The QUEST Working Group on Dust met for the first time in November 2007 to develop a strategy for collaborative research to improve understanding of the dust cycle under past, present and future climates.

CLIVAR Exchanges news article on the first QUEST WGD Meeting can be found here.

NOVEMBER 2007 WORKSHOP

Some of the key recommendations from the meeting:

Model improvements. There needs to be a major emphasis on the characterisation of source regions for modelling. This needs to build on the ongoing investigations of the geomorphic controls on dust emissions. New global data sets that allow the physical and chemical properties of material in potential source areas need to be developed, through refining available global input data sets using information derived from field studies. Continued work on the sensitivity of radiative forcing to the specification of dust physical properties is important as it will serve to guide the creation of such data sets.

Data requirements. Tools and protocols for benchmarking dust-cycle model simulations under modern and past conditions need to be developed. The DIRTMAP database provides a useful tool for validating spatial patterns in dust deposition under both present-day and palaeo-climates states, but urgently needs to be updated and expanded. The emphasis should be on including records from areas currently under-represented in the database, such as South America, Eurasia, the Middle East and the Southern Ocean. Priority should also be given to including high-resolution sediment records that document changes in dust deposition during climate oscillations such as Dansgaard-Oeschger events.

Documenting stratigraphic changes in size characteristics, and drawing on new high-resolution particle size analysis techniques that permit quantification of the sub-micron scale particles (most relevant to radiative modelling) is important. Mineralogical and isotopic information relevant to provenancing, radiative forcing and bio-fertilisation should be included in the database. Finally, because of the diversity of the records already included in the database, more metadata needs to be included in the database to facilitate the selection of records for specific types of model evaluation in an objective way.

Modelling strategy. There are many opportunities for using observations and carefully-designed model simulations to understand changes in the dust cycle. Meso-scale models, for example, could provide an opportunity to test global model parameterisations of spatial heterogeneity in dust emissions. Dust-cycle feedbacks are not yet incorporated dynamically into simulations of past climates. There is clearly a need to design transient simulations with fully-coupled climate-dust models to address the potential role of dust in abrupt climate changes.

The next meeting of the QUEST Dust Working Group, to be held in the autumn of 2008, will focus in more detail on dust-source modelling and characterisation.

Left to right: (back) Jim Beget, Hubertus Fischer, Art Bettis, Jean-Robert Petit, Paul Hesse, Adam Durant; (middle) Helen Roberts, Peter Croot, Joanna Bullard, Sandy Harrison; (front) Yves Balkanski, Dennis Rousseau, Hezi Gildor, Doug Mackie, Barbara Maher