GMES Space Component Data Access: Lessons Learnt from the Implementation of Satellite-Based Irrigation Advisory Services
Vuolo, Francesco1; Groom, Andrew2; Williams, Emma2; Jimenez, Nuria3; Calera, Alfonso3; Osann, Anna3
1University of Natural Resources and Life Sciences, Vienna, AUSTRIA; 2Astrium Services, UNITED KINGDOM; 3University of Castilla-La Mancha, SPAIN

SIRIUS (Sustainable Irrigation water management and River-basin governance: Implementing User-driven Services - is a three-year research and technical development (RTD) project, co-financed by the European Commission under its 7th Framework Program (grant 262902). It has been designed to stimulate operative and sustainable development of satellite-based services for irrigation water management. The service concept has been developed as an application in the framework of the Global Monitoring for Environment and Security (GMES) initiative and it has been implemented in pilot areas in eight countries (Spain, Italy, Romania, Turkey, Egypt, Mexico, Brazil and India) mostly exploiting commercial satellite datasets available through the GMES Space Component Data Access (GSCDA) mechanism.
The SIRIUS service provision consists in acquiring satellite sensor data every 10-15 days during entire growing season / irrigation campaign, which lasts on average 3-6 months, to derive spatially distributed crops water requirement maps and other information products for irrigation water management. The information is delivered in near-real-time to the water managers, working at regional or catchment scale, and to the farmers for the day-to-day on-farm irrigation management.
The key technical requirement of the space segment of the SIRIUS service is the satellite data provision with a fast response (24/48h after image acquisition) and the need for bi-weekly sequence of high spatial resolution optical image over the pilot sites, through the agricultural growth cycle.
This acquisition strategy supporting the SIRIUS monitoring approach represented a previously untested temporal resolution challenge for the data ordering mechanisms implemented to support data delivery to GMES projects. Direct liaison between the project coordination and the Regional Managers for each pilot location established the requirements for each pilot area (i.e. spatial resolution based on average parcel size, observation frequencies, growing season durations). These requirements were reconciled against the available data quotas and orders placed through the GSCDA accordingly.
The 2012 operational campaign was successfully conducted with a total of 84 images (from Formosat, DMC-Deimos, Spot, and RapidEye) acquired over 7 test sites on 4 continents. On average 12 revisits of each pilot area were achieved with the required temporal resolution of 10-15 days. In several cases, this has been achieved by means of a "virtual constellation" of different sensors, supported by an inter-satellite cross-calibration procedure. The images were either processed centrally or delivered to the local SIRIUS service providers for the radiometric and atmospheric corrections and the estimation of various biophysical vegetation parameters leading to the final calculation of the crop water requirements. This paper reports the lessons learnt from the development of these satellite-assisted irrigation advisory services with a particular focus on the Italian pilot area operating with RapidEye satellite sensor data.