Fundacao Cearense de Meteorologia e Recursos Hidricos

Fortaleza, Brazil

Fundacao Cearense de Meteorologia e Recursos Hidricos

Fortaleza, Brazil
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Vieira R.M.S.P.,National Institute for Space Research | Tomasella J.,National Institute for Space Research | Sestini M.F.,National Institute for Space Research | Affonso A.G.,National Institute for Space Research | And 9 more authors.
Solid Earth | Year: 2015

Approximately 57% of the Brazilian northeast region is recognized as semi-arid land and has been undergoing intense land use processes in the last decades, which have resulted in severe degradation of its natural assets. Therefore, the objective of this study is to identify the areas that are susceptible to desertification in this region based on the 11 influencing factors of desertification (pedology, geology, geomorphology, topography data, land use and land cover change, aridity index, livestock density, rural population density, fire hot spot density, human development index, conservation units) which were simulated for two different periods: 2000 and 2010. Each indicator were assigned weights ranging from 1 to 2 (representing the best and the worst conditions), representing classes indicating low, moderate and high susceptibility to desertification. The results indicate that 94% of the Brazilian northeast region is under moderate to high susceptibility to desertification. The areas that were susceptible to soil desertification increased by approximately 4.6% (83.4 km2) from 2000 to 2010. The implementation of the methodology provides the technical basis for decision-making that involves mitigating actions and the first comprehensive national assessment within the United Nations Convention to Combat Desertification framework. © Author(s) 2015.

Campos J.N.B.,Federal University of Ceará | Silveira C.S.,University da Integracao Internacional da Lusofonia Afro Brasileira | Pereira J.M.R.,Fundacao Cearense de Meteorologia e Recursos Hidricos
Revista Brasileira de Meteorologia | Year: 2016

This paper presents an evaluation of the climate forecast in the upper valley of the river Jaguaribe, State of Ceara-Brazil. The forecast was performed using the global circulation model (ECHAM 4.5) boundary conditions to the regional model (RAMS 6.0). The model simulates the monthly scale rainfall in order to aggregate it in the regional rainy season (January to June). We used the Heidke Skill Score (HSS) as a metric of forecast skill. The simulations were performed for the wet season, covering the period from 1979 to 2010. The HSS was calculated for intervals of 1, 2, 10, 15, 21, 30, 45, 60, 120 and 180 days in order to find the Time Interval of Maximum Predictability (ITEMP). The obtained curve, HSSvs.time, presented a maximum HSS of 0.62 for 45 days. This result indicates that climate prediction even with its limitations (initial data of soil moisture and used parameterization) could be an important tool for the reservoir management in Brasilian Semiarid region. © 2016, Sociedade Brasileira de Meteorologia. All Rights reserved.

Martins R.C.G.,Fundacao Cearense de Meteorologia e Recursos Hidricos | Costa A.A.,State University of Ceará
Atmospheric Research | Year: 2010

This work presents a characterization of the Amazonian precipitation diurnal cycle through an analysis of radar reflectivity profiles and drop-size distributions attained respectively from a microwave vertical profiler and a disdrometer during the 1999 WET-AMC experiment. In such analysis, precipitation was split in time and classes, which provided information on the daily variation of typical reflectivity profiles and the raindrop spectra associated with them. A clear signature of the diurnal cycle can be observed in the radar profiles and in the raindrop size distribution; for instance, the stratiform rainfall is dominant in the period of 03:00 to 09:00 LST showing the collapse of the convective structures dominant during the afternoon. The time interval centered at 21:00 LST shows the collapse of the ice phase and convective activity, typical of the transition from convective to stratiform precipitation. The size distribution and the reflectivity profiles also depend on the rainfall intensity. The combined analysis of the diurnal cycle and rainfall intensity shows interesting features of the cloud life cycle over the Amazon region, including the initiation of ice and the establishment of the bright band. Statistical analysis revealed that most RDSDs exhibit a single peak around 0.5. mm (48.9%), 1.0. mm (30.7%) or 2.0. mm (2.5%) and that only a few are effectively bimodal, which permitted the use of gamma distributions to fit most of the observed raindrop spectra. © 2010 Elsevier B.V.

da Silva R.R.,Federal University of Santa Catarina | Gandu A.W.,Fundacao Cearense de Meteorologia e Recursos Hidricos | Cohen J.C.,Federal University of Pará | Kuhn P.,Federal University of Amazonas | Mota M.A.,Federal University of Pará
Revista Brasileira de Meteorologia | Year: 2014

The OLAM model has as its characteristics the advantage to represent simultaneously the global and regional meteorological phenomena using the application of a grid refinement scheme. During the REMAM project the model was applied for a few case studies to evaluate its performance on numerical weather prediction for the eastern Amazon region. Case studies were performed for the twelve months of the year of 2009. The model results for those numerical experiments were compared with the observed data for the region of study. Precipitation data analysis showed that OLAM is able to represent the average mean accumulated precipitation and the seasonal features of the events occurrence, but can’t predict the local total amount of precipitation. However, individual evaluation for a few cases had shown that OLAM was able to represent the dynamics and forecast a few days in advance the development of coastal meteorological systems such as the squall lines that are one of the most important precipitating systems of the Amazon. © 2014, Sociedade Brasileira de Meteorologia. All rights reserved.

Montade V.,Fundacao Cearense de Meteorologia e Recursos Hidricos | Montade V.,CNRS Montpellier Institute of Evolutionary Sciences | Ledru M.-P.,CNRS Montpellier Institute of Evolutionary Sciences | Burte J.,Center de Cooperation Internationale en Recherche Agronomique pour le Developpement | And 4 more authors.
Journal of Biogeography | Year: 2014

Aim: The primary objectives of this study were (1) to assess, in the light of palaeoecological reconstruction, the climate stability hypothesis used by evolutionary biologists to explain high diversity in historically stable areas, and (2) to identify the response mechanisms of a tropical rain forest microrefugium to climatic variability. Location: North-eastern Brazil, Serra de Maranguape. Methods: Vegetation and climatic changes were reconstructed using a pollen record in a sediment core from a forest hollow, and the chronology was based on accelerator mass spectrometry radiocarbon analyses. Results: Past vegetation dynamics consisted of three main forest types, shown by major compositional changes in rain forest assemblages between 5000 and 1000 cal. yr bp. Dense ombrophilous forest was abruptly replaced by heliophilous early successional tree taxa at 4275 cal. yr bp. These early successional tree taxa were established over a period of c. 100 years, and their dominance lasted for c. 750 years and was associated with dry conditions until 3525 cal. yr bp. Subsequently, the expansion of secondary successional tree taxa over a period of c. 550 years enabled the recovery of ombrophilous forest. Main conclusions: The vegetation changes in the Serra de Maranguape provide evidence for the high sensitivity of this rain forest microrefugium to climatic variability on a multidecadal to millennial time-scale during the mid- to late Holocene. Despite the substantial compositional and climatic changes, this microrefugium apparently was continuously forested and responded to climatic instability by recruiting key species to its highly diverse stock. This evidence helps to address the joint concerns of evolutionary biologists and palaeoecologists regarding how forests can persist during periods of climatic variability by showing that some tropical regions can remain continuously forested despite reorganization during abrupt and short-term climatic changes. © 2014 John Wiley & Sons Ltd.

Montade V.,Montpellier University | Montade V.,EPHE Paris | Montade V.,University of Gottingen | Diogo I.J.S.,University of Campinas | And 10 more authors.
Review of Palaeobotany and Palynology | Year: 2016

Surface soil samples were collected in three mountainous massifs in north-eastern Brazil to characterize the different vegetation types according to their respective pollen assemblages. Complementary approach between pollen and vegetation data shows that the pollen rain accurately reflects the following three main forest types: i) a dense ombrophilous forest (or tropical moist broadleaf forest) characterized by Myrtaceae associated with high percentages of Miconia, Guapira, Ilex, Moraceae-Urticaceae undif. or Byrsonima, ii) a seasonal semi-deciduous montane forest characterized by an increase of Arecaceae associated with Fabaceae-Mimosideae, Myrtaceae, Piper, Cecropia, Urera and Mitracarpus, and iii) a seasonal deciduous forest dominated by Fabaceae-Mimosideae and Arecaceae tree taxa associated with Alternanthera, Cyperaceae and Mitracarpus. Using of botanical data from several plots of ombrophilous forest, in which several surface soil samples have been collected, allows to roughly estimate the over- and underrepresentation of pollen taxa relative to their floristic abundance. Furthermore, distribution of surface soil samples at different altitude and mountain sides also allows to characterize vegetation variation according to several environmental parameters. The precipitation increase with altitude is confirmed as the main environmental factor controlling vegetation distribution. However, the forests located close to the crest with a proportion increase of pollen taxa characteristic of heliophilous and pioneer trees (Alchornea, Miconia, Clusia), are also influenced by changes of edaphic conditions. In addition to provide useful information in understanding of fossil pollen records, this approach improves our understanding of the ecosystem functioning in mountainous massifs in north-eastern Brazil. A useful knowledge for conservation or restoration purposes. © 2016 Elsevier B.V.

Geraldo-Ferreira A.,Fundacao Cearense De Meteorologia e Recursos Hidricos | Geraldo-Ferreira A.,University of Valencia | Soria-Olivas E.,University of Valencia | Gomez-Sanchis J.,University of Valencia | And 3 more authors.
Expert Systems with Applications | Year: 2011

The knowledge of net radiation at the surface is of fundamental importance because it defines the total amount of energy available for the physical and biological processes such as evapotranspiration, air and soil warming. It is measured with net radiometers, but, the radiometers are expensive sensors, difficult to handle, that require constant care and also involve periodic calibration. This paper presents a methodology based on neural networks in order to replace the use of net radiometers (expensive tools) by modeling the relationships between the net radiation and meteorological variables measured in meteorological stations. Two different data sets (acquired at different locations) have been used in order to train and validate the developed artificial neural model. The statistical results (low root mean square errors and mean absolute error) show that the proposed methodology is suitable to estimate net radiation at surface from common meteorological variables, therefore, can be used as a substitute for net radiometers. © 2011 Elsevier Ltd. All rights reserved.

Cohen J.C.P.,Federal University of Pará | Fitzjarrald D.R.,Albany State University | D'Oliveira F.A.F.,Federal University of Pará | Saraiva I.,Centro Regional Of Manaus | And 3 more authors.
Revista Brasileira de Meteorologia | Year: 2014

Standard Amazonian rainfall climatologies rely on stations preferentially located near river margins. River breeze circulations that tend to suppress afternoon rainfall near the river and enhance it inland are not typically considered when reporting results. Previous studies found surprising nocturnal rainfall maxima near the rivers in some locations. We examine spatial and temporal rainfall variability in the Santarém region of the Tapajós-Amazon confluence, seeking to describe the importance of breeze effects on afternoon precipitation and defining the areal extent of nocturnal rainfall maxima.We used three years of mean S band radar reflectivity from Santarém airport with a Z-R relationship appropriate for tropical convective conditions. These data were complemented by TRMM satellite rainfall estimates. Nocturnal rainfall was enhanced along the Amazon River, consistent with the hypothesis that these are associated with the passage of instability lines, perhaps enhanced by local channeling and by land breeze convergence. In the daytime, two rainfall bands appear in mean results, along the east bank of the Tapajós River and to the south of the Amazon River, respectively. © 2014, Sociedade Brasileira de Meteorologia. All rights reserved.

Guimares F.V.A.,Fundacao Cearense de Meteorologia e Recursos Hidricos | de Lacerda C.F.,Federal University of Ceará | Marques E.C.,Federal University of Ceará | de Abreu C.E.B.,Federal University of Ceará | And 3 more authors.
Brazilian Journal of Plant Physiology | Year: 2012

The growth and nutrient assimilation was evaluated in CaCl2- and CaSO4-supplemented cowpea plants subjected to salt stress (75 mM NaCl). The salinity significantly reduced the cowpea vegetative growth. The addition of CaCl2 in the growth medium did not significantly affect plant growth, while for the CaSO4, the beneficial effects of Ca2+ were moderate. Salinity increased the Na+, K+, Cl-, N and P content in the plants, however it decreased the content of Ca2+ and Mg2+. Increases in Ca2+ concentration in the nutrient solution caused decreases in the Na+ and Mg2+ contents and increases in Ca2+, K+, P, and Cl- contents. The supplemental Ca2+ may alleviate the Na+ toxicity and may improve nutritional and ionic balance in cowpea, but it cannot overcome the osmotic effects associated with the increased total salt concentration.

Guimaraes F.V.A.,Fundacao Cearense de Meteorologia e Recursos Hidricos | de Lacerda C.F.,Federal University of Ceará | Marques E.C.,Federal University of Ceará | de Miranda M.R.A.,Federal University of Ceará | And 3 more authors.
Plant Growth Regulation | Year: 2011

The effects of supplemental Ca2+ on membrane integrity and lipid composition of cowpea plants submitted to salt stress (75 mM NaCl) were evaluated. The experimental design was factorial (2 × 6+1) corresponding to six saline treatments supplemented with CaCl2 and six saline treatments supplemented with CaSO4, both at 0.5, 1.25, 2.5, 5.0, 7.5 and 10.0 mM, plus control treatment (plants grown in half-strength Hoagland's nutrient solution without supplemental calcium addition). Samples of leaves and root tips were analyzed for total lipid, glycolipid and fatty acid contents and membrane damage symptoms. Salt stress greatly reduced total lipid content in leaves and roots and caused great damage to membrane structures. In leaves, the glycolipid content was differently influenced by calcium treatments. Moreover, salinity increased the saturated/unsaturated fatty acid ratio in leaves and an increase in the concentration of calcium intensified this response. In roots, only saturated fatty acids were detected and their content was strongly influenced by salinity and very little by calcium treatments. Supplemental Ca2+ was unable to ameliorate the negative effects of salinity on the structural integrity and fluidity of plant membranes in cowpea. © 2011 Springer Science+Business Media B.V.

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