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Ariel N. Deutsch1, Gregory A. Neumann2, James W. Head1, Paul G. Lucey3
1Department of Earth, Environmental and Planetary Sciences, Brown University2Planetary Geology, Geophysics, and Geochemistry Laboratory, NASA Goddard Space Flight Center
3Hawaii Institute of Geophysics and Planetology, University of Hawaii at Monoa
Investigating diurnal changes in thenormal albedo of the lunar surface at 1064 nm:
A new analysis with theLunar Orbiter Laser Altimeter
NASA Exploration Science Forum - 24 July 2019 - Science From and Of the Moon
INTRODUCTION thermal environment at the Moon
Temperature (K)0 400
Nighttime
Daytime
Wavelength (nm)400 800 1200
Ort
hopy
roxe
neR
eflec
tanc
e
0.1
0.3
0.5
0.7
Data from Hinrichs et al. (1999)
INTRODUCTION temperature-dependent spectral changes
1600 2000 2400
Temperature (K)80 400
Wavelength (nm)400 800 1200
0.1
0.3
0.5
0.7
Data from Hinrichs et al. (1999)
INTRODUCTION temperature-dependent spectral changes
1600 2000 2400
Temperature (K)80 400LOLA wavelength
Ort
hopy
roxe
neR
eflec
tanc
e
Temperature (K)
50 100 150 200 250 300 350 400
0.4
0.5
0.6
Orthopyroxene En86
Data from Hinrichs et al. (1999)
INTRODUCTION temperature-dependent spectral changes
Olivine Fo86
Refl
ecta
nce
at 1
064
nm
Temperature (K)
50 100 150 200 250 300 350 400
0.4
0.5
0.6
Lunar soil 67711
Orthopyroxene En86
Data from Hinrichs et al. (1999);
INTRODUCTION temperature-dependent spectral changesR
eflec
tanc
eat
106
4 nm
Hinrichs and Lucey (2002)
How does the surface reflectance of the Moon, as measured from orbit by LOLA at 1064 nm,
change over the course of a lunar day?
RESEARCH QUESTION
METHODS diurnal reflectance changes
Determine the reflectance and temperature of the surfacefor local hours 07:00–16:00 in 1°x 1° spatial bins from 65°S to 65°N.
RESULTS diurnal reflectance changes
Determine the reflectance and temperature of the surfacefor local hours 07:00–16:00 in 1°x 1° spatial bins from 65°S to 65°N.
07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00
0°N, 180°E
Detector 3
0°N, 0°E
RESULTS diurnal reflectance changes
Determine the reflectance and temperature of the surfacefor local hours 07:00–16:00 in 1°x 1° spatial bins from 65°S to 65°N.
07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00
0°N, 180°E
294 K 342 K392 K
0°N, 0°E
RESULTS diurnal reflectance changes
Determine the reflectance and temperature of the surfacefor local hours 07:00–16:00 in 1°x 1° spatial bins from 65°S to 65°N.
07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00
0°N, 180°E
294 K 342 K392 K
0°N, 0°E
Colder Warmer
Brighter Darker
RESULTS diurnal reflectance changes
Local time
07:00–08:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
09:00–10:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
12:00–13:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
Normal albedo at 1064 nm
RESULTS diurnal reflectance changes
Local time
14:00–15:00
Detector 1
0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
07:00–08:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
09:00–10:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
12:00–13:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
Normal albedo at 1064 nm
RESULTS diurnal reflectance changes
Local time
14:00–15:00
Detector 1
0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
07:00–08:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
09:00–10:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
Local time
12:00–13:00
Detector 1
Normal albedo at 1064 nm0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
Normal albedo at 1064 nm
RESULTS diurnal reflectance changes
Local time
14:00–15:00
Detector 1
0.30
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0.10
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
RESULTS diurnal reflectance changes
∆R/∆TDarker
when colder
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
Brighter when colder
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°0
positivenegative
What temperature-dependent changes are occuring?
RESULTS diurnal reflectance changes
What temperature-dependent changes are occuring?
∆R/∆T*1000
-1
00°-60°-120°-180° 180°120°60°
50°N
25°N
0°
25°S
50°S
1. LOLA measures a higher surface reflectance across the lunar surface at colder temperatures.
2. The change in albedo is relatively small (only a few %) from 07:00 to 12:00.
3. The ∆R/∆T*1000 is [-1 0] 1/K on average.
Brighter when colder
IMPLICATIONS LOLA as a mineralogical sensor?
Where are the greatest temperature-dependent changes occuring?
OPX wt. %
Lemelin et al. (2016)
50
0
∆R/∆T*1000
-1
00°-60°-120°-180° 180°120°60°
50°N
25°N
0°
25°S
50°S
50°N
25°N
0°
25°S
50°S
Brighter when colder
We observe a higher normal albedo of the lunar surface when the temperature is lower, as measured by LOLA at 1064 nm.
This is consistent with:1. Laboratory observations of pure minerals.
(Singer and Roush, 1985; Roush and Singer, 1986, 1987; Hinrichs and Lucey, 2002)
2. Ground-based observations of A-type asteroids. (Lucey et al., 1998)
3. Spacecraft-based observations of Eros. (Lucey et al., 2002)
On the space-weathered Moon, the magnitude oftemperature-dependent spectral effects is relatively low.
Ongoing work consists of determining the causes of these changes.
Future science of and from the Moon should account for temperature-dependent spectral effects.
CONCLUSIONS
Temperature (K)
50 100 150 200 250 300 350 400
Refl
ecta
nce
0.4
0.5
0.6
Orthopyroxene En86
Data from Hinrichs et al. (1999)
Olivine Fo86
IMPLICATIONS LOLA as a mineralogical sensor
IMPLICATIONS LOLA as a mineralogical sensor
Olivine
Low-Ca Pyroxene
Clinopyroxene
Plagioclase
∆R/∆T*1000
-1
0
Hinrichs and Lucey (2001)
INTRODUCTION temperature-dependent spectral changes
Pyroxene
Olivine
IMPLICATIONS LOLA as a mineralogical sensor
Where are the greatest temperature-dependent changes occuring?
60°N
30°N
0°
30°S
60°S
60°N
30°N
0°
30°S
60°S
0°-60°-120°-180° 180°120°60°
0°-60°-120°-180° 180°120°60°
∆R/∆T * 1000 moreless
0 -1
Wavelength (μm)
1.0
Refl
ecta
nce
0.4
0.2
0.0
0.6
0.8
1.0
1.2 1.4 1.6 1.80.8
Data from Lucey et al. (1998)
Fa11 83 K173 K273 K373 K448 K
446 Aeternitas
INTRODUCTION temperature-dependent spectral changes
IMPLICATIONS LOLA as a mineralogical sensor
Where are the greatest temperature-dependent changes occuring?
OPX wt. %
Lemelin et al. (2016)
50
0
∆R/∆T*1000
-1
00°-60°-120°-180° 180°120°60°
50°N
25°N
0°
25°S
50°S
50°N
25°N
0°
25°S
50°S
Temperature (K)
50 100 150 200 250 300 350 400
Refl
ecta
nce
0.4
0.5
0.6
Data from Hinrichs et al. (1999)
M
Plot (R,T) for 7-16 for regions that are ortho rich
1.
MM
HH
H
IMPLICATIONS LOLA as a mineralogical sensor
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
07:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
08:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
09:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
10:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
11:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
12:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
13:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
14:00
RESULTS diurnal reflectance changes
Temperature (K)50 400
Local time
15:00
IMPLICATIONS future measurements
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