The Ekman spiral for piecewise-uniform viscosity Ocean Science DOI 10.5194/os-16-1089-2020 22 October 2020 Ekman’s (1905) solution for how wind affects ocean surface currents is revisited and extended analytically for a piecewise-constant profile of vertical diffusion. This allows a comprehensive understanding of how the surface current deflection angle relative to the wind direction varies with the profile of vertical diffusion. Read more
Impact of an educational program on earthquake awareness and preparedness in Nepal Geoscience Communication DOI 10.5194/gc-3-279-2020 22 October 2020 We study the impact of an educational seismology program on earthquake awareness and preparedness in Nepal. We see that educational activities implemented in schools are effective at raising awareness levels and in improving adaptive capacities and preparedness for future earthquakes. Knowledge also reached the broader community though social learning, leading to broadscale awareness. The result observed in this study is encouraging for the continuation and expansion of the program. Read more
ISMIP6 Antarctica: a multi-model ensemble of the Antarctic ice sheet evolution over the 21st century The Cryosphere DOI 10.5194/tc-14-3033-2020 20 October 2020 The Antarctic ice sheet has been losing mass over at least the past 3 decades in response to changes in atmospheric and oceanic conditions. This study presents an ensemble of model simulations of the Antarctic evolution over the 2015–2100 period based on various ice sheet models, climate forcings and emission scenarios. Results suggest that the West Antarctic ice sheet will continue losing a large amount of ice, while the East Antarctic ice sheet could experience increased snow accumulation. Read more
A protocol for calculating basal melt rates in the ISMIP6 Antarctic ice sheet projections The Cryosphere DOI 10.5194/tc-14-3111-2020 20 October 2020 To predict the future Antarctic contribution to sea level rise, we need to use ice sheet models. The Ice Sheet Model Intercomparison Project for AR6 (ISMIP6) builds an ensemble of ice sheet projections constrained by atmosphere and ocean projections from the 6th Coupled Model Intercomparison Project (CMIP6). In this work, we present and assess a method to derive ice shelf basal melting in ISMIP6 from the CMIP6 ocean outputs, and we give examples of projected melt rates. Read more
The making of the New European Wind Atlas – Part 1: Model sensitivity Geoscientific Model Development DOI 10.5194/gmd-13-5053-2020 16 October 2020 Wind energy resource assessment routinely uses numerical weather prediction model output. We describe the evaluation procedures used for picking the suitable blend of model setup and parameterizations for simulating European wind climatology with the WRF model. We assess the simulated winds against tall mast measurements using a suite of metrics, including the Earth Mover’s Distance, which diagnoses the performance of each ensemble member using the full wind speed and direction distribution. Read more
Review article: Hilbert problems for the climate sciences in the 21st century – 20 years later Nonlinear Processes in Geophysics DOI 10.5194/npg-27-429-2020 15 October 2020 The scientific questions posed by the climate sciences are central to socioeconomic concerns today. This paper revisits several crucial questions, starting with What can we predict beyond 1 week, for how long, and by what methods?, and ending with Can we achieve enlightened climate control of our planet by the end of the century? We review the progress in dealing with the nonlinearity and stochasticity of the Earth system and emphasize major strides in coupled climate–economy modeling. Read more
The future sea-level contribution of the Greenland ice sheet: a multi-model ensemble study of ISMIP6 The Cryosphere DOI 10.5194/tc-14-3071-2020 15 October 2020 In this paper we use a large ensemble of Greenland ice sheet models forced by six different global climate models to project ice sheet changes and sea-level rise contributions over the 21st century. The results for two different greenhouse gas concentration scenarios indicate that the Greenland ice sheet will continue to lose mass until 2100, with contributions to sea-level rise of 90 ± 50 mm and 32 ± 17 mm for the high (RCP8.5) and low (RCP2.6) scenario, respectively. Read more
In situ measurements of soil and plant water isotopes: a review of approaches, practical considerations and a vision for the future Hydrology and Earth System Sciences DOI 10.5194/hess-24-4413-2020 13 October 2020 Water isotopes are a scientific tool that can be used to identify sources of water and answer questions such as From which soil depths do plants take up water?, which are highly relevant under changing climatic conditions. In the past, the measurement of water isotopes required tremendous effort. In the last decade methods have advanced and can now be applied in the field. Herein, we review the current status of direct field measurements of water isotopes and discuss future applications. Read more
Storm tide amplification and habitat changes due to urbanization of a lagoonal estuary Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2415-2020 13 October 2020 The geometry of estuaries is often altered through dredging to make room for ships and with extensive landfill over wetlands to enable development. Here, we use historical maps to help create computational models of seawater flow around and into a lagoonal bay of New York City for the 1880s and 2010s. Our results show that these past man-made changes cause higher coastal storm tides and that they result specifically from deeper depths, expanded inlet width, and landfill. Read more
A 6-year lidar survey reveals enhanced rockwall retreat and modified rockfall magnitudes/frequencies in deglaciating cirques Earth Surface Dynamics DOI 10.5194/esurf-8-753-2020 8 October 2020 Rockfall size and frequency in two deglaciating cirques in the Central Alps, Austria, is analysed based on 6-year rockwall monitoring with terrestrial lidar (2011–2017). The erosion rates derived from this dataset are very high due to a frequent occurrence of large rockfalls in freshly deglaciated areas. The results obtained are important for rockfall hazard assessments, as, in rockwalls affected by glacier retreat, historical rockfall patterns are not good predictors of future events. Read more
Current glacier recession causes significant rockfall increase: the immediate paraglacial response of deglaciating cirque walls Earth Surface Dynamics DOI 10.5194/esurf-8-729-2020 8 October 2020 Climate warming is causing significant ice surface lowering even in the uppermost parts of alpine glaciers. Using terrestrial lidar, we quantify rockfall in freshly exposed cirque walls. During 6-year monitoring (2011–2017), an extensive dataset was established and over 600 rockfall events identified. Drastically increased rockfall activity following ice retreat can clearly be observed as 60 % of the rockfall volume detached from less than 10 m above the glacier surface. Read more
A Bayesian framework for emergent constraints: case studies of climate sensitivity with PMIP Climate of the Past DOI 10.5194/cp-16-1715-2020 6 October 2020 Interest in past climates as sources of information for the climate system has grown in recent years. In particular, studies of the warm mid-Pliocene and cold Last Glacial Maximum showed relationships between the tropical surface temperature of the Earth and its sensitivity to an abrupt doubling of atmospheric CO 2 . In this study, we develop a new and promising statistical method and obtain similar results as previously observed, wherein the sensitivity does not seem to exceed extreme values. Read more
Vertical profiles of light absorption and scattering associated with black carbon particle fractions in the springtime Arctic above 79∘ N Atmospheric Chemistry and Physics DOI 10.5194/acp-20-10545-2020 6 October 2020 Black carbon is a factor in the warming of the Arctic atmosphere due to its ability to absorb light, but the uncertainty is high and few observations have been made in the high Arctic above 80° N. We combine airborne and ground-based observations in the springtime Arctic, at and above 80° N, with simulations from a global model to show that light absorption by black carbon may be much larger than modelled. However, the uncertainty remains high. Read more
Comparing secondary organic aerosol (SOA) volatility distributions derived from isothermal SOA particle evaporation data and FIGAERO–CIMS measurements Atmospheric Chemistry and Physics DOI 10.5194/acp-20-10441-2020 1 October 2020 We compared the volatility distributions of secondary organic aerosol (SOA) constituents estimated from isothermal evaporation experiments from either particle size change data, by process modelling and global optimization, or from mass spectrometer data with positive matrix factorization analysis. Our results show that, despite the two very different estimation methods, the volatility distributions are comparable if uncertainties are taken into account. Read more
Predicting the morphology of ice particles in deep convection using the super-droplet method:development and evaluation of SCALE-SDM 0.2.5-2.2.0, -2.2.1, and -2.2.2 Geoscientific Model Development DOI 10.5194/gmd-13-4107-2020 1 October 2020 Using the super-droplet method, we constructed a detailed numerical model of mixed-phase clouds based on kinetic description and subsequently demonstrated that a large-eddy simulation of a cumulonimbus which predicts ice particle morphology without assuming ice categories or mass–dimension relationships is possible. Our results strongly support the particle-based modeling methodology’s efficacy for simulating mixed-phase clouds. Read more
A compact QCL spectrometer for mobile, high-precision methane sensing aboard drones Atmospheric Measurement Techniques DOI 10.5194/amt-13-4715-2020 29 September 2020 We describe a lightweight (2 kg) mid-IR laser spectrometer for airborne, in situ atmospheric methane (CH 4 ) measurements. The instrument, based on an open-path circular multipass cell, provides fast response (1 Hz) and sub-parts-per-billion precision. It can easily be mounted on a drone, giving access to highly resolved 4D (spatial and temporal) data. The performance was assessed during field deployments involving artificial CH 4 releases and vertical concentration gradients in the PBL. Read more
Using constructed soils for green infrastructure – challenges andlimitations SOIL DOI 10.5194/soil-6-413-2020 29 September 2020 The goal of this study was to discuss current methods to create soils adapted for various green infrastructure (GI) designs. Investigating these new soils for several design categories of GI will provide technical information for management and design agencies. Moreover, these studies can serve as pioneer experiments to prevent recurring errors and, thus, provide improved plant growth practices. Results show that these constructed soils have a high potential to provide multiple soil functions. Read more
HyLands 1.0: a hybrid landscape evolution model to simulate the impact of landslides and landslide-derived sediment on landscape evolution Geoscientific Model Development DOI 10.5194/gmd-13-3863-2020 24 September 2020 Landslides shape the Earth’s surface and are a dominant source of terrestrial sediment. Rivers, then, act as conveyor belts evacuating landslide-produced sediment. Understanding the interaction among rivers and landslides is important to predict the Earth’s surface response to past and future environmental changes and for mitigating natural hazards. We develop HyLands, a new numerical model that provides a toolbox to explore how landslides and rivers interact over several timescales. Read more
Quantifying burning efficiency in megacities using the NO2/CO ratio fromthe Tropospheric Monitoring Instrument (TROPOMI) Atmospheric Chemistry and Physics DOI 10.5194/acp-20-10295-2020 24 September 2020 Rapid urbanization has increased the consumption of fossil fuel, contributing the degradation of urban air quality. Burning efficiency is a major factor determining the impact of fuel burning on the environment. We quantify the burning efficiency of fossil fuel use over six megacities using satellite remote sensing data. City governance can use these results to understand air pollution scenarios and to formulate effective air pollution control strategies. Read more
Fire Weather Index: the skill provided by the European Centre for Medium-Range Weather Forecasts ensemble prediction system Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2365-2020 22 September 2020 Forecasting of daily fire weather indices driven by the ECMWF ensemble prediction system is shown to have a good skill up to 10 d ahead in predicting flammable conditions in most regions of the world. The availability of these forecasts through the Copernicus Emergency Management Service can extend early warnings by up to 1–2 weeks, allowing for greater proactive coordination of resource-sharing and mobilization within and across countries. Read more