The role of Amazon Basin moisture on the atmospheric branch of the hydrological cycle: a Lagrangian analysis

Drumond, Anita; Marengo, José; Ambrizzi, Tércio; Nieto, Raquel; Moreira, Lorena; Gimeno, Luis

doi:10.5194/hessd-11-1023-2014

Cited by 48 publications

(64 citation statements)

References 55 publications

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“…Data obtained from ECMWF reanalysis ERA‐Interim (Dee et al , ), on a 1.5° × 1.5° grid, for the period March to November 1982–2009, were used to plot both the flux and its divergence anomalies for the periods of the extreme dry events for each homogeneous region. The Eulerian approach focuses on specific regions in space through which the fluid flows in time, so it is not possible to extract the link between the precipitation over a region and the moisture source (Gimeno et al , ; Drumond et al , ).…”

Section: Methodsmentioning

confidence: 99%

Anomalous patterns of SST and moisture sources in the South Atlantic Ocean associated with dry events in southeastern Brazil

Pampuch

Drumond

Gimeno

et al. 2016

Intl Journal of Climatology

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This paper examines the distributions of anomalies of sea surface temperature (SST) and of the moisture sources in the South Atlantic Ocean during extreme dry events in southeastern Brazil in the austral autumn, winter and spring for the period 1982-2009. The extreme dry events were identified based on a combination in which consecutive dry days and variable percentiles were considered in five homogeneous regions in terms of precipitation in southeastern Brazil, as defined through cluster analysis. Composites of anomalies of SST and moisture sources for the dry events selected for the different homogeneous regions show specific characteristics for each region, but some similarities were apparent for the southern and northern parts of southeast Brazil. During spring in all regions, and during autumn and winter in the southern regions, a tripole pattern of SST anomalies was found (negative, positive and negative), together with an anomalous anticyclonic circulation in the Atlantic Ocean transporting moisture to southern Brazil associated with positive SST anomalies. A decrease in the climatological moisture sources in the south of Brazil then ensues, and dry conditions prevail in the regions of interest. In winter and autumn in the northern regions, the same tripole pattern of SST anomalies was also found, but shifted northwards. An anomalous cyclone is associated with the negative SST anomalies, and the climatological moisture sources to the northeast of Brazil reduce their contribution to the region of interest, where negative precipitation anomalies are registered. It seems that the events selected show the results of reductions both in terms of the availability of moisture and in atmospheric instability.

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Section: Methodsmentioning

confidence: 99%

Anomalous patterns of SST and moisture sources in the South Atlantic Ocean associated with dry events in southeastern Brazil

Pampuch

Drumond

Gimeno

et al. 2016

Intl Journal of Climatology

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“…In addition, moisture flux stream function (ψ Q )/potential (X Q ) and its non-divergent/divergent components are also used to diagnose precipitation changes. In addition, the moisture source for the Amazon basin is mainly from the North Atlantic in both wet and dry seasons (Satyamurty et al, 2013a(Satyamurty et al, , 2013bDrumond et al, 2014). The moisture transport from the North Atlantic is also used to diagnose precipitation change in this study.…”

Section: Physical Mechanismsmentioning

confidence: 99%

Impacts of the Pacific Meridional Mode on June–August precipitation in the Amazon River Basin

Zhang

Villarini

Vecchi

2017

Quart J Royal Meteoro Soc

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This study examines the impacts of the Pacific Meridional Mode (PMM) on Amazon precipitation during June–August using observations and several experiments with the National Oceanic and Atmospheric Administration/Geophysical Fluid Dynamics Laboratory (NOAA/GFDL) Forecast‐oriented Low Ocean Resolution version of CM2.5 (FLOR). We find that the positive (negative) PMM can lead to precipitation surplus (deficit) using both observations and climate simulations with FLOR. The impacts of PMM on Amazon precipitation during June–August are induced by the forcing of sea‐surface temperature (SST) anomalies associated with PMM. Positive PMM can force the baroclinic Gill responses to the heat source in the Pacific with two low‐level cyclones (anticyclones) located west (east) of the heating source. The anomalous low‐level anticyclone and high‐level cyclone located in the Amazon region are associated with low‐level moisture transport from the Atlantic. There is significant positive correlation between the PMM index and moisture flux convergence in most parts of the Amazon basin, with negative correlation in its northwestern part. Such physical mechanisms underlying the linkage between PMM and the Amazon precipitation are supported by both the 500 years control experiment and a suite of perturbation experiments with FLOR.

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“…However, such results of perfect closure are highly influenced by the methodologies employed when estimating evapotranspiration, with estimations that are mostly based on the precipitation product used in the closure calculations providing results that are not completely accurate due to dependence between data sets. The imbalance of the surface water budget found in the Amazon River basin (Marengo, ) has previously been addressed by other authors as a misrepresentation of the biological fluxes over the basin that may in turn affect the estimation of evapotranspiration (Drumond et al, ; Jasechko et al, ; Makarieva et al, ).…”

Section: Introductionmentioning

confidence: 99%

Conjoint Analysis of Surface and Atmospheric Water Balances in the Andes‐Amazon System

Builes‐Jaramillo

Poveda

2018

Water Resources Research

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Surface and atmospheric water balances analysis for Amazon River basin at monthly time scale are performed with an emphasis on the linkages between the Andes and low-lying Amazonia. Analyses are performed using observational and reanalysis data covering five different periods of analysis (depending on length of evapotranspiration data sets) for the entire basin, major subcatchments, and for the Andes and low-lying Amazonia. Results for the entire basin show a state close to balance within tolerance, while the spatial disaggregation produced a less clear picture, presenting major discrepancies between observations and reanalysis data sets. The atmospheric budget exhibits no closure and positive residuals regardless of data set, with the magnitude of residuals for the entire Amazon basin highly dependent on evapotranspiration data source. The imbalance between the two water budgets (14%-16%) is driven by higher values of runoff and by an abrupt change in runoff when changing from dry to wet seasons in the Amazon. We unveil two shortcomings of the available data, namely poor quality in the representation of surface processes by reanalysis, and flaws and scarcity of information in the high Andes that induce uncertainties and errors in both water budgets. The results of the present study highlight the importance of the Andean region for the hydrological integrity of the entire Amazon River basin. Our results confirm the paramount importance of the joint analysis of atmospheric and surface water budgets at the basin level with respect to achieving a complete understanding of the whole hydrological cycle at the continental scale.

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The role of Amazon Basin moisture on the atmospheric branch of the hydrological cycle: a Lagrangian analysis

Cited by 48 publications

References 55 publications

Anomalous patterns of SST and moisture sources in the South Atlantic Ocean associated with dry events in southeastern Brazil

Anomalous patterns of SST and moisture sources in the South Atlantic Ocean associated with dry events in southeastern Brazil

Impacts of the Pacific Meridional Mode on June–August precipitation in the Amazon River Basin

Conjoint Analysis of Surface and Atmospheric Water Balances in the Andes‐Amazon System

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