Exploring the interactions between vulnerability,resilience and adaptation to extreme temperatures     

Nunes  Ana Raquel 《Natural Hazards》2021,109(3):2261-2293

Natural Hazards - Proposed ways of improving adaptation to climate change have most often been supported by narrowly framed and separate analysis. This article investigates how different levels of...  相似文献   

Capability of LISEM to estimate flood hydrographs in a watershed with predominance of long-duration rainfall events     

Vargas  Marcelle Martins  Beskow  Samuel  de Mello  Carlos Rogério  de Moura  Maíra Martim  Nunes  Maria Cândida Moitinho  Faria  Lessandro Coll  Aquino  Leandro Sanzi 《Natural Hazards》2021,109(1):593-614

Natural Hazards - Process-based hydrological models are of great importance to understand hydrological processes and support decision making. The LImburg Soil Erosion Model (LISEM) requires...  相似文献   

A combined structural and seasonal approach to assess wildfire susceptibility and hazard in summertime     

Bergonse  Rafaello  Oliveira  Sandra  Gonçalves  Ana  Nunes  Sílvia  da Câmara  Carlos  Zêzere  José Luis 《Natural Hazards》2021,106(3):2545-2573

Natural Hazards - Wildfire susceptibility and hazard models based on drivers that change only on a multiyear timescale are considered of a structural nature. They ignore specific short-term...  相似文献   

Geostatistical Seismic Inversion with Self-Updating of Local Probability Distributions     

Azevedo  Leonardo  Narciso  João  Nunes  Rúben  Soares  Amílcar 《Mathematical Geosciences》2021,53(5):1073-1093

Mathematical Geosciences - Three-dimensional subsurface elastic models inverted from seismic reflection data are the basis of the geo-modeling workflow. These models are often used to predict the...  相似文献   

Beta diversity of pelagic assemblages at fish aggregating devices in the open ocean     

F Forget  L Dagorn  B Mérigot  JC Gaertner  J Robinson  PD Cowley 《African Journal of Marine Science》2020,42(2):247-254

Owing to difficulties in accessing the vast open ocean, the beta (β) diversity of pelagic fish assemblages remains poorly studied. We investigated the relationship between assemblage similarity and geographical distance between anchored fish aggregating devices (FADs), sampled by standardised underwater visual censuses in three anchored FAD arrays in the Indian Ocean—at the Maldives, the Seychelles and Mauritius. The use of two complementary indices of β-diversity, based on presence/absence data (Jaccard similarity coefficient) and abundance data (Bray–Curtis index), revealed that geographical distance between sampling sites (from 4 to 257 km) appeared to have no effect on the similarity of fish assemblages associated with FADs within each array. The results of this preliminary study question the generalisation of the paradigm of an increase in β-diversity with geographic distance to the open-ocean fish community. Large-scale studies using a variety of datasets should be conducted to further investigate patterns of β-diversity in the open ocean.  相似文献   

Numerical modeling of surface runoff and erosion due to moving rainstorms at the drainage basin scale   总被引：1，自引：0，他引：1  

J.P. Nunes  J.L.M.P. de Lima  V.P. Singh  M.I.P. de Lima  G.N. Vieira 《Journal of Hydrology》2006,330(3-4):709-720

A physically-based distributed erosion model (MEFIDIS) was applied to evaluate the consequences of storm movement on runoff and erosion from the Alenquer basin in Portugal. Controlled soil flume laboratory experiments were also used to test the model. Nine synthetic circular storms were used, combining three storm diameters (0.5, 1 and 2 times the Alenquer basin’s axial length) with three speeds of storm movement (0.5, 1 and 2 m/s); storm intensities were synthesized in order to maintain a constant rainfall depth of 50 mm. The model was applied to storms moving downstream as well as upstream along the basin’s axis. In all tests, downstream-moving storms caused significantly higher peak runoff (56.5%) and net erosion (9.1%) than did upstream-moving storms. The consequences for peak runoff were amplified as the storm intensity increased. The hydrograph shapes were also different: for downstream-moving storms, runoff started later and the rising limb was steeper, whereas for upstream moving storms, runoff started early and the rising limb was less steep. Both laboratory and model simulations on the Alenquer basin showed that the direction of storm movement, especially in case of extreme rainfall events, significantly affected runoff and soil loss.  相似文献   

A U-Pb zircon,and Rb-Sr and U-Th-Pb whole-rock study of a polymetamorphic terrane in the central Alps,Switzerland     

P. D. Nunes  Prof. Dr. R. H. Steiger 《Contributions to Mineralogy and Petrology》1974,47(4):255-280

U-Pb analyses of zircons from the southern paragneiss zone of the Gotthard massif in the central Alps indicate these rocks were derived from one or more source areas ≧ 1400 m.y. old and were strongly affected by both the Caledonian and Hercynian orogenies. Rb-Sr whole-rock analyses also appear to reflect the Hercynian event while Rb-Sr analyses of a metamorphic inclusion and a boudin indicate that these small-scale samples were affected by the Alpine orogeny. U-Pb whole rock data appear to reflect only the Hercynian event; these data, when corrected for primordial lead, furthermore yield an upper concordia intercept of 4500 m.y., possibly resulting from a U-Pb fractionation very early in the history of the earth. A more refined three-stage U-Pb evolution model yields an age of about 4480 m.y. rather than 4500 m.y. for this hypothesized early terrestrial differentiation. Geologically these data emphasize that: 1) the southern paragneiss zone of the Gotthard massif contains metasediments which have experienced the Caledonian orogeny and are at least 400 m.y. old; 2) the Hercynian episode in this region was pervasive indeed; and 3) the Alpine orogeny affected the Rb-Sr and U-Pb whole rock systems to a far lesser degree than the preceding orogenic episodes and apparently did not affect the U-Pb zircon systems investigated at all.  相似文献   

Impacts of land-use and climate changes on surface runoff in a tropical forest watershed (Brazil)     

Manuel Esteban Lucas-Borja  Bruno Gianmarco Carrà  João Pedro Nunes  Léonard Bernard-Jannin  Santo Marcello Zimbone 《水文科学杂志》2020,65(11):1956-1973

ABSTRACT

Surface runoff generation capacity can be modified by land-use and climate changes. Annual runoff volumes have been evaluated in a small watershed of tropical forest (Brazil), using the Soil and Water Assessment Tool (SWAT) model. Firstly, the accuracy of SWAT in runoff predictions has been assessed by default input parameters and improved by automatic calibration, using 20-year observations. Then, the hydrological response under land uses (cropland, pasture and deforested soil) alternative to tropical forest and climate change scenarios has been simulated. SWAT application has showed that, if forest was replaced by crops or pasture, the watershed’s hydrological response would not significantly be affected. Conversely, a complete deforestation would slightly increase its runoff generation capacity. Under forecasted climate scenarios, the runoff generation capacity of the watershed will tend to decrease and will not be noticeably different among the representative concentration pathways. Pasture and bare soil will give the lowest and highest runoff coefficients, respectively.  相似文献   

Orographical modification and large scale forcing of a cold front     

Dr. K. Keuler  PD Dr. J. Kerkmann  Prof. Dr. H. Kraus  PD Dr. E. Schaller 《Meteorology and Atmospheric Physics》1992,48(1-4):105-130

Summary The development of a cold front influenced by orography and large scale forcing is examined with a two-dimensional meso-scale model. The model is based on the primitive equations and uses the hydrostatic and anelastic approximations. Gradients of the basic flow and temperature field in the third dimension are taken into account during the simulations. Low diffusive numerical schemes and radiation boundary conditions reduce the numerical errors to an acceptable minimum for a two day simulation and avoid reflections at the upper and lateral boundaries. Frontogenetical forcing is included in the simulations by specifying either a vertically sheared or horizontally convergent basic zonal flow field. Model runs with an idealized cold front were carried out over flat terrain and in the presence of a bell shaped mountain ridge.The simulations show a weakening of the cold front on the windward side of the mountain ridge and a strong reintensification on the leeward side relative to the control runs without topography. Analysis of frontogenesis terms demonstrates the importance of convergence in the ageostrophic circulation and of along-front temperature advection for the development of the cold front. The strong intensification of the cold front on the leeward side of the mountain ridge can only partly be explained by superposition with the mountain induced wave. It is mainly caused by ageostrophic deformation forcing in the strong downward flow of this wave.The results also show that the cold front passage over the mountain ridge is not a continuous process. The formation of a new frontal structure on the leeward side of the mountain ridge, well separated from the primary one, is observed while the initial cold front still exists in the upslope region. Generally nonlinear interactions between the mountain wave and the cold front are the important mechanisms to explain these phenomena.With 18 Figures  相似文献   

Magnetic Basement Depth Inversion in the Space Domain     

Tiago Mane Nunes  Valéria Cristina F. Barbosa  João Batista C. Silva 《Pure and Applied Geophysics》2008,165(9-10):1891-1911

We present a total-field anomaly inversion method to determine both the basement relief and the magnetization direction (inclination and declination) of a 2D sedimentary basin presuming negligible sediment magnetization. Our method assumes that the magnetic intensity contrast is constant and known. We use a nonspectral approach based on approximating the vertical cross section of the sedimentary basin by a polygon, whose uppermost vertices are forced to coincide with the basin outcrop, which are presumably known. For fixed values of the x coordinates our method estimates the z coordinates of the unknown polygon vertices. To obtain the magnetization direction we assume that besides the total-field anomaly, information about the basement’s outcrops at the basin borders and the basement depths at a few points is available. To obtain stable depth-to-basement estimates we impose overall smoothness and positivity constraints on the parameter estimates. Tests on synthetic data showed that the simultaneous estimation of the irregular basement relief and the magnetization direction yields good estimates for the relief despite the mild instability in the magnetization direction. The inversion of aeromagnetic data from the onshore Almada Basin, Brazil, revealed a shallow, eastward-dipping basement basin.  相似文献