title: Polarised multiangular reflectance measurements using the finnish geodetic institute field goniospectrometer.
abstract: The design, operation, and properties of the Finnish Geodetic Institute Field Goniospectrometer (FIGIFIGO) are presented. FIGIFIGO is a portable instrument for the measurement of surface Bidirectional Reflectance Factor (BRF) for samples with diameters of 10 - 50 cm. A set of polarising optics enable the measurement of linearly polarised BRF over the full solar spectrum (350 - 2,500 nm). FIGIFIGO is designed mainly for field operation using sunlight, but operation in a laboratory environment is also possible. The acquired BRF have an accuracy of 1 - 5% depending on wavelength, sample properties, and measurement conditions. The angles are registered at accuracies better than 2°. During 2004 - 2008, FIGIFIGO has been used in the measurement of over 150 samples, all around northern Europe. The samples concentrate mostly on boreal forest understorey, snow, urban surfaces, and reflectance calibration surfaces.
authors.affiliation: Finnish Geodetic Institute, Box 15, 02431 Masala, Finland; E-Mails:  teemu.hakala@fgi.fi  (T.H.);  jouni.peltoniemi@fgi.fi  (J.P.);  eetu.puttonen@fgi.fi  (E.P.).
authors.forename: Juha
authors.initials: J
authors.lastname: Suomalainen
authors.forename: Teemu
authors.initials: T
authors.lastname: Hakala
authors.forename: Jouni
authors.initials: J
authors.lastname: Peltoniemi
authors.forename: Eetu
authors.initials: E
authors.lastname: Puttonen