Calibration and combination of seasonal precipitation forecasts over South America using Ensemble Regression

2021 ◽  
Author(s):  
Marisol Osman ◽  
Caio A. S. Coelho ◽  
Carolina S. Vera
Keyword(s):  
South America ◽  
Seasonal Precipitation ◽  
Ensemble Regression

An analysis of the seasonal precipitation forecasts in South America using wavelets

2009 ◽  
Vol 29 (11) ◽  
pp. 1560-1573 ◽  
Author(s):  
Luciano Ponzi Pezzi ◽  
Mary Toshie Kayano
Keyword(s):  
South America ◽  
Seasonal Precipitation

scholarly journals Supplemental Material: Isotope sclerochronology indicates enhanced seasonal precipitation in northern South America (Colombia) during the Mid-Miocene Climatic Optimum

2020 ◽  
Author(s):  
S.R. Scholz
Keyword(s):  
South America ◽  
Seasonal Precipitation ◽  
Isotopic Data ◽  
Northern South America ◽  
Climatic Optimum

Supplemental figures, tables, and methods discussed in the text, as well as a separate MSExcel file containing all raw isotopic data.<br>

Tropical Cyclone and Easterly Wave Relationship in Regional Precipitation over the Tropical and Subtropical North America

2021 ◽  
Author(s):  
Christian Dominguez
Keyword(s):  
North America ◽  
South America ◽  
Negative Impact ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Seasonal Rainfall ◽  
Seasonal Precipitation ◽  
Tropical Eastern Pacific ◽  
Threshold Distance ◽  
Northern South America

&lt;p&gt;Tropical cyclones (TCs) and easterly waves (EWs) produce significant seasonal rainfall over the tropical and subtropical North America. When TC activity over the tropical eastern Pacific (TEP) or the Intra Americas Seas (IAS) is below-normal (above-normal), regional precipitation may be below (above-normal). However, it is not only the number of TCs what may change seasonal precipitation, but the trajectory of the systems. TCs induce intense precipitation over continental regions if they are close enough to shorelines, for instance, if the TC center is located less than 500 km-distant from the coast. However, if TCs are more remote than this threshold distance, the chances of rain over continental regions decrease, particularly in arid and semi-arid regions. In addition, a distant TC may induce subsidence or produce moisture divergence that inhibits, at least for a few days, convective activity farther away than the threshold distance.&lt;/p&gt;&lt;p&gt;EWs can produce up to 50% of seasonal rainfall and contribute substantially to interannual regional rainfall variability. An observational analysis shows that the El Ni&amp;#241;o Southern Oscillation (ENSO) affects EW frequency and therefore, their contribution to seasonal rainfall. In recent years, TC activity over the Main Development Region (MDR) of the tropical North Atlantic has a negative impact on regional seasonal precipitation over northern South America. High TC activity over MDR corresponds to below-normal precipitation because it reduces the EW activity reaching northern South America through the recurving of TC tracks. Recurving TC tracks redirect moisture away from the tropical belt and into the mid-latitudes. However, this relationship only holds under neutral ENSO conditions and the positive phase of the Atlantic Multidecadal Oscillation. A 10-member regional model multi-physics ensemble simulation for the period 1990&amp;#8211;2000 was analyzed to show the relationships are robust to different representations of physical processes. This new understanding of seasonal rainfall over the tropical Americas may support improved regional seasonal and climate outlooks.&lt;/p&gt;

scholarly journals Eastern Patagonia Seasonal Precipitation: Influence of Southern Hemisphere Circulation and Links with Subtropical South American Precipitation

2012 ◽  
Vol 25 (19) ◽  
pp. 6781-6795 ◽  
Author(s):  
Ana Laura Berman ◽  
Gabriel Silvestri ◽  
Rosa Compagnucci
Keyword(s):  
South America ◽  
Atmospheric Circulation ◽  
Southern Hemisphere ◽  
South American ◽  
Seasonal Precipitation ◽  
The Andes ◽  
Four Seasons ◽  
Westerly Flow ◽  
Continental Area ◽  
Frontal Systems

Abstract Some aspects of the seasonal precipitation over eastern Patagonia, the southernmost area of South America east of the Andes Cordillera, are examined in this paper. Results indicate that the central-north areas, the southern continental region, and the southernmost islands are three independent regions of seasonal precipitation, and that each of them is associated with specific patterns of atmospheric circulation. Precipitation over the central-north region is significantly related to the precipitation over a wide area of southern South America east of the Andes during the four seasons. Enhanced (reduced) precipitation over this area is associated with weakened (intensified) westerly flow in the region. Precipitation over the southern continental area has a close connection with the dipolar pattern of precipitation over subtropical South America during spring, summer, and autumn. The anomalies of atmospheric circulation at low and upper levels associated with the subtropical dipole are also able to modulate the intensity of the westerlies over the south of eastern Patagonia, affecting the regional precipitation. Precipitation over the islands of the southernmost part of eastern Patagonia is connected with subtropical precipitation in summer and winter. The activity of frontal systems associated with migratory perturbations moving to the east along the Southern Hemisphere storm tracks modulates the variability of seasonal precipitation over this region.

scholarly journals Easterly wave contributions to seasonal rainfall over the tropical Americas in observations and a regional climate model

2019 ◽  
Vol 54 (1-2) ◽  
pp. 191-209 ◽  
Author(s):  
Christian Dominguez ◽  
James M. Done ◽  
Cindy L. Bruyère
Keyword(s):  
South America ◽  
Climate Model ◽  
Negative Impact ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Rain Gauge ◽  
Regional Model ◽  
Seasonal Rainfall ◽  
Seasonal Precipitation ◽  
Northern South America

Abstract Easterly waves (EWs) are important moisture carriers and their variability can impact the total May–November rainfall, defined as seasonal precipitation, over the Tropical Americas. The contribution of EWs to the seasonal precipitation is explored over the tropical Americas using rain gauge stations, reanalysis data and a regional model ensemble during the 1980–2013 period. In the present study, EWs are found to produce up to 50% of seasonal rainfall mainly over the north of South America and contribute substantially to interannual regional rainfall variability. An observational analysis shows that the El Niño Southern Oscillation (ENSO) affects EW frequency and therefore, their contribution to seasonal rainfall. In recent years, tropical cyclone (TC) activity over the Main Development Region (MDR) of the tropical North Atlantic has a negative impact on regional seasonal precipitation over northern South America. High TC activity over MDR corresponds to below-normal precipitation because it reduces the EW activity reaching northern South America through the recurving of TC tracks. Recurving TC tracks redirect moisture away from the tropical belt and into the mid-latitudes. However, this relationship only holds under neutral ENSO conditions and the positive phase of the Atlantic Multidecadal Oscillation. A 10-member regional model multi-physics ensemble simulation for the period 1990–2000 was analyzed to show the relationships are robust to different representations of physical processes. This new understanding of seasonal rainfall over the tropical Americas may support improved regional seasonal and climate outlooks.

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