Interpretability of negative latent heat fluxes from eddy covariance measurements in dry conditions Biogeosciences DOI 10.5194/bg-21-2051-2024 26 April 2024 Porous materials are known to reversibly trap water from the air, even at low humidity. However, this behavior is poorly understood for soils. In this analysis, we test whether eddy covariance is able to measure the so-called adsorption of atmospheric water vapor by soils. We find that this flux occurs frequently during dry nights in a Mediterranean ecosystem, while EC detects downwardly directed vapor fluxes. These results can help to map moisture uptake globally. Read more
Carbon budget concept and its deviation through the pulse response lens Earth System Dynamics DOI 10.5194/esd-15-387-2024 22 April 2024 The carbon budget approach is based on a close linear relationship between the global temperature and cumulative emissions. This article reinterprets the carbon budget approach through the lens of the temperature response to an emission pulse in the role of a Green’s function, or as a generalization of TCRE. It shows that inspecting the simple model’s pulse response allows for a prediction of deviations for any possible emission scenario and derivation of a nonlinear carbon budget equation. Read more
Quantitative imaging of carbon dioxide plumes using a ground-based shortwave infrared spectral camera Atmospheric Measurement Techniques DOI 10.5194/amt-17-2257-2024 19 April 2024 Imaging carbon dioxide (CO2) plumes of anthropogenic sources from planes and satellites has proven valuable for detecting emitters and monitoring climate mitigation efforts. We present the first images of CO2 plumes taken with a ground-based spectral camera, observing a coal-fired power plant as a validation target. We develop a technique to find the source emission strength with an hourly resolution, which reasonably agrees with the expected emissions under favorable conditions. Read more
HydroFATE (v1): a high-resolution contaminant fate model for the global river system Geoscientific Model Development DOI 10.5194/gmd-17-2877-2024 16 April 2024 Treated and untreated wastewaters are sources of contaminants of emerging concern. HydroFATE, a new global model, estimates their concentrations in surface waters, identifying streams that are most at risk and guiding monitoring/mitigation efforts to safeguard aquatic ecosystems and human health. Model predictions were validated against field measurements of the antibiotic sulfamethoxazole, with predicted concentrations exceeding ecological thresholds in more than 400 000 km of rivers worldwide. Read more
Rates of palaeoecological change can inform ecosystem restoration Biogeosciences DOI 10.5194/bg-21-1629-2024 12 April 2024 Rate-of-change records based on compositional data are ambiguous as they may rise irrespective of the underlying trajectory of ecosystems. We emphasize the importance of characterizing both the direction and the rate of palaeoecological changes in terms of key features of ecosystems rather than solely on community composition. Past accelerations of community transformation may document the potential of ecosystems to rapidly recover important ecological attributes and functions. Read more
Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates The Cryosphere DOI 10.5194/tc-18-1467-2024 10 April 2024 This study uses airborne radar data and satellite imagery to map mountainous topography hidden beneath the Greenland Ice Sheet. We find that the landscape records the former extent and configuration of ice masses that were restricted to areas of high topography. Computer models of ice flow indicate that valley glaciers eroded this landscape millions of years ago when local air temperatures were at least 4 °C higher than today and Greenland’s ice volume was < 10 % of that of the modern ice sheet. Read more
Minimizing the effects of Pb loss in detrital and igneous U–Pb zircon geochronology by CA-LA-ICP-MS Geochronology DOI 10.5194/gchron-6-89-2024 8 April 2024 Chemical abrasion (CA) is a technique that reduces or eliminates the effects of Pb loss in zircon U–Pb geochronology. However, CA has yet to be applied to large-n detrital zircon (DZ) analyses. We show that CA does not negatively impact or systematically bias U–Pb dates, improves the resolution of age populations defined by 206Pb/238U dates, and increases the percentage of concordant analyses in age populations defined by 207Pb/206Pb dates. Read more
Extreme melting at Greenland’s largest floating ice tongue The Cryosphere DOI 10.5194/tc-18-1333-2024 5 April 2024 The 79° North Glacier in Greenland has experienced significant changes over the last decades. Due to extreme melt rates, the ice has thinned significantly in the vicinity of the grounding line, where a large subglacial channel has formed since 2010. We attribute these changes to warm ocean currents and increased subglacial discharge from surface melt. However, basal melting has decreased since 2018, indicating colder water inflow into the cavity below the glacier. Read more
Solar radiation modification challenges decarbonization with renewable solar energy Earth System Dynamics DOI 10.5194/esd-15-307-2024 3 April 2024 Most solar radiation modification (SRM) simulations assume no physical coupling between mitigation and SRM. We analyze the impact of SRM on photovoltaic (PV) and concentrated solar power (CSP) and find that almost all regions have reduced PV and CSP potential compared to a mitigated or unmitigated scenario, especially in the middle and high latitudes. This suggests that SRM could pose challenges for meeting energy demands with solar renewable resources. Read more
Possible role of anthropogenic climate change in the record-breaking 2020 Lake Victoria levels and floods Earth System Dynamics DOI 10.5194/esd-15-225-2024 27 March 2024 Heavy rainfall in eastern Africa between late 2019 and mid 2020 caused devastating floods and landslides and drove the levels of Lake Victoria to a record-breaking maximum in May 2020. In this study, we characterize the spatial extent and impacts of the floods in the Lake Victoria basin and investigate how human-induced climate change influenced the probability and intensity of the record-breaking lake levels and flooding by applying a multi-model extreme event attribution methodology. Read more
A past and present perspective on the European summer vapor pressure deficit Climate of the Past DOI 10.5194/cp-20-573-2024 25 March 2024 The main aim of this paper is to present the summer vapor pressure deficit (VPD) reconstruction dataset for the last 400 years over Europe based on δ18O records by using a random forest approach. We provide both a spatial and a temporal long-term perspective on the past summer VPD and new insights into the relationship between summer VPD and large-scale atmospheric circulation. This is the first gridded reconstruction of the European summer VPD over the past 400 years. Read more
Distinct oxygenation modes of the Gulf of Oman over the past 43 000 years – a multi-proxy approach Biogeosciences DOI 10.5194/bg-21-1477-2024 22 March 2024 We analyse benthic foraminifera, nitrogen isotopes and lipids in a sediment core from the Gulf of Oman to investigate how the oxygen minimum zone (OMZ) and bottom water (BW) oxygenation have reacted to climatic changes since 43 ka. The OMZ and BW deoxygenation was strong during the Holocene, but the OMZ was well ventilated during the LGM period. We found an unstable mode of oscillating oxygenation states, from moderately oxygenated in cold stadials to deoxygenated in warm interstadials in MIS 3. Read more
Observations of cyanogen bromide (BrCN) in the global troposphere and their relation to polar surface O3 destruction Atmospheric Chemistry and Physics DOI 10.5194/acp-24-3421-2024 20 March 2024 We measured cyanogen bromide (BrCN) in the troposphere for the first time. BrCN is a product of the same active bromine chemistry that destroys ozone and removes mercury in polar surface environments and is a previously unrecognized sink for active Br compounds. BrCN has an apparent lifetime against heterogeneous loss in the range 1–10 d, so it serves as a cumulative marker of Br-radical chemistry. Accounting for BrCN chemistry is an important part of understanding polar Br cycling. Read more
First validation of high-resolution satellite-derived methane emissions from an active gas leak in the UK Atmospheric Measurement Techniques DOI 10.5194/amt-17-1599-2024 18 March 2024 We provide the first validation of the satellite-derived emission estimates using surface-based mobile greenhouse gas surveys of an active gas leak detected near Cheltenham, UK. GHGSat’s emission estimates broadly agree with the surface-based mobile survey and steps were taken to fix the leak, highlighting the importance of satellite data in identifying emissions and helping to reduce our human impact on climate change. Read more
Minimum-variance-based outlier detection method using forward-search model error in geodetic networks Geoscientific Model Development DOI 10.5194/gmd-17-2187-2024 15 March 2024 This study introduces a novel approach to outlier detection in geodetic networks, challenging conventional and robust methods. By treating outliers as unknown parameters within the Gauss–Markov model and exploring numerous outlier combinations, this approach prioritizes minimal variance and eliminates iteration dependencies. The mean success rate (MSR) comparisons highlight its effectiveness, improving the MSR by 40–45 % for multiple outliers. Read more
Ideas and perspectives: Sensing energy and matter fluxes in a biota-dominated Patagonian landscape through environmental seismology – introducing the Pumalín Critical Zone Observatory Biogeosciences DOI 10.5194/bg-21-1583-2024 15 March 2024 Coastal temperate rainforests, among Earth’s carbon richest biomes, are systematically underrepresented in the global network of critical zone observatories (CZOs). Introducing here a first CZO in the heart of the Patagonian rainforest, Chile, we investigate carbon sink functioning, biota-driven landscape evolution, fluxes of matter and energy, and disturbance regimes. We invite the community to join us in cross-disciplinary collaboration to advance science in this particular environment. Read more
Hemispherically symmetric strategies for stratospheric aerosol injection Earth System Dynamics DOI 10.5194/esd-15-191-2024 13 March 2024 Injecting SO2 into the lower stratosphere can temporarily reduce global mean temperature and mitigate some risks associated with climate change, but injecting it at different latitudes and seasons would have different impacts. This study introduces new stratospheric aerosol injection (SAI) strategies and explores the importance of the choice of SAI strategy, demonstrating that it notably affects the distribution of aerosol cloud, injection efficiency, and various surface climate impacts. Read more
Regime shifts in Arctic terrestrial hydrology manifested from impacts of climate warming The Cryosphere DOI 10.5194/tc-18-1033-2024 6 March 2024 Flows of water, carbon, and materials by Arctic rivers are being altered by climate warming. We used simulations from a permafrost hydrology model to investigate future changes in quantities influencing river exports. By 2100 Arctic rivers will receive more runoff from the far north where abundant soil carbon can leach in. More water will enter them via subsurface pathways particularly in summer and autumn. An enhanced water cycle and permafrost thaw are changing river flows to coastal areas. Read more
A global compilation of diatom silica oxygen isotope records from lake sediment – trends and implications for climate reconstruction Climate of the Past DOI 10.5194/cp-20-363-2024 26 February 2024 This paper presents the first comprehensive compilation of diatom oxygen isotope records in lake sediments (δ18OBSi), supported by lake basin parameters. We infer the spatial and temporal coverage of δ18OBSi records and discuss common hemispheric trends on centennial and millennial timescales. Key results are common patterns for hydrologically open lakes in Northern Hemisphere extratropical regions during the Holocene corresponding to known climatic epochs, i.e. the Holocene Thermal Maximum. Read more
Explaining the green volcanic sunsets after the 1883 eruption of Krakatoa Atmospheric Chemistry and Physics DOI 10.5194/acp-24-2415-2024 23 February 2024 It is well known that volcanic eruptions strongly affect the colours of the twilight sky. Typically, volcanic eruptions lead to enhanced reddish and violet twilight colours. In rare cases, however, volcanic eruptions can also lead to green sunsets. This study provides an explanation for the occurrence of these unusual green sunsets based on simulations with a radiative transfer model. Green volcanic sunsets require a sufficient stratospheric aerosol optical depth and specific aerosol sizes. Read more