Meteorological drought lacunarity around the world and its classification

The measure of drought duration strongly depends on the definition considered. In meteorology, dryness is habitually measured by means of fixed thresholds (e.g. 0.1 or 1 mm usually define dry spells) or climatic mean values (as is the case of the standardised precipitation index), but this also depends on the aggregation time interval considered. However, robust measurements of drought duration are required for analysing the statistical significance of possible changes. Herein we climatically classified the drought duration around the world according to its similarity to the voids of the Cantor set. Dryness time structure can be concisely measured by the n index (from the regular or irregular alternation of dry or wet spells), which is closely related to the Gini index and to a Cantor-based exponent. This enables the world’s climates to be classified into six large types based on a new measure of drought duration. To conclude, outcomes provide the ability to determine when droughts start and finish. We performed the dry-spell analysis using the full global gridded daily Multi-Source Weighted-Ensemble Precipitation (MSWEP) dataset. The MSWEP combines gauge-, satellite-, and reanalysis-based data to provide reliable precipitation estimates. The study period comprises the years 1979–2016 (total of 45 165 d), and a spatial resolution of 0.5∘, with a total of 259 197 grid pointsThis research has been supported by the European Research Council (RESCCUE (grant no. 700174)) and the Spanish Ministry of Science, Innovation and Universities (grant no. CGL2017-83866-C3-2-R). We are grateful for the support provided by the RESCCUE project, which received funding from the European Research Council under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 700174). We also wish to acknowledge the support received from the Spanish projects CGL2017-83866-C3-2-R and Climatology Group 2017 SGR 1362. We appreciate the interest in our research shown by the Water Research Institute of the University of Barcelona and by the Department of Algebra, Geometry and Topology of the Complutense University of MadridS

ALGUNAS REFLEXIONES Y EJEMPLOS DEL VALOR DE LA PERCEPCIÓN AMBIENTALEN LA PLANIFICACIÓN TERRITORIALY DE ACTIVIDADES

La percepción ambiental, es decir, cómo se percibe o se siente el medio ambiente (a partir del individuo inserto en él), tiene un notable interés psicológico y sociológico, pero también constituye una herramienta útil de análisis de la realidad para la planificación territorial y la programación de actividades. Aunque los resultados que la percepción suministre puedan, en ocasiones, discrepar abiertamente de la realidad, sirven al gestor y al planificador en la toma de decisiones adecuadas para la colectividad en sus relaciones con el marco físico

Language and Automata Theory and Applications

International audienc

CONCENTRAÇÃO DIÁRIA DA PRECIPITAÇÃO NA BACIA DO ALTO IGUAÇU, PARANÁ, BRASIL - CONCENTRATION INDEX OF RAINFALL IN THE UPPER BASIN IGUAÇU, PARANÁ, BRAZIL

A Bacia do Alto Iguaçu/Paraná, localizada no sul do Brasil, encontra-se exposta a riscos derivados das inundações, sobretudo nos meses de verão (dezembro, janeiro e fevereiro). Durante este período a bacia experimenta precipitações convectivas associadas a sistemas frontais juntamente com o aquecimento local. Además, as precipitações convectivas estão associadas com a entrada de umidade procedente do norte do Brasil. Dada a sua concentração e seu grande volume total, o conhecimento da precipitação em escala diária é essencial para o planejamento e gestão da bacia. Em particular, a compreensão dos padrões de precipitação diária torna-se essencial para o planejamento e gestão do território, assim como para a conservação dos recursos naturais. Com base no conhecimento da área de estudo, este trabalho utiliza o índice de concentração da precipitação (CI) para determinar os potencias impactos da precipitação diária. O índice foi aplicado para 18 estações meteorológicas com dados homogeneizados de qualidade, para o período de 1980 a 2010. Os valores foram calculados considerando os totais e a sazonalidade, com o intuito de verificar possíveis variações. Os valores do índice de concentração, foram altos durante o outono e inverno, já durante a primavera e o verão, apresentaram-se moderados.ABSTRACTThe Upper Iguaçu Basin/Paraná, located in the South of Brazil, is exposed to flood risk, mainly during summer months (December, January and February). During this period, the basin undergoes convective precipitation associated with frontal systems with local heating. Besides that, the convective precipitation is related to the moisture entrance from the North of Brazil. Given its concentration at time and large total volume, the knowledge of the resolution of daily rainfall is very important. Particularly, the comprehension of the daily rainfall patterns is essential for planning and management of land and to the conservation of natural resources. Based on area knowledge, this paper uses the concentration index (IC) to determine the potential impacts of daily rainfall. The index was applied in 18 meteorological stations within homogenized quality for the period 1970-2010. The values were calculated considering the the total amount and the sazonality, with the purpose of check possible variations.The values of the Concentration Index were high during fall and winter, and during summer and spring it reveals to be moderate

Future Projection of precipitation changes in the Júcar and Segura River Basins (Iberian Peninsula) by CMIP5 GCMs Local Downscaling

The basins of the Júcar and Segura rivers, on the Mediterranean coast of the Iberian Peninsula, present a special water problem and are of particular interest regarding climate change. These basins are very vulnerable to a possible scenario of decreasing water resources. Recent studies on historic rainfall since 1955 have indicated an ongoing loss of precipitation in their headwaters, especially in the case of the Júcar river. The aim of the present study is to perform climate projections for the precipitation variable for several future periods (2021-2040, 2051-2070, 2081-2100) and emission scenarios (RCPs 4.5, 8.5) within the Júcar and Segura River Basin authorities. For this purpose, a set of CMIP5 global models have been used, as well as the CDRD-HR-EIP-1955-2016 database, as a source of local observed information. This database comprises nearly 900 precipitation series in both basins and has been used in recent studies to determine historic trends of change in these basins. A statistical downscaling of the global models for all available observed series has been applied using the LARS-WG method. The results, although variable according to the CMIP5 model used, show the continuation of the patterns of precipitation change in the future, as already observed in the historical series. The results also predict a clear reduction in precipitation in the long term. However, torrential rainfall tends to increase in the coastal areas in relation to that observed in the short-term predictions. These results, due to their high spatial resolution, are of great interest for their use in small-scale hydrological and spatial planning (regional and local), which is one of the current challenges of climate modeling

Sediment Transport Capacity in a Gravel-Bed River with a Sandy Tributary

Data Availability Statement: Data sharing is not applicable to this article.Copyright © 2023 by the authors. Bedload transport in a river is a deeply analyzed problem, with many methodologies available in the literature. However, most of the existing methods were developed for reaches of rivers rather than for confluences and are suitable for a particular type of material, which makes them very inaccurate in cases where the sediments are comprised of a mix of different types of soil. This study considers the effect of two different bed sediment sizes, gravel and sand, in relation to bed load transport in a confluence. Five well-known and validated equations (namely Meyer-Peter and Müller, Parker + Engelund and Hansen, Ackers and White, and Yang) are applied to the case study of the Tagus–Alberche rivers confluence (in Talavera de la Reina, Spain), where main and tributary rivers transport different materials (sand and gravel). Field works in the area of the confluence were conducted, and a set of alluvial samples were collected and analyzed. The previously mentioned methods were employed to analyze the geomorphology in the confluence area and downstream of it under different flooding scenarios, concluding different trends in terms of deposition/erosion in the area under historic flooding scenarios. When the trends show erosion, all methods are very consistent in terms of numerical predictions. However, the results present high disparity in the estimated values when the predictions suggest deposition, with Parker + Engelund and Hansen yielding the highest volumes and Meyer-Peter and Müller the lowest (the latter being around 1% of the former). Yang and Ackers and White predict deposits in the same range in all cases (around 15% of Parker and Engelund Hansen). Yang’s formula was found to be suitable for the confluences of rivers with different materials, allowing for the estimation of sediment transport for different grain sizes. The effect of different flow regimes has been analyzed with the application of Yang’s formula to the Tagus-Alberche confluence.This research received no external funding

Serializing the Parallelism in Parallel Communicating Pushdown Automata Systems

We consider parallel communicating pushdown automata systems (PCPA) and define a property called known communication for it. We use this property to prove that the power of a variant of PCPA, called returning centralized parallel communicating pushdown automata (RCPCPA), is equivalent to that of multi-head pushdown automata. The above result presents a new sub-class of returning parallel communicating pushdown automata systems (RPCPA) called simple-RPCPA and we show that it can be written as a finite intersection of multi-head pushdown automata systems

Torrential rainfall in northeast of the Iberian Peninsula: synoptic patterns and WeMO influence

International audienceThis study presents a catalogue of synoptic patterns of torrential rainfall in northeast of the Iberian Peninsula (IP). These circulation patterns were obtained by applying a T-mode Principal Component Analysis (PCA) to a daily data grid (NCEP/NCAR reanalysis) at sea level pressure (SLP). The analysis made use of 304 days which recorded >100 mm in one or more stations in provinces of Barcelona, Girona and Tarragona (coastland area of Catalonia) throughout the 1950?2005 period. The catalogue comprises 7 circulation patterns showing a great variety of atmospheric conditions and seasonal or monthly distribution. Likewise, we computed the mean index value of the Western Mediterranean Oscillation index (WeMOi) for the synoptic patterns obtained by averaging all days grouped in each pattern. The results showed a clear association between the negative values of this teleconnection index and torrential rainfall in northeast of the IP. We therefore put forward the WeMO as an essential tool for forecasting heavy rainfall in northeast of Spain