TITLE:
Local and Time Changes over a 66-Year Period and Annual Relocation of Saudi Arabian Subtropical High Pressure
AUTHORS:
Hasan Lashkari, Ali Akbar Matkan, Zainab Mohammadi
KEYWORDS:
Analysis, Time and Local Change, Subtropical High Pressure, Saudi Arabia
JOURNAL NAME:
Open Journal of Geology,
Vol.6 No.9,
September
14,
2016
ABSTRACT: Saudi
Arabian subtropical high pressure is a major system affecting general
circulation of the atmosphere of west Asia. Its annual relocation affects the
relocation of other systems in the area, such as Mediterranean cyclones,
Sudanese low pressure areas, and west wind waves. This system is known to
relocate to the south and north in response to outward solar relocation, but
the reasons behind its eastern and western relocation have not been studied
thoroughly. The present study examined 1000 and 850 HPa levels over the course
of 66 years (1948-2015) to determine a pattern of latitudinal and longitudinal
relocation of the system using synoptic maps. The research showed that, after 2008, high pressure latitudinal and
longitudinal swings were larger than in previous years and the annual high
pressure relocation was not in concord with the apparent motion of the sun. At
the onset of autumnal moderation, the high pressure core was positioned to the
north of Saudi Arabia (22°- 30°north latitude and 42°- 50°south longitude). Southern movement
continued until the end of March, when the core again relocated to the north.
These relocations first occurred slowly, but the northern relocation occurred
very quickly from May to June, such that the core moved northward 22°to 30°. After June, the core did not relocate much until the end of September.
After September, it relocated strongly south in all time periods. It was noted
that high pressure over Saudi Arabia had two cores from June to September in
some years; in others the high pressure core was in southwestern Iran and Iraq.
In still others, a southwest to northeast high pressure tab entered Iran from
the southwest (Khuzestan) and continued northward with a core forming in the
northern Caspian Sea.