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Earth Surface Dynamics

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.


Biogeosciences

Increase in ocean acidity variability and extremes under increasing atmospheric CO2

Ensemble simulations of an Earth system model reveal that ocean acidity extremes have increased in the past few decades and are projected to increase further in terms of frequency, intensity, duration, and volume extent. The increase is not only caused by the long-term ocean acidification due to the uptake of anthropogenic CO 2 , but also due to changes in short-term variability. The increase in ocean acidity extremes may enhance the risk of detrimental impacts on marine organisms.


Earth Surface Dynamics

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.


Geoscientific Model Development

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.


Latest posts from EGU blogs

GeoRoundup: the highlights of EGU Journals published during October!

GeoRoundup: the highlights of EGU Journals published during October!

Each month we feature specific Divisions of EGU and during the monthly GeoRoundup we will be putting the journals that publish science from those Divisions at the top of the Highlights roundup. For October, the Divisions we are featuring are: Natural Hazards (NH), Hydrological Sciences (HS) and Seismology (SM). They are served by the journals: Geoscientific Model Development (GMD), Hydrology and Earth System Sciences (HESS), Natural Hazards and Earth System Sciences (NHESS), SOIL, and Solid Earth (SE). Featured highlights Geoscientific …


What can we learn from geodynamic failure?

What can we learn from geodynamic failure?

In this week’s post, Mohamed Gouiza discusses the challenges of living under constant stress, paralysed by the possibility of failure and self-perceived inevitability of impending breakup. Continental rifting, of course! Oh… did you think I was talking about life as a researcher? Under tensile stress, the lithosphere stretches, the asthenosphere rises, the crust fails, and rifts form. During this process, heat flow increases, melting by decompression can occur, and igneous material is either emplaced at depth or finds its way …


Featured catchment: Water Towers of Mesopotamia: Snow feeding the cultural heritage

Featured catchment: Water Towers of Mesopotamia: Snow feeding the cultural heritage

Importance and challenges of snow modelling in Turkey Snow and glaciers in the high mountains play a crucial role for 1.6 billion people living downstream of mountainous areas. Thus, understanding snow dynamics is crucial for downstream irrigation, hydropower, flood control etc. In eastern Anatolia, Turkey (the mean elevation is around 1140 m), much of the precipitation falls as snow and is retained on the ground for more than half of the year especially in the mountainous regions. Although snow hydrology …