Limits...
High-resolution local gravity model of the south pole of the Moon from GRAIL extended mission data.

Goossens S, Sabaka TJ, Nicholas JB, Lemoine FG, Rowlands DD, Mazarico E, Neumann GA, Smith DE, Zuber MT - Geophys Res Lett (2014)

Bottom Line: Our solution consists of adjustments with respect to a global model expressed in spherical harmonics.We apply a neighbor-smoothing constraint to our solution.Our local model removes striping present in the global model; it reduces the misfit to the KBRR data and improves correlations with topography to higher degrees than current global models.

View Article: PubMed Central - PubMed

Affiliation: CRESST, University of Maryland Baltimore County Baltimore, Maryland, USA ; NASA Goddard Space Flight Center Greenbelt, Maryland, USA.

ABSTRACT

: We estimated a high-resolution local gravity field model over the south pole of the Moon using data from the Gravity Recovery and Interior Laboratory's extended mission. Our solution consists of adjustments with respect to a global model expressed in spherical harmonics. The adjustments are expressed as gridded gravity anomalies with a resolution of 1/6° by 1/6° (equivalent to that of a degree and order 1080 model in spherical harmonics), covering a cap over the south pole with a radius of 40°. The gravity anomalies have been estimated from a short-arc analysis using only Ka-band range-rate (KBRR) data over the area of interest. We apply a neighbor-smoothing constraint to our solution. Our local model removes striping present in the global model; it reduces the misfit to the KBRR data and improves correlations with topography to higher degrees than current global models.

Key points: We present a high-resolution gravity model of the south pole of the Moon Improved correlations with topography to higher degrees than global models Improved fits to the data and reduced striping that is present in global models.

No MeSH data available.


Related in: MedlinePlus

The root-mean-square (RMS) of fit to the KBRR data for GRGM900A and the local model, for the December arcs where the satellite altitude above topography was at its lowest.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4459178&req=5

fig02: The root-mean-square (RMS) of fit to the KBRR data for GRGM900A and the local model, for the December arcs where the satellite altitude above topography was at its lowest.

Mentions: The fits to the KBRR data for the global and local models, using short arcs over the selected area for both, are shown in Figure 2. The fits for the local model were computed by adding the acceleration contributions of the adjustments Δgadj using equation 1 to the global model GRGM900A in the short-arc orbit determination. This shows that our local model fits the KBRR data better than the global starting model, sometimes by a considerable amount: on average, the fits improve by 12% for the whole extended mission and by 43% for the low December arcs only. There are still high fits for certain periods, most notably around 5 and 8 December, where the GRAIL satellites had their lowest periapsis heights. This indicates that information beyond degree and order 1080 is still present in the data, especially considering that the fit for those arcs is still well above the intrinsic noise levels of the data, which is thought to be between 0.05 and 0.07 μm/s (N. Harvey, Jet Propulsion Laboratory, Pasadena, CA, unpublished data, 2013). Figure 2 shows the fits for the last part of the GRAIL extended mission because the improvements are most clear there. The fits also improve for the earlier arcs in the extended mission, although there they are very close to the global model fits, at ∼0.12μm/s.


High-resolution local gravity model of the south pole of the Moon from GRAIL extended mission data.

Goossens S, Sabaka TJ, Nicholas JB, Lemoine FG, Rowlands DD, Mazarico E, Neumann GA, Smith DE, Zuber MT - Geophys Res Lett (2014)

The root-mean-square (RMS) of fit to the KBRR data for GRGM900A and the local model, for the December arcs where the satellite altitude above topography was at its lowest.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4459178&req=5

fig02: The root-mean-square (RMS) of fit to the KBRR data for GRGM900A and the local model, for the December arcs where the satellite altitude above topography was at its lowest.
Mentions: The fits to the KBRR data for the global and local models, using short arcs over the selected area for both, are shown in Figure 2. The fits for the local model were computed by adding the acceleration contributions of the adjustments Δgadj using equation 1 to the global model GRGM900A in the short-arc orbit determination. This shows that our local model fits the KBRR data better than the global starting model, sometimes by a considerable amount: on average, the fits improve by 12% for the whole extended mission and by 43% for the low December arcs only. There are still high fits for certain periods, most notably around 5 and 8 December, where the GRAIL satellites had their lowest periapsis heights. This indicates that information beyond degree and order 1080 is still present in the data, especially considering that the fit for those arcs is still well above the intrinsic noise levels of the data, which is thought to be between 0.05 and 0.07 μm/s (N. Harvey, Jet Propulsion Laboratory, Pasadena, CA, unpublished data, 2013). Figure 2 shows the fits for the last part of the GRAIL extended mission because the improvements are most clear there. The fits also improve for the earlier arcs in the extended mission, although there they are very close to the global model fits, at ∼0.12μm/s.

Bottom Line: Our solution consists of adjustments with respect to a global model expressed in spherical harmonics.We apply a neighbor-smoothing constraint to our solution.Our local model removes striping present in the global model; it reduces the misfit to the KBRR data and improves correlations with topography to higher degrees than current global models.

View Article: PubMed Central - PubMed

Affiliation: CRESST, University of Maryland Baltimore County Baltimore, Maryland, USA ; NASA Goddard Space Flight Center Greenbelt, Maryland, USA.

ABSTRACT

: We estimated a high-resolution local gravity field model over the south pole of the Moon using data from the Gravity Recovery and Interior Laboratory's extended mission. Our solution consists of adjustments with respect to a global model expressed in spherical harmonics. The adjustments are expressed as gridded gravity anomalies with a resolution of 1/6° by 1/6° (equivalent to that of a degree and order 1080 model in spherical harmonics), covering a cap over the south pole with a radius of 40°. The gravity anomalies have been estimated from a short-arc analysis using only Ka-band range-rate (KBRR) data over the area of interest. We apply a neighbor-smoothing constraint to our solution. Our local model removes striping present in the global model; it reduces the misfit to the KBRR data and improves correlations with topography to higher degrees than current global models.

Key points: We present a high-resolution gravity model of the south pole of the Moon Improved correlations with topography to higher degrees than global models Improved fits to the data and reduced striping that is present in global models.

No MeSH data available.


Related in: MedlinePlus