On the significance of the climate-dataset time resolution in characterising wind-driven rain and simultaneous wind pressure. Part II: directional analysis     

Pérez-Bella  José M.  Domínguez-Hernández  Javier  Cano-Suñén  Enrique  del Coz-Díaz  Juan J.  Álvarez Rabanal  Felipe P. 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(6):1799-1815

Both semi-empirical methods and CFD simulations use real climate datasets as a basis for determining the building facade exposure to wind-driven rain and simultaneous wind pressure. The time resolution of these datasets and the number of variables considered (commonly rainfall intensity, wind speed and wind direction) determine the required calculation effort and the accuracy of the result. Omitting the wind direction, a former article (Part I of this research) has analysed the effect of this time resolution on two scalar exposure indices obtained by semi-empirical methods: driving rain index (aDRI) and driving-rain wind pressure (DRWP). However, the wind direction during precipitation events also causes significant exposure variations between possible facade orientations. Thus, it is also necessary to clarify the influence of the time resolution of the dataset, on the accuracy of the directional semi-empirical calculation of aDRI and DRWP. To meet this challenge, the article examines 10-min climate records collected between 2001 and 2016 at 6 Spanish locations, uses them to obtain hourly, daily, monthly and annual datasets, and analyses the accuracy of the directional exposure indices associated with each time resolution. The results show that a daily dataset would allow identifying the most exposed orientation with an error less than 45°. However, even the hourly datasets cause errors close to 10% in the exposure values identified on each facade orientation. Finally, adjustment relationships that allow estimating the maximum value of directional exposure from simple scalar indices are obtained.

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Comparing ARIMA and computational intelligence methods to forecast daily hospital admissions due to circulatory and respiratory causes in Madrid   总被引：1，自引：0，他引：1  

Ricardo?Navares  Julio?Díaz  Cristina?Linares  José?L.?AznarteEmail author 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(10):2849-2859

Anticipating future workloads in a hospital may be of capital importance in order to distribute resources and improve patient attention. In this paper, we tackle the problem of predicting daily hospital admissions in Madrid due to circulatory and respiratory cases based on biometeorological indicators. A range of forecasting algorithms were proposed covering four model families: ensemble methods, boosting methods, artificial neural networks and ARIMA. Experiments show how the last two obtain better results in average, demonstrating that the problem can be properly solved with both approaches. Furthermore, a recently proposed technique known as stacked generalization was also used to dynamically combine the predictions from the four models, finally improving the performance with respect to the individual models.  相似文献   

Allogenic and autogenic effects on mangrove dynamics from the Ceará Mirim River,north‐eastern Brazil,during the middle and late Holocene          下载免费PDF全文

Samuel Rodrigues Ribeiro  Edson José Louzada Batista  Marcelo C.L. Cohen  Marlon Carlos França  Luiz C.R. Pessenda  Neuza A. Fontes  Igor C.C. Alves  José A. Bendassolli 《地球表面变化过程与地形》2018,43(8):1622-1635

It is possible that climate changes and sea level fluctuations (allogenic processes) are and will cause major changes in mangrove dynamics. However, other driving forces may be significantly affecting this system. Distinguishing allogenic and autogenic influence on mangroves is a challenging question, because mechanisms related to the natural dynamics of depositional environments (autogenic processes) have strong influences on the establishment and degradation of mangroves. Thus, impacts on mangroves caused by autogenic processes may be erroneously attributed to allogenic mechanisms. Therefore, it is imperative to identify the ‘fingerprint’ of global changes in modern mangrove dynamics. In order to characterize the influence of these forces on mangroves, this work has used geomorphology and vegetation maps integrated with sedimentological and palynological data, radiocarbon dating, as well as δ¹³C, δ¹⁵N and C/N from sedimentary organic matter. The inter‐proxy analyses reveal an estuarine influence with mangrove development along the Ceará Mirim River, north‐eastern Brazil, since ~6920 cal yr bp , after the post‐glacial sea level rise. Relative sea level (RSL) has been stable during the middle and late Holocene. Mangrove establishment along this fluvial valley begins at about 6920 cal yr bp , caused by the sea‐level stabilization, an allogenic influence. However, after its establishment, wetland dynamics were mainly controlled by autogenic factors, related to channel migrations, instead of allogenic process. Some influence of sea‐level and climate changes on mangrove dynamics in this estuarine channel have been weakened by more intense tidal channels activities. Therefore, the expansion and contraction of mangrove areas along the estuary of the Ceará Mirim River since 6920 cal yr bp has been mainly influenced by channel dynamics that regulate the accretion and erosion of mangrove substrates. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

Non-stationary future return levels for extreme rainfall over Extremadura (southwestern Iberian Peninsula)     

Francisco Javier Acero  Sylvie Parey  Thi Thu Huong Hoang  Didier Dacunha-Castelle  José Agustín García  María Cruz Gallego 《水文科学杂志》2017,62(9):1394-1411

Based on a previous study for temperature, a new method for the calculation of non-stationary return levels for extreme rainfall is described and applied to Extremadura, a region of southwestern Spain, using the peaks-over-threshold approach. Both all-days and rainy-days-only datasets were considered and the 20-year return levels expected in 2020 were estimated taking different trends into account: first, for all days, considering a time-dependent threshold and the trend in the scale parameter of the generalized Pareto distribution; and second, for rainy days only, considering how the mean, variance, and number of rainy days evolve. Generally, the changes in mean, variance and number of rainy days can explain the observed trends in extremes, and their extrapolation gives more robust estimations. The results point to a decrease of future return levels in 2020 for spring and winter, but an increase for autumn.  相似文献   

Exploring suspended sediment delivery dynamics of two Mediterranean nested catchments   总被引：2，自引：0，他引：2       下载免费PDF全文

José A. López‐Tarazón  Joan Estrany 《水文研究》2017,31(3):698-715

This paper investigates suspended sediment transport and dynamics of two nested agricultural lowland Mediterranean catchments with a difference of two orders of magnitude in the surface area (i.e., 1 and 264 km²). The effects of the drainage catchment area over the specific suspended sediment yield are assessed by using the nested approach over various timeframes. A detailed analysis of the rainfall–runoff–sediment transport relationships during the 2‐year study period shows that the hydrological and sedimentological responses were extremely variable for both catchments. Very low or no correlations were observed between the rainfall intensity and the selected hydrological variables and sediment loads. However, remarkable or high correlations were obtained between the rainfall intensity and the maximum and average suspended sediment concentrations, indicating that rainfall per unit time has little control on the hydrological response, but that, simultaneously, its high‐erosive power triggers sediment production, increasing the sedimentary response of the catchments. This study also illustrates how sediment is mainly transported during floods, producing predominantly clockwise hysteretic loops. Moreover, the small headwater catchment exerts a reduced (or even negligible) effect over the hydro‐sedimentary response of the larger downstream catchment, caused by the reduced sediment availability in a landscape with an inherent disconnection of the sediment pathways.  相似文献   

A detailed paleomagnetic and rock-magnetic investigation around Cretaceous-Paleogene boundary: the Autlan (Western Mexico) volcanic sequence revisited     

Miguel Cervantes-Solano  Lisa Kapper  Avto Goguitchaichvili  Vicente Carlos Ruiz-Martínez  José Rosas-Elguera  Juan Morales  Rafael Maciel-Peña  Rubén Cejudo-Ruiz 《Studia Geophysica et Geodaetica》2017,61(2):233-248

We present a detailed rock-magnetic and paleomagnetic survey from Autlan volcanic succession in western Mexico. The principal aim of this study is to extend paleomagnetic data from Autlan lavas in order to confirm vertical-axis rotation observed in reconnaissance study and to evaluate long-term variation of the geomagnetic field strength based on existing and global data. The mean inclination (44.7°) is in agreement with the expected inclination for 60 and 70 Ma, as derived from available reference poles for the North American craton. The declination (333.6°), however, is significantly different from those expected, which suggests a statistically significant counterclockwise tectonic rotation ranging between 10° ± 6° and 14° ± 7°. As a measure of paleosecular variation (PSV), we obtained a geomagnetic field dispersion of 9.6° (upper and lower limits: 7.2°–11.9°) in perfect agreement with the previously published PSV compilation of selected Cretaceous data from lavas. The mean virtual dipole moments available for Autlan lavas are about 65% of the present geomagnetic axial dipole but are in reasonably good agreement with other comparable quality determinations between 5 and 90 Ma. This reinforces the hypothesis that low geomagnetic field strengths persisted for the entire Jurassic extending into the Upper Cretaceous.  相似文献   

Rock-magnetic and paleomagnetic survey on dated lava flows erupted during the Bruhnes and Matuyama chrons: the Mascota Volcanic Field revisited (Western Mexico)     

Rafael García-Ruiz  Avto Goguitchaichvili  Miguel Cervantes-Solano  Juan Morales  Rafael Maciel-Peña  José Rosas-Elguera  Ruben Cejudo-Ruiz  Jaime Urrutia-Fucugauchi 《Studia Geophysica et Geodaetica》2017,61(2):249-263

A rock magnetic and paleomagnetic investigation was performed on some selected, radiometrically dated lava flows from the Mascota Volcanic Field (MVF), western Trans- Mexican Volcanic Belt. A set of rock-magnetic experiments and standard paleomagnetic analysis were carried out on 19 sites spanning the time interval from 2268 to 72 kyr. The paleomagnetic directions are anchored to absolute radiometric ages while no such information was available in previous studies. This makes possible to correctly evaluate the fluctuation of Earth’s magnetic field from Pliocene to Pleistocene and reveal the firm evidence of possible Levantine excursion. Both Ti-poor and Ti-rich titanomagnetites seem to carry the remanent magnetization with Curie temperatures ranging from 350°C to 537°C. Thirteen flows correspond to the Brunhes chron, one of them exhibits transitional directions, while the remaining six sites belong to the Matuyama chron. New and existing dataset for MVF were used to estimate the paleosecular variation parameters. The selected data include 35 Plio-Quaternary lava flows. After excluding the poor quality data, as well as the transitional directions, the mean paleodeclination is 356.1° and oaleoinclination 39.9°, which agree well with the geocentric axial dipole (GAD) and the expected paleodirections for the Plio-Pleistocene, as derived from the reference poles for the stable North America. The corresponding mean paleomagnetic poles are paleolongitude 226.7° and paleolatitude 86.0°. The virtual geomagnetic pole scatter for the MVF is 15.2°, which is consistent with the value expected from model G at latitude of 20° (this model provides an interpretation of the paleosecular variation at different latitudes for the time of interest). The combined paleomagnetic data, supported by positive reversal test, indicate no paleomagnetically detectable vertical-axis rotations in the study area. The evidence of one transitional directions was detected, which may correspond to the Levantine excursion (360-370 kyr) or unnamed event between 400-420 kyr.  相似文献   

Content analysis of dam break studies for tailings dams with high damage potential in the Quadrilátero Ferrífero,Minas Gerais: technical weaknesses and proposals for improvements     

de Paiva  Camilla Adriane  da Fonseca Santiago  Aníbal  do Prado Filho  José Francisco 《Natural Hazards》2020,104(2):1141-1156

Natural Hazards - Tailings dams are civil structures that have an intrinsic potential risk of failure that, if poorly managed or neglected, can lead to severe societal, environmental, and economic...  相似文献   

Geophysical investigation of the Colônia structure,Brazil     

Renato L. Prado  Isabel C. Espin Fenoll  Irfan Ullah  Gianna C. Maciel Miura  Alvaro P. Crsta  Roberto P. Zanon dos Santos  Wolf Uwe Reimold  Vagner R. Elis  Erico Imbernon  Claudio Riccomini  Liliana Alcazar Diogo 《Meteoritics & planetary science》2019,54(10):2357-2372

The origin of the nearly circular Colônia structure, located at the southwestern edge of the city of São Paulo, Brazil, has been the subject of a long‐standing debate, ever since the 1960s when the structure was first investigated by geophysical methods. The structure still raises interest for geological research, as its sedimentary infill holds important paleoclimatic information about the evolution of the tropical rainforest, as well as the interplay between the South American summer monsoon, the Intertropical Convergence Zone, and the southern Westerly wind belt—for possibly as long as several million years. In addition, the search for evidence to conclusively establish the origin of this structure continues, and the answer most likely lies in the lower portions of the basin's sedimentary infill, which also holds a significant potential for underground water resources. Here, we present the results from recent seismic (reflection and HVSR), gravimetric, and geoelectrical surveys. They have provided a reliable image of the sedimentary infill, and the maximum depth to basement within the structure has been constrained consistently by the different methods to approximately ?400 m. The geophysical data have also allowed to map the lateral contact between the crystalline basement rocks and the sedimentary infill, which indicates a diameter of approximately 2.8 km for the sedimentary basin, with 3.6 km being the diameter of the outermost limit of the structure. A total of six seismic stratigraphic boundaries were identified within the sedimentary infill, providing a framework for the planning of a deep drilling campaign and subsequent sampling program aimed at geological and paleoclimatology studies.  相似文献   

Drought regulates the burned forest areas in Mexico: the case of 2011, a record year     

José Manuel Zúñiga-Vásquez  Dario Cisneros-González 《国际地球制图》2019,34(5):560-573

During 2011, Mexico experienced record figures in terms of forest fires, with an affected area of 956,405 ha, and an association between this activity and the meteorological conditions is suspected. We addressed the question: Are the burned areas in Mexico associated with the duration and accumulation of drought? Using the G statistic, the cluster zones of burned areas in Mexico in 2011 were analyzed, and the value of accumulated drought that was most related to these cluster zones was determined. Global and local regression models were used to evaluate the drought-burned areas association. Two cluster zones were found (zones A and B). Accumulated drought of 24 and 12 months significantly explained the burned areas of zones A and B, respectively. The burned areas of Mexico in 2011 were non-randomly distributed, and accumulated drought significantly explained the magnitude of the areas affected by fire.  相似文献