Assessing the representation of the Australian carbon cycle in global vegetation models Biogeosciences DOI 10.5194/bg-18-5639-2021 7 January 2022 The Australian continent is included in global assessments of the carbon cycle such as the global carbon budget, yet the performance of dynamic global vegetation models (DGVMs) over Australia has rarely been evaluated. We assessed simulations by an ensemble of dynamic global vegetation models over Australia and highlighted a number of key areas that lead to model divergence on both short (inter-annual) and long (decadal) timescales. Read more
Assessment of direct economic losses of flood disasters based on spatial valuation of land use and quantification of vulnerabilities: a case study on the 2014 flood in Lishui city of China Natural Hazards and Earth System Sciences DOI 10.5194/nhess-21-3161-2021 5 January 2022 Taking a single flood disaster in Lishui city as an example, a rapid and refined assessment of economic loss is studied and verified, which can effectively simulate the distribution of loss ratio and loss value. It includes the construction of land use type and value based on data fusion and an expert questionnaire survey, the fitting and calibration of vulnerability curves based on an existing database and disaster loss reporting, and estimation of loss ratio and loss value by spatial analysis. Read more
Self-consistent global transport of metallic ions with WACCM-X Atmospheric Chemistry and Physics DOI 10.5194/acp-21-15619-2021 3 January 2022 Metal layers occur in the MLT region (80–120 km) from the ablation of cosmic dust. The latest lidar observations show these metals can reach a height approaching 200 km, which is challenging to explain. We have developed the first global simulation incorporating the full life cycle of metal atoms and ions. The model results compare well with lidar and satellite observations of the seasonal and diurnal variation of the metals and demonstrate the importance of ion mass and ion-neutral coupling. Read more
Direct estimates of biomass burning NOx emissions and lifetimes using daily observations from TROPOMI Atmospheric Chemistry and Physics DOI 10.5194/acp-21-15569-2021 31 December 2021 We describe direct estimates of NOx emissions and lifetimes for biomass burning plumes using daily TROPOMI retrievals of NO2. Satellite-derived NOx emission factors are consistent with those from in situ measurements. We observe decreasing NOx lifetime with fire intensity, which is due to the increase in NOx abundance and radical production. Our findings suggest promise for applying space-based observations to track the emissions and chemical evolution of reactive nitrogen from wildfires. Read more
New insights into the ∼ 74 ka Toba eruption from sulfur isotopes of polar ice cores Climate of the Past DOI 10.5194/cp-17-2119-2021 29 December 2021 The ~ 74 ka eruption of Toba was one of the largest eruptions of the last 100 ka. We have measured the sulfur isotopic composition for 11 Toba eruption candidates in two Antarctic ice cores. Sulfur isotopes allow us to distinguish between large eruptions that have erupted material into the stratosphere and smaller ones that reach lower altitudes. Using this we have identified the events most likely to be Toba and place the eruption on the transition into a cold period in the Northern Hemisphere. Read more
Evaluating integrated water management strategies to inform hydrological drought mitigation Natural Hazards and Earth System Sciences DOI 10.5194/nhess-21-3113-2021 27 December 2021 Managing water demand and supply during droughts is complex, as highly pressured human–water systems can overuse water sources to maintain water supply. We evaluated the impact of drought policies on water resources using a socio-hydrological model. For a range of hydrogeological conditions, we found that integrated drought policies reduce baseflow and groundwater droughts most if extra surface water is imported, reducing the pressure on water resources during droughts. Read more
Vulnerability of European ecosystems to two compound dry and hot summers in 2018 and 2019 Earth System Dynamics DOI 10.5194/esd-12-1015-2021 24 December 2021 Temperate biomes in Europe are not prone to recurrent dry and hot conditions in summer. However, these conditions may become more frequent in the coming decades. Because stress conditions can leave legacies for many years, this may result in reduced ecosystem resilience under recurrent stress. We assess vegetation vulnerability to the hot and dry summers in 2018 and 2019 in Europe and find the important role of inter-annual legacy effects from 2018 in modulating the impacts of the 2019 event. Read more
How alkaline compounds control atmospheric aerosol particle acidity Atmospheric Chemistry and Physics DOI 10.5194/acp-21-14983-2021 22 December 2021 Aerosol particle pH is well-buffered by alkaline compounds, notably NH3 and crustal elements. NH3 is found to supply remarkable buffering capacity on a global scale, from the polluted continents to the remote oceans. Potential future changes in agricultural NH3 must be accompanied by strong reductions of SO2 and NOx to avoid particles becoming highly acidic, with implications for human health (aerosol toxicity), ecosystems (acid deposition), clouds, and climate (aerosol hygroscopicity). Read more
Aerosol–cloud interactions: the representation of heterogeneous ice activation in cloud models Atmospheric Chemistry and Physics DOI 10.5194/acp-21-15213-2021 20 December 2021 Aerosol–cloud interactions play an important role in climate change. Simulations of the competition between homogeneous solution droplet freezing and heterogeneous ice nucleation can be compromised by the misapplication of ice-active particle fractions frequently derived from laboratory measurements or parametrizations. Our study frames the problem and establishes a solution that is easy to implement in cloud models. Read more
Deep ice as a geochemical reactor: insights from iron speciation and mineralogy of dust in the Talos Dome ice core (East Antarctica) The Cryosphere DOI 10.5194/tc-15-4807-2021 17 December 2021 As scientists are pushing efforts to recover deep ice cores to extend paleoclimatic reconstructions, it is now essential to explore deep ice. The latter was considered a relatively stable environment, but this view is changing. This study shows that the conditions of deep ice promote the interaction between soluble and insoluble impurities, favoring complex geochemical reactions that lead to the englacial dissolution and precipitation of specific minerals present in atmospheric mineral dust. Read more
