Medusa–Aqua system: simultaneous measurement and evaluation of novel potential halogenated transient tracers HCFCs, HFCs, and PFCs in the ocean Ocean Science DOI 10.5194/os-17-509-2021 21 May 2021 Observations of transient tracer distribution provide essential information on ocean ventilation. The use of several commonly used transient traces is limited as their atmospheric mole fractions do not monotonically change. Here we explore new potential oceanic transient tracers with an analytical system that simultaneously measures a large range of compounds. Combined with the known atmospheric history and seawater solubility, we discuss the utility of selected HCFCs, HFCs, and PFCs as tracers. HCFCs, HFCs, and PFCs in the ocean">Read more
Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada – Part 2: Future change in cryosphere, vegetation, and hydrology Hydrology and Earth System Sciences DOI 10.5194/hess-25-1849-2021 19 May 2021 This article examines future changes in land cover and hydrological cycling across the interior of western Canada under climate conditions projected for the 21st century. Key insights into the mechanisms and interactions of Earth system and hydrological process responses are presented, and this understanding is used together with model application to provide a synthesis of future change. This has allowed more scientifically informed projections than have hitherto been available. CCRN) research in the interior of western Canada – Part 2: Future change in cryosphere, vegetation, and hydrology">Read more
Arctic Ocean acidification over the 21st century co-driven by anthropogenic carbon increases and freshening in the CMIP6 model ensemble Biogeosciences DOI 10.5194/bg-18-2221-2021 17 May 2021 The uptake of carbon, emitted as a result of human activities, results in ocean acidification. We analyse 21st-century projections of acidification in the Arctic Ocean, a region of particular vulnerability, using the latest generation of Earth system models. In this new generation of models there is a large decrease in the uncertainty associated with projections of Arctic Ocean acidification, with freshening playing a greater role in driving acidification than previously simulated. Read more
Airborne measurements of oxygen concentration from the surface to the lower stratosphere and pole to pole Atmospheric Measurement Techniques DOI 10.5194/amt-14-2543-2021 14 May 2021 We describe methods used to make high-precision global-scale airborne measurements of atmospheric oxygen concentrations over a period of 20 years in order to study the global carbon cycle. Our techniques include an in situ vacuum ultraviolet absorption instrument and a pressure- and flow-controlled, cryogenically dried, glass flask sampler. We have deployed these instruments in 15 airborne research campaigns spanning from the Earth’s surface to the lower stratosphere and from pole to pole. Read more
Evaluating stratospheric ozone and water vapour changes in CMIP6 models from 1850 to 2100 Atmospheric Chemistry and Physics DOI 10.5194/acp-21-5015-2021 12 May 2021 Stratospheric ozone and water vapour are key components of the Earth system; changes to both have important impacts on global and regional climate. We evaluate changes to these species from 1850 to 2100 in the new generation of CMIP6 models. There is good agreement between the multi-model mean and observations, although there is substantial variation between the individual models. The future evolution of both ozone and water vapour is strongly dependent on the assumed future emissions scenario. Read more
Diverging land-use projections cause large variability in their impacts on ecosystems and related indicators for ecosystem services Earth System Dynamics DOI 10.5194/esd-12-327-2021 10 May 2021 Many projections of future land-use/-cover exist. We evaluate a number of these and determine the variability they cause in ecosystems and their services. We found that projections differ a lot in regional patterns, with some patterns being at least questionable in a historical context. Across ecosystem service indicators, resulting variability until 2040 was highest in crop production. Results emphasize that such variability should be acknowledged in assessments of future ecosystem provisions. Read more
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. ICAR) 1.0.1">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. CAPE (convective available potential energy) summer convection in large-domain large-eddy simulations with ICON">Read more