Escarpment retreat rates derived from detrital cosmogenic nuclide concentrations Earth Surface Dynamics DOI 10.5194/esurf-9-1301-2021 26 November 2021 Although great escarpment mountain ranges are characterized by high relief, modern erosion rates suggest slow rates of landscape change. We question this interpretation by presenting a new method for interpreting concentrations of cosmogenic isotopes. Our analysis shows that erosion has localized onto an escarpment face, driving retreat of the escarpment at high rates. Our quantification of this retreat rate rationalizes the high-relief, dramatic landscape with the rates of geomorphic change. Read more
A dynamically based method for estimating the Atlantic meridional overturning circulation at 26° N from satellite altimetry Ocean Science DOI 10.5194/os-17-1321-2021 24 November 2021 In the North Atlantic, ocean currents carry warm surface waters northward and return cooler deep waters southward. This type of ocean circulation, known as overturning, is important for the Earth’s climate. This overturning has been measured using a mooring array at 26° N in the North Atlantic since 2004. Here we use these mooring data and global satellite data to produce a new method for monitoring the overturning over longer timescales, which could potentially be applied to different latitudes. Read more
Persistent impacts of the 2018 drought on forest disturbance regimes in Europe Biogeosciences DOI 10.5194/bg-18-5223-2021 22 November 2021 Europe was affected by an extreme drought in 2018. We show that this drought has increased forest disturbances across Europe, especially central and eastern Europe. Disturbance levels observed 2018–2020 were the highest on record for 30 years. Increased forest disturbances were correlated with low moisture and high atmospheric water demand. The unprecedented impacts of the 2018 drought on forest disturbances demonstrate an urgent need to adapt Europe’s forests to a hotter and drier future. Read more
The driving factors of new particle formation and growth in the polluted boundary layer Atmospheric Chemistry and Physics DOI 10.5194/acp-21-14275-2021 19 November 2021 Experiments at CLOUD show that in polluted environments new particle formation (NPF) is largely driven by the formation of sulfuric acid–base clusters, stabilized by amines, high ammonia concentrations or lower temperatures. While oxidation products of aromatics can nucleate, they play a minor role in urban NPF. Our experiments span 4 orders of magnitude variation of observed NPF rates in ambient conditions. We provide a framework based on NPF and growth rates to interpret ambient observations. Read more
Giant ice rings in southern Baikal: multi-satellite data help to study ice cover dynamics and eddies under ice The Cryosphere DOI 10.5194/tc-15-4501-2021 17 November 2021 Giant ice rings are a beautiful and puzzling natural phenomenon. Our data show that ice rings are generated by lens-like warm eddies below the ice. We use multi-satellite data to analyse lake ice cover in the presence of eddies in April 2020 in southern Baikal. Unusual changes in ice colour may be explained by the competing influences of atmosphere above and the warm eddy below the ice. Tracking ice floes also helps to estimate eddy currents and their influence on the upper water layer. Read more
Stalagmite carbon isotopes suggest deglacial increase in soil respiration in western Europe driven by temperature change Climate of the Past DOI 10.5194/cp-17-1903-2021 15 November 2021 Soil respiration is a critical but poorly constrained component of the global carbon cycle. We analyse the effect of changing soil respiration rates on the stable carbon isotope ratio of speleothems from northern Spain covering the last deglaciation. Using geochemical analysis and forward modelling we quantify the processes affecting speleothem stable carbon isotope ratios and extract a signature of increasing soil respiration synchronous with deglacial warming. Read more
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