Leto Mission Concept for Green Reconnaissance of the Marius Hills Lunar Pit

Lava tubes are potentially important sites for the long-term human presence on the Moon because they provide shelter from surface hazards, including micrometeorites, radiation, extreme temperatures, and dust. The discovery of a lava tube opening or pit at Marius Hills in Oceanus Procellarum is compelling motivation for robotic and eventually human exploration missions to these sites for in situ investigations and site assessments to determine viability for habitation and utilization of lunar resources. We make the case for Marius Hills to be a high-priority landing site and present elements of lunar data analysis, instrument/payload concepts, science justification for robotic missions, and thematic geologic reconnaissance and remote sensing that should be conducted prior to any construction or emplacement of infrastructure. This is described as a “green reconnaissance” approach to lunar exploration and exploitation, which seeks to address such contamination factors as sprayed rocket exhaust and sublimating water in order to preserve science fidelity. We are developing a concept of operations called the Leto mission for a green reconnaissance approach to robotically access the Marius Hills sublunarean void

Ice wedge degradation: Why Arctic lowlands are becoming wetter and drier

Top melting of ice-wedges and subsequent ground subsidence is now a widespread phenomenon across the Arctic domain. We show field and remote sensing observations that document extensive ice-wedge degradation, which initially has resulted in increased wetness contrast across the landscape (i.e. both a drying and a wetting), a shift in pond type and an overall drying in later stages. The differential ground subsidence at cold continuous permafrost regions appear to be linked to press and pulse climate forcing. Here, the process of crossing the local threshold for ice-wedge stability may be favored by a press occurrence such as long-term, gradual increases in summer air temperature, mean annual air temperature and/or possibly winter precipitation, but our observations suggest it is most likely initiated by pulse atmospheric forcing such as extreme summer warmth and/or winter precipitation. Field measurements of water levels, frost tables and snow accumulation across the main ice-wedge polygon types and their respective features support dramatic shifts in the hydrologic regime with altered topography and a complexity that ultimately affect the larger-scale hydrologic system. For example, our numerical model experiments show that a connected trough-network reduces inundation and increases runoff and that changing patterns of snow distribution due to the differential ground subsidence play a crucial role in altering lowland tundra water balance. These fine-scale (10’s cm) geomorphic changes are expected to further expand and amplify in rapidly warming permafrost regions and likely will dramatically modify land-atmosphere and land-ocean fluxes and exchange of carbon, water, and energy

Fine-Scale Monitoring of Long-term Wetland Loss Using LiDAR Data and Historical Aerial Photographs the Example of the Couesnon Floodplain, France

International audienceWetland area has decreased in most parts of the world and remains threatened by human pressures. However, wetland loss is difficult to accurately detect, delineate and quantify. While wetland distribution is influenced mainly by landform, LiDAR data provide accurate digital elevation models that can be used to delineate wetlands. Our objective was to map wetland loss at a fine-scale using LiDAR data and historical aerial photographs based on a functional typology that identifies potential, existing and efficient wetlands. The study focused on a 132 km(2) site with valley bottom wetlands located in western France. Boundaries of potential wetlands were extracted from a LiDAR-derived Digital Terrain Model that was standardized according to channel network elevation. We identified existing wetlands using interpretation of aerial photographs acquired in 1952, 1978 and 2012. We used multiple correspondence analysis to identify different types of wetland loss. Results show that potential wetlands were successfully delineated at 15000 (88-90% overall accuracy) and that 14% of existing wetland area was lost. This highlights the importance of identifying "negotiation areas" where wetland restoration is a priority. The results also reveal two main types of wetland loss based on area, geomorphic context, land cover and period of loss