Airborne multifrequency L- to Ka-band radiometric measurements over forests

Microwave radiometric measurements using airborne instruments in a frequenc y range from L- to Ka-band were carried out over six broad-leaved and one c oniferous forest stands in Tuscany, Italy. Ground measurements of the main tree parameters were performed on the same stands. The analysis of the coll ected data indicated that the use of microwave emission at the highest freq uencies makes it possible to identify some forest types, whereas L-band emi ssion is more closely related to tree biomass. In this paper, the relations hips between emission and some significant tree parameters such as leaf are a index (LAI), basal area, woody volume, and crown transparency are present ed and discussed. The significant relationship between L-band emission and woody volume is further analyzed by means of a first-order radiative transf er model.