Slapis Sahel Archives - climateservices.it CNR-IBE

From training to transformation: co-producing sustainable early warning competence in West Africa

Vieri Tarchiani — Mon, 13 Apr 2026 09:51:45 +0000

Operational numerical weather prediction in Sub-Saharan Africa remains fragile despite increasing availability of models and data. A key limiting factor is the limited operational and institutional capacity of National Meteorological Services to operate, assess, adapt, and sustain forecasting chains within routine operations for early warning systems. Short-term, tool-oriented training initiatives often fail to address this gap, as learning remains weakly embedded in daily service delivery and rarely translates into sustained operational competence.

This paper presents a qualitative case study examining how co-production principles can be operationalized to support the development of operational competence for flood early warning. The study draws on a long-term capacity-development experience involving the National Meteorological Services of Niger and Burkina Faso and the Tuscany Regional Meteorological Service in Italy. The approach combined long-term embedding of trainees within an operational forecasting team, training-of-trainers, and peer-to-peer institutional collaboration, linking learning to real operational workflows.

Results are analysed across methodological, operational, and institutional dimensions. Methodological findings show how co-production principles can structure competence-oriented training processes by integrating instructional design, operational practice, and iterative evaluation. Operational results highlight the importance of sustained practice and routine verification, while institutional results point to the role of training of trainers and public institutional collaboration supporting sustainability of competence beyond individual skills and knowledge.

By reframing competence as a foundational component of climate services, the study offers transferable insights for capacity development in resource-constrained and transboundary contexts.

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DEM Generation from Multi-View Satellite Images in Sub-Sahel Region

Web Editor — Fri, 13 Jun 2025 07:37:12 +0000

Floods are causing a significant loss of human lives and valuable resources in West Africa. In particular, Niger and Burkina Faso were highly affected areas in past years. In order to predict flood, an accurate Digital elevation model (DEM) is required for flood mapping. At the studied area in Niger, up to this date, the LiDAR DEMs are scarcely available, and the only available DEMs are global DEMs like global SRTM DEMs with a resolution of 10m. These global DEMs are not accurate enough to be used for flood mapping. So, in this context, this study investigates the potential of multidate, multi-view stereo pairs PlanetScope images for the generation of DEM. Three DEMs were generated from images with slightly different view angles to see the effect of view angles of images on 3D modelling. One of the DEM generated by PlanetScope images was compared with DEM generated by high-resolution drone imagery and shows the normalized Median of Absolute Deviation (NMAD) of the elevation differences of 10m. Results show that planetScope images are useful assets for generating multiple DEMs due to their high temporal resolution. Such DEMs could be extremely useful for studying dynamic phenomena or monitoring disaster events like floods.

Keywords: Remote Sensing, DEM Generation, Cubesat Satellites, Stereo-Modelling, 3D Modelling

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Flood risk assessment of agricultural areas along the Niger river upstream Niamey

Web Editor — Wed, 30 Apr 2025 13:24:37 +0000

Much of the food supplied to the city of Niamey (1.5 million inhabitants), the capital of Niger, comes from 150 large commercial horticultural sites and 10 vast irrigated perimeters distributed along the Niger River upstream of the city. These areas are threatened by floods, such as the one that devastated paddy fields and horticultural areas in August 2024. To address this problem, a detailed assessment of the river flood risk, expressed in monetary terms, is urgently needed to complement the early flood warning system.

This activity is part of the SLAPIS Sahel project, which aims to develop a more general framework for flood risk management applied to the transboundary Sirba river basin and the nearby Niger river, with the active participation of the water authorities of Burkina Faso and Niger. In this context, this work focuses on the flood risk analysis of the Niger River upstream of the city of Niamey in a multidisciplinary way. To this aim, a hydrological study of the basin was carried out, taking into account the two types of floods that affect the area: floods due to the local rainy season, and dry season events caused by floods upstream in the Guinea-Conakry basin. A hydraulic model was then used to map the extent of flooding, allowing to study the impact and expected damage to the target areas. Daily satellite imagery was used to assess the extent of recent floods and the characteristics of the exposed areas. All these activities were repeated for both the wet and dry seasons, as agricultural production changes and the impacts are different.

This analysis supports the cost-benefit assessment of possible defense structures.

Link to EGU presentation EGU25_PICO_SLAPIS

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Flood Damage Risk Mapping Along the River Niger: Ten Benefits of a Participated Approach

Web Editor — Wed, 30 Apr 2025 13:17:14 +0000

Flood risk mapping is spreading in the Global South due to the availability of high-resolution/high-frequency satellite imagery, volunteered geographic information, and hydraulic models. However, these maps are increasingly generated without the participation of exposed communities, contrary to the Sendai Framework for Disaster Risk Reduction 2015–2030 priorities. As a result, the understanding of risk is limited. This study aims to map flood risk with citizen science complemented by hydrology, geomatics, and spatial planning. The Niger River floods of 2024–2025 on a 113 km2 area upstream of Niamey are investigated. The novelty of the work is the integration of local and technical knowledge in the micro-mapping of risk in a large area. We consider risk the product of a hazard and damage in monetary terms. Focus groups in flooded municipalities, interviews with irrigation perimeter managers, and statistical river flow and rainfall analysis identified the hazard. The flood plain was extracted from Sentinel-2 images using MNDWI and validated with ground control points. Six classes of assets were identified by visual photo interpretation of very high-resolution satellite imagery. Damage was ascertained through interviews with a sample of farmers. The floods of 2024–2025 may occur again in the next 12–19 years. Farmers cannot crop safer sites, raising significant environmental justice issues. Damage depends on the strength of the levees, the crop, and the season. From January to February, horticulture is at a higher risk. Flooding does not bring benefits. Risk maps highlight hot spots, are validated, and can be linked to observed flood levels.

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Compound-event analysis in non-stationary hydrological hazards: a case study of the Niger River in Niamey

Web Editor — Thu, 05 Dec 2024 12:49:56 +0000

This study examines compound hydrological hazards in a non-stationary context, specifically focusing on the Niger River in Niamey. The hazard results from the confluence of local Sahelian and more remote Guinean tributaries, displaying seasonal floods. The study first investigates whether Niamey’s annual flood hazard is a compound result of Sahelian and Guinean flows, and then assesses the value of a compound hazard approach versus traditional flood analyses in this region. Analyzing discharge data from 1950 to 2020, the study disentangles Sahelian and Guinean flow impacts. It compares flood return level estimations from three statistical models of varying complexity. Findings confirm Niamey’s hazard as compound, stressing the need to consider both tributaries separately. Incorporating non-stationarity in statistical modeling is crucial, yet fully integrating the compound nature of hazards doesn’t significantly change the quantitative estimation of the hazard in Niamey.

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Geospatial Capacity Building for Flood Resilience in the Sahel: the SLAPIS project case study

Web Editor — Thu, 05 Dec 2024 12:47:45 +0000

This study focuses on the development of a people-centred early warning system (EWS) against floods in the Sirba River basin between Niger and Burkina Faso. This densely populated area has witnessed an increase in extreme flooding events in recent years. Several flood forecasting systems in the Sahel exist, although there is no EWS that integrates the four components of people-centred EWSs, namely risk knowledge, monitoring and warning service, dissemination and communication, and response capacity. The proposed EWS, named SLAPIS, includes a risk knowledge component that involves defining four levels of vigilance. Its monitoring and alert component involves a user-friendly web application containing real-time data collected through automatic stations. The EWS communicate seamlessly with the national alert system. The response capacity is strengthened through the creation of a flood zone atlas. In this framework, the EWS integrates significant geoinformatics in preparation of local risk reduction plans and the awareness of local communities. In the SLAPIS case study, multi-temporal classifications were conducted using Sentinel-2 data and high-resolution images (approximately 10 cm) generated through Structure from Motion (SfM) techniques. Digital Terrain Model (DTM) creation for hydraulic model calibration employed a multiscale approach, incorporating GNSS survey data processed via Precise Point Positioning (PPP), HydroSHEDS (approximately 100m resolution), and commercial 10m resolution data. All information was calibrated, harmonised, and integrated into the EWS model, which is accessible via a web platform. Capacity building encompassed direct training and field implementation to streamline the primary EWS generation steps.

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Comparative Trend Analysis of Precipitation Indices in Several Towns of the Sirba River Catchment (Burkina Faso) from CHIRPS and TAMSAT Rainfall Estimates

Web Editor — Thu, 05 Dec 2024 12:44:42 +0000

The increasingly frequent pluvial flood of West African urban settlements indicates the need to investigate the drivers of local rainfall changes. However, meteorological stations are few, unevenly distributed, and work irregularly. Daily satellite rainfall datasets can be used. Nevertheless, these products often need to be more accurate due to sensor errors and limitations in retrieval algorithms. The problem is, therefore, how to characterize rainfall where there is a need for ground-based rainfall records or incomplete series. This study aims to characterize urban rainfall using two satellite datasets. The analysis was carried out in the Sirba river catchment, Burkina Faso, using the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) and the Tropical Applications of Meteorology using SATellite and ground-based data (TAMSAT) datasets. Ten indices from the Expert Team on Climate Change Detection and Indices (ETCCDI) of precipitation were calculated, and their statistical trends were evaluated from 1983 to 2023. The study introduces two key innovations: a comparative analysis of precipitation trends using two satellite datasets and applying this analysis to towns within a previously understudied 39,138 km2 catchment area that is frequently flooded. Both datasets agree on the increase of (i) annual cumulative rainfall over all towns, (ii) five-day maximum rainfall over the town of Manni, (iii) rainfall due to very wet days in Gayéri, (iv) days of heavy rainfall in Bogandé, Manni and Yalgho, and (v) days of very heavy rainfall in Yalgho. These findings suggest the need for targeted pluvial flood prevention measures in towns with increasing trends in heavy rainfall.

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