Highlight articles

The Making of the New European Wind Atlas – Part 2: Production and evaluation

This is the second of two papers that document the creation of the New European Wind Atlas (NEWA). The paper includes a detailed description of the technical and practical aspects that went into running the mesoscale simulations and the microscale downscaling for generating the climatology. A comprehensive evaluation of each component of the NEWA model chain is presented using observations from a large set of tall masts located all over Europe.

Topographic controls on divide migration, stream capture, anddiversification in riverine life

Organisms evolve in ever-changing environments under complex process interactions. We applied a new software modelling tool to assess how changes in river course impact the evolution of riverine species. Models illustrate the climatically and tectonically forced landscape changes that can drive riverine biodiversity, especially where topographic relief is low. This research demonstrates that river course changes can contribute to the high riverine biodiversity found in real-world lowland basins.

Impact of horizontal resolution on global ocean–sea ice model simulationsbased on the experimental protocols of the Ocean Model IntercomparisonProject phase 2 (OMIP-2)

This paper presents global comparisons of fundamental global climate variables from a suite of four pairs of matched low- and high-resolution ocean and sea ice simulations to assess the robustness of climate-relevant improvements in ocean simulations associated with moving from coarse (∼1°) to eddy-resolving (∼0.1°) horizontal resolutions. Despite significant improvements, greatly enhanced horizontal resolution does not deliver unambiguous bias reduction in all regions for all models.

Dominant process zones in a mixed fluvial–tidal delta are morphologically distinct

We propose a machine learning approach for the classification and analysis of large delta systems. The approach uses remotely sensed data, channel network extraction, and the analysis of 10 metrics to identify clusters of islands with similar characteristics. The 12 clusters are grouped in six main classes related to morphological processes acting on the system. The approach allows us to identify spatial patterns in large river deltas to inform modeling and the collection of field observations.

Timing of exotic, far-traveled boulder emplacement and paleo-outburstflooding in the central Himalayas

Large boulders found in two Himalayan valleys show signs of long fluvial transport (>10 km). Paleo-discharges required to mobilize these boulders exceed typical monsoon discharges. Exposure dating shows that a cluster of these boulders was emplaced ca. 5 kyr ago. This period is coeval with a weakening of the Indian monsoon and glacier retreat in the area. We, therefore, suggest that glacier lake outburst floods are likely mechanisms that can explain these exceptional transport processes.

An improved mechanistic model for ammonia volatilization in Earth system models: Flow of Agricultural Nitrogen version 2 (FANv2)

Mostly emitted by the agricultural sector, ammonia has an important role in atmospheric chemistry. We developed a model to simulate how ammonia emissions respond to changes in temperature and soil moisture, and we evaluated agricultural ammonia emissions globally. The simulated emissions agree with earlier estimates over many regions, but the results highlight the variability of ammonia emissions and suggest that emissions in warm climates may be higher than previously thought.

The making of the New European Wind Atlas – Part 1: Model sensitivity

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.

A 6-year lidar survey reveals enhanced rockwall retreat and modified rockfall magnitudes/frequencies in deglaciating cirques

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.

Current glacier recession causes significant rockfall increase: the immediate paraglacial response of deglaciating cirque walls

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.

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

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.

GM Geomorphology Highlight articles

Highlight articles

The Making of the New European Wind Atlas – Part 2: Production and evaluation

Topographic controls on divide migration, stream capture, anddiversification in riverine life

Impact of horizontal resolution on global ocean–sea ice model simulationsbased on the experimental protocols of the Ocean Model IntercomparisonProject phase 2 (OMIP-2)

Dominant process zones in a mixed fluvial–tidal delta are morphologically distinct

Timing of exotic, far-traveled boulder emplacement and paleo-outburstflooding in the central Himalayas

An improved mechanistic model for ammonia volatilization in Earth system models: Flow of Agricultural Nitrogen version 2 (FANv2)

The making of the New European Wind Atlas – Part 1: Model sensitivity

A 6-year lidar survey reveals enhanced rockwall retreat and modified rockfall magnitudes/frequencies in deglaciating cirques

Current glacier recession causes significant rockfall increase: the immediate paraglacial response of deglaciating cirque walls

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

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