bluuebunny/crossref_metadata_2025 huggingface dataset:
Geoethics – an new approach to include awareness for sociocultural context 
Authors: Schneider Simon
Published: March 2022

If the geosciences demand to be taken more seriously and to play a greater role in political and societal decision-making, they must take on great responsibility.

If we are to act ethically, we must define values against which decisions about ethical behavior can be made. These values are often summarized as shared geoethical values (see Peppoloni & di Capua, 2017).

These values can be found on  

an Ethical dimension: for example, honesty, integrity, awareness, accuracy, collaboration, inclusiveness, civility, and fairness,

a Social dimension: addressing the grand challenges (sustainability, prevention, education),

a Cultural dimension: values such as geological diversity, diversity of geological-geographical landscapes or geological heritage.

Although these values are well founded and can be considered shared values, we need to be aware that they represent a strongly academic (Western) perspective and to some extent disregard other knowledge systems, such as indigenous or traditional ecological knowledge, as well as stressful socioeconomic contexts.

This creates fundamentally new challenges, for example, when the evaluation criteria of different sustainability goals are not compatible with local or regional socio-cultural values. Even different prioritizations can lead to difficulties here, which have an impact not only on research and development but even more so on recommendations for action resulting from the research. Examples of this can be found in the context of the current global Grand Challenges. The increasing demand for highly specialized raw materials, emerging conflicts over resources such as drinking water or soil, or the developments regarding coastal protection caused by climate change are some examples.

With this presentation we want to raise awareness of socio-cultural differences. In order to act geoethically, we need to consider the sociocultural context. Therefore, we want to initiate a discussion on whether and how a contextual model can be integrated into the concept of geoethics. This contextual model (in analogy with Neuliep's Contextual Model of Science Communication, 2021) seems to be able to solve the problems that arise when the geosciences claim the important role in global decision making mentioned above.
Variable Early Eocene continental hydroclimate in Central Europe? 
Authors: Schmitt Clemens , Vasiliev Iuliana , Martínez-García Alfredo , Mulch Andreas
Published: March 2022

Predicted future climate scenarios share similar characteristics with the Eocene ‘greenhouse’ period. However, short-term Early Eocene terrestrial climate variability is still poorly constrained mainly due to the rarity of adequately resolved climate archives. This lack of information restricts not only the evaluation of past continental climate conditions but additionally limits regional climate modelling efforts but also the validation of model outputs. Here, we present highly-resolved biomarker-based (bacterial membrane lipid and leaf wax) paleoclimate data from the UNESCO World Heritage Site Messel Fossil Pit (Germany) that cover an interval of ca. 640 ka. The drilled Messel paleolake succession, characterized by finely laminated and frequently varved black pelites (referred to as ‘oil shale’) represent a regional climate and environmental archive from the latest Early to Middle Eocene (~48.0-47.4 Ma) of western Central Europe. Downcore mean annual air temperature (MAAT) reconstructions inferred from bacterial-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs) show a long-term cooling trend and range from 14 to 22°C. High-resolution sampling within the basal and middle core interval reveal several short-term negative temperature excursions of 4-5°C, respectively. Moreover, we measured compound-specific δ2H and δ13C of excellently preserved odd carbon numbered mid- and long-chain leaf wax n-alkanes in order to estimate past regional hydroclimatic conditions. δ2H values of terrestrial long- and aquatic mid-chain n-alkanes show exceptional variations of up to 45‰ and 60‰, respectively. In contrast, δ13C values of long-chain n-alkanes are within 5‰ (-28‰ to -33‰) while mid-chain δ13C values vary by 11‰, ranging between -26‰ and -37‰. Our results indicate that the Early to Middle Eocene temperature history of central western Europe, particularly on short geological timescales was much more variable than previously assumed. We recognize two abrupt shifts in MAAT that coincide with lower δ2H values and therefore may point to either wetter climate conditions or changed atmospheric moisture trajectories. We emphasize that the long-term decline in estimated MAAT towards the top of the Messel section has to our best knowledge not been quantified from any time-equivalent terrestrial archive in Central Europe, but resembles Early Eocene cooling patterns well-documented from the global oceans.
Gravity and magnetic fields of Mars - new findings
Authors: Klokocnik Jaroslav , Kletetschka Gunther , Kostelecky Jan , Bezdek Ales , Karimi Kurosh
Published: March 2022

A search for water on Mars is an important part of a space program. Water is likely to be contained not only in the polar caps but also deposited further away from the polar regions, specifically in the so called “fretted terrain” (near dichotomy boundary between the lowlands and highlands), in the northern lowlands, and elsewhere.  Here we attempt to reconstruct a northern paleo-ocean, using the gravity aspects and locations of features of the fretted terrain as constraints for paleo-seashore. Valles Marineris would contain water that would flow into this ocean. We use recent data on the gravity and magnetic fields of Mars and create from them the gravity aspects and magnetic field proxies computed from the recent gravity and magnetic models JGMRO_120F (Konopliv et al., 2020) and (Connerney et al., 2005; Langlais et al., 2019). We discovered that Isidis, based on gravity aspects, has many volcano-like characteristics despite the traditional view of this structure being an impact related. We note asymmetric positions of Martian polar caps that seem to be related to the magnetic field distribution and we propose a new hypothesis that polar cap accumulation relates to a plasmasphere interaction with the solar wind.  Analysis of the detection of direction of the impactor arrival for Hellas impact basin along with the gravity aspects (namely the strike angles) suggested  that not only the impact likely generated a reset of the global plum activity (that changed the overall unicellular convection pattern into the bicellular convection) but also note the possibility that the magnetic maxima in the polar region could be paleoindicators of the offset by this impact event so that the rotational poles have an offset from the magnetic poles.

 
Mapping the distribution of strain along multiple strike-slip faults in the Chaman fault system from InSAR
Authors: Dalaison Manon , Jolivet Romain , Le Pourhiet Laetitia
Published: March 2022

The Chaman plate boundary between India and Eurasia is a wide faulted region in Pakistan and Afghanistan, hosting distributed seismicity. Along the western edge of the deforming region, the Chaman fault currently accommodates less than 15 mm/yr of slip, while the differential left-lateral motion between both tectonic plates is close to 30 mm/yr. In the past century, significant earthquakes have ruptured structures east of the Chaman fault, including the 1931 Mach earthquake and 1935 Quetta earthquake with magnitudes (Mw) greater than seven. We aim to identify where strain focuses so that active structures likely to rupture in large earthquakes are outlined. We use ground velocities computed from 6 years-long InSAR time series in ascending and descending line of sights to map gradients of deformation in the Kirthar ranges. InSAR data reveals that most of the current plate boundary strain focuses east of the Chaman and Ghazaband fault in the central axis of the ranges. We model velocities along profiles across the plate boundary as the surface expression of left-lateral slip on several vertical faults: the Chaman fault, the subparallel Ghazaband fault, the Hoshab fault and one to three unknown faults to the east. We localise strain in the continuation of the Ornach Nal in the south and along the Quetta-Kalat fault which is thought to have hosted the 1935 Quetta earthquake (Mw 7.7). Three discrete portions of the Ghazaband fault slip with rates close to 10 mm/yr. Our description of partitioning matches known seismic ruptures, and makes sense in a geodynamical and geological perspective. We propose a tectonic model of the plate boundary evolution with an eastward migration of strain.
Evaluation of a state-wide drainage monitoring in Mecklenburg-Vorpommern using artificial intelligence methods
Authors: Steidl Jörg , Lischeid Gunar , Engelke Clemens , Koch Franka
Published: March 2022

One challenge for modern agricultural management systems is to reduce their detrimental effects on water quality of water bodies. With this in mind, monitoring was carried out on behalf of the State Agency for Environment, Nature Conservation and Geology Mecklenburg-Vorpommern in the drainage outlets of 19 arable fields distributed throughout the state. In long-term measurement campaigns, runoff and substance concentration were determined at the drainage outlets. As expected with intensive arable land use, the nitrogen concentrations of most samples were far above the current quality standards and target values for surface waters according to the Surface Water Ordinance. Phosphorus concentrations were also generally very high. In parallel to the measurements, extensive data on agricultural management were collected and then correlated, together with pedological and meteorological data, with the temporal dynamics and spatial patterns of substance concentrations in drainage runoff. After selection and processing, 1037 data sets with 19 measured variables were available for the analyses.

These data were first subjected to a principal component analysis. The first seven principal components were each assigned to specific effects. The values of the principal components were interpreted as quantitative measures of the strength of the expression of these effects in the individual water samples. These were then placed in relation to extensive meteorological, hydrological, soil and management data. Classical correlation analyses revealed a bewildering variety of significant effects. Using random forest models, however, it was possible to map a large part of the observed spatial and temporal variance with just a few explanatory variables in each case.

The temporal dynamics of the nutrient concentrations in the outlet of the drains were mainly determined by hydrological conditions and weather. In contrast, direct short-term effects of individual arable farming measures on nutrient dynamics in the drainages could not be identified. Instead, clear indications of long-term effects of agriculture were found. In particular, the nitrogen and phosphorus balances of the areas played a decisive role. Soil recovery from long-term fertilisation thus does not seem to be achievable either through minor changes in agricultural management or in the short term.

Furthermore, it was shown that the many years of intensive use of the land had a massive impact not only on the nitrogen and phosphorus contents, but also on almost all other substances studied. Nitrogen and phosphorous data alone can only provide limited information on the source and development of soil eutrophication. This is still given too little attention in studies on the substance balance of agriculturally used land.
Water masses variability in the eastern Fram Strait explored through oceanographic mooring data and the CMEMS dataset
Authors: Dentico Carlotta , Bensi Manuel , Kovačević Vedrana , Zanchettin Davide , Rubino Angelo
Published: March 2022

The interaction between North Atlantic and Arctic Ocean waters plays a key role in climate variability and in
driving the global thermohaline circulation. In the past decades, an increased heat input to the Arctic has
occurred which is considered of high climatic relevance as, e.g., it contributes to enhancing sea ice melting.
In this frame, the progressive northward extension of the Atlantic signal within the Arctic domain known as
Arctic Atlantification is one of the most dramatic environmental local changes of the last decades.
In this study we used in situ data and the Copernicus Marine Environment Monitoring Service (CMEMS)
reanalysis dataset to explore spatial and temporal variability of water masses on different time-scales and
depths in the eastern Fram Strait. In that area, warm and salty Atlantic Water (AW) enters the Arctic Ocean
through the West Spitsbergen Current (WSC). Time series of potential temperature, salinity and potential
density obtained from CMEMS reanalysis in the surface, upper-intermediate and deep layers referring to the
period 1991-2019 have been considered. High-frequency observations gathered from an oceanographic
mooring maintained by the National Institute of Oceanography and Applied Geophysics (OGS) in
collaboration with the Italian National Research Council - Institute of Polar Science (CNR-ISP) have been
used to assess the reliability of CMEMS data in reproducing ocean dynamics in the deep layer (ca 900-1000
m depth) of the SW offshore Svalbard area. The mooring system has been collecting data since June 2014.
In this contribution, we will show how the CMEMS data compared with in situ measurements as far as
seasonal and interannual variations as well as long-term trends are concerned. We will also discuss how
CMEMS reanalyses show differences in resolving ocean dynamics at different depths. Particularly, the severe
limitations in reproducing thermohaline variability at depths greater than 700 m. Finally, we will illustrate how
our results highlight strengths and limitations of CMEMS reanalyses, underscoring the importance of
optimizing measurements in a strategic area for studying climate change impacts in the Arctic and sub-Arctic
regions.
250 years of daily weather: a reconstruction of temperature and precipitation in Switzerland since the late 18th century
Authors: Imfeld Noemi , Pfister Lucas , Brugnara Yuri , Brönnimann Stefan
Published: March 2022

Numerous historical sources report on hazardous past climate and weather events that had considerable impacts on society. Studying for example mechanisms of such events is however hampered by a lack of spatial weather information. Gridded high-resolution daily data sets mostly cover the past few decades. For Switzerland, Pfister et al. (2019) reconstructed daily fields of precipitation and temperature back to 1864, but the century before this year would be particularly relevant to study the transition from the Little Ice Age climate to the Anthropocene and to analyze the anomalous, volcanically-perturbed climate in the early 19th century and late 18th century. Here we present a daily high-resolution (1x1 km2) reconstruction of temperature and precipitation fields for Switzerland for the years 1763 to 1960 using the analog resampling method (ARM). Together with the present-day meteorological fields, this forms a 250-year data set. The ARM samples temperature and precipitation fields for the historical period from the most similar days in a reference period. These most similar days are selected based on the smallest distance calculated between the observational data in the historical period and the reference period. As observational data, we use temperature, pressure, precipitation, and precipitation occurrence. The resampled fields are then post-processed by assimilating historical temperature measurements and adjusting precipitation fields using isotonic distributional regression. Despite the much scarcer data availability in the period before 1864, evaluation results are promising for the temperature reconstruction with correlation values of on average 0.9 and root mean square errors of on average 1.8°C. For precipitation, the evaluation results are less promising with correlation values of on average 0.7 and root mean square errors of on average 5 mm. Due to its high spatial variability and the small number of records in the historical period, precipitation is more difficult to reconstruct. With the here presented data set, it is now possible to study historical weather and climate events in their spatial extent, such as the warm summer in 1807, and bring it into context leveraging other historical sources. The data set can further be used to calculate impact-relevant indices, for agricultural, phenological, and hydrological modeling.
On the Disaster Risk Reduction of Land Subsidence in Indonesia's Northern Coastal Areas of Java
Authors: Abidin Hasanuddin Z. , Andreas Heri , Gumilar Irwan , Sidiq Teguh P. , Pradipta Dhota , Yuwono Bambang D.
Published: March 2022

Land subsidence has been observed in several locations along Indonesia's northern coast of Java, most notably in Jakarta, Indramayu, Semarang, Demak, and Pekalongan. It could be caused by a combination of natural and anthropogenic processes, such as excessive groundwater extraction, natural consolidation of alluvium soil, building and construction load, and tectonic activity. Observations using various geodetic methods, including Leveling, GPS, and InSAR, show that typical subsidence rates of 3-10 cm/year have occurred and continue to occur at these locations. The rates vary both spatially and temporally. Coastal subsidence causes coastal inundation, flooding, and infrastructure sinking and cracking, resulting in significant infrastructure, economic, environmental, and social losses. Coastal flooding and inundation are typically exacerbated by high tides, high waves, and heavy rain. Given the significant impact of land subsidence in the coastal area on community life activities and regional development, sustainable disaster risk reduction management must be used to prevent and mitigate land subsidence. Furthermore, because this phenomenon persists, both the government and the community must continue to adapt to its consequences. This paper describes the observations and effects of land subsidence on Java's north coast, specifically in Jakarta and Semarang. Initiatives and programs to aid in prevention, mitigation, and adaptation will be proposed and discussed.
Modelling interannual variability in a tropical cyclone hazard model
Authors: Ermis Shirin , Toumi Ralf
Published: March 2022

Tropical cyclones (TCs) are some of the most dangerous natural hazards that human civilisation is exposed to. Effective adaptation for coastal regions requires reliable forecasts of risks for the season. Natural Hazard models such as the Synthetic Tropical cyclOne genRation Model (STORM) developed by Bloemendaal et al. (2020) are a common choice to assess risks without the expense of running a full forecast model. STORM has so far only been compared to observations on a basin-wide scale. However, for useful risk assessments in coastal regions, the model is also required to be skilful on much smaller spatial scales. We examine landfall statistics in some key areas such as the Gulf of Mexico.  Numerous indices for TC genesis have been developed over the past decades that aim to derive genesis locations from meteorological variables. None of the currently operational indices however is capable of realistically modelling interannual variability in genesis numbers and locations. Here, we compare the purely statistical Poisson interannual variability to that observed. Using Poisson regression between observations and driving environmental variables such as relative sea surface temperatures and wind shear, we then produce a new index for genesis location that has better predictive skill on interannual time scales.
Effects of Forbush Decreases on Clouds as determined from PATMOS-x
Authors: Matsumoto Haruka , Svensmark Henrik , Enghoff Martin
Published: March 2022

This study examines the relationship between cosmic rays and clouds during Forbush decreases (FDs) to understand the cause-effect relationships between cloud microphysics, cloud condensation nuclei (CCN), and ionisation in the atmosphere. The results of a Monte Carlo analysis of cloud parameters during FDs from newly calibrated satellite data, namely, the Pathfinder Atmospheres Extended (PATMOS-x) from 1978 to 2018, show the connections between some cloud parameters and FDs. For context, FD is the event where, the amount of cosmic rays arriving in the atmosphere decreases and recovers over several days. Other studies have shown that FDs impacted the cloud fraction, aerosol optical depth, CCN, water content, and cloud effective radius (reff ) in the atmosphere. Using the Monte Carlo analysis, nine atmospheric parameters from the dataset were evaluated for a significant response level to FDs. Each FD event added (after the first event) reduces the noise, but only the strongest events add a significant signal (exceptionally when the 2nd and 5th rank FD data are added, the signal/noise ration dropped due to change of satellite version). We found that cloud fraction shows statistically significant signals following FDs at an achieved significance level of 0.33%. Cloud emissivity also showed highly significant signals from the analysis, however these cannot be determined as physical cause by FDs since the response starts a week before the FDs. In contrast, the cloud optical depth, integrated total cloud water over the entire column, and reff did not show any significant signals in frameworks of the applied methods. The top-of-atmosphere brightness temperature at nominal wavelengths of 3.75, 11.0, and 12.0 µm and surface brightness temperature were analysed anew and showed significant signals. The estimated brightness temperature changes from a radiative transfer model (Fu-Liou model) show consistent results with the observed changes in cloud parameters during FD events. Among analysed several atmospheric/cloud/aerosol parameters, cloud fraction and the top-of-atmosphere brightness temperature at nominal wavelengths of 3.75, 11.0, 12.0 µm remain the only parameters depicting a statistically significant and correct-phase response to FDs.
Hydrological drivers of the spatial distribution of herbaceous wetland communities at Poyang Lake
Authors: Huang Wenqin , Hu Tengfei , Mao Jingqiao , Montzka Carsten , Bol Roland , Wan Songxian , Yue Jin
Published: March 2022

Hydrological processes are known as driving forces in structuring wetland plant communities, but still specific relationships are not always well understood. The dynamic, seasonally inundated wetland at Poyang Lake (less than 1000  km2 in the dry season and more than 3000 km2 in the wet season), the largest freshwater lake in China, underpinnes critical regional ecosystem services (e.g. flood water retention, water supply and biodiversity conservation). However, recent drier conditions of Poyang Lake are having a profound impact on its wetland vegetation leading to degradation of the entire wetland ecosystem, thereby also threatening the winter habitat of migratory birds. We aim to develop an integrated framework to quantitatively investigate the spatial distribution of major herbaceous communities that provide habitat for the migratory birds in response to Poyang Lake flood inundation. First, ground references are obtained from a combination of drone imagery and field surveys as an input for the wetland herbaceous community classification model. Our classification model is based on a machine learning technique applied to Sentinel-2 satellite data. This new search strategy provides an accurate classification based on the more optimal input variables and model parameters gained simultaneously. Secondly, based on the dynamic changes in water levels since 2000, we statistically evaluate the key environmental drivers of the hydrological regime on the spatial distribution of the wetland vegetation communities. This showed that: 1) different plant communities exhibited varying tolerance to flood inundation and 2) two key factors, i.e., average water depth and average duration of the inundation events, were found to be able to characterize the communities’ tolerance independently. For example, Carex cinerascens Ass. which had the widest inundation stress tolerance, being adapted to an inundation duration of 120~230 d and depth of 1.5~1.7 m, accounted for the largest herbaceous community (>27% cover) within the entire study area. Different survival strategies to inundation stress, such as dormancy and morphological restructuring, can explain the varying tolerance of plant species/communities. Our work elucidated the linkages between hydrological processes and herbaceous plants’ distribution in wetlands, and the approach can be readily applied at small to large catchment scales and provides a straightforward practical tool to predict the possible responses of the lake wetland vegetations to potential hydrological changes.
Wavelet cross-correlation dynamical network of the coherent GIC response to intense geomagnetic storms in the high voltage grid of Great Britain
Authors: Chapman Sandra , Orr Lauren , Beggan Ciaran
Published: March 2022

During geomagnetic storms rapid magnetic variations cause large, sharp enhancements of the magnetic and geoelectric field at mid-latitudes. These present a potential hazard to grounded technology such as high voltage transformers, pipelines and railway systems. Spatio-temporal quantification can provide insight into the magnitude and configuration of their potential hazard. We perform a wavelet decomposition on both European ground-based magnetometer measurements and modelled Geomagnetically Induced Currents (GICs) from the high voltage grid of Great Britain (GB).  A wavelet decomposition localizes the signal in the time-frequency domain, and we show that in both magnetometer observations, and modelled GIC response, the Haar wavelet extracts the signal power and waveform at the signal fastest rate-of-change.

We then use Haar wavelet cross-correlation of the GIC in the grounded nodes to build a time-varying network of GIC coherent response around the GB grid during intense geomagnetic storms [1]  including the 2003 Halloween storm. We find a highly intermittent (few 10s of minutes duration) long-range coherent response that can span the entire physical grid at most intense times. The spatial pattern of coherent response seen in the GIC flow network does not simply follow that of the amplitude of the rate of change of B field that is estimated via the Haar wavelet. Coherent response is excited across spatially extended clusters comprised of a subset of nodes that are highly connected to each other, with a tendency for east-west linkages following that of the physical grid, simultaneous with  the overhead presence of the auroral electrojet and the inducing component of the magnetic field. This can quantify the spatial and temporal location of increased hazard in specific regions during large storms by including effects of both the geophysical and engineering configuration of the high voltage grid.

[1] L. Orr, S. C. Chapman, C. Beggan, Wavelet and network analysis of magnetic field variation and geomagnetically induced currents during large storms, Space Weather (2021) doi: 10.1029/2021SW002772

 
Oxygen stable isotopes signals of the early Eocene growth of the Pyrenees: implications for steady-state and response time of mountain ranges
Authors: Castelltort Sebastien , Honegger Louis , Adatte Thierry , Spangenberg Jorge E. , Poyatos-More Miquel , Ortiz Alexandre , Curry Magdalena Ellis , Huyghe Damien , Puigdefebregas Cai , Garces Miguel , Vinyoles Andreu , Valero Luis , Laeuchli Charlotte , Nowak Andres , Fildani Andrea , Clark Julian D.
Published: March 2022

The topographic history of an orogen results from the interactions of climate and tectonics, and it can be reconstructed from the sedimentary record of its peripheral basins. Previous tectonostratigraphic studies, including flexural models, and sparse stable oxygen and carbon isotope data from the South-Pyrenean foreland basin suggest that a major period of topographic growth occurred in the late Paleocene-early Eocene. To further test this hypothesis, we present a stack of 658 stable isotope measurements on whole-rock marine carbonate mudstone from a 4800-m-thick composite sedimentary succession which provides a 12 Ma continuous record of environmental conditions during the early to middle Eocene (54 to 42 Ma). From the base of this record (at 54 Ma), oxygen isotopes  (δ18O values) show a faster decrease rate than the coeval global negative excursion associated with the Early Eocene Climatic Optimum (EECO). This local alteration of the global δ18O signal indicates that topographic growth during this period, associated with significant tectonic activity, perturbed the oxygen isotopic composition of foreland waters. Thus, our data suggest that significant topographic uplift of the Pyrenean orogen started from at least 54 Ma and continued until ca. 49 Ma, reaching the maximum elevations of 2000±500m in this phase from previous isotope and flexural studies. In addition, our record shows that the long-term carbon stable isotope composition during this period remained relatively stable with no similarity to the global bell-shaped long-term trend of the EECO. This is consistent with the restricted physiography of the South-Pyrenean foreland basin, mainly influenced by local sedimentary and water inputs. Overall, the Pyrenean topographic growth from the Late Cretaceous to the Miocene displays several growth stages that seem to be primarily determined by episodes of an increased rate of tectonic plate convergence. The duration of these growth stages (several millions of years) is possible documentation of the response time of mountain ranges to tectonic perturbations. The results of this work, therefore, demonstrate that stable isotope measurements on whole-rock sediments in foreland basins can provide key information for tectono-climatic and topographic reconstructions of mountain ranges.
Reconstruction of the Patagonian Ice Sheet during the Last Glacial Maximum using numerical modelling and geological constraints
Authors: Retamal-Ramírez Franco , Castillo Andrés , Bernales Jorge , Rogozhina Irina
Published: March 2022

During the Last Glacial Maximum (LGM, 23,000 to 19,000 years ago), the Patagonian Ice Sheet (PIS) covered the central chain of the Andes between ~ 38 °S to 55 °S. From limited paleoclimatic evidence, especially that derived from glacial landforms, it becomes clear that maximum ice sheet expansions in the Southern and Northern Hemispheres were not synchronized. However, large uncertainties still exist in the timing of the onset of regional deglaciation as well as its major drivers. Ice sheet modelling combined with glacial geochronology and paleoclimate reconstructions can provide important information on the PIS geometry, ice volume and its contribution to the sea level low during the LGM. It can also help to test different paleoclimate scenarios and identify climate models that capture regional climate responses to the global change in a realistic manner.

Here we present an ensemble of numerical simulations of the PIS during the LGM with an aim to constrain the most likely LGM climate conditions that can explain the reconstructed geometry of the PIS in a satisfactory manner. The PIS model is driven by the climate forcing that fuse near-surface air temperatures and precipitation rates from the ERA5 reanalysis with the paleoclimate model outputs from the Paleoclimate Modelling Intercomparison Project (PMIP2 and PMIP3) and the in-house Community Earth System Model (CESM) experiments. Our analysis suggests a strong dependence of the PIS geometry on the near-surface air temperature forcing. All the ensemble experiments designed with PMIP and in-house CESM experiments fail to reproduce the ice sheet extent between 38 and 42 °S. The most realistic performance for the LGM ice sheet extents south of 38 °S has been derived using those climate models that have a higher spatial resolution. The latter helps these models to capture regional climate conditions in a more physically consistent manner. It should be kept in mind that this analysis is based on the evaluation of the modelled ice sheet extents only, as geological evidence on the former ice sheet thickness is still scarce. Nevertheless, it can be shown that a realistic ice sheet geometry during the LGM is consistent with a regional decrease in air temperature of 7 to 12 °C and an increase in precipitation of 400 to 1500 mm/year along the western sectors of the PIS.
Rapid and temporary increases in low flows in the Amazon explained by changes in root-zone water storage
Authors: Nóbrega Rodolfo , Prentice Iain Colin
Published: March 2022

Increases in streamflow are often attributed to land-cover clearing (LCC) on the basis that it reduces soil infiltration capacity and increases surface runoff. Nonetheless, these changes can result from different hydrological mechanisms depending on the vegetation, and temporal and spatial scales. LCC triggers a series of changes in hydrological fluxes that have non-linear responses to precipitation and that were established upon the long-term balance with regional climatological, edaphic, and geological characteristics. We analysed streamflow and root zone water capacity (RZSC) to identify underlying relationships between stream dynamics and water consumption by plants. We used a time-series segmentation and residual trend analysis on streamflow and precipitation of high-order tributaries of the Tapajós River whose catchments underwent intense land-use changes over the past decades. We estimated the RZSC using the "Earth observation-based" mass-curve balance method by considering the annual land-cover changes over a >30-year period. We show that the reduction in the RZWC caused by changes in the water consumption by plants over the dry season is tightly associated with the increased baseflow contribution to rivers. Finally, we analysed gross primary productivity (GPP) and ET estimates generated by a model based on eco-evolutionary optimality that integrates the water and carbon cycles at the canopy level. We found that trends in ET from croplands are not as pronounced as trends in GPP. Although RZWC is quantified using the water deficit driven by ET, changes in RZWC are more correlated to changes in GPP. We show that the potential effects of vegetation responses to increasing atmospheric CO2 concentrations on streamflow are still outweighed by impacts of land-use change on low flows in Amazon rivers. However, this might not be the case for all water cycle components, and, therefore, we highlight the importance of considering the carbon cycle in hydrological assessment studies.
The Cadomian and Variscan record of the Gondwana margin in Israel: Protracted Crustal Evolution between the Arabian-Nubian Shield and multiple Tethyan Oceans
Authors: Abbo Avishai , Avigad Dov , Gerdes Axel , Morag Navot
Published: March 2022

The northern extent of the supercontinent Gondwana in the late Neoproterozoic-Cambrian is not well defined. In most localities the continental margin is covered by thick sedimentary successions, formed following the successive rifting of Tethyan Oceans that episodically detached continental terranes from the edge of the supercontinent. East of the Mediterranean, despite the continental continuity between the Arabian-Nubian-Shield (ANS) and the Tauride block (a Cadomian terrane), the original transition between the two crustal domains is inaccessible and remains obscured. In Israel, investigations of Late Ediacaran, late-stage igneous intrusions of the ANS in the South, together with granulite xenoliths from the lower crust in the North, allow us to probe into the North-Gondwana edge in the late Neoproterozoic and envisage its transition towards the peri-Gondwana Cadomian realm, as well as the evolution of the North Gondwana crust subsequently to the Neoproterozoic. Geochronology and isotopic geochemistry of alkaline intrusions in the Amram massif (southern Israel) as well as doleritic intrusions in the late Neoproterozoic Zenifim Formation (subsurface of south-central Israel) has revealed an igneous and thermal imprint at ca. 550 Ma recorded by the reset of apatite U-Pb ages, together with additional apatite U-Pb dates taken to represent crystallization. Nd and Hf isotopes in apatite, zircon and whole rock also show the ca. 550 Ma intrusions are isotopically distinct from the ANS and resemble Cadomian magmatism in the Taurides. Granulite xenoliths from the lower crust under the lower Galilee (North Israel) contain abundant zircons of distinct U-Pb-Hf properties. These include detrital grains remnant of Neoproterozoic sediment that was subducted and relaminated to the lower crust, late Carboniferous zircons (peaking at 300 Ma) with contrasting εHf(t) signatures, some of which represent syn-Variscan magmatism, and zircons with the age of the host Pliocene basalt. We demonstrate that the Cadomian (ca. 550 Ma) igneous and thermal imprint on the North ANS may have been driven by proto-Tethys subduction that brought about sediment relamination to the North Gondwana lower crust in the latest Neoproterozoic. The late Carboniferous ages recorded in the xenoliths involve both the reworking of depleted ANS basement as well as the relaminated sediment in the means of metamorphism and minor magmatism. Carboniferous thermal disturbance was associated with the formation of continental scale basin and swell architecture across present-day N Africa, Arabia and Iran, and the development of ‘Hercynian unconformities’ in these areas, that were located at the time south of the passive(?) margin of Paleo-Tethys.
Timing of incision of the western margin of the Colorado Plateau, new thermochronological data from Zion Canyon
Authors: Margirier Audrey , Thomson Stuart , Reiners Peter
Published: March 2022

The Colorado Plateau is a typical continental orogenic plateau characterized by a low-relief surface at high elevation that has been incised by the Colorado River system, forming outstanding canyons including the Grand Canyon and Zion Canyon. Although canyons are key features of ecosystems and water resources across the Colorado Plateau and form some of the most dramatic landscapes on Earth, the chronology of plateau uplift, subsequent canyon incision, and the controlling processes remain debated. The relative importance of mantle processes, tectonics, pre-existing geological structures, river drainage evolution, and climate remains controversial. Most studies addressing the timing of canyon incision and landscape evolution across the Colorado Plateau have focused on the Grand Canyon which shows the most spectacular incision with more than 1500 m of relief. Two end-member models of the Grand Canyon incision have been proposed: a 80-60 Ma incision or a 6-5 Ma incision. These models have important implications for processes driving Colorado Plateau uplift and incision, and for feedbacks on regional climate. However, studies quantifying the timing of canyon incision and surface uplift are lacking in other areas of the plateau. We used apatite fission-track and (U-Th-Sm)/He analysis to infer the incision history of Zion Canyon by the Virgin River on the Western margin of the Colorado Plateau. These low temperature thermochronological systems are sensitive to temperature ranging from 120 to 50°C. Despite the canyon only being a maximum of ~1 km deep, a high local geothermal gradient of >50°C / km means these thermochronometers provide a record of the timing of this incision. Preliminary inverse thermal modelling of apatite fission-track and (U-Th-Sm)/He data suggest reheating following Jurassic deposition to maximum temperatures of ~70-80 °C during the later Cenozoic, with onset of incision-related increased cooling rates in the last 10 Ma. Our results are in agreement with the recent work of Walk et al. (2019) indicating incision by the Virgin River during the last 4 to 3 Myr in the Zion area. Together with existing structural cross-sections and reconstructions of the timing of surface uplift and incision by the Virgin River in the Zion area, our thermochronological data support that Zion Canyon was carved since the late Miocene following tectonically driven rock and surface uplift along the western edge of the Colorado Plateau.  
MJO-induced land-atmosphere feedbacks across East Africa
Authors: Talib Joshua , Taylor Christopher , Wainwright Caroline , Harris Bethan
Published: March 2022

Across East Africa, sub-seasonal rainfall variability predominately depends on the phase of the Madden Julian Oscillation (MJO). Rainfall is enhanced during MJO phases 2 to 4, and suppressed during phases 6 to 8. Given that MJO-induced anomalous precipitation can persist beyond several days, a significant surface response is expected. Using earth observations and reanalysis data, this work illustrates how MJO-induced precipitation anomalies promote a surface response which feeds back onto local and regional atmospheric conditions.

                MJO-induced rainfall suppression across East Africa decreases surface soil moisture across semi-arid regions including southern South Sudan, western Kenya and northern Uganda. In regions predominately covered in grass and cropland, reduced soil moisture increases surface sensible heat fluxes and elevates land surface temperatures. A drier and warmer surface promotes an increased boundary-layer height and reduces surface pressure. We identify that spatial variations in the surface response to MJO-induced anomalous precipitation, impacts the intensity of the Turkana jet. Across southern South Sudan and in the exit region of the Turkana jet, reduced soil moisture increases land and near-surface temperatures, whilst in north-east Kenya and in the entrance region of the jet, no land surface temperature response is observed. The difference in surface response between the jet entrance and exit regions increases the pressure gradient along the Turkana channel, and thus intensifies the jet. Since the intensity of the Turkana jet controls the transportation of moisture from low-lying regions of East Africa into Central Africa, we highlight that surface-induced variations in jet intensity impacts rainfall totals across East Africa. Furthermore, due to the Turkana jet response to spatial variations in surface warming, we also identify that the magnitude of MJO-induced anomalous precipitation is influenced by surface conditions prior an MJO event. For example, when the surface over southern South Sudan is anomalously dry, MJO-induced precipitation suppression is greater. This presentation will highlight that to fully exploit predictability from the MJO, forecast models must correctly represent surface processes and land-atmosphere interactions. Future work evaluating sub-seasonal forecast models and improving the representation of land-atmosphere interactions will enhance the lead-time of early warning systems.
Plastics Gone Missing: Resolving the Mass Balance at River Bifurcations
Authors: Thi Khoa , van Emmerik Tim , Hoitink Ton , Quy Pham Nhan
Published: March 2022

Recent studies suggest that more land-based plastics are accumulated and remobilized in riverine environments than exported to the ocean. Hydrodynamics and other factors like wind drag and navigation can drive plastics to riverbanks, where they can be retained in plants, on floodplains, or in stagnant water bodies. With this study, we provide additional observational evidence that a substantial share of floating plastics may not flow downstream. Every week from May to December 2021, we measured floating plastics at three bridges located in the Hong-Duong bifurcation of the Red River, Vietnam. These locations were chosen to monitor both the input plastics entering the bifurcation and the output plastics exiting the bifurcation in both branches. The upstream location is Nhat Tan, which is located on the Red River in northern Hanoi. The downstream location on the main stream is Long Bien, approximately 8 kilometers south of Nhat Tan on the Red River, while the third location is in Dong Tru, on the distributary Duong River, about 7 kilometers from Nhat Tan. We collected data on the plastic mass balance of various plastic categories in the bifurcation, including PET, PO-soft, PO-hard, multilayers, PS, and PS-E. The results indicated that the plastic mass balance does not close in general; there is more plastic upstream than in the two downstream locations combined. The dry season, from October to December, was more balanced, with a 4% difference. Meanwhile, between May and September, approximately 16% of floating plastics were discovered to be missing. Additionally, the majority of floating plastics remained in the main stream, with only 8% entering the distributary, and the division rate kept constant throughout the study period. However, the balance differed for specific categories. Five categories had missing downstream records compared to upstream, and PO-soft featured a more intricate balance mechanism with alternating changes between missing and abundant records from month to month. In the meantime, PS was seen upstream but was never detected downstream. For PS-E, most of the items found in the upstream were either detected in the distributary, or disappeared in the bifurcation; less than 1% was identified downstream. The variation in transport between PS and PS-E may be caused by deposition, extraction, accumulation, or sub-surface transport. Finally, except for PO-hard, the rate of plastic transport was found to be higher near the river banks than in the thalweg. These findings suggest that the transport mechanism of macroplastics in rivers may be more complex than previously assumed, and prompt further studies. Our data allow modelling plastic transport for different plastic categories, designing suitable monitoring or clean-up methods, and understanding the roles of hydrological components such as discharge and flow velocity in transporting plastics.
Changes to the Earth’s energy budget due to global forestation and deforestation affect remote climate via adjusted atmosphere and ocean circulation
Authors: Portmann Raphael , Beyerle Urs , Davin Edouard , Fischer Erich , De Hertog Steven , Schemm Sebastian
Published: March 2022

Recent controversies about the climatic consequences of forestation and deforestation have centered on the carbon storage potential of forests and the local or global thermodynamic impacts due to biogeophysical effects. So far, not much attention has been given to the changes that biogeophysical effects of forestation and deforestation impose on the atmospheric and ocean circulation and consequently on remote weather and climate.  Here we discuss how the changes in the Earth's energy balance following global-scale forestation and deforestation alter the global atmospheric circulation patterns and even have profound effects on the ocean circulation. We perform multicentury coupled climate model simulations in which preindustrial vegetation cover is either completely forested or deforested and carbon dioxide mixing ratio is kept constant. Forestation leads to global warming of +0.5 K, which is most pronounced over northern extratropical land. Consequently, the meridional heat transport in the Northern Hemisphere decreases in the forestation simulation. The reduction mainly occurs in the ocean as a result of a weakened Atlantic meridional overturning circulation (AMOC). Extratropical land-warming results further in weaker and poleward shifted weather systems, which, via momentum feedback to the mean flow leads to an attenuation and poleward displacement of the extratropical jet stream. Deforestation leads to global cooling of -1.6 K, a stronger AMOC and extratropical jet stream, a southward shift of the intertropical convergence zone and a stronger Hadley cell in boreal winter, and a weaker Hadley cell in boreal summer. In many aspects, deforestation causes the reverse patterns compared to forestation but with larger amplitudes. These larger amplitudes are mostly related to a strong snow-ice-albedo feedback in high latitudes. Both land surface changes substantially affect regional precipitation, temperature, and surface wind patterns across the globe. The design process of large-scale forestation projects thus needs to take into account global circulation adjustments and their influence on remote climate.