scholarly journals Extreme Drought in the Brazilian Pantanal in 2019–2020: Characterization, Causes, and Impacts

2021 ◽  
Vol 3 ◽  
Author(s):  
Jose A. Marengo ◽  
Ana P. Cunha ◽  
Luz Adriana Cuartas ◽  
Karinne R. Deusdará Leal ◽  
Elisangela Broedel ◽  
...  
Keyword(s):  
South America ◽  
Monsoon Season ◽  
Summer Rainfall ◽  
Economic Consequences ◽  
Extreme Drought ◽  
Air Masses ◽  
Paraguay River ◽  
Prolonged Drought ◽  
Drought Conditions ◽  
Brazilian Pantanal

The Pantanal region in South America is one of the world's largest wetlands. Since 2019, the Pantanal has suffered a prolonged drought that has spelled disaster for the region, and subsequent fires have engulfed hundreds of thousands of hectares. The lack of rainfall during the summers of 2019 and 2020 was caused by reduced transport of warm and humid summer air from Amazonia into the Pantanal. Instead, a predominance of warmer and drier air masses from subtropical latitudes contributed to a scarcity of summer rainfall at the peak of the monsoon season. This led to prolonged extreme drought conditions across the region. This drought had severe impacts on the hydrology of the Pantanal. Hydrometric levels fell all along the Paraguay River. In 2020, river levels reached extremely low values, and in some sections of this river, transportation had to be restricted. Very low river levels affected the mobility of people and shipping of soybeans and minerals to the Atlantic Ocean by the Hidrovia -Paraná-Paraguai (Paraná-Paraguay Waterway). This study is directed to better understand the hydroclimatic aspects of the current drought in the Brazilian Pantanal and their impacts on natural and human systems. As a consequence of the drought, fires spread and affected natural biodiversity as well as the agribusiness and cattle ranching sectors. While fires had serious socioecological and economic consequences, we do not intend to investigate the effect of the downstream low-level waters on the Pantanal ecosystems or the drought in the risk of fire.

scholarly journals Hydroclimatic Controls on the Isotopic (δ18 O, δ2 H, d-excess) Traits of Pan-Arctic Summer Rainfall Events

2021 ◽  
Vol 9 ◽  
Author(s):  
Moein Mellat ◽  
Hannah Bailey ◽  
Kaisa-Riikka Mustonen ◽  
Hannu Marttila ◽  
Eric S. Klein ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Cycle ◽  
Global Climate ◽  
Meteorological Data ◽  
Summer Rainfall ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Arctic Water ◽  
Ongoing Research ◽  
Air Masses

Arctic sea-ice loss is emblematic of an amplified Arctic water cycle and has critical feedback implications for global climate. Stable isotopes (δ18O, δ2H, d-excess) are valuable tracers for constraining water cycle and climate processes through space and time. Yet, the paucity of well-resolved Arctic isotope data preclude an empirically derived understanding of the hydrologic changes occurring today, in the deep (geologic) past, and in the future. To address this knowledge gap, the Pan-Arctic Precipitation Isotope Network (PAPIN) was established in 2018 to coordinate precipitation sampling at 19 stations across key tundra, subarctic, maritime, and continental climate zones. Here, we present a first assessment of rainfall samples collected in summer 2018 (n = 281) and combine new isotope and meteorological data with sea ice observations, reanalysis data, and model simulations. Data collectively establish a summer Arctic Meteoric Water Line where δ2H = 7.6⋅δ18O–1.8 (r2 = 0.96, p < 0.01). Mean amount-weighted δ18O, δ2H, and d-excess values were −12.3, −93.5, and 4.9‰, respectively, with the lowest summer mean δ18O value observed in northwest Greenland (−19.9‰) and the highest in Iceland (−7.3‰). Southern Alaska recorded the lowest mean d-excess (−8.2%) and northern Russia the highest (9.9‰). We identify a range of δ18O-temperature coefficients from 0.31‰/°C (Alaska) to 0.93‰/°C (Russia). The steepest regression slopes (>0.75‰/°C) were observed at continental sites, while statistically significant temperature relations were generally absent at coastal stations. Model outputs indicate that 68% of the summer precipitating air masses were transported into the Arctic from mid-latitudes and were characterized by relatively high δ18O values. Yet 32% of precipitation events, characterized by lower δ18O and high d-excess values, derived from northerly air masses transported from the Arctic Ocean and/or its marginal seas, highlighting key emergent oceanic moisture sources as sea ice cover declines. Resolving these processes across broader spatial-temporal scales is an ongoing research priority, and will be key to quantifying the past, present, and future feedbacks of an amplified Arctic water cycle on the global climate system.

scholarly journals Impact of different Asian source regions on the composition of the Asian monsoon anticyclone and of the extratropical lowermost stratosphere

2015 ◽  
Vol 15 (23) ◽  
pp. 13699-13716 ◽  
Author(s):  
B. Vogel ◽  
G. Günther ◽  
R. Müller ◽  
J.-U. Grooß ◽  
M. Riese
Keyword(s):  
Chemical Composition ◽  
Southeast Asia ◽  
Asian Monsoon ◽  
Monsoon Season ◽  
Intraseasonal Variability ◽  
Air Masses ◽  
Northern India ◽  
Source Regions ◽  
The Tropics ◽  
Emission Tracers

Abstract. The impact of different boundary layer source regions in Asia on the chemical composition of the Asian monsoon anticyclone, considering its intraseasonal variability in 2012, is analysed by simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS) using artificial emission tracers. The horizontal distribution of simulated CO, O3, and artificial emission tracers for India/China are in good agreement with patterns found in satellite measurements of O3 and CO by the Aura Microwave Limb Sounder (MLS). Using in addition, correlations of artificial emission tracers with potential vorticity demonstrates that the emission tracer for India/China is a very good proxy for spatial distribution of trace gases within the Asian monsoon anticyclone. The Asian monsoon anticyclone constitutes a horizontal transport barrier for emission tracers and is highly variable in location and shape. From the end of June to early August, a northward movement of the anticyclone and, during September, a strong broadening of the spatial distribution of the emission tracer for India/China towards the tropics are found. In addition to the change of the location of the anticyclone, the contribution of different boundary source regions to the composition of the Asian monsoon anticyclone in the upper troposphere strongly depends on its intraseasonal variability and is therefore more complex than hitherto believed. The largest contributions to the composition of the air mass in the anticyclone are found from northern India and Southeast Asia at a potential temperature of 380 K. In the early (mid-June to mid-July) and late (September) period of the 2012 monsoon season, contributions of emissions from Southeast Asia are highest; in the intervening period (early August), emissions from northern India have the largest impact. Our findings show that the temporal variation of the contribution of different convective regions is imprinted in the chemical composition of the Asian monsoon anticyclone. Air masses originating in Southeast Asia are found both within and outside of the Asian monsoon anticyclone because these air masses experience, in addition to transport within the anticyclone, upward transport at the southeastern flank of the anticyclone and in the tropics. Subsequently, isentropic poleward transport of these air masses occurs at around 380 K with the result that the extratropical lowermost stratosphere in the Northern Hemisphere is flooded by the end of September with air masses originating in Southeast Asia. Even after the breakup of the anticyclonic circulation (around the end of September), significant contributions of air masses originating in India/China are still found in the upper troposphere over Asia. Our results demonstrate that emissions from India, China, and Southeast Asia have a significant impact on the chemical composition of the lowermost stratosphere of the Northern Hemisphere, in particular at the end of the monsoon season in September/October 2012.

scholarly journals Impact of the 2012 extreme drought conditions on private well owners in the United States, a qualitative analysis

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Michelle Murti ◽  
Ellen Yard ◽  
Rachel Kramer ◽  
Dirk Haselow ◽  
Mike Mettler ◽  
...  
Keyword(s):  
United States ◽  
Qualitative Analysis ◽  
The United States ◽  
Extreme Drought ◽  
Drought Conditions

scholarly journals Quantitative Determination Procedures for Regional Extreme Drought Conditions: Application to Historical Drought Events in South Korea

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 581
Author(s):  
Chan Wook Lee ◽  
Moo Jong Park ◽  
Do Guen Yoo
Keyword(s):  
South Korea ◽  
Quantitative Determination ◽  
Water Availability ◽  
Comprehensive Evaluation ◽  
Extreme Drought ◽  
Historical Event ◽  
The Past ◽  
Five Factors ◽  
Drought Conditions ◽  
The Status

Recently, the signs of extreme droughts, which were thought of as exceptional and unlikely, are being detected worldwide. It is necessary to prepare countermeasures against extreme droughts; however, current definitions of extreme drought are just used as only one or two indicators to represent the status or severity of a drought. More representative drought factors, which can show the status and severity that are relevant to extreme drought, need to be considered depending on the characteristics of the drought and comprehensive evaluation of various indices. Therefore, this study attempted to quantitatively define regional extreme droughts using more acceptable factors. The methodology comprises five factors that are indicative of extreme drought. The five factors are (1) duration (days), (2) number of consecutive years (years), (3) water availability, (4) return period, and (5) regional experience. The results were analyzed by applying the procedure to droughts that took place in 2014–2015 in South Korea. The results showed that the applied historical event did not enter the status of extreme drought, which is proposed in this study; however, the proposed methodology is applicable because it uses acceptable and reasonable factors to judge extreme drought, but it can also take into account the past regional experience of extreme drought.

scholarly journals The Early Triassic magmatism of the Alto Paraguay Province, Central South America: Paleomagnetic and ASM data

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Marcia Ernesto ◽  
Piero Comin-Chiaramonti ◽  
Celso de Barros Gomes
Keyword(s):  
South America ◽  
Lava Flows ◽  
Early Triassic ◽  
Paraguay River ◽  
Magnetic Components ◽  
Paleomagnetic Pole ◽  
Intrusive Rocks ◽  
Alkaline Complexes ◽  
Central South

AbstractA paleomagnetic studystudywork was carried out on the Alto Paraguay Province (APP), a belt of alkaline complexes that parallel the Paraguay river for more than 40 km at the border of Brazil and Paraguay. The province is well dated by 40Ar/39Ar method giving ages in the range 240–250 Ma with a preferred age of 241 Ma. Intrusive rocks are predominant but the stocks may be topped by lava flows and ignimbrites. Paleomagnetic work on stocks, dikes and flows of the APP identified normal and reversed magnetic components which are carried mainly by titanomagnetites. The calculated paleomagnetic pole located at 319ºE 78ºS (α

scholarly journals Transformation and aging of biomass burning carbonaceous aerosol over tropical South America from aircraft in-situ measurements during SAMBBA

2019 ◽  
Author(s):  
William T. Morgan ◽  
James D. Allan ◽  
Stéphane Bauguitte ◽  
Eoghan Darbyshire ◽  
Michael J. Flynn ◽  
...  
Keyword(s):  
South America ◽  
Biomass Burning ◽  
Chemical Properties ◽  
Carbonaceous Aerosol ◽  
Air Masses ◽  
Atmospheric Aging ◽  
Primary Driver ◽  
Tropical South America

Abstract. We present a range of airborne in-situ observations of biomass burning carbonaceous aerosol over tropical South America, including a case study of a large tropical forest wildfire and a series of regional survey flights across the Brazilian Amazon and Cerrado. The study forms part of the South American Biomass Burning Analysis (SAMBBA) Project, which was conducted during September and October 2012. We find limited evidence for net increases in aerosol mass through atmospheric aging combined with substantial changes in the chemical properties of organic aerosol (OA). Oxidation of the OA increases significantly and rapidly on the scale of 2.5–3 hours based on our case study analysis and is consistent with secondary organic aerosol production. The observations of limited net enhancement in OA coupled with such changes in chemical composition, imply that evaporation of OA is also occurring to balance these changes. We observe significant coatings on black carbon particles at source, but with limited changes with aging in both particle core size and coating thickness. We quantify variability in the ratio of OA to carbon monoxide across our study as a key parameter representing both initial fire conditions and an indicator of net aerosol production with atmospheric aging. We observe ratios of 0.075–0.13 μg sm−3 ppbv−1 in the west of our study region over the Amazon tropical forest in air masses less influenced by precipitation and a value of 0.095 μg sm−3 ppbv−1 over the Cerrado environment in the east. Such values are consistent with emission factors used by numerical models to represent biomass burning OA emissions. Black carbon particle core sizes typically range from 250–290 nm, while coating thicknesses range from 40–110 nm in air masses less influenced by precipitation. The primary driver of the variability we observe appears to be related to changes at the initial fire source. A key lesson from our study is that the complex nature of the regional aerosol and its drivers precludes aggregating our observations as a function of atmospheric aging due to the many conflating and competing factors present. Our study explores and quantifies key uncertainties in the evolution of biomass burning aerosol at both nearfield and regional scales. Our results suggest that the initial conditions of the fire are the primary driver of carbonaceous aerosol physical and chemical properties over tropical South America, aside from significant oxidation of OA during atmospheric aging. Such findings imply that uncertainties in the magnitude of the aerosol burden and its impact on weather, climate, health and natural ecosystems most likely lie in quantifying emission sources, alongside atmospheric dispersion, transport and removal rather than chemical enhancements in mass.

scholarly journals Diurnal Above-ground Movement in Hairy-tailed Moles, Parascalops breweri

2008 ◽  
Vol 122 (3) ◽  
pp. 267 ◽  
Author(s):  
Erin E. Fraser ◽  
Johnston F. Miller
Keyword(s):  
First Record ◽  
Ground Movement ◽  
Extreme Drought ◽  
Drought Conditions ◽  
Young Of The Year

We report the first record of Hairy-tailed Moles (Parascalops breweri) moving above ground during the day and suggest that the four individuals observed were young-of-the-year dispersing from their natal territories. Extreme drought conditions may also have driven these animals to move above ground.

Two new species of Pontederia L. (Pontederiaceae Kunth) to South America

Phytotaxa ◽  
2020 ◽  
Vol 432 (3) ◽  
pp. 252-262
Author(s):  
DANILO J.L. SOUSA ◽  
GABRIELA B. SIQUEIRA ◽  
ANA MARIA GIULIETTI
Keyword(s):  
New Species ◽  
South America ◽  
Leaf Blade ◽  
East Coast ◽  
Northeastern Brazil ◽  
Small Populations ◽  
Key To Species ◽  
Two New Species ◽  
Semiarid Areas ◽  
Brazilian Pantanal

Two new species of Pontederia are here described and illustrated. Pontederia gigantea is similar to P. sagittata by its sagittate leaf blade, but the first one presents blue flowers while the second one has whitish to pinkish flowers. Besides that, P. gigantea is endemic to Brazil, occurring in small populations through the east coast, in the Atlantic Rainforest. Meanwhile, P. sagittata occurs in the south of Mexico and Honduras. Pontederia reflexa occurs disjunctly in South America, in Northeastern Brazil, where its distribution is linked to semiarid areas; and in Bolivia, Paraguay and Brazilian Pantanal. This species is related to the whitish-flowered species of Pontederia, and is differentiated from other species of Pontederia by the reflex and revolute spathe. An updated identification key to species of Pontederia and a map showing the geographic distribution of the new taxa are also provided.

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