LRO DIVINER Global High-Resolution Mosaics (GHRMs)

GHRM – Global High-Resolution Mosaic

Instrument:Diviner Lunar Radar Experiment

PDS4 Bundle:urn:nasa:pds:lro_diviner_derived1DOI: 10.17189/wj0s-w188Citations of DOI: 10.17189/wj0s-w188

For more information about Diviner GHRM products, see the RDR and Derived Product SIS.

The Diviner Lunar Radar Experiment Global High-Resolution Mosaics (GHRMs) are cylindrical maps gridded at 128 ppd spanning 70˚S to 70˚N latitude. These products include:

  • Channel 6-9 brightness temperature (e.g., tb6), bolometric temperature (tbol), and regolith temperature (treg). These are each calculated at midnight (m) and slope adjusted midnight (sam)

  • Derived rock abundance (ra) at slope-adjusted midnight.

  • Bolometric temperature and regolith temperature anomaly at slope adjusted midnight (anom).

The production of these products is described in detail in Powell et al., JGR: Planets, 128, e2022JE007532, 2023.

The channel 6-9 brightness temperature maps are derived from Diviner Level 1 RDR radiances for observations with emission angles <15˚ acquired from 5-July-2009 to 01-August-2022. Data are gridded at 128 ppd and 0.25 hours of local time. For each spatial bin and channel, empirical fitting is used to calculate the brightness temperature at midnight and slope-adjusted midnight. Slope-adjusted midnight is a local time that is shifted from midnight by the east-west component of the slope angle.

Bolometric temperatures are derived from the channel 6-9 brightness temperatures as described in Paige et al., Science 330, 479, 2010. Rock abundances and regolith temperatures are derived from fitting the channel 6, 7, and 8 brightness temperatures to a two-component model that assumes each spatial bin is composed of an unknown mixture of rock and regolith, as described in section 2.2.3 of the RDR and Derived Product SIS, as well as Bandfield et al., JGR: Planets, 116, E00H02, 2011 and Powell et al., JGR: Planets, 128, e2022JE007532, 2023.

Temperature anomaly is the difference between the Diviner temperature at slope-adjusted midnight and the expected temperature for typical regolith, as determined by a thermophysical model. The thermophysical model accounts for effects such as latitude, slope, scattering and emission from surrounding terrain, and shadowing by topography. This model is described in Powell et al., JGR: Planets, 128, e2022JE007532, 2023.

Diviner GHRM products have the following file names:

dghrm_VAL_TYPE_[MINLAT][MAXLAT]_FORMAT.FORMAT (with detached PDS label accompanying it in the same directory, with the same filename except for the suffix which is .XML)

where:

VAL is The gridded value. This can either be

Channel 6, 7, 8, or 9 brightness temperature: "tb6", "tb7", "tb8", or "tb9"

Bolometric temperature: "tbol"

Regolith temperature: "treg"

Rock abundance: ra"

TYPE can be "m" for midnight, "sam" for slope-adjusted midnight, or "anom" for anomaly at slope-adjusted midnight.

MINLAT is the minimum latitude bound. Currently, all GHRM products have a minimum bound of 70s.

MAXLAT is the maximum latitude bound. Currently, all GHRM products have a maximum bound of 70n.

FORMAT is the file format of the product. This can be either tif or img.

In ODE, GHRM products have the following product IDs:

DGHRM_VAL_TYPE_70S70N_IMG.IMG

DGHRM_VAL_TYPE_70S70N_TIF.TIF