Pacific and Atlantic multidecadal variability relations to the El Niño events and their effects on the South American rainfall

Kayano, Mary Toshie; Andreoli, Rita V.; Souza, Rodrigo Augusto Ferreira de

doi:10.1002/joc.6326

Cited by 38 publications

(43 citation statements)

References 55 publications

(105 reference statements)

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“…The years with zonal wind above the 50th percentile in the periods before and after 1997 are listed in Table 1 and represented by the dark gray bars in Figure 2. 1988-1989-1990-1993-1994-1995-1996After 1999-2003-2005-2007-2008-2010-2011 In addition, the periods before and after 1997 overlap those with distinct low-frequency SST backgrounds associated with the PDO and the AMO previously discussed by Kayano et al [40,79]. In fact, SST anomaly mean state during the 1983-1996 period shows features of the CAMO/WPDO and that during 1998-2016, of the WAMO/CPDO background (Figure 3a,b).…”

Section: Changes In Zonal Wind Indexmentioning

confidence: 82%

“…The 1983-1996 and 1998-2016 periods overlap the periods when the Atlantic Multi-decadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) are in the cold AMO and warm PDO (CAMO/WPDO), and in the warm AMO and cold PDO (WAMO/CPDO), respectively. Kayano et al [40,79] showed that these SST anomaly backgrounds affect the El Niño-Southern Oscillation (ENSO) related rainfall anomalies in South America (SA) through low-frequency changes in the Walker cell. These changes in the Walker cell have been previously documented with an intensification during the last three decades [41,84].…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the SST data for the 1870-2016 period were used here to construct the SON SST anomaly mean states for the periods before and after the breakpoint. In this case, as proposed by Kayano et al [40,79], the linear trend of the 1870-2016 time series at each grid point was removed to eliminate the effects of climate change. The standardized monthly anomalies for the period 1983-2016 in the domain limited at 60 • N, 60 • S, 120 • E and the Greenwich longitude were obtained.…”

Section: Methodsmentioning

confidence: 99%

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The Influence of the Atlantic Multidecadal Oscillation on the Choco Low-Level Jet and Precipitation in Colombia

et al. 2020

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This study examines the influence of the Atlantic Multidecadal Oscillation (AMO) on the Choco Low-level Jet (CJ) variations during the 1983–2016 period. Considering the September–November (SON) 925 hPa zonal wind index in the CJ core, a significant breakpoint occurs in 1997 with larger values after 1997. The changes in the CJ and Caribbean Low-Level Jet (CLLJ), and their related ocean-atmospheric patterns and impacts on precipitation over Colombia were analyzed considering separately the 1983–1996 and 1998–2016 periods, which overlap the cold and warm AMO phases, respectively. During the 1998–2016 period, the negative sea surface temperature (SST) anomalies in the tropical Pacific Ocean and the positive ones in the Caribbean Sea and Tropical North Atlantic (TNA) strengthen the CJ and weaken the CLLJ, and moisture is transported into Central and Western Colombia increasing the rainfall there. Our results indicate that part of the CJ strengthening after 1997 was due to a higher percentage of intense CJ events coinciding with La Niña events during the warm AMO and cold Pacific Decadal Oscillation (PDO) background. However, the AMO-related SST and sea level pressure (SLP) variations in the TNA seem to be more crucial in modulating the CJ and CLLJ intensities, such that CJ is weakened (intensified) and CLLJ is intensified (weakened) before (after) 1997. As far as we know, the relations of the CJ and CLLJ intensities to the AMO phases were not examined before and might be useful for modeling studies.

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Section: Changes In Zonal Wind Indexmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The Influence of the Atlantic Multidecadal Oscillation on the Choco Low-Level Jet and Precipitation in Colombia

et al. 2020

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“…Our findings show that the Atlantic Ocean plays an important role in modulating the rainfall and streamflow variability in the ARB. At the low frequency time scale, the SST and SLP anomalies in this Oceanic sector create the east-west SST and SLP gradients between the tropical Atlantic and eastern Pacific Oceans, which during the WAMO phase favors the La Niña event establishment [77]. Physical explanation is that the changes in the tropical Atlantic SST modify the inter-basin (tropical Atlantic and tropical eastern Pacific) pressure gradient, creating an atmospheric bridge that transmits the SST information between the basins [94,105].…”

Section: Discussionmentioning

confidence: 99%

“…Following the methodology proposed by Kayano et al [76,77], the reconstructed SST data of the 1870-2015 period were used only to support that the SST anomaly patterns during the 1965-1994 and 1995-2015 periods indeed contain, respectively, the CAMO and WAMO features [35,78]. In order to remove the climate change effects, the linear trend for the 1870-2015 of the time series at each grid point was eliminated using the method of least squares.…”

Section: Mean Sst Anomaly Patterns During the Amo Phasesmentioning

confidence: 99%

Streamflow Intensification Driven by the Atlantic Multidecadal Oscillation (AMO) in the Atrato River Basin, Northwestern Colombia

Cerón

Kayano

Andreoli

et al. 2020

Water

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The impact of the Atlantic Multidecadal Oscillation (AMO) on the variations in the streamflow in the Atrato River Basin (ARB) during the 1965–2016 period was analyzed here by considering the cold (1965–1994) and warm (1995–2015) phases of this oscillation. The mean streamflow increased after 1994 (AMO phase change). This increase is related to the strengthening of the zonal gradients of the sea surface temperature (SST) and sea level pressure (SLP) between the tropical central Pacific and the tropical Atlantic after 1994 (warm AMO phase). These gradients contributed to strengthen the Walker cell related upward movement over northern and northwestern South America, in particular during November-December (ND). Consistently, the frequency (R20 mm) and intensity (SDII) of extreme daily rainfall events increased during the 1995–2015 period. Our results show a connection between the AMO and the increase in the streamflow in the ARB during the last five decades. These results contribute to the studies of resilience and climate adaptation in the region.

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Rainfall variability in Brazil between 1920 and 2010

Peres

Maier

2022

Intl Journal of Climatology

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Precipitation variability in Brazil was investigated using reanalysis data from the Global Historical Climatology Network-Monthly, version 3.01, within 1920-2010, provided freely by the University of Delaware. The analysis of space-temporal pattern was conducted using principal component analysis (PCA) in temporal and spatial modes. It also intends to contribute with the literature that characterizes the patterns of spatiotemporal distribution of precipitation in Brazil. Temporal grouping allowed the identification of five spatial models that represents the spatial distribution of the precipitation, explained variance of 38%. Spatial grouping mode zoned through six temporal models of the areas with partially homogeneous precipitation, explained variance of 22.69%. In equatorial latitudes, the models identified Intertropical Convergence Zone (ITCZ) latitudinal and temporal variability in North and South Hemispheres. In tropical latitudes, the models evidenced anomalous precipitation due to South Atlantic Convergence Zone (SACZ) and South America Monsoon System. In subtropical latitudes, rainfall spatial anomalous patterns were associated to the di-pole pattern between tropical and subtropical latitudes, which shows the influence of the climatic variability modes, especially El Niño-Southern Oscillation (ENSO). Therefore, it was diagnosed that the anomalies of the atmospheric mechanisms that occur seasonally, such as SACZ and ITCZ, are the ones that cause the higher frequency in the percentage of rainfall variance, which might be explained by the frequency of the occurrence. However, remote factors, such as the occurrence in different temporal scales, interannual and interdecennial, were represented in different spatial and temporal models, as the events of variability modes vary spatially, seasonally and in intensity. It is important to highlight that the modes of climatic variability may influence the atmospheric mechanisms identified in this study, nevertheless, their impact were not evidenced in the space-temporal scales analysed. The results are relevant to understand the space-temporal variability of rainfall over Brazil.

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Pacific and Atlantic multidecadal variability relations to the El Niño events and their effects on the South American rainfall

Cited by 38 publications

References 55 publications

The Influence of the Atlantic Multidecadal Oscillation on the Choco Low-Level Jet and Precipitation in Colombia

The Influence of the Atlantic Multidecadal Oscillation on the Choco Low-Level Jet and Precipitation in Colombia

Streamflow Intensification Driven by the Atlantic Multidecadal Oscillation (AMO) in the Atrato River Basin, Northwestern Colombia

Rainfall variability in Brazil between 1920 and 2010

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