A framework for the analysis of the influence of rainfall spatial organization and basin morphology on flood response

This work describes the derivation of a set of statistics, termed spatial moments of catchment rainfall, that quantify the dependence between rainfall spatial organization, basin morphology and runoff response. These statistics describe the spatial rainfall organisation in terms of concentration and dispersion along the flow distance coordinate. These statistics were derived starting from an analytical framework, and related with the statistical moments of the flood hydrograph. From spatial moments we also created an index quantifying catchment scale storm velocity. This index measures the overall movement of the rainfall system over the catchment, reflecting the filtering effect of its morphology. We also extended spatial moments to the hillslope system, developing a framework to evaluate the relevance of hillslope and channel propagation in the flood response to spatially variable rainfall fields. Data from six flash floods occurred in Europe between 2002 and 2007 are used to evaluate the information provided by the framework. High resolution radar rainfall fields and a distributed hydrologic model are employed to examine how effective are these statistics in describing the degree of spatial rainfall organisation, which is important for runoff modelling. The size of the study catchments ranges between 36 to 2586 km2. The analysis reported here shows that spatial moments of catchment rainfall can be effectively employed to isolate and describe the features of rainfall spatial organization which have significant impact on runoff simulation. Rainfall distribution was observed to play an important role in catchments as small as 50 km2. The description timing error was further improved by the inclusion in the framework of hillslope propagation. This development allows to compare scenarios of hillslope conditions, to evaluate the sensitivity of single basins or the effect of catchment scale. The analysis of catchment scale storm velocity showed a nonlinear dependence with basin scale. The values of velocity observed were however rather moderate, in spite of the strong kinematic characteristics of individual storm elements, and did not play a relevant effect on the flood analyzed

A framework for the analysis of the influence of rainfall spatial organization and basin morphology on flood response

This work describes the derivation of a set of statistics, termed spatial moments of catchment rainfall, that quantify the dependence between rainfall spatial organization, basin morphology and runoff response. These statistics describe the spatial rainfall organisation in terms of concentration and dispersion along the flow distance coordinate. These statistics were derived starting from an analytical framework, and related with the statistical moments of the flood hydrograph. From spatial moments we also created an index quantifying catchment scale storm velocity. This index measures the overall movement of the rainfall system over the catchment, reflecting the filtering effect of its morphology. We also extended spatial moments to the hillslope system, developing a framework to evaluate the relevance of hillslope and channel propagation in the flood response to spatially variable rainfall fields. Data from six flash floods occurred in Europe between 2002 and 2007 are used to evaluate the information provided by the framework. High resolution radar rainfall fields and a distributed hydrologic model are employed to examine how effective are these statistics in describing the degree of spatial rainfall organisation, which is important for runoff modelling. The size of the study catchments ranges between 36 to 2586 km2. The analysis reported here shows that spatial moments of catchment rainfall can be effectively employed to isolate and describe the features of rainfall spatial organization which have significant impact on runoff simulation. Rainfall distribution was observed to play an important role in catchments as small as 50 km2. The description timing error was further improved by the inclusion in the framework of hillslope propagation. This development allows to compare scenarios of hillslope conditions, to evaluate the sensitivity of single basins or the effect of catchment scale. The analysis of catchment scale storm velocity showed a nonlinear dependence with basin scale. The values of velocity observed were however rather moderate, in spite of the strong kinematic characteristics of individual storm elements, and did not play a relevant effect on the flood analyzed.Questo lavoro presenta una serie di statistici, denominati "momenti spaziali di pioggia a scala di bacino", che permettono di quantificare la relazione tra l’organizzazione spaziale della pioggia, la morfologia del bacino e la forma dell’idrogramma di piena. Tali statistici descrivono la posizione e la dispersione della pioggia su un assegnato bacino idrografico. La trattazione include la derivazione di una serie di relazioni che consentono di stabilire un rapporto fra detti statistici di pioggia ed i momenti temporali dell’onda di piena. La formulazione complessiva del lavoro consente di isolare e quantificare l’effetto della variabilità spaziale della pioggia sulla struttura della risposta di piena, e di creare un indice di velocità del sistema di pioggia. Questo indice considera l'iterazione tra morfologia del bacino e spostamento della pioggia, quantificando l'influenza sull'idrogramma. I momenti spaziali stati poi ampliati alla propagazione su versante, sviluppando degli statistici per valutare l'importanza della propagazione di canale e di versante sulla risposta nella riposta di un bacino ad una pioggia distribuita. Dati relativi a sei eventi estremi di piena improvvisa verificatisi in diverse regioni Europee sono utilizzati per illustrare il significato degli statistici e le relazioni con la forma dell'idrogramma. Stime di pioggia da radar ed un modello idrologico distribuito sono utilizzati per valutare l'efficacia degli statistici nel cogliere l'organizzazione delle piogge che ha un'influenza sulla simulazione di piena. Lo studio mostra che i momenti spaziali di pioggia a scala di bacino possono essere efficaci nel cogliere questa organizzazione. Nelle piene improvvise analizzate la distribuzione della pioggia ha un effetto rilevante anche per bacini di circa 50 km2. La descrizione dell'errore temporale dell'idrogramma è ulteriormente migliorata dalla considerazione dell'effetto del versante. Questo sviluppo permette inoltre di confrontare condizioni di versante diverse, di valutare la suscettibilità di singoli bacini o l'effetto in relazione alla scala dei bacini. L'analisi della velocità di spostamento a scala di bacino mostra una relazione non lineare con le dimensioni del bacino. I valori di velocità osservati sono comunque moderati, nonostante la forte velocità di spostamento delle singole celle convettive, e non hanno avuto un ruolo rilevante nell'evento analizzato

Détailler l’approbation éthique dans les articles scientifiques pour prévenir, détecter et investiguer la fraude : Analyse et considérations autour d’un exemple de stratégie éditoriale

En 2011 une fraude massive a frappé le milieu de l’édition biomédicale: plusieurs études publiées avec une mention d’approbation éthique n’avaient en réalité jamais été soumises à un comité d’éthique. Ces faits avaient conduit le European Journal of Anaesthesiology à adopter une mesure éditoriale visant à faciliter l’identification et le contact avec les comités éthiques dans le but de prévenir de telles situations. Cette thèse s’attache à évaluer l’efficacité de cette stratégie, qui s’avère perfectible. L’analyse a été publiée en mai 2018 dans un journal à politique éditoriale et est ici reproduite dans sa version originale. Nous y ajoutons un examen du rationnel qui a guidé à sa conception et une introduction retraçant la genèse des interrogations bioéthiques dans le monde occidental jusqu’à la mise en place de comités éthiques. Notre synthèse questionne enfin leur rôle dans la détection et la prévention de la fraude

Identification of ethics committees based on authors’ disclosures: cross-sectional study of articles published in the European Journal of Anaesthesiology and a survey of ethics committees

Abstract Background Since 2010, the European Journal of Anaesthesiology has required the reporting of five items concerning ethical approval in articles describing human research: ethics committee’s name and address, chairperson’s name, study’s protocol number and approval date. We aimed to assess whether this requirement has helped to identify and to contact the referenced ethics committees. Methods In this cross-sectional study, we analysed articles requiring ethical approval, according to the Swiss federal law for human research and published in the European Journal of Anaesthesiology in 2011. Ethics committees were searched through our institutional Internet access based on information provided in the articles. The last search was performed in November 2015. Numbers (%) of items reported, of ethics committees identified, and of those that confirmed having provided ethical approval are reported. Results Of 76 articles requiring ethical approval, 74 (97%) declared it. Ethics committees’ names and addresses were mentioned in 63/74 (85%), protocol numbers in 51/74 (69%), approval dates in 48/74 (65%), and chairpersons’ names in 45/74 (61%). We could identify 44/74 (59%) committees; 36/74 (49%) answered our inquiry and 24/74 (32%) confirmed their role. Thirty-four of 74 articles (46%) reported all five items; in 25/34 (74%), we were able to identify an ethics committee, 18/34 (53%) answered our inquiry, and 15/34 (44%) confirmed their role. Forty of 74 articles (54%) reported ≤4 items; in 19/40 (48%), we were able to identify an ethics committee, 18/40 (45%) answered our inquiry, and 9/40 (23%) confirmed their role. Reporting five items significantly increased identification of ethics committees (p = 0.023) and their confirmation of ethical approval (p = 0.048). Twelve of 74 ethics committees (16%) were unable to confirm their role in approving the study. Conclusions Even when details concerning ethical approval were reported in these studies of human research, we were unable to identify almost half of the ethics committees concerned. The reporting of five items, compared with reporting ≤4, was associated with facilitated identification of ethics committees, and increased the likelihood that they would be able to confirm the study’s approval. Future research should identify which information facilitates identification of, and contact with, ethics committees

Controls of flash flood peak discharge in Mediterranean basins and the special role of runoff-contributing areas

During the complex dynamic interactions between rainfall and basin properties, different portions of the basin produce runoff at different moments. Capturing this spatiotemporal variability is important for flood analysis, but knowledge of this subject is limited. The presented research aims at improving the understanding of runoff contributing areas (RCA; hillslope sections from which water flows, reaches the stream network, and consequently the basin outlet) and at examining their relationship with the magnitude of a flash flood's peak discharge. A distributed hydrological model (GB-HYDRA) that enables computing RCA and flood discharge was developed. The model was applied to four medium-size basins (18-69 km(2)) in a Mediterranean climate and 59 flash flood events were analyzed. The correlation between basin input flux (basin area multiplied by the basin maximal rain intensity averaged over the time of concentration) and output flux (observed peak discharge) was poor (R-2 = 0.16). However, using a newly developed index, termed IRCA, to calculate the input flux accounting only for the RCA extent and rainfall intensity over it, resulted in a substantially higher correlation (R-2 = 0.64) across a wide range of flood magnitudes. The highest correlation was found using a 50-min time window, which is shorter than the time of concentration. Flood events were categorized according to their magnitude and the differences of several factors among the groups were examined. Pre-storm soil moisture content was found to be similar for all event magnitudes; however, pre-peak soil moisture content was substantially different between moderate and large extreme events. Other important properties that differed between magnitudes were: RCA extent and its averaged rain intensity and ratio of convective rainfall. Finally, areas with land-uses characterized by low runoff potential became dominant and contributed mainly during large and extreme events. Although the RCA and its extent full potential is yet to be fulfilled, it is proposed as a significant tool for understanding processes of flash flood generation at the basin scale in future research