Semi-humid: The Landscape of Central Brazil

Salgado, André Augusto Rodrigues; Assis, Wellington Lopes; Magalhães, Antônio Pereira; Carmo, Flávio Fonseca do; Sordi, Michael Vinícius de; Oliveira, Fábio Soares de

doi:10.1007/978-3-030-04333-9_6

Cited by 5 publications

(3 citation statements)

References 31 publications

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“…For example, the mountain ranges along the southeastern Brazilian coast have slow recessions (median of 139 days) due to exceptionally steep terrains and a higher number and connectivity of fractures (e.g., Neves & Morales, 2007; Vieira & Gramani, 2015). In contrast, the central Brazilian highlands have quicker flow recessions (median of 79 days) associated with landscapes dominated by plateaus with flat terrains (e.g., Salgado et al., 2019). Moreover, the recession model indicates a significant negative association between recession and soil sand content, although the causes are unclear.…”

Section: Resultsmentioning

confidence: 99%

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Regional Low Flow Hydrology: Model Development and Evaluation

Chagas,

Chaffe,

Blöschl

2024

Water Resources Research

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Low flows result from the interplay of climatic variability and catchment storage dynamics, but it is unclear which of these variables is more relevant for explaining low flow spatial patterns. Here, we develop a new conceptual model that integrates process‐based hydrological knowledge with statistics and test it for 1,400 Brazilian catchments. Through comparative hydrology, we isolate the low flow generating mechanisms and estimate their components using linear model trees. The model explains 58% of the spatial variance in 7‐day minimum annual flows (Qmin) based on climate and catchment characteristics. The primary Qmin controls depend on the spatial scale of analysis. Catchment characteristics govern Qmin up to the continental scale (107 km2), where their relative importance matches that of climate. At subcontinental scales, catchment characteristics are twice as important as climate in predicting Qmin, suggesting that low flows are governed by the catchment's capacity to attenuate the climatic variability through water storage. Geological properties are the most important catchment characteristics, particularly bedrock type, lithology and topographic slope, determining streamflow recession rates in the dry season. Soil properties, primarily soil class and depth, are half as important as geology. Climate impacts Qmin mainly through mean annual rainfall minus evaporation, representing the potential groundwater recharge, while dry‐season length has the lowest impact. These results hold mainly for highly seasonal and snow‐free climates. Low flow hydrology that combines statistics with process understanding offers a promising framework for understanding regional low flow generating mechanisms and could support other estimation models than that presented here.

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Section: Resultsmentioning

confidence: 99%

“…10.1029/2023WR035063 associated with landscapes dominated by plateaus with flat terrains (e.g., Salgado et al, 2019). Moreover, the recession model indicates a significant negative association between recession and soil sand content, although the causes are unclear.…”

Section: Water Resources Researchmentioning

confidence: 99%

Regional Low Flow Hydrology: Model Development and Evaluation

Chagas,

Chaffe,

Blöschl

2024

Water Resources Research

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“…The Cerrado biome is located in the Brazilian Central Plateau, with a land area of two million km 2 and covering 22% of Brazil (Oliveira and Marquis, 2002; Salgado et al ., 2019). The Cerrado ranges from open fields to dense forest formations and is the second largest biome in the country (Becerra et al ., 2009).…”

Section: Methodsmentioning

confidence: 99%

Influence of the El Niño–Southern Oscillation and the sypnotic systems on the rainfall variability over the Brazilian Cerrado via Climate Hazard Group InfraRed Precipitation with Station data

Filho

Júnior

Silva

et al. 2021

Intl Journal of Climatology

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The rainfall is essential to Brazil's hydrological cycle, agricultural development, and power generation, mainly Cerrado biome. Thus, the study assessed the influence of the El Niño–Southern Oscillation (ENSO) and synoptic systems on rainfall variability over the Brazilian Cerrado. To evaluate this variability, it used monthly rainfall data from the second version of the Climate Hazard Group InfraRed Precipitation with Station (CHIRPS) database (1981–2020), based on the annual densidrograms and thematic maps. In Annual terms, the average climatological was 1,417 mm·year−1. The highest precipitation values (>1,500 mm·year−1) occurred at the boundaries between Cerrado and Amazon, mainly in the states of the Maranhão, Mato Grosso, and Tocantins due to physiography (<500 m). The seasonal rainfall was more frequent in summer (on average, 48% of the annual total) distributed over the biome due to the South American monsoon system and South Atlantic convergence zone. The climatological dry period occurred between November and March (on average, 8% of the annual total) due to the Atmospheric Blocking called as Bolivia High that inhibit the passage of synoptic system transients in Central Brazil. In monthly terms, January (July) is the wetter month with 18% (drier month with 1%) of the annual total. The annual densidrograms appointed the following wetter (drier) years: 1985, 1989, and 2009 (1990, 1993, and 2012), influenced by ENSO events. The year 1985 appointed an increase of 19% in the mean annual rainfall, but in 1990 showed a reduction of 18% in climatology (1981–2020). In terms of seasonal anomalies, the summer of 1985 (1990) appointed an increase of 26% above (2.5% below) mean seasonal climatological, verified in the states of Maranhão, Piauí, and Tocantins (states of Mato Grosso). The La Niña (El Niño) events influenced positively (negatively) the annual rainfall anomalous pattern in Cerrado. Highlights The rainiest period occurs during September and April months (>200 mm·month−1). The driest period occurs during May and August months (<200 mm·month−1). 1985 (1990) year presents the most significant (smallest) annual rainfall average. The border zone between Amazon and Cerrado presents the highest annual rainfall.

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