Flood extent from radar
Synthetic-aperture radar sees through cloud. Change detection between a dry reference and the event image maps open water at ten metres, within hours of acquisition.
The Global Centre for Risk and Innovation (GCRI)
Satellites see the whole basin at once and return every few days: surface water, soil moisture, snow, vegetation stress and, after an event, the extent of the flood. Earth observation fills the gaps that thinning gauge networks leave.
Water NexusWireframe of the working environment, not a live screen. Names and values are placeholders.
Earth observation and remote sensing gather information about the Earth’s surface and atmosphere from airborne and spaceborne sensors. They provide consistent, repeatable measurements over areas that are hard to monitor on the ground. In water, climate and hazards and critical infrastructure, earth observation maps exposure, damage and environmental change across borders and sectors. It supports rapid assessment after disasters and long-term monitoring of risk drivers. The canonical description is on the STEM Commons.
Synthetic-aperture radar sees through cloud. Change detection between a dry reference and the event image maps open water at ten metres, within hours of acquisition.
Optical time series track reservoir area and seasonal wetlands over decades, giving a storage proxy where operators do not publish levels.
Vegetation indices, land-surface temperature and radiometer soil moisture are combined into drought indicators that agree, or disagree, with rainfall indices.
Where this page’s subject sits in the world: boundaries and context now, the field layers when the interactive map loads.
MapWorld map in the Equal Earth projection, land and boundaries from Natural Earth (public domain). The interactive map loads through the Nexus Foundry plugin (globe or flat view).
Data from the source register feeds the methods; calibration and an independent test gate the estimate and its limits; the decision stays with the competent authority.
Fig. 01Nodes carry their type, metrics and state; connectors show what feeds what; the gates are the validation steps; the timeline is one application. Design of the method’s use, not a record of a run.
Datasets and records used by earth observation and remote sensing on this platform, with the role each plays and the label its values carry. Sources are listed in the source register.
| Data | Role | Label |
|---|---|---|
| Sentinel-1 radar | Flood extent, soil moisture | OBSERVED |
| Sentinel-2 and Landsat optical | Surface water, vegetation stress | OBSERVED |
| SMAP and SMOS radiometers | Soil moisture | MODELLED |
| GRACE-FO gravimetry | Terrestrial water storage anomaly | MODELLED |
| MODIS and VIIRS | Snow cover, land-surface temperature | OBSERVED |
Products are assessed against ground reference data using accuracy matrices and independent samples. Cross-calibration between sensors checks consistency over time.
| Check | How it is done |
|---|---|
| Ground reference | Flood masks are scored against surveyed high-water marks and gauge-derived extents |
| Cross-sensor consistency | Products from different satellites are compared over the same period before a trend is quoted |
| Cloud and revisit gaps | Every product states its coverage; missing scenes are reported as no data, not as no change |
Clouds, revisit gaps and mixed pixels limit what can be observed. Changes in sensors and processing can create artificial trends.
Space and Earth Observation stewards earth observation and remote sensing for the Consortium and reviews how it is applied across platforms.
| Link | Relationship | Why |
|---|---|---|
| Earth observation and remote sensing | Canonical method page | Platform application links to the canonical method page. |
| Earth observation and remote sensing in space and earth observation | Steward platform | Space and Earth Observation stewards this method. |
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.