Relative humidity gradients as a key constraint on terrestrial water and energy fluxes Hydrology and Earth System Sciences DOI 10.5194/hess-25-5175-2021 12 November 2021 Here, we present a novel physically based evaporation model to demonstrate that vertical relative humidity (RH) gradients from the land surface to the atmosphere tend to evolve towards zero due to land–atmosphere equilibration processes. Collapsing RH gradients on daily to yearly timescales indicate an emergent land–atmosphere equilibrium, making it possible to determine evapotranspiration using only meteorological information, independent of land surface conditions and vegetation controls. Read more
Enhanced moisture delivery into Victoria Land, East Antarctica, during the early Last Interglacial: implications for West Antarctic Ice Sheet stability Climate of the Past DOI 10.5194/cp-17-1841-2021 10 November 2021 Here we reconstruct the rate of snow accumulation during the Last Interglacial period in an East Antarctic ice core located near the present-day northern edge of the Ross Ice Shelf. We find an order-of-magnitude increase in the accumulation rate during the peak warming in the Last Interglacial. This large increase in mass accumulation is compatible with less ice cover in the Ross Sea, perhaps created by a partly collapsed West Antarctic Ice Sheet, whose stability in a warming world is uncertain. Read more
Landslide-lake outburst floods accelerate downstream hillslope slippage Earth Surface Dynamics DOI 10.5194/esurf-9-1251-2021 8 November 2021 The eastern Tibetan Plateau is an ideal place to study interactions among different geomorphic drivers. We report the impacts of two 2018 landslide-lake outburst floods up to 100 km distance downstream of the Jinsha River. By using remote sensing images, we found that the 2018 floods caused many hillslopes to slump during the prolonged period afterwards. The finding could help us to obtain a holistic picture of LLF impacts and improve geomorphic models of landscape evolution. Read more
Soil greenhouse gas fluxes from tropical coastal wetlands and alternative agricultural land uses Biogeosciences DOI 10.5194/bg-18-5085-2021 5 November 2021 Greenhouse gas emissions were measured and compared from natural coastal wetlands and their converted agricultural lands across annual seasonal cycles in tropical Australia. Ponded pastures emitted ~ 200-fold-higher methane than any other tested land use type, suggesting the highest greenhouse gas mitigation potential and financial incentives by the restoration of ponded pastures to natural coastal wetlands. Read more
Heterogeneity and chemical reactivity of the remote troposphere defined by aircraft measurements Atmospheric Chemistry and Physics DOI 10.5194/acp-21-13729-2021 3 November 2021 The NASA Atmospheric Tomography (ATom) mission built a climatology of the chemical composition of tropospheric air parcels throughout the middle of the Pacific and Atlantic oceans. The level of detail allows us to reconstruct the photochemical budgets of O3 and CH4 over these vast, remote regions. We find that most of the chemical heterogeneity is captured at the resolution used in current global chemistry models and that the majority of reactivity occurs in the “hottest” 20 % of parcels. Read more
Deformation-enhanced diagenesis and bacterial proliferation in the Nankai accretionary prism Solid Earth DOI 10.5194/se-12-2067-2021 1 November 2021 Sediments accumulated in accretionary prisms are deformed by the compression imposed by plate subduction. Here we show that deformation of the sediments transforms some minerals in them. We suggest that these mineral transformations are due to the proliferation of microorganisms boosted by deformation. Deformation-enhanced microbial proliferation may change our view of sedimentary and tectonic processes in subduction zones. Read more
Geochemical consequences of oxygen diffusion from the oceanic crust into overlying sediments and its significance for biogeochemical cycles based on sediments of the northeast Pacific Biogeosciences DOI 10.5194/bg-18-4965-2021 29 October 2021 Oxygen penetrates sediments not only from the ocean bottom waters but also from the basement. The impact of the latter is poorly understood. We show that this basement oxygen has a clear impact on the nitrogen cycle, the redox state, and the distribution of manganese, nickel cobalt and organic matter in the sediments. This is important for (1) global biogeochemical cycles, (2) understanding sedimentary life and (3) the interpretation of the sediment record to reconstruct the past. Read more
Wildfire smoke, Arctic haze, and aerosol effects on mixed-phase and cirrus clouds over the North Pole region during MOSAiC: an introduction Atmospheric Chemistry and Physics DOI 10.5194/acp-21-13397-2021 27 October 2021 A Raman lidar was operated aboard the icebreaker Polarstern during MOSAiC and monitored aerosol and cloud layers in the central Arctic up to 30 km height. The article provides an overview of the spectrum of aerosol profiling observations and shows aerosol–cloud interaction studies for liquid-water and ice clouds. A highlight was the detection of a 10 km deep wildfire smoke layer over the North Pole up to 17 km height from the fire season of 2019, which persisted over the whole winter period. Read more
Rheological stratification in impure rock salt during long-term creep: morphology, microstructure, and numerical models of multilayer folds in the Ocnele Mari salt mine, Romania Solid Earth DOI 10.5194/se-12-2041-2021 25 October 2021 We analyse folded multilayer sequences in the Ocnele Mari salt mine (Romania) to gain insight into the long-term rheological behaviour of rock salt. Our results indicate the large role of even a small number of impurities in the rock salt for its effective mechanical behaviour. We demonstrate how the development of folds that occur at various scales can be used to constrain the viscosity ratio in the deformed multilayer sequence. Read more
Predicting gas–particle partitioning coefficients of atmospheric molecules with machine learning Atmospheric Chemistry and Physics DOI 10.5194/acp-21-13227-2021 22 October 2021 The study of climate change relies on climate models, which require an understanding of aerosol formation. We train a machine-learning model to predict the partitioning coefficients of atmospheric molecules, which govern condensation into aerosols. The model can make instant predictions based on molecular structures with accuracy surpassing that of standard computational methods. This will allow the screening of low-volatility molecules that contribute most to aerosol formation. Read more
