The last sunset on mainland Europe     

Jorge Mira-Pérez 《制图学和地理信息科学》2018,45(1):56-61

Certain coastal localities attempt to attract tourists by claiming to have the earliest sunrise or latest sunset in their country or even continent. This article documents the places in mainland Europe where the sun sets latest during the year. In contradiction to the naïve assumption that the sun always sets latest at the westernmost point, the point of last sunset changes cyclically over the course of a year due to the changing orientation of the axis of the Earth with respect to the sun. On mainland Europe, the focus of this study, between the winter and summer solstices the last sunset shifts successively from Cabo de São Vicente (Portugal) to Cabo da Roca (Portugal) to Cabo Touriñán (Spain) to a site near Aglapsvik (Norway) to a location in the Norwegian municipality of Måsøy south of Havøysund; and it shifts back again between the summer and winter solstices. There are even 2 days of the year (24th April and 18th August) on which the last sunset of mainland Europe coincides with the last sunset of mainland Africa, at a site in Western Sahara near Cap Blanc. A similar analysis of the first sunrise in Spain is also done.  相似文献   

A method to reconstruct flood scenarios using field interviews and hydrodynamic modelling: application to the 2017 Suleja and Tafa,Nigeria flood     

Malgwi  Mark Bawa  Ramirez  Jorge Alberto  Zischg  Andreas  Zimmermann  Markus  Schürmann  Stefan  Keiler  Margreth 《Natural Hazards》2021,108(2):1781-1805

Natural Hazards - The scarcity of model input and calibration data has limited efforts in reconstructing scenarios of past floods in many regions globally. Recently, the number of studies that use...  相似文献   

Rapid characterisation of the extremely large landslide threatening the Rules Reservoir (Southern Spain)     

Reyes-Carmona  Cristina  Galve  Jorge Pedro  Moreno-Sánchez  Marcos  Riquelme  Adrián  Ruano  Patricia  Millares  Agustín  Teixidó  Teresa  Sarro  Roberto  Pérez-Peña  José Vicente  Barra  Anna  Ezquerro  Pablo  López-Vinielles  Juan  Béjar-Pizarro  Marta  Azañón  José Miguel  Monserrat  Oriol  Mateos  Rosa María 《Landslides》2021,18(12):3781-3798

Landslides - When an active landslide is first identified in an artificial reservoir, a comprehensive study has to be quickly conducted to analyse the possible hazard that it may represent to such...  相似文献   

Transpiration in Quercus suber trees under shallow water table conditions: the role of soil and groundwater          下载免费PDF全文

Clara A. Pinto  Nadezhda Nadezhdina  Jorge S. David  Cathy Kurz‐Besson  Maria C. Caldeira  Manuel O. Henriques  Fernando G. Monteiro  João S. Pereira  Teresa S. David 《水文研究》2014,28(25):6067-6079

Water is one of the major environmental factors limiting plant growth and survival in the Mediterranean region. Quercus suber L. woodlands occupy vast areas in the Iberian Peninsula, frequently under shallow water table conditions. The relative magnitude of soil and groundwater uptake to supply transpiration is not easy to evaluate under these circumstances. We recently developed a conceptual framework for the functioning of the root system in Q. suber that simulates well tree transpiration, based on two types of root behaviour: shallow connected and deep connected. Although this significantly improved knowledge on the functional traits of Mediterranean Q. suber, the approach has the limitation of requiring root sap flow data, which are seldom available. In this work, we present alternative methodologies to assess if trees are connected to groundwater and to estimate the soil and groundwater contributions to tree transpiration. We provide evidence on the tree unrestricted access to groundwater solely based on meteorological, stem sap flow and leaf water potential data. Using a soil mass balance approach, we estimated the yearly soil and groundwater contributions to tree transpiration: 69.7% and 30.3%, respectively. Groundwater uptake became dominant in the dry summer: 73.2% of tree transpiration. Results reproduce extremely well those derived from root modelling. Because of its simplicity both in formulation and data requirements, our approach is potentially liable to be adapted to other groundwater‐dependent Mediterranean oak sites, where interactions between land use and water resources may be relevant. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Evapotranspiration models of different complexity for multiple land cover types     

Minha Choi  William P. Kustas  Ram L. Ray 《水文研究》2012,26(19):2962-2972

A comparison between half‐hourly and daily measured and computed evapotranspiration (ET) using three models of different complexity, namely, the Priestley–Taylor (P‐T), the reference Penman–Monteith (P‐M) and the Common Land Model (CLM), was conducted using three AmeriFlux sites under different land cover and climate conditions (i.e. arid grassland, temperate forest and subhumid cropland). Using the reference P‐M model with a semiempirical soil moisture function to adjust for water‐limiting conditions yielded ET estimates in reasonable agreement with the observations [root mean square error (RMSE) of 64–87 W m^?2 for half‐hourly and RMSE of 0.5–1.9 mm day^?1 for daily] and similar to the complex Common Land Model (RMSE of 60–94 W m^?2 for half‐hourly and RMSE of 0.4–2.1 mm day^?1 for daily) at the grassland and cropland sites. However, the semiempirical soil moisture function was not applicable particularly for the P‐T model at the forest site, suggesting that adjustments to key model variables may be required when applied to diverse land covers. On the other hand, under certain land cover/environmental conditions, the use of microwave‐derived soil moisture information was found to be a reliable metric of regional moisture conditions to adjust simple ET models for water‐limited cases. Further studies are needed to evaluate the utility of the simplified methods for different landscapes. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

The importance of subsurface nepheloid layers in transport and delivery of sediments to the eastern Cariaco Basin,Venezuela     

Laura Lorenzoni  Robert C Thunell  Claudia R. Benitez-Nelson  David Hollander  Nahysa Martinez  Eric Tappa  Ramón Varela  Yrene Astor  Frank E. Muller-Karger 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(12):2249-2262

Optical transmissometer measurements were coupled with particulate organic matter (POM) observations to understand suspended sediment composition and distribution in the eastern Cariaco Basin during the rainy seasons of September 2003 and 2006. Our results suggest that nepheloid layers originating at the mouth of small mountainous rivers discharging into the eastern Basin are a major delivery mechanism of terrigenous sediments to the Basin interior. Intermediate nepheloid layers (INL) were observed near the shelf break (～100 m) and appear to effectively transport terrigenous material laterally from the shelf to deep waters, thereby providing a plausible supply mechanism of the terrestrial material observed in sediment traps. These findings highlight the importance of small, local rivers in the Cariaco Basin as sources of terrestrial material. In contrast, these nepheloid layers contained only limited POM. When this information is combined with published sediment trap POM data, it suggests that nepheloid layers may not be a primary mechanism for delivering terrigenous POM to the deeper waters of the basin during the rainy season. Rather, BNL may redistribute marine-derived POM from shallow waters to the Basin's interior by providing ballast materials, particularly during episodic events driven by wind and precipitation. Though we have determined that nepheloid layers play an important role in the seaward transport of particulate material in the Cariaco Basin, their composition and temporal variability have not been fully characterized. This is critical to understand lateral particle transport, since nepheloid layers constitute a significant source of sediment to the deep Cariaco Basin.  相似文献   

Assessment of substratum effect on the distribution of two invasive Caulerpa (Chlorophyta) species     

Eduardo Infantes  Jorge Terrados  Alejandro Orfila 《Estuarine, Coastal and Shelf Science》2011,91(3):434-441

Two-year monitoring of the invasive marine Chlorophyta Caulerpa taxifolia and Caulerpa racemosa var. cylindracea shows the great influence of substratum on their spatial distribution. The cover of C. taxifolia and C. racemosa was measured in shallow (<8 m) areas indicating that these species are more abundant in rocks with photophilic algae and in the dead matte of the seagrass Posidonia oceanica than in sand or inside the P. oceanica meadow. A short-term experiment comparing the persistence of C. taxifolia and C. racemosa planted either in a model of dead matte of P. oceanica or in sand shows that the persistence of these species was higher in the dead matte model than in sand. Correlative evidence suggests that C. taxifolia and C. racemosa tolerate near-bottom orbital velocities below 15 cm s^?1 and that C. taxifolia cover declines at velocities above that value. These results contribute to understand the process of invasion of these Caulerpa species predicting which substrata would be more susceptible to be invaded and to the adoption of appropriate management strategies.  相似文献   

An improved AMC‐coupled runoff curve number model     

Ram Kumar Sahu  S. K. Mishra  T. I. Eldho 《水文研究》2010,24(20):2834-2839

In the Soil Conservation Service Curve Number (SCS‐CN) method, the three levels of antecedent moisture condition (AMC) permit unreasonable sudden jumps in curve numbers, which result into corresponding jumps in the estimated runoff. A few recently developed SCS‐CN‐based models obviate this problem, yet they have several limitations. In this study, such a model incorporating a continuous function for antecedent moisture has been presented. It has several advantages over the other existing SCS‐CN‐based models. Its application to a large dataset from US watersheds showed to perform better than the existing SCS‐CN method and the others based on it. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Concentration of Trace Metals and Biochemical Alterations in Various Species of Fishes along the West Coast of India     

Molla  Nageswar Rao  Gaud  Angad  Ram  Anirudh  Vidavalur  Siddaiah  Sudhakaran  Rakesh Payipattu  Pitchaikkaran  Raja 《Ocean Science Journal》2021,56(1):55-68

Ocean Science Journal - This study seeks to evaluate levels of seven trace metals (Cr, Mn, Fe, Cu, Zn, Pb and Hg) and biochemical (proteins, lipids and carbohydrates) alterations in muscle tissue...  相似文献   

The solar, exoplanet and cosmological lithium problems     

J. Meléndez  I. Ramírez  L. Casagrande  M. Asplund  B. Gustafsson  D. Yong  J. D. do Nascimento Jr.  M. Castro  M. Bazot 《Astrophysics and Space Science》2010,328(1-2):193-200

We review three Li problems. First, the Li problem in the Sun, for which some previous studies have argued that it may be Li-poor compared to other Suns. Second, we discuss the Li problem in planet hosting stars, which are claimed to be Li-poor when compared to field stars. Third, we discuss the cosmological Li problem, i.e. the discrepancy between the Li abundance in metal-poor stars (Spite plateau stars) and the predictions from standard Big Bang Nucleosynthesis. In all three cases we find that the “problems” are naturally explained by non-standard mixing in stars.  相似文献