Variações de intensidade do campo geomagnético em Santa Maria (Brasil) para os últimos 3 mil anos

Earth magnetic field variations at secular scales and at hundred quilometers have internal origin at the outer core. The most important feature associated with this internal field is the South Atlantic Magnetic Anomaly (SAMA), which covers the South America and it is characterized by the lowest total field intensity at the surface. Here, we investigate the geomagnetic field variations in Santa Maria (Brazil) over the past 3 ka. Results indicate that the intensities observed in Santa Maria are the lowest of the geomagnetic field over the past 3 ka. The consequences of these field features could be the increase in the electrically charged particles reaching the low Earth atmosphere that may generate problems in the communications systems or climate changes.As variações do campo magnético terrestre em escala temporal secular e escala espacial da ordem de centenas de quilômetros geralmente tem origem no núcleo externo da Terra. A feição mais marcante associada ao campo geomagnético interno é a Anomalia Magnética do Atlântico Sul (AMAS), que atualmente cobre todo o sul da América do Sul, e é caracterizada pelas menores intensidades do campo geomagnético em toda a superfície da Terra. Neste trabalho investigamos as variações geomagnéticas temporais para os últimos 3 mil anos, registradas em Santa Maria, localizada na área influenciada pela AMAS. Os resultados indicam que as intensidades geomagnéticas observadas atualmente são as mais baixas dos últimos 3 mil anos. Como consequência destes fenômenos, o aumento na incidência de partículas eletricamente carregadas que chegam até a baixa atmosfera da Terra, pode gerar problemas desde sistemas de comunicação até mesmo no clima do planeta

Relationship Between Extreme Rainfall Occurrences and Galactic Cosmic Rays over Natal/RN, Brazil: A Case Study

Abstract The increase in Galactic Cosmic Rays (GCR) flux intensity induces the Condensation Nuclei (CN) production, which intensifies rainfall occurrences. Then, the objective of this study was to analyze the rainfall distribution in the NEB and the impact of GCR flux on extreme rainfall events occurred in July 1998 in Natal/RN, Brazil. We used historical rainfall, Sea Surface Temperature (SST) and GCR flux data for Natal/RN. We used R software for statistical analysis. The results indicate that the GCR flux is important for intensifying extremes rainfall occurrences. This fact is observed when analyzing the relationship between rainfall greater than 10 mm and GCR flux above 6,390 counts/min. Pearson correlation coefficient between rainfall and GCR flux was 0.94 (p-value = 0.0005) and SST was -0.76 (p-value = 0.0263), both statistically significant. The rate between GCR flux and rainfall was +2.87 mm/count/min, while the rate between SST and rainfall was -7.91 mm/°C. The variance proportion explained by regression was 94.41%, with relative importance degree corresponding to 62.0% for GCR flux and 32.4% for SST, respectively. The results show that GCR flux had a greater contribution to extreme rainfall occurrence in the metropolitan region of Natal/RN and it is important in climatological studies

Identificação do uso e ocupação do solo por caracterização morfométrica e por pesquisa de campo da bacia hidrográfica rio das cobras

El presente trabajo tuvo como objetivo diagnosticar el uso y la ocupación del suelo y el área de preservación permanente en la cuenca del río das Cobras, utilizando técnicas de geoprocesamiento. Esta cuenca tiene un área de 617,20 km² ubicada en los municipios de Nova Laranjeiras - PR, Espigão Alto Iguaçu - PR y Quedas do Iguaçu - PR, su río principal desemboca en el río Iguaçu. Además de los municipios, esta área está ocupada por comunidades indígenas, campesinos y por la agricultura intensiva, por lo que se tiene un gran interés en su estudo.The present work had as objective to diagnose the use and occupation of the soil and the permanent preservation area in the Cobras River basin, using Geoprocessing techniques. This basin with an area of 617.20 km ², located in the municipalities of Nova Laranjeiras - PR, Espigão Alto Iguaçu - PR and Quedas do Iguaçu - PR, your river has the mouth in Iguaçu River. This area is occupied, in addition to the municipalities, by indigenous community and by settlement of landless, thus having great interest of study, also occupied with the intensive agriculture.O presente trabalho teve como objetivo diagnosticar o uso e ocupação do solo e a área de preservação permanente na bacia do Rio das Cobras, utilizando técnicas de Geoprocessamento. Bacia essa com uma área de 617,20 km² localizada nos municípios de Nova Laranjeiras – PR, Espigão Alto Iguaçu – PR e Quedas do Iguaçu – PR, seu rio principal deságua no rio Iguaçu. Esta área é ocupada, além dos municípios, por comunidade indígena e por assentamento de sem terras, tendo assim grande interesse de estudo, também ocupada com a agricultura intensiva

Multidecadal climate variability in Brazil's Nordeste during the last 3000 years based on speleothem isotope records

We present the first high resolution, approximately similar to 4 years sample spacing, precipitation record from northeastern Brazil (hereafter referred to as 'Nordeste') covering the last similar to 3000 yrs from Th-230-dated stalagmites oxygen isotope records. Our record shows abrupt fluctuations in rainfall tied to variations in the intensity of the South American summer monsoon (SASM), including the periods corresponding to the Little Ice Age (LIA), the Medieval Climate Anomaly (MCA) and an event around 2800 yr B.P. Unlike other monsoon records in southern tropical South America, dry conditions prevailed during the LIA in the Nordeste. Our record suggests that the region is currently undergoing drought conditions that are unprecedented over the past 3 millennia, rivaled only by the LIA period. Using spectral, wavelet and cross-wavelet analyses we show that changes in SASM activity in the region are mainly associated with variations of the Atlantic Multidecadal Oscillation (AMO) and to a lesser degree caused by fluctuations in tropical Pacific SST. Our record also shows a distinct periodicity around 210 years, which has been linked to solar variability. Citation: Novello, V. F., et al. (2012), Multidecadal climate variability in Brazil's Nordeste during the last 3000 years based on speleothem isotope records, Geophys. Res. Lett., 39, L23706, doi: 10.1029/2012GL053936.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), BrazilFundacao de Amparo a Pesquisa do Estado de Sao Paulo, Brazil (FAPESP) [2006/06761-0, 2011/39450394]CNSFCNSF [41230524]U.S. NSF [0502535, 3961103404, 1003690]U.S. NSF[2013CB955902