The slopes of Frascati overlooking Rome boast rich, volcanic soils: wine has been produced there since time immemorial. However the latest vine crop should go down in history as the single best documented harvest ever. Part of Frascati’s Controlled Origin Denomination – ‘Denominazione d’Origine Controllata’ or DOC in Italian, a wine’s legally demarcated home region – was surveyed in ultra-sharp detail using an airborne radar sensor both before and after last October’s harvest. This two-stage ESA campaign was called BACCHUS-DOC, and was intended to complement a number of radar and optical satellite acquisitions by ERS-2, SPOT, Landsat, IKONOS and QuickBird.
Following processing of raw data, the results are now under study by a team from ESRIN, ESA’s European Centre for Earth Observation located within the area of study, and the nearby University of Tor Vergata. In particular they are investigating to what extent the BACCHUS-DOC airborne and satellite radar imagery is sensitive to vineyard surfaces and the change in biomass following the grape harvest. BACCHUS-DOC was overseen by ESA’s dedicated Campaigns Unit, with the participation of the German Aerospace Center (DLR) and Rome’s University of Tor Vergata, whose personnel carried out accompanying ground measurements. The Campaigns Unit and Bacchus team selected a 24.5 square kilometre area of interest – with orientation fitting the orbit and radar look direction of ERS-2 at that time.
For their part in the campaign, DLR operated their Experimental Synthetic Aperture Radar (E-SAR), flown on their customised Dornier-228 flown out of nearby Ciampino Airport. The E-SAR has a maximum spatial resolution of four metres and operates at five different radar signal wavelengths with selectable polarisations, a means of increasing signal sensitivity to different environmental variables. Such a performance is superior to the current generation of radar satellite sensors but presents a way to simulate the results available from future space-based instruments.
The main scientific objective of BACCHUS-DOC was to investigate the sensitivity of polarimetic radar is to measurements of grape biomass, as well as additional useful parameters for inventorying and characterising vineyards such as vine rows, spacing and orientation, and vineyard limitations. The potential to estimate local soil roughness and moisture is also being assessed. Frascati was selected for the BACCHUS-DOC campaign because a dedicated GIS has been constructed for this DOC area as part of a European Commission-funded project called Bacchus, aimed at applying Earth Observation and GIS technology to improve European wine quality. Bacchus is now complete, but a follow-on project called DiVino is extending the capabilities of the Frascati GIS.
