Gilles Lajoie

• Research Director at University of Reunion Island

En s’appuyant sur l’analyse des presses locales et nationales (Le Quotidien, Le JIR, Témoignages ; Le Monde), sur divers documents institutionnels (Chartes des JOI, P.V. des réunions du Conseil International des Jeux (CIJ), correspondances CNOSF et CROS…) et l’expérience d’un grand témoin, ancien président du Comité Régional Olympique et Sportif de...

Numerical weather prediction models tend to underestimate cloud presence and therefore often overestimate global horizontal irradiance (GHI). The assimilation of cloud water path (CWP) retrievals from geostationary satellites using an ensemble Kalman filter (EnKF) led to improved short-term GHI forecasts of the Weather Research and Forecasting (WRF...

Environmental factors shape the spatial distribution and dynamics of populations. Understanding how these factors interact with movement behavior is critical for efficient conservation, in particular for migratory species. Adult female green sea turtles, Chelonia mydas, migrate between foraging and nesting sites that are generally separated by thou...

Numerical weather prediction models tend to underestimate cloud presence and therefore often overestimate global horizontal irradiance (GHI). The assimilation of cloud water path (CWP) retrievals from geostationary satellites using an ensemble Kalman filter (EnKF) led to improved short-term GHI forecasts of the Weather Research and Forecasting (WRF...

Article publié en anglais (p. 2-8), avec un résumé étendu en français (p.9-10) et 2 planches couleur hors-texte (p.55-56)

Many research and societal applications such as surface solar irradiance assessment and forecasting require accurate short-term cloudiness forecasts at kilometre and hourly scales. Today limited-area numerical weather prediction models have the potential to provide such forecasts by simulating clouds at high spatial and temporal resolutions. Howeve...

Reunion Island is a French oversea territory located in Indian Ocean. With an installed photovoltaic capacity of 173.1 MW, the solar energy represents sometimes more than 30% of the available power. Because this abundant energy is highly variable, grid networks managers require day-ahead PV production forecasts in order to plan and secure the energ...

More accurate short-term solar irradiance forecasts are required to enable an increased feed-in of photovoltaic power to non-interconnected electricity grids. Achieving higher forecast accuracy is particularly challenging in the case of Tropical Islands due to the lack of distinct large-scale horizontal gradients of thermodynamic fields as in mid-l...

Although the high amount of solar irradiance in the tropics is an advantage for a profitable PV production, the local meteorological conditions induce a very high variability which is problematic for a safe and gainful injection into the power grid. This issue is even more critical in non-interconnected territories where network stability is an abs...

The invasive Asian tiger mosquito, Aedes albopictus, has been established on the French overseas island of Mayotte in the Indian Ocean since 2007. Despite the presence of a resident population of Aedes aegypti, Ae. albopictus has expanded its presence in urban areas, in contrast to the pattern of invasion by this mosquito elsewhere in the world. We...

IntroductionA few major theoretical breakthroughs for modeling spatial complexityModeling and territorial forecasting of the socio-spatial system of RéunionModeling of Réunion's socio-spatial systemTowards a modeling of the dynamics of Réunion's systemConclusion Bibliography

How can scientists help institutions and local stakeholders be more involved in land use and territorial management processes? Decentralization of land use management is far from complete in Senegal and La Réunion Island. Despite exhaustive legislation, local populations remain little involved in the decisions that affect their land. This is partly...

This paper introduces a methodological framework for performance assessment of spatial dynamic models by means of map comparison. The objective is to discern to what extent model performance, expressed by a variety of metrics, can be attributed to endogenously modeled processes or to exogenous model inputs. For this purpose, neutral models of lands...

After having set out the challenges connected with land ownership and real estate in the insular, micro context of Reunion Island, we plan to create a robot land-use model based on satellite images integrated with a cellular robot. Once the general framework of the modelling has been established, we will make the case for calibrating the cellular r...

After having set out the challenges connected with land ownership and real estate in the insular, micro context of Reunion Island, we plan to create a robot land-use model based on satellite images integrated with a cellular robot. Once the general framework of the modelling has been established, we will make the case for calibrating the cellular r...

About measurement in social geography. — Measurement is the necessary way towards a scientific approach. Appropriate measurement methods may be used in various geographical matters, such as the optimal location of public services, the pattern of transportation networks, GIS for environmental monitoring or policy simulations, etc. The bias in the ch...

Dans le cadre d'une cartographie par carroyage, on étudie la désagrégation de variables zonales, en revenant sur l'hypothèse de l'équirépartition spatiale des populations. L'objectif est d'approcher des règles différenciées de désagrégation des variables en fusionnant des plans d'information de nature morphologique, topologique et environnementale.

Using grid mapping, we examine the desagregation of areas variables, by reverting to the hypothesis of spatial equirepartition of population. The goal is to approximate the differenciated rules of variables desagregation by combining different informations, the nature of which is either morphological, topological or environmental.

The study of artefacts collected in the flowof the Seine river, below its confluence with the Eure river, brings knowledges about the seulement of the Lower Seine Valley from the Neolithic to historical times. The ground of the study is a non exhauxive inventory of recent discoveries in sediments dredged in the river. We have choosed organic artefa...

A set of analysis modules with interactive control and integrated in SIGUR covers both pointwise, linear and zonal geographic data representation models. The modules provide mathematical and statistical analyses and graphical representations. These possibilities are demonstrated in practical analysis examples for Rouen, Le Havre and Elbeuf. -R.Hard...

Pour une comparaison rigoureuse de l’espace rouennais, les auteurs proposent, au lieu du maillage changeant des îlots ou quartiers, un maillage fixe de carrés de 250 m de côté où les données sont transférées par calcul. Cette procédure («grid map» des Britanniques) autorise des traitements statistiques moins biaisés.

The system of automatic "mailing' is a methodology with which it's possible to localize exactly each data of a listing. The cartography made by quadrat mapping and a relation "streets - square' is managed by a program. By with methodology, a better geographical analysis is possible. -English summary

Résumé En matière d'aménagement du territoire, l'île de La Réunion est confrontée au défi d'accueillir une population de plus en plus importante tout en valorisant son terroir agricole et en proté-geant ses paysages exceptionnels. Dans un tel contexte, faire de la prospective territoriale, et en ce sens parvenir à modéliser et simuler des comportem...