IPCC global coupled model simulations of the South America monsoon system

Abstract The South American monsoon system (SAMS) is the most important climatic feature in South America. This study focuses on the large-scale characteristics of the SAMS: seasonal amplitudes, onset and demise dates, and durations. Changes in the SAMS are investigated with the gridded precipitation, Climate Forecast System Reanalysis (CFSR), and the fifth phase of the Coupled Model Intercomparison Project (CMIP5) simulations for two scenarios [“historical” and high-emission representative concentration pathways (rcp8.5)]. Qualitative comparisons with a previous study indicate that some CMIP5 models have significantly improved their representation of the SAMS relative to their CMIP3 versions. Some models exhibit persistent deficiencies in simulating the SAMS. CMIP5 model simulations for the historical experiment show signals of climate change in South America. While the observational data show trends, the period used is too short for final conclusions concerning climate change. Future changes in the SAMS are analyzed with six CMIP5 model simulations of the rcp8.5 high-emission scenario. Most of the simulations show significant increases in seasonal amplitudes, early onsets, late demises, and durations of the SAMS. The simulations for this scenario project a 30% increase in the amplitude from the current level by 2045–50. In addition, the rcp8.5 scenario projects an ensemble mean decrease of 14 days in the onset and 17-day increase in the demise date of the SAMS by 2045–50. The results additionally indicate lack of spatial agreement in model projections of changes in total wet-season precipitation over South America during 2070–2100. The most consistent CMIP5 projections analyzed here are the increase in the total monsoon precipitation over southern Brazil, Uruguay, and northern Argentina.

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Global horizontal irradiation: spatio-temporal variability on a regional scale in the south of the Pampeana region (Argentina)

AUC GEOGRAPHICA ◽

10.14712/23361980.2021.14 ◽

2021 ◽

Vol 56 (2) ◽

pp. 220-233

Author(s):

María Eugenia Fernández ◽

Jorge Osvaldo Gentili ◽

Ana Casado ◽

Alicia María Campo

Keyword(s):

South America ◽

Seasonal Dynamics ◽

Temporal Variability ◽

Cloud Cover ◽

Regional Scale ◽

Temporal Distribution ◽

The South ◽

Monsoon System ◽

Spatio Temporal ◽

Dynamics Of Action

The objective of this work is to analyze the spatio-temporal distribution of Global Horizontal Irradiation (GHI) on a regional scale and its relationship with frequent synoptic situations in the south of the Pampeana region (Argentina). It was verified that the latitudinal pattern of distribution of the GHI is modified in the region by cloud cover, which is in turn determined by the seasonal dynamics of action centers and the passage of fronts in summer and winter. The South America Monsoon System (SAMS) defines differential situations of cloudiness and rainfall in the region, which affect GHI. GHI increased successively between the decades 1981–2010, a factor associated with the variability of rainfall that characterizes the region.

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Late Quaternary Variations in the South American Monsoon System as Inferred by Speleothems—New Perspectives using the SISAL Database

Quaternary ◽

10.3390/quat2010006 ◽

2019 ◽

Vol 2 (1) ◽

pp. 6 ◽

Cited By ~ 10

Author(s):

Michael Deininger ◽

Brittany Marie Ward ◽

Valdir F. Novello ◽

Francisco W. Cruz

Keyword(s):

South America ◽

Late Quaternary ◽

Precipitation Amount ◽

Ice Age ◽

Convergence Zone ◽

South American ◽

The South ◽

South American Monsoon ◽

Monsoon System ◽

South American Monsoon System

Here we present an overview of speleothem δ18O records from South America, most of which are available in the Speleothem Isotopes Synthesis and Analysis (SISAL_v1) database. South American tropical and subtropical speleothem δ18O time series are primarily interpreted to reflect changes in precipitation amount, the amount effect, and consequently history of convection intensity variability of convergence zones such as the Intertropical Convergence Zone (ITCZ) and the South America Monsoon System (SAMS). We investigate past hydroclimate scenarios in South America related to the South American Monsoon System in three different time periods: Late Pleistocene, Holocene, and the last two millennia. Precession driven summertime insolation is the main driver of convective variability over the continent during the last 120 kyrs (from present day to 120 kyrs BP), including the Holocene. However, there is a dipole between speleothem δ18O records from western and eastern South America. Records located in the central region of Brazil are weakly affected by insolation-driven variability, and instead are more susceptible to the variability associated with the South Atlantic Convergence Zone (SACZ). Cold episodic events in the Northern Hemisphere, such as Heinrich and Bond Events, and the Little Ice Age, increase the convective activity of the SAMS, resulting in increased precipitation amount in South America.

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Daily Precipitation Statistics for South America: An Intercomparison between NCEP Reanalyses and Observations

Journal of Hydrometeorology ◽

10.1175/2010jhm1303.1 ◽

2011 ◽

Vol 12 (1) ◽

pp. 101-117 ◽

Cited By ~ 33

Author(s):

Viviane B. S. Silva ◽

Vernon E. Kousky ◽

R. Wayne Higgins

Keyword(s):

South America ◽

Large Scale ◽

Atmospheric Model ◽

Northeastern Brazil ◽

South American ◽

The South ◽

Wet Season ◽

Central Brazil ◽

Monsoon System ◽

Dry Bias

Abstract In this study, the authors document the extent to which the precipitation statistics of the new CFS reanalysis (CFSR) represent an improvement over the earlier reanalyses: the NCEP–NCAR reanalysis (R1) and the NCEP–DOE Second Atmospheric Model Intercomparison Project (AMIP-II) reanalysis (R2). An intercomparison between the CFSR, R1, R2, and observations over South America was made for the period 1979–2006. The CFSR shows notable improvements in the large-scale precipitation patterns compared with the previous reanalyses (R1 and R2). In spite of these improvements, the CFSR has substantial biases in intensity and frequency of occurrence of rainfall events. Over west-central Brazil, the core region of the South American monsoon system (SAMS), the CFSR displays a dry bias during the onset phase of the SAMS wet season and a wet bias during the peak and decay phases of the SAMS wet season. The CFSR also displays a dry bias along the South American coast near the mouth of the Amazon and along the east coast of northeastern Brazil. A wet bias exists in all seasons over southeast Brazil and over the Andes Mountains.

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Precipitation Characteristics of the South American Monsoon System Derived from Multiple Datasets

Journal of Climate ◽

10.1175/jcli-d-11-00335.1 ◽

2012 ◽

Vol 25 (13) ◽

pp. 4600-4620 ◽

Cited By ~ 33

Author(s):

Leila M. V. Carvalho ◽

Charles Jones ◽

Adolfo N. D. Posadas ◽

Roberto Quiroz ◽

Bodo Bookhagen ◽

...

Keyword(s):

South America ◽

Large Scale ◽

Austral Summer ◽

Global Precipitation Climatology Project ◽

South American ◽

The South ◽

Frequency Distributions ◽

South American Monsoon ◽

Monsoon System ◽

South American Monsoon System

Abstract The South American monsoon system (SAMS) is the most important climatic feature in South America and is characterized by pronounced seasonality in precipitation during the austral summer. This study compares several statistical properties of daily gridded precipitation from different data (1998–2008): 1) Physical Sciences Division (PSD), Earth System Research Laboratory [1.0° and 2.5° latitude (lat)/longitude (lon)]; 2) Global Precipitation Climatology Project (GPCP; 1° lat/lon); 3) Climate Prediction Center (CPC) unified gauge (CPC-uni) (0.5° lat/lon); 4) NCEP Climate Forecast System Reanalysis (CFSR) (0.5° lat/lon); 5) NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis (0.5° lat/0.3° lon); and 6) Tropical Rainfall Measuring Mission (TRMM) 3B42 V6 data (0.25° lat/lon). The same statistical analyses are applied to data in 1) a common 2.5° lat/lon grid and 2) in the original resolutions of the datasets. All datasets consistently represent the large-scale patterns of the SAMS. The onset, demise, and duration of SAMS are consistent among PSD, GPCP, CPC-uni, and TRMM datasets, whereas CFSR and MERRA seem to have problems in capturing the correct timing of SAMS. Spectral analyses show that intraseasonal variance is somewhat similar in the six datasets. Moreover, differences in spatial patterns of mean precipitation are small among PSD, GPCP, CPC-uni, and TRMM data, while some discrepancies are found in CFSR and MERRA relative to the other datasets. Fitting of gamma frequency distributions to daily precipitation shows differences in the parameters that characterize the shape, scale, and tails of the frequency distributions. This suggests that significant uncertainties exist in the characterization of extreme precipitation, an issue that is highly important in the context of climate variability and change in South America.

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Moisture transport and intraseasonal variability in the South America monsoon system

Climate Dynamics ◽

10.1007/s00382-010-0806-2 ◽

2010 ◽

Vol 36 (9-10) ◽

pp. 1865-1880 ◽

Cited By ~ 52

Author(s):

Leila M. V. Carvalho ◽

Ana E. Silva ◽

Charles Jones ◽

Brant Liebmann ◽

Pedro L. Silva Dias ◽

...

Keyword(s):

South America ◽

Moisture Transport ◽

Intraseasonal Variability ◽

The South ◽

Monsoon System

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Late Quaternary Variations in the South American Monsoon System as Inferred by Speleothems – New Perspectives Using the SISAL Database

10.20944/preprints201810.0094.v1 ◽

2018 ◽

Author(s):

Michael Deininger ◽

Brittany Marie Ward ◽

Valdir F. Novello ◽

Francisco W. Cruz

Keyword(s):

South America ◽

Time Scales ◽

Late Pleistocene ◽

Convergence Zone ◽

South American ◽

The South ◽

The Holocene ◽

South American Monsoon ◽

Monsoon System ◽

South American Monsoon System

Here we present an overview of speleothem δ18O records from South America, which mostly are available in the Speleothem Isotopes Synthesis and Analysis (SISAL_v1) database. South American tropical and subtropical δ18O time series are primarily interpreted as being driven by the amount effect and, consequently show the past history of the convection intensity of convergence zones such as the Intertropical Convergence Zone and the South America Monsoon System. We investigate past hydroclimate scenarios in South America related to the South American Monsoon System in three different time scales: Late Pleistocene, Holocene and the last two millennia. The precession driven insolation is the main driver of convective variability over the continent during the last 250 kyrs, including the Holocene period. However a dipole is observed between the west and east portions of the continent. Records located in the central region of Brazil appear to be weakly affected by insolation driven variability and more susceptible to the South Atlantic Convergence Zone. Cold episodic events in Northern Hemisphere increase the activity of the South American Monsoon System on all time scales, in turn increasing rainfall amounts in South America, as was documented during Heinrich events in the late Pleistocene and Bond events in the Holocene, as well as during the Little Ice Age.

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Review of: El Niño influence over South America during the mid-holocene

Advances in Geosciences ◽

10.5194/adgeo-6-279-2006 ◽

2006 ◽

Vol 6 ◽

pp. 279-282 ◽

Cited By ~ 2

Author(s):

T. Jorgetti ◽

P. L. Silva Dias ◽

P. Braconnot

Keyword(s):

Spatial Distribution ◽

South America ◽

Coupled Model ◽

Sea Surface ◽

Before Present ◽

Present Climate ◽

Model Simulations ◽

The Pacific ◽

The Pacific Ocean ◽

The Relationship

Abstract. This work reports on the relationship between the Pacific Ocean sea surface temperature variability and precipitation over South America in the IPSL coupled model simulations of the present and the 6 kyr Before Present (Mid-Holocene) climate. The model results suggests that the control exerted by ENSO on precipitation in South America was less frequent in the Mid-Holocene compared to the present climate and that the spatial distribution of the ENSO influence is considerably different in the two periods.

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Analysis of CMIP 5 simulations of key climate indices associated with the South America monsoon system

International Journal of Climatology ◽

10.1002/joc.6627 ◽

2020 ◽

Vol 41 (1) ◽

pp. 404-422 ◽

Cited By ~ 1

Author(s):

Vanesa Londoño Arteaga ◽

Carlos Henrique Ribeiro Lima

Keyword(s):

South America ◽

Climate Indices ◽

The South ◽

Monsoon System

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The South American monsoon variability over the last millennium in climate models

Climate of the Past ◽

10.5194/cp-12-1681-2016 ◽

2016 ◽

Vol 12 (8) ◽

pp. 1681-1691 ◽

Cited By ~ 13

Author(s):

Maisa Rojas ◽

Paola A. Arias ◽

Valentina Flores-Aqueveque ◽

Anji Seth ◽

Mathias Vuille

Keyword(s):

South America ◽

Large Scale ◽

Model Simulation ◽

Ice Age ◽

South American ◽

Last Millennium ◽

The South ◽

Model Simulations ◽

South American Monsoon ◽

The Past

Abstract. In this paper we assess South American monsoon system (SAMS) variability in the last millennium as depicted by global coupled climate model simulations. High-resolution proxy records for the South American monsoon over this period show a coherent regional picture of a weak monsoon during the Medieval Climate Anomaly and a stronger monsoon during the Little Ice Age (LIA). Due to the small external forcing during the past 1000 years, model simulations do not show very strong temperature anomalies over these two specific periods, which in turn do not translate into clear precipitation anomalies, in contrast with the rainfall reconstructions in South America. Therefore, we used an ad hoc definition of these two periods for each model simulation in order to account for model-specific signals. Thereby, several coherent large-scale atmospheric circulation anomalies are identified. The models feature a stronger monsoon during the LIA associated with (i) an enhancement of the rising motion in the SAMS domain in austral summer; (ii) a stronger monsoon-related upper-tropospheric anticyclone; (iii) activation of the South American dipole, which results in a poleward shift of the South Atlantic Convergence Zone; and (iv) a weaker upper-level subtropical jet over South America. The diagnosed changes provide important insights into the mechanisms of these climate anomalies over South America during the past millennium.

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