15 research outputs found

    La llicenciatura en Física: Perfil de la professió. Estudi d’inserció professional

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    Les oportunitats professionals dels llicenciats i llicenciades en FĂ­sica han evolucionat molt en el passat immediat, i tambĂ© s’ha ampliat els tipus de sectors laborals que enrolen fĂ­sics. Fa just trenta anys, la major part dels titulats era absorbida pel sector de l’ensenyament secundari i superior. Una minoria aconseguia fer carrera de recerca, principalment en centres acadĂšmics. En l’actualitat el panorama ha canviat força ja que, com revelen algunes enquestes a graduats recents de mitjan els anys noranta, la sortida professional de l’ensenyament nomĂ©s representava un 50 % del total

    Quality control process of the daily rainfall series available in Catalonia from 1855 to the present

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    The quality control of weather data is a necessity and a responsibility of meteorological services that store, distribute, and use these data. In the present work, a newly designed quality control procedure for daily rainfall data is presented after it has been adjusted and tested with more than 10^7 data from 1726 daily rainfall measurement sites in Catalonia. It is applicable to data from different origins (e.g., automatic weather stations or manual historical measurements). The procedure is focused on relative comparison of daily data with reference stations that are automatically selected after an initial estimation of their quality and a proximity study regarding location and correlation. The presented procedure has been verified taking advantage of an available network in the study area that has been routinely quality controlled by technicians of the Meteorological Service of Catalonia. The newly designed quality control procedure for daily precipitation yields good results, especially for extreme values: type I error under 10% is found for values up to 150 mm (error decreasing for lower values) and type II error is under 16% when reported values are twice a measure of 50 mm or more (error decreasing for more extreme values). After the application of the quality control procedure, a selection of series with the minimum desired quality is achieved.Peer Reviewe

    La llicenciatura en Física: Perfil de la professió. Estudi d’inserció professional

    No full text
    Les oportunitats professionals dels llicenciats i llicenciades en FĂ­sica han evolucionat molt en el passat immediat, i tambĂ© s’ha ampliat els tipus de sectors laborals que enrolen fĂ­sics. Fa just trenta anys, la major part dels titulats era absorbida pel sector de l’ensenyament secundari i superior. Una minoria aconseguia fer carrera de recerca, principalment en centres acadĂšmics. En l’actualitat el panorama ha canviat força ja que, com revelen algunes enquestes a graduats recents de mitjan els anys noranta, la sortida professional de l’ensenyament nomĂ©s representava un 50 % del total

    Analysis of the precipitation and cloudiness associated with COLs occurrence in the Iberian Peninsula

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    The Iberian Peninsula is one of the regions in the world with higher occurrence of cut-off low systems (COL). The aim of this paper is to analyse the weather events (rainfall and cloudiness layer) associated to COLs in the Iberian Peninsula with tools not previously used: (a) the use of the new multidecadal COLs database developed by Nieto et al (2005) that permit us to study a 41 years period (1958-1998), (b) the checking of the expected weather events (rainfall and cloudiness layer) associated with COLs in a conceptual model (Winkler et al, 2005) and (c) the extensive use of radiosoundings to analyse convective instability in areas inside and close to the COL. Two points of view are used to make the analysis: (1) a source oriented method, when a particular COL is followed and its associated precipitation and cloudiness is analysed over four quadrants in which Iberia was divided and (2) a receptor oriented method, when the precipitation associated to COLs is analysed in given areas, defined by patterns of precipitation. Results reveal that the precipitation and cloudiness patterns associated to COLs in the conceptual model reproduce quite well the main characteristics found over the Iberian Peninsula. The generalized idea that most of the COLs produce intense convective rainfall is show to be misleading. Convective phenomena are important usually when the centre of the COL is located on the Mediterranean region. Most of the rainfall associated with COLs comes from the baroclinic shield; specially in cases located over the west half of the Iberian Peninsula. It is shown that nearly 30% of COLs do not induce any rainfall; most of them located in the southern half of the Peninsula, and mainly during autumn. Only 30% of COLs produce generalized rainfall over the whole analysed territory, being most of them (about 90%) located over the western half of the Iberian Peninsula

    Cloud cover analysis associated to cut-off low-pressure systems over Europe using Meteosat Imagery

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    This paper reports a cloud cover analysis of cut-off low pressure systems (COL) using a pattern recognition method applied to IR and VIS bispectral histograms. 35 COL occurrences were studied over five years (1994-1998). Five cloud types were identified in COLs, of which high clouds (HCC) and deep convective clouds (DCC) were found to be the most relevant to characterize COL systems, though not the most numerous. Cloud cover in a COL is highly dependent on its stage of development, but a higher percentage of cloud cover is always present in the frontal zone, attributable due to higher amounts of high and deep convective clouds. These general characteristics are most marked during the first stage (when the amplitude of the geopotencial wave increases) and second stage (characterized by the development of a cold upper level low), closed cyclonic circulation minimizing differences between rearward and frontal zones during the third stage. The probability of heavy rains during this stage decreases considerably. The centres of mass of high and deep convective clouds move towards the COL-axis centre during COL evolution

    Interannual variability of cut-off low systems over the European sector: The role of blocking and the Northern Hemisphere circulation modes

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    An earlier developed multidecadal database of Northern Hemisphere cut-off low systems (COLs), covering a 41 years period (from 1958 to 1998) is used to study COLs interannual variability in the European sector (25 degrees-47.5 degrees N, 50 degrees W-40 degrees E) and the major factors controlling it. The study focus on the influence on COLs interannual variability, of larger scale phenomena such as blocking events and other main circulation modes defined over the Euro-Atlantic region. It is shown that there is a very large interannual variability in the COLs occurrence at the annual and seasonal scales, although without significant trends. The influence of larger scale phenomena is seasonal dependent, with the positive phase of the NAO favoring autumn COL development, while winter COL occurrence is mostly related to blocking events. During summer, the season when more COLs occur, no significant influences were found
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