Monthly and seasonal variability of dust events over northern Saudi Arabia

Abstract

The monthly and seasonal variability and distribution of dust events over northern Saudi Arabia were studied using ground‐based measurements from 11 surface stations for the period of 1978–2010. Additionally, to study the synoptic climatology of the dust variability, the aerosol index (AI) data from the Total Ozone Mapping Spectrometer (TOMS) satellite and meteorological data from the National Center for Environmental Prediction and National Center for Atmospheric Research (NCEP/NCAR) reanalysis datasets were used. The dust types observed at the surface stations are classified into two categories: weak dust and dust storms. A statistical study of the ground measurements demonstrated that weak dust category events are prevalent in the cold months, whereas storm category events are prevalent in the hot months. Additionally, the annual distribution distinguishes two periods for dust observations, before and after 1989, where the number of events in the first period is lower than the annual average but increases during the second period. The synoptic climate study indicated that two main atmospheric wind patterns, anticyclonic and northerly (shamal) patterns, accompany the dust events in the study area. The dust in winter and autumn is mainly affected by the anticyclonic pattern, while that in spring and summer is mainly affected by the shamal pattern. In addition, a synoptic study of selected cases confirmed the climate results and demonstrated the existence of two atmospheric patterns corresponding to winter and summer. Both patterns include troughs over the Red Sea and Arabian Gulf and a ridge or high‐pressure cell over the eastern Mediterranean region during the summer atmospheric pattern and over the mid‐Arabian Peninsula during the winter atmospheric pattern. The characteristic of non‐dust storm composition demonstrated that the storms exhibit pronounced synoptic systems (winter and summer) with the highest pressure/geopotential gradient near the Arabian Peninsula.

Global Dust Variability Explained by Drought Sensitivity in CMIP6 Models

“…Some studies (e.g., Mahowald et al, 2010) attribute the trends in the North African dust to the severe precipitation deficit while Cowie et al (2013) emphasize the role of surface wind speed on the dust trends. Similarly, the dominant role of wind speed on the dust variability over the Middle East was reported by Kamal et al (2020) and Mashat et al (2020). In these cases, the drought relationships we find are likely the result of wind variability associated with drought in these regions.…”

Classification of aerosols over Saudi Arabia from 2004–2016

“…Moreover, seasonal distributions (Figure 3) show the highest AAOD (greater than 0.03) in spring, and over the Eastern and Southern provinces, followed by summer, winter, and autumn. The reason for high AAOD during spring is the peak dust storm happens in this season when dust storms are originated or transported from the Sahara Desert by depressions passing eastwards over the Mediterranean Sea, the strong ground solar heating produces turbulence, local pressure gradients, and shamal pattern (Shao, 2008;Prakash et al, 2015;Mashat et al, 2019). The month of April to May (spring) is characterized by peak dustiness over Eastern and May-June over the Southern and Central regions of Saudi Arabia (Yu et al, 2013).…”

“…In addition, the increased AAOD in winter may also reflect an enhanced presence of absorbing aerosols (BC, biofuel burning) during wintertime. The anticyclonic pattern is developed in autumn leading to weak dust activity resulting lowest columnar AAOD over Saudi Arabia (Kang et al, 2017;Mashat et al, 2019). and more absorbing aerosols over Solar village may be due to a large number of dust storm events compared to the KAUST region as calculated using ground-based Meteorological station data (Butt et al, 2017).…”

“…For example, low values of FMF vs. AE indicate coarse mode dust aerosol (Aloysius et al, 2009); and high values of FMF (> 0.6) and intermediate values of AAE (1.0 < AAE < 2.00) indicate BC aerosols (Giles et al, 2011). Similarly, values of SSA (SSA ≤ 0.95) and high values of FMF also indicate BC aerosols (Lee et al, 2010;Giles et al, 2012 to frequent dust storms (Awad and Mashat, 2014;Almazroui et al, 2015;Awad et al, 2015;Kumar et al, 2018;Ali and Assiri, 2019;Mashat et al, 2019Mashat et al, , 2020. However, the booming oil, and gas industry generating unprecedented economic growth, have stimulated, rapid urbanization and industrial Farahmandkia et al (2010) in Tehran.…”

Major Changes in Extreme Dust Events Dynamics Over the Arabian Peninsula During 2003–2017 Driven by Atmospheric Conditions

“…Several studies have described the mechanisms of formation of dust storms over AP using observations and models (e.g., Alharbi, 2013;Maghrabi et al, 2011;Miller et al, 2008Miller et al, , 2019. The residing anticyclonic circulation in autumn and winter was suggested to be responsible for the formation of dust storms (Mashat et al, 2018(Mashat et al, , 2019. Dust activity in spring is driven by Mediterranean cyclones and associated cold fronts (Notaro et al, 2015).…”