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SDS-WAS webinar: Insights into dust emission mechanisms from field measurements, theory, and modeling

by Enric Terradellas last modified Apr 26, 2017 03:50 PM
When May 11, 2017
from 01:00 PM to 02:00 PM
Where online (13:00-14:00 UTC)
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The SDS-WAS Regional Center for Northern Africa, Middle East and Europe cordially invites you to the following free online presentation:
  • Title: Insights into dust emission mechanisms from field measurements, theory, and modeling
  • Speaker: Martina Klose - USDA-ARS Jornada Experimental Range
  • Date and time: 11 May 2017 13:00 - 14:00 UTC
  • How to attend it: Webex access (Meeting number: 233 673 897).  NOTE: Please, check the Webex access before the webinar. You can check Webex FAQs here.

Please, note that remote attendance is limited to 100 persons on a first-come, first-served basis. The presentation will be later made available here.

Abstract

Numerical modeling is vital to study mineral dust and its diverse impacts on the environment and human daily life. Parameterizations of dust emission in models are based on theories about the dust emission mechanisms: saltation bombardment, aggregate disintegration, and aerodynamic entrainment. Testing of such theories needs field measurements as an input.  To date, most measurements do not provide enough information to allow for a determination of the dust emission mechanism and often focus on a small variety of soil and atmospheric settings. Hence, the evaluation of dust emission parameterizations has so far relied on a selective set of observations. Here, preliminary results will be presented of a study that aims to decipher dust emission mechanisms from field measurements for a range of land-surface and atmospheric conditions. The preliminary results show that particle-size characteristics of surface and transported sediment together with the land-surface properties can provide insights about saltation-based dust emission mechanisms and that considerable dust emission occurs in situations “sub-optimal” for sediment entrainment. Aerodynamic entrainment is hard to isolate from field measurements in an uncontrolled environment, but does occur if free dust is available. Theory suggests that the threshold friction velocity for the entrainment of dust can be as low as that for sand. A parameterization for aerodynamic entrainment will be presented and used to estimate dust devil dust emission on small and large spatial scale.

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