Within the context of an ecosystem approach for fisheries, there is a need for quantitative information on distributions of key marine species. This information is valuable input for modelling species interactions in the southern Benguela ecosystem. In the present study, a method is described for mapping the density distribution of 15 key species: anchovy Engraulis encrasicolus, sardine Sardinops sagax, round herring Etrumeus whiteheadi, chub mackerel Scomber japonicus, horse mackerel Trachurus trachurus capensis, lanternfish Lampanyctodes hectoris, lightfish Maurolicus muelleri, albacore Thunnus alalunga, bigeye tuna Thunnus obesus, yellowfin tuna Thunnus albacares, silver kob Argyrosomus inodorus, snoek Thyrsites atun, Cape hake Merluccius spp., kingklip Genypterus capensis and chokka squid Loligo vulgaris reynaudi. The purpose was to make use of all available sources of data to extend the spatial and temporal coverage of the southern Benguela. Six sources of data were combined on a 10′ × 10′ cell grid ...

Southern Iraq or lower Mesopotamia has a crucial role in Iraq’s economy due to its agricultural resources and unique wetland areas. Today southern Iraq, which is historically considered the birthplace of the development of early farming communities and the domestication of plants, is experiencing a drastic water resources crisis which is driven by both natural and human-induced reasons such as climate change, long periodical drought and water resources mismanagement practices. Despite the severity of the crisis, there is a lack of integrated and comprehensive assessments addressing the current state of water resources in southern Iraq. This paper aims to fill this gap by providing an in-depth review of the factors affecting water resources in the region. The current situation of water resources is analyzed using different indicators such as water availability in marshes, salinity variation along Shatt al-Arab river and surface of cultivated areas. This paper reviews previous studies, summarizes the current situation, analyzes the key challenges, and explores a range of potential solutions for further investigation. This study analysis is essential for guiding advanced research efforts that offer deeper insight into the challenges and propose practical solutions. This paper identifies key topics for future research to address the water crisis.

In Lebanon, the seasonal snowpack is poorly monitored despite its importance for water resource supply. The snow accumulates on Mount Lebanon in karstic depressions named “sinkholes.” It is important to monitor the evolution of the snow height inside those “sinkholes”, because of their key role as “containers” for seasonal snow. UAV photogrammetry is a major technological breakthrough which allows an accurate monitoring of the snow height. Because the impact of flight parameters on snow height retrievals is not well documented yet, this research aims to evaluate the impact of UAV flight altitude on the resolution and accuracy of the resulting orthomosaic and DSM. The flight missions were done using the Phantom DJI which generated five DSMs. These are validated using total station measurements.The results indicate that the snow DSMs can be retrieved by adopting a resolution of 8 to 84 cm, a point density between 1.43 and 153 points/sqm and a RMSE of 13 to 41 cm. The testing was done using an elevation varying between 50 and 500 m. The results will be compared to total station observations. These results allow the user to choose the suitable flight altitude for required resolution and points density. We suggest that a flight altitude of 100 m is sufficient for the survey of the snow cover elevation.

The SudMed project aims since 2002 at modelling the hydrological cycle in the Tensift semi arid watershed located in central Morocco. To reach these modelling objectives, emphasis is put on the use of high and low resolution remote sensing data, in the visible, near infrared, thermal, and microwave domains, to initialize, to force or to control the implementation of the process models. Fundamental studies have been conducted on Soil-Vegetation-Atmosphere Transfer modelling (SVAT), especially related to the various means of incorporating both ground and remote sensing observation into them. Satellite data have been used for monitoring the snow dynamic which is a major contribution to runoff issued from the mountains. Remote sensing image time series have also been used to map the land cover, based on NDVI time profiles analysis or temporal unmixing of low resolution pixels. Subsequently, remote sensing time series proved to be very valuable for monitoring the development of vegetation and the crop water status, in order to estimate of evapotranspiration, key information for irrigation management.

Résumé Il a été récemment montré que des modèles dynamiques pouvaient être directement obtenus du signal d'agriculture pluvial observé depuis l'espace. L'analyse de ce modèle a permis de révéler un régime chaotique, c'est-à-dire à la fois déterministe et très sensible aux conditions initiales. De tels modèles ne nécessitent pas de forçage et peuvent donc être envisagés en mode prévisionnel. En contexte chaotique, une telle application nécessite le développement de méthodes adaptées afin d'ajuster au cours de l'intégration les états visités par le modèle, en cohérence avec les observations. Dans ce but, plusieurs schémas d'assimilation ont donc été développés : (a) une simple réinitialisation, (b) un filtre de Kalman étendu, (c) un filtre de Kalman d'ensemble et (d) un nudging direct et rétrograde. La prévisibilité effective a été estimée pour chacune de ces approches en se basant sur la croissance d'erreur en fonction de l'horizon de prévision. Les résultats mettent en évidence une bonne capacité prédictive du modèle lorsqu'utilisé avec les schémas d'assimilation de données les plus sophistiqués et contribue à valider le modèle.