High-resolution precipitation datasets in South America and West Africa based on satellite-derived rainfall, Enhanced Vegetation Index and Digital Elevation Model

Mean Annual Precipitation is one of the most important variables used in water resource management. However, quantifying Mean Annual Precipitation at high spatial resolution, needed for advanced hydrological analysis, is challenging in developing countries which often present a sparse gauge network and a highly variable climate. In this work, we present a methodology to quantify Mean Annual Precipitation at 1 km spatial resolution using different precipitation products from satellite estimates and gauge observations at coarse spatial resolution (i.e., ranging from 4 km to 25 km). Examples of this methodology are given for South America and West Africa. We develop a downscaling method that exploits the relationship among satellite-derived rainfall, Digital Elevation Model and Enhanced Vegetation Index. At last, we validate its performance using rain gauge measurements: comparable annual precipitation estimates for both South America and West Africa are retrieved. Validation indicates that high resolution Mean Annual Precipitation downscaled from CHIRP (Climate Hazards Group Infrared Precipitation) and GPCC (Global Precipitation Climatology Centre) datasets present the best ensemble of performance statistics for both South America and West Africa. Results also highlight the potential of the presented technique to downscale satellite-derived rainfall worldwide.JRC.H.1-Water Resource

2018 - Drought and Water Crisis in Southern Africa

The results presented in this short technical report are focused on the 2018 Water Crisis that affected the Western Cape Province in South Africa. In one side it includes an analysis carried out by the JRC´s "Disaster Risk Management" Unit and the Global Drought Observatory (GDO report), which periodically provides an overview of precipitation patterns and its anomalies, including also those related to vegetation greenness and soil moisture values respect to the long term average. In the other, it presents a complementary section carried out by the WEFE4DEV Work Package of the Water-Energy-Food-Ecosystems (WEFE) Project which contributes to the online African Atlas on WEFE Cooperation. The analysis is focused on the medium to long term spatio-temporal patterns and behaviour of precipitation and temperature patterns. Both help the community to better understand the exceptional character of these phonomena, their periodicity and the scale at which these events occur. The outcomes are helpful for policymakers to identify current and future issues that impact water management, food and energy security in Africa, as well as they providevaluable information to better define mitigation measures, resilience and adaptation policies.JRC.D.2-Water and Marine Resource

Position Paper on Water, Energy, Food and Ecosystem (WEFE) Nexus and Sustainable development Goals (SDGs)

The EU and the international community is realising that the Water, Energy, Food and Ecosystem components are interlinked and require a joint planning in order to meet the daunting global challenges related to Water, Energy and Food security and maintaining the ecosystem health and in this way, reach the SDGs. If not dealt with, the world will not be able to meet the demand for water, energy and food in a not too far future and, in any case, in a not sustainable way. The strain on the ecosystems resulting from unsustainable single-sector planning will lead to increasing poverty, inequality and instability. The Nexus approach is fully aligned with and supportive of the EU Consensus on Development. Key elements of the Consensus will require collaborative efforts across sectors in ways that can be supported/implemented by a Nexus approach. In this way, transparent and accountable decision-making, involving the civil society is key and common to the European Consensus on Development and the Nexus approach. The Nexus approach will support the implementation of the SDG in particular SDG 2 (Food), SDG 6 (Water) and SDG 7 (Energy), but most SDGs have elements that link to food, water and energy in one or other way, and will benefit from a Nexus approach. The SDGs are designed to be cross-cutting and be implemented together, which is also reflected in a WEFE Nexus approach. A Nexus approach offers a sustainable way of addressing the effects of Climate Change and increase resilience. The WEFE Nexus has in it the main drivers of climate change (water, energy and food security) and the main affected sectors (water and the environment). Decisions around policy, infrastructure, … developed based on the WEFE Nexus assessments will be suitable as elements of climate change mitigation and adaptation. In fact, it is difficult to imagine solutions to the climate change issue that are not built on a form of Nexus approach. The Nexus approach is being implemented around the world, as examples in the literature demonstrate. These examples together with more examples from EU and member state development cooperation will help build experience that can be consolidated and become an important contribution to a Toolkit for WEFE Nexus Implementation. From the expert discussions, it appears that because of the novelty of the approach, a Toolkit will be an important element in getting the Nexus approach widely used. This should build on experiences from practical examples of NEXUS projects or similar inter-sectorial collaboration projects; and, there are already policy, regulation and practical experience to allow institutions and countries to start applying the Nexus concept.JRC.D.2-Water and Marine Resource

Heat waves in Africa 1981-2015, observations and reanalysis

The purpose of this article is to show the extreme temperature regime of heat waves across Africa over recent years (1981–2015). Heat waves have been quantified using the Heat Wave Magnitude Index daily (HWMId), which merges the duration and the intensity of extreme temperature events into a single numerical index. The HWMId enables a comparison between heat waves with different timing and location, and it has been applied to maximum and minimum temperature records. The time series used in this study have been derived from: 1) observations from the Global Summary of the Day (GSOD); and 2) reanalysis data from ERA-INTERIM. The analysis show an increasing number of heat waves of both maxima and minima temperatures in the last decades. Results from heat wave analysis of maximum temperature (HWMIdtx) indicate an increase in intensity and frequency of extreme events. Specifically, from 1996 onwards it is possible to observe HWMIdtx spread with the maximum presence during 2006-2015. Between 2006 and 2015 the frequency (spatial coverage) of extreme heat waves had increased to 24.5 observations per year (60.1% of land cover), as compared to 12.3 per year (37.3% of land area) in the period from 1981 to 2005 for GSOD stations (reanalysis).JRC.D.2-Water and Marine Resource

Assessing floods and droughts in the Mékrou River Basin (West Africa): A combined household survey and climatic trends analysis approach

The assessment of natural hazards such as floods and droughts is a complex issue that demands integrated approaches and high-quality data. Especially in African developing countries, where information is limited, the assessment of floods and droughts, though an overarching issue that influences economic and social development, is even more challenging. This paper presents an integrated approach to assessing crucial aspects of floods and droughts in the transboundary Mékrou River basin (a portion of the Niger River basin in West Africa), combining climatic trends analysis and the findings of a household survey. The multivariable trend analysis estimates, at the biophysical level, the climate variability and the occurrence of floods and droughts. These results are coupled with an analysis of household survey data that reveals the behaviour and opinions of local residents regarding the observed climate variability and occurrence of flood and drought events, household mitigation measures, and the impacts of floods and droughts. Based on survey data analysis, the paper provides a per-household cost estimation of floods and droughts that occurred over a 2-year period (2014–2015). Furthermore, two econometric models are set up to identify the factors that influence the costs of floods and droughts to impacted households.JRC.D.2-Water and Marine Resource