in marine organic matter originating from phytoplankton. Although the complex biology and chemistry controlling the emitted aerosol is not yet fully understood, sea spray organic matter may alter the magnitude of sea spray emissions, and enable sea spray to act as a source of ice nucleating particles (INPs). OCEANFILMS (Burrows et al., 2014) is an approach to modelling the relationship between ocean biogeochemistry and emitted sea spray aerosol chemistry for Earth System Models, which has recently been implemented in version 1 of the Energy Exascale Earth System Model (E3SMv1), developed by the U.S. Department of Energy (Burrows et al., ACPD, in revision). The conceptual approach of OCEANFILMS will be described and impacts on simulated aerosols and clouds will be highlighted.
In a related study, we have evaluated the potential of a current global Earth System Model to skillfully simulate observed boundary-layer INP concentrations at coastal and marine locations (McCluskey et al., submitted). The OCEANFILMS parameterization was implemented into version 1 of the Community Earth System Model (CESM1), and a recently-developed active site density parameterization for marine INP (McCluskey et al., 2018) was applied to calculate the INP concentrations from simulated sea spray aerosol. Simulated dust INP were parameterized as well (DeMott et al., 2015). Nudging of atmospheric winds was used to match observed meteorology during two recent field campaigns – a coastal campaign at Mace Head, Ireland, and a shipboard campaign in the Southern Ocean. The resulting INP concentrations were compared with observed INP concentrations. Agreement with observations was improved by including sea spray INPs, and sea spray aerosol was a dominant contributor to the INP population at cloud-relevant altitudes. This study demonstrates the need to account for INPs associated with sea spray aerosol and their subsequent influence on cloud phase transitions.