Pattern analysis of dune‐field parameters

Abstract

As a basic form of pattern analysis, the parameters of dune spacing, defect density, crest orientation and crest length are measured from remote images and treated statistically for dunes at White Sands in New Mexico, the Algodones in California, the Agneitir in Mauritania, and the Namib in Namibia. Statistical populations are identified from frequency plots of dune spacing and crest length, field-scale calculations of defect density, and rose diagrams of crest orientation. Single populations characterize simple dune fields (White Sands), whereas multiple populations characterize compound/complex dunes (Algodones, Namib), and complex dune fields (Agneitir). As time increases, dune fields show an increase in dune spacing and crest length, a decrease in defect density, more tightly clustered crest orientation, and a reduction in the variance associated with measurements of these parameters. The results are consistent with models of dune fields as self-organizing complex systems in which a characteristic pattern emerges as a function of constructional time. Because pattern evolution is a function of time, it may be possible to use pattern analysis to augment current methods of age determination. Statistically defined populations can be used in geomorphic backstripping to unstack generations of simple patterns that give rise to complex patterns, and to reconstruct each generation in terms of construction time and palaeo-wind regime.

Remote sensing and spatial analysis of aeolian sand dunes: A review and outlook

“…Ewing et al (2006) provided the first comprehensive example using measurements of digitized points and lines representing dune positions at four dune fields (White Sands, New Mexico, USA; Algodones, California, USA; Agneitir, Mauritania; Namib, Namibia). Digitized points were used to represent dune defects, which denote dune terminations or breaks in pattern, while lines digitized along dune crests were used to measure dune spacing, orientation, and length.…”

“…The bulk of SA efforts have been performed by using landform objects to represent individual dunes (e.g., points and lines of Ewing et al, 2006;Wilkins and Ford, 2007;Bishop, 2007Bishop, , 2010. Discretization of dunes as objects invariably raises some fundamental and tricky questions: Where does a sand dune begin and end?…”

“…Beginning with images from the early 1970s, remote sensing (RS) has revealed a rich diversity of dune field patterns on Earth, Mars, Venus, and Titan. The synoptic perspective provided by remote sensing imagery has, however, only recently stimulated a shift away from the singledune studies popularized in the 1980s and 1990s (Livingstone et al, 2007) towards dune field-scale studies that incorporate spatial analysis (SA) of boundary conditions, dune activity, dune patterns and hierarchies, and dune-dune relations (e.g., Tsoar and Blumberg, 2002;Hugenholtz and Wolfe, 2005a;Kocurek and Ewing, 2005;Mitasova et al, 2005;Ewing et al, 2006;Bishop, 2007;Wilkins and Ford, 2007;Ewing and Kocurek, 2010a,b;Hugenholtz and Barchyn, 2010;Kocurek et al, 2010).…”

“…Advances in computer hardware and software throughout the 1990s facilitated a shift in study to the reflectance characteristics of dune surfaces (Paisley et al, 1991;Lancaster et al, 1992;Tsoar and Karnieli, 1996;Walden and White, 1997;White et al, 1997;Blumberg, 1998;Pease et al, 1999) and innovative approaches for quantifying historical changes in dune activity (Anthonsen et al, 1996;Brown and Arbogast, 1999). In the last decade, additional progress has been made in the quantitative analysis of dune morphodynamics Vermeesch and Drake, 2008;Bourke et al, 2009;Necsoiu et al, 2009) and dune field pattern analysis (Kocurek and Ewing, 2005;Ewing et al, 2006;Bishop, 2007;Wilkins and Ford, 2007;Mason et al, 2008;Bishop, 2010;Ewing and Kocurek, 2010a,b;Hugenholtz and Barchyn, 2010;Kocurek et al, 2010).…”

Recent advances in research on the aeolian geomorphology of China's Kumtagh Sand Sea

“…Gravel bodies under the combined effects of diluvial and aeolian erosion are found in the north of the Kumtagh Sand Sea (Dong et al, 2010b). The special geomorphic patterns of the region covered with the linear dunes in the north of the desert are analysed with the method of geomorphological pattern analysis (Dong et al, 2010b); this method consists in analysing the relationship between cumulative frequency plots of dune spacing and crest length to create statistical populations, and has been introduced to dune geomorphology in recent years (Ewing et al, 2006).…”