Brief communication 'Importance of slope-induced error correction in volume change estimates from radar altimetry'

In deriving elevation change rates (dH/dt) from radar altimetry, the slope-induced error is usually assumed to cancel out in repeat measurements. These measurements, however, represent a location that can be significantly further upslope than assumed, causing an underestimate of the basin-integrated volume change. In a case-study for the fast-flowing part of Jakobshavn Isbr', we show that a relatively straightforward correction for slope-induced error increases elevation change rates by up to several metres per year and significantly reduces the volume change error with respect to laser altimetry for the area of interest.