(Approx. 30 min reading incl. references)
Multisource remote sensing has become an essential approach for understanding and managing agricultural systems. By combining information from different sensors, platforms, and spatial or temporal resolutions, it provides a more complete view of crop conditions, management practices, and environmental influences over large areas. Optical data offer detailed information on vegetation greenness and canopy structure, while radar observations provide insights into soil moisture and crop development regardless of cloud cover. Thermal sensors add valuable information on plant water status and surface energy fluxes. Together, these complementary data streams enable more accurate monitoring of crop growth, detection of stress, and assessment of productivity across diverse agricultural landscapes. Satellite earth observation data such as Sentinel, Landsat, and MODIS provide complementary data for agricultural monitoring.
High-to-moderate-resolution missions like Sentinel-1 and Sentinel-2 offer detailed spatial information on crop structure and vegetation dynamics. Sentinel-1 radar observations are well suited for monitoring soil moisture and structural changes in crops under all weather conditions. The Copernicus Sentinel-1 mission is designed as a two-satellite constellation, capable of imaging the Earth every 6 days. The original satellites, Sentinel-1A and Sentinel-1B, have been succeeded by Sentinel-1C and Sentinel-1D, launched in recent years and ensuring the continuation of the mission. Each satellite carries a C-band Synthetic Aperture Radar sensor, providing consistent, high-quality data for agricultural applications.
Multispectral optical missions with global coverage and moderate spatial resolution include Sentinel-2, Landsat and MODIS, providing information on vegetation dynamics. These multispectral imaging systems capture narrow spectral bands (like blue, green, red, NIR, SWIR1, SWIR2). For instance, Sentinel-2 imagery provides rich spectral information for assessing vegetation status and management practices. The satellite pair Sentinel-2A and Sentinel-2B capture 13 spectral bands and revisit the same location every 5 days.
The Landsat program delivers moderate-resolution optical data with a long historical archive, making it particularly valuable for analyzing long-term changes in agricultural systems. Since the launch of Landsat-1 in 1975, nine multispectral satellites have been deployed, making exceptionally long time series possible. The most recent missions, Landsat-8 and Landsat-9, provide global coverage every eight days combined. Easy access to Landsat data and historical archives is provided through NASA’s Earth Data Search (https://search.earthdata.nasa.gov) or the USGS’s Earth Explorer (https://earthexplorer.usgs.gov/). MODIS (Moderate Resolution Imaging Spectroradiometer) offers high temporal frequency at coarser spatial resolution. The daily revisit time enables continuous monitoring of vegetation dynamics and crop phenology at regional to global scales.
As part of the wider Copernicus Programme, Sentinel-3 provides moderate-resolution optical and thermal observations that are especially useful for monitoring surface temperature, vegetation indices, and biophysical parameters. To view and download data products, or to explore the historical archive of all Copernicus missions (including Sentinel and MODIS products), users can easily access the data via the Copernicus Browser (https://browser.dataspace.copernicus.eu).
In addition to publicly funded missions, commercial satellite constellations can provide complementary data at high spatial or temporal resolutions. Planet (Planet Labs PBC) operates the largest mission of commercial smallsats (miniature satellites). Since 2016, the Dove constellation has imaged the Earth daily at 3–5 m spatial resolution, with the third-generation SuperDove satellites, launched from 2019 onward, capturing imagery across eight spectral bands. Planet imagery is commercially available, as opposed to Landsat, MODIS and Sentinel imagery which is free for public use.