Sensitivity of WRF-chem predictions to dust source function specification in West Asia

Author(s)
Seyed Omid Nabavi, Leopold Haimberger, Cyrus Samimi
Abstract

Dust storms tend to form in sparsely populated areas covered by only few observations. Dust source maps, known as source functions, are used in dust models to allocate a certain potential of dust release to each place. Recent research showed that the well known Ginoux source function (GSF), currently used in Weather Research and Forecasting Model coupled with Chemistry (WRF-chem), exhibits large errors over some regions in West Asia, particularly near the IRAQ/Syrian border. This study aims to improve the specification of this critical part of dust forecasts. A new source function based on multi-year analysis of satellite observations, called West Asia source function (WASF), is therefore proposed to raise the quality of WRF-chem predictions in the region. WASF has been implemented in three dust schemes of WRF-chem. Remotely sensed and ground-based observations have been used to verify the horizontal and vertical extent and location of simulated dust clouds. Results indicate that WRF-chem performance is significantly improved in many areas after the implementation of WASF. The modified runs (long term simulations over the summers 2008–2012, using nudging) have yielded an average increase of Spearman correlation between observed and forecast aerosol optical thickness by 12–16 percent points compared to control runs with standard source functions. They even outperform MACC and DREAM dust simulations over many dust source regions. However, the quality of the forecasts decreased with distance from sources, probably due to deficiencies in the transport and deposition characteristics of the forecast model in these areas.

Organisation(s)
Department of Meteorology and Geophysics
External organisation(s)
Universität Bayreuth
Journal
Aeolian Research
Volume
24
Pages
115-131
No. of pages
17
ISSN
1875-9637
DOI
https://doi.org/10.1016/j.aeolia.2016.12.005
Publication date
08-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
105906 Environmental geosciences, 105206 Meteorology
Keywords
ASJC Scopus subject areas
Earth-Surface Processes, Geology
Portal url
https://ucrisportal.univie.ac.at/en/publications/sensitivity-of-wrfchem-predictions-to-dust-source-function-specification-in-west-asia(e4f79f0f-5376-41fc-9c38-6a0001fe3d0d).html