Climate change impact on precipitation for the Amazon and La Plata basins   总被引：2，自引：0，他引：2  

Marta Llopart  Erika Coppola  Filippo Giorgi  Rosmeri P. da Rocha  Santiago V. Cuadra 《Climatic change》2014,125(1):111-125

We analyze the local and remote impacts of climate change on the hydroclimate of the Amazon and La Plata basins of South America (SA) in an ensemble of four 21st century projections (1970–2100, RCP8.5 scenario) with the regional climate model RegCM4 driven by the HadGEM, GFDL and MPI global climate models (GCMs) over the SA CORDEX domain. Two RegCM4 configurations are used, one employing the CLM land surface and the Emanuel convective schemes, and one using the BATS land surface and Grell (over land) convection schemes. First, we find considerable sensitivity of the precipitation change signal to both the driving GCM and the RegCM4 physics schemes (with the latter even greater than the first), highlighting the pronounced uncertainty of regional projections over the region. However, some improvements in the simulation of the annual cycle of precipitation over the Amazon and La Plata basins is found when using RegCM4, and some consistent change signals across the experiments are found. One is a tendency towards an extension of the dry season over central SA deriving from a late onset and an early retreat of the SA monsoon. The second is a dipolar response consisting of reduced precipitation over the broad Amazon and Central Brazil region and increased precipitation over the La Plata basin and central Argentina. An analysis of the relative influence on the change signal of local soil-moisture feedbacks and remote effects of Sea Surface Temperature (SST) over the Niño 3.4 region indicates that the former is prevalent over the Amazon basin while the latter dominates over the La Plata Basin. Also, the soil moisture feedback has a larger role in RegCM4 than in the GCMs.  相似文献   

Simulation of non-Gaussian cosmic microwave background maps     

Graca Rocha  M. P. Hobson  Sarah Smith  Pedro Ferreira  Anthony Challinor 《Monthly notices of the Royal Astronomical Society》2005,357(1):1-11

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Environmental issues in urban groundwater systems: a multidisciplinary study of the Paranhos and Salgueiros spring waters,Porto (NW Portugal)   总被引：1，自引：1，他引：0  

Maria José Afonso  Helder I. Chaminé  José M. Marques  Paula M. Carreira  Laura Guimarães  Lúcia Guilhermino  Alberto Gomes  Paulo E. Fonseca  Ana Pires  Fernando Rocha 《Environmental Earth Sciences》2010,61(2):379-392

This study presents the results of a multidisciplinary approach, using hydrogeochemical, isotopic and ecotoxicological analyses, performed to assess the nature and suitability for use of Paranhos and Salgueiros spring waters (Porto city, NW Portugal). Based on the surface activities located along the course of the springs, 23 water samples were collected. All the samples were analysed for major element concentrations. The isotopic techniques employed included δ²H, δ¹⁸O and ³H. Standard acute bioassays with Daphnia magna were also performed. The hydrogeochemical analyses showed a nitrate and sulphate-enriched composition for these groundwaters, resulting mainly from urban drainage and sewer leakage. In the ecotoxicological analyses, no significant mortality was observed in any of the tests performed. The results obtained in this study suggest that Porto urban groundwater could be suitable for irrigation uses.  相似文献   

Climatic simulations of the eastern Andes low-level jet and its dependency on convective parameterizations     

Maria Cristina Lemos da Silva  Rosmeri Porfírio da Rocha  Rita Yuri Ynoue 《Meteorology and Atmospheric Physics》2010,108(1-2):9-27

The South American low level jet (SALLJ) of the Eastern Andes is investigated with Regional Climate Model version 3 (RegCM3) simulations during the 2002–2003 austral summer using two convective parameterizations (Grell and Emanuel). The simulated SALLJ is compared with the special observations of SALLJEX (SALLJ Experiment). Both the Grell and Emanuel schemes adequately simulate the low level flow over South America. However, there are some intensity differences. Due to the larger (smaller) convective activity, the Emanuel (Grell) scheme simulates more intense (weaker) low level wind than analysis in the tropics and subtropics. The objectives criteria of Sugahara (SJ) and Bonner (BJ) were used for LLJ identification. When applied to the observations, both criteria suggest a larger frequency of the SALLJ in Santa Cruz, followed by Mariscal, Trinidad and Asunción. In Mariscal and Asunción, the diurnal cycle indicates that SJ occurs mainly at 12 UTCs (morning), while the BJ criterion presents the SALLJ as more homogenously distributed. The concentration into two of the four-times-a-day observations does not allow conclusions about the diurnal cycle in Santa Cruz and Trinidad. The simulated wind profiles result in a lower than observed frequency of SALLJ using both the SJ and BJ criteria, with fewer events obtained with the BJ. Due to the stronger simulated winds, the Emanuel scheme produces an equal or greater relative frequency of SALLJ than the Grell scheme. However, the Grell scheme using the SJ criterion simulates the SALLJ diurnal cycle closer to the observed one. Although some discrepancies between observed and simulated mean vertical profiles of the horizontal wind are noted, there is large agreement between the composites of the vertical structure of the SALLJ, especially when the SJ criterion is used with the Grell scheme. On an intraseasonal scale, a larger southward displacement of SALLJ in February and December when compared with January has been noted. The Grell and Emanuel schemes simulated this observed oscillation in the low-level flow. However, the spatial pattern and intensity of rainfall and circulation anomalies simulated by the Grell scheme are closer to the analyses than those obtained with the Emanuel scheme.  相似文献   

Inversion of nuclear well-logging data using neural networks   总被引：1，自引：1，他引：1  

Elsa Aristodemou  Christopher Pain  Cassiano de Oliveira  Tony Goddard  Christopher Harris 《Geophysical Prospecting》2005,53(1):103-120

This work looks at the application of neural networks in geophysical well‐logging problems and specifically their utilization for inversion of nuclear downhole data. Simulated neutron and γ‐ray fluxes at a given detector location within a neutron logging tool were inverted to obtain formation properties such as porosity, salinity and oil/water saturation. To achieve this, the forward particle‐radiation transport problem was first solved for different energy groups (47 neutron groups and 20 γ‐ray groups) using the multigroup code EVENT. A neural network for each of the neutron and γ‐ray energy groups was trained to re‐produce the detector fluxes using the forward modelling results from 504 scenarios. The networks were subsequently tested on unseen data sets and the unseen input parameters (formation properties) were then predicted using a global search procedure. The results obtained are very encouraging with formation properties being predicted to within 10% average relative error. The examples presented show that neural networks can be applied successfully to nuclear well‐logging problems. This enables the implementation of a fast inversion procedure, yielding quick and reliable values for unknown subsurface properties such as porosity, salinity and oil saturation.  相似文献   

Mercury in itabirite-hosted soft hematite ore in the Quadrilátero Ferrífero of Minas Gerais     

Alexandre Raphael Cabral  Orlando Garcia Rocha Filho  Richard David Jones 《Journal of Geochemical Exploration》2008,96(1):69-76

Mercury contents in Precambrian banded iron formation-hosted hematite ores are virtually unknown. In an attempt to provide information on the abundance and distribution of Hg in Fe ore, we present analyses for Hg in samples of high-grade soft hematite ore from Gongo Soco, Minas Gerais, Brazil. Bulk samples contain from <  5 to 25  ppb Hg without obvious correlation with major elements. Granulometric fractions of follow-up samples have amounts of Hg from 6 to 48  ppb and display positive linear correlations with total Mn as MnO (r = 0.87), LOI (r = 0.87) and SiO₂ (r = 0.76), as well as a negative linear correlation with total Fe as Fe₂O₃ (r = −  0.87). The correlations suggest that Hg is associated with a hydrated ferruginous groundmass bearing residual Mn, Al and Si, which replaced gangue minerals in itabirite in the process of formation of the Gongo Soco soft hematite ore.  相似文献   

Future surface temperature changes for the Iberian Peninsula according to EURO-CORDEX climate projections     

Carvalho  D.  Cardoso Pereira  S.  Rocha  A. 《Climate Dynamics》2021,56(1-2):123-138

Climate Dynamics - Future changes in the mean, maximum and minimum temperature in the Iberian Peninsula were investigated using bias-corrected EURO-CORDEX climate projections. The results show that...  相似文献   

Using a regional frequency analysis approach for calculating the Standardized Precipitation Index: an operational approach based on the two-parameter gamma distribution     

dos Santos Junior  Edimar Pereira  Xavier  Ana Carolina Freitas  Martins  Letícia Lopes  da Rocha Sobierajski  Graciela  Blain  Gabriel Constantino 《Theoretical and Applied Climatology》2022,148(3-4):1199-1216

Theoretical and Applied Climatology - The Standardized Precipitation Index (SPI) is a worldwide used probability-based drought index. Considering that the two-parameter gamma distribution (gam) is...  相似文献   

Agrometeorological models for forecasting the qualitative attributes of “Valência” oranges     

Victor?Brunini?MoretoEmail author  Glauco?de Souza?Rolim  Bruno?Gustavo?Zacarin  Ana?Paula?Vanin  Leone?Maia?de?Souza  Rodrigo?Rocha?Latado 《Theoretical and Applied Climatology》2017,130(3-4):847-864

Forecasting is the act of predicting unknown future events using available data. Estimating, in contrast, uses data to simulate an actual condition. Brazil is the world’s largest producer of oranges, and the state of São Paulo is the largest producer in Brazil. The “Valência” orange is among the most common cultivars in the state. We analyzed the influence of monthly meteorological variables during the growth cycle of Valência oranges grafted onto “Rangpur” lime rootstocks (VACR) for São Paulo, and developed monthly agrometeorological models for forecasting the qualitative attributes of VACR in mature orchard. For fruits per box for all months, the best accuracy was of 0.84 % and the minimum forecast range of 4 months. For the relation between °brix and juice acidity (RATIO) the best accuracy was of 0.69 % and the minimum forecast range of 5 months. Minimum, mean and maximum air temperatures, and relative evapotranspiration were the most important variables in the models.  相似文献   

Combining coastal geoscience mapping and photogrammetric surveying in maritime environments (Northwestern Iberian Peninsula): focus on methodology     

Ana Pires  Helder I. Chaminé  Francisco Piqueiro  Augusto Pérez-Alberti  Fernando Rocha 《Environmental Earth Sciences》2016,75(3):196

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