A technical reference for the satellite and gridded data sources commonly used in remote-sensing research — resolution, revisit time, temporal coverage, and the original documentation for each, drawn from public satellite-data archives.
The longest continuous, consistent optical satellite record available, making it the primary source for multi-decade trend analysis and long-baseline change detection.
Finer spatial detail and more frequent revisit than Landsat, at the cost of a shorter historical record — well suited to recent, fine-grained analysis.
Climate Hazards Group InfraRed Precipitation with Station data — blends satellite-derived rainfall estimates with ground station data for improved accuracy over data-sparse regions.
Shuttle Radar Topography Mission — near-global elevation data from a single 11-day shuttle mission, still the most widely used free global DEM.
Modeled population density (people per pixel), derived from census data disaggregated using satellite-derived settlement layers — used for population-weighted zonal statistics.
Radiance from artificial lighting at night — commonly used as a proxy for urbanization intensity, economic activity, and electrification.
C-band synthetic aperture radar. Because radar penetrates cloud and works day or night, Sentinel-1 is the go-to source for flood extent mapping during monsoon and storm events, when optical sensors are blinded by cloud cover. Backscatter (VV/VH) also responds to surface roughness and soil moisture.
The TROPOspheric Monitoring Instrument measures trace-gas column densities — nitrogen dioxide (NO₂), carbon monoxide (CO), sulphur dioxide, ozone, and more — making it the standard free source for mapping air-quality patterns over cities and industrial regions.
A Landsat-derived record of where surface water has been present over nearly four decades — water occurrence, seasonality, and change. Useful for flood-vulnerability context, reservoir and lake monitoring, and separating permanent from seasonal water bodies.