Projections of hydrofluorocarbon (HFC) emissions and the resulting global warming based on recent trends in observed abundances and current policies Atmospheric Chemistry and Physics DOI 10.5194/acp-22-6087-2022 27 July 2022 The emissions of hydrofluorocarbons (HFCs) have increased significantly in the past as a result of the phasing out of ozone-depleting substances. Observations indicate that HFCs are used much less in certain refrigeration applications than previously projected. Current policies are projected to reduce emissions and the surface temperature contribution of HFCs from 0.28–0.44 °C to 0.14–0.31 °C in 2100. The Kigali Amendment is projected to reduce the contributions further to 0.04 °C in 2100. Read more
Marine heatwaves in the Arabian Sea Ocean Science DOI 10.5194/os-18-639-2022 25 July 2022 Marine heatwaves refer to discrete, prolonged warm ocean conditions known to cause severe destruction in marine ecosystems. We find that coastal waters off the west coast of India have experienced a rapid multifold increase in heatwave days since the early 80s. This resulted in more frequent and longer marine heatwave events in the last decade. We show that the rapid warming in the Arabian Sea in the last decade is the primary cause of the observed enhanced heatwave events in this basin. Read more
Using neural networks to improve simulations in the gray zone Nonlinear Processes in Geophysics DOI 10.5194/npg-29-171-2022 22 July 2022 Our regional numerical weather prediction models run at kilometer-scale resolutions. Processes that occur at smaller scales not yet resolved contribute significantly to the atmospheric flow. We use a neural network (NN) to represent the unresolved part of physical process such as cumulus clouds. We test this approach on a simplified, yet representative, 1D model and find that the NN corrections vastly improve the model forecast up to a couple of days. Read more
Establishing an integrated workflow identifying and linking surface and subsurface lineaments for mineral exploration under cover: example from the Gawler Craton, South Australia Solid Earth DOI 10.5194/se-13-827-2022 20 July 2022 The insights of this study will help to improve our understanding on how to identify basement linear structures and how these lineaments could be related to surface lineaments or geology in the context of the Central Gawler Craton, South Australia. This contribution suggests a targeting concept for identifying the structural footprint of subsurface mineral systems by combining remotely sensed data corresponding to surface and subsurface features. Read more
HESS Opinions: Chemical transport modeling in subsurface hydrological systems – space, time, and the “holy grail” of “upscaling” Hydrology and Earth System Sciences DOI 10.5194/hess-26-2161-2022 18 July 2022 Extensive efforts have focused on quantifying conservative chemical transport in geological formations. We assert that an explicit accounting of temporal information, under uncertainty, in addition to spatial information, is fundamental to an effective modelling formulation. We further assert that efforts to apply chemical transport equations at large length scales, based on measurements and model parameter values relevant to significantly smaller length scales, are an unattainable “holy grail”. Read more
Technical Note: Past and future warming – direct comparison on multi-century timescales Climate of the Past DOI 10.5194/cp-18-911-2022 15 July 2022 Global mean surface temperatures are rising to levels unprecedented in over 100 000 years. This conclusion takes into account both recent global warming and likely future warming, which thereby enables a direct comparison with paleotemperature reconstructions on multi-century timescales. Read more
The Lehtinen–Pirjola method modified for efficient modelling of geomagnetically induced currents in multiple voltage levels of a power network Annales Geophysicae DOI 10.5194/angeo-40-205-2022 13 July 2022 The Lehtinen-Pirjola (LP) method is widely used for modelling geomagnetically induced currents (GIC) in power systems but was developed when the main aim was to model GIC in only the highest voltage level of a power network. Here we present a modification to the LP method designed to provide an efficient method for modelling GIC in multiple voltage levels. We also show how existing software can easily be converted to the new method and provide examples of calculations. Read more
Coupling human and natural systems for sustainability: experience from China’s Loess Plateau Earth System Dynamics DOI 10.5194/esd-13-795-2022 11 July 2022 To understand the dynamics of a coupled human and natural system (CHANS) and promote its sustainability, we propose a conceptual “pattern-process-service-sustainability” cascade framework. The use of this framework is systematically illustrated by a review of CHANS research experience in China’s Loess Plateau in terms of coupling landscape patterns and ecological processes, linking ecological processes to ecosystem services, and promoting social-ecological sustainability. Read more
Impact of bioenergy crop expansion on climate–carbon cycle feedbacks in overshoot scenarios Earth System Dynamics DOI 10.5194/esd-13-779-2022 8 July 2022 The deployment of bioenergy crops for capturing carbon from the atmosphere facilitates global warming mitigation via generating negative CO2 emissions. Here, we explored the consequences of large-scale energy crops deployment on the land carbon cycle. The land-use change for energy crops leads to carbon emissions and loss of future potential increase in carbon uptake by natural ecosystems. This impact should be taken into account by the modelling teams and accounted for in mitigation policies. Read more
Advances in air quality research – current and emerging challenges Atmospheric Chemistry and Physics DOI 10.5194/acp-22-4615-2022 6 July 2022 This review of air quality research focuses on developments over the past decade. The article considers current and future challenges that are important from air quality research and policy perspectives and highlights emerging prominent gaps of knowledge. The review also examines how air pollution management needs to adapt to new challenges and makes recommendations to guide the direction for future air quality research within the wider community and to provide support for policy. Read more
Enhancing MAX-DOAS atmospheric state retrievals by multispectral polarimetry – studies using synthetic data Atmospheric Measurement Techniques DOI 10.5194/amt-15-2077-2022 4 July 2022 MAX-DOAS is a widely used measurement technique for the remote detection of atmospheric aerosol and trace gases. It relies on the analysis of ultra-violet and visible radiation spectra of skylight. To date, information contained in the skylight’s polarisation state has not been utilised. On the basis of synthetic data, we carried out sensitivity analyses to assess the potential of polarimetry for MAX-DOAS applications. Read more
Low biodegradability of particulate organic carbon mobilized from thaw slumps on the Peel Plateau, NT, and possible chemosynthesis and sorption effects Biogeosciences DOI 10.5194/bg-19-1871-2022 1 July 2022 Permafrost thaw-driven landslides in the western Arctic are increasing organic carbon delivered to headwaters of drainage networks in the western Canadian Arctic by orders of magnitude. Through a series of laboratory experiments, we show that less than 10% of this organic carbon is likely to be mineralized to greenhouse gases during transport in these networks. Rather most of the organic carbon is likely destined for burial and sequestration for centuries to millennia. Read more
A stratospheric prognostic ozone for seamless Earth system models: performance, impacts and future Atmospheric Chemistry and Physics DOI 10.5194/acp-22-4277-2022 29 June 2022 The stratosphere is emerging as one of the keys to improve tropospheric weather and climate predictions. This study provides evidence of the role the stratospheric ozone layer plays in improving weather predictions at different timescales. Using a new ozone modelling approach suitable for high-resolution global models that provide operational forecasts from days to seasons, we find significant improvements in stratospheric meteorological fields and stratosphere–troposphere coupling. Read more
Comparing the transport-limited and ξ–q models for sediment transport Earth Surface Dynamics DOI 10.5194/esurf-10-301-2022 27 June 2022 By comparing two models for the transport of sediment, we find that they share a similar steady-state solution that adequately predicts the shape of most depositional systems made of a fan and an alluvial plain. The length of the fan is controlled by the size of the mountain drainage area feeding the sedimentary system and its slope by the incoming sedimentary flux. We show that the models differ in their transient behaviour to external forcing and are characterized by different response times. Read more
Uncertainty estimation with deep learning for rainfall–runoff modeling Hydrology and Earth System Sciences DOI 10.5194/hess-26-1673-2022 24 June 2022 This contribution evaluates distributional run-off predictions from deep-learning-based approaches. We propose a benchmarking setup and establish four strong baselines. The results show that accurate, precise, and reliable uncertainty estimation can be achieved with deep learning. Read more
Full latitudinal marine atmospheric measurements of iodine monoxide Atmospheric Chemistry and Physics DOI 10.5194/acp-22-4005-2022 22 June 2022 We have undertaken atmospheric iodine monoxide (IO) observations in the global marine boundary layer with a wide latitudinal coverage and sea surface temperature (SST) range. We conclude that atmospheric iodine is abundant over the Western Pacific warm pool, appearing as an iodine fountain, where ozone (O3) minima occur. Our study also found negative correlations between IO and O3 concentrations over IO maxima, which requires reconsideration of the initiation process of halogen activation. Read more
Arctic glaciers and ice caps through the Holocene:a circumpolar synthesis of lake-based reconstructions Climate of the Past DOI 10.5194/cp-18-579-2022 20 June 2022 This paper synthesizes 66 records of glacier variations over the Holocene from lake archives across seven Arctic regions. We find that summers only moderately warmer than today drove major environmental change across the Arctic in the early Holocene, including the widespread loss of glaciers. In comparison, future projections of Arctic temperature change far exceed estimated early Holocene values in most locations, portending the eventual loss of most of the Arctic’s small glaciers. Read more
Strong increase in thawing of subsea permafrost in the 22nd century caused by anthropogenic climate change The Cryosphere DOI 10.5194/tc-16-1057-2022 17 June 2022 Thawing permafrost releases carbon to the atmosphere, enhancing global warming. Part of the permafrost soils have been flooded by rising sea levels since the last ice age, becoming subsea permafrost (SSPF). The SSPF is less studied than the part on land. In this study we use a global model to obtain rates of thawing of SSPF under different future climate scenarios until the year 3000. After the year 2100 the scenarios strongly diverge, closely connected to the eventual disappearance of sea ice. Read more
Towards hybrid modeling of the global hydrological cycle Hydrology and Earth System Sciences DOI 10.5194/hess-26-1579-2022 15 June 2022 We present a physics-aware machine learning model of the global hydrological cycle. As the model uses neural networks under the hood, the simulations of the water cycle are learned from data, and yet they are informed and constrained by physical knowledge. The simulated patterns lie within the range of existing hydrological models and are plausible. The hybrid modeling approach has the potential to tackle key environmental questions from a novel perspective. Read more
Evaporation enhancement drives the European water-budget deficit during multi-year droughts Hydrology and Earth System Sciences DOI 10.5194/hess-26-1527-2022 13 June 2022 Droughts are a creeping disaster, meaning that their onset, duration and recovery are challenging to monitor and forecast. Here, we provide further evidence of an additional challenge of droughts, i.e. the fact that the deficit in water supply during droughts is generally much more than expected based on the observed decline in precipitation. At a European scale we explain this with enhanced evapotranspiration, sustained by higher atmospheric demand for moisture during such dry periods. Read more