OBSERVER: How the EU Space Programme helps us monitor drought around the world
OBSERVER: How the EU Space Programme helps us monitor drought around the world
evan
Wed, 22/01/2025 – 11:58
According to the World Drought Atlas, droughts directly affect up to 55 million people worldwide each year. Among the most costly and dangerous natural hazards, droughts affect access to drinking water, agriculture, energy, trade, and navigation. They also threaten ecosystems and the essential services they provide.
Because droughts are complex and their effects far-reaching, managing their impacts effectively calls for coordinated strategies. In this week’s Observer, we explore how, the EU Space Programme, with its extensive and accessible data, provides valuable support for monitoring droughts and mitigating their effects.
Monitoring drought from space with Copernicus
The EU Space Programme helps monitor droughts worldwide, with Copernicus being a prominent example.
The Copernicus Sentinel satellites provide valuable data for tracking droughts by using advanced instruments to capture high-resolution imagery and spectral data of vegetation, soil moisture, and water bodies on Earth’s surface. These observations are critical for monitoring key drought indicators such as vegetation health and extent, soil moisture, and surface water. For instance, the Sentinel-2 satellite mission uses a multispectral instrument (MSI) to gather detailed data about Earth’s surface through its 13 spectral bands. Band 8, operating in the near-infrared spectrum, is used to detect and analyse vegetation health and coverage, supporting the creation of indices like the Normalised Difference Vegetation Index (NDVI).
Thanks to their orbital configuration, Sentinel-2 satellites can revisit the same location every five days at the equator, with more frequent coverage at higher latitudes, providing consistent and reliable data on water levels. Meanwhile, other missions, such as Sentinel-1, use radar technology to monitor water bodies even at night or under cloudy skies.
Copernicus does not just contribute through its data—it also raises public awareness. The Copernicus Image of the Day, published daily since 2020, highlights the severe impacts of drought on ecosystems and communities.
For example, a Copernicus Image of the Day published in April 2024, featured Sentinel-2 images of the Cogotí reservoir in Chile, showing a sharp drop in water levels. The comparison between 2023 and 2024 illustrated the extent of the devastating drought in the region, which drastically affected water supplies for agriculture and mining.
Sentinel-2 imagery of the Cogotí Reservoir in Chile in 2023 and 2024. Credit: European Union.
Similarly, Sentinel-2 images from 2022 and 2023 documented water loss at the Chaillexon Lake, on the France-Switzerland border. The comparison vividly illustrates the severity of the drought. Copernicus Sentinel imagery makes the effects of drought more tangible and stresses the urgent need for global water management efforts.
Sentinel-2 imagery of the Chaillexon Lake on the France-Switzerland border. Credit: European Union.
Monitoring drought impacts and risks with the Copernicus services
The Copernicus Emergency Management Service (CEMS) plays an important role in understanding, monitoring, and predicting droughts. Drought monitoring requires analysis of the hydrological cycle, including precipitation and soil moisture, as well as drought-related impacts on vegetation. In this context, the CEMS drought component, which comprises the European Drought Observatory (EDO) and the Global Drought Observatory (GDO), provides near real-time data, forecasts, and early warnings.
The Observatories integrate satellite observations, hydro-meteorological models, and in situ measurements to provide drought indicators such as soil moisture, vegetation anomalies, and agricultural drought, with the Combined Drought Indicator (CDI) as one of its most valuable products.
Complementing this, the new European Drought Risk Atlas assesses the interactions between drought hazard, exposure, and vulnerability across various sectors such as agriculture, public water supply, and energy. It allows users to assess projected drought risks under different global warming scenarios (1.5 °C, 2 °C and 3 °C), providing essential insights for long-term planning across multiple sectors. Additionally, the European Drought Impact Database (EDID), now publicly available, contains over 13,000 georeferenced records of drought impacts across Europe since 1970. Both platforms support drought risk management and adaptation.
Analyses from the Copernicus Climate Change Service (C3S) also help paint a clear picture of how climate conditions and extremes affect communities worldwide. C3S provides high-quality climate data, monitoring long-term climate trends using key variables such as temperature and precipitation. This information can be used by policymakers to make informed decisions to reduce the impact of anomalous climate conditions and extremes on communities and ecosystems.
Building drought resilience with the World Drought Atlas
The launch of the World Drought Atlas at last year’s COP16 in Riyadh is an important step towards building global drought resilience. This joint publication by the European Commission’s Joint Research Centre and the United Nations Convention to Combat Desertification (UNCCD) provides an overview of current and emerging drought-related risks. By examining past, present, and future drought conditions, the Atlas underlines the effects of drought on economies, communities, and ecosystems, as well as highlighting the urgent need for coordinated action to address the increasing global threat of drought.
The World Drought Atlas provides practical insights and actionable guidance for policymakers to build drought resilience. It promotes a shift towards proactive and forward-looking strategies, highlighting the need to fill knowledge gaps, improve drought forecasting, and strengthen early warning systems.
The resources provided by CEMS to the Atlas highlight its role in delivering the important information needed by stakeholders to monitor and develop effective mitigation strategies for drought-related risks.
Examples of major drought events which occurred between 2022 and 2024. Red areas represent the approximate spatial extent of drought impacts. Credit: European Union, Joint Research Centre.
Using data from Galileo to monitor drought conditions
Galileo, Europe’s Global Navigation Satellite System (GNSS), plays a lesser-known role in supporting drought monitoring. At first glance, navigation might not seem relevant to tracking drought and water scarcity. However, scientists worldwide are exploring how navigation data can improve the accuracy of drought indices by providing information on surface conditions.
One such technique is GNSS Reflectometry (GNSS-R), a remote sensing technique that uses GNSS signals to analyse the Earth’s surface. GNSS-R works by capturing signals reflected from the Earth’s surface. When a GNSS signal, originally intended for navigation, strikes the ground, part of it bounces back into space. Receivers on the ground, in the air, or aboard satellites can collect and analyse this reflected signal. By cross correlating the reflected signal with either a locally generated replica or the directly received signal, researchers can produce maps which provide information about the reflecting surface, such as surface roughness, moisture content, and more. This data could then be delivered to land managers and farmers, enabling them to make informed decisions about water use and improve resource management on their land.
Sentinel-2 imagery of a prolonged drought in Morocco in 2024, which is causing serious problems for the agricultural sector. In the future, GNSS-R data could be provided to land managers and farmers, helping them make informed decisions about water use and improve resource management on their land. Credit: European Union.
Droughts pose a significant threat to communities, ecosystems, and economies worldwide. The EU Space Programme is helping to address this challenge by delivering invaluable data and services for monitoring and understanding drought. Copernicus provides the data needed to track changes in water availability, soil moisture, and vegetation health, while innovative use of GNSS data from Galileo offers new opportunities to improve drought assessments. Together, these capabilities support informed decision-making and help build resilience against one of the most pressing environmental challenges of our time.
Wed, 22/01/2025 – 12:00
