Assessment of natural and anthropogenic aerosol air pollution in the Middle East using MERRA-2, CAMS data assimilation products,and high-resolution WRF-Chem model simulations

Abstract

<p><strong>Abstract.</strong> Modern-Era Retrospective analysis for Research and Applications v.2 (MERRA-2), Copernicus Atmosphere Monitoring Service Operational Analysis (CAMS-OA) data assimilation products, and a regional Weather Research and Forecasting model (10 km resolution) coupled with Chemistry (WRF-Chem) were used to evaluate natural and anthropogenic aerosol air pollution in the ME during 2015–2016. Satellite and ground-based AOD observations, as well as in-situ Particulate Matter (PM) measurements for 2016, were used for validation.</p> <p>WRF-Chem code was modified to correct the calculation of dust gravitational settling and aerosol optical properties. The dust emission in WRF-Chem is calibrated to fit Aerosol Optical Depth (AOD) and aerosol volume size distributions obtained from Aerosol Robotic Network (AERONET) observations. MERRA-2 was used to construct WRF-Chem initial and boundary conditions both for meteorology and chemical/aerosol species. SO<sub>2</sub> emissions in WRF-Chem are based on the novel NASA SO<sub>2</sub> emission dataset that reveals unaccounted sources over the ME.</p> <p>Although aerosol fields in WRF-Chem and assimilation products are quite consistent, WRF-Chem, due to its higher spatial resolution and better SO<sub>2</sub> emissions, is preferable for analysis of regional air-quality over the ME. The WRF-Chem's PM background concentrations exceed the World Health Organization (WHO) guidelines over the entire ME. The major contributor to PM (~ 75–95 %) is mineral dust. In the ME urban centers and near oil recovery fields, non-dust aerosols (primarily sulfate) contribute up to 26 % into PM<sub>2.5</sub>. The contribution of sea salt into PM can rich up to 5 %. The contribution of organic matter into PM prevails over black carbon.</p>

Interaction of Dust Aerosols with Land/Sea Breezes over the Eastern Coast of the Red Sea from LIDAR Data and High-resolution WRF-Chem Simulations

“…This dataset does not account for SO2 emissions produced by ships; therefore, we take ship SO2 emissions from the EDGAR v4.3.2 dataset. OMI-HTAP emissions in WRF-Chem are satisfactorily reproduced by the observed SO2 loading in the Middle East region (Ukhov et al, 2020a).…”

“…Sulfur dioxide (SO2) is of particular concern because it chemically transforms in the atmosphere into secondary sulfate, which is an important and influential aerosol at our study site (Ukhov et al, 2020a, Ukhov et al, 2020b. To achieve a more accurate representation of sulfate aerosols, we use the SO2 emissions from a time-varying (monthly) inventory developed by NASA for the same year (2015).…”

“…Furthermore, the study site has several industrial areas nearby that produce anthropogenic emissions of sulfur dioxide (SO2), and black and organic carbon (BC and OC) (Ukhov et al, 2020a). Because the site is located exactly at the land-ocean boundary, some unique small-scale processes exist that affect the local climate of this region.…”

Study of SO Pollution in the Middle East Using MERRA‐2, CAMS Data Assimilation Products, and High‐Resolution WRF‐Chem Simulations

“…The WRF‐Chem model is extensively used for prediction and simulation of weather, dust storms, and aerosol interactions with atmosphere and radiation (Anisimov et al, ; Cahill et al, ; Jish Prakash et al, ; Kalenderski & Stenchikov, ; Osipov & Stenchikov, ; Parajuli et al, ). For air‐quality research the WRF‐Chem model has been used in many regions of the globe: East Asia (Wang et al, ), the United States (Chuang et al, ; Kim et al, ), Europe (Forkel et al, ; Ritter et al, ), South America (Archer‐Nicholls et al, ), and ME (Ukhov et al, ).…”

“…In this study we focus on the ME, which is one of the most polluted areas in the world. Because of extremely high levels of natural particulate pollution driven by dust aerosols (Jish Prakash et al, 2016;Kalenderski & Stenchikov, 2016;Parajuli et al, 2019;Tsiouri et al, 2015), the region experiences extreme pollution episodes, compounded by a strong contribution of anthropogenic aerosols and gases (Ahmed, 1990;Barkley et al, 2017;Karagulian et al, 2015;Lelieveld, Beirle, et al, 2015;Lelieveld et al, 2009;Ukhov et al, 2020). ME emits CAMS-OA uses anthropogenic emissions from the MACCity inventory (Granier et al, 2011) on a 0.5 • × 0.5 • grid built over the period 1960-2010 (see Figure 1a).…”