ERA: a dedicated research aircraft to monitor mass and energy exchange of Mediterranean ecosystems

Airborne measurement of wind and turbulence is a reality since few decades for scientific and meteorological atmospheric research applications. With the coming of a new generation of low cost, low consumption and fast response sensors it is now possible to use small aircrafts for such applications. The advantages are a limited cost both of the platform itself and of its management, the possibility to fly at very low altitude and reduced speed for a higher measurement's precision, reduced flow distorsion. In 1999 Iniziative Industriali Italiane, an Italian Small-Medium Enterprise recognized the excellent capacities for this kind of applications of its homemade aircrafts, the Sky Arrows. The company started the study the preparation of a certified aircraft (JAR VLA) equipped with the NOAA/ARA sensors. The first Sky Arrow ERA (Environment Research Aircraft) was born in 2000 and is now operated by the San Diego University (USA), Global Change Research Group (SDSU) under the guidance of Prof. Walt Oechel. This group is making airborne flux measurements in the artic regions of North Alaska, in very severe environmental conditions. CNR has promoted the introduction of this technology in European research. Measurements campaigns of 2 to 3 weeks length were performed in the context of the RECAB project - both in summer and in winter in each country in selected locations, where also tower based flux measuring infrastructures were already present in the frame of the CARBOEUROPE cluster. In the spring of 2002, CNR ISAFOM assembled one of such stations in Tuscania (Viterbo), to compare NEE with aircraft based flux measurements. ERA also performed flights in 2001 and 2002 on the island of Pianosa, aimed at assessing total NEE of the island. CNR ISAFoM was recently funded by MIUR (Italian Ministry of Research and Education) a 2 year project to purchase and instrument 2 ERA aircraft. Latest technology sensors and electronics were used, so that a new generation GPS will be installed - and the piloting software be rewritten. When operational, the aircraft will allow many different research activities -Measuring NEE of forest and crops · -Monitor C and water vapour exchange of composite systems in non flat terrains. -Create evapotranspiration maps -Determine was use of entire basins -Elaborate thematic maps by means of GIS The focus of this paper is to report on the description of the SkyArrow platform, and on first validation results obtained by comparison of fluxes of mass, momentum, and energy measured both from towers and from the aircraft flying in the lowest levels of the atmospheric boundary layer.