A new approach to study terrestrial yardang geomorphology based on high-resolution data acquired by unmanned aerial vehicles(UAVs): A showcase of whaleback yardangs in Qaidam Basin, NW China

Yardangs are wind-eroded ridges usually observed in arid regions on Earth and other planets. Previous geomorphology studies of terrestrial yardang fields depended on satellite data and limited fieldwork. The geometry measurements of those yardangs based on satellite data are limited to the length, the width, and the spacing between the yardangs; elevations could not be studied due to the relatively low resolution of the satellite acquired elevation data, e.g. digital elevation models(DEMs). However, the elevation information(e.g. heights of the yardang surfaces) and related information(e.g. slope) of the yardangs are critical to understanding the characteristics and evolution of these aeolian features. Here we report a novel approach, using unmanned aerial vehicles(UAVs) to generate centimeterresolution orthomosaics and DEMs for the study of whaleback yardangs in Qaidam Basin, NW China. The ultra-high-resolution data provide new insights into the geomorphology characteristics and evolution of the whaleback yardangs in Qaidam Basin. These centimeter-resolution datasets also have important potential in:(1) high accuracy estimation of erosion volume;(2) modeling in very fine scale of wind dynamics related to yardang formation;(3) detailed comparative planetary geomorphology study for Mars, Venus, and Titan.

A Systematic Spectroscopic Study of Four Apollo Lunar Soils

A systematic spectroscopic study including Raman, Mid-IR, N1R, and VIS-NIR, is used to investigate four endmember lunar soils. Apollo soils （〈45 μm） 14163, 15271, 67511, and 71501 were selected as endmembers to study, based on their soil chemistry, maturity against space weathering, and the sampling locations. These endmembers include an anorthositic highlands soil （67511）, a low-Ti basaltic soil （15271）, a high-Ti basaltic soil （71501）, and a mafic, KREEPy, impact-melt-rich soil （14163）. We used a laser Raman point-counting procedure to derive mineral modes of the soils and the compositional distributions of major mineral phases, which in turn reflect characteristics of the main source materials for these soils. The Mid-IR, NIR, and VIS-NIR spectroscopic properties also yield distinct information on mineralogy, geochemistry, and maturity among the four soils. Knowledge of the mineralogy resulting from the Raman point-counting procedure corresponds well with bulk mineralogy and soil properties based on Mid-IR, NIR, and VIS-NIR spectroscopy. The future synergistic application of these spectroscopy methods on the Moon will provide a linkage between the results from in situ surface exploration and those from orbital remotesensing observations.