Low earth orbit nanosatellite: influence of heat dissipation on passive thermal analysis

The use of small satellites in ambitious missions presents challenges related to thermal breakdowns as one of the critical issues contributing to their failure. Heat dissipation and thermal management are still the major challenges in nanosatellite systems design. To meet the thermal stability requirements, it becomes statutory to manage passive and active thermal control to reach this goal while a variety of factors, such as high-powered components, sunlight and shadow on orbit, or a tight spacecraft layout, remain imposed.A spherical nanosatellite thermal analysis was performed to show the effect of energy dissipation in a low earth orbit and the stability of the system with a special attention to batteries, which persist as the weak link among electronics parts. Additionally, a set of different material coatings was used to demonstrate their impact on the nanosatellite’s thermal behaviour, hence highlighting their importance while designing such a spacecraft

Rainfall distribution and trends of the daily precipitation concentration index in northern Morocco: a need for an adaptive environmental policy

A national priority at the Moroccan level is to understand the spatiotemporal rainfall irregularity to anticipate suitable strategies for water and agriculture management. The most northern mountainous region shows intense sensitivity to extreme hydroclimatic hazards which may compromise the future of socioeconomic acceleration and further weaken environmental balances. However, planning and decision making require accurate data, on a detailed scale and with good spatial distribution which is not the case in several south-Mediterranean countries where rainfall data and/or well- established hydro-meteorological network is lacking. In this paper, abundant rain gauge measurements combined with time-series open data (1958-2015) were used to study the rainfall variability. Results show an annual rainfall increase trend since 1996 with frequent, intense and abundant rains causing violent torrents and floods. This humid trend alter- nates with short but severe dry periods. Spatial distribution shows a rainfall increase from eastern to western area and from the coastal plains to high mountains. Based on a continuous daily rainfall dataset (from 1988 to 2012) from six scat- tered stations, it appears that the pattern of heavy and extreme wet days takes the form of an irregular interannual cycle. Trends of the annual precipitation daily concentration indicate a significant positive trend in the center than in the East of the study area. Considering these observations, a review of water needs/obligations priorities seems crucial so that a new conscious and adaptative environmental policy would approve new procedures for a sustainable management

Review of wheat yield estimating methods in Morocco

Context and background:Wheat is one of the oldest crops in the world and has always been one of the most important staple foods for millions of people around the world, especially in North Africa, where wheat is the most dominant crop. The importance of wheat yield estimation is well known in agricultural management and policy making at regional and national levels.In semi-arid areas such as the case of Morocco, an operational cereal yieldestimating system that could assist decision makers in planning annual imports is needed.In some developed countries, several effective tools are now available to monitor crops and optimize farm-level decisions by combining crop simulation models with seasonal forecasts. However, few tools are used to effectively manage crops at the farm level to cope with climate variability and risk.Goal and objectives:The following article presents an overview of current methods used for wheat yield estimation in the world and in MoroccoMethodology:Various sections describing traditional methods, simulation models, and remote sensing. Then a section is devoted to the estimation methods used in Morocco and their efficiencies.Results:This article is very useful for researchers working on this subject because it brings together all the methods of estimating wheat yields worldwide and classifies them into categories and then situates Morocco, which is a relevant example of a North African country that is a leader in the use of spatial techniques and in the monitoring of crops, and wheat in particula

Impacts and social implications of landuse-environment conflicts in a typical Mediterranean watershed

In coastal watersheds, services and landuse favour coastal tourism and urbanization, depriving rural upstream of infrastructure and attention. This unbalanced management leads to an intensification of socioeconomic changes that generate a structural heterogeneity of the landscape and a reduction in the livelihoods of the rural population. The incessant dissociation between the objectives of the stakeholders triggers landuse-environment-economy conflicts which threaten to mutate large-scale development programs. Here, we used multi-assessment techniques in a Mediterranean watershed from Morocco to evaluate the effects of landuse change on water, vegetation, and perception of the rural population towards environmental issues. We combined complementary vegetation indexes (NDVI and EVI) to study long-term landuse change and phenological statistical pixel-based trends. We assessed the exposure of rural households to the risk of groundwater pollution through a water analysis supplemented by the calculation of an Integrated Water Quality Index. Later, we contrasted the findings with the results of a social survey with a representative sample of 401 households from 7 villages. We found that rapid coastal linear urbanization has resulted in a 12-fold increase in construction over the past 35 years, to the detriment of natural spaces and the lack of equipment and means in rural areas upstream. We show that the worst water qualities are linked to the negative impact of anthropogenic activities on immediately accessible water points. We observe that rural households are aware of the existence and gravity of environmental issues but act confusedly because of their low education level which generates a weak capacity to understand cause and effect relationships. We anticipate the pressing need to improve the well-being and education of the population and synergistically correct management plans to target the watershed as a consolidated system. Broadly, stakeholders should restore lost territorial harmony and reallocate landuse according to a sustainable environment-socioeconomic vision

Towards The Integration of Computer Simulators in The Teaching of Physical Sciences in Drc: Case of Ista / Kinshasa

In this work, we studied the possibility of improving the quality of teaching-learning of physical sciences (electricity and mechanics) that take place at ISTA/Kinshasa through the integration of computer simulators. For this, we based ourselves on the initial results of the research questionnaire that we distributed to all teachers of this subject in our host institution. We sought to understand their opinions on how the teaching-learning process of physical sciences is carried out in their institute. The analysis of the results of this questionnaire showed that the major problem that hinders the quality of the teaching-learning process of electricity and mechanics is the complexity of carrying out practical work with regard to the different physical phenomena. Moreover, this analysis has shown that it is possible to improve the quality of teaching-learning of electricity and mechanics at ISTA/Kinshasa by using computer simulators. This palliative solution to the absence of practical work in the teaching of physical sciences would compensate for the lack of equipment necessary for this training

Overview of soil organic carbon mapping using machine learning algorithms in Africa

This review provides an overview of the application of machine learning (ML) for Soil Organic Carbon (SOC) and Soil Organic Matter (SOM) mapping in African countries, highlighting its significance for agricultural productivity and environmental sustainability. In this review, studies conducted using geostatistical approaches without the use of ML algorithms, and those focusing on SOC stocks, were not considered. We identified 20 studies, with a notable emphasis on local research, including 5 studies in Morocco, 4 at the national scale, and 3 across the African continent. Random Forest (RF) model was the most frequently used and effective. Key predictors included spectral bands and vegetation indices, primarily derived from Landsat, elevation, and climatic variables from global or national databases. Despite promising results, challenges such as limited data availability and resistance to new methodologies persist. Opportunities for future research include focusing on small field studies, utilizing high-resolution remote sensing data, and exploring advanced ML techniques. This review aims to guide future research, foster collaboration, and optimize ML applications in SOC and SOM mapping for the advancement of African agriculture and sustainability

MODELING WHEAT YIELD BY USING PHENOLOGYCAL METRICS DERIVED FROM SENTINEL2 IN ARID AND SEMI-ARID REGIONS- A case study in MOROCCO-

ABSTRACT  Context and background Wheat is one of the oldest cultivated plants in the world and has always been one of the most important staples for millions of people around the world and especially in North Africa, where wheat is the most used crop for typical food industry. Thus, an operational crop production system is needed to help decision makers make early estimates of potential food availability Yield estimation using remote sensing data has been widely studied, but such information is generally scarce in arid and semi-arid regions such as North Africa, where interannual variations in climatic factors, and spatial variability in particular, are major risks to food security.Goal and Objectives: The aim of this study is to develop a model to estimate wheat yield based on phenological metrics derived from SENTINEL-2 NDVI images in order to generalize a spatial model to estimate wheat yields in Morocco's semi-arid conditionsMethodology:The 10 m NDVI time series was integrated into TIMESAT software to extract wheat phenology-related metrics during the 2018-2019 agricultural season, the period in which ground truth data was collected.  Through the multiple stepwise regression method, all phenological metrics were used to predict wheat yield. Moreover, the accuracy and stability of produced models were evaluated using a K-fold cross-validation (K-fold CV) method.Results:The results of the obtained models indicated a good linear correlation between predicted yield and field observations (R2 = 0.75 and RMSE of 7.08q/ha). The obtained method could be a good tool for decision makers to orient their actions under different climatic conditions

Application de la télédétection optique et RADAR pour contribuer à une gestion hydrique efficiente de la céréaliculture des périmètres irrigués au Maroc : Cas du périmètre irrigué du Tadla.

« l’Application de la télédétection optique et radar pour contribuer à la gestion de la céréaliculture dans les périmètres irrigués : cas du périmètre irrigué de Tadla ». Cette présentation est un résumé de projet de thèse doctorale qui vise à contribuer à une gestion synoptique du périmètre irrigué grâce aux outils de la télédétection spatiale optique et radar combinés à la modélisation agrométéorologique

Recours aux satellites pour appuyer le management de l’eau d’irrigation: Estimation des besoins en eau des agrumes par télédétection dans la Plaine de Triffa-Berkane (Maroc)

Les agrumes représentent la première culture irriguée dans la plaine de Trifa (Berkane, Maroc) avec une superficie en extension continue. Ceci accentue les pressions sur les ressources en eau déjà limitées dans la région. De ce fait, une gouvernance efficace et rationnelle de l’eau agricole s’impose. Dans ce travail, nous proposons une approche basée sur les observations satellitaires pour appuyer la gestion de l’eau d’irrigation consommée par les surfaces agrumicoles. Cette approche est scindée en deux étapes : des cartes de coefficient cultural d’agrumes ont été d’abord établies à partir d’une cartographie d’agrumes stratifiés selon l’âge, dérivée à partir des images satellitaires Sentinel optique et radar. Ensuite, une implémentation validée du modèle de Hargreaves a permis l’estimation de l’évapotranspiration potentielle à partir des images thermiques du capteur TIRS du Landsat 8. Comparé au modèle de référence de Penman-Montheith, une erreur (RMSE) inférieure à 0.5mm/jour est enregistrée. Finalement, le croisement des cartes du coefficient cultural et de l’évapotranspiration potentielle a permis de spatialiser l’évapotranspiration maximale des agrumes à l’échelle du pixel de la taille d’un hectare. Ces informations pourraient être intelligemment converties en services de pilotage assisté de l’irrigation pour une meilleure productivité de l’eau agricole