ABSTRACT:The evaluation of the possible climate change influence on extreme precipitation is very interesting in the Mediterranean area due to the usual and characteristic high intensities of its rainfall pattern. This analysis is also very important in urban zones, especially those densely populated with complex sewer systems, generally vulnerable to torrential rainfall. In this work, a total of 114 simulated daily rainfall series, 84 for the period 2000-2099 and 30 for the control period 1951-1999, have been analysed. These series were obtained for six thermo-pluviometric stations located in the metropolitan area of Barcelona using the information provided by five general circulation models under four future climate scenarios of greenhouse gas emissions and applying statistical downscaling methods. The potential changes in the intensity-duration-frequency relationships due to climate change have been investigated. For the last third of the 21st century, under A1B, A2 and B2 climate scenarios, an increase of at least 4% has been found on the expected daily rainfall with return period longer than 20 years. Using a temporal downscaling based on scaling properties of rainfall, future hourly extreme rainfall has been estimated. For almost all the scenarios and periods considered, the increase on the expected hourly rainfall has resulted slightly higher than the corresponding daily rainfall. The greatest differences between the future hourly and daily rainfall estimated have been found in the second third of the century under scenarios A1B (8%) and A2 (9%).

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ABSTRACT:The main objective of this study is to estimate the probable maximum precipitation (PMP) in Barcelona for durations ranging from 5 min to 30 h. To this end, rain records from the Jardí gauge of the Fabra Observatory located in Barcelona (1927Barcelona ( -1992) and the urban pluviometric network supported by Clavegueram de Barcelona, S.A. (CLABSA, 1994(CLABSA, -2007 were analysed. Two different techniques were used and compared: a physical method based on the maximization of actual storms, and the Hershfield' statistical method. The PMP values obtained using the two techniques are very similar. In both cases, the expected increasing behaviour of the PMP with duration was found, with the increase especially notable for the mesoscale durations 2-9 h, and not significant from 12 h on up. This result seems to be related to the scale of the meteorological situations producing high intense rainfall amounts over our territory.

In this paper we present an automatic system able to detect the internal structure of executions of high-performance computing applications. This automatic system is able to rule out non-significant regions of executions, to detect redundancies, and, finally, to select small but significant execution regions. This automatic detection process is based on spectral analysis (wavelet transform, Fourier transform, etc.) and works detecting the most important frequencies of the application’s execution. These main frequencies are strongly related to the internal loops of the application’s source code. The automatic detection of small but significant execution regions shown in the paper reduces the load of the performance analysis process remarkably.