Harmonising plant functional type distributions for evaluating Earth system models Climate of the Past DOI 10.5194/cp-15-335-2019 18 February 2019 A simple but powerful method for the biomisation of plant functional type distributions is introduced and tested for six different dynamic global vegetation models based on pre-industrial and palaeo-simulations. The method facilitates the direct comparison between vegetation distributions simulated by different Earth system models and between model results and the pollen-based biome reconstructions. It is therefore a powerful tool for the evaluation of Earth system models. Read more
Thaw processes in ice-rich permafrost landscapes represented with laterally coupled tiles in a land surface model The Cryosphere DOI 10.5194/tc-13-591-2019 18 February 2019 Many permafrost landscapes contain large amounts of excess ground ice, which gives rise to small-scale elevation differences. This results in lateral fluxes of snow, water, and heat, which we investigate and show how it can be accounted for in large-scale models. Using a novel model technique which can account for these differences, we are able to model both the current state of permafrost and how these landscapes change as permafrost thaws, in a way that could not previously be achieved. Read more
Towards a more complete quantification of the global carbon cycle Biogeosciences DOI 10.5194/bg-16-831-2019 14 February 2019 Globally, C is added to the atmosphere from fossil fuels and deforestation, balanced by ocean uptake and atmospheric increase. The difference (residual sink) is equated to plant uptake. But this omits cement carbonation; transport to oceans by dust; riverine organic C and volatile organics; and increased C in plastic, bitumen, wood, landfills, and lakes. Their inclusion reduces the residual sink from 3.6 to 2.1 GtC yr-1 and thus the inferred ability of the biosphere to alter human C emissions. Read more
A simple topography-driven and calibration-free runoff generation module Hydrology and Earth System Sciences DOI 10.5194/hess-23-787-2019 13 February 2019 Supported by large-sample ecological observations, a novel, simple and topography-driven runoff generation module (HSC-MCT) was created. The HSC-MCT is calibration-free, and therefore it can be used to predict in ungauged basins, and has great potential to be generalized at the global scale. Also, it allows us to reproduce the variation of saturation areas, which has great potential to be used for broader hydrological, ecological, climatological, and biogeochemical studies. Read more
Mineral formation induced by cable bacteria performing long-distance electron transport in marine sediments Biogeosciences DOI 10.5194/bg-16-811-2019 13 February 2019 Multicellular cable bacteria form long filaments that can reach lengths of several centimeters. They affect the chemistry and mineralogy of their surroundings and vice versa. How the surroundings affect the cable bacteria is investigated. They show three different types of biomineral formation: (1) a polymer containing phosphorus in their cells, (2) a sheath of clay surrounding the surface of the filament and (3) the encrustation of a filament via a solid phase containing iron and phosphorus. Read more
Evidence for a major missing source in the global chloromethane budget from stable carbon isotopes Atmospheric Chemistry and Physics DOI 10.5194/acp-19-1703-2019 8 February 2019 Chloromethane is the most important natural carrier of chlorine to the stratosphere. From a newly determined carbon isotope effect of −11.2 ‰ for the tropospheric loss of CH3Cl we derive a tropical rainforest CH3Cl source of 670 ± 200 Gg a−1, 60 % smaller than previous estimates. A revision of previous bottom-up estimates using above-ground biomass instead of rainforest area strongly supports this lower estimate. Our results suggest a large unknown tropical value of 1530 ± 200 Gg a−1. Read more
Four decades of Antarctic surface elevation changes from multi-mission satellite altimetry The Cryosphere DOI 10.5194/tc-13-427-2019 5 February 2019 We developed an approach to combine measurements of seven satellite altimetry missions over the Antarctic Ice Sheet. Our resulting monthly grids of elevation changes between 1978 and 2017 provide unprecedented details of the long-term and interannual variation. Derived mass changes agree well with contemporaneous data of surface mass balance and satellite gravimetry and show which regions were responsible for the significant accelerations of mass loss in recent years. Read more
Power spectra of random heterogeneities in the solid earth Solid Earth DOI 10.5194/se-10-275-2019 5 February 2019 Recent seismological observations clarified that the velocity structure of the crust and upper mantle is randomly heterogeneous. I compile reported power spectral density functions of random velocity fluctuations based on various types of measurements. Their spectral envelope is approximated by the third power of wavenumber. It is interesting to study what kinds of geophysical processes created such a power-law spectral envelope at different scales and in different geological environments. Read more
Emergent stationarity in Yellow River sediment transport and the underlying shift of dominance: from streamflow to vegetation Hydrology and Earth System Sciences DOI 10.5194/hess-23-549-2019 30 January 2019 Our study shows that there is declining coupling between sediment concentration and discharge from daily to annual scales for gauges across the Yellow River basin (YRB). Not only the coupling, but also the magnitude of sediment response to discharge variation decreases with long-term mean discharge. This emergent stationarity can be related to sediment retardation by vegetation, suggesting the shift of dominance from water to vegetation as mean annual discharge increases. Read more
Long-term erosion of the Nepal Himalayas by bedrock landsliding: the role of monsoons, earthquakes and giant landslides Earth Surface Dynamics DOI 10.5194/esurf-7-107-2019 25 January 2019 We mapped eight monsoon-related (> 100 m2) and large (> 0.1 km2) landslides in the Nepal Himalayas since 1970. Adding inventories of Holocene landslides, giant landslides (> 1 km3), and landslides from the 2015 Gorkha earthquake, we constrain the size–frequency distribution of monsoon- and earthquake-induced landslides. Both contribute ~50 % to a long-term (> 10 kyr) total erosion of ~2 mm yr-1, matching the long-term exhumation rate. Large landslides rarer than10Be sampling time drive erosion. Read more
Stable carbon and nitrogen isotopic composition of leaves, litter, and soils of various ecosystems along an elevational and land-use gradient at Mount Kilimanjaro, Tanzania Biogeosciences DOI 10.5194/bg-16-409-2019 25 January 2019 Mount Kilimanjaro is an iconic environmental asset under serious threat due to increasing human pressures and climate change constraints. We studied variations in the stable isotopic composition of carbon and nitrogen in plant, litter, and soil material sampled along a strong land-use and altitudinal gradient. Our results show that, besides management, increasing temperatures in a changing climate may promote carbon and nitrogen losses, thus altering the stability of Kilimanjaro ecosystems. Read more
Positive matrix factorization of organic aerosol: insights from a chemical transport model Atmospheric Chemistry and Physics DOI 10.5194/acp-19-973-2019 24 January 2019 The ability of positive matrix factorization (PMF) factor analysis to identify and quantify the organic aerosol (OA) sources accurately is tested in this modeling study. The estimated uncertainty of the contribution of fresh biomass burning is less than 30 % and of the other primary sources is less than 40 %, when these sources contribute more than 20 % to the OA. Τhe first oxygenated OA factor includes mainly highly aged OA, while the second oxygenated OA factor contains fresher secondary OA. Read more
Heinrich events show two-stage climate response in transient glacial simulations Climate of the Past DOI 10.5194/cp-15-153-2019 24 January 2019 Heinrich events are among the dominant modes of glacial climate variability. They are caused by massive ice discharges from the Laurentide Ice Sheet into the North Atlantic. In previous studies, the climate changes were either seen as resulting from freshwater released from the melt of the discharged icebergs or by ice sheet elevation changes. With a coupled ice sheet–climate model, we show that both effects are relevant with the freshwater effects preceding the ice sheet elevation effects. Read more
Quantifying new water fractions and transit time distributions using ensemble hydrograph separation: theory and benchmark tests Hydrology and Earth System Sciences DOI 10.5194/hess-23-303-2019 18 January 2019 How long does it take for raindrops to become streamflow? Here I propose a new approach to this old problem. I show how we can use time series of isotope data to measure the average fraction of same-day rainfall appearing in streamflow, even if this fraction varies greatly from rainstorm to rainstorm. I show that we can quantify how this fraction changes from small rainstorms to big ones, and from high flows to low flows, and how it changes with the lag time between rainfall and streamflow. Read more
Global atmospheric CO2 inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate Biogeosciences DOI 10.5194/bg-16-117-2019 16 January 2019 We have compared global carbon budgets calculated from numerical inverse models and CO2 observations, and evaluated how these systems reproduce vertical gradients in atmospheric CO2 from aircraft measurements. We found that available models have converged on near-neutral tropical total fluxes for several decades, implying consistent sinks in intact tropical forests, and that assumed fossil fuel emissions and predicted atmospheric growth rates are now the dominant axes of disagreement. Read more
A multi-technology analysis of the 2017 North Korean nuclear test Solid Earth DOI 10.5194/se-10-59-2019 15 January 2019 On 3 September 2017 official channels of the Democratic People’s Republic of Korea announced the successful test of a nuclear device. This study provides a multi-technology analysis of the 2017 North Korean event and its aftermath using a wide array of geophysical methods (seismology, infrasound, remote sensing, radionuclide monitoring, and atmospheric transport modeling). Our results clearly indicate that the September 2017 North Korean event was in fact a nuclear test. Read more
Demystifying academics to enhance university–business collaborations in environmental science Geoscience Communication DOI 10.5194/gc-2-1-2019 15 January 2019 Worldwide there is intense interest in converting research excellence in universities into commercial success, but there has been scant attention devoted to exactly how individual scientists’ workload and incentive structures may be a key barrier to this. Our work reveals the real challenge posed by a time-constrained university culture, better describes how work with business might fit into an academic job, and gives tips on working together in anuser guidefor scientists and (re)insurers. Read more
Indian winter and summer monsoon strength over the 4.2 ka BP event in foraminifer isotope records from the Indus River delta in the Arabian Sea Climate of the Past DOI 10.5194/cp-15-73-2019 15 January 2019 A foraminifer oxygen isotope record from the northeastern Arabian Sea was used to reconstruct winter and summer monsoon strength from 5.4 to 3.0 ka. We found a 200-year period of strengthened winter monsoon (4.5–4.3 ka) that coincides with the earliest phase of the Mature Harappan period of the Indus Civilization, followed by weakened winter and summer monsoons by 4.1 ka. Aridity spanning both rainfall seasons at 4.1 ka may help to explain some of the observed archaeological shifts. Read more
Volatile organic compounds and ozone in Rocky Mountain National Park during FRAPPÉ Atmospheric Chemistry and Physics DOI 10.5194/acp-19-499-2019 14 January 2019 Rocky Mountain National Park experiences high ozone concentrations that can exceed the National Ambient Air Quality Standard. As part of the FRAPPÉ field campaign, a suite of volatile organic compounds were measured to characterize the sources of ozone precursors that contribute to high ozone in the park. These measurements indicate emissions from the Front Range in Colorado tied to oil and gas operations, urban areas, and the stratosphere contribute to episodes of elevated ozone. Read more
Atmospheric histories, growth rates and solubilities in seawater and other natural waters of the potential transient tracers HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116 Ocean Science DOI 10.5194/os-15-33-2019 11 January 2019 Use of CFCs as oceanic transient tracers is difficult for recently ventilated water masses as their atmospheric mole fractions have been decreasing. To explore novel tracers, we synthesized consistent annual mean atmospheric histories of HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 (CF4) and PFC-116 in both hemispheres and reconstructed their solubility functions in water and seawater. This work is also potentially useful for tracer studies in a range of natural waters. Read more
Structural changes in the shallow and transition branch of the Brewer–Dobson circulation induced by El Niño Atmospheric Chemistry and Physics DOI 10.5194/acp-19-425-2019 11 January 2019 This paper assesses the structural changes in the shallow and transition branches of the BDC induced by El Nino using the Lagrangian model simulations driven by ERAi and JRA-55 combined with MLS observations. We found a clear evidence of a weakening of the transition branch due to an upward shift in the dissipation height of the planetary and gravity waves and a strengthening of the shallow branch due to enhanced GW breaking in the tropics–subtropics and PW breaking at high latitudes. Read more
Refining physical aspects of soil quality and soil health when exploring the effects of soil degradation and climate change on biomass production: an Italian case study SOIL DOI 10.5194/soil-5-1-2019 10 January 2019 This study is restricted to soil physical aspects of soil quality and health with the objective to define procedures with worldwide rather than only regional applicability, reflecting modern developments in soil physical research and focusing on important questions regarding possible effects of soil degradation and climate change. Read more
Exploring the use of underground gravity monitoring to evaluate radar estimates of heavy rainfall Hydrology and Earth System Sciences DOI 10.5194/hess-23-93-2019 8 January 2019 In this study, we explore the use of an underground superconducting gravimeter as a new source of in situ observations for the evaluation of radar-based precipitation estimates. The comparison of radar and gravity time series over 15 years shows that short-duration intense rainfall events cause a rapid decrease in the measured gravity. Rainfall amounts can be derived from this decrease. The gravimeter allows capture of rainfall at a much larger spatial scale than a traditional rain gauge. Read more
The onset of neoglaciation in Iceland and the 4.2 ka event Climate of the Past DOI 10.5194/cp-15-25-2019 8 January 2019 Compositing climate proxies in sediment from seven Iceland lakes documents abrupt summer cooling between 4.5 and 4.0 ka, statistically indistinguishable from 4.2 ka. Although the decline in summer insolation was an important factor, a combination of superposed changes in ocean circulation and explosive Icelandic volcanism were likely responsible for the abrupt perturbation recorded by our proxies. Lake and catchment proxies recovered to a colder equilibrium state following the perturbation. Read more
A shape model of internally mixed soot particles derived from artificial surface tension Atmospheric Measurement Techniques DOI 10.5194/amt-12-107-2019 7 January 2019 We developed a shape model of coated soot particles and created a dataset of their optical properties. To simulate the detailed shape properties of mixtures of soot aggregates and adhered water-soluble substances, we propose a simple model of surface tension derived from the artificial surface potential. The results of some single-scattering properties including lidar backscattering were discussed. Read more
ESD Ideas: Photoelectrochemical carbon removal as negative emission technology Earth System Dynamics DOI 10.5194/esd-10-1-2019 4 January 2019 Current CO2 emission rates are incompatible with the 2 °C target for global warming. Negative emission technologies are therefore an important basis for climate policy scenarios. We show that photoelectrochemical CO2 reduction might be a viable, high-efficiency alternative to biomass-based approaches, which reduce competition for arable land. To develop them, chemical reactions have to be optimized for CO2 removal, which deviates from energetic efficiency optimization in solar fuel applications. Read more
What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? Climate of the Past DOI 10.5194/cp-14-2053-2018 20 December 2018 Proxy data on climate variations contain noise from many sources and, for reliable estimates, we need to determine those temporal scales at which the climate signal in the proxy record dominates the noise. We developed a method to derive timescale-dependent estimates of temperature proxy signal-to-noise ratios, which we apply and discuss in the context of Antarctic ice-core records but which in general are applicable to a large set of palaeoclimate records. Read more
Photochemical box modelling of volcanic SO2 oxidation: isotopic constraints Atmospheric Chemistry and Physics DOI 10.5194/acp-18-17909-2018 18 December 2018 Volcanic sulfur can have climatic impacts for the planet via sulfate aerosol formation, leading also to pollution events. We provide model constraints on tropospheric volcanic sulfate formation, with implications for its lifetime and impacts on regional air quality. Oxygen isotope investigations from our model suggest that in the poor tropospheric plumes of halogens, the O2/TMI sulfur oxidation pathway might significantly control sulfate production. The produced sulfate has no isotopic anomaly. Read more
Retreat of Thwaites Glacier, West Antarctica, over the next 100 years using various ice flow models, ice shelf melt scenarios and basal friction laws The Cryosphere DOI 10.5194/tc-12-3861-2018 11 December 2018 Thwaites Glacier, West Antarctica, has experienced rapid grounding line retreat and mass loss in the past decades. In this study, we simulate the evolution of Thwaites Glacier over the next century using different model configurations. Overall, we estimate a 5 mm contribution to global sea level rise from Thwaites Glacier in the next 30 years. However, a 300% uncertainty is found over the next 100 years, ranging from 14 to 42 mm, depending on the model setup. Read more
The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe Atmospheric Chemistry and Physics DOI 10.5194/acp-18-17545-2018 11 December 2018 The impact of desert dust on cloud formation is investigated for a major Saharan dust event over Europe by interactive regional dust modeling. Dust particles are very efficient ice-nucleating particles promoting the formation of ice crystals in clouds. The simulations show that the observed extensive cirrus development was likely related to the above-average dust load. The interactive dust–cloud feedback in the model significantly improves the agreement with aircraft and satellite observations. Read more
ESM-SnowMIP: assessing snow models and quantifying snow-related climate feedbacks Geoscientific Model Development DOI 10.5194/gmd-11-5027-2018 10 December 2018 This paper provides an overview of a coordinated international experiment to determine the strengths and weaknesses in how climate models treat snow. The models will be assessed at point locations using high-quality reference measurements and globally using satellite-derived datasets. How well climate models simulate snow-related processes is important because changing snow cover is an important part of the global climate system and provides an important freshwater resource for human use. Read more
Hydro-climatic variability in the southwestern Indian Ocean between 6000 and 3000 years ago Climate of the Past DOI 10.5194/cp-14-1881-2018 7 December 2018 The 4.2 ka eventbetween 4.2 and 3.9 ka has been widely discussed in the Northern Hemsiphere but less reported in the Southern Hemisphere. Here, we use speleothem records from Rodrigues in the southwestern Indian Ocean spanning from 6000 to 3000 years ago to investigate the regional hydro-climatic variability. Our records show no evidence for an unusual climate anomaly between 4.2 and 3.9 ka. Instead, it shows a multi-centennial drought between 3.9 and 3.5 ka. Read more
Light absorption by marine cyanobacteria affects tropical climate mean state and variability Earth System Dynamics DOI 10.5194/esd-9-1283-2018 5 December 2018 We use an Earth system model to study the effects of light absorption by marine cyanobacteria on climate. We find that cyanobacteria have a considerable cooling effect on tropical SST with implications for ocean and atmosphere circulation patterns as well as for climate variability. The results indicate the importance of considering phytoplankton light absorption in climate models, and specifically highlight the role of cyanobacteria due to their regulative effect on tropical SST and climate. Read more
Seasonal to decadal variability in ice discharge from the Greenland Ice Sheet The Cryosphere DOI 10.5194/tc-12-3813-2018 3 December 2018 We derive the first continuous record of total ice discharged from all large Greenland outlet glaciers over the 2000–2016 period, resolving a distinct pattern of seasonal variability. We compare these results to glacier retreat and meltwater runoff and find that while runoff has a limited impact on ice discharge in summer, long-term changes in discharge are highly correlated to retreat. These results help to better understand Greenland outlet glacier sensitivity over a range of timescales. Read more
Cold-to-warm flow regime transition in snow avalanches The Cryosphere DOI 10.5194/tc-12-3759-2018 30 November 2018 Snow avalanches show complicated flow behaviour, characterized by several flow regimes which coexist in one avalanche. In this work, we analyse flow regime transitions where a powder snow avalanche transforms into a plug flow avalanche by incorporating warm snow due to entrainment. Prediction of such a transition is very important for hazard mitigation, as the efficiency of protection dams are strongly dependent on the flow regime, and our results should be incorporated into avalanche models. Read more
Solar wind and kinetic heliophysics Annales Geophysicae DOI 10.5194/angeo-36-1607-2018 30 November 2018 This paper originated from the lecture I gave as the Hannes Alfvén medalist at the EGU General Assembly in Vienna in spring 2018. The paper reviews various aspects of modern solar wind physics and elucidates the role Alfvén waves play in solar wind acceleration and turbulence, which prevail in the low corona and inner heliosphere. Our understanding of the solar wind has recently made considerable progress based on remote sensing, in situ measurements, kinetic simulation and fluid modeling. Read more
What can seabirds tell us about the tide? Ocean Science DOI 10.5194/os-14-1483-2018 29 November 2018 This paper describes a feasibility study carried out to determine if information gathered for one discipline could berepurposedto provide insight in another. Data gathered during a study of bird distribution were used to investigate whether these same data could be used to measure tidal current velocities and direction. The paper concludes that there is potential to use GPS-tagged birds asdrifters of opportunityand that interdisciplinary sharing of data can provide additional insight. Read more
Field survey of Typhoon Hato (2017) and a comparison with storm surge modeling in Macau Natural Hazards and Earth System Sciences DOI 10.5194/nhess-18-3167-2018 29 November 2018 Typhoon Hato was one of the most damaging natural disaster events in the western Pacific region in 2017. It caused the the worst flooding in Macau since its instrumental records began in 1925. We present a high-resolution survey map recording inundation depths and distances at 278 sites in Macau. We provide a series of inundation maps under different tidal and sea levels. The maps that highlight adaptive strategies are essential in order to keep up with the pace of rising sea level. Read more
Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle Climate of the Past DOI 10.5194/cp-14-1819-2018 28 November 2018 A data-based reconstruction of carbon-bearing deep-sea sediment shows significant changes in the global burial rate over the last glacial cycle. We calculate the impact of these deep-sea changes, as well as hypothetical changes in continental shelf burial and volcanic outgassing. Our results imply that these geological fluxes had a significant impact on ocean chemistry and the global carbon isotopic ratio, and that the natural carbon cycle was not in steady state during the Holocene. Read more
Connecting the Greenland ice-core and U/Th timescales via cosmogenic radionuclides: testing the synchroneity of Dansgaard–Oeschger events Climate of the Past DOI 10.5194/cp-14-1755-2018 20 November 2018 The last glacial period was characterized by a number of rapid climate changes seen, for example, as abrupt warmings in Greenland and changes in monsoon rainfall intensity. However, due to chronological uncertainties it is challenging to know how tightly coupled these changes were. Here we exploit cosmogenic signals caused by changes in the Sun and Earth magnetic fields to link different climate archives and improve our understanding of the dynamics of abrupt climate change. Read more
Mesospheric bores at southern midlatitudes observed by ISS-IMAP/VISI: a first report of an undulating wave front Atmospheric Chemistry and Physics DOI 10.5194/acp-18-16399-2018 19 November 2018 Spatial structures of wave disturbances in the upper atmosphere were investigated with space-borne imaging from the International Space Station. The wave disturbance occurred around an altitude of 100 km, and is called a mesospheric bore. The large-scale structure of mesospheric bores has not been fully captured by previous ground-based imagers, but the space-borne imaging captured a bore with a wide field of view, and showed that bores can have a large undulating wave front as long as 2000 km. Read more
Distribution and cycling of terrigenous dissolved organic carbon in peatland-draining rivers and coastal waters of Sarawak, Borneo Biogeosciences DOI 10.5194/bg-15-6847-2018 16 November 2018 The carbon cycle is a key control for the Earth’s climate. Every year rivers deliver a lot of organic carbon to coastal seas, but we do not know what happens to this carbon, particularly in the tropics. We show that rivers in Borneo deliver carbon from peat swamps to the sea with at most minimal biological or chemical alteration in estuaries, but sunlight can rapidly oxidise this carbon to CO2. This means that south-east Asian seas are likely hotspots of terrestrial carbon decomposition. Read more
Global phosphorus recovery from wastewater for agricultural reuse Hydrology and Earth System Sciences DOI 10.5194/hess-22-5781-2018 12 November 2018 Phosphorus (P) is important to global food security. Thus it is concerning that natural P reserves are predicted to deplete within the century. Here we explore the potential of P recovery from wastewater (WW) at global scale. We identify high production and demand sites to determine optimal market prices and trade flows. We show that 20% of the agricultural demand can be met, yet only 4 % can be met economically. Nonetheless, this recovery stimulates circular economic development in WW treatment. Read more
ESD Ideas: The stochastic climate model shows that underestimated Holocene trends and variability represent two sides of the same coin Earth System Dynamics DOI 10.5194/esd-9-1279-2018 12 November 2018 Long-term sea surface temperature trends and variability are underestimated in models compared to paleoclimate data. The idea is presented that the trends and variability are related, which is elaborated in a conceptual model framework. The temperature spectrum can be used to estimate the timescale-dependent climate sensitivity. Read more
A 900-year New England temperature reconstruction from in situ seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs) Climate of the Past DOI 10.5194/cp-14-1653-2018 7 November 2018 We measured biomarker production over a year in a small inland lake in the northeastern USA. Understanding biomarkers in the modern environment helps us improve reconstructions of past climate from lake sediment records. We use these results to interpret a 900-year decadally resolved temperature record from this lake. Our record highlights multi-decadal oscillations in temperature superimposed on a long-term cooling trend, providing novel insight into climate dynamics of the region. Read more
Spatial assessments of soil organic carbon for stakeholder decision-making – a case study from Kenya SOIL DOI 10.5194/soil-4-259-2018 7 November 2018 Land degradation impacts the health and livelihoods of about 1.5 billion people worldwide. The state of the environment and food security are strongly interlinked in tropical landscapes. This paper demonstrates the integration of soil organic carbon (SOC) and land health maps with socioeconomic datasets into an online, open-access platform called the Resilience Diagnostic and Decision Support Tool for Turkana County in Kenya. Read more
Cascading transitions in the climate system Earth System Dynamics DOI 10.5194/esd-9-1243-2018 6 November 2018 We introduce a framework of cascading tipping, i.e. a sequence of abrupt transitions occurring because a transition in one system affects the background conditions of another system. Using bifurcation theory, various types of these events are considered and early warning indicators are suggested. An illustration of such an event is found in a conceptual model, coupling the North Atlantic Ocean with the equatorial Pacific. This demonstrates the possibility of events such as this in nature. Read more
Predominance of methanogens over methanotrophs in rewetted fens characterized by high methane emissions Biogeosciences DOI 10.5194/bg-15-6519-2018 6 November 2018 Rewetting drained peatlands may lead to prolonged emission of the greenhouse gas methane, but the underlying factors are not well described. In this study, we found two rewetted fens with known high methane fluxes had a high ratio of microbial methane producers to methane consumers and a low abundance of methane consumers compared to pristine wetlands. We therefore suggest abundances of methane-cycling microbes as potential indicators for prolonged high methane emissions in rewetted peatlands. Read more
Towards risk-based flood management in highly productive paddy rice cultivation – concept development and application to the Mekong Delta Natural Hazards and Earth System Sciences DOI 10.5194/nhess-18-2859-2018 5 November 2018 In this study we provide an estimation of flood damages and risks to rice cultivation in the Mekong Delta. The derived modelling concept explicitly takes plant phenomenology and timing of floods in a probabilistic modelling framework into account. This results in spatially explicit flood risk maps to rice cultivation, quantified as expected annual damage. Furthermore, the changes in flood risk of two land-use scenarios were estimated and discussed. Read more
The influence of upper-plate advance and erosion on overriding plate deformation in orogen syntaxes Solid Earth DOI 10.5194/se-9-1207-2018 5 November 2018 In this modeling study, we investigate rock uplift at plate corners (syntaxes). These are characterized by a unique bent geometry at subduction zones and exhibit some of the world’s highest rock uplift rates. We find that the style of deformation changes above the plate’s bent section and that active subduction is necessary to generate an isolated region of rapid uplift. Strong erosion there localizes uplift on even smaller scales, suggesting both tectonic and surface processes are important. Read more