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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 107 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. [ABSTRACT FROM AUTHOR]

Heavy rainfall episodes are relatively common in the conurbation of Barcelona and neighbouring cities (NE Spain), usually due to storms generated by convective phenomena in summer and eastern and south-eastern advections in autumn. Prevention of local flood episodes and right design of urban drainage have to take into account the rainfall intensity spread instead of a simple evaluation of daily rainfall amounts. The database comes from 5-min rain amounts recorded by tipping buckets in the Barcelona urban network along the years 1994–2009. From these data, extreme 5-min rain amounts are selected applying the peaks-over-threshold method for thresholds derived from both 95% percentile and the mean excess plot. The return period curves are derived from their statistical distribution for every gauge, describing with detail expected extreme 5-min rain amounts across the urban network. These curves are compared with those derived from annual extreme time series. In this way, areas in Barcelona submitted to different levels of flood risk from the point of view of rainfall intensity are detected. Additionally, global time trends on extreme 5-min rain amounts are quantified for the whole network and found as not statistically significant. [ABSTRACT FROM AUTHOR]

An analysis of the normalised rainfall intensity curves in Barcelona (NE Spain) has been undertaken from 41 selected rain rate episodes recorded by an urban network of tipping buckets applying a 5-min integration time along the years 1994-2009. These curves, based on cumulative amount and time distributions, are modelled by a power law, this fact suggesting fractal behaviour. Four parameters characterise these curves. One of them is the exponent of the power law. Another one quantifies the intermittency of the rainfall along the episode. The other two are the coordinates of cumulative amount and time distribution from which the power law fits well the normalised curve. The total rainfall amount of the episode, its length and the coefficient of variation of the 5-min amounts are also considered as complementary parameters. Taking advantage of these seven parameters, patterns of rainfall intensity are determined for every episode. These patterns, together with the statistical distribution of 5-min amounts, maximum intensity and rainfall intermittence, should increase the knowledge on the urban rainfall regime with the aim of improving drainage design. In addition to present results, flood prevention should be complemented with extreme value analyses and quantification of return periods. [ABSTRACT FROM AUTHOR]

The fractal behavior of extreme rainfall intensities registered between 1940 and 2012 by the Retiro Observatory of Madrid (Spain) has been examined, and a simple scaling regime ranging from 25 min to 3 days of duration has been identified. Thus, an intensity-duration-frequency (IDF) master equation of the location has been constructed in terms of the simple scaling formulation. The scaling behavior of probable maximum precipitation (PMP) for durations between 5 min and 24 h has also been verified. For the statistical estimation of the PMP, an envelope curve of the frequency factor ( k ) based on a total of 10,194 station-years of annual maximum rainfall from 258 stations in Spain has been developed. This curve could be useful to estimate suitable values of PMP at any point of the Iberian Peninsula from basic statistical parameters (mean and standard deviation) of its rainfall series. [ABSTRACT FROM AUTHOR]

The relationship between maximum rainfall rates for time intervals between 5 min and 24 h has been studied from almost a century (1905-2003) of rainfall data registered in the Ebre Observatory (Tarragona, Spain). Intensity-duration-frequency (IDF) curves and their master equation for every return period in the location have been obtained, as well as the probable maximum precipitation (PMP) for all the considered durations. In particular, the value of the 1-day PMP has resulted to be 415 mm, very similar to previous estimations of this variable for the same location. Extreme rainfall events recorded in this period have been analyzed and classified according to their temporal scale. Besides the three main classes of cases corresponding to the main meteorological scales, local, mesoscale, and synoptic, a fourth group constituted by complex events with high-intensity rates for a large range of durations has been identified also, indicating the contribution of different scale meteorological processes acting together in the origin of the rainfall. A weighted intensity index taking into account the maximum rainfall rate in representative durations of every meteorological scale has been calculated for every extreme rainfall event in order to reflect their complexity. [ABSTRACT FROM AUTHOR]

The rainfall spatial organization in the metropolitan area of Barcelona (Spain) has been studied from records of an urban rain gauge network in the period 1994-2009. Using statistical and regional analysis techniques, correlation between data recorded by the different rain gauges has been calculated, and the effective number of independent stations ( n) equivalent to the used network has been determined. It has been found out that for durations longer than 20 min, the areal rainfall return period observed for a storm registered by the network approximately decreases by a factor of 1/ n in relation to the current point rainfall intensity-duration-frequency relationships for the metropolitan area of Barcelona. Using objective analysis techniques, continuous precipitation fields have been generated on a regular grid with a spatial resolution of 300 × 300 m for the storms registered by the rain gauges from 1994 to 2009, for durations from 10 min to 24 h. The precipitation fields obtained have been useful to estimate the characteristic areal reduction factors in the metropolitan area of Barcelona. A direct relationship has been found between the areal reduction factor for all the area corresponding to the urban rainfall network of Barcelona and the effective number of n for every duration considered. [ABSTRACT FROM AUTHOR]

From a large data set (1927-1992) of rainfall rate in Barcelona, the relationship between maximum rainfall rates for time intervals between 5 minutes and 24 hours has been investigated. Intensity-Duration-Frequency (IDF) curves and their master equation for every return period in Barcelona have been obtained. A cluster analysis has yielded four main classes of extreme rainfall events in this area, corresponding to durations shorter than 35 minutes, 1 hour, 2-6 hours and those longer than 6 hours respectively. An index to classify extreme rainfall events has been proposed. This index gives some information about the severity of storms taking into account the contribution of different scales implied in rainfall processes. [ABSTRACT FROM AUTHOR]

Convective rainfall rate distribution is not very uniform even at a local scale. In order to make an evaluation of it in the urban area of Barcelona, a dense rain gauge network has been stablished in this city. The gauges are of high resolution tilting bucket type. In this paper, preliminary results are presented. The distributions obtained show a strong variation of the rainfall rate for the several parts of the city. The intensity-duration curves for severe storms have been made in the various points of measure together with the areal reduction factors of rainfall. The analysis of raincell movement gives E-W as a predominant direction and a speed in the 3-12 m/s range. [ABSTRACT FROM AUTHOR]

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