Effective radiative forcing and adjustments in CMIP6 models Atmospheric Chemistry and Physics DOI 10.5194/acp-20-9591-2020 3 September 2020 The spread in effective radiative forcing for both CO 2 and aerosols is narrower in the latest CMIP6 (Coupled Model Intercomparison Project) generation than in CMIP5. For the case of CO 2 it is likely that model radiation parameterisations have improved. Tropospheric and stratospheric radiative adjustments to the forcing behave differently for different forcing agents, and there is still significant diversity in how clouds respond to forcings, particularly for total anthropogenic forcing. Read more
Emergent constraints on transient climate response (TCR) and equilibrium climate sensitivity (ECS) from historical warming in CMIP5 and CMIP6 models Earth System Dynamics DOI 10.5194/esd-11-737-2020 3 September 2020 One of the key questions in climate science is how much more heating we will get for a given rise in carbon dioxide in the atmosphere. A new generation of models showed that this might be more than previously expected. Comparing the new models to observed temperature rise since 1970, we show that there is no need to revise the estimate upwards. Air pollution, whose effect on climate warming is poorly understood, stopped rising, allowing us to better constrain the greenhouse gas signal. Read more
Open weather and climate science in the digital era Geoscience Communication DOI 10.5194/gc-3-191-2020 1 September 2020 At the 14th IEEE International eScience Conference domain specialists and data and computer scientists discussed the road towards open weather and climate science. Open science offers manifold opportunities but goes beyond sharing code and data. Besides domain-specific technical challenges, we observed that the main challenges are non-technical and impact the system of science as a whole. Read more
A global analysis of climate-relevant aerosol properties retrieved from the network of Global AtmosphereWatch (GAW) near-surface observatories Atmospheric Measurement Techniques DOI 10.5194/amt-13-4353-2020 1 September 2020 The paper establishes the fiducial reference of the GAW aerosol network providing the fully characterized value chain to the provision of four climate-relevant aerosol properties from ground-based sites. Data from almost 90 stations worldwide are reported for a reference year, 2017, providing a unique and very robust view of the variability of these variables worldwide. Current gaps in the GAW network are analysed and requirements for the Global Climate Monitoring System are proposed. Read more
Anthropogenic climate change and glacier lake outburst flood risk: local and global drivers and responsibilities for the case of lake Palcacocha, Peru Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2175-2020 27 August 2020 There is increasing interest and need to analyze the contribution of anthropogenic climate change to negative impacts of climate change. We study the case of glacial lake Palcacocha in Peru, which poses a significant flood risk to the city of Huaraz. We found that greenhouse gas emissions; strong urbanization processes without appropriate land use planning; and social, cultural, political, and institutional factors all contribute to the existing flood risk. Read more
The shared socio-economic pathway (SSP) greenhouse gas concentrations and their extensions to 2500 Geoscientific Model Development DOI 10.5194/gmd-13-3571-2020 27 August 2020 This study provides the future greenhouse gas (GHG) concentrations under the new set of so-called SSP scenarios (the successors of the IPCC SRES and previous representative concentration pathway (RCP) scenarios). The projected CO 2 concentrations range from 350 ppm for low-emission scenarios by 2150 to more than 2000 ppm under the high-emission scenarios. We also provide concentrations, latitudinal gradients, and seasonality for most of the other 42 considered GHGs. Read more
Rainfall intensification increases the contribution of rewetting pulses tosoil heterotrophic respiration Biogeosciences DOI 10.5194/bg-17-4007-2020 25 August 2020 Carbon dioxide is produced by soil microbes through respiration, which is particularly fast when soils are moistened by rain. Will respiration increase with future more intense rains and longer dry spells? With a mathematical model, we show that wetter conditions increase respiration. In contrast, if rainfall totals stay the same, but rain comes all at once after long dry spells, the average respiration will not change, but the contribution of the respiration bursts after rain will increase. Read more
An overview of and issues with sky radiometer technology and SKYNET Atmospheric Measurement Techniques DOI 10.5194/amt-13-4195-2020 25 August 2020 This paper overviews the progress in sky radiometer technology and the development of the network called SKYNET. It is found that the technology has produced useful on-site calibration methods, retrieval algorithms, and data analyses from sky radiometer observations of aerosol, cloud, water vapor, and ozone. The paper also discusses current issues of SKYNET to provide better information for the community. Read more
CloudRoots: integration of advanced instrumental techniques and processmodelling of sub-hourly and sub-kilometre land–atmosphere interactions Biogeosciences DOI 10.5194/bg-17-4375-2020 25 August 2020 The CloudRoots field experiment has obtained an open comprehensive observational data set that includes soil, plant, and atmospheric variables to investigate the interactions between a heterogeneous land surface and its overlying atmospheric boundary layer, including the rapid perturbations of clouds in evapotranspiration. Our findings demonstrate that in order to understand and represent diurnal variability, we need to measure and model processes from the leaf to the landscape scales. Read more
A monitoring system for spatiotemporal electrical self-potential measurements in cryospheric environments Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-9-317-2020 20 August 2020 In times of global warming, permafrost is starting to degrade at alarming rates, requiring new and improved characterization approaches. We describe the design and test installation, as well as detailed data quality assessment, of a monitoring system used to capture natural electrical potentials in the subsurface. These self-potential signals are of great interest for the noninvasive investigation of water flow in the non-frozen or partially frozen subsurface. Read more
Revisiting the global hydrological cycle: is it intensifying? Hydrology and Earth System Sciences DOI 10.5194/hess-24-3899-2020 20 August 2020 We overview and retrieve a great amount of global hydroclimatic data sets. We improve the quantification of the global hydrological cycle, its variability and its uncertainties through the surge of newly available data sets. We test (but do not confirm) established climatological hypotheses, according to which the hydrological cycle should be intensifying due to global warming. We outline a stochastic view of hydroclimate, which provides a reliable means of dealing with its variability. Read more
Molecular understanding of new-particle formation from α-pinene between-50 and +25 ∘C Atmospheric Chemistry and Physics DOI 10.5194/acp-20-9183-2020 18 August 2020 Highly oxygenated organic compounds (HOMs) have been identified as key vapors involved in atmospheric new-particle formation (NPF). The molecular distribution, HOM yield, and NPF from α-pinene oxidation experiments were measured at the CLOUD chamber over a wide tropospheric-temperature range. This study shows on a molecular scale that despite the sharp reduction in HOM yield at lower temperatures, the reduced volatility counteracts this effect and leads to an overall increase in the NPF rate. Read more
Relating climate sensitivity indices to projection uncertainty Earth System Dynamics DOI 10.5194/esd-11-721-2020 18 August 2020 Here, we assess the degree to which the idealized responses to transient forcing increase and step change forcing increase relate to warming under future scenarios. We find a possible explanation for the poor performance of transient metrics (relative to equilibrium response) as a metric of high-emission future warming in terms of their sensitivity to non-equilibrated initial conditions, and propose alternative metrics which better describe warming under high mitigation scenarios. Read more
Incremental improvements of 2030 targets insufficient to achieve the Paris Agreement goals Earth System Dynamics DOI 10.5194/esd-11-697-2020 13 August 2020 Current global mitigation ambition in the National Determined Contributions (NDCs) up to 2030 is insufficient to achieve the 1.5 °C long-term temperature limit. As governments are preparing new and updated NDCs for 2020, we address the question of what level of collective ambition is pivotal regarding the Paris Agreement goals. We provide estimates for global mean temperature increase by 2100 for different incremental NDC update scenarios and illustrate climate impacts under those scenarios. Read more
Remote sensing of methane leakage from natural gas and petroleum systems revisited Atmospheric Chemistry and Physics DOI 10.5194/acp-20-9169-2020 13 August 2020 The switch from the use of coal to natural gas or oil for energy generation potentially reduces the impact on global warming due to lower CO 2 emissions with the same energy content. However, this climate benefit is offset by fugitive methane emissions during the production and distribution process. We quantify emission and leakage rates relative to production for several large production regions based on satellite observations to evaluate the climate footprint of the gas and oil industry. Read more
Survival of the Qaidam mega-lake system under mid-Pliocene climates and itsrestoration under future climates Hydrology and Earth System Sciences DOI 10.5194/hess-24-3835-2020 11 August 2020 During the Pliocene, the Qaidam Basin on the Tibetan Plateau contained a mega-lake system. During the Pleistocene, it disappeared almost completely. Today, hyperarid climates prevail in the low-altitude parts of the basin. This study reveals that today’s mean water balance of the Qaidam Basin is nearly zero and is positive during warmer, less dry years. The results explain how the mega-lake system could survive for a long time in the past and could eventually be restored in the future. Read more
The recent state and variability of the carbonate system of the CanadianArctic Archipelago and adjacent basins in the context of ocean acidification Biogeosciences DOI 10.5194/bg-17-3923-2020 11 August 2020 Ocean acidification is the process by which the oceans are changing due to carbon dioxide emissions from human activities. Studying this process in the Arctic Ocean is essential as this ocean and its ecosystems are more vulnerable to the effects of acidification. Water chemistry measurements made in recent years show that waters in and around the Canadian Arctic Archipelago are considerably affected by this process and show dynamic conditions that might have an impact on local marine organisms. Read more
Impact of environmental changes and land management practices on wheatproduction in India Earth System Dynamics DOI 10.5194/esd-11-641-2020 6 August 2020 Spring wheat, a staple for millions of people in India and the world, is vulnerable to changing environmental and management factors. Using a new spring wheat model, we find that over the 1980–2016 period elevated CO 2 levels, irrigation, and nitrogen fertilizers led to an increase of 30 %, 12 %, and 15 % in countrywide production, respectively. In contrast, rising temperatures have reduced production by 18 %. These effects vary across the country, thereby affecting production at regional scales. Read more
Multidecadal trend analysis of in situ aerosol radiative properties around the world Atmospheric Chemistry and Physics DOI 10.5194/acp-20-8867-2020 6 August 2020 Long-term trends of aerosol radiative properties (52 stations) prove that aerosol load has significantly decreased over the last 20 years. Scattering trends are negative in Europe (EU) and North America (NA), not ss in Asia, and show a mix of positive and negative trends at polar stations. Absorption has mainly negative trends. The single scattering albedo has positive trends in Asia and eastern EU and negative in western EU and NA, leading to a global positive median trend of 0.02 % per year. Read more
Reviewing global estimates of surface reactive nitrogen concentration anddeposition using satellite retrievals Atmospheric Chemistry and Physics DOI 10.5194/acp-20-8641-2020 4 August 2020 Excessive atmospheric reactive nitrogen (N r ) deposition can cause a series of negative effects. Thus, it is necessary to accurately estimate N r deposition to evaluate its impact on the ecosystems and environment. Scientists attempted to estimate surface N r concentration and deposition using satellite retrievals. We give a thorough review of recent advances in estimating surface N r concentration and deposition using satellite retrievals of NO 2 and NH 3 and summarize the existing challenges. Read more
Invited perspectives: The volcanoes of Naples: how can the highest volcanic risk in the world be effectively mitigated? Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2037-2020 4 August 2020 This paper starts by showing the present low performance of eruption forecasting and then addresses the problem of effectively mitigating the highest volcanic risk in the world, represented by the Naples area (southern Italy). The problem is considered in a highly multidisciplinary way, taking into account the main economic, sociological and urban planning issues. Our study gives precise guidelines to assessing and managing volcanic risk in any densely urbanised area. Read more
Results of the third Marine Ice Sheet Model Intercomparison Project (MISMIP+) The Cryosphere DOI 10.5194/tc-14-2283-2020 30 July 2020 We present the results of the third Marine Ice Sheet Intercomparison Project (MISMIP+). MISMIP+ is one in a series of exercises that test numerical models of ice sheet flow in simple situations. This particular exercise concentrates on the response of ice sheet models to the thinning of their floating ice shelves, which is of interest because numerical models are currently used to model the response to contemporary and near-future thinning in Antarctic ice shelves. Read more
Spatial database and website for reservoir-triggered seismicity in Brazil Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2001-2020 30 July 2020 One of the biggest challenges in studying reservoir-triggered seismicity (RTS) is to identify factors that can trigger seismicity. A spatial database and a web viewer were created, gathering the data pertinent to the RTS study. Results were obtained in processing these data; for example, the occurrence of RTS increases with the height of the dam, the minimum limiting volume value is 1 × 10 −4 km 3 for occurrence of RTS, and for geology no correlations were found, among other results. Read more
Coastal impacts of Storm Gloria (January 2020) over the north-western Mediterranean Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-1955-2020 28 July 2020 Storm Gloria hit the Mediterranean Spanish coastlines between 20 and 23 January 2020, causing severe damages such as flooding of the Ebro River delta. We evaluate its coastal impacts with a numerical simulation of the wind waves and the accumulated ocean water along the coastline (storm surge). The storm surge that reached values up to 1 m was mainly driven by the wind that also generated wind waves up to 8 m in height. We also determine the extent of the Ebro Delta flooded by marine water. Read more
Mātauranga Māori in geomorphology: existing frameworks, case studies, and recommendations for incorporating Indigenous knowledge in Earth science Earth Surface Dynamics DOI 10.5194/esurf-8-595-2020 28 July 2020 This review highlights potential contributions that Indigenous knowledge can make to geomorphic research. We evaluate several frameworks and models for including Indigenous knowledge in geomorphic research and discuss how they can be adapted for use with Indigenous communities across the world. We propose that weaving Indigenous knowledge with geomorphic science has the potential to create new solutions and understandings that neither body of knowledge could produce in isolation. Read more
Smoke of extreme Australian bushfires observed in the stratosphere over Punta Arenas, Chile, in January 2020: optical thickness, lidar ratios, and depolarization ratios at 355 and 532 nm Atmospheric Chemistry and Physics DOI 10.5194/acp-20-8003-2020 23 July 2020 Unique lidar observations of a strong perturbation in stratospheric aerosol conditions in the Southern Hemisphere caused by the extreme Australian bushfires in 2019–2020 are presented. One of the main goals of this article is to provide the CALIPSO and Aeolus spaceborne lidar science teams with basic input parameters (lidar ratios, depolarization ratios) for a trustworthy documentation of this record-breaking event. Read more
Why does a conceptual hydrological model fail to correctly predict discharge changes in response to climate change? Hydrology and Earth System Sciences DOI 10.5194/hess-24-3493-2020 23 July 2020 We investigate why a conceptual hydrological model failed to correctly predict observed discharge changes in response to increasing precipitation and air temperature in 156 Austrian catchments. Simulations indicate that poor model performance is related to two problems, namely a model structure that neglects changes in vegetation dynamics and inhomogeneities in precipitation data caused by changes in stations density with time. Other hypotheses did not improve simulated discharge changes. Read more
On giant shoulders: how a seamount affects the microbial communitycomposition of seawater and sponges Biogeosciences DOI 10.5194/bg-17-3471-2020 21 July 2020 Seamounts are globally abundant submarine structures that offer great potential to study the impacts and interactions of environmental gradients at a single geographic location. In an exemplary way, we describe potential mechanisms by which a seamount can affect the structure of pelagic and benthic (sponge-)associated microbial communities. We conclude that the geology, physical oceanography, biogeochemistry, and microbiology of seamounts are even more closely linked than currently appreciated. Read more
N2O changes from the Last Glacial Maximum to the preindustrial – Part 2: terrestrial N2O emissions and carbon–nitrogen cycle interactions Biogeosciences DOI 10.5194/bg-17-3511-2020 21 July 2020 Results of the first globally resolved simulations of terrestrial carbon and nitrogen (N) cycling and N 2 O emissions over the past 21 000 years are compared with reconstructed N 2 O emissions. Modelled and reconstructed emissions increased strongly during past abrupt warming events. This evidence appears consistent with a dynamic response of biological N fixation to increasing N demand by ecosystems, thereby reducing N limitation of plant productivity and supporting a land sink for atmospheric CO 2 . Read more
The MOSAiC ice floe: sediment-laden survivor from the Siberian shelf The Cryosphere DOI 10.5194/tc-14-2173-2020 16 July 2020 In October 2019 the research vessel Polarstern was moored to an ice floe in order to travel with it on the 1-year-long MOSAiC journey through the Arctic. Here we provide historical context of the floe’s evolution and initial state for upcoming studies. We show that the ice encountered on site was exceptionally thin and was formed on the shallow Siberian shelf. The analyses presented provide the initial state for the analysis and interpretation of upcoming biogeochemical and ecological studies. Read more
The enigmatic curvature of Central Iberia and its puzzling kinematics Solid Earth DOI 10.5194/se-11-1247-2020 16 July 2020 Pangea was assembled during Devonian to early Permian times and resulted in a large-scale and winding orogeny that today transects Europe, northwestern Africa, and eastern North America. This orogen is characterized by an S shape corrugated geometry in Iberia. This paper presents the advances and milestones in our understanding of the geometry and kinematics of the Central Iberian curve from the last decade with particular attention paid to structural and paleomagnetic studies. Read more
Landfast sea ice material properties derived from ice bridge simulations using the Maxwell elasto-brittle rheology The Cryosphere DOI 10.5194/tc-14-2137-2020 14 July 2020 We study the formation of ice arches between two islands using a model that resolves crack initiation and propagation. This model uses a damage parameter to parameterize the presence or absence of cracks in the ice. We find that the damage parameter allows for cracks to propagate in the ice but in a different orientation than predicted by theory. The results call for improvement in how stress relaxation associated with this damage is parameterized. Read more
Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections Biogeosciences DOI 10.5194/bg-17-3439-2020 14 July 2020 We assess 21st century projections of marine biogeochemistry in the CMIP6 Earth system models. These models represent the most up-to-date understanding of climate change. The models generally project greater surface ocean warming, acidification, subsurface deoxygenation, and euphotic nitrate reductions but lesser primary production declines than the previous generation of models. This has major implications for the impact of anthropogenic climate change on marine ecosystems. Read more
Lower-thermosphere response to solar activity: an empirical-mode-decomposition analysis of GOCE 2009–2012 data Annales Geophysicae DOI 10.5194/angeo-38-789-2020 9 July 2020 Forecasting the thermosphere (atmosphere’s uppermost layer from 90 to 800 km altitude) is crucial to space mission design, spacecraft operations and space surveillance. The thermosphere is controlled by the Sun through variable solar extreme-ultraviolet radiation and the solar wind. We show how the solar indices Mg II and Ap may be used in forecasting thermospheric density at 260 km, a very low altitude, where the GOCE satellite operated from 2009 to 2013, during the full rise of solar cycle 24. Read more
Identifying a regional aerosol baseline in the eastern North Atlantic using collocated measurements and a mathematical algorithm to mask high-submicron-number-concentration aerosol events Atmospheric Chemistry and Physics DOI 10.5194/acp-20-7553-2020 9 July 2020 Continuous high-time-resolution ambient data can include periods when aerosol properties do not represent regional aerosol processes due to high-concentration local events. We develop a novel aerosol mask at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) facility in the eastern North Atlantic (ENA). We use two ground sites to validate the mask, include a comparison with aircraft overflights, and provide guidance to increase data quality at ENA and other locations. Read more
The contribution of microbial communities in polymetallic nodules to thediversity of the deep-sea microbiome of the Peru Basin (4130–4198 mdepth) Biogeosciences DOI 10.5194/bg-17-3203-2020 7 July 2020 Industrial-scale mining of deep-sea polymetallic nodules will remove nodules in large areas of the sea floor. We describe community composition of microbes associated with nodules of the Peru Basin. Our results show that nodules provide a unique ecological niche, playing an important role in shaping the diversity of the benthic deep-sea microbiome and potentially in element fluxes. We believe that our findings are highly relevant to expanding our knowledge of the impact associated with mining. Read more
Enhanced growth rate of atmospheric particles from sulfuric acid Atmospheric Chemistry and Physics DOI 10.5194/acp-20-7359-2020 7 July 2020 Sulfuric acid is a major atmospheric vapour for aerosol formation. If new particles grow fast enough, they can act as cloud droplet seeds or affect air quality. In a controlled laboratory set-up, we demonstrate that van der Waals forces enhance growth from sulfuric acid. We disentangle the effects of ammonia, ions and particle hydration, presenting a complete picture of sulfuric acid growth from molecular clusters onwards. In a climate model, we show its influence on the global aerosol budget. Read more
The role of prior assumptions in carbon budget calculations Earth System Dynamics DOI 10.5194/esd-11-563-2020 2 July 2020 Levels of future temperature change are often used interchangeably with carbon budget allowances in climate policy, a relatively robust relationship on the timescale of this century. However, recent advances in understanding underline that continued warming after net-zero emissions have been achieved cannot be ruled out by observations of warming to date. We consider here how such behavior could be constrained and how policy can be framed in the context of these uncertainties. Read more
Snow avalanche detection and mapping in multitemporal and multiorbital radar images from TerraSAR-X and Sentinel-1 Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-1783-2020 2 July 2020 To assess snow avalanche mapping with radar satellites in Switzerland, we compare 2 m resolution TerraSAR-X images, 10 m resolution Sentinel-1 images, and optical 1.5 m resolution SPOT-6 images. We found that radar satellites provide a valuable option to map at least larger avalanches, though avalanches are mapped only partially. By combining multiple orbits and polarizations from S1, we achieved mapping results of quality almost comparable to single high-resolution TerraSAR-X images. Read more
Towards an objective assessment of climate multi-model ensembles – a casestudy: the Senegalo-Mauritanian upwelling region Geoscientific Model Development DOI 10.5194/gmd-13-2723-2020 30 June 2020 The most robust representation of climate is usually obtained by averaging a large number of simulations, thereby cancelling individual model errors. Here, we work towards an objective way of selecting the least biased models over a certain region, based on physical parameters. This statistical method based on a neural classifier and multi-correspondence analysis is illustrated here for the Senegalo-Mauritanian region, but it could potentially be developed for any other region or process. Read more
Modelling the potential impacts of the recent, unexpected increase in CFC-11 emissions on total column ozone recovery Atmospheric Chemistry and Physics DOI 10.5194/acp-20-7153-2020 30 June 2020 The Montreal Protocol was agreed in 1987 to limit and then stop the production of man-made CFCs, which destroy stratospheric ozone. As a result, the atmospheric abundances of CFCs are now declining in the atmosphere. However, the atmospheric abundance of CFC-11 is not declining as expected under complete compliance with the Montreal Protocol. Using the UM-UKCA chemistry–climate model, we explore the impact of future unregulated production of CFC-11 on ozone recovery. Read more
Changes of the Arctic marginal ice zone during the satellite era The Cryosphere DOI 10.5194/tc-14-1971-2020 25 June 2020 It is well known that the Arctic sea ice extent is declining, and it is often assumed that the marginal ice zone (MIZ), the area of partial sea ice cover, is consequently increasing. However, we find no trend in the MIZ extent during the last 40 years from observations that is consistent with a widening of the MIZ as it moves northward. Differences of MIZ extent between different satellite retrievals are too large to provide a robust basis to verify model simulations of MIZ extent. Read more
Is there warming in the pipeline? A multi-model analysis of the Zero Emissions Commitment from CO2 Biogeosciences DOI 10.5194/bg-17-2987-2020 25 June 2020 The Zero Emissions Commitment (ZEC) is the change in global temperature expected to occur following the complete cessation of CO 2 emissions. Here we use 18 climate models to assess the value of ZEC. For our experiment we find that ZEC 50 years after emissions cease is between −0.36 to +0.29 °C. The most likely value of ZEC is assessed to be close to zero. However, substantial continued warming for decades or centuries following cessation of CO 2 emission cannot be ruled out. Read more
RainNet v1.0: a convolutional neural network for radar-based precipitation nowcasting Geoscientific Model Development DOI 10.5194/gmd-13-2631-2020 23 June 2020 In this study, we present RainNet, a deep convolutional neural network for radar-based precipitation nowcasting, which was trained to predict continuous precipitation intensities at a lead time of 5 min. RainNet significantly outperformed the benchmark models at all lead times up to 60 min. Yet, an undesirable property of RainNet predictions is the level of spatial smoothing. Obviously, RainNet learned an optimal level of smoothing to produce a nowcast at 5 min lead time. Read more
Changing global cropping patterns to minimize national blue water scarcity Hydrology and Earth System Sciences DOI 10.5194/hess-24-3015-2020 18 June 2020 Previous studies on water saving through food trade focussed either on comparing water productivities among countries or on analysing food trade in relation to national water endowments. Here, we consider, for the first time, both differences in water productivities and water endowments to analyse national comparative advantages. Our study reveals that blue water scarcity can be reduced to sustainable levels by changing cropping patterns while maintaining current levels of global production. Read more
New observations of the distribution, morphology and dissolution dynamics of cryogenic gypsum in the Arctic Ocean The Cryosphere DOI 10.5194/tc-14-1795-2020 16 June 2020 Based on an observed omnipresence of gypsum crystals, we concluded that their release from melting sea ice is a general feature in the Arctic Ocean. Individual gypsum crystals sank at more than 7000 m d −1 , suggesting that they are an important ballast mineral. Previous observations found gypsum inside phytoplankton aggregates at 2000 m depth, supporting gypsum as an important driver for pelagic-benthic coupling in the ice-covered Arctic Ocean. Read more
Induced seismicity risk analysis of the hydraulic stimulation of a geothermal well on Geldinganes, Iceland Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-1573-2020 16 June 2020 This study presents a first-of-its-kind pre-drilling probabilistic induced seismic risk analysis for the Geldinganes (Iceland) deep-hydraulic stimulation. The results of the assessment indicate that the individual risk within a radius of 2 km around the injection point is below the safety limits. However, the analysis is affected by a large variability due to the presence of pre-drilling deep uncertainties. This suggests the need for online risk updating during the stimulation. Read more
Linking economic and social factors to peak flows in an agricultural watershed using socio-hydrologic modeling Hydrology and Earth System Sciences DOI 10.5194/hess-24-2873-2020 11 June 2020 We describe a socio-hydrologic model that couples an agent-based model (ABM) of human decision-making with a hydrologic model. We establish this model for a typical agricultural watershed in Iowa, USA, and simulate the evolution of large discharge events over a 47-year period under changing land use. Using this modeling approach, relationships between seemingly unrelated variables such as crop markets or crop yields and local peak flow trends are quantified. Read more
Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs Hydrology and Earth System Sciences DOI 10.5194/hess-24-2921-2020 11 June 2020 Many previous studies using offline drought indices report that future warming will increase worldwide drought. However, this contradicts observations/projections of vegetation greening and increased runoff. We resolved this paradox by re-calculating the same drought indices using direct climate model outputs and find no increase in future drought as the climate warms. We also find that accounting for the impact of CO 2 on plant transpiration avoids the previous overestimation of drought. Read more
N2O isotopocule measurements using laser spectroscopy: analyzer characterization and intercomparison Atmospheric Measurement Techniques DOI 10.5194/amt-13-2797-2020 10 June 2020 The latest commercial laser spectrometers have the potential to revolutionize N 2 O isotope analysis. However, to do so, they must be able to produce trustworthy data. Here, we test the performance of widely used laser spectrometers for ambient air applications and identify instrument-specific dependencies on gas matrix and trace gas concentrations. We then provide a calibration workflow to facilitate the operation of these instruments in order to generate reproducible and accurate data. Read more