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Aeolian processes and landforms
Published in Richard J. Chorley, Stanley A. Schumm, David E. Sugden, Geomorphology, 2019
Richard J. Chorley, Stanley A. Schumm, David E. Sugden
Aeolian processes can be treated as any other sediment transport situation in that there is erosion, transportation and deposition. Sand, of course, is a common aeolian-transported sediment but a variety of other particulate materials can be transported in the atmosphere: silt, clay, pollen, salts, snow and ice, ash from fires and, of course, volcanic ash. It has been estimated that 500 million tons of dust is produced by soil erosion each year.
Interactions between paleochannels and aeolian processes and their implications on aeolian dune patterns
Published in Geomatics, Natural Hazards and Risk, 2019
Yongcheng Zhao, Xin Gao, Jiaqiang Lei, Shengyu Li, Qin Song, Na Zhou
The stability of these channels closely depends on the stability of the runoff of the desert channels or the groundwater levels. This dependency is particular outstanding in some aeolian dominantly controlled area. Figure 10 shows that groundwater level presents the same trend with the VFC in spatial distribution (Figure 2). The groundwater level farther than >600 m to the river banks is more than 6 m in average, which could not sustain most of the desert vegetation. The vegetation within 600 m around the river banks sustained the stability of the channel. However, when no water was supplied (no matter in form of runoff or groundwater) to the channels, they will be dammed by the aeolian dunes or buried by the aeolian sediments soon (Figure 11). The velocity of these processes mainly depends on the strength of the aeolian processes, the coverage of the vegetation, the wide and depth of the channels and the angle between the orientation of the channels and resultant sand flux direction. Finally the paleochannels will vanish and evolve into a belt-like sand source due to the deposition of aeolian sediment into the river.
Mapping of aeolian deposits of an industrial site in the arid region using the TIR bands of ASTER and study of physicochemical characters and stabilization of sand erosion
Published in Geomatics, Natural Hazards and Risk, 2022
Rajendran Sankaran, Nabil Zouari, Fadhil N. Sadooni, Zulfa Ali Al Disi, Abdulaziz Al-Jabri, Hamad Al-Saad Al-Kuwari
Aeolian processes produce vast areas of sand and dunes in the arid region and need to monitor since they frequently exceed desertification or encroaching land and degrading infrastructures of industries (Gómez et al. 2018; Sur and Chauhan 2019; Aydda et al. 2020, 2019; Delgado Blasco et al. 2020; Wen et al. 2020; Karanisa et al. 2021). Studies have proven that remote sensing techniques help to map and monitor the sand deposits and sand movements, measure migration rates of dunes and the direction of the movement of dunes, and assess the areas of sand encroachments (Crósta et al. 2003; Rowan et al. 2003; Amer et al. 2010; Engel et al. 2018; Qiu et al. 2019; Song et al. 2019; Zhao et al. 2019; Aydda et al. 2020; Delgado Blasco et al. 2020). Satellite data acquired in the visible, near-infrared, and shortwave infrared spectral regions (0.4–2.5 µm) have been widely utilized to map and study the different resources of the Earth’s surface (Hunt et al. 1973; Clark et al. 1990) but, the spectral regions are useless for detecting quartz mineral that is present in the sand deposits and dunes. Because the quartz does not show spectral features in those spectral regions and exhibits a strong doublet emissivity feature in the longwave infrared (LWIR) spectral region. The 8–14 µm (LWIR) is suitable for the identification and quantification of aeolian quartz minerals and mapping of sand deposits and dunes (Vaughan et al. 2003; Eisele et al. 2015). The image processing methods include the principal component analysis (PCA) (Chavez and MacKinnon 1994), Maximum Likelihood (ML) classification (Julien et al. 2011; Hogland et al. 2013), and NDVI (Normalized Difference Vegetation Index) (Levin et al. 2006) are utilized to map such aeolian deposits.