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Skansi M.D.L.M.,Servicio Meteorologico Nacional | Brunet M.,Rovira i Virgili University | Brunet M.,University of East Anglia | Sigro J.,Rovira i Virgili University | And 13 more authors.
Global and Planetary Change | Year: 2013

Here we show and discuss the results of an assessment of changes in both area-averaged and station-based climate extreme indices over South America (SA) for the 1950-2010 and 1969-2009 periods using high-quality daily maximum and minimum temperature and precipitation series. A weeklong regional workshop in Guayaquil (Ecuador) provided the opportunity to extend the current picture of changes in climate extreme indices over SA.Our results provide evidence of warming and wetting across the whole SA since the mid-20th century onwards. Nighttime (minimum) temperature indices show the largest rates of warming (e.g. for tropical nights, cold and warm nights), while daytime (maximum) temperature indices also point to warming (e.g. for cold days, summer days, the annual lowest daytime temperature), but at lower rates than for minimums. Both tails of night-time temperatures have warmed by a similar magnitude, with cold days (the annual lowest nighttime and daytime temperatures) seeing reductions (increases). Trends are strong and moderate (moderate to weak) for regional-averaged (local) indices, most of them pointing to a less cold SA during the day and warmer night-time temperatures.Regionally-averaged precipitation indices show clear wetting and a signature of intensified heavy rain events over the eastern part of the continent. The annual amounts of rainfall are rising strongly over south-east SA (26.41. mm/decade) and Amazonia (16.09. mm/decade), but north-east Brazil and the western part of SA have experienced non-significant decreases. Very wet and extremely days, the annual maximum 5-day and 1-day precipitation show the largest upward trends, indicating an intensified rainfall signal for SA, particularly over Amazonia and south-east SA. Local trends for precipitation extreme indices are in general less coherent spatially, but with more general spatially coherent upward trends in extremely wet days over all SA. © 2012 Elsevier B.V.

Silva Junior J.A.,Federal University of Pará | Da Costa A.C.L.,Federal University of Pará | De Azevedo P.V.,Federal University of Campina Grande | Da Costa R.F.,University of Amazon | And 6 more authors.
Revista Brasileira de Meteorologia | Year: 2013

The ESECAFLOR/LBA experiment was carried out at the Caxiuanã National Forest, Pará State, and this article intends to investigate the effect of hydrological stress on the total soil respiration. Two adjacent 1 hectare plots were defined in January 2002. One plot remained in its natural conditions and was used as a control (A), while in the exclusion plot (B) plastic cover panels were installed in order to drain about 70% of the total rainfall to outside of the plot. Accumulated monthly rainfall was recorded from 2005 January to December. During 2005 the rainfall over the ECFPn was 2,211.6 mm, or 9.96% above the mean of 2,011.2 mm. The average soil moisture was 15.6±9.2 and 9.5±3.4% in the plots A and B, respectively. The average soil temperature was 25.6±0.4 and 25.7±0.5 oC, for the A and B plots, respectively. The average soil CO2 flux was 3.46±0.44 and 3.21±0.84 μmolCO2 m-2s-1 in the A and B plots, respectively. With the exclusion of part of rain in plot B, it had a reduction of 7.23% in the soil CO2 flux (0.25 μmolCO2 m-2s-1), 39.1% in the soil humidity (6.1p.p.), and an increase of 0.39% in the soil temperature (0.1oC). The soil moisture in parcel B was lesser than in the parcel A, due to the exclusion system of rain. However at the beginning of the year, site B undergone some changes causing the measuring values to be about the same on both areas.

Ramos A.M.,University of Évora | Ramos A.M.,Instituto Nacional Of Meteorologia Inmet | Conde F.C.,University of Évora | Conde F.C.,Instituto Nacional Of Meteorologia Inmet | And 7 more authors.
WIT Transactions on Ecology and the Environment | Year: 2010

The objective of this study is to investigate the atmospheric transport of gases and particles emitted by forest fires occurring on the Iberian Peninsula, affecting Continental Portugal during the period from 7 to 12 August 2003. The simulations were implemented using the on-line 3-D transport model CATTBRAMS (Coupled Aerosol and Tracer Transport to the Brazilian developments on the Regional Atmospheric Modeling System) coupled to an emission model. The results generated by CATT-BRAMS allow one to describe the local and synoptical condition at the target area. The wind direction from the northeast varying to east over the Iberian Peninsula favored the dislodgment of the smoke plume toward the Atlantic Ocean, distant from the regions with forest fire emissions. © 2010 WIT Press.

Lorz C.,Sudan University of Science and Technology | Abbt-Braun G.,Karlsruhe Institute of Technology | Bakker F.,Companhia de Saneamento Ambiental do Distrito Federal CAESB | Borges P.,Helmholtz Center for Environmental Research | And 15 more authors.
Environmental Earth Sciences | Year: 2012

Land-use/cover change (LUCC) and climate change are major controlling factors for water resources in the Distrito Federal in Western Central Brazil. Dynamic LUCC in the region has severe impacts on water resources, while climate changes during the last three decades is thought to have only moderate effects. LUCC affects water quantity mostly during base flow conditions. River basins with substantial expansion of agriculture since the end 1970s show a dramatic decrease of base flow discharge by 40-70%, presumably due to irrigation. In contrast, the effects of urbanization on runoff are less distinct, since factors controlling runoff generation might be more variable. For water quality, we found urban areas to have a strong influence on the parameters CSB, NH 4 +, and suspended solids. In addition, we assume emerging pollutants, e. g. organic (micro)pollutants, might play a major role in the future. The project IWAS-ÁGUA DF focuses on creating the scientific base to face these problems in frame of an IWRM concept for the region. Results of our study will be a contribution to an IRWM concept for the Distrito Federal and will help to maintain high standards in water supply for the region. © 2011 Springer-Verlag.

Ramos A.M.,Instituto Nacional Of Meteorologia Inmet | Conde F.C.,University of Évora | Moreira D.S.,National Institute for Space Research | Freitas S.R.,National Institute for Space Research | And 2 more authors.
Atmosfera | Year: 2012

Strong rainfall events have unquestionably one of the largest economic and social impacts of any atmospheric phenomena. The purpose of this paper is to simulate the weather conditions associated with the heavy precipitation episode during 11-13 March 2002, which generated intense rainfall as well as hail and snow in the central and northern regions of Continental Portugal. The simulation was carried out using the Regional Atmospheric Modeling System (RAMS), through a three nested grids configuration 48 km, 12 km and the highest resolution being 3 km, to capture the synoptic and mesoscale circulation patterns. The initial and lateral boundary conditions necessary to drive RAMS were taken from the Brazilian Center of Weather Prediction and Climate Studies (CPTEC) global model forecasts in the form of spectral coefficients with T62 triangular truncation equivalent to 1.825° resolution in the meridional and zonal directions. The model results show that the RAMS model is a useful framework to describe the rainfall patterns over the region, reproducing the area without rainfall within the domain reasonably well, although the model overestimated or underestimated the observed values at different periods. The spatial distribution of the total accumulated rainfall showed some tendency to predict more precipitation over higher elevations, probably influenced by dynamical forcing and associated microphysical processes.

Satyamurty P.,National Institute of Amazonian Research | Satyamurty P.,National Institute for Space Research | De Castro A.A.,National Institute of Amazonian Research | Tota J.,National Institute of Amazonian Research | And 2 more authors.
Theoretical and Applied Climatology | Year: 2010

Rainfall series at 18 stations along the major rivers of the Brazilian Amazon Basin, having data since 1920s or 1930s, are analyzed to verify if there are appreciable long-term trends. Annual, rainy-season, and dry-season rainfalls are individually analyzed for each station and for the region as a whole. Some stations showed positive trends and some negative trends. The trends in the annual rainfall are significant at only six stations, five of which reporting increasing trends (Barcelos, Belem, Manaus, Rio Branco, and Soure stations) and just one (Itaituba station) reporting decreasing trend. The climatological values of rainfall before and after 1970 show significant differences at six stations (Barcelos, Belem, Benjamin Constant, Iaurete, Itaituba, and Soure). The region as a whole shows an insignificant and weak downward trend; therefore, we cannot affirm that the rainfall in the Brazilian Amazon basin is experiencing a significant change, except at a few individual stations. Subregions with upward and downward trends are interspersed in space from the far eastern Amazon to western Amazon. Most of the seasonal trends follow the annual trends, thus, indicating a certain consistency in the datasets and analysis. © 2009 Springer-Verlag.

Buriol G.A.,Centro Universitario Franciscano | Estefanel V.,UNIFRA | Heldwein A.B.,Federal University of Santa Maria | Prestes S.D.,Instituto Nacional Of Meteorologia Inmet | Horn J.F.C.,Centro Universitario Franciscano
Ciencia Rural | Year: 2012

Coefficients a and b of the Angströn - Prescott equation to estimate global solar radiation for Santa Maria, RS were determined. Daily data of global solar radiation and sunshine, were obtained from the Meteorological Station which belongs to the 8th District of Meteorology, located on the campus of the Federal University of Santa Maria - UFSM, period from 2002 to 2008. The mentioned data were copied from the database of the 8th District of Meteorology - 8th DISME in Porto Alegre. Top of atmosphere radiation and possible maximum sunshine were calculated considering local latitude. With such elements, monthly regression equations were determined for the estimation of solar radiation as a function of insolation. We found a high correlation between insolation and global solar radiation and it's possible to estimate the solar radiation depending on the measured insolation.

Ferreira D.B.,National Institute for Space Research | Ferreira D.B.,Instituto Nacional Of Meteorologia Inmet | Ferreira D.B.,Instituto Nacional Of Meteorologia | Rao V.B.,National Institute for Space Research
Theoretical and Applied Climatology | Year: 2011

Recent climate variability in rainfall, temperatures (maximum and minimum), and the diurnal temperature range is studied with emphasis on its influence over soybean yields in southern Brazil, during 1969 to 2002. The results showed that the soybean (Glycine max L. Merril) yields are more affected by changes in temperature during summer, while changes in rainfall are more important during the beginning of plantation and at its peak of development. Furthermore, soybean yields in Paraná are more sensitive to rainfall variations, while soybean yields in the Rio Grande do Sul are more sensitive to variations in temperature. Effects of interannual climatic variability on soybean yields are evaluated through three agro-meteorological models: additive Stewart, multiplicative Rao, and multiplicative Jensen. The Jensen model is able to reproduce the interannual behavior of soybean yield reasonably well. © 2010 Springer-Verlag.

Ricarte R.M.D.,National Institute for Space Research | Herdies D.L.,National Institute for Space Research | Barbosa T.F.,Instituto Nacional Of Meteorologia Inmet
Meteorological Applications | Year: 2015

This study is based on climatological records (1979-2008) of cold outbreak (friagem) events that occurred in the southern Amazon region during the austral winter months (May to September). The friagem events were identified with an objective method that used climatological data from the surface station of the Department of Airspace Control (DCEA) in Vilhena city, including the minimum temperature (Tmin), the pressure reduced to mean sea level (Pmsl) and the decrease in Tmin (DTmin). The purpose of this study was to investigate the association between atmospheric circulation and friagem events using Climate Forecast System Reanalysis (CFSR) and a composite method. One hundred and forty-four friagem events were identified with the proposed methodology. These events produced large changes in weather conditions in Amazonia, including an abrupt decrease in air temperature, an increase in the amount of dry air, and an increase in surface pressure. The main atmospheric features associated with friagem events are an intensification of high post-frontal surface pressure that is caused by the intensification of a ridge at middle and high levels when air approaches the Andes and strong southerly winds at the surface that carry cold, dry air to tropical latitudes. © 2015 Royal Meteorological Society.

Borges P.A.,TU Dresden | Franke J.,TU Dresden | do Santos Silva F.D.,Instituto Nacional Of Meteorologia Inmet | Weiss H.,Helmholtz Center for Environmental Research | Bernhofer C.,TU Dresden
Theoretical and Applied Climatology | Year: 2014

In the framework of the IWAS/Água-DF project, this study focuses on changes in mean surface air temperature and accumulated precipitation in Central Brazil over the past 40 years. It has two main objectives: (1) comparison between two climatological periods (2001-2010 and 1971-2000) and (2) trend analysis of climate variables. Time series of meteorological and rain gauge stations from Central Brazil have been organized in a databank, which contains tools for homogeneity tests. From that, 4 temperature and 55 precipitation time series were sufficient homogeneous, while 1 temperature and 5 precipitation time series were identified as inhomogeneous. Reliable spatial distribution was produced using proper interpolation method. Trends and significance levels were calculated by Rapp's estimator of slope and Mann-Kendall test, respectively. The most important results of the comparisons and trend analysis in the last four decades are: (1) marked increase in annual and seasonal mean surface air temperature, (2) evident decreases of accumulated rainfall in winter and autumn, and (3) apparent increase of precipitation amounts in the rainy season. © 2013 Springer-Verlag Wien.

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