Abstract
An objective method was developed to detect local cells of the Siberian high (SH) over the Middle East, and mean sea level pressure (SLP) data from the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis dataset were used to specify the centers of local SH cells and associated ridges. The results indicated that approximately 25.8% of winter SH cells influence the Middle East, and this influence diminishes from December to February. Synoptically, the area between the Black and Caspian Seas represents a remote area for sensing the influences of the SH on the Middle East. Although the SH is considered a shallow system, the variability of the effectiveness of the SH throughout the Middle East was estimated from the integration of atmospheric systems at the whole-atmosphere scale (from the surface to 200 hPa). Further, this study demonstrated that the westward extension of the SH over the Middle East is associated with weak cyclogenesis in the area between the Black and Caspian Seas; that is, the atmospheric systems are favourable for strengthening the upper-layer ridge in this area. However, the eastward retreat of the SH extension from the Middle East is associated with strong cyclogenesis in the area between the Black and Caspian Seas; that is, the atmospheric systems are unfavourable for strengthening the upper-layer ridge in this area. This study revealed the importance of the SH in the generation of the pressure gradient over the Arabian Peninsula and the associated development of dust storms and the Red Sea Trough.