A colourful patchwork of agricultural fields is pictured in this radar image captured by Copernicus Sentinel-1 over southeastern Romania.

Although satellites carrying optical, or ‘camera-like’, instruments are often used to map crop types from space, radar satellites also offer a valuable source of information for crop classification and growth patterns to help assess health and productivity.

Sentinel-1’s radar is instrumental in monitoring changes in land cover, providing critical insights for regions with intensive agriculture, as shown here.

This image combines three radar acquisitions taken at different times to show changes in crop development and land conditions.

Radar images are naturally black and white, but here each image has been assigned a colour: blue for the first image from 28 October 2024, green for the second from 9 November, and red for the third from 21 November. When the images are overlapped to obtain a single composite, the resulting colours highlight the various crop types and stages of growth.

In radar images, built-up areas like cities and towns are visible in grey or white, while bodies of water appear in black.

The Danube – the longest river in the EU – can be seen as a black, winding line in the right of the image. The city of Brăila, capital of the county and Romania’s second largest port, is visible in white next to the river at the top of the image.

Flowing northward, the Danube splits here into smaller channels that form two main islands. The bigger, Great Brăila Island, is mainly covered by agricultural fields, whose geometrical shapes are clear to see. The smaller island, Small Brăila Island, is visible in light blue and hosts the Balta Mică a Brăilei Natural Park, a protected wetland area of international importance.

Providing all-weather, day-and-night radar imagery for the global monitoring of Earth’s land and oceans, the Copernicus Sentinel-1 mission supports a diverse range of applications, such as environmental management, disaster response and climate change research.

After Sentinel-1B’s working life ended in 2022, the upcoming launch of Sentinel-1C will restore the mission to its full strength as a two-satellite constellation. Once in orbit, Sentinel-1C will not only continue the mission’s legacy, but, notably, will also introduce enhanced capabilities for monitoring maritime traffic, further expanding the mission’s utility.