Abstract:

Wind， sediment and surface cover are the three main factors controlling dune landforms. However， the impact of sediment， especially sand supply， on dune landforms remains to be further studied. The study on the dune volume gives rise to the concept of the equivalent sand thickness （EST）. The study of EST has gone through two research stages of multiple dune and sub-dune scales. The multiple dune scalestudy showed that there is a good consistency between EST and dune height. The relationship between EST and dune height can reflect dune types and sand supply. The combination of EST and directional variability can be used to distinguish dune types in different regions. EST can characterize the sand supply on a macro level. The sub-dune scale research makes it possible to use high resolution remote sensing images to study dune/megadune landforms and their formation processes. High resolution data allow researchers to focus on details that have previously been overlooked. This may be the key to distinguishing the different types of dune. Future research should filter dune/megadune landforms on the pixel scale. Different layers obtained from different filtering windows can be used to explore the formation process of dune/megadune landforms. The application of high resolution data can correct the existing geomorphic pattern rules and explore the relationship among morphological indexes still in dispute and the physical significance represented by them. Since EST can represent total sand supply， more attention should be paid to sand supply per unit time and its spatial variation in the future. These will have a huge impact on the aeolian science and even surface processes， and push these fields forward.

Key words: equivalent sand thickness, sand supply, megadune generations, dune types, geomorphic pattern