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Spatial and temporal variability of rainfall in eastern Amazon during the rainy season.

Ferreira DB, de Souza EB, de Moraes BC, Meira Filho LG - ScientificWorldJournal (2015)

Bottom Line: Empirical orthogonal functions (EOF) and composites analysis were employed on pentad data in order to investigate the tropical atmospheric-ocean patterns over the Atlantic Ocean and the spatial-temporal characteristics of the rainfall in eastern Amazon during the peak of the rainy season (February to April).The EOF results evidenced that the Intertropical Convergence Zone (ITCZ) is the main rainfall-producing system in eastern Amazon during the rainy season.Conditions associated with the southward SST gradient in the intertropical Atlantic formed the dynamic patterns that favored the position of the ITCZ to south of the equator, thus explaining the predominance of positive precipitation anomalies in eastern Amazon, especially in the state of Maranhão and northeastern Pará during the February and April months.

View Article: PubMed Central - PubMed

Affiliation: Vale Institute of Technology, Boaventura da Silva Street 955, 66055-090 Belém, PA, Brazil ; Post-Graduate Program in Environmental Sciences, Federal University of Pará, Augusto Corrêa Street 1, 66075-110 Belém, PA, Brazil.

ABSTRACT
Empirical orthogonal functions (EOF) and composites analysis were employed on pentad data in order to investigate the tropical atmospheric-ocean patterns over the Atlantic Ocean and the spatial-temporal characteristics of the rainfall in eastern Amazon during the peak of the rainy season (February to April). The EOF results evidenced that the Intertropical Convergence Zone (ITCZ) is the main rainfall-producing system in eastern Amazon during the rainy season. Conditions associated with the southward SST gradient in the intertropical Atlantic formed the dynamic patterns that favored the position of the ITCZ to south of the equator, thus explaining the predominance of positive precipitation anomalies in eastern Amazon, especially in the state of Maranhão and northeastern Pará during the February and April months.

No MeSH data available.


Related in: MedlinePlus

Composites for February (a) OLR anomalies in (W/m2) and wind at 200 hPa (stream lines), (b) SST anomalies (shaded in °C) and wind at 925 hPa (vectors m/s), (c) tropospheric circulation of Hadley in 050°W and Omega anomalies in colors, and (d) rainfall anomalies (mm/pentad), corresponding to the objectively selected events in the EOF1.
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fig4: Composites for February (a) OLR anomalies in (W/m2) and wind at 200 hPa (stream lines), (b) SST anomalies (shaded in °C) and wind at 925 hPa (vectors m/s), (c) tropospheric circulation of Hadley in 050°W and Omega anomalies in colors, and (d) rainfall anomalies (mm/pentad), corresponding to the objectively selected events in the EOF1.

Mentions: In Figure 4(a), the composites of the OLR anomalies indicate two large areas zonally oriented, with values lower than −10 W/m2. The first can be seen around the 05°N latitude and the second positioned over Northeast Brazil (NEB). This pattern suggests the formation of a double ITCZ band, which is normally associated with the rainy years. The double ITCZ usually happens to south of the main convective band in the first months of the year (FMA) with few-day duration [18]. The streamlines at 200 hPa wind characterize well the end of summer in the Southern Hemisphere, when the Bolivian High (BH) is well defined at approximately 15°S and 063°W, inducing tropical convection in eastern Amazon [19].


Spatial and temporal variability of rainfall in eastern Amazon during the rainy season.

Ferreira DB, de Souza EB, de Moraes BC, Meira Filho LG - ScientificWorldJournal (2015)

Composites for February (a) OLR anomalies in (W/m2) and wind at 200 hPa (stream lines), (b) SST anomalies (shaded in °C) and wind at 925 hPa (vectors m/s), (c) tropospheric circulation of Hadley in 050°W and Omega anomalies in colors, and (d) rainfall anomalies (mm/pentad), corresponding to the objectively selected events in the EOF1.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4352512&req=5

fig4: Composites for February (a) OLR anomalies in (W/m2) and wind at 200 hPa (stream lines), (b) SST anomalies (shaded in °C) and wind at 925 hPa (vectors m/s), (c) tropospheric circulation of Hadley in 050°W and Omega anomalies in colors, and (d) rainfall anomalies (mm/pentad), corresponding to the objectively selected events in the EOF1.
Mentions: In Figure 4(a), the composites of the OLR anomalies indicate two large areas zonally oriented, with values lower than −10 W/m2. The first can be seen around the 05°N latitude and the second positioned over Northeast Brazil (NEB). This pattern suggests the formation of a double ITCZ band, which is normally associated with the rainy years. The double ITCZ usually happens to south of the main convective band in the first months of the year (FMA) with few-day duration [18]. The streamlines at 200 hPa wind characterize well the end of summer in the Southern Hemisphere, when the Bolivian High (BH) is well defined at approximately 15°S and 063°W, inducing tropical convection in eastern Amazon [19].

Bottom Line: Empirical orthogonal functions (EOF) and composites analysis were employed on pentad data in order to investigate the tropical atmospheric-ocean patterns over the Atlantic Ocean and the spatial-temporal characteristics of the rainfall in eastern Amazon during the peak of the rainy season (February to April).The EOF results evidenced that the Intertropical Convergence Zone (ITCZ) is the main rainfall-producing system in eastern Amazon during the rainy season.Conditions associated with the southward SST gradient in the intertropical Atlantic formed the dynamic patterns that favored the position of the ITCZ to south of the equator, thus explaining the predominance of positive precipitation anomalies in eastern Amazon, especially in the state of Maranhão and northeastern Pará during the February and April months.

View Article: PubMed Central - PubMed

Affiliation: Vale Institute of Technology, Boaventura da Silva Street 955, 66055-090 Belém, PA, Brazil ; Post-Graduate Program in Environmental Sciences, Federal University of Pará, Augusto Corrêa Street 1, 66075-110 Belém, PA, Brazil.

ABSTRACT
Empirical orthogonal functions (EOF) and composites analysis were employed on pentad data in order to investigate the tropical atmospheric-ocean patterns over the Atlantic Ocean and the spatial-temporal characteristics of the rainfall in eastern Amazon during the peak of the rainy season (February to April). The EOF results evidenced that the Intertropical Convergence Zone (ITCZ) is the main rainfall-producing system in eastern Amazon during the rainy season. Conditions associated with the southward SST gradient in the intertropical Atlantic formed the dynamic patterns that favored the position of the ITCZ to south of the equator, thus explaining the predominance of positive precipitation anomalies in eastern Amazon, especially in the state of Maranhão and northeastern Pará during the February and April months.

No MeSH data available.


Related in: MedlinePlus