Field evaluation of some sand transport models

Abstract

Fluorescent tracer procedures, originally developed for research on fluvial sediment movement, were used to monitor the movement of three commercially purchased sands in a natural dune environment. Results were compared with estimates of transport rates from three theoretical models. Estimates from models by Bagnold (1941) and Hsu (1971) were larger by as much as one order of magnitude than the rates observed in the tracer study. The model of A. A. Kadib (1965) provided closer correspondence to observed transport rates for medium sand (mean diam. 0.653 mm) but underestimated rates for coarse sand (mean diam. 0.992 mm).

Blown‐sand transport rate

“…The reexamination of the sand transport rate measurements by Horikawa and Shen (1960) led Chien and Wan (1983) to conclude that the three formulae tested were only partially sensitive to the wind velocity: when the friction velocity was below 40 cm s −1 , the Kawamura (1951) formula exhibited the best agreement; and for friction velocity in the 40-70 cm s −1 range, the Bagnold (1941) formula performed best. However, a field investigation by Berg (1983) found that rates predicted with the Bagnold (1941) and Hsu (1971) formulae were larger, by as much as one order of magnitude, than those measured in the study. The Kadib (1965) formula provided a close fit to observed transport rates for medium sand, mean diameter d = 0·653 mm, but underestimated observed rates for a coarser sand (d = 0·992 mm).…”

Aeolian dynamics of transgressive dunefields on the southern Mozambique coast, Africa

“…The lowest sand mobility was registered in 2000 with rainfall = 1601 mm/yr, and the highest index was registered in 2003 at 187 and rainfall = 354 mm/yr. El Niño impacts were observed irregularly in 1982, 1983, 1991, 1992, 2004, while the La Niña indicators were observed in 1975, 1981, 1984, 1994, 1995, 2000, 2007, 2009and 2011 (Table II). Precipitation analyses indicated monthly averages of 71 mm between 1969 and 1979, 63 mm from 1980 and 1989, 65.4 mm from 1990 and 1999, and 65 mm from 2000 to 2012.…”

Aeolian sand transport: a wind tunnel model

“…An underlying problem is that none of the currently available models have proven to be broadly applicable in the sense that they can provide acceptable accuracy at a wide range of sites . The ratio of predicted to the field observed transport rate may range from 0.65 to 300 (Svasek and Terwint, 1974;Berg, 1983;Bauer et al, 1990;Sherman, 1990;Nordstrom and Jackson, 1992;. The disagreements between predicted and observed transport rate are largely attributed to the required ideal conditions.…”