A Study of Reflectance Characteristics in Regions of Several Lunar Magnetic Anomalies

The Moon does not have a global magnetic-field pattern. However, at anitpodes of some large lunar craters there are magnetic fields of high strengths. The lunar magnetic anomalies are also regions of unusual lunar albedo features, which has been hypothesized to be due to the local weakening of space weathering by mini-magnetospheres induced by magnetic anomalies. The Interference Imaging Spectrometer (IIM) onboard the Chang'E-1 lunar exploration spacecraft obtained optical spectra of various parts of the lunar surface in 32 bandpasses covering visible to near-infrared wavelengths. The IIM data allow us to study effects of lunar space weathering through local reflectance curves of the lunar surface. By comparing average reflectance curves within regions of four selected magnetic anomalies to those in their close vicinities (outside the magnetic anomalies), we have found that the reflectance values within the regions of magnetic anomalies are consistently larger than in the vicinities. Considering that mini-magnetospheres shield the regions within the anomalies against space winds, our result supports the hypothesis that lunar mini-magnetospheres reduce influences of space weathering. Our study could provide new insights into effects of space weathering on the lunar surface.