A recent study has highlighted how observing areas such as the Amazon basin from space demonstrates the effectiveness of satellites in identifying drought signs.
This research, led by the Military University of Technology in Poland and Griffith University, successfully merged two advanced satellite techniques to enhance the monitoring of hydrological droughts.
Technologies like the Global Positioning System (GPS) and the Gravity Recovery and Climate Experiment (GRACE) have proven essential for tracking variations in global freshwater reserves, including groundwater levels.
However, Dr. Christopher Ndehedehe, a co-author and an ARC DECRA Fellow at Griffith’s Australian Rivers Institute, pointed out some limitations of these methods.
“While GRACE offers dependable data on large and regional scales, it struggles at the local level. Meanwhile, GPS data can be influenced by technical issues and environmental conditions, such as monument instability and thermal expansion of the ground. Additionally, capturing actual changes in water systems can be quite challenging, along with other persistent issues,” Dr. Ndehedehe explained.
“Both methods encounter difficulties in tracking short-term extreme hydrological events like rapid droughts, leading to potential underestimations or overestimations of their occurrence and severity.”
To address these challenges, the research team devised a new strategy that utilizes the strengths of both GPS and GRACE vertical displacement data to monitor hydrological droughts more effectively.
This innovative method was validated in the Amazon basin and California’s Central Valley, where notable hydrological changes can provide vital insights for water management.
“By integrating GPS and GRACE data, our new drought indicator improves our capability to track short-term drought events more precisely, delivering timely and actionable insights for decision-makers,” Dr. Ndehedehe stated.
“Plans to adapt to the effects of climate change must blend careful management of water resources with the creation of appropriate indicators and metrics to evaluate drought impacts on freshwater systems.”
Though both GPS and GRACE methods independently aligned well with traditional drought indices (like the standardized precipitation index), they occasionally overlooked extreme events.
To overcome this gap, the research group introduced a new multivariate drought indicator (Multivariate Drought Severity Index) that combines GPS and GRACE datasets using advanced statistical techniques known as Frank copulas, which integrate data from the two satellite missions.
This methodology enabled the researchers to discover drought events that had previously gone undetected and the subsequent effects on freshwater systems.
Dr. Artur Lenczuk, an Assistant Professor and the lead author from the Military University of Technology in Poland, stated: “Droughts are intricate, and their consequences can be catastrophic, especially in areas with highly variable climates. Monitoring drought onset and development is crucial for managing water resources.”
“The multivariate drought indicator showed strong temporal alignment with drought indicators derived from in-situ river discharge data and satellite-based agricultural indices like the Enhanced Vegetation Index, further confirming its accuracy and offering a more well-rounded view of drought situations.”
This new approach provides a comprehensive understanding of drought conditions to facilitate improved resource management and signifies substantial progress in the quest for more effective drought monitoring, which is essential for global water management strategies.
As climate change accelerates, many regions worldwide are experiencing more frequent and intense droughts, significantly impacting ecosystems, communities, and water resources.
Monitoring these climate and water storage changes is vital for informed water management.
