Tres estudios sobre el medio natural en Castilla y León

Bibliografía. - Indice

Characterisation of snowfall events in the northern Iberian Peninsula and the synoptic classification of heavy episodes (1988-2018)

Historic snowfall events in the northern Iberian Peninsula recorded between 1988 and 2018 are presented and analysed. This study makes use of data collected over a course of 31 years from 105 observation stations. These weather reports describe the temporal and spatial characteristics of five Spanish provinces facing the Cantabrian Sea. The average number of snow events observed per year (as recorded by all 105 stations) was 133, where a maximum of 421 snow events was recorded in 2010 and a minimum of 24 events were recorded in 2002. In addition, the monthly distribution of snow events per day had a maximum of 630 events, (February), with a mean monthly value of 170 snow events. Other features like the distribution of snow events depending on the altitude of each province studied and the corresponding spatial patterns are also shown. Furthermore, the circulation patterns responsible for heavy snowfall in the region were also examined. To carry out this study, we considered the daily patterns at 1200 UTC of the geopotential height at 500 and 850 hPa pressure levels and sea‐level pressure and temperature at 500 and 850 hPa respectively. The synoptic situations were classified based on a principal component analysis coupled with a K‐means clustering, and four groups associated with heavy snowfall events were subsequently identified. The analysis of the daily synoptic patterns showed that a trough was present over the Iberian Peninsula, or close by, and a low appeared over the Mediterranean Sea or Central Europe. The low‐level flow was from the north (N) or northeast (NE) in ~ 85% of the cases and the temperature at 850 hPa pressure level was lower than ‐3°C in ~ 70% of the cases

Observed impact of land uses and soil types on cloud-to-ground lightning in Castilla-Leon (Spain)

The impact of land use on lightning activity has mainly been studied for urban areas; however the number of authors addressing the impact of vegetation on lightning is fairly limited. The relationship of different types of land use and soil (thirteen categories of land use and fourteen major soil types were considered) on cloud-to-ground lightning activity was studied in the Spanish region of Castilla-León from 2000 to 2010. To do this, urban, mining, and industrial areas were found to be associated with enhanced CG-lightning activity. With respect to natural land uses, forest and shrubland were the categories where CG-lightning was seen to be increased. By contrast, non-agricultural vegetated areas and pastures displayed the lowest CG-lightning activity. When the major soil types are considered, rendzinas, podzols, and phaeozems were found to be associated with a slight increase in CG-lightning activity and gleysols and solonchaks seem to decrease it. Assuming there are a plethora of factors which can indirectly affect the charging electromicrophysics and cloud dynamics, the authors provide evidence that soil type shows a significant correlation on CG-lightning flash density and weather characteristics are affected by land uses. It is suggested that the influence of vegetation and soil on surface moisture is one of the main effects contributing to explain the impact of land cover on CG-lightning

Distribución de la precipitación en la Cuenca del Duero

[ES] Se obtiene una distribución de los valores medios anuales de la precipitación en la Cuenca del Duero, basándose en cuatro parámetros geográficos y topográficos (altitud, laplaciana de la altitud y distancia al mar en las direcciones Noroeste y Norte) para su cálculo.[EN] In order to calculare it we must obtain -a distribution of the average annual rainfall in the Duero Basin, taking into consideration four geographical and topographical parameters to calculate it: altitude, laplacian of the altitude and distance to the sea in the Northwest and North directions

Introducción al estudio de la transparencia atmosférica en Salamanca

[ES]Partiendo de obsérvaciones de radiación solar global diaria (G) recibida en Salamanca durante el período 1977-85 sobre una superficie horizontal, y calculando la radiación solar máxima recibida en el límite de la atmósfera (H0), se ha deducido un índice de claridad diario (K=G/H0 ), que indica el grado de transparencia atmosférica.[EN]Using nine years (1977-85) continuous records of daily global solar radiation (G) at Salamanca, and theoretical values of extraterrestrial solar radiation (H0) on a horizontal plane, the ratio of global to extraterrestrial solar radiation is presented (G/H0=K: daily clearness index)

Nuevas consideraciones y mejoras en la aplicación de la distribución de precipitación en la cuenca del Río Duero

[EN]In this study we present a new contribution to take into account for a correct explanation of the rainfall observed in the mentioned area. Our contribution consists basically in considering three new aspect negleted in previous researchs: firstly, we confirm and quantify the importance of second-order terms in the proposed geo-climatic factors; secondly, we include among these a new parameter which explains a meteorological aspect not considered up to now; finally we make "the normalitation" or correction 10 one of the factors already defined.[ES]En este trabajo presentamos las nuevas aportaciones a tener en cuenta para una correcta explicación de la precipitación observada en la zona estudiada. Básicamente consisten en tener en cuenta tres aspectos ignorados en trabajos anteriores: conformar y cuantificar la importancia de los térmicos de segundo orden en los factores geo-climáticos propuestos; introducir en los mismos un nuevo parámetro que viene a explicar cierto aspecto meteorológico no tenido en cuenta, y por último efectuar la normalización o corrección en uno de los factores ya definidos

Intense precipitation events in the Central Range of the Iberian Peninsula

Intense orographic precipitation associated with the Central Range was analysed using data of maximum accumulated precipitation in 24 h, occurring between 1958 and 2010. The 18 selected episodes were associated with a southwesterly tropospheric flow, a low-level jet, and high moisture flux at low levels. The observed moisture flux was higher than 100 (m g(s kg)−1) and the dry and wet Froude numbers were greater than 1. The selected area to study this synoptic situation was Gredos, broad and high range, which is located in the eastern part of the Central Range and generates a leeward “orographic shadow”. The effect of the Central Range on the spatial distribution of precipitation on the Iberian Peninsula plateau results in a sharp increase in precipitation in the south of the Central Range, followed by a decrease to the north of this range

Perfiles verticales de energías estáticas en el desarrollo convectivo sobre las Islas Canarias: un episodio de estudio 15 al 20 de febrero de 1989

En este trabajo se analiza una aplicación práctica de un modelo de predicción de desarrollo convectivo. El episodio estudiado tiene lugar en el período del 16 al 20 de febrero de 1989 sobre las Islas Canarias

Modelo estocástico para generar variables atmosféricas diarias. Aplicación a Salamanca y Oporto

Ponencia presentada en: XXXI Jornadas Científicas de la AME y el XI Encuentro Hispano Luso de Meteorología celebrado en Sevilla, del 1 al 3 de marzo de 2010