Reconstructing Holocene temperatures in time and space using paleoclimate data assimilation Climate of the Past DOI 10.5194/cp-18-2599-2022 15 February 2023 To look at climate over the past 12 000 years, we reconstruct spatial temperature using natural climate archives and information from model simulations. Our results show mild global mean warmth around 6000 years ago, which differs somewhat from past reconstructions. Undiagnosed seasonal biases in the data could explain some of the observed temperature change, but this still would not explain the large difference between many reconstructions and climate models over this period. Read more
Solar wind magnetic holes can cross the bow shock and enter the magnetosheath Annales Geophysicae DOI 10.5194/angeo-40-687-2022 13 February 2023 Magnetic holes are curious localized dropouts of magnetic field strength in the solar wind (the flow of ionized gas continuously streaming out from the sun). In this paper we show that these magnetic holes can cross the bow shock (where the solar wind brake down to subsonic velocity) and enter the region close to Earth’s magnetosphere. These structures may therefore represent a new type of non-uniform solar wind–magnetosphere interaction. Read more
Rapid attribution analysis of the extraordinary heat wave on the Pacific coast of the US and Canada in June 2021 Earth System Dynamics DOI 10.5194/esd-13-1689-2022 10 February 2023 In June 2021, the Pacific Northwest of the US and Canada saw record temperatures far exceeding those previously observed. This attribution study found such a severe heat wave would have been virtually impossible without human-induced climate change. Assuming no nonlinear interactions, such events have become at least 150 times more common, are about 2 ℃ hotter and will become even more common as warming continues. Therefore, adaptation and mitigation are urgently needed to prepare society. Read more
Validation of the Aeolus L2B wind product with airborne wind lidar measurements in the polar North Atlantic region and in the tropics Atmospheric Measurement Techniques DOI 10.5194/amt-15-7049-2022 8 February 2023 In August 2018, the first wind lidar Aeolus was launched into space and has since then been providing data of the global wind field. The primary goal of Aeolus was the improvement of numerical weather prediction. To verify the quality of Aeolus wind data, DLR performed four airborne validation campaigns with two wind lidar systems. In this paper, we report on results from the two later campaigns, performed in Iceland and the tropics. Read more
Estimating emissions of methane consistent with atmospheric measurements of methane and δ13C of methane Atmospheric Chemistry and Physics DOI 10.5194/acp-22-15351-2022 6 February 2023 Atmospheric methane (CH4) has been growing steadily since 2007 for reasons that are not well understood. Here we determine sources of methane using a technique informed by atmospheric measurements of CH₄ and its isotopologue 13CH4. Measurements of 13CH4 provide for better separation of microbial, fossil, and fire sources of methane than CH4 measurements alone. Compared to previous assessments such as the Global Carbon Project, we find a larger microbial contribution to the post-2007 increase. Read more
Size, shape and orientation matter: fast and semi-automatic measurement of grain geometries from 3D point clouds Earth Surface Dynamics DOI 10.5194/esurf-10-1211-2022 3 February 2023 The morphology and size of sediments influence erosion efficiency, sediment transport and the quality of aquatic ecosystem. In turn, the spatial evolution of sediment size provides information on the past dynamics of erosion and sediment transport. We have developed a new software which semi-automatically identifies and measures sediments based on 3D point clouds. This software is fast and efficient, offering a new avenue to measure the geometrical properties of large numbers of sediment grains. Read more
Evidence of localised Amazon rainforest dieback in CMIP6 models Earth System Dynamics DOI 10.5194/esd-13-1667-2022 1 February 2023 Despite little evidence of regional Amazon rainforest dieback, many localised abrupt dieback events are observed in the latest state-of-the-art global climate models under anthropogenic climate change. The detected dieback events would still cause severe consequences for local communities and ecosystems. This study suggests that 7±5 % of the northern South America region would experience abrupt downward shifts in vegetation carbon for every degree of global warming past 1.5 °C. Read more
The evolution and dynamics of the Hunga Tonga–Hunga Ha’apai sulfate aerosol plume in the stratosphere Atmospheric Chemistry and Physics DOI 10.5194/acp-22-14957-2022 30 January 2023 The long-duration atmospheric impact of the Tonga eruption in January 2022 is a plume of water and sulfate aerosols in the stratosphere that persisted for more than 6 months. We study this evolution using several satellite instruments and analyse the unusual behaviour of this plume as sulfates and water first moved down rapidly and then separated into two layers. We also report the self-organization in compact and long-lived patches. Read more
Exploring TikTok as a promising platform for geoscience communication Geoscience Communication DOI 10.5194/gc-5-363-2022 27 January 2023 To determine the best strategies for geoscience communication on TikTok, we created a TikTok account called “Terra Explore”. We produced 48 educational geoscience videos and evaluated each video’s performance. Our most-viewed videos received nearly all of their views from TikTok’s algorithmic recommendation feed, and the videos that received the most views were related to a recent newsworthy event (e.g., earthquake) or explained the geology of a recognizable area. Read more
Internal tides off the Amazon shelf during two contrasted seasons: interactions with background circulation and SSH imprints Ocean Science DOI 10.5194/os-18-1591-2022 25 January 2023 This high-resolution model-based study investigates the variability in the generation, propagation, and sea height signature (SSH) of the internal tide off the Amazon shelf during two contrasted seasons. ITs propagate further north during the season characterized by weak currents and mesoscale eddies and a shallow and strong pycnocline. IT imprints on SSH dominate those of the geostrophic motion for horizontal scales below 200 km; moreover, the SSH is mainly incoherent below 70 km. Read more
Global biomass burning fuel consumption and emissions at 500m spatial resolution based on the Global Fire Emissions Database (GFED) Geoscientific Model Development DOI 10.5194/gmd-15-8411-2022 23 January 2023 We present a global fire emission model based on the GFED model framework with a spatial resolution of 500 m. The higher resolution allowed for a more detailed representation of spatial heterogeneity in fuels and emissions. Specific modules were developed to model, for example, emissions from fire-related forest loss and belowground burning. Results from the 500 m model were compared to GFED4s, showing that global emissions were relatively similar but that spatial differences were substantial. Read more
Building confidence in STEM students through breaking (unseen) barriers Geoscience Communication DOI 10.5194/gc-5-355-2022 20 January 2023 Science, technology, engineering, and maths subjects have historically struggled to be inclusive to students from diverse backgrounds. We outline here an outreach course designed to improve critical thinking for people in prison. Based on course feedback, we share advice for working with students who do not engage in formal education – specifically those who have low self-confidence. We focus on how to create a classroom dynamic that is accessible, inclusive, and relatable to all students. Read more
The climate impact of hydrogen-powered hypersonic transport Atmospheric Chemistry and Physics DOI 10.5194/acp-22-14323-2022 18 January 2023 Very fast aircraft can travel long distances in extremely short times and can fly at high altitudes (15 to 35 km). These aircraft emit water vapour, nitrogen oxides, and hydrogen. Water vapour emissions remain for months to several years at these altitudes and have an important impact on temperature. We investigate two aircraft fleets flying at 26 and 35 km. Ozone is depleted more, and the water vapour perturbation and temperature change are larger for the aircraft flying at 35 km. Read more
Highest methane concentrations in an Arctic river linked to local terrestrial inputs Biogeosciences DOI 10.5194/bg-19-5059-2022 16 January 2023 Permafrost thaw releases methane that can be emitted into the atmosphere or transported by Arctic rivers. Methane measurements are lacking in large Arctic river regions. In the Kolyma River (northeast Siberia), we measured dissolved methane to map its distribution with great spatial detail. The river’s edge and river junctions had the highest methane concentrations compared to other river areas. Microbial communities in the river showed that the river’s methane likely is from the adjacent land. Read more
Improving interpretation of sea-level projections through a machine-learning-based local explanation approach The Cryosphere DOI 10.5194/tc-16-4637-2022 13 January 2023 To improve the interpretability of process-based projections of the sea-level contribution from land ice components, we apply the machine-learning-based “SHapley Additive exPlanations” approach to a subset of a multi-model ensemble study for the Greenland ice sheet. This allows us to quantify the influence of particular modelling decisions (related to numerical implementation, initial conditions, or parametrisation of ice-sheet processes) directly in terms of sea-level change contribution. Read more
Not all types of secondary organic aerosol mix: two phases observed when mixing different secondary organic aerosol types Atmospheric Chemistry and Physics DOI 10.5194/acp-22-13783-2022 11 January 2023 The number of condensed phases in mixtures of different secondary organic aerosol (SOA) types determines their impact on air quality and climate. Here we observe the number of phases in individual particles that contain mixtures of two different types of SOA. We find that SOA mixtures can form one- or two-phase particles, depending on the difference in the average oxygen-to-carbon (O/C) ratios of the two SOA types that are internally mixed within individual particles. Read more
Dynamics of the Great Oxidation Event from a 3D photochemical–climate model Climate of the Past DOI 10.5194/cp-18-2421-2022 9 January 2023 In the context of understanding the 3D photochemical effect on the Earth’s oxygenation that happened around 2.4 Ga, we developed a 3D photochemical–climate model to investigate the possible impact of atmospheric circulation and the coupling between the climate and the dynamics of oxidation. We show that the diurnal, seasonal and transport variations do not bring significant changes compared to 1D models. Nevertheless, we highlight a temperature dependence for atmospheric photochemical losses. Read more
Is it possible to estimate aerosol optical depth from historic colour paintings? Climate of the Past DOI 10.5194/cp-18-2345-2022 6 January 2023 This study investigates the possibility of inferring information on aerosol optical depth from photographs of historic paintings. The idea – which has been applied in previous studies – is very interesting because it would provide an archive of the atmospheric aerosol loading covering many centuries. We show that twilight colours depend not only on the aerosol optical thickness, but also on several other parameters, making a quantitative estimate of aerosol optical depth very difficult. Read more
Exceptional freshening and cooling in the eastern subpolar North Atlantic caused by reduced Labrador Sea surface heat loss Ocean Science DOI 10.5194/os-18-1507-2022 4 January 2023 Observations of the eastern subpolar North Atlantic in the 2010s show exceptional freshening and cooling of the upper ocean, peaking in 2016 with the lowest salinities recorded for 120 years. Using results from a high-resolution ocean model, supported by observations, we propose that the leading cause is reduced surface cooling over the preceding decade in the Labrador Sea, leading to increased outflow of less dense water and so to freshening and cooling of the eastern subpolar North Atlantic. Read more
Opinion: Coordinated development of emission inventories for climate forcers and air pollutants Atmospheric Chemistry and Physics DOI 10.5194/acp-22-13201-2022 2 January 2023 Emissions into the atmosphere of greenhouse gases (GHGs) and air pollutants, quantified in emission inventories, impact human health, ecosystems, and the climate. We review how air pollutant and GHG inventory activities have historically been structured and their different uses and requirements. We discuss the benefits of increasing coordination between air pollutant and GHG inventory development efforts, but also caution that there are differences in appropriate methodologies and applications. Read more