Cosmos Editorial
Rice paddies can be picturesque, but rarely this colourful.
This view of rice-growing areas of the Mekong Delta in Vietnam was taken by the European Space Agency’s Copernicus Sentinel-1 mission.
The multi-temporal image in fact combines three radar acquisitions taken around one month apart to show changes in crop and land conditions over time.
The first image (28 October 2019) picks out changes in pink and red, the second (21 November) in green, and the third (27 December) in blue. The majority of growth in the rice fields is visible in December.
The grey represents either built-up areas or patches of land that saw no changes during this time.
Bodies of water reflect the radar signal away from the satellite, making water appear dark. This can be seen in the Bassac River in the right of the image. Ships in the river can be seen as bright, multi-coloured dots.
Radar sensors are particularly useful for monitoring and mapping rice cultivation because of their ability to detect waterlogged ground and penetrate the humid cloud coverage typical in Asia.