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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Extreme Intertropical Convergence Zone shifts over Southern Maritime Continent

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Author(s):
Vasques Freitas, Ana Carolina ; Aimola, Luis ; Ambrizzi, Tercio ; de Oliveira, Cristiano Prestrelo
Total Authors: 4
Document type: Journal article
Source: Atmospheric Science Letters; v. 18, n. 1, p. 2-10, JAN 2017.
Web of Science Citations: 1
Abstract

This study investigated the Intertropical Convergence Zone (ITCZ) extreme shifts in the Southern Maritime Continent (SMC) region in austral spring during the period 1979-2015. The results have shown that the ITCZ Southern Boundary (SB) presents great correlations with a meridional Sea Surface Temperature (SST) gradient and Indian Ocean Dipole (IOD) events. However, besides these local forcing, the extreme ITCZ shifts are also influenced by El Nino-Southern Oscillation (ENSO) events and an associated zonal SST gradient. The extreme shifts are due mainly to the combination of changes in Walker Circulation (WC) in the Pacific and Indian Ocean (IO) and local SST anomalies. Therefore, during ITCZ southward extreme shifts, the WC is stronger leading to the strengthening of the northwest equatorial winds in the IO, which pumps moist air and boosts the diabatic heating in the SMC due to the local positive SST anomalies present in this region. Otherwise, during northward extreme shifts, the WC is weaker, not allowing the performance of the northwest equatorial winds in the IO, which associated with the local negative SST anomalies, leads to drier conditions in the SMC region. Another interesting result found here is that a strong meridional or zonal index not necessarily implies a larger shift. The combination of very strong ENSO and IOD events can lead to greater ITCZ SB shifts. Besides, the ITCZ SB shifts can act as a bridge linking IOD and ENSO. (AU)

FAPESP's process: 15/50324-2 - Untangling the drivers of ocean variability in the Southwest Atlantic
Grantee:Tercio Ambrizzi
Support type: Regular Research Grants
FAPESP's process: 08/58101-9 - Impact of the Southwestern Atlantic Ocean on South American climate for the 20th and 21st centuries
Grantee:Tercio Ambrizzi
Support type: Research Program on Global Climate Change - Thematic Grants