On the Relationship between Circulation Patterns, the Southern Annular Mode, and Rainfall Variability in Western Cape
Please always quote using this URN: urn:nbn:de:bvb:20-opus-241018
- This study investigates circulation types (CTs) in Africa, south of the equator, that are related to wet and dry conditions in the Western Cape, the statistical relationship between the selected CTs and the Southern Annular Mode (SAM), and changes in the frequency of occurrence of the CTs related to the SAM under the ssp585 scenario. Obliquely rotated principal component analysis applied to sea level pressure (SLP) was used to classify CTs in Africa, south of the equator. Three CTs were found to have a high probability of being associated withThis study investigates circulation types (CTs) in Africa, south of the equator, that are related to wet and dry conditions in the Western Cape, the statistical relationship between the selected CTs and the Southern Annular Mode (SAM), and changes in the frequency of occurrence of the CTs related to the SAM under the ssp585 scenario. Obliquely rotated principal component analysis applied to sea level pressure (SLP) was used to classify CTs in Africa, south of the equator. Three CTs were found to have a high probability of being associated with wet days in the Western Cape, and four CTs were equally found to have a high probability of being associated with dry days in the Western Cape. Generally, the dry/wet CTs feature the southward/northward track of the mid-latitude cyclone, adjacent to South Africa; anti-cyclonic/cyclonic relative vorticity, and poleward/equatorward track of westerlies, south of South Africa. One of the selected wet CTs was significantly related to variations of the SAM. Years with an above-average SAM index correlated with the below-average frequency of occurrences of the wet CT. The results suggest that through the dynamics of the CT, the SAM might control the rainfall variability of the Western Cape. Under the ssp585 scenario, the analyzed climate models indicated a possible decrease in the frequency of occurrence of the aforementioned wet CT associated with cyclonic activity in the mid-latitudes, and an increase in the frequency of the occurrence of CT associated with enhanced SLP at mid-latitudes.…
Author: | Chibuike Chiedozie Ibebuchi |
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URN: | urn:nbn:de:bvb:20-opus-241018 |
Document Type: | Journal article |
Faculties: | Philosophische Fakultät (Histor., philolog., Kultur- und geograph. Wissensch.) / Institut für Geographie und Geologie |
Language: | English |
Parent Title (English): | Atmosphere |
ISSN: | 2073-4433 |
Year of Completion: | 2021 |
Volume: | 12 |
Issue: | 6 |
Article Number: | 753 |
Source: | Atmosphere 2021, 12(6), 753; https://doi.org/10.3390/atmos12060753 |
DOI: | https://doi.org/10.3390/atmos12060753 |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 551 Geologie, Hydrologie, Meteorologie |
Tag: | Africa south of the equator; Southern Annular Mode; Western Cape; circulation type; mid-latitude cyclone |
Release Date: | 2022/01/10 |
Date of first Publication: | 2021/06/10 |
Collections: | Open-Access-Publikationsfonds / Förderzeitraum 2021 |
Licence (German): | CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International |