scholarly journals Moisture transport and intraseasonal variability in the South America monsoon system

2010 ◽  
Vol 36 (9-10) ◽  
pp. 1865-1880 ◽  
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

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

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.

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

Quaternary ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 6 ◽  
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.

scholarly journals IPCC global coupled model simulations of the South America monsoon system

2008 ◽  
Vol 33 (7-8) ◽  
pp. 893-916 ◽  
Author(s):  
Rodrigo J. Bombardi ◽  
Leila M. V. Carvalho
Keyword(s):  
South America ◽  
Coupled Model ◽  
The South ◽  
Model Simulations ◽  
Monsoon System ◽  
Global Coupled Model

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

2011 ◽  
Vol 12 (1) ◽  
pp. 101-117 ◽  
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.

Intraseasonal Variability Associated with Summer Precipitation over South America Simulated by 14 IPCC AR4 Coupled GCMs

2009 ◽  
Vol 137 (9) ◽  
pp. 2931-2954 ◽  
Author(s):  
Jia-Lin Lin ◽  
Toshiaki Shinoda ◽  
Brant Liebmann ◽  
Taotao Qian ◽  
Weiqing Han ◽  
...  
Keyword(s):  
South America ◽  
General Circulation ◽  
Intraseasonal Variability ◽  
Summer Precipitation ◽  
Climate Simulation ◽  
Convergence Zone ◽  
The South ◽  
Central Pacific ◽  
South Central ◽  
Northward Propagation

Abstract This study evaluates the intraseasonal variability associated with summer precipitation over South America in 14 coupled general circulation models (GCMs) participating in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Eight years of each model’s twentieth-century climate simulation are analyzed. Two dominant intraseasonal bands associated with summer precipitation over South America are focused on: the 40- and the 22-day band. The results show that in the southern summer (November–April), most of the models underestimate seasonal mean precipitation over central-east Brazil, northeast Brazil, and the South Atlantic convergence zone (SACZ), while the Atlantic intertropical convergence zone (ITCZ) is shifted southward of its observed position. Most of the models capture both the 40- and 22-day band around Uruguay, but with less frequent active episodes than observed. The models also tend to underestimate the total intraseasonal (10–90 day), the 40-, and the 22-day band variances. For the 40-day band, 10 of the 14 models simulate to some extent the 3-cell pattern around South America, and 6 models reproduce its teleconnection with precipitation in the south-central Pacific, but only 1 model simulates the teleconnection with the MJO in the equatorial Pacific, and only 3 models capture its northward propagation from 50° to 32°S. For the 7 models with three-dimensional data available, only 1 model reproduces well the deep baroclinic vertical structure of the 40-day band. For the 22-day band, only 6 of the 14 models capture its northward propagation from the SACZ to the Atlantic ITCZ. It is found that models with some form of moisture convective trigger tend to produce large variances for the intraseasonal bands.

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

2012 ◽  
Vol 25 (13) ◽  
pp. 4600-4620 ◽  
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.

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

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.

scholarly journals Intraseasonal Teleconnections between South America and South Africa

2015 ◽  
Vol 28 (23) ◽  
pp. 9489-9497 ◽  
Author(s):  
Alice M. Grimm ◽  
C. J. C. Reason
Keyword(s):  
South America ◽  
Southern Africa ◽  
Rainfall Variability ◽  
Intraseasonal Variability ◽  
Daily Rainfall ◽  
Summer Rainfall ◽  
South American ◽  
Climate Anomalies ◽  
Monsoon System ◽  
The Tropics

Abstract Teleconnection of climate anomalies between various parts of the tropics and extratropics is a well-established feature of the climate system. Building on previous work showing that a teleconnection exists between the South American monsoon system and interannual summer rainfall variability over southern Africa, this study considers intraseasonal variability over these landmasses. It is shown that strong teleconnections exist between South African daily rainfall and that over various areas of South America, with the latter leading by 4–5 days, for both winter and summer, involving regions with strong rainfall in these seasons. During the summer, the mechanisms involve both a modulation of the local Walker cell as well as extratropical Rossby wave trains. For winter, the latter mechanism is more important. While in summer tropical convective anomalies over South America play an important role, in winter the subtropics become more important. In both cases, these modulations lead to regional changes in circulation over southern Africa that are favorable for the dominant synoptic rainfall-producing weather systems such as cutoff lows and tropical extratropical cloud bands.

scholarly journals Climate Change in the South American Monsoon System: Present Climate and CMIP5 Projections

2013 ◽  
Vol 26 (17) ◽  
pp. 6660-6678 ◽  
Author(s):  
Charles Jones ◽  
Leila M. V. Carvalho
Keyword(s):  
Climate Change ◽  
South America ◽  
South American ◽  
Cmip5 Model ◽  
The South ◽  
Model Simulations ◽  
South American Monsoon ◽  
High Emission ◽  
Monsoon System ◽  
South American 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.

Sign in / Sign up

Export Citation Format

Share Document