CropSAR 1D

CropSAR is an innovative technique that uses Sentinel-1 radar observations to augment those of Sentinel-2. By doing so, more continuous vegetation properties monitoring can be performed, including vegetation information for situations where these properties cannot be retrieved from Sentinel-2 observations due to cloud occurrence. This technique is especially beneficial to operational agricultural monitoring, as the entire crop growth cycle can be observed, particularly the drastic changes during its development. The Sentinel-1 σ0 backscatter signal contains information on vegetation’s structure and moisture content and the underlying soil. This correlation is demonstrated in Figure 1. The CropSAR temporal resolution is defined by the combined revisit rate of Sentinel-1 and cloud-free Sentinel-2 observations. For Belgium and its surroundings (~50°N), this is almost every day (because both the ascending and descending tracks for Sentinel-1 are acquired).

A more detailed introduction to CropSAR, it’s working principles, and added value is given in this blog. The various CropSAR web service elements are explained below.

Note: CropSAR is intended to provide the augmented Sentinel-1 and -2 vegetation indices for individual agricultural fields. Although it can be requested over larger areas (e.g. at the community level), the added value for such areas will be limited, and it will take a considerable time for the algorithm to provide you with the results.

Disclaimer: Requesting CropSAR in NRT (near real-time) will result in a lower performance of the fAPAR estimates. This lower performance only occurs for the fAPAR estimates in 3 months before the real-time.

Methodology

CropSAR takes as input the cloud-interrupted time series of Sentinel-2 fAPAR and adds the uninterrupted time series of Sentinel-1 backscatter. The algorithm then returns a completely cloud-free time series of fAPAR together with its confidence level.