Combined use of Mie–Raman and fluorescence lidar observations for improving aerosol characterization: feasibility experiment Atmospheric Measurement Techniques DOI 10.5194/amt-13-6691-2020 6 January 2021 To study the feasibility of a fluorescence lidar for aerosol characterization, the fluorescence channel is added to the multiwavelength Mie-Raman lidar of Lille University. A part of the fluorescence spectrum is selected by the interference filter of 44 nm bandwidth centered at 466 nm. Such an approach has demonstrated high sensitivity, allowing fluorescence signals from weak aerosol layers to be detected. The technique can also be used for monitoring the aerosol inside the cloud layers. Read more
The dual-field-of-view polarization lidar technique: a new concept in monitoring aerosol effects in liquid-water clouds – theoretical framework Atmospheric Chemistry and Physics DOI 10.5194/acp-20-15247-2020 5 January 2021 A novel lidar method to study cloud microphysical properties (of liquid water clouds) and to study aerosol–cloud interaction (ACI) is developed and presented in this paper. In Part 1, the theoretical framework including an error analysis is given together with an overview of the aerosol information that the same lidar system can obtain. The ACI concept based on aerosol and cloud information is also explained. Applications of the proposed approach to lidar measurements are presented in Part 2. Read more
Evolution of events before and after the 17 June 2017 rock avalanche at Karrat Fjord, West Greenland – a multidisciplinary approach to detecting andlocating unstable rock slopes in a remote Arctic area Earth Surface Dynamics DOI 10.5194/esurf-8-1021-2020 4 January 2021 The 17 June 2017 Karrat landslide in Greenland caused a tsunami that killed four people. We apply a multidisciplinary workflow to reconstruct a timeline of events and find that three historic landslides occurred in 2009, 2016, and 2017. We also find evidence of much older periods of landslide activity. Three newly discovered active slopes might pose a future hazard. We speculate that the trigger for the recent events is melting permafrost due to a warming climate. Read more
Iron and aluminum association with microbially processed organic matter viameso-density aggregate formation across soils: organo-metallic gluehypothesis SOIL DOI 10.5194/soil-6-597-2020 1 January 2021 Global significance of metals (extractable Fe and Al phases) to control organic matter (OM) in recognized. Next key questions include the identification of their localization and mechanism behind OM–metal relationships. Across 23 soils of contrasting mineralogy, Fe and Al phases were mainly associated with microbially processed OM as meso-density microaggregates. OM- and metal-rich nanocomposites with a narrow OM : metal ratio likely acted as binding agents. A new conceptual model was proposed. Read more
The Antarctic sea ice cover from ICESat-2 and CryoSat-2: freeboard, snow depth, and ice thickness The Cryosphere DOI 10.5194/tc-14-4453-2020 31 December 2020 Our current understanding of Antarctic ice cover is largely informed by ice extent measurements from passive microwave sensors. These records, while useful, provide a limited picture of how the ice is responding to climate change. In this paper, we combine measurements from ICESat-2 and CryoSat-2 missions to assess snow depth and ice thickness of the Antarctic ice cover over an 8-month period (April through November 2019). The potential impact of salinity in the snow layer is discussed. Read more
The catastrophic thermokarst lake drainage events of 2018 in northwesternAlaska: fast-forward into the future The Cryosphere DOI 10.5194/tc-14-4279-2020 30 December 2020 In summer 2018, northwestern Alaska was affected by widespread lake drainage which strongly exceeded previous observations. We analyzed the spatial and temporal patterns with remote sensing observations, weather data and lake-ice simulations. The preceding fall and winter season was the second warmest and wettest on record, causing the destabilization of permafrost and elevated water levels which likely led to widespread and rapid lake drainage during or right after ice breaku Read more
Focus on glaciers: a geo-photo exposition of vanishing beauty Geoscience Communication DOI 10.5194/gc-3-381-2020 29 December 2020 We organized an exhibition on the climate crisis using high-quality images shot by scientists, who are amateur photographers, during their campaigns in glacier regions. Working-age people, attracted by the gorgeous images, received the message that such beauty is in danger of vanishing. Twice, the visitors could talk directly with the experts to discuss geoscience, photography, and aesthetic choices and, of course, climate change, a problem that each of us has to play a part in to solve. Read more
Investigating the sensitivity of soil heterotrophic respiration to recent snow cover changes in Alaska using a satellite-based permafrost carbon model Biogeosciences DOI 10.5194/bg-17-5861-2020 28 December 2020 We developed a 1 km satellite-data-driven permafrost carbon model to evaluate soil respiration sensitivity to recent snow cover changes in Alaska. Results show earlier snowmelt enhances growing-season soil respiration and reduces annual carbon uptake, while early cold-season soil respiration is linked to the number of snow-free days after the land surface freezes. Our results also show nonnegligible influences of subgrid variability in surface conditions on model-simulated CO 2 seasonal cycles. Read more
A systematic exploration of satellite radar coherence methods for rapid landslide detection Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-3197-2020 25 December 2020 Satellite radar could provide information on landslide locations within days of an earthquake or rainfall event anywhere on Earth, but until now there has been a lack of systematic testing of possible radar methods, and most methods have been demonstrated using a single case study event and data from a single satellite sensor. Here we test five methods on four events, demonstrating their wide applicability and making recommendations on when different methods should be applied in the future. Read more
New flood frequency estimates for the largest river in Norway based on the combination of short and long time series Hydrology and Earth System Sciences DOI 10.5194/hess-24-5595-2020 24 December 2020 We combine systematic, historical, and paleo information to obtain flood information from the last 10 300 years for the Glomma River in Norway. We identify periods with increased flood activity (4000–2000 years ago and the recent 1000 years) that correspond broadly to periods with low summer temperatures and glacier growth. The design floods in Glomma were more than 20 % higher during the 18th century than today. We suggest that trends in flood variability are linked to snow in late spring. Read more
