Browsing by Autor "Norberto Dani"

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Accumulation rate in a tropical Andean glacier as a proxy for northern Amazon precipitation
(Springer Science+Business Media, 2017) Rafael da Rocha Ribeiro; Jefferson Cárdia Simões; Edson Ramírez; Jean‐Denis Taupin; Elias Simão Assayag; Norberto Dani
Comment on tc-2021-186
(2021) Rafael S. dos Reis; Rafael da Rocha Ribeiro; Barbara Delmonte; Edson Ramírez; Norberto Dani; Paul A. Mayewski; Jefferson C. SimÃμes
Dust particle studies in ice cores from the tropical Andes provide important information about climate dynamics. We investigated dust concentrations from a 22.7 m ice-core recovered from the Quelccaya Ice Cap (QIC) in 2018, representing 12 years of snow accumulation. The dust seasonality signal was still preserved with some homogenization of the record due to surface melting and percolation. Using a microparticle counter, we measured the dust concentration from 2–60 µm and divided the annual dust concentration into three distinct groups: fine particle percentage (FPP, 2–10 µm), coarse particle percentage (CPP, 10–20 μm) and giant particle percentage (GPP, 20–60 μm). Increased dust was associated with the warm stage of the Pacific Decadal Oscillation index (PDO) from 2014–2017 with significant increases in FPP and a relative decrease in GPP. There was a positive correlation between PDO and FPP (r = 0.68, p-value < 0.02). CPP and GPP were dominant during the PDO cold phase (2005–2013) and were more strongly associated with the Tropical Northern Atlantic index (TNA), which was positive from 2005–2017. The relation between TNA and CPP was r = 0.60 (p-value < 0.05) and that with GPP was r = 0.59 (p-value < 0.05). We also revealed a potential link between QIC dust and Madeira River sediments and runoff. Sediment concentration decreases at Porto Velho station were correlated with %GPP (r = 0.67, p < 0.02) from 2005–2017. This relationship contributes to a better understanding of the effects of PDO oscillations on both parameters. The %GPP and sediment decreases were potentially linked with the PDO phase change from negative to positive. We also noted a strong negative correlation between FPP and runoff (r = −0.80, p < 0.002) from 2005–2016, which was understandable due to the relationship of FPP to wetter conditions while runoff decreases were associated with increasing dryness in the southern part of the Madeira Basin. Assessing dust record variability by distinct size groups can help to improve our knowledge of how the Pacific and Atlantic oceans influence atmospheric oscillations in the QIC. In addition, the association of dust variability with dynamic changes in sediments and runoff in the Madeira River system demonstrates the potential for future investigation of linkages between QIC dust and Amazon basin rivers.
Comment on tc-2021-186
(2021) Rafael S. dos Reis; Rafael da Rocha Ribeiro; Barbara Delmonte; Edson Ramírez; Norberto Dani; Paul A. Mayewski; Jefferson C. SimÃμes
Dust particle studies in ice cores from the tropical Andes provide important information about climate dynamics. We investigated dust concentrations from a 22.7 m ice-core recovered from the Quelccaya Ice Cap (QIC) in 2018, representing 12 years of snow accumulation. The dust seasonality signal was still preserved with some homogenization of the record due to surface melting and percolation. Using a microparticle counter, we measured the dust concentration from 2–60 µm and divided the annual dust concentration into three distinct groups: fine particle percentage (FPP, 2–10 µm), coarse particle percentage (CPP, 10–20 μm) and giant particle percentage (GPP, 20–60 μm). Increased dust was associated with the warm stage of the Pacific Decadal Oscillation index (PDO) from 2014–2017 with significant increases in FPP and a relative decrease in GPP. There was a positive correlation between PDO and FPP (r = 0.68, p-value < 0.02). CPP and GPP were dominant during the PDO cold phase (2005–2013) and were more strongly associated with the Tropical Northern Atlantic index (TNA), which was positive from 2005–2017. The relation between TNA and CPP was r = 0.60 (p-value < 0.05) and that with GPP was r = 0.59 (p-value < 0.05). We also revealed a potential link between QIC dust and Madeira River sediments and runoff. Sediment concentration decreases at Porto Velho station were correlated with %GPP (r = 0.67, p < 0.02) from 2005–2017. This relationship contributes to a better understanding of the effects of PDO oscillations on both parameters. The %GPP and sediment decreases were potentially linked with the PDO phase change from negative to positive. We also noted a strong negative correlation between FPP and runoff (r = −0.80, p < 0.002) from 2005–2016, which was understandable due to the relationship of FPP to wetter conditions while runoff decreases were associated with increasing dryness in the southern part of the Madeira Basin. Assessing dust record variability by distinct size groups can help to improve our knowledge of how the Pacific and Atlantic oceans influence atmospheric oscillations in the QIC. In addition, the association of dust variability with dynamic changes in sediments and runoff in the Madeira River system demonstrates the potential for future investigation of linkages between QIC dust and Amazon basin rivers.
Mudanças Investigadas nas Massas de Gelo dos Andes Tropicais
(Brazilian Association of Water Resources, 2010) Rafael Vasconcelos Ribeiro; Jefferson Cárdia Simões; Norberto Dani; Jorge Lopes Cavalcante Neto; Edson Ramírez
Relationships between Andean Glacier Ice-Core Dust Records and Amazon Basin Riverine Sediments
(2021) Rafael S. dos Reis; Rafael da Rocha Ribeiro; Barbara Delmonte; Edson Ramírez; Norberto Dani; Paul A. Mayewski; Jefferson Cárdia Simões
Abstract. Dust particle studies in ice cores from the tropical Andes provide important information about climate dynamics. We investigated dust concentrations from a 22.7 m ice-core recovered from the Quelccaya Ice Cap (QIC) in 2018, representing 12 years of snow accumulation. The dust seasonality signal was still preserved with some homogenization of the record due to surface melting and percolation. Using a microparticle counter, we measured the dust concentration from 2–60 µm and divided the annual dust concentration into three distinct groups: fine particle percentage (FPP, 2–10 µm), coarse particle percentage (CPP, 10–20 μm) and giant particle percentage (GPP, 20–60 μm). Increased dust was associated with the warm stage of the Pacific Decadal Oscillation index (PDO) from 2014–2017 with significant increases in FPP and a relative decrease in GPP. There was a positive correlation between PDO and FPP (r = 0.68, p-value < 0.02). CPP and GPP were dominant during the PDO cold phase (2005–2013) and were more strongly associated with the Tropical Northern Atlantic index (TNA), which was positive from 2005–2017. The relation between TNA and CPP was r = 0.60 (p-value < 0.05) and that with GPP was r = 0.59 (p-value < 0.05). We also revealed a potential link between QIC dust and Madeira River sediments and runoff. Sediment concentration decreases at Porto Velho station were correlated with %GPP (r = 0.67, p < 0.02) from 2005–2017. This relationship contributes to a better understanding of the effects of PDO oscillations on both parameters. The %GPP and sediment decreases were potentially linked with the PDO phase change from negative to positive. We also noted a strong negative correlation between FPP and runoff (r = −0.80, p < 0.002) from 2005–2016, which was understandable due to the relationship of FPP to wetter conditions while runoff decreases were associated with increasing dryness in the southern part of the Madeira Basin. Assessing dust record variability by distinct size groups can help to improve our knowledge of how the Pacific and Atlantic oceans influence atmospheric oscillations in the QIC. In addition, the association of dust variability with dynamic changes in sediments and runoff in the Madeira River system demonstrates the potential for future investigation of linkages between QIC dust and Amazon basin rivers.
The Recent Relationships Between Andean Ice-Core Dust Record and Madeira River Suspended Sediments on the Wet Season
(Frontiers Media, 2022) Rafael S. dos Reis; Rafael da Rocha Ribeiro; Barbara Delmonte; Edson Ramírez; Norberto Dani; Paul A. Mayewski; Jefferson Cárdia Simões
Dust particle studies in ice cores from the tropical Andes provide important information about climate dynamics. We investigated dust concentrations from a 22.7 m ice-core recovered from the Quelccaya Ice Cap (QIC) in 2018, representing 14 years of snow accumulation. The dust seasonality signal was still preserved with homogenization of the record due to surface melting and percolation. Using a microparticle counter, we measured the dust concentration from 2 to 60 µm and divided the annual dust concentration into three distinct groups: fine particle percentage (FPP, 2–10 µm), coarse particle percentage (CPP, 10–20 μm), and giant particle percentage (GPP, 20–60 μm). Increased dust was associated with the warm stage of the Pacific Decadal Oscillation index (PDO) after 2013 with significant increases in FPP and a relative decrease in CPP and GPP. There was a positive correlation between PDO and FPP (r = 0.70, p -value &lt; 0.005). CPP and GPP were dominant during the mainly PDO cold phase (2003–2012). The FPP increase record occurs during the positive phase of PDO and snow accumulation decrease. We also revealed a potential link between QIC record and Madeira River during the wet season through two relationships: between QIC snow accumulation and runoff during transitional season, QIC dust, and suspended sediments during high-water discharge. The snow accumulation (during September-November) and runoff (during November-January) relationship present similar variability using a time-lag (60 days) while total dust and FPP group are associated with average suspended sediments concentration during February-April. Assessing dust record variability by distinct size groups can help to improve our knowledge of how the Pacific ocean influence dust record in the QIC. In addition, the association of snow accumulation and dust variability with dynamic changes in suspended sediments load and runoff in the Madeira River system demonstrates the potential for future investigation of linkages between QIC record and Amazon basin rivers.