The role of the Arabian anticyclone core position in the spatial displacement of precipitation cores and moisture transport pathways of precipitating systems (Affecting southern Iran)

The general structure of synoptic patterns in any region develops out of the interaction among several systems, among which one or two systems have more prominent roles compared to the others. In Western Asia, the Arabian subtropical Anticyclone (ASTAC) system has a determining role in the structure of the atmospheric patterns of the region. This research was conducted with the aim of investigating the role of this system in the spatial displacement of high-pressure cores and the track of precipitation systems in Iran. This study analyzed ۴۰ strong precipitation systems in the southern part of Iran. First, the atmospheric data of these systems were extracted from the NCEP/NAR site for ۴۸ h up to the end of the precipitation period across all troposphere levels. The high-pressure central core was extracted across all levels, and eventually, the cores of ۷۰۰ hPa were chosen to locate the site of deployment of the cores. Then, the combined maps of the special stream and moisture, as well as the altitude maps for routing the system, humidity advection, and spatial displacement of Mediterranean trough at the levels of ۸۵۰ and ۷۰۰ HPa were chosen. The precipitation distribution map of each system was prepared, and the high-precipitation core was determined. Finally, the distance between the precipitation and high-pressure cores was measured. The findings indicated that the high-pressure cores of ASTAC were established in four general regions. The placement location of the cores determined the track of precipitation systems towards Iran and the precipitation zone of each system. In all cases, the humidity of systems was first advected through ASTAC cellular anticyclonic circulation over Sudan and Ethiopia (Sudan low). They were then advected through the southern streams of the Mediterranean trough over Arabia and Iran. The protraction and depth of troughs also had a close relationship with the location of ASTAC core establishment in a way that the high-pressure cores had a westward displacement. The same occurred for the axes of troughs and vice versa.

کلیدواژه ها:

Arabian Subtropical Anticyclone ، Iran ، Low Pressure Sudan ، Moisture advection ، Routing Precipitation Systems