The potential influence of marine biological activity on ice nuclei concentrations over the Southern Ocean Susannah Burrows1,2

with contributions from: C. Hoose3, U. Pöschl2, M. G. Lawrence2,4

1 – Pacific Northwest National Laboratory2 – Max Planck Institute for Chemistry3 – Karlsruhe Institute of Technology4 – Institute for Advanced Sustainability Studies

Burrows, S. M., Hoose, C., Pöschl, U., and Lawrence, M. G.: Ice nuclei in marine air: biogenic particles or dust?, Atmos. Chem. Phys., 13, 245-267, doi:10.5194/acp-13-245-2013, 2013.

2

Do biological / biogenic particles matter for ice nuclei (IN) populations?

Globally, the most-important and best-studied ice nuclei are dust (and soot), BUT:

Some biological / biogenic particles are more efficient IN than dust, particularly at warmer temperatures.Might induce freezing earlier, changing cloud development

Emerging picture: a possible role for biological / biogenic particles as IN under certain conditions:

Possible role of organic / biological material in enhancing IN activity of dust (Schnell and Vali, 1972; Pratt et al., 2009; Conen et al., 2011, others)

Pristine, biologically active continental environments in absence of dust (“green ocean”) (Prenni et al., 2009)

Warm, low-altitude mixed-phase clouds (Spracklen and Heald, 2013)

Marine environments? (Bigg, 1973; Schnell and Vali, 1976; Burrows et al., ACP, 2013, Knopf et al., 2012, others)

Measurements of IN concentrations in marine air

IN concentrations compared to Chl-a distribution

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In situ data: Bigg, 1973; Chlorophyll: MODIS climatology

Chl-a in µg m-3

B73 IN counts(different color scale)

Schnell and Vali (1976): Possible marine biological source of IN?

Burrows et al., ACP, 2013

Marine biological IN estimate

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Satellite data: proxies for marine biological activity

(POC, Chl-a)

Model parameterization:

Sea spray emissions

Intermediate result from simulations:

Particulate organic matter in sea spray

In situ data: IN concentration in marine plankton

bloom

Result: IN estimate in sea spray

Comparison with filter measurements and estimated

dust IN concentrations

Satellite: POC

Burrows et al., ACP, 2013

Comparison at -15°C (from B73)

Simulated POM concentrations

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Burrows et al. (2013)

Vignati et al. (2010)

Particulate organic matter (POM), μg m-3

Burrows et al., ACP, 2013

Comparison of proposed marine biological IN distribution with estimated dust IN distribution

Burrows et al., ACP, 2013

Upper bound:BIO-IN ∙ 10

{or dust IN ∕ 10 }

Marine biological IN: percent contribution to total simulated IN(total = dust + marine biological)

- compared at -15°C- in MBL- annual mean

8 Burrows et al., ACP, 2013

UPPER

BEST

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Moving sea spray chemistry forwardEmpirical parameterizations semi-mechanistic

Chl-a (correlated) surfactants (causal)

Extrapolate from blooms Account for different chemistry in gyres

Burrows et al., ACPD, 2014

Gantt et al., 2011Burrows et al., ACPD, 2014