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| Titel |
Analysis on establishing Chang'E-3 landing site as a reflectance calibration target |
| VerfasserIn |
Bin Liu, Xiaohui Fu, Xingguo Zeng, Meijuan Yao, Hongbo Zhang, Yan Su, Shu Zhao, Xiping Xue, ChunLai Li, Yongliao Zou |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250103707
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| Publikation (Nr.) |
 EGU/EGU2015-3120.pdf |
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| Zusammenfassung |
| Recent lunar orbital observations suggested that the surface reflectance calculated based on
the Apollo 16 standard area and Apollo 16 sample laboratory measurement is significantly
different from its true value [1-3], one reason is the composition and maturity differences
between the 62231 sampling site and the Apollo 16 standard site existed, the other reason is
the physical properties of the returned lunar sample, such as porosity, have been changed
during the sampling operations. So more new standard targets on the Moon, besides
the widely used Apollo 16 area, are needed for imaging spectrometers on lunar
missions to improve their reflectance calibration accuracies. The Chang’E-3 VIS/NIR
Imaging Spectrometer (VNIS), which is just fixed at the front of the Yutu rover [4],
equipped with a white spectralon panel as reflectance calibration standard, can
perform in situ multispectral observations around the Chang’E-3 landing site without
altering the physical and mineralogical natures of lunar soils. Therefore, it provides
an opportunity to establish a new reliable standard target for in-flight reflectance
calibration.
The reflectance calibration target should be compositional homogeneous, the topography
of which must be flat, and the reflectance should be identical with no nearby units of other
different materials. As we have known, Chang’e-3 probe landed on the Mare Imbrium basin
in the east part of Sinus Iridum, the landing site is relatively flat at a spatial coverage of
~660km2, and this region belongs to Eratosthenian low-Ti/high-Ti mare basalts
[5-6]. According to much higher resolution topography data, elemental data and
reflectance data of Chang’E-2 and Chang’E-3[7-8], we preliminary analyse the
possibility on establishing Chang’E-3 landing site as a reflectance calibration target.
Firstly, the overall terrain of the 4 kmx4 km area around the landing site is flat, but
there are still three bigger craters existed. Secondly, the composition on Chang’E-3
landing site is homogeneous according to the two detection results of APXS on
elements in lunar soil. At last, we compare and scale the four detection points’
reflectance of VNIS, which demonstrate that the reflectance of the landing site are quite
similar at the spectral range 450nm-1750nm, but differences still existed beyond
1750nm.
Future work is still needed, such as photometric calibration of VNIS data, and errors
estimation on reflectance calculation. Besides, the location and spatial coverage of the
reflectance calibration target should be determined and its calibration accuracy should be
evaluated.
Acknowledgements: This work was supported by the National Natural Science
Foundation of China (No.11403049 and 41490633).
References: [1]ÂJ. K. Hillier et al., (1999) Icarus, 141, 205–225. [2]ÂM. Ohtake et al.,
(2010) Space Sci. Rev., 154, 57-77. [3]ÂM. Ohtake et al., (2010) Icarus, 226, 364-374. [4] B.
Liu et al., (2014) RAA, 14, 1674. [5] L. Qiao et al., (2013) Sci Sin-Phys Mech Astron, 43,
1370-1386. [6] J. N. Zhao et al., (2014) Sci China-Phys Mech Astron, 57, 569-576. [7]
C. L. Li et al., (2014) RAA, 14, 1514. [8] X. H. Fu et al., (2014) RAA, 14, 1595. |
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