COARSEMAP: synthesis of observations and models for coarse-mode aerosols

A new project, coordinated by Heikki Lihavaien, Natalie Mahowald, Ron Miller and Christine Wiedinmyer

Coarse mode aerosols are important for climate and biogeochemistry, especially due to their long-wave interactions, ice nucleation and contributions to important elements for biogeochemistry.  Yet coarse mode aerosols have received less emphasis in the scientific literature than fine mode aerosol.  Here we present first efforts to globally synthesize available mass concentration, composition and optical depth data and modeling for the coarse mode (>1 µm) aerosols in a new project called “COARSEMAP”. We seek more collaborators who have observational data, especially including elemental or composition data or who are interested in detailed modeling of the coarse mode.  The goal will be publications synthesizing data with models, as well as providing synthesized results to the wider community.

We will present this project at AEROCOM and AGU and will host information here shortly!

For more information or to join the project, please send an email to Natalie Mahowald. (

If you would like to contribute, please fill out the excel spread-sheet and send to Natalie, to add your data to the list. (email addresses will not be posted directly).

Current list of collaborators (over 60)

Current set of metadata



In progress:

  • Task 1: Gather meta data on coarse mode observational in situ data
  • Task 2: Compile observational data and synthesize


  • Task 3: Publish synthesis
  • Task 4: Compare to remote sensed and model output
  • Use for model inter-comparisons

Email to the community: sent September, 2017:


We are emailing you as a potential collaborator for the COARSE-MAP project.  We plan to compile and synthesize available observations and model output quantifying the coarse aerosol size fraction.  While coarse mode (<10mm) particles are important for ice nucleation, long wave interactions and biogeochemistry, they have not received the attention that fine mode aerosols have in recent studies.

Our first task is to identify what data is available.  We ask you to contribute the information in this spreadsheet, either for in situ or remote sensing observations or model results for the coarse mode.  Data taken at the same time or place that helps attribute the coarse mode to different sources (e.g. sulfate or BC) would also be valuable.

We plan to host a maintained table of data owners on our web site. With your consent, we would include your email address (with the @ replaced with at so that automatic emailers can’t catch it). We would also like to include this information in scheduled presentations at AEROCOM and AGU this fall, and future meetings.  Any contributions to the table received in time for these meetings would include your name as a present collaborator in all presentations describing the project, and as we solicit more data.

We will also be collecting the data, especially in situ observations, and compiling it into time averages that are convenient for comparison to models.  If you would like to contribute your data to this effort, for future publication, we would offer you co-authorship on any resulting papers with the right to withdraw your data from any paper or synthesis if you wish. We also welcome comments, suggestions and assistance with manuscript production. Your data will never be passed to other people without your express permission. Our ideal would be to consistently process the data, and make annual or monthly averages available to the wider scientific community and public in a published paper, while pointing people to the data owners for the original data.  Please include the names of all people who should be offered co-authorship in these tables, so we ensure all contributors are appropriately acknowledged.

We also plan to include data in the table and compilations that are already compiled within other networks, such as EMEP, EPA, AERONET or satellite data already posted on relevant websites.

In the future, we plan model/data intercomparisons: at this point we want to document which models include coarse mode aerosols and focus on the synthesis of observations.  If you include details about your model, this will be included on the webpage, and we would include you in discussions about model/data intercomparisons.

Attached is the spreadsheet for documentation of your data set. Notice that we have filled in the first rows as examples to aid in filling out the table. 

Please let us know any questions you have. Comments or suggestions are also welcome.


Heikki Lihavainen, Natalie Mahowald, Ron Milller, Christine Wiedinmyer

COARSE-MAP coordinators