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Title: Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

Abstract

In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux atmore » the surface by 2 W m-2 in the pan-Arctic under the present-day climate.« less

Authors:
 [1];  [2];  [3]
  1. Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Now at Department of Earth System Science, University of California, Irvine California USA
  2. Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA
  3. Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340876
Report Number(s):
PNNL-SA-115198
Journal ID: ISSN 2169-897X
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Geophysical Research: Atmospheres; Journal Volume: 121; Journal Issue: 18
Country of Publication:
United States
Language:
English

Citation Formats

Xu, Li, Russell, Lynn M., and Burrows, Susannah M. Potential sea salt aerosol sources from frost flowers in the pan-Arctic region. United States: N. p., 2016. Web. doi:10.1002/2015JD024713.
Xu, Li, Russell, Lynn M., & Burrows, Susannah M. Potential sea salt aerosol sources from frost flowers in the pan-Arctic region. United States. doi:10.1002/2015JD024713.
Xu, Li, Russell, Lynn M., and Burrows, Susannah M. Fri . "Potential sea salt aerosol sources from frost flowers in the pan-Arctic region". United States. doi:10.1002/2015JD024713.
@article{osti_1340876,
title = {Potential sea salt aerosol sources from frost flowers in the pan-Arctic region},
author = {Xu, Li and Russell, Lynn M. and Burrows, Susannah M.},
abstractNote = {In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m-2 in the pan-Arctic under the present-day climate.},
doi = {10.1002/2015JD024713},
journal = {Journal of Geophysical Research: Atmospheres},
number = 18,
volume = 121,
place = {United States},
year = {Fri Sep 23 00:00:00 EDT 2016},
month = {Fri Sep 23 00:00:00 EDT 2016}
}
  • Description of the Project: This project has improved the aerosol formulation in a global climate model by using innovative new field and laboratory observations to develop and implement a novel wind-driven sea ice aerosol flux parameterization. This work fills a critical gap in the understanding of clouds, aerosol, and radiation in polar regions by addressing one of the largest missing particle sources in aerosol-climate modeling. Recent measurements of Arctic organic and inorganic aerosol indicate that the largest source of natural aerosol during the Arctic winter is emitted from crystal structures, known as frost flowers, formed on a newly frozen seamore » ice surface [Shaw et al., 2010]. We have implemented the new parameterization in an updated climate model making it the first capable of investigating how polar natural aerosol-cloud indirect effects relate to this important and previously unrecognized sea ice source. The parameterization is constrained by Arctic ARM in situ cloud and radiation data. The modified climate model has been used to quantify the potential pan-Arctic radiative forcing and aerosol indirect effects due to this missing source. This research supported the work of one postdoc (Li Xu) for two years and contributed to the training and research of an undergraduate student. This research allowed us to establish a collaboration between SIO and PNNL in order to contribute the frost flower parameterization to the new ACME model. One peer-reviewed publications has already resulted from this work, and a manuscript for a second publication has been completed. Additional publications from the PNNL collaboration are expected to follow.« less
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