WAC TiO₂ Abundance Map

Contents: TiO₂ abundance in wt% derived from Wide Angle Camera (WAC) 321/415 nm band ratio [1].

Areal Coverage: 70°N-70°S, 0°E-360°E

Image Source: The 321 and 415 nm bands of the WAC Hapke Normalized Mosaic from ~124,300 WAC images acquired from January 21, 2010 to May 1st, 2013 [2].

Map projection: Equirectangular (centered at 0°N, 0°E; 400 m/pixel at the equator) using ephemeris data provided by Lunar Orbiter Laser Altimeter (LOLA) and Gravity Recovery and Interior Laboratory (GRAIL) teams [3] and an improved geometric camera model [4].

Estimate of TiO₂ wt% and map creation: From a linear correlation between the TiO₂ contents of returned lunar soil samples and the WAC 321/415 nm ratio at the sampling sites, the 321/415 nm ratio map was converted to the TiO₂ abundance estimate map. The areas with TiO₂ lower than the detection limit (<2 wt%) are set to 1 wt%. See [1] for more details. There are some anomalously high values in the TiO2 maps, especially at high latitudes. Values 15% should not be trusted.

Archive Products: The semi-global TiO₂ map is cut into 70° latitude by 90° longitude tiles. The tile files are named in following manner: WAC_TIO2_[projection, E for equirectangular][center latitude x10][N/S][center longitude x10]. As a supplemental material, the WAC TiO₂ map without setting the areas of <2 wt% as 1 wt% is also available as tiles named: WAC_TIO2_RATIO_[projection, E for equirectangular][center latitude x10][N/S][center longitude x10]. Notice that the TiO₂ variations below 2 wt% (= detection limit) do not correspond to the TiO₂ abundance.

TiO₂ Abundance Map

Product Name	Latitude Range	Longitude Range
WAC_TIO2_E350N0450	0° to 70°	0° to 90°
WAC_TIO2_E350S0450	-70° to 0°	0° to 90°
WAC_TIO2_E350N1350	0° to 70°	90° to 180°
WAC_TIO2_E350S1350	-70° to 0°	90° to 180°
WAC_TIO2_E350N2250	0° to 70°	180° to 270°
WAC_TIO2_E350S2250	-70° to 0°	180° to 270°
WAC_TIO2_E350N3150	0° to 70°	270° to 360°
WAC_TIO2_E350S3150	-70° to 0°	270° to 360°

Supplemental Raw TiO₂ Map

Product Name	Latitude Range	Longitude Range
WAC_TIO2_RATIO_E350N0450	0° to 70°	0° to 90°
WAC_TIO2_RATIO_E350S0450	-70° to 0°	0° to 90°
WAC_TIO2_RATIO_E350N1350	0° to 70°	90° to 180°
WAC_TIO2_RATIO_E350S1350	-70° to 0°	90° to 180°
WAC_TIO2_RATIO_E350N2250	0° to 70°	180° to 270°
WAC_TIO2_RATIO_E350S2250	-70° to 0°	180° to 270°
WAC_TIO2_RATIO_E350N3150	0° to 70°	270° to 360°
WAC_TIO2_RATIO_E350S3150	-70° to 0°	270° to 360°

Product Citation:

When citing this product, use the following reference: Sato, H., Robinson, M. S., Lawrence, S. J., Denevi, B. W., Hapke, B., Jolliff, B. L., & Hiesinger, H. (2017). Lunar Mare TiO2 Abundances Estimated from UV/Vis Reflectance. Icarus, 296, 216-238. doi:10.1016/j.icarus.2017.06.013.

RDR SIS:

http://lroc.sese.asu.edu/data/LRO-L-LROC-5-RDR-V1.0/LROLRC_2001/DOCUMENT/RDRSIS.PDF

References:

[1] Sato, H., Robinson, M.S., Lawrence, S.J., Denevi, B.W., Hapke, H., Jolliff, B.L., Hiesinger, H. (2017) Lunar Mare TiO2 Abundances Estimated from UV/Vis Reflectance, Icarus, 296, 216-238. doi:10.1016/j.icarus.2017.06.013.

[2] Sato, H., Robinson, M.S., Hapke, B., Denevi, B.W., Boyd, A.K. (2014) Resolved Hapke parameter maps of the Moon. Journal of Geophysical Research Planets 119, 1775-1805. doi:10.1002/2013JE004580.

[3] Mazarico, E., Rowlands, D.D., Neumann, G.A., Smith, D.E., Torrence, M.H., Lemoine, F.G., Zuber, M.T., (2012), Orbit determination of the Lunar Reconnaissance Orbiter, Journal of Geodesy, Volume 86, Issue 3, pp.193-207, doi:10.1007/s00190-011-0509-4.

[4] Speyerer, E.J., R.V. Wagner, M.S. Robinson, A. Licht, P.C. Thomas, K. Becker, J. Anderson, S.M. Brylow, D.C. Humm, M. Tschimmel (2014), Pre-flight and On-orbit Geometric Calibration of the Lunar Reconnaissance Orbiter Camera, Space Science Reviews, doi:10.1007/s11214-014-0073-3.