Spatial and temporal patterns of the stability and humidity terms in the Haines index to improve the estimate of forest fire risk in the Valencia region of Spain

Ponencia presentada en: IX Congreso de la Asociación Española de Climatología celebrado en Almería entre el 28 y el 30 de octubre de 2014.[EN]The assessment of risk index in the propagation and evolution of a hypothetical forest fire is commonly based on stability and moisture content at different atmospheric levels. The Haines Index combines these terms to determine the environmental potential for wildfire growth. In this study the environmental stability and humidity associated with the lower atmospheric layers in the Western Mediterranean Basin are investigated by analysing Haines Index calculations over a 29 year period.[ES]La evaluación del índice de riesgo en la propagación y evolución de un hipotético incendio forestal está basada habitualmente en la estabilidad y el contenido de humedad en los diferentes niveles atmosféricos. El Índice de Haines combina estos términos para determinar el potencial ambiental en el desarrollo de un incendio forestal. En este estudio la estabilidad ambiental y la humedad asociada a las capas atmosféricas más bajas de la cuenca del Mediterráneo occidental se investigan mediante el análisis del cálculo del Índice de Haines durante un período de 29 años.We thank NCEP/NCAR for supplying the data necessary for this study. This study was supported by the Spanish Ministry of Innovation and Science (projects CGL2010-16364, CGL2011-30433-C02 and GRACCIE Consolider-Ingeio 2010; and Dr. Niclòs "Ramón y Cajal"Research Contract) and Generalitat Valenciana (Prometeo/2009/006 FEEDBACKS project). The Instituto Universitario CEAM-UMH is partly supported by the Generalitat

Tendencia de la temperatura en los meses de julio y agosto en la Comunidad Valenciana en las últimas décadas: cambios en la frecuencia de días calurosos

Ponencia presentada en: IV Congreso de la Asociación Española de Climatología "El Clima entre el Mar y la Montaña", celebrado en Santander del 2 al 5 de noviembre de 2004.[ES]Dentro de la temática del cambio climático, la temperatura en los meses estivales tiene un especial interés por las consecuencias económicas, sociales y ambientales que se derivarían de un ascenso, como se ha visto en el extraordinario verano del 2003. Diversos estudios recientes han puesto de manifiesto la tendencia al aumento de la calidez estival. Sin embargo, para el caso concreto de la Comunidad Valenciana en el presente estudio se dilucida que, dentro de una tendencia de base al ascenso térmico, la mayor responsabilidad del cambio recae en una mayor frecuencia de días con características térmicas tropicales de calor persistente, que no por una tendencia a batir récords al alza de temperaturas máximas absolutas.[EN]Within the subject of the climatic change, summer temperatures are of special interest because of the economic, social and environmental consequences that can be derived from their hypothetical increase. A number of recent studies have shown a trend to the increase of summer heating. In this work we analyse the temperature of the hottest summer months since 1958 to nowadays, with the objective to characterise the evolution of temperature and to find if there is a trend towards a higher frequency of hottest days. The first results show that there is a higher frequency of days with tropical characteristics and persistent heat; on the contrary, we did not find a trend to exceed records of absolute maximum temperatures.Este trabajo ha sido realizado con el apoyo del Ministerio de Ciencia y Tecnología, contrato número REN2001-1086/HID

Improving RAMS and WRF mesoscale forecasts over two distinct vegetation covers using an apprpiate thermal roughness length parameterization

Land Surface Models (LSM) have shown some difficulties to properly simulate day-time 2-m air and surface skin temperatures. This kind of models are coupled to atmospheric models in mesoscale modelling, such as the Regional Atmospheric Modeling System (RAMS) and the Weather Research and Forecasting (WRF) Model. This model coupling is used within Numerical Weather Prediction Systems (NWP) in order to forecast key physical processes for agricultural meteorology and forestry as well as in ecological modelling. The current study first evaluates the surface energy fluxes and temperatures simulated by these two state-of-the-art NWP models over two distinct vegetated covers, one corresponding to a poor and sparsely vegetated area and the other one corresponding to the tall and well-vegetated area of a forest. On the other hand, the importance of parameterizing the thermal roughness length within the LSM coupled to the corresponding atmospheric model is also evaluated. The LEAF-3 LSM is used within the RAMS modelling environment while the Noah-MP LSM is applied within WRF. Results indicate that the original version of the models underestimates the temperature during the day, more remarkably in the forested area, whereas modifications in the thermal roughness length successfully simulates the temperature and sensible heat flux forecasts over this area. This study highlights the key role of the surface exchange processes when coupling land and atmosphere models. In this regard, incorporating an extra resistance in the surface-layer parameterization through the thermal roughness length is essential to simulate well both temperatures and sensible heat fluxes, which becomes more relevant over tall and well-vegetated areas, such as a forest. This extra resistance for heat exchange prevents effective molecular diffusion in the layer between the momentum roughness length and the thermal roughness length. Additionally, an appropriate description of the canopy height permits to apply an improved surface-layer formulation over different land and vegetation covers

Spatio-temporal variability of fog-water collection in the eastern Iberian Peninsula: 2003-2012

Among the different inputs involved in the hydrological system, fog water measured by man-made passive devices is one of the most unknown components, although it could be an additional water resource for specific environmental applications (forest restoration, forest firefighting, etc.). Focusing on the Mediterranean Iberian Peninsula, the aim of this work is to quantify fog-water collected by a 24-fog-stations network spread across three latitudinal sectors with different locations (coastal, pre-littoral and inland), and to determine the most productive sites. Measurements from the network show that distance-to-sea, latitude or elevation differences between stations are factors affecting fog-water collection potential. The network, based on passive cylindrical omnidirectional fog-water collectors, was active during the period 2003-2012. In addition to fog collection, other environmental variables such as rainfall, wind speed and wind direction, air temperature and relative humidity were measured. These ancillary data were used in a specific data reduction technique to eliminate the simultaneous rainwater component from the fog water measurements, and in the retrieval of the optimum mean wind directions to harvest fog-water efficiently. It was concluded that (i) positive differences in elevation allow greater collection rates, even under 100m differences; (ii) optimum harvesting wind directions for inland locations are in line with the orientation of the existent valley coupled with the shortest path to the coastline, their collected fog-water volumes being generally smaller than those near the coast; (iii) fog-water collection at coastal locations present more dispersed optimal wind directions, ranging from north to the direction of the most immediate coastline; and (iv) there is a practically null dependence of the optimum mean wind direction on seasonality, but a strong dependence of fog-water captured volumes, however

Comparative assessment of RAMS and WRF short-term forecasts over Eastern Iberian Peninsula using various in-situ observations, remote sensing products and uncoupled land surface model datasets

The Regional Atmospheric Modeling System (RAMS) and the Weather Research and Forecasting (WRF) mesoscale models are being used for weather and air quality studies as well as forecasting tools in Numerical Weather Prediction (NWP) systems. In the current study, we perform a comparative assessment of these models under distinct typical atmospheric conditions, classified according to the dominant wind flow and cloudiness, over Eastern Iberian Peninsula. This study is focused on the model representation of key physical processes in terms of meteorology and surface variables during a 7-days period in summer 2011. The hourly outputs produced by these two models are compared not only with observed standard surface variables, measured at different permanent weather stations located over the region of study, but also with different surface remote sensing products and uncoupled Land Surface Models (LSM) datasets. Confronting RAMS and WRF, the current study highlights relevant differences over areas near the coast when mesoscale circulations or Eastern synoptic advections are developed over the region of study. A higher moisture content is observed under these atmospheric conditions, due to the moisture transport by the sea breeze inland. In this regard, it has been found that the Eastern wind field simulated by WRF reaches inland areas and comprises a larger sea breeze extension than RAMS. This sea breeze development impacts meteorology and surface variables in locations not too close to the coast, but still affected by land-sea winds. Additionally, WRF remains more windy and moister than RAMS at night-time, while alike results are found under Western synoptic advections. The results obtained in the current paper show differences under distinct dominant atmospheric conditions, which outline further research in this field in order to achieve more general conclusions

RAMS-forecasts comparison of typical summer atmospheric conditions over the Western Mediterranean coast

The Regional Atmospheric Modeling System (RAMS) has been used in order to perform a high-resolution numerical simulation of two meteorological events related to the most common atmospheric environments during the summer over the Western Mediterranean coast: mesoscale circulations and western synoptic advections. In this regard, we take advantage of the operational RAMS configuration running within the real-time forecasting system environment already implemented over this Mediterranean area, precisely in the Valencia Region and nearby areas. The attention of this paper is especially focused on identifying the main features of both events and the ability of the model in resolving the associated characteristics as well as in performing a comprehensive evaluation of the model by means of diverse meteorological observations available within the selected periods over the area of study. Additionally, as this paper is centred in RAMS-based forecasts, two simulations are operated applying the most two recent versions of the RAMS model implemented in the above-mentioned system: RAMS 4.4 and RAMS 6.0. Therefore, a comparison among both versions of the model has been performed as well. Finally, it is our intention to contrast the RAMS forecasts for two completely different atmospheric conditions common with the area of study in the summer. A main difference between the simulation of both meteorological situations has been found in the humidity. In this sense, whilst the model underestimates this magnitude considering the mesoscale event, especially at night time, the model reproduces the daily humidity properly under the western synoptic advection

Future Projection of precipitation changes in the Júcar and Segura River Basins (Iberian Peninsula) by CMIP5 GCMs Local Downscaling

The basins of the Júcar and Segura rivers, on the Mediterranean coast of the Iberian Peninsula, present a special water problem and are of particular interest regarding climate change. These basins are very vulnerable to a possible scenario of decreasing water resources. Recent studies on historic rainfall since 1955 have indicated an ongoing loss of precipitation in their headwaters, especially in the case of the Júcar river. The aim of the present study is to perform climate projections for the precipitation variable for several future periods (2021-2040, 2051-2070, 2081-2100) and emission scenarios (RCPs 4.5, 8.5) within the Júcar and Segura River Basin authorities. For this purpose, a set of CMIP5 global models have been used, as well as the CDRD-HR-EIP-1955-2016 database, as a source of local observed information. This database comprises nearly 900 precipitation series in both basins and has been used in recent studies to determine historic trends of change in these basins. A statistical downscaling of the global models for all available observed series has been applied using the LARS-WG method. The results, although variable according to the CMIP5 model used, show the continuation of the patterns of precipitation change in the future, as already observed in the historical series. The results also predict a clear reduction in precipitation in the long term. However, torrential rainfall tends to increase in the coastal areas in relation to that observed in the short-term predictions. These results, due to their high spatial resolution, are of great interest for their use in small-scale hydrological and spatial planning (regional and local), which is one of the current challenges of climate modeling

Análisis de tendencia de la precipitación por frentes atlánticos en la Comunidad Valenciana (1959-2004)

Ponencia presentada en: V Congreso Internacional de la Asociación Española de Climatología celebrado en Zaragoza del 18 al 21 de septiembre de 2006.[ES]El objetivo de este trabajo es el análisis territorializado de la tendencia de la precipitación en la Comunidad Valenciana para las situaciones de tipo frontal. Los resultados obtenidos para el periodo 1959-2004 indican una clara tendencia general de la precipitación al descenso en los totales anuales, y sobre todo diarios, con valores estadísticamente más significativos según el test de Mann-Kendall en el interior de la Comunidad. Los mayores descensos se recogen en el primer semestre y el interior Norte que, por otro lado, es la zona donde este tipo de precipitaciones tiene mayor peso y repercusión.[EN]The results obtained for the 1954-2004 period indicate a clear generalised trend towards decreased precipitation both in the annual totals and, especially, in the daily totals, with statistically more significant values (according to the Mann-Kendall test) in the interior of the region. The largest decreases are noted in the first half of the year and in the northern interior, which is also the area where this precipitation type has traditionally been more important

Análisis de un evento extraordinario de recolección de agua de niebla en la vertiente mediterránea de la Península Ibérica (marzo 2011)

Ponencia presentada en: XII Congreso de la Asociación Española de Climatología celebrado en Santiago de Compostela entre el 19 y el 21 de octubre de 2022.[ES]En la cuenca mediterránea de la Península Ibérica el recurso agua es un bien escaso. En los últimos años, periodos prolongados de sequía han provocado restricciones en el uso del agua que incluso han llegado a afectar al consumo humano. En el contexto actual, donde el cambio climático está provocando que estos periodos prolongados sin precipitación en el área mediterránea puedan darse con mayor frecuencia e intensidad, es fundamental el orientar la investigación hacia la búsqueda de fuentes alternativas de agua que ayuden a mitigar esta problemática. Se ha analizado la captación de agua de niebla en la fachada mediterránea de la Península Ibérica a partir de una red de 24 colectores que se extiende desde Girona (Cataluña) hasta Almería (Andalucía). Se han obtenido valores de recolección que, en la época estival, han llegado a superar a los de la precipitación, revelándose, por tanto, como una fuente alternativa de agua de gran interés especialmente en aplicaciones medioambientales. El trabajo que aquí se presenta analiza la génesis de un episodio de recolección de agua de niebla donde las tasas de captación fueron extraordinariamente elevadas en algunos de los emplazamientos estudiados. Dicho episodio tuvo lugar entre los días 22 y 25 de marzo de 2011, llegándose a recolectar en algunos casos más de 450 l/m2 en las 77 horas en las que hubo captura ininterrumpida de agua. El estudio muestra diferencias notables en los volúmenes recolectados en función de la ubicación de los colectores, habiéndose obtenido las mayores capturas en la zona centro y sur del área de estudio.[EN]In the Mediterranean basin of the Iberian Peninsula, water scarcity is present. In recent years, prolonged periods of drought have caused restrictions in water use that have even affected human consumption. In this area, climate change is causing more frequent periods with no precipitation, but also with greater intensity (heavy rains), so it is vital to investigate alternative sources of water. In the Mediterranean coast of the Iberian Peninsula, fog-water collection has been analyzed from a network of 24 collectors extending from Girona (Catalonia) to Almeria (Andalusia). Collection values have been obtained which, in the summer season, have exceeded those of precipitation, thus revealing itself as an alternative source of water of great interest, especially in environmental applications. This work analyzes the origin of a fog-water collection episode where collection rates were extraordinarily high in some of the studied locations. This episode took place between 22 and 25 March 2011, and, in some cases, volumes above 450 l/m2 were collected in the 77 hours in which there was non-stop water capture. The study shows important differences in the collected volumes depending on the collectors location, with the highest water volumes being obtained in the central and southern part of the study area.Este trabajo ha sido cofinanciado por el proyecto PID2020-118797RB-I00 financiado por MCIN/ AEI /10.13039/501100011033 (Ministerio de Ciencia e Innovación), y por la Conselleria d’Innovació, Universitats, Ciència i Societat Digital de la Generalitat Valenciana a través del proyecto de investigación PROMETEO/2021/016

Cambios a fina escala de la aridez en la Comunidad Valenciana entre 1948 y 2011

Ponencia presentada en: X Congreso de la Asociación Española de Climatología celebrado en Alicante entre el 5 y el 8 de octubre de 2016.[ES]Recientes avances en downscaling estadístico e interpolación espacial de temperaturas han resultado en la disponibilidad del dataset SDSITVC (Statistical Downscaling and Spatial Interpolation of Temperatures for the Valencian Community), con una resolución espacial de 90 m y periodo completo de 1948-2011, para la Comunidad Valenciana y áreas limítrofes. El presente trabajo busca relacionar dicha interpolación de temperaturas con otra de precipitaciones que, al igual que el SDSITVC, sea apta para el análisis de tendencias entre 1948 y 2011.[EN]Recent advances in statistical downscaling and spatial interpolation of temperatures have resulted in the availability of the SDSITVC dataset (Statistical Downscaling and Spatial Interpolation of Temperatures for the Valencian Community). This complies a spatial resolution of 90 m and full 1948-2011 period, for the Valencian Community and surrounding areas. This paper seeks to relate this temperature interpolation with other for precipitation in the same way suitable for the analysis of trends between 1948 and 2011.Este trabajo se ha realizado gracias al programa PROMETEOII (2014/086) de la Comunidad Valenciana, y el proyecto CGL2015- 64268-R (MINECO/FEDER, UE) del Ministerio de Economía y Competitividad y el FEDER