ИСТИНА

We constructed M³-based global maps of the integrated 3-μm band depth (OHIBD), relying on a refined analysis framework which performs a correction for the thermal emission component using a physically-based method extending the approach of Shkuratov et al. (2011), where also the surface roughness is taken into account. In the lunar morning and afternoon, the OHIBD increases with latitude, but much less strongly than found in Pieters et al. (2009). The OHIBD amplitude in the course of the lunar day is higher for maria than for highlands, whereas the absolute OHIBD level is lower for maria. High-Ti maria exhibit the lowest OHIBD level. In the highlands, the 3-μm band is only slightly less pronounced at midday than in the morning and afternoon. Our results are generally consistent with OH/H2O being formed by adsorption of solar wind protons, but they also suggest that in particular in the lunar highlands a strongly bounded surficial H2O/OH component is present, which is stable against diffusive loss and photolysis.