The inner life of the Atlantic Intertropical Convergence Zone

Windmiller, Julia M.; Stevens, Bjorn

doi:10.1002/qj.4610

“…This is what we have also found even with slightly different longitudinal dimension in definition of the Indian Ocean (60°E -100°E in this study). Our result is, again, similar to the recent Windmiller and Stevens (2023) conclusion that the maximum precipitation (in July and August) over the Atlantic ocean is closely aligned to the wind confluence determined using a combination of ERA5 datasets and the data collected through the German research Vessel (SONNE).…”

Section: Neutralsupporting

confidence: 90%

“…On the contrary, there is an improved zonal ITCZ position alignment between the minimum divergence and the location of maximum precipitation over much of the regions during the Austral winter related seasons (see Appendix G). This is well aligned to Windmiller & Stevens (2023) observation over the Atlantic ocean.…”

Section: Neutralsupporting

confidence: 88%

Response of the global ITCZ to different ENSO phases and how the ITCZ determined from the maximum precipitation compares with the surface tropical winds convergence

Ramotubei,

Landman,

Mateyisi

et al. 2024

Preprint

0

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The position of the intertropical convergence zone (ITCZ) may lead to drying/flooding in some parts of the world. Its spatial and temporal variation responds to well-established oscillation processes like the El-Niño-Southern Oscillation (ENSO). This research establishes the response of the ITCZ position to the ENSO phases and how its position, determined from maximum precipitation, relates to the convergence of surface tropical winds. The ERA5 reanalysis data, 1990 – 2020, is used in this study. Each longitude is scanned for latitude of maximum precipitation, during each El-Niño/La-Niña/Neutral years, within the 20°N/S latitude range to identify the ITCZ position. The study concludes that the position established by the maximum precipitation aligns with the surface tropical winds convergence over the global oceanic areas. On seasonal average, the La-Niña related ITCZ position is consistently southward of its El-Niño position over Africa and Central Pacific Ocean. The study uncovered that the extreme cases of El-Niño/La-Niña leads to further north/south shifting of the ITCZ position from its normal El-Niño/La-Niña positions. The continental and Atlantic Ocean ITCZ is more persistent and shows a minimal fluctuation during the El-Niño/La-Niña. Over Africa, cross-wavelet analysis shows common high-power features in the Oceanic Niño Index (ONI) and ITCZ signals over a four-year periodicity, mirroring the ENSO periodicity albeit with slowly varying time lag across the years. The cross-correlation of the two signals is strongest in Austral summer (DJF). The global and temporal ITCZ shifts open an opportunity for improved interpretation of seasonal forecasts of hydroclimatic events, especially under climate change conditions

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“…The Intertropical Convergence Zone (ITCZ) is a large-scale atmospheric system originating from the ascending branch of the Hadley cell [1] . It manifests near the equator in various atmospheric fields as a band of trade wind convergence, minimum in atmospheric pressure, minimum in outgoing longwave radiation (OLR), deep convective clouds, and frequent intermittent rain events that transfer freshwater from the atmosphere to the ocean [2][3][4][5][6][7][8][9][10][11] . These characteristics do not necessarily occur simultaneously and/ or in the same location [7,12] .…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Intertropical Convergence Zone over the Atlantic Ocean through an Algorithm Based on Precipitation

Chrysostomo de Oliveira Nogueira,

Gomes Machado,

Simões Reboita

et al. 2024

j. of atmos. sci. res.

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The Intertropical Convergence Zone (ITCZ) is a key atmospheric system on a global scale, primarily driven by trade wind convergence near the equator. The ITCZ plays a crucial role in modulating the climate of the borders of tropical continental areas. For instance, Northeastern Brazil experiences a climate influenced by the ITCZ over the Atlantic Ocean. In some periods, the ITCZ exhibits double bands, known as the double ITCZ. While the features of the ITCZ have been described using various approaches and atmospheric variables, there is still a lack of regional studies focusing on the ITCZ and double ITCZ in the Atlantic Ocean. In this context, the main goals of this study are (1) to describe a simple algorithm based on precipitation to identify the ITCZ and double ITCZ, (2) to present a climatology (1997–2022) of the position, width, and intensity of these two convective bands, and (3) to investigate variabilities in the ITCZ characteristics associated with anomalies of sea surface temperature (SST) in the tropical Pacific and Atlantic oceans. The double ITCZ typically occurs southward of the main cloud band, and between February and April, both bands are more distant (~4.5°). In the western sector of the Atlantic Ocean, the ITCZ and its double band extend to more southerly latitudes in austral autumn. Considering the entire Atlantic basin, the annual mean of the latitudinal position, width, and intensity of the ITCZ is 4.9°N, 4.2°, and 11 mm/day, respectively, while for the double ITCZ, it is 0.4°N, 2.6°, 10.3 mm/day, respectively. While the SST anomalies in the Pacific Ocean (El Niño and La Niña episodes) affect more the ITCZ width, the SST anomalies in the Tropical South Atlantic affect both its position and width.

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“…The Intertropical Convergence Zone (ITCZ) is a large-scale atmospheric system originating from the ascending branch of the Hadley cell [1] . It manifests near the equator in various atmospheric fields as a band of trade wind convergence, minimum in atmospheric pressure, minimum in outgoing longwave radiation (OLR), deep convective clouds, and frequent intermittent rain events that transfer freshwater from the atmosphere to the ocean [2][3][4][5][6][7][8][9][10][11] . These characteristics do not necessarily occur simultaneously and/ or in the same location [7,12] .…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Intertropical Convergence Zone over the Atlantic Ocean through an Algorithm Based on Precipitation

Chrysostomo de Oliveira Nogueira,

Gomes Machado,

Simões Reboita

et al. 2024

j. of atmos. sci. res.

0

View full text Add to dashboard Cite

The Intertropical Convergence Zone (ITCZ) is a key atmospheric system on a global scale, primarily driven by trade wind convergence near the equator. The ITCZ plays a crucial role in modulating the climate of the borders of tropical continental areas. For instance, Northeastern Brazil experiences a climate influenced by the ITCZ over the Atlantic Ocean. In some periods, the ITCZ exhibits double bands, known as the double ITCZ. While the features of the ITCZ have been described using various approaches and atmospheric variables, there is still a lack of regional studies focusing on the ITCZ and double ITCZ in the Atlantic Ocean. In this context, the main goals of this study are (1) to describe a simple algorithm based on precipitation to identify the ITCZ and double ITCZ, (2) to present a climatology (1997–2022) of the position, width, and intensity of these two convective bands, and (3) to investigate variabilities in the ITCZ characteristics associated with anomalies of sea surface temperature (SST) in the tropical Pacific and Atlantic oceans. The double ITCZ typically occurs southward of the main cloud band, and between February and April, both bands are more distant (~4.5°). In the western sector of the Atlantic Ocean, the ITCZ and its double band extend to more southerly latitudes in austral autumn. Considering the entire Atlantic basin, the annual mean of the latitudinal position, width, and intensity of the ITCZ is 4.9°N, 4.2°, and 11 mm/day, respectively, while for the double ITCZ, it is 0.4°N, 2.6°, 10.3 mm/day, respectively. While the SST anomalies in the Pacific Ocean (El Niño and La Niña episodes) affect more the ITCZ width, the SST anomalies in the Tropical South Atlantic affect both its position and width.

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The inner life of the Atlantic Intertropical Convergence Zone

Cited by 4 publications

References 53 publications

Response of the global ITCZ to different ENSO phases and how the ITCZ determined from the maximum precipitation compares with the surface tropical winds convergence

Response of the global ITCZ to different ENSO phases and how the ITCZ determined from the maximum precipitation compares with the surface tropical winds convergence

Assessment of the Intertropical Convergence Zone over the Atlantic Ocean through an Algorithm Based on Precipitation

Assessment of the Intertropical Convergence Zone over the Atlantic Ocean through an Algorithm Based on Precipitation

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