Much of the Martian surface is covered by a weathering layer (regolith or soil) produced by long-term surface processes such as impact gardening, eolian erosion, water weathering, and glacial modifications. China’s first Martian mission, Tianwen-1, employed the Mars Rover Penetrating Radar (RoPeR) to unveil the detailed structure of the regolith layer and assess its loss tangent. The RoPeR radargram revealed the local regolith layer to be highly heterogeneous and geologically complex and characterized by structures that resemble partial or complete crater walls and near-surface impact lenses at a very shallow depth. However, comparable radar data from the Lunar far side are rather uniform, despite the two surfaces being geologically contemporary. The close-to-surface crater presented in this study shows no detectable surface expression, which suggests an accelerated occultation rate for small craters on the surface of Mars as compared to the rate on the Moon. This is probably due to the relentless eolian processes on the Martian surface that led to the burial of the crater and thus shielded it from further erosion. The high loss tangent indicates that the regolith at the Tianwen-1 landing site is not dominated by water ice.

No abstract

With the proposal of a sustainable development strategy, the development of new energy is accelerating day by day. The impact of new energy on economic growth has become increasingly apparent. Therefore, this article will analyse the characteristics and development status of new energy. This article focuses on the analysis of the development of new energy in China, including the current data on wind energy and biomass energy in China, so as to put forward the influence factors of the development of new energy on economic construction. At the same time, it also proposed a new energy development strategy centred on economic growth. The purpose of this article is to guide the coordinated development of new energy development and economic growth.

No abstract

On Mars, compared to an airless body such as the Moon, the weathering layer ("regolith", a general term for the layer of fragmental and unconsolidated rock material, whether residual or transported and of highly varied character, that nearly everywhere forms the surface of the land and overlies or covers bedrock) underwent complicated geological processes in addition to weaker impact and space weathering modifications. A fuller understanding of the stratigraphy and properties of the martian regolith would unravel the local evolution history and help address key geological questions, including the potentiality of liquid water on the surface or near-surface (Christensen et al., 2008). The characterization of the dielectric properties of the weathering layer represents a key target of this quest.Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) and the Mars Express orbiter and the Shallow Radar (SHARAD) have revealed significant features beneath the surface and also obtained the subsurface dielectric characteristics to constrain the composition of the materials. A 3-5 MHz global permittivity map has been derived from MARSIS data, providing insights into the physical properties within the first ∼60-80 m below the surface (Mouginot et al., 2012). The permittivity of the first few meters of the martian regolith calculated by the SHARAD surface echoes shows a significant correspondence with the geological dichotomy: high permittivity (7-10) on the highland side but lower (3-7) on the lowland side (Castaldo et al., 2017). The loss tangent value inferred from radar data has also been used to infer the possible presence of water ice (e.g., Campbell et al., 2021;Campbell & Morgan, 2018). Though the MARSIS and the SHARAD can detect the reflections on the surface and subsurface down to a depth of hundreds of meters, they have a limited ability to discriminate the presence of internal structures in the shallow subsurface regolith.