The H-parameter is a measure of subsurface structure derived from Diviner Lunar Radiometer observations aboard the Lunar Reconnaissance Orbiter. These maps characterize the thermophysical properties of the upper few centimeters of the lunar regolith.

H-parameter map
Global map of the H-parameter derived from Diviner observations, revealing variations in regolith structure across the lunar surface.

Dataset Information

Property Value
Source LRO Diviner Lunar Radiometer
Coverage ±70° latitude
Resolution 128 pixels per degree
Format 32-bit floating point

Dataset Contents

The data directory contains:

  • H-parameter maps — Values in meters, representing the e-folding depth scale of the regolith density and conductivity profiles
  • Latitude and longitude grids — Corresponding coordinate arrays for georeferencing
  • Thermal inertia maps — Derived thermal inertia referenced to 273 K, at 10 pixels per degree resolution

Scientific Background

The H-parameter describes the characteristic length scale over which regolith density and thermal conductivity increase with depth due to compaction. It is the e-folding depth of the exponential density and conductivity profiles in the upper regolith.

Lower H values indicate more rapid densification with depth, corresponding to higher thermal inertia materials such as rocks or consolidated regolith. Higher H values indicate a more gradual density profile, characteristic of fine-grained, porous regolith with lower thermal inertia.

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Further information:

  • Hayne, P. O., Bandfield, J. L., Siegler, M. A., Vasavada, A. R., Ghent, R. R., Williams, J.-P., Greenhagen, B. T., Aharonson, O., Elder, C. M., Lucey, P. G., & Paige, D. A. (2017). Global regolith thermophysical properties of the Moon from the Diviner Lunar Radiometer Experiment. Journal of Geophysical Research: Planets, 122, 2371–2400. Link
  • Vasavada, A. R., Bandfield, J. L., Greenhagen, B. T., Hayne, P. O., Siegler, M. A., Williams, J.-P., & Paige, D. A. (2012). Lunar equatorial surface temperatures and regolith properties from the Diviner Lunar Radiometer Experiment. Journal of Geophysical Research: Planets, 117, E00H18. Link