This paper presents a quantitative investigation of the relative importance
of variations in incidence angle, land cover type, month of the year, and
the presence or otherwise of a wet snow cover, in modulating the C-band VV
backscattering coefficient from upland terrain in Scotland. We show that, p
rovided the contributions from incidence angle and land cover are modelled,
the uncertainty in a backscatter measurement can be reduced to approximate
ly 1 dB. At this level of precision, a difference can be observed from a sn
ow-covered area in the case of heather and rough grass, the two dominant up
land vegetation types. Over heather-covered areas, a wet snow cover typical
ly reduces the backscatter by 2 dB whereas over rough grass it is increased
by about 1 dB. Densely forested areas exhibit no significant change in bac
kscattering coefficient as a result of a wet snow cover, a result in accord
ance with previous research.