bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of dissolved-form 137Cs runoff from forest source watersheds 
Authors: Nagata Yutaro , Onda Yuichi , Takahashi Junko , Sakakibara Koichi
Published: March 2024

The concentration of dissolved-form 137Cs in forested rivers is known to increase during rainstorms, and direct leaching from litter and soil water is considered to be a factor. There have also been many studies showing that competing ions such as K+ and NH4+ promote the elution of 137Cs. However, there are no examples of detailed measurements of 137Cs concentrations and water quality characteristics of stream water and water passing through litter during actual rainstorms. In this study, stream water, throughfall,  water passing through litter, and groundwater were sampled in a small watershed in Fukushima Prefecture, Japan, which was affected by the Fukushima Daiichi Nuclear Power Plant, to measure dissolved 137Cs and dissolved organic carbon (DOC), K+and NH4+. NH4+ was not detected in stream water. The average concentrations of dissolved137Cs, DOC and K+ were 6.36 (mBq/L), 0.51 (mg/L) and 0.14 (mg/L), respectively, while the concentrations of 137Cs and DOC doubled to 13.38 (mBq/L), 1.13 (mg/L) during rainfall event and the K+concentrations remained unchanged (0.15mg/L). The concentrations of 137Cs and DOC  in the water passing through the litter were 50 and 30 times higher than in the stream water, respectively, suggesting that the high concentrations of dissolved 137Cs at the time of runoff were formed by leaching from the litter rather than by the presence of competing ions. The amount of 137Cs and K+eluted from the litter increased in the order of near-channel, saturated zone at run-off and slope, while the amount of DOC eluted from the litter was lower near the channel. These results suggest that 137Cs, K+and DOC release from near-channel litter is lower than that from litter on the slope because of the progress of leaching due to the occurrence of saturated surface flow.
Greenhouse gases gradients from Southern Greenland Fjords to subpolar North Atlantic Ocean
Authors: Leseurre Coraline , Delille Bruno , Roobaert Alizée , Boone Wieter , Crabeck Odile , Ponsoni Leandro , Theetaert Hannelore , T'Jampens Michiel , Verbrugge Silke , Gkritzalis Thanos
Published: March 2024

Since the beginning of the industrial era, the atmospheric greenhouse gases (GHG) have increased continuously (around +50% for carbon dioxide (CO2) and +150% for methane (CH4), for the two most important), causing the current climate change. In November 2023, the World Meteorological Organization (WMO) highlighted once again there are still significant uncertainties about the carbon cycle, its fluxes, and they stressed the importance to follow the non-CO2 GHG with greater global warming potential.The ocean, as a sink of anthropogenic CO2, plays a crucial role in climate regulation, whereas the surface seawater is naturally supersaturated in CH4, and shallow coastal waters are a source of CH4 to the atmosphere. However, the air-sea CO2 and CH4 fluxes are driven by different key processes depending on the region of the open or coastal ocean.To improve the understanding of the processes driving the air-sea exchange of GHG, we investigate the CO2 and CH4 concentrations and fluxes in open ocean and coastal areas affected by sea ice, glacier runoff and riverine inputs within the context of the European project GreenFeedBack. To do so, we measured CO2 and CH4 concentrations and calculated the fluxes, in surface water during a summer cruise (July-August 2023) conducted on board the RV Belgica in the subpolar North Atlantic Ocean, between Iceland and Southern Greenland Fjords. The data were obtained using a custom-made air-water equilibration system, that was connected to the vessel’s non-toxic seawater supply (equilibrator and Cavity Ring Down Spectrometer) and discrete sampling.Our first results show a pronounced gradient of CO2 and CH4 concentration between open ocean and the fjords. The oceanic CO2 concentration is minimal in the fjords where the CH4 concentration is maximal, indicating a potential impact of freshwater discharge on the GHG exchanges.
Regional modelling of water storage variations from combined GRACE/-FO and GNSS data in a Kalman filter framework
Authors: Wöhnke Viviana , Eicker Annette , Weigelt Matthias , Reich Marvin , Güntner Andreas
Published: March 2024

Water mass changes at and below the surface of the Earth cause changes in the Earth’s gravity field which can be observed by at least three geodetic observation techniques: ground-based point measurements using terrestrial gravimeters, space-borne gravimetric satellite missions (GRACE and GRACE-FO) and geometrical deformations of the Earth’s crust observed by GNSS. Combining these techniques promises the opportunity to compute the most accurate (regional) water mass change time series with the highest possible spatial and temporal resolution, which is the goal of a joint project with the interdisciplinary DFG Collaborative Research Centre (SFB 1464) "TerraQ – Relativistic and Quantum-based Geodesy".A method well suited for data combination of time-variable quantities is the Kalman filter algorithm, which sequentially updates water storage changes by combining a prediction step with observations from the next time step. As opposed to the standard way of describing gravity field variations by global spherical harmonics, we introduce space-localizing radial basis functions as a more suitable parameterisation of high-resolution regional water storage change. An estimation environment has been set up for the combination of GRACE/-FO satellite gravimetry with GNSS station displacements. The feasibility and stability of the approach is first demonstrated in a closed-loop simulation to test the setup and tune the algorithm. Subsequently, it is applied to real GRACE and GNSS observations to sequentially update the parameters of a regional gravity field model for Central Europe. The implementation was designed to flexibly include further observation techniques (e.g. terrestrial gravimetry) at a later stage. This presentation will outline the Kalman filter framework and regional parameterisation approach, and addresses challenges such as the relative weighting between the GRACE and GNSS data, and the appropriate choice of the Kalman filter process model and radial basis function parameterisation.
Strain partitioning and fault kinematics in the Northern Qilian Shan (NE Tibet) determined from Bayesian inference of geodetic data 
Authors: Zhang Yingfeng , Wimpenny Sam , Dal Zilio Luca , Shan Xinjian
Published: March 2024

Strain partitioning between strike-slip faults within mountain ranges and thrust faults along their margins is a common process that accommodates oblique plate convergence in continental collision zones. In these settings accumulated strain is periodically released by earthquakes on the strain-partitioned fault systems, which threatens the densely populated foreland areas. An extreme earthquake rupture scenario in these settings is that multiple faults rupture simultaneously releasing the built up strain – an example being the 2016 Mw 7.8 Kaikoura earthquake where a cascading rupture occurred on many separate faults with different kinematics. Recent work suggests that such cascading ruptures may occur in fault systems that are coupled in the shallow crust that are being loaded by a deeper, creeping fault. This study focuses on understanding earthquake risks in the northern Qilian strain-partitioned fault system, which is important due to the populated areas nearby. We investigate its 2-D kinematic models using available geodetic measurements under a Bayesian inversion frame. Our results prove that the kinematic models of the northern Qilian strain-partitioned fault system can be well determined, and compatible of the geological measurement and seismicity distribution. In contrast to the frequent thrust earthquakes, any thrust faults are not required to explain the available geodetic data indicating that the short-term geodetic measurements cannot reflect the thrust fault kinematics of the northern Qilian Shan in the geological time-scale. The non-thrust fault involved model also present a highly locked wedge beneath the foreland area, reconciling the supposed historical cascading earthquake ruptures in north Qilian Shan.
Climate-driven topographic asymmetry enhanced by glaciers: Implication for divide stability in glacial landscapes
Authors: Lai Jingtao , Huppert Kimberly
Published: March 2024

Climate contrasts across drainage divides, such as orographic precipitation, are ubiquitous in mountain ranges, and as a result, mountain topography is often asymmetric. Asymmetric glaciation arising from climate gradients across divides can cause topographic asymmetry that is potentially different from fluvial landscapes, causing divide instability during glacial-interglacial cycles. In this study, we quantified topographic asymmetry caused by asymmetric glaciation and assessed its sensitivity to different climate scenarios. Using an analytical model of a steady-state glacial profile, we find that the degree of topographic asymmetry is primarily controlled by differences in the Equilibrium Line Altitude (ELA) across the divide. When the ELA differences are caused by precipitation variations across the divide, glacial topography exhibits greater asymmetry than fluvial topography. These results suggest that glacial erosion responds differently to the same climate asymmetry from fluvial erosion, and therefore, intermittent glaciations may have promoted drainage reorganization and landscape transience in glaciated mountain ranges. Preliminary model results indicate that the rate of divide migration caused by asymmetric glaciation is several millimeters per year and the timescale of migration is several million years.
Archeo- and paleomagnetic records from Saint Helena, South Atlantic
Authors: Arneitz Patrick , Schnepp Elisabeth , Leonhardt Roman
Published: March 2024

The South Atlantic Anomaly (SAA) is a dynamic feature of the geomagnetic field. Systematic observations have revealed an expansion of the SAA in terms of its geographical extent and a decrease in field strength over the last decades. Its evolution can be reconstructed further back in time by means of archeo- and paleomagnetic investigations conducted on suitable recorders of the ancient geomagnetic field. Historical geomagnetic field models indicate a westward movement of the SAA from Africa during the last centuries, while its emergence is still under debate, mainly due to the lack of ancient field records in the Southern hemisphere. However, even on much longer timescales, paleomagnetic studies on volcanic rocks from the South Atlantic have suggested a persistence or recurrence of the anomaly.Here we present ancient geomagnetic field records from the island of Saint Helena from two different periods. Archeomagnetic directions and intensity were obtained from a historical lime kiln that operated until the middle of the 19th century. The reconstructed geomagnetic field components agree well with available instrumental measurements from the island. Geological timescales are covered by paleomagnetic examinations of lava flow profiles from Prosperous Bay and Munden’s Hill. A geomagnetic polarity transition was recorded by some flows at Properous Bay. Several other flows characterized by stable field directions are associated with weak intensities below 20 µT. These results suggest a prolonged anomalous field behavior in the South Atlantic region as indicated by previous studies.
The see-saw relationship of air pollution with climate: novel challenges to urban ecosystems
Authors: Mallik Chinmay
Published: March 2024

The significant transformations from rural to urban living encompasses substantial challenges related to climate action and sustainable development. Gaseous pollutants that were traditionally associated with rural livelihood are now also a challenge to urban ecosystems with CO being a prime example. Despite an overall decline in CO across the globe, the rate of decrease has actually slowed down in several regions of the world raising concerns of a global reversal. The trends in CO are found to be heterogeneous over urban regions of the world and concentrations do not always tally with emission inventories. Further, it is not only the trends that are changing over decades but also the global hotshots of several air pollutants, SO2 being a key example with the high values in Eastern China during the 2000s to enhanced values in Eastern India during the 2010s. Interestingly, when it comes to SO2, driven by the burning of coal, the hotspots in India are not in the Indo-Gangetic Plains (IGP) unlike CO or NH3, which are though driven by different sources e.g. combustion technologies and agricultural activities, respectively. Further, pollutants that were associated with indoor air studies with ramifications to human health are now increasing significantly at several locations in outdoor air, HCHO being a prime example. While the concentration of CO in India occurs in the IGP, unexpectedly enhanced formaldehyde levels were seen in certain pockets of India, away from the IGP, with trends that are higher than reported HCHO values across several parts of the globe. Apart from primary sources, HCHO is also an oxidation product of atmospheric volatile organic compounds (VOCs) and the high trend in HCHO observed during the summer months, generates interest on possible implications of atmospheric chemistry on ozone formation regimes in urban ecosystems. The changing temporal and spatial patterns necessitate mitigation strategies that do not completely depend on emission control and reduction but use alternate strategies like nature based solutions (NBS), particularly for urban ecosystems that harbor a larger population.
Evolution from Agulhas Ring to Mode-Water Eddy?
Authors: Oelerich Ria , Walter Maren , Bachmayer Ralf , Mertens Christian , Merckelbach Lucas , Carpenter Jeff
Published: March 2024

Agulhas Rings are anti-cyclonic warm-core eddies that originate from the interaction of the Agulhas current with the Antarctic Circumpolar Current (Agulhas Retroflection) at the southern tip of Africa. The Agulhas Rings are advected with the Benguela Current to the northwest and transport heat and salt into the South Atlantic Ocean and are thus affecting the ecosystem and the carbon cycle. The Walvis Ridge, which is located off the coast of Namibia, is a natural obstacle for the Agulhas Rings that are oftentimes unable to cross the ridge and thus remain in its vicinity until they dissolve. Due to the lack of long-term, high-resolution and sub-surface observations it is not well understood how the properties of these eddies evolve with time. We present long- and short-term observations from moorings (2022-2023) and two ocean glider campaigns (2022, 2023) as part of the SONETT I and SONETT II research expeditions near Walvis Bay. For the glider missions, automated adaptive sampling algorithms were developed to systematically improve the spatial and temporal resolution in the region of interest that is dynamically changing. Moreover, the gliders were equipped with microstructure probes for detailed energy dissipation measurements. In this study, we show how the eddy characteristics, such as temperature, salinity and oxygen, near Walvis Bay evolve with time and how these changes relate to the energy dissipation. Specifically in 2023, a deep glider (up to 1000 m) observed a unique eddy structure below the surface mixed layer that displayed subsurface eddy characteristics, but with a surface signal, indicating the characteristics of a mode-water eddy with a very distinct pattern of energy dissipation.
Simulating dissolved oxygen in the oceans – perspectives for the Baltic Sea
Authors: Löptien Ulrike , Dietze Heiner , Schneider Birgit , Renz Matthias , Karez Rolf
Published: March 2024

An increasing number of dead zones characterised by toxically-low levels of dissolved oxygen has been reported in coastal oceans all over the globe. Efforts towards respective quantitative descriptions are ongoing but numerical simulations and predictions of hypoxia remain challenging. In this study, we present a suite of generic approaches towards more reliable simulations.Along a test-case we showcase the coalescence of a suite of ultra-high (~ 100m horizontal) resolution general ocean circulation model of Eckernförde Bight (Baltic Sea) with machine learning approaches. The ocean model includes an elementary representation of the biogeochemical dynamics of dissolved oxygen. In addition, we integrate artificial “clocks” that measure the residence time of the water in Eckernförde Bight and the timescales of (surface) ventilation. Our approach starts with an ensemble of hindcast model simulations (covering the period from 2000 to 2018) designed to envelop a range of poorly known model parameters for vertical background mixing (diffusivity) and local oxygen consumption within Eckernförde Bight. In a subsequent step, feed-forward artificial neural networks trained with output from the model ensemble are put to work to identify predictors of hypoxia deep in Eckernförde Bight based on data at a monitoring site at the entrance of the bight. Our approach disentangles the relative importance of subduction and vertical mixing versus local oxygen consumption and the inflow of low-oxygenated waters from the Kiel Bight.
A new bachelor curriculum in Earth Sciences at Utrecht University, the Netherlands, in response to the needs of society
Authors: de Bresser Hans , Kleinhans Maarten , Mason Paul
Published: March 2024

Over the last 10 years, many universities worldwide have seen a decrease in enrolment in Earth Sciences bachelor’s and master’s degree programmes. Possible reasons for this decrease include the current image that secondary school students have of the Earth Sciences. Many of them consider the Earth Sciences as an old fashioned science, environmentally damaging and with insufficient emphasis on addressing societal problems. At Utrecht University, the Netherlands, the enrolment in the BSc Earth Sciences peaked in 2014 with an intake of 185, but has decreased since, in an irregular way, to 125 in 2022. For the current academic year, there has been a slight revival. A recent survey among 93 secondary school students confirmed that the Earth Sciences have an image problem, but also revealed low awareness of what the subject involves and what opportunities are available for graduates. Efforts are needed to change this. However, it is not a matter of simply improving publicity. We concluded that a modernization of our programme was also necessary, in order to reflect scientific advances of the last decades and the change in focus towards societal challenges, and to better prepare students for a professional career. As a result, we have constructed a fully integrated first year, including modular fieldwork covering topics across the full breadth of the Earth Sciences. After the first year, students choose one out of four ‘directions’. Each direction starts with its own set of foundation courses, followed by direction-related specialization electives. Seven skills learning lines are being implemented across the programme, providing the students with skills considered crucial for future Earth Sciences professionals. The students who started in September 2023 form the first cohort following the renewed BSc programme. Here we present the outline of the new programme and our first experiences. We address the issue of how to use our renewal in improving the image that secondary school students have of the Earth Sciences, expecting a positive effect on enrolment. More well-trained Earth Scientists are essential, not only to advance our science, but also to address the challenges society is faced with. 
Micro XRF elemental mapping for paleoclimate reconstruction in the Indian Ocean -to find exact timings of climate change-
Authors: Seki Arisa , Auer Gerald , De Vleeschouwer David
Published: March 2024

Non-destructive, high-resolution measurement of sediment cores are useful to reveal sediment feature which reflect climatic or oceanographic changes. Such non-destructive measurement (e.g. XRF core scanner measurement) could be reveal sediment feature in finer scale than discrete sample measurement. Although elemental mapping is also useful to reveal 2-dimentional structure of half split core surface, elemental mapping of large materials such as archive half core sections were usually difficult.In this study, we utilize recently released micro-XRF (M6 JETSTREAM provided by Bruker Corporation) which could measure archive half core directly and could make high-resolution element maps. The fine scale sediment feature which reflecting exact timings of drastic climate changes were revealed by micro-XRF using sediments obtained by following two Sites.Using the Neogene sediments obtained from DSDP Site 266, located at the high-latitude of Indian ocean close to the Antarctica, the distinctive chemical markers of IRD were observed in specific sections of Site 266. IRD is primarily distinguished by its characteristic iron-rich signature, and the identified fragments measure between 4.2 and 6.4 millimeters in length along their longest axis. Traditionally, these individual particles could only be discerned through destructive analysis. The large-scale micro-XRF capabilities of the JETSTREAM now enable us to non-destructively quantify and fingerprint IRD. The drastic changes of primary producer from the calcareous plankton to the siliceous plankton was also suggested from elemental mapping results.The sediments obtained from ODP Site 752, located on an isolated ridge in the Indian Ocean contained concretion at Paleogene age when hiatus or lower sedimentation rate was suggested by age model. We measured the concretion and the surrounding sediments together using specialized method of JETSTREAM, and revealed high-resolution elemental maps of concretion and surroundings sediments. The maps clearly shows that each element (Ca, Fe, Mn) is concentrated on different part on and around the concretion. The Ca concentration is higher at an interval above a concretion, which may suggest high calcareous productivity during the sedimentation period.In this study, we used legacy cores (archive halves) stored at Kochi Core Center (KCC), as the member of ReCoRD program (ReC23-01). Our measurement clearly shows reanalysis of previously obtained core materials by new technics reveals new feature of sediments which is useful to reconstruct past climate changes.
Linear snow dune orientations in Antarctica
Authors: Poizat Marine , Picard Ghislain , Arnaud Laurent , Narteau Clément , Amory Charles , Brun Fanny
Published: March 2024

Antarctica stands out as one of the windiest regions on Earth, resulting in snow transport and various eolian bedforms akin to those observed in subtropical sand deserts. Unlike sand dunes, Antarctic have been only qualitatively described, and little is known about their spatial distribution, orientation and dynamics. Therefore, fundamental questions about the processes of deposition and accumulation of snow remain unanswered, impacting the understanding of snow redistribution, surface mass balance variability in Antarctica and, more generally, the eolian transport of a cohesive material. In this study, we present a continent-wide mapping of linear snow dune orientations in Antarctica. We used Sentinel-2 and Landsat-8 images with, respectively, a 10 m and 15 m resolution to retrieve the orientation of periodic topographic features. Using wind direction and speed from ERA-5 Reanalysis with a 0.25°x0.25° resolution, we show that, on length scales ranging from 30m to several kilometers, longitudinal dune is the predominant type of landform in Antarctica and that they form by elongation in the mean snow flux direction. The predominance of the elongating mode indicates a low availability of mobile snow particles. This limited availability prevails at the continental scale due to a subtle balance between snow sintering, which limits erosion, and strong winds which rapidly removes snowfall. Our findings highlight the importance of snow sintering, not only to shape unique landforms, but also to control the amount of snow exported by wind to the ocean, an uncertain term of the ice-sheet mass balance.
Imaging the magma plumbing system of Ciomadul volcano and the Perşani Volcanic Field and constraining postcollisional magma dynamics 
Authors: Comeau Matthew J. , Hill Graham J. , Kovacikova Svetlana , Kamm Jochen , Lukács Réka , Seghedi Ioan , Grayver Alexander , Bondár István , Szabolcs Harangi
Published: March 2024

There are indications that some long-dormant or seemingly inactive volcanoes may have potentially active magma storage systems. One such system is Ciomadul volcano, which is located at the south-eastern terminus of the Carpathian volcanic chain (Romania). With the last eruption occurring at ~30 ka, this is the youngest volcano in eastern-central Europe. Understanding the nature and structure of the magma plumbing system is crucial to elucidating the evolution of the volcano and to assessing its hazard potential. This includes the depth, size, and geometry of the magma storage region, the amount and composition of the melt present, and the link between mantle and crustal processes.  Ciomadul is situated in a geodynamically active region about 50 km from the Vrancea zone, where deep earthquakes are frequent. These earthquakes may represent the descent of a dense lithospheric slab beneath a continental collision zone and this may imply an asthenospheric upwelling due to return flow of mantle material. To the north-west of Ciomadul lies a chain of older volcanic complexes, the Călimani–Gurghiu-Harghita volcanic complex; about 40 km west of Ciomadul towards the Transylvanian Basin, a monogenetic basaltic volcanic region was developed at 1.2–0.5 Ma (Perşani volcanic field). Seismic tomography has revealed low-velocity columns through the lithosphere beneath both Ciomadul and Perşani. However, high-resolution images of the complex geometry of the system are lacking.  We report here on a 3-D electrical resistivity model of the region that was generated from 41 magnetotelluric measurements acquired in 2022 that form a 75 km by 75 km array. The data typically had reliable periods from 128 Hz to 4,100+ s. Choosing appropriate locations for measurement was critical, away from sources of cultural electromagnetic noise that can contaminate the signals, as was careful data processing, including applying data pre-selection schemes and manual time windows in addition to standard approaches using robust statistics.  Phase tensor analysis suggests that the data are 3-D at all scales. The 3-D electrical resistivity model reveals conductive anomalies (
Distributions of river bank erosion in cold-climate regions identified using novel real-time sensors
Authors: van Rooijen Erik , Lotsari Eliisa
Published: March 2024

River functions and morphology are strongly impacted by the amount of sediments in a river, which are often supplied by river bank erosion. To better understand rivers as a whole it is thus important to know the timing and causes of river bank erosion, which are difficult to assess with current sensor technology. Especially in cold-climate regions where a large variety of processes occur that contribute to river bank erosion, identifying the timing and causes of bank erosion is challenging. We employed sensors, originally developed for the agricultural sector, in a novel way to obtain a one-year dataset of soil moisture, soil temperature and soil movement in real-time and with a high temporal resolution on three banks of northern rivers with different geographical, climatological and landscape characteristics. Thus, this research used a new type of dataset of soil temperature, moisture and movement never used before. We compared the timing of soil movement events with the soil temperature, soil moisture, air temperature and with discharge information. Specifically, the distribution of the soil movement events in time at each field site was analyzed. Furthermore, the distribution of time-lag between changes in these variables and a soil movement event were considered. The analysis of the results showed that there is no clear temporal distribution of bank movement in the Southernmost investigated site, while in the more Northern field sites soil movement was most frequent around the freezing and thawing periods (e.g. spring and autumn). At the northernmost field site an additional period with an increased frequency of soil movement events is likely caused by reindeer during summer months. The time-lag analysis also shows that freeze-thaw is likely the main driver of soil movement events in the investigated sites. The novel sensors allowed us to obtain a unique dataset which we used to identify individual soil movement events and helps to better understand river bank erosion and by extension fluvial systems in cold-climates.
Amplified Interannual Variation of the Summer Sea Ice in the Weddell Sea, Antarctic After the Late 1990s
Authors: Guo Yuanyuan , Chen Xiaodan , Huang Sihua , Wen Zhiping
Published: March 2024

The sea-ice extent (SIE) in the Weddell Sea plays a crucial role in the Antarctic climate system. Many studies have examined its long-term trend, however whether its year-to-year variation has changed remains unclear. We found an amplified year-to-year variance of the Weddell Sea SIE in austral summer since 1998/1999 in observational datasets. Analyses of sea-ice concentration budget and surface fluxes indicate that it is the thermodynamic process that drives the amplification of SIE variations, rather than the sea-ice-drift- related dynamic process. Compared to 1979–1998, the Southern Annular Mode in the preceding spring shows a closer linkage with the Weddell Sea SIE in 1999–2021 through a stronger and more prolonged impact on sea surface temperature, which thermodynamically modulates local sea ice via changing surface heat and radiation fluxes. Our study helps advance the understanding of extreme low Antarctic-SIE records occurring in recent decades and improve future projections of the Antarctic sea-ice variability.
Increasing root-derived soil carbon input to agricultural soils by variety selection of winter wheat
Authors: Heinemann Henrike , Seidel Felix , Don Axel , Hirte Juliane
Published: March 2024

Climate change mitigation and adaptation is a major challenge of modern agriculture. Increasing the incorporation of atmospheric carbon (C) as organic matter into soils through improved crop management seems to be a promising agricultural management option for supporting climate change mitigation. In order to build up soil organic C increased organic C inputs to the soil are urgently needed. In agricultural soils, crop roots are the major source of C inputs and pivotal for long-term C storage compared to aboveground biomass as their turnover is 2 to 3 times slower. This suggests, that variety selection towards increased root biomass can enhance root C inputs to the soil and could therefore increase C stocks and potentially facilitate C sequestration in soils. To quantify whether biomass allocation is affected by variety x environment interaction, we assessed root biomass, root distribution to 1 m soil depth and root: shoot ratios in a set of 10 different varieties grown at 11 experimental sites, covering a large European climatic gradient from Spain to Norway.Preliminary results show a broad variety-specific variation in biomass production and its allocation between roots and shoots. Root biomass ranged from 1 to 3.5 Mg ha-1 in the best variety and could be increased by 20% by selecting the best variety compared to the average root biomass without compromising yield. Root to shoot ratios varied between 0.04 and 0.58 with a mean of 0.16. Increased root biomass due to deeper roots may stabilise yields under future climate change conditions where increased frequency of drought events during vegetation periods are expected and may therefore be a climate change adaptation measure that increases the crops resilience towards changing environmental conditions. Thus, improved variety selection can help to achieve both goals of modern agriculture: climate change mitigation and adaptation.
A new technical framework for probability analysis of hydrological wet and dry encounter in changing environment
Authors: Ruan Yuli , Bao Zhenxin , Wang Guoqing , Liu Cuishan , Wang Yan
Published: March 2024

The calculation of hydrological encounter probability is of great significance to formulating joint prevention schemes for flood and drought disasters. Under the combined influence of global climate change and human activities, the consistency of hydrological processes has been destroyed, and the frequency and intensity of hydrological wet and dry encounters between river basins have become more complex, significantly impacting regional water resources security. Thus, this study provides a high precision hydrological wet and dry encounter probability analysis technology coupled with efficient dimensionality reduction theory:(1)The optimal distribution model of each marginal distribution is selected in the distribution model selector.(2)The cumulative distribution function(CDF1) and cumulative experience frequency calculated by the optimal distribution model are loaded into the regular feature learner to obtain the relationship function (RF) between the cumulative distribution function and the cumulative experience frequency.(3)The indexes reflecting the impact of climate change and human activities are loaded into the efficient dimensionality reduction tool to obtain the comprehensive and human activity indexes.(4)After considering the influence of the changing environment, the cumulative distribution function (CDF2) of the marginal distribution is analyzed using the GAMLSS model, and it is substituted into the RF to obtain the final cumulative distribution function (CDF_final). (5)Finally, the CVINECopula function and the encounter probability calculation method are used to calculate the probability of encountering wet and dry. This study fully considers the impact of climate change and human activities on hydrology and effectively avoids the problem of dimension disaster through an efficient dimension reducer. In addition, the coupled distribution model selector and the rule feature learner can significantly improve the calculation accuracy of the encounter probability of water resources.
The COST-G GRACE RL02
Authors: Jaeggi Adrian , Meyer Ulrich , Lasser Martin , Flechtner Frank , Dahle Christoph , Boergens Eva , Mayer-Gürr Torsten , Öhlinger Felix , Lemoine Jean-Michel , Bourgogne Stéphane , Döhne Thorben , Zhou Hao , Ran Jianjun , Chen Qiujie , Wang Changqing , Feng Wei
Published: March 2024

In 2019 the Combination Service for Time-variable Gravity fields (COST-G) started its operation with the first release of combined monthly GRACE gravity field models. Meanwhile almost five years have passed, while new experience was gained with the operational combination of the monthly gravity field models of the successor mission GRACE-FO, which has triggered a review of the weighting scheme and consequently a second release of GRACE-FO models in 2023. Moreover, the COST-G consortium has been in close cooperation with new GRACE/GRACE-FO analysis centers from China since spring 2020, which recently provided time-series of unconstrained models, covering the whole GRACE period, as it is requested by the COST-G processing standards. After careful evaluation of all individual time-series the whole GRACE time-series has now been recombined based on the new weighting scheme and also taking into account the contributions of the new COST-G analysis centers APM-SYSU, HUST, SUSTech and Tongji. We present the COST-G GRACE RL02 and also show latest results of the operational GRACE-FO combination.
Exploring the effects of sub-surface fault geometry on rupture propagation and long-term fault behavior
Authors: Zielke Olaf , Mai Paul Martin
Published: March 2024

Geometric complexity plays an important role for a fault’s seismotectonic behavior as it affects the initiation, propagation and termination of an earthquake and influences stress-slip relationships, fault-segment size, and the probability of multi-segment rupture. Consequently, geometric fault complexity is studied intensively and increasingly incorporated into computational earthquake rupture simulations. These efforts reveal a problem: While a natural fault’s geometry may be well quantifiable at the surface (i.e., the fault trace), its down-dip buried portion cannot be well constrained. At this point, it is not clear how this epistemic uncertainty affects the propagation of individual ruptures and a fault’s seismotectonic behavior (e.g., large-earthquake recurrence).We address this issue computationally with a physics-based multi-cycle earthquake rupture simulator (MCQsim), enabling us to investigate various aspects of rupture propagation and earthquake cycle in a controlled environment (e.g., with well constrained fault geometry). We approximate fault geometric complexity as a 2-D random field using the “random midpoint displacement” method which allows us to represent fault roughness (i.e., incorporate its epistemic uncertainty) while keeping the fault surface trace unchanged. Using MCQsim, we create 20kyr-long synthetic earthquake catalogs for strike-slip faults that share the same complex fault surface trace but have different sub-surface fault geometries. We analyze the resulting variations in single-event rupture propagation (i.e., the kinematic source model) and long-term seismotectonic behavior. We find that kinematic source models of individual events differ substantially between different realizations of sub-surface geometry. However, the long-term seismotectonic behavior (e.g., large-earthquake recurrence) does not differ as much and is less sensitive to the epistemic uncertainties of sub-surface fault geometry.
Influence of Enhanced Silicate Weathering on Streamwater Quality: A Watershed Experiment
Authors: Rioux Rob , Sun Fengchao , Tatge Wyatt , Zacharias Quinn C. , Miller-Brown William , Shanley James B. , Planavsky Noah , Raymond Peter A. , Saiers James
Published: March 2024

Enhanced Mineral Weathering (EMW), a Carbon Dioxide Removal approach, is of growing interest to scientists and practitioners due to its scalability, low technological demand, and co-benefits to farmers and soil health. Enhanced Silicate Weathering (ESW) is distinguished from EMW by grinding silicate rocks (e.g., basalt) into dust and applying it across a landscape, primarily agricultural land. After application, the silicate minerals react with carbonic acid (H2CO3) present in rainwater and soil pore water to generate weathering products such as base cations (Ca2+, Mg2+, Na+), alkalinity, trace elements (Al, Fe, Mn), and clays. These weathering products are used by plants or transported from the land to surface water. These weathering products influence streamwater chemistry by increasing in-stream pH, salinity, and alkalinity, which may worsen water quality and impair aquatic ecosystem function. Previous research has described the adverse water quality impacts of increased stream pH, salinity, and alkalinity at the continental scale across North America. The sources driving this change in freshwater quality have been identified as road salt, agricultural lime, and strong acids derived from anthropogenic activities (e.g., fertilizer and acid mine drainage). We are interested in understanding how ESW deployed at large scales may contribute to ongoing changes in freshwater quality. Here, in a small agricultural watershed in Northeastern Vermont, United States, we monitor water quality pre- and post-application of basalt at high-frequency intervals at two stream locations (measuring temperature, pH, specific conductance, dissolved oxygen, chlorophyll-a, and CDOM). In addition, we collected weekly baseflow water samples and stormwater samples across 19 rain events. All water samples were measured for a suite of chemical parameters, including DOC, alkalinity, major anions, cations, trace elements, and water isotopes. We analyze this data through multiple lenses, estimating changes to water quality, describing concentration-discharge dynamics, and analyzing aquatic ecosystem response via community respiration.
Mapping UK Drought Teleconnections from Ocean to Land
Authors: Chevuturi Amulya , Oltmanns Marilena , Tanguy Maliko , Harvey Ben , Svensson Cecilia , Hannaford Jamie
Published: March 2024

Given the anticipated changes in future UK drought occurrences attributable to climate change, there is an imminent requirement for a thorough understanding of the underlying influences behind UK drought events, particularly the most extreme events. In this context, our study aims to understand the North Atlantic oceanic drivers responsible for drought events in the UK, subsequently tracing the teleconnection pathways that connect these drivers to meteorological and hydrological droughts within the region. We examine the teleconnection pathways associated with drought conditions by assessing the concurrent and lagged statistical links between the UK's standardized precipitation index (SPI) and standardized streamflow index (SSI) and two distinct North Atlantic Sea surface temperature (SST) patterns, which are associated with freshening events. Our findings reveal that these North Atlantic SST patterns exert varying influences on two distinct regions of the UK (northwest and southeast), each of which have distinct hydrometeorological characteristics. The identified SST patterns are linked to the dominant modes of SST variability in the North Atlantic, thereby contributing to the predictability of drought occurrences across seasonal to multi-annual timescales, including at some very long lead times. Our research therefore has significant potential in practical applications for quantifying and managing drought risk, and for advancing drought forecasting and early warning systems through the identification of novel, skilful predictors. Ultimately, our work endeavours to contribute to the progress of sustainable water resource management amidst the escalating drought risks in the UK.
Early Initiation of Tasman Leakage and the formation of modern Indian Ocean circulation
Authors: Lyu Jing , Barragán Montilla Sofia , Bialik Or , Christensen Beth , Auer Gerald , Sarr Anta-Clarisse , De Vleeschouwer David
Published: March 2024

The exchange of water between the Pacific and Indian Oceans is important in regulating planetary climate. North of Australia, this exchange plays a key role in regulating the Indo-Pacific Warm Pool with far-reaching effects via Indonesian Throughflow (ITF). The exchange south of Australia is far less understood, and much of the exchange occurs at intermediate depths through Tasman Leakage (TL). Here, we investigate Ocean Drilling Program (ODP) Site 752 which was drilled on Broken Ridge. The Site is located within the path of TL, and thus, can provide a paleoceanographic history of TL. Benthic foraminiferal (BF) assemblage is a useful tool to reconstruct paleoceanographic patterns. At ODP Site 752, BF assemblages vary over time but at no point exhibit evidence of extreme stress or oxygen deficiency. Benthic foraminiferal diversity measured with the Fischer Alpha diversity index remains between 5 and 10, indicating moderate diversity throughout the last 9 million years. Furthermore, the high abundance of epiphytic species Cibicidoides wuellerstorfi and Lobatula lobatula likely reflects a high current energy environment over Broken Ridge during this time. Based on our comprehensive benthic foraminiferal assemblage study, we suggest that the driving factor behind the benthic ecological changes on Broken Ridge since the Late Miocene has been TL intensity, distinguished by its kinetic energy. In addition, we present a ~13 Myr neodymium (Nd) isotopic record, suggesting that TL onset likely occurred sometime in the late Middle Miocene, advecting isotopically older Pacific-sourced waters into the Indian Ocean. The latter findings challenge the previously presumed onset of TL at ~7 Ma and indicate a much earlier initiation of TL between 14 – 10 Ma, that intensified during the Late Miocene when the modern-like TL was established.
Adjusted models for aquifer thermal energy storage (ATES) systems simulations
Authors: Halaj Elzbieta , Papiernik Bartosz , Pajak Leszek
Published: March 2024

ATES systems can be coupled with various types of building facilities providing heating, cooling and thermal energy storage. The thermal performance and dynamical simulations of ATES systems should be provided based on local structural and parametric framework.A static model, which can correctly represent the geological nature of the reservoir, is necessary in order to achieve a reliable evaluation and assessment through numerical simulations.Recent 3D static geomodels from petroleum exploration built for R&D purposes of Department of Energy Resources AGH University of Krakow were adjusted for further geothermic and energy storage fields (ATES, CO2 sequestration) purposes.These parametric geomodels are very complex, handling large quantities of input data. A typical static modelling workflow comprises 6 main phases of modelling, starting from database building, through structural modelling, facies modelling, petrophysical modelling, up to volume and reserves calculations and risk assessment.  One of the examples is a performance simulation of ATES in the Lower Cretaceous reservoir in Central Poland, where a regional Petrel© static parametric model was prepared prior to dynamic simulations in Feflow© software. A methodology of fitting Petrel’s structural and parametrical model to Feflow requirements were prepared.The basic surfaces constraining the geometrical framework of the dynamic model — in particular top and base on the Lower Cretaceous — were extracted from the regional model. The square part of this model was extracted and subsequently converted into formats applicable in Feflow©. Further assumptions were made for geological and thermal parameters.In result, the ATES systems can be simulated as a doublet of multilayer wells, which applies a pre-defined extraction or injection nodes along a well screen. The dynamic model was divided in sub-layers of variable thickness. The porosity in the Lower Cretaceous formations was set according to geological staticmodel. The thermal model of the area was then validated and compared with the geological static model. The performance of ATES simulation was conducted for 30 years according to its specific demand profile. 
Thermosphere model assessment and implementation at NASA/CCMC
Authors: Bruinsma Sean , Laurens Sophie , Wang Jack , Yue Jia , Kuznetsova Maria
Published: March 2024

Appropriate metrics to track the progress over time of thermosphere models, both first principle and semi-empirical, were developed. Secondly, the high quality and high-spatial resolution neutral density data sets of TU Delft covering long intervals of time (i.e. the complete CHAMP, GRACE, GRACE-FO and GOCE mission datasets) were selected. The neutral density observations can then be used to verify model accuracy with respect to latitude-longitude-local time variations, and solar and geomagnetic activity levels and seasonal variations, respectively. The density data and metrics together allow benchmarking of the models, and improvement from one release to the next can be quantified. An assessment tool was implemented at CCMC specifically for storm-time assessment, while global assessment capacity is currently also under development.In this study, we present the results of comparisons with storms from 2001-2022 for the DTM2020, NRLMSISE-00 and JB2008 models. Secondly, the CCMC CAMEL model assessment tool will be shown and the model score cards that it can generate. These score cards allow easy and objective comparison of the performance of thermosphere models.