Summer shamals over the Arabian Gulf

Migration of Barchan Dunes in Qatar–Controls of the Shamal, Teleconnections, Sea-Level Changes and Human Impact

“…A low-pressure center along this southward moving front in the northern Arabian Gulf and a surface high-pressure cell over the northern Arabian Peninsula finally induce the winter Shamal, which is not as consistent as its summer counterpart [31]. The Shamal triggers severe dust storms, which represent a high-frequency hazard to different types of operational services (e.g., aviation) in the Gulf region [32]. The long-term persistence of dominating winds from 290 • -010 • is also reflected by the alignment of the main axis of nebkhas and sand drapes at prehistoric burial cairns, by micro-yardangs inside the inland sediment-filled depressions (rawdhat), or sandblasting features on rock surfaces in most parts of the peninsula ( Figure 3).…”

“…The wind regime is dominated by the NW to N regional Shamal winds approaching Qatar mostly during early June to mid-July and November to March, respectively [31] (Figure 2). This regional wind system mostly affects Saudi Arabia, Kuwait, and Qatar [32], and controls the movement of barchans in SE Qatar [10]. In May, the summer Shamal is mainly determined by a lower to middle tropospheric westerly trough over Iran and a corresponding ridge over Anatolia resulting in atmospheric descent over the northern Arabian Peninsula and the creation of a regional anticyclone.…”

“…In May, the summer Shamal is mainly determined by a lower to middle tropospheric westerly trough over Iran and a corresponding ridge over Anatolia resulting in atmospheric descent over the northern Arabian Peninsula and the creation of a regional anticyclone. In combination with an established heat low over Iran, these conditions initiates short-term, multiple-day Shamal activity over Qatar [32] with surface wind speeds of up to 13 m/s [33]. Stronger and longer-duration Shamals during June and July are controlled by a steep gradient between the Mediterranean high-pressure cell, and the regional depression over Iran and adjacent areas resulting from extreme heating of surface air masses [32,34,35].…”

“…In combination with an established heat low over Iran, these conditions initiates short-term, multiple-day Shamal activity over Qatar [32] with surface wind speeds of up to 13 m/s [33]. Stronger and longer-duration Shamals during June and July are controlled by a steep gradient between the Mediterranean high-pressure cell, and the regional depression over Iran and adjacent areas resulting from extreme heating of surface air masses [32,34,35]. The winter Shamal (November to March) may even reach wind speeds of 15-20 m/s over the Arabian Gulf [35,36], and is usually associated with a surface low-pressure area over Syria migrating eastward towards Iran and pushing a cold front south and west.…”

Coastal effects on radar propagation in atmospheric ducting conditions

“…The approach was to use two models, a numerical atmospheric model and a radar propagation model, in a case study of one day on which detailed observations of ducts and radar propagation were available in part of the Persian Gulf (Brooks et al 1999). The day, 28 April 1996, was a typical shamal day, 'shamal' being the name given to strong north-westerly winds in this area, which frequently occur in both warm and cold seasons (Rao et al 2003).…”