The satellite chlorophyll signature of Lagrangian eddy trapping varies regionally and seasonally within a subtropical gyre Ocean Science DOI 10.5194/os-21-1141-2025 30 June 2025 Eddies are rotating ocean vortices up to hundreds of kilometers in diameter that stimulate phytoplankton blooms. We used satellite data and simulations of currents to examine the effect of eddy trapping strength on phytoplankton concentration in the open North Pacific Ocean. Coherent eddies trap phytoplankton, while "leaky" ones have lower concentrations because they mix with surrounding waters. However, contrary to previous theory, eddy-trapped blooms are more prominent in southern latitudes. Read more
Long-term prediction of the Gulf Stream meander using OceanNet: a principled neural-operator-based digital twin Ocean Science DOI 10.5194/os-21-1065-2025 20 June 2025 The Gulf Stream is a prominent oceanic feature in the northwestern Atlantic Ocean that influences weather patterns in the Northern Hemisphere and is notoriously difficult to predict. We present a machine learning model, OceanNet, to predict the position of the Gulf Stream months in advance. OceanNet is able to perform a 120 d prediction 4 000 000 times faster than traditional methods of ocean modeling with great accuracy. Read more
Using 3D observations with high spatio-temporal resolution to calibrate and evaluate a process-focused cellular automaton model of soil erosion by water SOIL DOI 10.5194/soil-11-413-2025 16 June 2025 This study develops a new method to improve the calibration and evaluation of models that predict soil erosion by water. By using advanced imaging techniques, we can capture detailed changes in the soil surface over time. This helps improve models that forecast erosion, especially as climate change creates new and unpredictable conditions. Our findings highlight the need for more precise tools to better model erosion of our land and environment in the future. Read more
The potential of observing atmospheric rivers with Global Navigation Satellite System (GNSS) radio occultation Atmospheric Measurement Techniques DOI 10.5194/amt-18-2481-2025 12 June 2025 The study investigates using Global Navigation Satellite System Radio Occultation (GNSS-RO) to analyze the vertical structure of humidity in atmospheric rivers (ARs). Specific humidity and integrated water vapor from the COSMIC Data Analysis and Archive Center (CDAAC) and the Wegener Center (WEGC) are compared with the Special Sensor Microwave Imager/Sounder (SSMIS), showing that GNSS-RO adds vertically resolved data. Despite a slight low bias, combining GNSS-RO and SSMIS improves AR analysis. Read more
Implications of reduced-complexity aerosol thermodynamics on organic aerosol mass concentration and composition over North America Atmospheric Chemistry and Physics DOI 10.5194/acp-25-5773-2025 12 June 2025 We implemented the BAT-VBS (Binary Activity Thermodynamics volatility basis set) aerosol thermodynamics model in the GEOS-Chem chemical transport model to efficiently account for organic aerosol water uptake, nonideal mixing, and impacts on the gas–particle partitioning of semi-volatile organics. Compared to GEOS-Chem's complex (dry) scheme, we show that the BAT-VBS model can predict substantial enhancements in organic aerosol mass concentration at moderate-to-high relative humidity. Read more
GC Insights: Consistency in pyrocartography starts with color Geoscience Communication DOI 10.5194/gc-8-167-2025 11 June 2025 Fire progression maps (FPMs) provide information regarding wildland fire spread (progress) through time to broad audiences. However, information regarding the best use of color to denote fire progression via maps is limited. This can potentially limit a map's ability to effectively communicate information by creating inconsistent messaging and accessibility challenges. Here, I provide color map recommendations to open a discussion towards consistent and accessible fire progression mapping. Read more
Leaping and vortex motion of the shock aurora toward the late evening sector observed on 26 February 2023 Annales Geophysicae DOI 10.5194/angeo-43-303-2025 11 June 2025 Our research explores the shock aurora, which is typically observed on the dayside due to the rapid compression of the Earth's magnetic field. We observed this rare aurora on the nightside, a region where such events are difficult to detect. Using ground-based cameras, we identified new features, including leaping and vortex-like patterns. These findings offer a fresh insight into the interactions between the solar wind and the magnetosphere, enhancing our understanding of space weather and its effects. Read more
Sedimentary ancient DNA insights into foraminiferal diversity near the grounding line in the western Ross Sea, Antarctica Biogeosciences DOI 10.5194/bg-22-2601-2025 6 June 2025 Ancient foraminiferal DNA is studied in five Antarctic cores with sediments up to 25 kyr old. We use a standard and a new, more effective marker, which may become the next standard for paleoenvironmental studies. Much less diverse foraminifera occur on slopes of submarine moraines than in open-marine settings. Soft-walled foraminifera, not found in the fossil record, are especially abundant. There is no foraminiferal DNA in tills, suggesting its destruction during glacial redeposition. Read more
Explaining the period fluctuation of the quasi-biennial oscillation Atmospheric Chemistry and Physics DOI 10.5194/acp-25-5647-2025 6 June 2025 The paper addresses a fundamental but unresolved question about the tropical stratospheric wind oscillation: why does the period of the oscillation fluctuate irregularly? We use global reanalysis data to provide evidence that the oscillation period is primarily modulated by seasonal variations in small-scale atmospheric wave activity. The findings have implications for seasonal and climate predictions. Read more
Mean ocean temperature change and decomposition of the benthic δ18O record over the past 4.5 million years Climate of the Past DOI 10.5194/cp-21-973-2025 3 June 2025 We reconstruct changes in mean ocean temperature (ΔMOT) over the last 4.5 Myr. We find that the ratio of ΔMOT to changes in global mean sea surface temperature was around 0.5 before the Middle Pleistocene transition but was 1 thereafter. We subtract our ΔMOT reconstruction from the global δ18O record to derive the δ18O of seawater. Finally, we develop a theoretical understanding of why the ratio of ΔMOT / ΔGMSST changed over the Plio-Pleistocene. Read more
Quantified ice-nucleating ability of AgI-containing seeding particles in natural clouds Atmospheric Chemistry and Physics DOI 10.5194/acp-25-5387-2025 2 June 2025 We analyzed the ability of silver iodide particles (a commonly used cloud-seeding agent) to form ice crystals in naturally occurring liquid clouds at −5 to −8 °C and found that only ≈ 0.1 %−1 % of particles nucleate ice, with a negative dependence on temperature. By contextualizing our results with previous laboratory studies, we help to bridge the gap between laboratory and field experiments, which also helps to inform future cloud-seeding projects. Read more
Calcium is associated with specific soil organic carbon decomposition products SOIL DOI 10.5194/soil-11-381-2025 20 May 2025 This study shows that calcium (Ca) preserves soil organic carbon (SOC) in acidic soils, challenging beliefs that their interactions were limited to near-neutral or alkaline soils. Using spectromicroscopy, we found that Ca was co-located with a specific fraction of carbon, rich in aromatic and phenolic groups. This association was disrupted when Ca was removed but was reformed during decomposition with added Ca. Overall, this suggests that Ca amendments could enhance SOC stability. Read more
Multifractality of climate networks Nonlinear Processes in Geophysics DOI 10.5194/npg-32-131-2025 15 May 2025 We have developed a systematic approach to study the climate system at multiple scales using climate networks, which have been previously used to study correlations between time series in space at only a single scale. This new approach is used to upscale precipitation climate networks to study the Indian summer monsoon and to analyze strong dependencies between spatial regions, which change with changing scales. Read more
Social sensing a volcanic eruption: application to Kīlauea, 2018 Natural Hazards and Earth System Sciences DOI 10.5194/nhess-25-1681-2025 13 May 2025 Protecting lives and livelihoods during volcanic eruptions is the key challenge in volcanology. Analysing social media usage during volcanic crises can help us better understand the impacts of volcanic eruptions and how warning messages are received and actioned, to eventually better protect those people and their livelihoods. Our work shows how social media data could be used in real time during a volcanic crisis to learn more about volcanic eruptions. Read more
Surficial sediment remobilization by shear between sediment and water above tsunamigenic megathrust ruptures: experimental study Earth Surface Dynamics DOI 10.5194/esurf-13-341-2025 13 May 2025 We propose a new mechanism of co-seismic sediment entrainment induced by shear stress at the sediment–water interface during major subduction earthquakes rupturing to the trench. Physical experiments show that flow velocities consistent with long-period earthquake motions can entrain synthetic marine sediment, and high-frequency vertical shaking can enhance this mobilization. They validate the proposed entrainment mechanism, which opens new avenues for paleoseismology in deep-sea environments. Read more
Cold-water coral mounds are effective carbon sinks in the western Mediterranean Sea Biogeosciences DOI 10.5194/bg-22-2201-2025 9 May 2025 Cold-water coral mounds are large structures on the seabed that are built by corals over thousands of years. They are regarded as carbonate sinks, with a potentially important role in the marine carbon cycle, but more quantitative studies are needed. Using sediment cores, we calculate the amount of carbon that has been stored in two mounds over the last 400 000 years. We provide the first numbers and show that up to 19 times more carbon is accumulated in mounds than on the common seafloor. Read more
Speed-up, slowdown, and redirection of ice flow on neighbouring ice streams in the Pope, Smith, and Kohler region of West Antarctica The Cryosphere DOI 10.5194/tc-19-1725-2025 8 May 2025 We used satellite observations to measure recent changes in ice speed and flow direction in the Pope, Smith, and Kohler region of West Antarctica (2005–2022). We found substantial speed-up on seven ice streams of up to 87 %. However, Kohler West Glacier has slowed by 10 %, due to the redirection of ice flow into its rapidly thinning neighbour. This process of “ice piracy” has not previously been directly observed on this rapid timescale and may influence future ice shelf and sheet mass changes. Read more
The system of atmosphere, land, ice and ocean in the region near the 79N Glacier in northeast Greenland: synthesis and key findings from the Greenland Ice Sheet–Ocean Interaction (GROCE) experiment The Cryosphere DOI 10.5194/tc-19-1789-2025 8 May 2025 The Greenland Ice Sheet represents the second-largest contributor to global sea-level rise. We quantify atmosphere, ice and ocean processes related to the mass balance of glaciers in northeast Greenland, focusing on Greenland’s largest floating ice tongue, the 79° N Glacier. We find that together, the different in situ and remote sensing observations and model simulations reveal a consistent picture of a coupled atmosphere–ice sheet–ocean system that has entered a phase of major change. Read more
Missing the input: the underrepresentation of plant physiology in global soil carbon research SOIL DOI 10.5194/soil-11-363-2025 5 May 2025 Plant physiology has been addressed by less than 10 % of peer-reviewed soil organic carbon research published in the last century. Thus, our understanding of soil carbon dynamics is overwhelmingly built on research that neglects the fundamental processes underlying organic carbon inputs. Active engagement of plant scientists in soil carbon research is imperative for shedding light on this blind spot and developing holistic policies that support soil carbon sequestration. Read more
Graphical representation of global water models Geoscientific Model Development DOI 10.5194/gmd-18-2409-2025 23 April 2025 Global water models contribute to the evaluation of important natural and societal issues but are – as all models – simplified representation of reality. So, there are many ways to calculate the water fluxes and storages. This paper presents a visualization of 16 global water models using a standardized visualization and the pathway towards this common understanding. Next to academic education purposes, we envisage that these diagrams will help researchers, model developers, and data users. Read more
High probability of triggering climate tipping points under current policies modestly amplified by Amazon dieback and permafrost thaw Earth System Dynamics DOI 10.5194/esd-16-565-2025 23 April 2025 We investigate the probabilities of triggering climate tipping points under various emission scenarios and how they are altered by additional carbon emissions from the tipping of the Amazon and permafrost. We find that there is a high risk for triggering climate tipping points under a scenario comparable to current policies. However, the additional warming and hence the additional risk of triggering other climate tipping points from the tipping of the Amazon and permafrost remain small. Read more
Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record Biogeosciences DOI 10.5194/bg-22-1929-2025 22 April 2025 We provide a new compilation of rates at which sediments deposited in the deep sea over the last 70 million years. We highlight a bias, linked to the drilling process, that makes it more likely for high rates to be recovered for younger sediments than for older ones. Correcting for this bias, the record shows, contrary to prior estimates, a more stable history, thus providing some insights on the past mismatch between physico-chemical model estimates and observations. Read more
The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system Biogeosciences DOI 10.5194/bg-22-1853-2025 15 April 2025 In acidic hot springs off Kueishantao, Campylobacteria fix CO2 by using the reductive tricarboxylic acid (rTCA) cycle, causing them to have an isotopically heavier biomass. Here, we report extremely low isotopic fractionation (of almost 0 ‰), which has never been reported in environmental samples. Moreover, the crab Xenograpsus testudinatus relies up to 34 % on campylobacterial biomass, highlighting the dependency of complex life on microscopic Bacteria in harsh environments. Read more
High-resolution Holocene record based on detailed tephrochronology from Torfdalsvatn, north Iceland, reveals natural and anthropogenic impacts on terrestrial and aquatic environments Climate of the Past DOI 10.5194/cp-21-795-2025 11 April 2025 Questions remain about the past climate in Iceland, including the relative impacts of natural and human factors on vegetation change and soil erosion. We present a sub-centennial-scale record of landscape and algal productivity from a lake in north Iceland. Along with a high-resolution tephra age constraint that covers the last ∼ 12 000 years, our record provides an environmental template for the region and novel insight into the sensitivity of the Icelandic ecosystem to natural and human impacts. Read more
Inter-model differences in 21st century glacier runoff for the world's major river basins The Cryosphere DOI 10.5194/tc-19-1491-2025 8 April 2025 Glacier models have historically been used to understand glacier melt’s contribution to sea level rise. The capacity to project seasonal glacier runoff is a relatively recent development for these models. In this study we provide the first model intercomparison of runoff projections for the glacier evolution models capable of simulating future runoff globally. We compare model projections from 2000 to 2100 for all major river basins larger than 3000 km2 with over 30 km2 of initial glacier cover. Read more
Stratospheric residence time and the lifetime of volcanic stratospheric aerosols Atmospheric Chemistry and Physics DOI 10.5194/acp-25-3821-2025 4 April 2025 The climate impact of volcanic eruptions depends in part on how long aerosols spend in the stratosphere. We develop a conceptual model for stratospheric aerosol lifetime in terms of production and decay timescales, as well as a lag between injection and decay. We find residence time depends strongly on injection height in the lower stratosphere. We show that the lifetime of stratospheric aerosol from the 1991 Pinatubo eruption is around 22 months, significantly longer than is commonly reported. Read more
Incorporating science communication and bicultural knowledge in teaching a blended volcanology course Geoscience Communication DOI 10.5194/gc-8-107-2025 3 April 2025 We added more science communication activities and cultural content from Māori cultural experts in a course that combines online interactive virtual fieldtrip content with reflective workshops, laboratory sessions, and fieldwork, to reflect a need for these skills in the Aotearoa NZ workforce. Students mentioned science communication and cultural competence more when responding to a survey question regarding What they learnt?, and they highlighted the importance that these skills might have for themselves. Read more
Pristine oceans are a significant source of uncertainty in quantifying global cloud condensation nuclei Atmospheric Chemistry and Physics DOI 10.5194/acp-25-3841-2025 2 April 2025 Aerosol particles in the atmosphere increase cloud reflectivity, thereby cooling the Earth. Accurate global measurements of these particles are crucial for estimating this cooling effect. This study compares and harmonizes two newly developed global aerosol datasets, offering insights for their future use and refinement. We identify pristine oceans as a significant source of uncertainty in the datasets and, therefore, in quantifying the role of aerosols in Earth's climate. Read more
Potential for equation discovery with AI in the climate sciences Earth System Dynamics DOI 10.5194/esd-16-475-2025 31 March 2025 AI is impacting science, providing key data insights, but most algorithms are statistical requiring cautious "out-of-sample" extrapolation. Yet climate research concerns predicting future climatic states. We consider a new method of AI-led equation discovery. Equations offer process interpretation and more robust predictions. We recommend this method for climate analysis, suggesting illustrative application to atmospheric convection, land–atmosphere CO2 flux, and global ocean circulation models. Read more
Composite model-based estimate of the ocean carbon sink from 1959 to 2022 Biogeosciences DOI 10.5194/bg-22-1631-2025 28 March 2025 The ocean is a major natural carbon sink. Despite its importance, estimates of the ocean carbon sink remain uncertain. Here, I present a hybrid model estimate of the ocean carbon sink from 1959 to 2022. By combining ocean models in hindcast mode and Earth system models, I keep the strength of each approach and remove the respective weaknesses. This composite model estimate is similar in magnitude to the best estimate of the Global Carbon Budget but 70 % less uncertain. Read more
Modulation of the northern polar vortex by the Hunga Tonga–Hunga Ha'apai eruption and the associated surface response Atmospheric Chemistry and Physics DOI 10.5194/acp-25-3623-2025 28 March 2025 In January 2022, the Hunga Tonga–Hunga Ha'apai (HTHH) volcano erupted, sending massive amounts of water vapour into the atmosphere. This event had a significant impact on stratospheric and lower-mesospheric chemical composition. Two years later, stratospheric conditions were disturbed during so-called sudden stratospheric warmings. Here we simulate a novel pathway by which this water-rich eruption may have contributed to conditions during these events and consequently impacted the surface climate. Read more
The glaciers of the Dolomites: the last 40 years of melting The Cryosphere DOI 10.5194/tc-19-1335-2025 26 March 2025 We have reconstructed the multi-decadal (1980s–2023) ice mass changes for all the current mountain glaciers in the Dolomites. We used historical aerial photographs, drone surveys, and lidar to fill the glaciological data gap for the region. We observed an alarming decline in both glacier area and volume, with some of the glaciers showing smaller losses due to local topography and debris cover feedback. We strongly recommend more specific monitoring of these glaciers. Read more
Decadal changes in phytoplankton functional composition in the Eastern English Channel: possible upcoming major effects of climate change Ocean Science DOI 10.5194/os-21-679-2025 24 March 2025 This study provides the first assessment of decadal changes in the whole phytoplankton community, addressed by flow cytometry, in the highly productive waters of the Strait of Dover. A significant surface seawater temperature increase of 1°C, associated with an important change in the nutrient concentration and balance, has triggered a change in the phytoplankton communities, characterized by a higher total abundance and an increasing proportion of the smallest cells (picroeukaryotes and picocyanobacteria). Read more
Reconstruction of Holocene and Last Interglacial vegetation dynamics and wildfire activity in southern Siberia Climate of the Past DOI 10.5194/cp-21-661-2025 21 March 2025 We analyse a southern Siberian stalagmite to reconstruct soil respiration, wildfire, and vegetation trends during the Last Interglacial (LIG) (124.1–118.8 ka) and the Holocene (10–0 ka). Wildfires were more prevalent during the LIG than the Holocene and were supported by fire-prone species, low soil respiration, and a greater difference between summer and winter temperature. We show that vegetation type and summer/winter temperature contrast are strong drivers of Siberian wildfires. Read more
Modelled surface climate response to effusive Icelandic volcanic eruptions: sensitivity to season and size Atmospheric Chemistry and Physics DOI 10.5194/acp-25-2989-2025 19 March 2025 We use an Earth system model to systematically investigate the climate response to high-latitude effusive volcanic eruptions as a function of eruption season and size, with a focus on the Arctic. We find that different seasons strongly modulate the climate response, with Arctic surface warming observed in winter and cooling in summer. Additionally, as eruptions increase in terms of sulfur dioxide emissions, the climate response becomes increasingly insensitive to variations in emission strength. Read more
Meteorological ingredients of heavy precipitation and subsequent lake-filling episodes in the northwestern Sahara Hydrology and Earth System Sciences DOI 10.5194/hess-29-1395-2025 17 March 2025 The Sahara was wetter in the past and may become wetter in the future. Lake remnants are evidence of the desert’s wetter past. If the Sahara gets wetter in the future, these lakes may serve as a water resource. However, it is unclear how these lakes get filled and how moisture is carried into the desert and converted into rain in the first place. Therefore, we examine processes currently leading to the filling of a dry lake in the Sahara, which can help assess future water availability. Read more
Assessing Lagrangian coherence in atmospheric blocking Nonlinear Processes in Geophysics DOI 10.5194/npg-32-51-2025 28 February 2025 We identify spatially coherent air streams into atmospheric blockings, which are important weather phenomena. By adapting mathematical methods to the atmosphere, we confirm previous findings. Our work shows that spatially coherent air streams featuring cloud formation correlate with strengthening of the blocking. The developed framework also allows for statements about the spatial behavior of the air parcels as a whole and indicates that blockings reduce the dispersion of the air parcels. Read more
Evaluating F10.7 and F30 radio fluxes as long-term solar proxies of energy deposition in the thermosphere Annales Geophysicae DOI 10.5194/angeo-43-175-2025 28 February 2025 We study how well the F10.7 and F30 solar radio fluxes have represented solar energy input in the thermosphere in the last 60 years. We found that increased saturation of radio fluxes at recent solar minima leads to an overestimation of solar energy, which changes the relation between thermospheric parameters and F10.7, but this is not an issue for F30 because of a relative increase in F30 with respect to F10.7. This explains why F30 has been found to represent solar energy better than F10.7. Read more
CH-RUN: a deep-learning-based spatially contiguous runoff reconstruction for Switzerland Hydrology and Earth System Sciences DOI 10.5194/hess-29-1061-2025 27 February 2025 This study reconstructs daily runoff in Switzerland (1962–2023) using a deep-learning model, providing a spatially contiguous dataset on a medium-sized catchment grid. The model outperforms traditional hydrological methods, revealing shifts in Swiss water resources, including more frequent dry years and declining summer runoff. The reconstruction is publicly available. RUN: a deep-learning-based spatially contiguous runoff reconstruction for Switzerland">Read more
Sensitivity of tropical orographic precipitation to wind speed with implications for future projections Weather and Climate Dynamics DOI 10.5194/wcd-6-231-2025 27 February 2025 Rainfall in mountainous regions constitutes an important source of freshwater in the tropics. Yet how it will change with global warming remains an open question. Here, we reveal a strong sensitivity of this rainfall to the speed of prevailing winds. This relationship, validated by theory, simulations, and observational data, suggests that regional wind shifts will significantly influence future rainfall changes in the tropics. Read more
Opinion: Why all emergent constraints are wrong but some are useful – a machine learning perspective Atmospheric Chemistry and Physics DOI 10.5194/acp-25-2365-2025 26 February 2025 In our article, we review uncertainties in global climate change projections and current methods using Earth observations as constraints, which is crucial for climate risk assessments and for informing society. We then discuss how machine learning can advance the field, discussing recent work that provides potentially stronger and more robust links between observed data and future climate projections. We further discuss the challenges of applying machine learning to climate science. Read more
Brief communication: Sea-level projections, adaptation planning, and actionable science The Cryosphere DOI 10.5194/tc-19-793-2025 25 February 2025 As communities try to adapt to climate change, they look for “actionable science” that can inform decision-making. There are risks in relying on novel results that are not yet accepted by the science community. We propose a practical criterion for determining which scientific claims are actionable. We show how premature acceptance of sea-level-rise predictions can lead to confusion and backtracking, and we suggest best practices for communication between scientists and adaptation planners. Read more
Synoptic perspective on the conversion and maintenance of local available potential energy in extratropical cyclones Weather and Climate Dynamics DOI 10.5194/wcd-6-211-2025 21 February 2025 Although extratropical cyclones in the North Atlantic are among the most impactful midlatitude weather systems, their intensification is not entirely understood. Here, we explore how individual cyclones convert available potential energy (APE) into kinetic energy and relate these conversions to the synoptic development of the cyclones. By combining potential vorticity thinking with a local APE framework, we offer a novel perspective on established concepts in dynamic meteorology. Read more
Toward more robust net primary production projections in the North Atlantic Ocean Biogeosciences DOI 10.5194/bg-22-841-2025 20 February 2025 The marine biogeochemistry components of Coupled Model Intercomparison Project phase 6 (CMIP6) models vary widely in their process representations. Using an innovative bioregionalization of the North Atlantic, we reveal that this model diversity largely drives the divergence in net primary production projections under a high-emission scenario. The identification of the most mechanistically realistic models allows for a substantial reduction in projection uncertainty. Read more
Creating a national urban flood dataset for China from news texts (2000–2022) at the county level Hydrology and Earth System Sciences DOI 10.5194/hess-29-767-2025 19 February 2025 We create China’s first open county-level urban flood dataset (2000–2022) using news media data with the help of deep learning. The dataset reflects both natural and societal influences and includes 7595 urban flood events across 2051 counties, covering 46 % of China’s land area. It reveals the predominance of summer floods, an upward trend since 2000, and a decline from southeast to northwest. Notably, some highly developed regions show a decrease, likely due to improved flood management. Read more
What controls planktic foraminiferal calcification? Biogeosciences DOI 10.5194/bg-22-791-2025 17 February 2025 Planktic foraminifers are a plankton whose fossilised shell weight is used to reconstruct past environmental conditions such as seawater CO2. However, there is debate about whether other environmental drivers impact shell weight. Here we use a global data compilation and statistics to analyse what controls their weight. We find that the response varies between species and ocean basin, making it important to use regional calibrations and consider which species should be used to reconstruct CO2. Read more
Moving beyond post hoc explainable artificial intelligence: a perspective paper on lessons learned from dynamical climate modeling Geoscientific Model Development DOI 10.5194/gmd-18-787-2025 14 February 2025 We draw from traditional climate modeling practices to make recommendations for machine-learning (ML)-driven climate science. Our intended audience is climate modelers who are relatively new to ML. We show how component-level understanding – obtained when scientists can link model behavior to parts within the overall model – should guide the development and evaluation of ML models. Better understanding yields a stronger basis for trust in the models. We highlight several examples to demonstrate. Read more
Causes of the exceptionally high number of fatalities in the Ahr valley, Germany, during the 2021 flood Natural Hazards and Earth System Sciences DOI 10.5194/nhess-25-581-2025 12 February 2025 In July 2021, flooding killed 190 people in Germany, 134 of them in the Ahr valley, making it the deadliest flood in recent German history. The flash flood was extreme in terms of water levels, flow velocities and flood extent, and early warning and evacuation were inadequate. Many died on the ground floor or in the street, with older and impaired individuals especially vulnerable. Clear warnings should urge people to seek safety rather than save belongings, and timely evacuations are essential. Read more
Turbulent heat flux dynamics along the Dotson and Getz ice-shelf fronts (Amundsen Sea, Antarctica) Ocean Science DOI 10.5194/os-21-359-2025 7 February 2025 Few observations exist in the Amundsen Sea. Consequently, studies rely on reanalysis (e.g., ERA5) to investigate how the atmosphere affects ocean variability (e.g., sea-ice formation and melt). We use data collected along ice shelves to show that cold, dry air blowing from Antarctica triggers large ocean heat loss, which is underestimated by ERA5. We then use an ocean model to show that this bias has an important impact on the ocean, with implications for sea-ice forecasts. Read more
Internal tides off the Amazon shelf in the western tropical Atlantic: analysis of SWOT Cal/Val mission data Ocean Science DOI 10.5194/os-21-325-2025 4 February 2025 This study focuses on the internal tides (ITs) off the Amazon shelf in the tropical Atlantic. It is based on 2 km horizontally gridded observations along the swaths of SWOT (Surface Water and Ocean Topography) track 20 during the calibration/validation phase (Cal/Val, 1 d orbit) from late March to early July 2023. We evaluate the amplitude of M2, N2, and S2 frequencies and use the M2 atlas as an internal tide correction model for SWOT observations. Internal tide amplitudes (models or atlases) are first derived by harmonic analysis of the SWOT sea level anomaly (SLA). The estimation is improved by performing a principal component analysis before the harmonic analysis. The results compare very well with the high-resolution empirical tide (HRET) internal tide model, the reference product for internal tide corrections in altimetry observations. The coherent mode 1 and mode 2 M2 can be distinguished in the internal tide model derived from SWOT, while the higher modes with their strong SLA signature are seen mostly in the incoherent part. In comparison to HRET, the correction of SWOT observations with SWOT-based atlases may be more relevant for this track. SWOT Cal/Val mission data">Read more