等效沙厚度研究进展

Reviews on the research of equivalent sand thickness

风、沉积物和地表覆盖是控制沙丘地貌的三大要素。沉积物尤其是沙源供应对沙丘地貌的影响仍有待深入研究。沙丘体积的研究促使了等效沙厚度(equivalent sand thickness,EST)概念的提出。EST研究经历了多个沙丘和亚沙丘尺度2个研究阶段。多个沙丘EST研究发现,EST与沙丘高度之间具有较好的一致性,其与方向变率的组合可以很好地区分沙丘类型,且在宏观上可以表征沙源供应。亚沙丘尺度EST研究使得利用高分辨率遥感影像研究沙丘(山)地貌及其形成过程成为可能。未来的研究应在像元尺度上对沙丘(山)地貌进行滤波,不同滤波窗口所得到的不同图层可以用来探究沙丘(山)地貌的形成过程。

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 scale study 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.