Satellite Remote Sensing of Surface Water Dynamics

Satellite remote sensing has transformed the monitoring of surface water by providing consistent, synoptic observations of lakes, reservoirs, rivers and wetlands at regional to global scales. Combining passive optical imagery (for example Landsat and Sentinel-2) with active altimetric measurements (radar and laser) enables the simultaneous determination of water extent, surface elevation and volumetric storage changes. These data inform assessments of hydrological variability, water security and the impacts of climate change and human activities on freshwater resources. Methodological advances in hypsometric modelling, time-series analysis and multi-mission cross-calibration have improved accuracy and extended temporal coverage. Emerging applications include near-real-time flood forecasting, reservoir management under shifting demand and the integration of surface water dynamics into coupled climate–hydrology models. Despite challenges such as spatial resolution limits, data continuity and terrain complexity, the synergy of diverse satellite platforms underpins a new era of comprehensive, cost-effective surface water monitoring with profound implications for global water governance and ecosystem management.

Research from Nature Portfolio

Recent studies have used satellite observations to quantify global reservoir storage trends over the past two decades. Multi-mission altimetry from Topex/Poseidon and the Jason series, together with optical imagery, reveals that total reservoir storage rose by approximately 27.8 km³ per year between 1999 and 2018, driven primarily by new dam construction. However, the normalised storage index—the ratio of actual storage to capacity—declined by about 0.82 % per annum, with the most pronounced decreases occurring in the global south. This divergence between capacity expansion and storage efficiency underscores mounting pressures on water availability in regions facing declining runoff and growing demand, highlighting the necessity of integrating satellite-derived metrics into future water resource planning.

Satellite Remote Sensing of Surface Water Dynamics publication trend

The graph below shows the total number of articles in satellite remote sensing of surface water dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Altimetry: Measurement of water surface elevation using radar or laser pulses emitted and received by a satellite.

Optical remote sensing: Acquisition of surface water extent by detecting reflected solar radiation in multiple spectral bands.

Radar altimetry: Active microwave sensing technique that estimates surface height from the travel time of radar echoes.

Hypsometry: Relationship between water surface elevation and horizontal area used to convert level changes into volume changes.

Normalised storage index (NS): Ratio of actual reservoir storage to its maximum capacity, indicating storage efficiency.

Surface water extent: Spatial footprint of water bodies derived from satellite image classification.

References

1. Diminishing storage returns of reservoir construction. Nature Communications (2023).
2. GloLakes: water storage dynamics for 27 000 lakes globally from 1984 to present derived from satellite altimetry and optical imaging. Earth System Science Data (2024).
3. A global lake and reservoir volume analysis using a surface water dataset and satellite altimetry. Hydrology and Earth System Sciences (2019).
4. DAHITI – an innovative approach for estimating water level time series over inland waters using multi-mission satellite altimetry. Hydrology and Earth System Sciences (2015).
5. Multi-Mission Cross-Calibration of Satellite Altimeters: Constructing a Long-Term Data Record for Global and Regional Sea Level Change Studies. Remote Sensing (2014).