Monthly and seasonal variability of dust events over northern Saudi Arabia

• Published in: International journal of climatology 2020-03, Vol.40 (3), p.1607-1629
• Main Authors: Mashat, Abdul‐Wahab S., Awad, Adel M., Alamoudi, Ahmad O., Assiri, Mazen E.
• Format: Article
• Language: English
• Subjects: Annual distribution; Atmospheric particulates; Atmospheric research; Climate; Climate studies; Climatology; Cold storage; Distribution; Dust; dust categories; Dust storms; Dynamic height; Geopotential; Mapping; Meteorological data; monthly dust variability; northern Saudi Arabia; Ozone; Pressure; Pressure cells; Seasonal distribution; seasonal dust variability; Seasonal variability; Seasonal variation; Seasonal variations; Storms; Summer; Synoptic climatology; synoptic features; TOMS aerosol index; Total Ozone Mapping Spectrometer; Troughs; Wind patterns; Winter
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.6290

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. Total (a) monthly and (b) annual distributions of weak dust observations collected for all study area stations: suspended dust (black) and blowing dust (red).