Dust emission modeling using a new high-resolution dust source function in WRF-Chem with implications for air quality

Air-borne dust affects all aspects of human life. The sources of dust have high spatial variation and a better quantification of dust emission helps to identify remediation measures. Orographic and statistical source functions allow a better estimation of dust emission fluxes in coarse-scale modeling, but a high-resolution source function is necessary to represent the highly heterogeneous nature of dust sources at the finer scale. Here we use a newly developed high-resolution (~ 500 m) source function in WRF-Chem to simulate dust emission over the Middle East and North Africa, and evaluate our simulated results against observations. Using a 4 km grid spacing, we also simulate the emission and transport of dust originating from the Tigris-Euphrates basin, one of the most important regional dust sources, and quantify the effects of this source on the air quality of the entire Arabian Peninsula. Results show that the use of new source function effectively represents the key dust sources, and provides reasonable estimates of dust optical depth and concentrations. We find that the atmospheric dust originating from the Tigris-Euphrates basin alone exceeds the PM10 air quality standards in several downwind cities. Our results have broader environmental implications and indicate that the mobilization of depleted uranium (DU) deposited in Kuwait and Southern Iraq during the Gulf War (1991) could potentially affect the urban centers over the peninsula, albeit in low concentrations. Our results suggest that an integrated and coordinated management of the Tigris-Euphrates basin is necessary to maintain good air quality across the Arabian Peninsula.

Citation

Parajuli, S. P., Stenchikov, G. L., Ukhov, A., & Kim, H. (2019). Dust emission modeling using a new high-resolution dust source function in WRF-Chem with implications for air quality. Journal of Geophysical Research: Atmospheres. doi:10.1029/2019jd030248

Sponsors

The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). We thank the Supercomputing Laboratory at KAUST for their computer support and time, as well asthe AERONET team and PIs of the individual stations for their efforts in establishing and maintaining the sites, which allowed us to use the data in our research. MODIS AOD data were downloaded from http://ladsweb.nascom.nasa.gov/data/. MERRA data were obtained from the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) available athttps://disc.sci.gsfc.nasa.gov/daac-bin/FTPSubset2.pl. CALIOP data were retrieved from the website of Atmospheric Science Data Center, NASA Langley Research Center available at https://eosweb.larc.nasa.gov/project/calipso/cloud-free_aerosol_L3_lidar_table. ECMWF Operational Analysis dataused as initial and boundary conditions for WRF-Chem simulations are restricted data; they were retrieved from http://apps.ecmwf.int/archive-catalogue/?type=4v&class=od&stream=oper&expver=1withamembership. We thank KAUST Supercomputing Laboratory for their technical support; our special thanks go to George Markomanolis for providing necessary technical assistance. We are also thankful to Warren W. Wood of Michigan State University for providing the valuable information on the occurrence of depleted uranium in the Arabian Peninsula. The first author isthankful to the colleagues Suleiman Mostamandi, Anatolii Anisimov and Udaya Bhaskar Gunturu for their encouragement and suggestions. We are thankful to Ms. Elisabeth M. Lutanie and Mr. Michael Cusack for proofreading this manuscript. A copy of the input datasets andWRF namelist specificationscan be downloaded from KAUST repositoryat https://doi.org/10.25781/KAUST-48301.