# Presentation: 596965

## Comparison of Telescopic + Clementine Spectra (USGS Calibration andModified USGS Calibration)

- Aristarchus Region
- Apollo 11
- Humorum
- Sulpicius Gallus

## Ground-based v Clementine

- Groundbased telescopic spectra and Clementine spectra show systematic differences
- Groundbased data show less contrast than Clementine data

- All spectra in a 5x5 km box

- Aris N Wall

- Aris Dark Ejecta

## Locations of ground-based spectra

- 1 km/pixel

## Errors relative to Albedo of Site

- 1.1 μm

- 1.25 μm

- 1.5 μm

- 2.0 μm

- Compared the Albedo of each Aristarchus site to the difference between Tele/Tele750 and Clem/Clem750.
- The difference between the USGS Clementine data and the ground-based telescopic data is proportional to the Clementine albedo in the NIR, with dark locations having low reflectances and bright locations having high reflectances relative to the ground-based data.  Intermediate albedos show the smallest error

## Correction Process

- Compared USGS Clem spectra to ground-based spectra at each wavelength for all 14 locations in Aristarchus region
- At each wavelength, found gain and offset that minimized the differences between
- Telescopic /Telescopic750 and
- [(Clem  gain)+offset]/Clem750

- Example: 2 μm band

## Optimized Gains & Offsets

| Wavelength | Gain | Offset |
| --- | --- | --- |
| 0.415 | 1.000 | 0.0000 |
| 0.750 | 1.000 | 0.0000 |
| 0.900 | 1.012 | -0.0004 |
| 0.950 | 1.036 | -0.0008 |
| 1.000 | 1.056 | -0.002 |
| 1.100 | 0.870 | 0.0246 |
| 1.250 | 0.854 | 0.0316 |
| 1.500 | 0.792 | 0.0514 |
| 2.000 | 0.742 | 0.0680 |

## Aristarchus N Wall

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus Dark Ejecta

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Now, correction derived from Aristarchus region applied to Apollo 11, Humorum and Sulpicius Gallus...

## Apollo 11

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Humorum Pyroclastics

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Sulpicius Gallus Pyroclastics

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Comparison of FeO derived from Clementine UVVIS (Lawrence et al 2002) and Clementine UVVIS and NIR (LeMouelic et al. 2000)

## Le Mouelic vs Lawrence

- Uses 750, 950 and 1500 bands
- LeMouelic algorithm validated locally at Aristarchus, Tycho and Kepler
- Validated with radiative transfer theory by Lucey 2006
- FeO derived from recent release shows no mare-highland contrast

- Lawrence

- LeMouelic

## Corrected Le Mouelic vs Lawrence

- Uses 750, 950 and 1500 bands
- 1500 band adjusted using corrections previously shown
- Good correlation with Lawrence 2002 Clementine FeO

- Lawrence

- LeMouelic

## Conclusions

- Recent USGS release is
-  inconsistent with Hawke/Pieters groundbased data
- Gives suspect FeO values using LeMouelic Algorithm

- Gains and offsets derived from Aristarchus region:
- Cause data for dark regions at Apollo 11, Sulpicius Gallus and Humorum to be more consistent with groundbased data
- Cause FeO derived from LeMouelic algorithm to be more consistent with UVVIS-only derived FeO

## Additional Aristarchus region comparisons

## Aristarchus A

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus SW Wall

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus S Floor

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus E Wall

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus Central Peak

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Herodotus Chi

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus S Rim

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus C

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Herodotus D

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus Plateau 1

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus Plateau 2

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS

## Aristarchus Plateau 3

- Best; Mean

- All spectra in a 5x5 km box

- USGS

- Modified
- USGS