Papers by Leonardo S Nania
. The south-central interior of Andalusia experiences intricate precipitation patterns as a resul... more . The south-central interior of Andalusia experiences intricate precipitation patterns as a result of its semi-arid Mediterranean climate and the impact of Saharan dust and human-made pollutants. The primary aim of this study is to monitor the inter-relations between various factors, such as aerosols, clouds, and meteorological variables, and precipitation systems in Granada using ground-based remote sensing and in situ instruments including microwave radiometer, ceilometer, cloud radar, nephelometer, and weather station. The objective is to identify potential properties of precipitation in the region and in that way improve precipitation forecasting. Over an 11-year period, we detected rain events using a physical retrieval method that employed microwave radiometer measurements. A composite analysis was applied to them to construct a climatology of the temporal evolution of precipitation. It was found that convective rain is the dominant precipitation type in Granada, accounting for 68 % of the rain events. The height of the cloud base is mainly distributed at an altitude of 2 to 7 km. Integrated water vapor (IWV) and integrated cloud liquid water (ILW) increase rapidly before the onset of rain. Aerosol scattering at surface level and hence the aerosol concentration is reduced during rain, and the predominant mean size distribution of aerosol particles before, during, and after rain is almost the same. A meteorological environment favorable for virga formation is observed in Granada. The surface weather station detected rainfall later than the microwave radiometer, indicating virga according to ceilometer and cloud radar data. We used rain-day events identified by weather station data to determine precipitation intensity classes and found that light rain is the main precipitation intensity class in Granada, accounting for 72 % of the rain-day events. This can be a result of the high tropospheric temperature induced by the Andalusian climate and the reduction of cloud droplet size by the high availability of aerosol particles in the urban atmosphere. This study provides evidence that aerosols, clouds, and meteorological variables have a combined impact on precipitation which can be considered for water resource management and improving rain forecasting accuracy.
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<p class="Standarduser"><span lang="EN-US">Rainfa... more <p class="Standarduser"><span lang="EN-US">Rainfall prediction is one of the most challenging and uncertain tasks in weather forecasting, which has a significant impact on human society. Detection of heavy rainfall trends may be masked or amplified by natural variability, and numerical weather prediction (NWP) models have difficulty to predict them accurately. Therefore, understanding of rainfall effects with the evolution of atmospheric parameters and seeking atmospheric precursors of rainfall for nowcasting or prediction become an urgent need.</span></p> <p class="Standarduser"><span lang="EN-US">To date, most related studies have analyzed only a limited number of rain events or lacked long-term observations. This is likely to have a weak robustness. A multi-instrument and multi-parameter atmospheric monitoring system to detect precipitation precursors can improve the existing nowcasting system. </span><span lang="EN-US">AGORA (Andalusian Global ObseRvatory of the Atmosphere) is an ACTRIS facility located in the southeast of the Iberian Peninsula which offers unique infrastructure for the study of aerosol, clouds and precipitation. AGORA consists of two stations, an urban station located in the city of Granada (680 m asl) and a high-mountain station located in the National Park of Sierra Nevada (2580 m asl), separated by a horizontal distance of 20 km only. This infrastructure comprises state-of-the-art instrumentation covering active and passive remote sensing and in-situ techniques, including lidars, cloud radars, microwave radiometer, and weather stations. These instruments can obtain multiple atmospheric parameters (atmospheric water, aerosol, temperature, wind, etc.), including their vertical profiles.</span></p> <p class="Standarduser"><span lang="EN-US">In this study, we investigate the potential of different atmospheric parameters from ground-based microwave radiometer, ceilometer, nephelometer, absorption photometer and weather stations for the nowcasting of rainfall. We use 694 rain events identified by microwave radiometer in the southeast of Iberian Peninsula to identify conditions favorable to trigger rainfall over 10 years, and to analyze how they are related to observed changes in water vapor and aerosol load and properties. The composite analysis is carried out in a long time interval of 8 hours before and 16 hours after rain, with the onset of rain serving as the time marker for this method. The aim of our study is to show the typical behavior of rainfall, to reveal the interaction of rainfall with atmospheric parameters, and to explore the precursors of rainfall.</span></p>
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Journal of Hydraulic Engineering, 2013
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Proceedings of the 39th IAHR World Congress
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Water, 2022
In the present study, the hydraulic operation of flow through transverse bottom racks screens wit... more In the present study, the hydraulic operation of flow through transverse bottom racks screens with conventional triangular wedge wire and alternative circular section wire is experimentally and numerically analyzed. A laboratory prototype is built for experimentation with clean water and sediment. The numerical experiment is developed with the Ansys Fluent software, and a 2D CFD parametric study is designed to evaluate the influence on the captured flow of geometric variables, such as the screen incline, position of the screen along the channel (top, middle, bottom), and shape, wire width, or slot width. The physical model results make it possible to determine the efficiency of the screens in terms of collection capacity and sediment removal. In contrast, numerical experimentation determines the influence of geometric variables on the collection flow. The flows captured by each screen slot are determined numerically. The trends of the total flows captured are determined, and the per...
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Journal of Hydrologic Engineering, 2015
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institucional.us.es
modelos de circulación en ríos y embalses. Juan Francisco Navarro Paradas*, Leonardo Nanía Escoba... more modelos de circulación en ríos y embalses. Juan Francisco Navarro Paradas*, Leonardo Nanía Escobar*, Antonio Moñino Ferrando*, Sergio Nieto Liñan*, Joaquín Ortega Casanova**. *Grupo de Ríos y Embalses, Centro Andaluz de Medio Ambiente, Universidad de Granada,. ...
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En los últimos años, el continuo crecimiento de las áreas urbanas ha incrementado los problemas o... more En los últimos años, el continuo crecimiento de las áreas urbanas ha incrementado los problemas ocasionados por inundaciones, especialmente en las grandes ciudades. Estos problemas aparecen debido a: la disminución del área permeable; el aumento tanto del ...
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filo.uba.ar
Page 1. MODELOS DE GENERACIÓN Y CIRCULACIÓN DE ESCORRENTIA Leonardo Nanía Escobar*, María José Po... more Page 1. MODELOS DE GENERACIÓN Y CIRCULACIÓN DE ESCORRENTIA Leonardo Nanía Escobar*, María José Polo Gómez**, Adolfo Peña Acevedo** *Grupo de Ríos y Embalses, CEAMA, Universidad de Granada, Avda. del Mediterráneo, s/n, 18006, Granada, Tel. ...
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Ingenieria Hidraulica En Mexico, 2006
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The authors of this paper provide a valuable discussion on the potential dangers of conduit skele... more The authors of this paper provide a valuable discussion on the potential dangers of conduit skeletonization and subcatchment aggregation. For assessing these potential dangers, a "base model " (includes all sewers, nodes, inlets and gutters) and simplified models (successive removal of elements) of two catchments were used. The discussers congratulate the authors for their work on this relevant issue and for presenting their results in a clear and well organized way. The discussers however would like to raise some questions and comments regarding the results and their interpretation as presented in the paper. The paper states “in using simplified models there is a danger that the user may not correctly predict the magnitude, timing, and shape of the outfall hydrograph”. The latter
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filo.uba.ar
Page 1. MODELOS DE GENERACIÓN Y CIRCULACIÓN DE ESCORRENTIA Leonardo Nanía Escobar*, María José Po... more Page 1. MODELOS DE GENERACIÓN Y CIRCULACIÓN DE ESCORRENTIA Leonardo Nanía Escobar*, María José Polo Gómez**, Adolfo Peña Acevedo** *Grupo de Ríos y Embalses, CEAMA, Universidad de Granada, Avda. del Mediterráneo, s/n, 18006, Granada, Tel. ...
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institucional.us.es
modelos de circulación en ríos y embalses. Juan Francisco Navarro Paradas*, Leonardo Nanía Escoba... more modelos de circulación en ríos y embalses. Juan Francisco Navarro Paradas*, Leonardo Nanía Escobar*, Antonio Moñino Ferrando*, Sergio Nieto Liñan*, Joaquín Ortega Casanova**. *Grupo de Ríos y Embalses, Centro Andaluz de Medio Ambiente, Universidad de Granada,. ...
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38th IAHR World Congress - "Water: Connecting the World"
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World Environmental and Water Resources Congress 2009, 2009
Abstract This work is part of a long term project which aims to simulate (1) the hydrology,(2) st... more Abstract This work is part of a long term project which aims to simulate (1) the hydrology,(2) street flows,(3) flow interception at inlets and (4) storm-sewer flows in urban areas. The present work describes the application of the model using only the first two modules. The hydrologic model (first module) transforms rainfall to runoff using the kinematic wave approximation and simulating the infiltration process with the Green-Ampt method. The street model (second module) is based on a finite volume-shock capturing scheme that ...
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Journal of Hydrologic Engineering, 2015
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Abstract The authors of this paper provide a valuable discussion on the potential dangers of cond... more Abstract The authors of this paper provide a valuable discussion on the potential dangers of conduit skeletonization and subcatchment aggregation. For assessing these potential dangers, a" base model"(includes all sewers, nodes, inlets and gutters) and simplified models (successive removal of elements) of two catchments were used. The discussers congratulate the authors for their work on this relevant issue and for presenting their results in a clear and well organized way.
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Journal of Hydraulic Research
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Journal of Hydraulic Research
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Papers by Leonardo S Nania