Data sources for rescuing the rich heritage of Mediterranean historical surface climate data

10.1002/gdj3.4Availability of long-term and high-quality instrumental climate records is still insufficient and the rich heritage of meteorological surface observations is largely underexploited in many parts of the world. This is particularly striking over the Greater Mediterranean region (GMR), where meteorological observations have been taken since the 18th century at some locations. The lack of high quality and long series here is despite this region being regarded as a climate change hot spot. This article mainly assesses relevant sources containing Mediterranean historical climate data and metadata either from online repositories worldwide or physical archives, with the emphasis here on the rich holdings kept at French archives. A particular case study is the data rescue (DARE) program undertaken by the Algerian National Meteorological Service, as well as some of the past and ongoing projects and initiatives aimed at enhancing climate data availability and accessibility over the GMR. Our findings point to the high potential for undertaking DARE activities over the GMR and the need for bringing longer and higher quality climate time series to support a diverse number of scientific and technical assessments and policies

Stationarity analysis of historical flood series in France and Spain (14th–20th centuries)

International audienceInterdisciplinary frameworks for studying natural hazards and their temporal trends have an important potential in data generation for risk assessment, land use planning, and therefore the sustainable management of resources. This paper focuses on the adjustments required because of the wide variety of scientific fields involved in the reconstruction and characterisation of flood events for the past 1000 years. The aim of this paper is to describe various methodological aspects of the study of flood events in their historical dimension, including the critical evaluation of old documentary and instrumental sources, flood-event classification and hydraulic modelling, and homogeneity and quality control tests. Standardized criteria for flood classification have been defined and applied to the Isère and Drac floods in France, from 1600 to 1950, and to the Ter, the Llobregat and the Segre floods, in Spain, from 1300 to 1980. The analysis on the Drac and Isère data series from 1600 to the present day showed that extraordinary and catastrophic floods were not distributed uniformly in time. However, the largest floods (general catastrophic floods) were homogeneously distributed in time within the period 1600–1900. No major flood occurred during the 20th century in these rivers. From 1300 to the present day, no homogeneous behaviour was observed for extraordinary floods in the Spanish rivers. The largest floods were uniformly distributed in time within the period 1300–1900, for the Segre and Ter rivers

Solvent-Induced Reversal of Activities between Two Closely Related Heterogeneous Catalysts in the Aldol Reaction

The relative rates of the aldol reaction catalyzed by supported primary and secondary amines can be inverted by 2 orders of magnitude, depending on the use of hexane or water as a solvent. Our analyses suggest that this dramatic shift in the catalytic behavior of the supported amines does not involve differences in reaction mechanism, but is caused by activation of imine to enamine equilibria and stabilization of iminium species. The effects of solvent polarity and acidity were found to be important to the performance of the catalytic reaction. This study highlights the critical role of solvent in multicomponent heterogeneous catalytic processes

When urban modernisation entails service delivery co-production: a glance from Medellin

International audienceThrough the example of Ciudadela Nuevo Occidente, a large social housing district in Medellín, this article describes a process that primarily involves co-learning and micro-negotiations that help produce the cognitive alignment necessary to the management of services. The hypothesis put forward in this article is that the frictions caused by the residents' difficulties in adapting to the socioeconomic , cultural and cognitive frameworks of their new environment, imposed by urban modernisation running processes, engender forms of service co-production that ultimately strengthen the utility's capacity to extend and adapt its delivery model while enhancing the quality of services

Utilisation de l'information des crues historiques pour une meilleure prédétermination du risque d'inondation. Application au bassin de l'Ardèche à Vallon-Pont-d'Arc et St-Martin-d'Ardèche

The thesis deals with the use of historical flood information to improve flood risk estimation. The problem us presented in introduction and after this report is divided into four parts. Chapter 2 presents the various data exploitable in flood frequency analysis (FFA). Prehistoric, historical and contemporary information are discussed. Actual means to collect this data and problems involved in its use are also presented. The formalization of the flood data for exploitation in statistical framework is then tackled. Chapter 3 deals with FFA when historical data are taken into account and presents a synthesis of existing methods. A generalized formulation for the method based on Maximum likelihood estimators within the framework pf the annual maximum flood series was developed. An adaptation of the expected moment algorithm to EV1 and GEV distributions is also carried out. Methods adapted to peak over threshold series are presented afterwards. Some comments are also carried out on plotting position and measurement errors.Cette thèse aborde l'exploitation de l'information historique pour améliorer la prédétermination du risque d'inondation. Après avoir présenté la problématique en introduction, ce rapport se décompose en quatre parties. Le chapitre 21 présente les différentes données exploitables dans l'analyse fréquentielle des crues. Les informations préhistoriques, historiques et contemporaines sont abordées en détaillant d'une part les moyens disponibles pour les obtenir et d'autre part les problèmes liés à leur utilisation. La formalisation des données sur les crues en vue de leur exploitation dans l'analyse fréquentielle est ensuite abordée. Le chapitre 3 aborde l'analyse fréquentielle des crues avec la prise en compte des données historiques et présente une synthèse des méthodes existantes. Une formulation généralisée est présentée pour la méthode du maximum de vraisemblance dans le cadre de séries de valeurs maximales annuelles. Une adaptation de la méthode des moments espérés a été effectuée pour deux nouvelles distributions (EV1 et GEV). Les méthodes adaptées aux séries de valeurs supérieures à un seuil sont ensuite présentées. Quelques commentaires sont données sur l'estimation des probabilités empiriques et la prise en compte des erreurs de mesure sur les débits. Le chapitre 4 traite de l'inventaire et de la collecte des données historiques sur les inondations au travers d'une étude de cas sur l'Ardèche. La méthodologie Historique, qui repose sur une collaboration entre historiens et hydrologues, a été testée et améliorée pendant cette application. Les principaux résultats obtenus sur le bassin étudié sont présentés. Le chapitre 5 présente l'exploitation de l'information historique sur deux secteurs du bassin de l'Ardèche. Les données limnimétriques collectées sont critiquées puis converties en débits par une modélisation hydraulique monodimensionnelle. Une vérification de la stationnarité des séries reconstituées est effectuée avant d'estimer les quantiles de crue. Une comparaison des résultats obtenus en exploitant soit l'information historique, soit l'information pluviométrique (méthode du Gradex) montre une bonne cohérence. En guise de conclusion, nous dressons un bilan du travail réalisé et ouvrons des perspectives pour la poursuite des recherches sur la prise en compte de l'information des crues historiques

Valorisation de l'information historique pour la prédétermination du risque d'inondation : application au bassin du Guiers

La collaboration entre historiens, archivistes et hydrologues permet de valoriser l'information historique sur les inondations, et ainsi de mieux estimer le risque d'inondation. Cette démarche « Historisque » a été initiée en 1996 sur le bassin du Guiers, qui présente l'intérêt d'être bien documenté sur la période du XVIII ème au XIXème siècle. Cette rivière constituait en effet l'ancienne frontière entre la France et la Savoie, et a fait l'objet au XVIIIème et XIXeme siècle de nombreux rapports pour fixer les limites entre les deux territoires. Il a été possible, à partir du dépouillement de plus de 200 actes d'archives, de dresser une chronologie qualitative des crues depuis la seconde moitié du XVIIIeme siècle, de proposer un guide-inventaire des sources d'archives sur les inondations, et d'illustrer la méthodologie Historisque au travers de la reconstitution du débit de la crue de juin 1875 du Guiers à Pont-de-Beauvoisin. / Collaboration between historians, archivists and hydrologists can provide a significant improvement in the field of flood hazard studies, by using historical information about floods. This Historisk methodology was first applied in 1996 on river Guiers, which has a good historical information during the 18th and 19th centuries. This river was the old borderline between France and Savoy, and so many reports are available and concern the boundaries of the two areas. The analysis of more than two hundred archives allows the qualitative collection of the most important floods since the second part of the 18th century, and the establishment of a guide, which presents the different archive sources about floods. An example of the Historisk methodology is carried out by estimating the discharge of the 1875 flood on river Guiers at Pont-de-Beauvoisin

Stationarity analysis of historical flood series in France and Spain (14th-20th centuries)

Interdisciplinary frameworks for studying natural hazards and their temporal trends have an important potential in data generation for risk assessment, land use planning, and therefore the sustainable management of resources. This paper focuses on the adjustments required because of the wide variety of scientific fields involved in the reconstruction and characterisation of flood events for the past 1000 years. The aim of this paper is to describe various methodological aspects of the study of flood events in their historical dimension, including the critical evaluation of old documentary and instrumental sources, flood-event classification and hydraulic modelling, and homogeneity and quality control tests. Standardized criteria for flood classification have been defined and applied to the Isère and Drac floods in France, from 1600 to 1950, and to the Ter, the Llobregat and the Segre floods, in Spain, from 1300 to 1980. The analysis on the Drac and Isère data series from 1600 to the present day showed that extraordinary and catastrophic floods were not distributed uniformly in time. However, the largest floods (general catastrophic floods) were homogeneously distributed in time within the period 1600¿1900. No major flood occurred during the 20th century in these rivers. From 1300 to the present day, no homogeneous behaviour was observed for extraordinary floods in the Spanish rivers. The largest floods were uniformly distributed in time within the period 1300-1900, for the Segre and Ter rivers

Dynamics of particulate organic matter d15N and d13C during spring phytoplankton blooms in a macrotidal ecosystem (Bay of Seine, France)

International audienceTwo cruises (April and June 1997) were carried out in the Bay of Seine, a nitrate- and ammonium-enriched ecosystem of Western Europe, to identify the major mechanisms that control δ15N and δ13C in spring particulate organic matter (POM). Particulate organic nitrogen (PON) δ15N ranged between 0.8 and 5.2‰ in April and between 2.2 and 6.2‰ in June, while particulate organic carbon (POC) δ13C ranged between -24.3 and -19.7‰, and between -20.0 and -16.2‰ during the same periods. During spring 1997, POM was highly dominated by autochthonous phytoplankton. It is shown that the variation of PON δ15N is due to both nitrate mixing between river and marine waters and fractionation of N stable isotopes during nitrate utilization by phytoplankton. Therefore, similarly to what was previously shown for open ocean, δ15N can be used as a proxy of spring fractional nitrate utilization in coastal ecosystems. It is also shown that POC δ13C in spring is controlled by POC concentration and C:N ratio (in addition to Œtemperature effects¹), which are considered here as indicators of primary production and phytoplankton degradation, respectively. The co-variation of δ13C and δ15N describes the spring phytoplankton dynamics: at the start of phytoplankton development, nitrate concentration is high (low δ15N) and phytoplankton production is low (low δ13C); then primary production increases (δ13C becomes higher) and the nitrate pool diminishes (δ15N becomes higher); at a later stage, the nitrate pool is depleted (high δ15N), part of the phytoplankton becomes degraded and production is still high (high δ13C)

Dynamics of particulate organic matter d¹⁵N and d¹³C during spring phytoplankton blooms in a macrotidal ecosystem (Bay of Seine, France)

Two cruises (April and June 1997) were carried out in the Bay of Seine, a nitrate- and ammonium-enriched ecosystem of Western Europe, to identify the major mechanisms that control d15N and d13C in spring particulate organic matter (POM). Particulate organic nitrogen (PON) d15N ranged between 0.8 and 5.2‰ in April and between 2.2 and 6.2‰ in June, while particulate organic carbon (POC) d13C ranged between –24.3 and –19.7‰, and between –20.0 and –16.2‰ during the same periods. During spring 1997, POM was highly dominated by autochthonous phytoplankton. It is shown that the variation of PON d15N is due to both nitrate mixing between river and marine waters and fractionation of N stable isotopes during nitrate utilization by phytoplankton. Therefore, similarly to what was previously shown for open ocean, d15N can be used as a proxy of spring fractional nitrate utilization in coastal ecosystems. It is also shown that POC d13C in spring is controlled by POC concentration and C:N ratio (in addition to ‘temperature effects’), which are considered here as indicators of primary production and phytoplankton degradation, respectively. The co-variation of d13C and d15N describes the spring phytoplankton dynamics: at the start of phytoplankton development, nitrate concentration is high (low d15N) and phytoplankton production is low (low d13C); then primary production increases (d13C becomes higher) and the nitrate pool diminishes (d15N becomes higher); at a later stage, the nitrate pool is depleted (high d15N), part of the phytoplankton becomes degraded and production is still high (high d13C)