Investigating Organic Aerosol Loading in the Remote Marine Environment
1 / 9

Investigating Organic Aerosol Loading in the Remote Marine Environment - PowerPoint PPT Presentation

  • Uploaded on

Investigating Organic Aerosol Loading in the Remote Marine Environment. Kateryna Lapina [email protected]

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about ' Investigating Organic Aerosol Loading in the Remote Marine Environment' - yelena

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Investigating Organic Aerosol Loading in the Remote Marine Environment


[email protected]

Colette Heald, Dominick Spracklen, Steve Arnold, James Allan, Hugh Coe, Gordon McFiggans, Soeren Zorn, Frank Drewnick, Tim Bates, Lelia Hawkins, Lynn Russell, Sasha Smirnov, Colin O’Dowd and Andy Hind

Acknowledgments: SeaWIFS and MODIS teams

Marine aod modis vs geos chem
Marine AOD: MODIS Environmentvs GEOS-Chem

From Jaeglé et al. 2011, ACP

  • New sea salt source function improves agreement of coarse AOD with MODIS

  • Remaining low GEOS-Chem bias: due to fine mode

Marine aod man vs geos chem
Marine AOD: MAN Environmentvs GEOS-Chem

  • Maritime Aerosol Network

  • provides AOD measurements from various ships of opportunity (2004 – current)



AOD < 0.4


v8-03-01 with sea salt from Jaeglé et al. 2011

What is the source of this bias?

Measurements of aerosol composition
Measurements of Aerosol Composition Environment

  • Aerodyne Aerosol Mass Spectrometer (AMS) [Jayne et al., 2000; DeCarloet al., 2006; Canagaratna et al., 2007]:

  • real-time

  • sulfate, OM, nitrate & ammonium

  • fine mode

  • Ship-based measurements during 2006 – 2008

  • Fresh pollution excluded from analysis

Possible sources of fine aod bias
Possible Sources of Fine AOD Bias Environment


Sea salt?

AOD: GC minus MODIS GC Sea salt AOD



  • Obs

  • GEOS-Chem

  • Sulfate: generally unbiased

  • Sea salt cannot account for low model bias in AOD

Marine organic matter om
Marine Organic Matter (OM) Environment

From O’Dowd et al. 2004, Nature

Mass fraction (%)

High biological activity

Mass mass (ug/m-3)

Mace Head

Chlorophyll concentrations [mg m-3]

  • Currently not included in GEOS-Chem

  • Wide range of emissions estimates: 2.3 to 75 TgC yr-1

  • [Spracklen et al., 2008; Roelofs, 2008; Langmann et al., 2008; Gantt et al., 2009; Ito and Kawamiya, 2010; Myriokefalitakis et al., 2010; Long et al., 2011; Vignati et al., 2010]

Could marine OM be the reason for low AOD bias in GEOS-Chem?

Modeling of sub micron marine om
Modeling of Sub-micron Marine OM Environment

[Chl] as a proxy for bioproductivity[O'Dowd et al., 2004; Yoon et al., 2007]

Based on Spracklen et al. 2008

Based on Langmann et al. 2008

OM = A x [Chl]

%OM = 49.129 x [Chl] + 10

OM = f([Chl], wind speed, SST)

8.9 TgC

8.2 TgC

Marine OM emissions total 8 – 9TgC

Aerosol composition model vs observations
Aerosol Composition: Model Environmentvs Observations

GC standard OM GC_Spracklen08 OM


  • Obs

  • GC standard

  • GC_Spracklen08

  • GC_Langmann08

OM obs

Large underestimation when marine OM not included

Conclusions Environment

  • The GEOS-Chem model underestimates observed surface OM when no marine OM source is included.

  • Marine OM source of <9 TgCyr-1is sufficient to account for observed marine OM concentrations.

  • The schemes developed based on satellite-derived chlorophyll-a concentrations do not adequately describe the variability in observed OM.

  • Marine OM makes a very small contribution to total marine AOD (~0.003).

Lapina et al. 2011, ACPD