Earth Planets Space, Vol. 63 (No. 1), pp. 15-23, 2011
H. S. Fok1, C. K. Shum1, Yuchan Yi1, Hiroshi Araki2, Jinsong Ping3, James G. Williams4, Georgia Fotopoulos5, Hirotomo Noda2, Sander Goossens2, Qian Huang3, Yoshiaki Ishihara2, Koji Matsumoto2, Jürgen Oberst6, and Sho Sasaki2
1Geodetic Science, School of Earth Sciences, The Ohio State University, 125 South Oval Mall, 275 Mendenhall Lab., Columbus, OH 43210, USA
2RISE Project, National Astronomical Observatory of Japan, 2-12, Hoshigaoka, Mizusawa, Oshu, Iwate 023-0861, Japan
3Shanghai Astronomical Observatory, Chinese Academy of Sciences, Nandan Road 80, Shanghai, China, 200030
4Jet Propulsion Laboratory, California Institute of Technology, MS 238-600, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA
5Dept. of Geosciences, The University of Texas at Dallas, 800 West Campbell Rd, Richardson, TX 75080-3021, USA
6German Aerospace Center (DLR), Institute of Planetary Research, Rutherfordstraße 2, 12489 Berlin, Germany
(Received June 29, 2009; Revised June 22, 2010; Accepted August 12, 2010; Online published February 21, 2011)
Both the Chang'E-1 and SELenological and ENgineering Explorer (SELENE) lunar missions, launched in 2007, provide an opportunity for significant advances in lunar science. In particular, both orbiters provide refined lunar topography models with unprecedented finer resolution and improved accuracy, especially for the far side and the polar areas of the Moon where fewer valid measurements have been available to date. An evaluation of the derived topography models is essential for the improved interpretation of selenophysics, including a knowledge of the interior of the Moon. This study provides both external and internal accuracy assessments for the derived topographic models (note that different data sets are used, albeit independent). The external comparison, which consists of comparing the topographic models with landmarks established with lunar laser ranging and radio tracking, yields an accuracy estimate of 157 m for the Change'E-1 model and 58 m for the SELENE model (150 m and 55 m if the newly recovered Lunakhod-1 site is included). The internal comparison, consisting of crossover analysis of the altimeter data after the removal of once-per-orbital-revolution errors, yields an accuracy estimate of 206 m and 68 m, respectively. These comparisons allow the establishment of conservative estimates of accuracy of 200 m and 70 m for the Chang'E-1 and SELENE models, respectively. Given the conservative estimates on the accuracy, both models yield significant improvement by factors of 2.5 and 8, respectively, when compared with a contemporary lunar topography model, i.e., the Unified Lunar Control Network 2005 (ULCN2005).
Key words: Accuracy assessment, lunar topography, selenodesy, Chang'E-1, SELENE.