Abstract
Each movement, displacement, and change in the intertropical convergence zone (ITCZ) position play an important role in atmospheric circulation and moisture provided for precipitation systems in the North East African and Middle East regions. Accordingly, the present study aimed to evaluate the role of the Arabian subtropical high pressure (ASHP) position as part of Hadley circulation in ITCZ changes in the Indian Ocean and East African region. To this end, the ASHP displacement pattern was modeled for each month with regard to the position of the central core, expansion of the first closed curve around the central core, and the last closed curve of ASHP. The evaluation of ASHP spatial displacement demonstrated that refractions along ITCZ begin early in the winter and move steeply in the range of 40° east (the south of Sudan and Ethiopia) toward the southern latitudes as the eastward and southward displacement, as well as the expansion of ASHP and its troughs. During the summer, ITCZ is placed on the north of the equator in addition to Sudan and Ethiopia, with the deployment of the ASHP central core on the eastern shore of the Red Sea as well as the orbiting of its troughs. In conclusion, the spatial displacement of ASHP and its troughs, especially at 700 hPa and above, is assumed to be a highly important factor in the northward and southward displacement of ITCZ and its significant refraction in both winter and summer in the Horn of Africa.
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We acknowledge the European Centre for Medium-Range Weather Forecasts (ECMWF) for providing the required data for the present study. The ERA-Interim data were obtained via the ECMWF website.
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All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Hassan Lashkari and Mahnaz Jafari. The first draft of the manuscript was written by Mahnaz Jafari, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
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Lashkari, H., Jafari, M. The role of spatial displacement of Arabian subtropical high pressure in the annual displacement of the ITCZ in East Africa. Theor Appl Climatol 143, 1543–1555 (2021). https://doi.org/10.1007/s00704-020-03475-y
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DOI: https://doi.org/10.1007/s00704-020-03475-y