Glacial CO2 decrease and deep-water deoxygenation by iron fertilization from glaciogenic dust Climate of the Past DOI 10.5194/cp-15-981-2019 4 June 2019 Proxy records of glacial oxygen change provide constraints on the contribution of the biological pump to glacial CO2 decrease. Here, we report our numerical simulation which successfully reproduces records of glacial oxygen changes and shows the significance of iron supply from glaciogenic dust. Our model simulations clarify that the enhanced efficiency of the biological pump is responsible for glacial CO2 decline of more than 30 ppm and approximately half of deep-ocean deoxygenation. Read more
Telling the boiling frog what he needs to know: why climate change risks should be plotted as probability over time Geoscience Communication DOI 10.5194/gc-2-95-2019 29 May 2019 Humanity’s situation with respect to climate change is sometimes likened to that of a frog in a slow-boiling pot of water. But are we telling the frog what he needs to know? Most climate science is communicated to governments in the form of predictions of what is most likely to happen. I argue it should instead answer the following questions: what is the worst that could happen, and how likely will that become as time goes by? The risks and need to act will then become much clearer to see. Read more
Impacts of Three Gorges Dam’s operation on spatial–temporal patterns of tide–river dynamics in the Yangtze River estuary, China Ocean Science DOI 10.5194/os-15-583-2019 28 May 2019 In this study, we assessed the impacts of the world’s largest dam, the Three Gorges Dam (TGD), on tide–river dynamics and concluded that the strongest impacts occurred during autumn and winter due to the TGD’s operation. The results obtained will hopefully enhance our understanding of the impacts of large-scale human interventions on estuarine hydrodynamics and guide effective and sustainable water management in the Yangtze River estuary and other estuaries with substantial freshwater discharge. Read more
Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear The Cryosphere DOI 10.5194/tc-13-1495-2019 27 May 2019 Ice mechanics is an important tool to better predict the response of glaciers or polar ice sheets to climate variations. Nevertheless our current predictive abilities are limited as the microscale mechanisms responsible for ice creep are poorly identified. We show in this study, using state-of-the-art experimental techniques, which recrystallization processes control ice deformation. This will allow realistic simulations, necessary to predict the long-term effects on ice landmasses. Read more
Photooxidants from brown carbon and other chromophores in illuminated particle extracts Atmospheric Chemistry and Physics DOI 10.5194/acp-19-6579-2019 17 May 2019 We measured hydroxyl radical (•OH), singlet oxygen (1O2*), and organic triplets (3C*) in illuminated aqueous particle extracts. After measuring the impact of dilution on oxidant concentrations, we extrapolated our results to predict them in ambient particles –1O2* and3C* concentrations appear to be greatly enhanced, while•OH appears largely unchanged. Two of these oxidants (1O2*,3C*) are not yet included in atmospheric models, and our results make it possible to include them in the future. Read more
Northern Hemisphere continental winter warming following the 1991 Mt. Pinatubo eruption: reconciling models and observations Atmospheric Chemistry and Physics DOI 10.5194/acp-19-6351-2019 15 May 2019 This study provides compelling new evidence that the surface winter warming observed over the Northern Hemisphere continents following the 1991 eruption of Mt. Pinatubo was, very likely, completely unrelated to the eruption. This result has implications for earlier eruptions, as the evidence presented here demonstrates that the surface signal of even the very largest known eruptions may be swamped by the internal variability at high latitudes. Read more
Time-lapse gravity and levelling surveys reveal mass loss and ongoing subsidence in the urban subrosion-prone area of Bad Frankenhausen, Germany Solid Earth DOI 10.5194/se-10-599-2019 13 May 2019 Subrosion, i.e. the underground leaching of soluble rocks, causes disastrous sinkhole events worldwide. We investigate the accompanying mass transfer using quarter-yearly time-lapse gravity campaigns over 4 years in the town of Bad Frankenhausen, Germany. After correcting for seasonal soil water content, we find evidence of underground mass loss and attempt to quantify its amount. This is the first study of its kind to prove the feasibility of this approach in an urban area. Read more
Quantifying variations in shortwave aerosol–cloud–radiation interactions using local meteorology and cloud state constraints Atmospheric Chemistry and Physics DOI 10.5194/acp-19-6251-2019 13 May 2019 Aerosols are released by natural and human activities. When aerosols encounter clouds they interact in what is known as the indirect effect. Brighter clouds are expected due to the microphysical response; however, certain environments can trigger a modified response. Limits on the stability, humidity, and cloud thickness are applied regionally to investigate local cloud responses to aerosol, resulting in a range of indirect effects that would result in significant cooling or slight warming. Read more
Using a coupled agent-based modeling approach to analyze the role of risk perception in water management decisions Hydrology and Earth System Sciences DOI 10.5194/hess-23-2261-2019 10 May 2019 This study applies a two-way coupled agent-based model (ABM) with a river-reservoir management model (RiverWare) to analyze the role of risk perception in water management decisions using the Bayesian inference mapping joined with the cost–loss model. The calibration results capture the dynamics of historical irrigated area and streamflow changes and suggest that the proposed framework improves the representation of human decision-making processes compared to conventional rule-based ABMs. Read more
Heterogeneous sulfate aerosol formation mechanisms during wintertime Chinese haze events: air quality model assessment using observations of sulfate oxygen isotopes in Beijing Atmospheric Chemistry and Physics DOI 10.5194/acp-19-6107-2019 8 May 2019 Sulfate is a key species contributing to particle formation and growth during wintertime Chinese haze events. This study combines observations and modeling of oxygen isotope signatures in sulfate aerosol to investigate its formation mechanisms, with a focus on heterogeneous production on aerosol surface via H2O2, O3, and NO2 and trace metal catalyzed oxidation. Contributions from different formation pathways are presented. Read more