The Southern Hemisphere Blocking Index in the ERA5 and the NCEP/NCAR Datasets: A Comparative Climatology for the Period 1940–2022
Blocking anticyclones are important atmospheric phenomena generally associated with extreme weather (e.g., droughts and cold air surges). Blockings also constitute largescale indicators of climate change. The study of blockings in the Southern Hemisphere (SH) has been traditionally carried out uti...
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| Autores principales: | , , |
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| Formato: | Libro |
| Lenguaje: | Inglés |
| Publicado: |
MDPI
2025
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| Materias: | |
| Acceso en línea: | https://repositorio.uca.edu.ar/handle/123456789/19956 https://doi.org/10.3390/atmos16060719 |
| Aporte de: |
| Sumario: | Blocking anticyclones are important atmospheric phenomena generally associated
with extreme weather (e.g., droughts and cold air surges). Blockings also constitute largescale indicators of climate change. The study of blockings in the Southern Hemisphere
(SH) has been traditionally carried out utilizing reanalysis products. This paper is aimed
at presenting an updated, comprehensive climatology of blockings in the SH as extracted
from the ERA5 and the NCEP/NCAR reanalysis datasets in the 1940–2022 and 1948–2022
periods, respectively. Blockings were located by means of a unidimensional index at
500 hPa. The results were stratified by season, longitude, region, persistence, and intensity,
and the climatology from both datasets was compared. The primary location of blockings
was close to the Date Line in every season. Additionally, depending on the season, up to
fourth-rank maxima could be located. Generally, the secondary maxima were found in
the south Atlantic; lower-order maxima were located in the south-eastern Pacific, west of
South America, and in the south-western Indian Ocean east of South Africa. The most
intense blockings were concentrated in the Pacific and in the south Atlantic in both datasets,
and they were also located in the Indian Ocean, but in the ERA5 reanalysis only. The
longest-lived blockings occurred in the south Pacific and in the south Atlantic during
southern winter. |
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