Author(s): Martin Richard; Brian Morse
Linked Author(s): Brian Morse
Keywords: No keywords
Abstract: This paper characterizes surface ice in a tidal reach near Quebec City, Canada. Based on 3600 rectified images, surface floe dimension statistics are presented. A few kilometers downstream of the site, where the St. Lawrence Estuary is very wide, floe diameters can reach several hundred meters. At this site, the typical diameter is similar to that measured at a site some 130 km upstream. The conclusion is that floe diameter is strongly dependent on channel dimensions. Based on an analysis of 116,000 data, the ice thickness histogram of the surface floes is also presented. Thickness was found to be related not only to recent air temperatures but also significantly related to solar radiation. Surface ice discharge is also calculated. It is shown to be highly variable in both upstream and downstream directions. This is consistent with variations in maximum ebb and flood tide water discharge that is easily six times the net (river) flow rate. Due to the presence of secondary currents, significant hysteresis was present in the tidal ice discharge. Hence, the net ice discharge could not be ascertained. Finally, the use of a laser to measure ice accumulation on tidal flats is presented and discussed.
Year: 2008