The synergistic impact of SPOD and ENSO on ITCZ: observation study

Previous studies have revealed that extratropical forcing can lead to changes in the intertropical convergence zone (ITCZ). Based on reanalysis data from 1979 to 2019, this paper discusses the influence of the South Pacific Ocean Dipole (SPOD, a dominant mode between the subtropics and extratropics...

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Bibliographic Details
Published in:Climate dynamics 2023-03, Vol.60 (5-6), p.1297-1311
Main Authors: Guan, Yuanhong, Zhou, Wen, Jia, Xiaolong, Zhang, Yue, Dong, Ran
Format: Article
Language:English
Subjects:
Climatology
Convergence zones
Dipoles
Earth and Environmental Science
Earth Sciences
El Nino
El Nino events
El Nino phenomena
El Nino-Southern Oscillation event
Environmental aspects
Equator
Geophysics/Geodesy
Intertropical convergence zone
La Nina
Oceanography
Precipitation
Precipitation (Meteorology)
Southern Oscillation
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Summary:Previous studies have revealed that extratropical forcing can lead to changes in the intertropical convergence zone (ITCZ). Based on reanalysis data from 1979 to 2019, this paper discusses the influence of the South Pacific Ocean Dipole (SPOD, a dominant mode between the subtropics and extratropics in the South Pacific) and its coordination with ENSO in the ITCZ. Results show that SPOD has an effect on the position and intensity of the ITCZ, especially in the region around Niño4. From the latitudes of ITCZ axes and precipitation averaged over 160°E–160°W, positive (negative) SPOD events force a northward (southward) shift in the ITCZ in boreal winter (DJF), while the position moves in the opposite direction in boreal summer (JJA). In addition, ENSO can obviously enhance the influence of SPOD on the ITCZ. It is evident that there is a wider range of northward (southward) shift in the ITCZ under both positive SPOD and El Niño (negative SPOD and La Niña) conditions during DJF. Similar to DJF, both positive SPOD and El Niño (negative SPOD and La Niña) events still cause the ITCZ to move toward (away from) the equator during JJA, except that the magnitude of the movement in JJA is less than that in DJF. Precipitation averaged over 160°E–160°W is at a maximum under both positive SPOD and El Niño events, which have the greatest influence on ITCZ intensity, followed by both negative SPOD and La Niña in DJF, while in JJA, ITCZ intensity is most sensitive to negative SPOD events.
ISSN:0930-7575
1432-0894
DOI:10.1007/s00382-022-06335-9