Selection of intense rainfall events based on intensity thresholds and  lightning data in Switzerland

Gaál, Ladislav; Molnár, Péter; Szolgay, Ján

doi:10.5194/hess-18-1561-2014

Cited by 52 publications

(51 citation statements)

References 62 publications

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“…might allow us to have a better understanding of the whole hydrological regime which could be used to more accurately sort the database. For example, a recent study by Gaál et al (2014) suggested the use of lightning data as an indicator of convectivity in rainfall events. Additionally, there are other climatic indicators related to the energy and water balance, such as the aridity index (ratio between potential evapotranspiration and mean annual precipitation), that could provide together with rainfall and temperature valuable information on the climate type.…”

Section: Discussionmentioning

confidence: 99%

Regional parent flood frequency distributions in Europe – Part 2: Climate and scale controls

Salinas

Castellarin

Kohnová³

et al. 2014

Hydrol. Earth Syst. Sci.

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Abstract. This study aims to better understand the effect of catchment scale and climate on the statistical properties of regional flood frequency distributions. A database of Lmoment ratios of annual maximum series (AMS) of peak discharges from Austria, Italy and Slovakia, involving a total of 813 catchments with more than 25 yr of record length is presented, together with mean annual precipitation (MAP) and basin area as catchment descriptors surrogates of climate and scale controls. A purely data-based investigation performed on the database shows that the generalized extreme value (GEV) distribution provides a better representation of the averaged sample L-moment ratios compared to the other distributions considered, for catchments with medium to higher values of MAP independently of catchment area, while the three-parameter lognormal distribution is probably a more appropriate choice for drier (lower MAP) intermediate-sized catchments, which presented higher skewness values. Sample L-moment ratios do not follow systematically any of the theoretical two-parameter distributions. In particular, the averaged values of L-coefficient of skewness (L-Cs) are always larger than Gumbel's fixed L-Cs. The results presented in this paper contribute to the progress in defining a set of "process-driven" pan-European flood frequency distributions and to assess possible effects of environmental change on its properties.

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Section: Discussionmentioning

confidence: 99%

Regional parent flood frequency distributions in Europe – Part 2: Climate and scale controls

Salinas

Castellarin

Kohnová³

et al. 2014

Hydrol. Earth Syst. Sci.

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“…These are all 10 min precipitation depths, with 0.1 mm resolution, measured over the exact same period with the same Lambrecht tippingbucket instruments, with standardized calibration and maintenance. These rainfall data are of very good quality and have recently been used in other studies of storm properties in Switzerland (e.g., Gaál et al, 2014;Molnar et al, 2015).…”

Section: Study Sites and Datamentioning

confidence: 99%

“…Although there are many different approaches for selecting a criterion for event independence (e.g., Dunkerley, 2008), we chose to discriminate successive independent storms based on a minimum inter-event time, MIT (Restrepo-Posada and Eagleson, 1982;Driscoll et al, 1989;Gaál et al, 2014). With this scheme, any dry spell (i.e., between recorded precipitation) longer than the MIT defines two independent storms.…”

Section: Event Definitionmentioning

confidence: 99%

Describing the interannual variability of precipitation with the derived distribution approach: effects of record length and resolution

Meier

Moraga

Pranzini

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract. Interannual variability of precipitation is traditionally described by fitting a probability model to yearly precipitation totals. There are three potential problems with this approach: a long record (at least 25-30 years) is required in order to fit the model, years with missing rainfall data cannot be used, and the data need to be homogeneous, i.e., one has to assume stationarity. To overcome some of these limitations, we test an alternative methodology proposed by Eagleson (1978), based on the derived distribution (DD) approach. It allows estimation of the probability density function (pdf) of annual rainfall without requiring long records, provided that continuously gauged precipitation data are available to derive external storm properties. The DD approach combines marginal pdfs for storm depths and inter-arrival times to obtain an analytical formulation of the distribution of annual precipitation, under the simplifying assumptions of independence between events and independence between storm depth and time to the next storm. Because it is based on information about storms and not on annual totals, the DD can make use of information from years with incomplete data; more importantly, only a few years of rainfall measurements should suffice to estimate the parameters of the marginal pdfs, at least at locations where it rains with some regularity.For two temperate locations in different climates (Concepción, Chile, and Lugano, Switzerland), we randomly resample shortened time series to evaluate in detail the effects of record length on the DD, comparing the results with the traditional approach of fitting a normal (or lognormal) distribution. Then, at the same two stations, we assess the biases introduced in the DD when using daily totalized rainfall, instead of continuously gauged data. Finally, for randomly selected periods between 3 and 15 years in length, we conduct full blind tests at 52 high-quality gauging stations in Switzerland, analyzing the ability of the DD to estimate the longterm standard deviation of annual rainfall, as compared to direct computation from the sample of annual totals.Our results show that, as compared to the fitting of a normal or lognormal distribution (or equivalently, direct estimation of the sample moments), the DD approach reduces the uncertainty in annual precipitation estimates (especially interannual variability) when only short records (below 6-8 years) are available. In such cases, it also reduces the bias in annual precipitation quantiles with high return periods. We demonstrate that using precipitation data aggregated every 24 h, as commonly available at most weather stations, introduces a noticeable bias in the DD. These results point to the tangible benefits of installing high-resolution (hourly, at least) precipitation gauges, next to the customary, manual rain-measuring instrument, at previously ungauged locations. We propose that the DD approach is a suitable tool for the statistical description and study of annual rainfall, not only when short records ...

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“…Precipitation is a major cause of natural hazards and is related to flooding [1][2][3]. The severity of a precipitation event and its potential damage is dependent on the total amount of rain and also on its intensity and duration [1].…”

Section: Introductionmentioning

confidence: 99%

Precipitation Thresholds for Triggering Floods in the Corgo Basin, Portugal

Santos

Fragoso

2016

Water

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Thresholds based on critical combinations of amount/duration of precipitation and flood events were estimated for the Corgo hydrographic basin, in northern Portugal. Thirty-one flood events in the Corgo basin were identified between 1865 and 2011 from a database of hydrometeorological disasters in Portugal. The minimum, maximum, and pre-warning thresholds that define the boundaries for flood occurrence were determined. The results show that the ratio between the total number of floods and precipitation events exceeding the minimum threshold denotes a relatively low probability of successful forecasting. This result may be due to the reduced number of flooding events in the floods database, which only include floods that caused damage as reported by the media. The estimated maximum threshold is not adequate for use in floods, since the majority of true positives are below this limit. However, and more interestingly, the retrospective verification of the estimated thresholds suggests that the minimum and pre-warning thresholds are well adjusted. Therefore, the application of these precipitation thresholds may contribute to minimize possible situations of pre-crisis or immediate crisis by reducing the flood consequences and the resources involved in emergency response to flood events.

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Selection of intense rainfall events based on intensity thresholds and lightning data in Switzerland

Cited by 52 publications

References 62 publications

Regional parent flood frequency distributions in Europe – Part 2: Climate and scale controls

Regional parent flood frequency distributions in Europe – Part 2: Climate and scale controls

Describing the interannual variability of precipitation with the derived distribution approach: effects of record length and resolution

Precipitation Thresholds for Triggering Floods in the Corgo Basin, Portugal

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