How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region Weather and Climate Dynamics DOI 10.5194/wcd-2-281-2021 7 May 2021 The interaction of clouds in the trade wind region with the atmospheric flow is complex and at the heart of uncertainties associated with climate projections. In this study, a natural tracer of atmospheric circulation is used to establish a link between air originating from dry regions of the midlatitudes and the occurrence of specific cloud patterns. Two pathways involving transport within midlatitude weather systems are identified, by which air is brought into the trades within 5–10 d. Read more
A process-based evaluation of the Intermediate Complexity Atmospheric Research Model (ICAR) 1.0.1 Geoscientific Model Development DOI 10.5194/gmd-14-1657-2021 3 May 2021 This study conducts an in-depth process-based evaluation of the Intermediate Complexity Atmospheric Research (ICAR) model, employing idealized simulations to increase the understanding of the model and develop recommendations to maximize the probability that its results are correct for the right reasons. The results show that when model skill is evaluated from statistical metrics based on comparisons to surface observations only, such an analysis may not reflect the skill of the model in capturing atmospheric processes like gravity waves and cloud formation. Read more
Similar importance of edaphic and climatic factors for controlling soil organic carbon stocks of the world Biogeosciences DOI 10.5194/bg-18-2063-2021 30 April 2021 Soil organic carbon (SOC) accounts for two-thirds of terrestrial carbon. Yet, the role of soil physicochemical properties in regulating SOC stocks is unclear, inhibiting reliable SOC predictions under land use and climatic changes. Using legacy observations from 141 584 soil profiles worldwide, we disentangle the effects of biotic, climatic and edaphic factors (a total of 31 variables) on the global spatial distribution of SOC stocks in four sequential soil layers down to 2 m. Read more
The behavior of high-CAPE (convective available potential energy) summer convection in large-domain large-eddy simulations with ICON Atmospheric Chemistry and Physics DOI 10.5194/acp-21-4285-2021 28 April 2021 Current state-of-the-art regional numerical weather prediction (NWP) models employ kilometer-scale horizontal grid resolutions, thereby simulating convection within the grey zone. Increasing resolution leads to resolving the 3D motion field and has been shown to improve the representation of clouds and precipitation. Using a hectometer-scale model in forecasting mode on a large domain therefore offers a chance to study processes that require the simulation of the 3D motion field at small horizontal scales. Read more
Do small and large floods have the same drivers of change? A regional attribution analysis in Europe Hydrology and Earth System Sciences DOI 10.5194/hess-25-1347-2021 26 April 2021 Recent studies have shown evidence of increasing and decreasing trends for average floods and flood quantiles across Europe. Studies attributing observed changes in flood peaks to their drivers have mostly focused on the average flood behaviour, without distinguishing small and large floods. This paper proposes a new framework for attributing flood changes to potential drivers, as a function of return period (T), in a regional context. Read more
Interhemispheric transport of metallic ions within ionospheric sporadic E layers by the lower thermospheric meridional circulation Atmospheric Chemistry and Physics DOI 10.5194/acp-21-4219-2021 23 April 2021 Here, we report a study of ionospheric irregularities using scintillation data from COSMIC satellites and identify a large-scale horizontal transport of long-lived metallic ions, combining the simulations of the Whole Atmosphere Community Climate Model with the chemistry of metals and ground-based observations from two meridional chains of stations from 1975–2016. Read more
Observed snow depth trends in the European Alps: 1971 to 2019 The Cryosphere DOI 10.5194/tc-15-1343-2021 9 April 2021 Here, we present an Alpine-wide analysis of snow depth from six Alpine countries – Austria, France, Germany, Italy, Slovenia, and Switzerland – including altogether more than 2000 stations of which more than 800 were used for the trend assessment. Linear trends of monthly mean snow depth between1971 and 2019 showed decreases in snow depth for most stations from November to May. Read more
The enigma of relict large sorted stone stripes in the tropical Ethiopian Highlands Earth Surface Dynamics DOI 10.5194/esurf-9-145-2021 7 April 2021 Large forms of sorted patterned ground belong to the most prominent geomorphic features of periglacial and permafrost environments of the mid-latitudes and polar regions, but they were hitherto unknown in the tropics. Here, we report on relict large sorted stone stripes (up to 1000 m long, 15 m wide, and 2 m deep) on the ca. 4000 m high central Sanetti Plateau of the tropical Bale Mountains in the southern Ethiopian Highlands. Read more
geoChronR – an R package to model, analyze, and visualize age-uncertain data Geochronology DOI 10.5194/gchron-3-149-2021 5 April 2021 Chronological uncertainty is a hallmark of the paleoenvironmental sciences and geosciences. While many tools have been made available to researchers to quantify age uncertainties suitable for various settings and assumptions, disparate tools and output formats often discourage integrative approaches. Here, we describe geoChronR, an open-source R package to facilitate these tasks. Read more
Sensitivities to biological aerosol particle properties and ageing processes: potential implications for aerosol–cloud interactions and optical properties Atmospheric Chemistry and Physics DOI 10.5194/acp-21-3699-2021 2 April 2021 Primary biological aerosol particles (PBAPs), such as bacteria, viruses, fungi, and pollen, represent a small fraction of the total aerosol burden. Given that PBAPs are highly efficient atmospheric ice nuclei (IN) at T > -10 ∘C, we suggest that small changes in their sizes or surface properties due to chemical, physical, or biological processing might translate into large impacts on ice initiation in clouds. Read more