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Topographic roughness of the northern high latitudes of Mercury from MESSENGER Laser Altimeter data
Author(s) -
Fa Wenzhe,
Cai Yuzhen,
Xiao Zhiyong,
Tian Wei
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068120
Subject(s) - geology , impact crater , altimeter , terrain , mercury (programming language) , latitude , surface finish , root mean square , surface roughness , geodesy , geomorphology , astrobiology , geography , physics , materials science , cartography , engineering , quantum mechanics , computer science , electrical engineering , composite material , programming language
We investigated topographic roughness for the northern hemisphere (>45°N) of Mercury using high‐resolution topography data acquired by the Mercury Laser Altimeter (MLA) on board the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Our results show that there are distinct differences in the bidirectional slope and root‐mean‐square (RMS) height among smooth plains (SP), intercrater plains (ICP), and heavily cratered terrain (HCT), and that the ratios of the bidirectional slope and RMS height among the three geologic units are both about 1:2:2.4. Most of Mercury's surface exhibits fractal‐like behavior on the basis of the linearity in the deviograms, with median Hurst exponents of 0.66, 0.80, and 0.81 for SP, ICP, and HCT, respectively. The median differential slope map shows that smooth plains are smooth at kilometer scale and become rough at hectometer scale, but they are always rougher than lunar maria at the scales studied. In contrast, intercrater plains and heavily cratered terrain are rough at kilometer scale and smooth at hectometer scale, and they are rougher than lunar highlands at scale <∼2 km but smoother at >∼2 km. We suggest that these scale‐dependent roughness characteristics are mainly caused by the difference in density and shape of impact craters between Mercury and the Moon.