Lunar Figure and Topography Derived from the Observation by Laser Altimeter (LALT) on the Japanese Lunar Explorer KAGUYA

Abstract

New global topographic model of the Moon with a spatial resolution less than 0.5 degrees (its angular distance is about 15 km) has been derived from the laser altimeter (LALT: Laser ALTimeter) on the Japanese lunar explorer KAGUYA (SELENE). The model reveals more detailed lunar topography than the previous global one (ULCN2005) for scales less than a few hundred kilometers. Spherical harmonic analysis of the new lunar topography shows the Moon has rougher topography than was in the previous models. Global correlation between this topographic model (STM359_grid-02) and the latest gravity model (SGM90d) and their admittance spectrum give fundamental clues for compensation of lunar topography and its evolutional restrictions. Topographic features for scales more than about 180 km (6 degrees in angular distance) are supported partly by the isostatic compensation, while other features are done by the crustal rigidity.