Franco Miglietta

Franco Miglietta
pas labex
pas Eurias

dates de séjour

20/02/2016 - 14/07/2017

discipline

Sciences de la terre, de l’environnement et du climat

Fonction d’origine

Directeur de recherche

Institution d’origine

IBIMET-CNR, Florence (Italie)

pays d'origine

Italie

projet de recherche

Albedo-modifying properties of olive trees in Mediterranean climate: ecological, climate change and water savings implications

Many Mediterranean schlerophyllous species have peculiar characteristics of their foliage. For instance native as well as cultivated species belonging to the Olea and Quercus genera have leaves that differ substantially in the optical properties of the upper (adaxial) and lower (abaxial) leaf surfaces. The upper surface is normally darker than the lower surface and this is mainly due to the presence of a dense hairy structure in the abaxial surface which reflects more light in the visible region. Under calm conditions (low wind and turbulence) the upper leaf side is exposed to sun while wind gusts that modify the architecture of the tree canopy often expose the lower leaf surface to incoming direct irradiance. As a consequence, windy conditions lead to an increase in the canopy albedo. Wind-driven changes in the spatial arrangement of the leaves can be responsible for a 0.02 change in albedo. Increased reflectance and, hence, reduced radiation absorbance can cause a detectable decrease in the upward longwave emission of the foliage. The Oleα project intends to further explore wind-albedo interactions in olive trees with multiple objectives:

I. Measure difference in reflectance/transmission of light of abaxial & adaxial leaf surfaces in different Olea europea cultivars and investigate how Δα varies with tree age and the aridity of the sites where olive trees are grown

II. Assess how turbulence quantitatively affects instantaneous α of mature field grown olive trees through changes in leaf orientation and the relative exposure of the two leaf surfaces to direct radiation

III. Explore, by means of modeling (LPJmL model), how changes in Δα are likely reflected by changes in yield and productivity of olive orchards in the Mediterranean region

IV. Parameterize and eventually upscale wind-albedo relationship to propose specific guidelines to maximize climate mitigation potentials achievable by the reduction of the RF of olive trees plantation in the Mediterranean region.

biographie

Francesco Miglietta accumulated, during his career (1982-present), relevant scientific experience in weed science, satellite remote sensing applications for agriculture and crop modelling with specific expertise in phenology. In the nineties he developed innovative approaches in impact studies of rising atmospheric CO2 concentrations on crops and vegetation and developed the most widespread FACE technologies (Free Air Carbon Dioxide Enrichment). He also started new research in terrestrial carbon-cycle science with reference to mass and energy exchanges between vegetated surfaces and the atmosphere that led to the launch of the first Italian SERA (Small Environmental Research Aircraft). He also recently approached innovative studies on climate change mitigation strategies in the forest and agricultural sectors.
 

Contributeur fellows

institut

01/05/2007