bluuebunny/crossref_metadata_2025 huggingface dataset:
Density, temperature and composition of Antarctica’s lithosphere and impact on geothermal heat flux and mantle viscosity
Authors: Li Lu , Aitken Alan , Gross Lutz , Codd Andrea
Published: February 2023

A knowledge of Antarctica’s lithospheric properties is essential for understanding tectonic history and solid-earth influences on ice sheet dynamics. For example, the spatial variation of mantle temperature impacts both geothermal heat flow and mantle viscosity, which influence the ice sheet basal melt rate and glacial isostatic adjustment. Seismic tomography models can be used to constrain the mantle temperature. However, seismic velocity to temperature conversion is sensitive to variations in mantle composition, which are linked to changes in density that are also resolved in the gravity field.Here we model Antarctica’s density distribution using a 3D finite element gravity inversion approach based on the esys-escript model in python. We derived a correction to an initial density distribution based on a seismic tomography model (ANT-20). From the resulting density distribution and the initial seismic velocity distribution we estimated mantle temperature and composition and calculated the lithosphere thickness, mantle viscosity, and geothermal heat flow. The result shows that East Antarctica has a dense, thick (>150 km) and cold lithosphere, whereas West Antarctica has a thin (<100 km) hot lithosphere. The new heat flow model suggests a higher heat flow estimation than previous continental scale estimations.Our result highlights compositional heterogeneity within East Antarctica, with a highly depleted cratonic mantle in central East Antarctica. By considering compositional change, modelled mantle temperature increases up to 150 °C in depleted regions to accommodate lower density with fast seismic velocity. Higher modelled temperatures cause reduced lithospheric thickness up to 80 km compared with the initial model. In comparison to previous results in interior East Antarctica, a 5-10 mW/m2 higher heat flow is suggested by our model. In West Antarctica, large areas show heat flow of up to 110 mW/m2. Our result also suggests low mantle viscosity including Amundsen Sea Embayment, Marie Byrd Land and Antarctic Peninsula.
Causal Mechanisms of Rising Sea Level and Increasing Freshwater Content of the Beaufort Sea
Authors: Fukumori Ichiro , Wang Ou , Fenty Ian
Published: February 2023

Over the last two decades, sea-level across the arctic’s Beaufort Sea has been rising an order of magnitude faster than its global mean. This rapid sea-level rise is mainly a halosteric change, reflecting an increase in Beaufort Sea’s freshwater content. The rising volume of freshwater is greater than that associated with the Great Salinity Anomaly of the 1970s, raising the prospect of future disruptions in large-scale ocean circulation and climate. Here we provide a new perspective of this Beaufort Sea variation using a global data-constrained ocean and sea-ice model of the Estimating the Circulation and Climate of the Ocean (ECCO) consortium. Causal relationships are quantified using the model’s adjoint. Controlling processes are elucidated analyzing property budgets.The study reveals the multi-decadal variation to be driven jointly by change in wind stress and sea-ice melt. Strengthening anticyclonic winds surrounding the Beaufort Sea intensify the ocean’s lateral Ekman convergence of relatively fresh near-surface waters. The strengthening winds also enhance convergence of sea-ice and ocean heat that increase the amount of Beaufort Sea’s sea-ice melt. Whereas the region’s direct wind-driven kinematic anomalies equilibrate over weeks, sea-ice-melt-driven diabatic changes persist for years owing to Beaufort Sea’s semi-enclosed gyre circulation. The growing disparity between where sea-ice forms and where it melts results in this rare example of melting floating ice causing large-scale sea-level rise. The spin-up difference suggests that, on their own, the sea-ice-melt-driven diabatic change will last much longer than the direct wind-driven kinematic anomaly.The study highlights the importance of observations and the utility of ECCO’s modeling system. While ocean and sea-ice observations are essential in diagnosing the change, the study also points to a need for expanded observations of the atmosphere, especially the winds that act on the ocean/sea-ice system. ECCO is implementing a novel “point-and-click” interface for analyzing its modeling system, such as conducted here, without requirements for expertise in numerical modeling, and invites exploitation of its new utility (https://ecco-group.org).
Humankind, Energy and the Climate - A EURO-CORDEX Analysis
Authors: Schlott Markus , El Sayed Omar , Bilousova Mariia , Li Chen , Guidi Filippo , Kies Alexander , Stöcker Horst
Published: February 2023

Climate change is going to alter the appearance of planet Earth throughout the century and beyond unprecedentedly. Therefore the United Nations (UN) decided to classify climate action as the 13th Sustainable Development Goal (SDG); right after the fight against poverty, hunger and other emphases. With the Paris Agreement from 2015, the world community finally got through to tackle this crisis in an ambitious step forward, aiming at a global warming rate of well below 2°C. However, it is by far not clear, how this task can be achieved in an economically sensible way; especially with regard to the first twelve SGDs, and, in addition to this, an ever increasing world population with around eleven billion human beings at the end of the century. This dilemma makes clear: future action against climate change must also develop solutions to the social questions from nowadays. But even more: it must be thought in a broader context, regarding energy security, population dynamics, economic transformation processes, as well as the general standard of living.The presented work is the first part of a study that addresses these questions for Europe by cost-optimizing a sector-coupled network model of its energy system (PyPSA-Eur-Sec), done under two main aspects: first, the impact of climate change on the energy related infrastructure, and second, the role of socio-economic uncertainties in form of boundary conditions. The first is achieved by invoking all energy relevant meteorological weather data variables from the EURO-CORDEX climate projections. The second is based on social and economic projections such as the World Population Prospects from the UN Population Division.The results from part one are given by an energy-meteorological analysis of the full EURO-CORDEX ensemble, covering three distinct greenhouse gas emission scenarios: RCP2.6, RCP4.5 and RCP8.5. The analysis investigates the power output from wind turbines (sfcWind, rlst), solar panels (hurs, rsds, rsus, tas), and hydro plants (mrro, orog); each time for the EUR-11 domain and at the end of the century in form of a last-year approach. The resulting fields are evaluated in two ways: in comparison to each other, quantifying the uncertainties among the different climate models, and in comparison to today’s climate status quo with respect to the ERA5 reanalysis, quantifying any impact of climate change on the variables and their related power potentials.
Atmospheric weather patterns and their contributions to the fall stratification breakdown on the Southern New England shelf
Authors: Lobert Lukas , Gawarkiewicz Glen , Plueddemann Al
Published: February 2023

High-wind events predominantly cause the rapid breakdown of seasonal stratification on mid-latitude continental shelfs. It is well established that downwelling-favorable wind forcing, i.e., wind vectors with the coastline to their right (on the northern hemisphere), leads to enhanced coastal destratification. A categorization scheme for high-wind events has identified the two atmospheric weather patterns that locally cause such favorable wind conditions on the Southern New England shelf and have the largest contribution to the annual breakdown of stratification in the region. These patterns are i) cyclonic storms that propagate south of the continental shelf and cause strong anticyclonically rotating winds, and ii) persistent large-scale high-pressure systems over eastern Canada causing steady north-easterly winds. Despite both patterns generally producing downwelling-favorable winds on the shelf, the two patterns differ in their wind direction steadiness and tend to produce opposite temperature and salinity contributions to destratification, implying differences in the dominant processes driving ocean mixing. We hypothesize that local mechanical mixing and surface cooling dominate for cyclonic storms due to their strong wind energy input and shear production. In contrast, the weaker but steady downwelling-favorable winds from high-pressure systems can lead to an enhanced cross-shelf Ekman cell that advects salty and less buoyant Slope Water onto the continental shelf. To assess which process dominates for the different impactful high-wind event patterns, we apply a simplified two-dimensional mixed-layer model framework that incorporates horizontal buoyancy gradients across the shelfbreak front. The model allows to determine the stratification change caused by one-dimensional surface forcing (wind stress and surface buoyancy flux) and Ekman-driven advection individually. Observations from moorings and glider transects across the shelfbreak, provided by the Ocean Observatories Initiative Coastal Pioneer Array (2015-2022) at the Southern New England shelfbreak, allow a comparison to investigate the importance of along-shelf processes for predicting shelf stratification changes on synoptic to intra-seasonal timescales.
Typical Synoptic Weather Patterns Responsible for Summer regional Hourly Extreme Precipitation Events over the Lower Yangtze River Basin, China
Authors: Huang Anning
Published: February 2023

Hourly gauge rainfall measurements and ERA5 reanalysis for the period 1980-2020 are used to identify typical synoptic weather patterns responsible for summer regional hourly extreme precipitation events over the lower Yangtze River basin. It turns out that the Meiyu front or cyclonic shear imbedded in the East Asian summer monsoon (EASM) and landfalling typhoons are the leading contributors. As the dominant synoptic pattern, the EASM accounts for ~93% occurrence of regional hourly rainfall extremes. The double peak diurnal occurrence (morning and late afternoon) of rainfall extremes corresponds to the Meiyu front and cyclonic shear driven by a strengthened and westward extended western North Pacific subtropical high and accelerated low-level southwesterly flow. During 1980-2020, there was a clear increasing trend in the occurrence of regional hourly rainfall extremes over the region. These findings are beneficial to the prediction and risk assessment of extreme rainfall events over the specific region. 
Predicting Greenland Ice Albedo Using A Physically-Based Convolutional Long Short-Term Memory Network
Authors: Antwerpen Raf , Tedesco Marco , Gentine Pierre , Alexander Patrick , van de Berg Willem Jan
Published: February 2023

Global mean sea level rise has been accelerating significantly over the past decades, a substantial part of which is attributed to increased surface melting from the Greenland ice sheet (GrIS). Climate models project the GrIS to contribute 9-18 cm to global mean sea level rise by 2100 for the Shared Socioeconomic Pathway SSP5-8.5. The significant uncertainty in this projection prevents accurate mitigation of the effects of sea level rise. The uncertainty stems from a not-comprehensive understanding of the physical processes controlling surface melting. In particular, we lack understanding of ice albedo evolution/variability, a crucial factor in surface melt processes. Ice albedo is a complex and highly variable property of the ice surface that is not well represented in climate model projections, leading to imprecise predictions of sea level rise. The high complexity and number of drivers and feedbacks responsible for ice albedo variability prevent us from building a comprehensive predictive ice albedo model that accurately incorporates all these processes.From this point of view, we adopt a machine learning-based approach to predict ice albedo variability on the GrIS. We use daily regional climate model output of atmospheric, radiative, and glaciological variables from the Modèle Atmosphérique Régional (MAR) as input data and daily broadband albedo data from the Moderate Resolution Imaging Spectroradiometer (MODIS) as output data. From these data, we construct a Convolutional Long Short-Term Memory (CNN-LSTM) network that models daily ice albedo variability on 6.5 km spatial resolution. A CNN is a neural network that works particularly well for extracting patterns from spatial data. An LSTM is a special kind of recurrent neural network (RNN) that is well-suited for finding patterns and trends in temporal data on a much longer time scale than classic RNNs. Preliminary results show a significant improvement of the correlation between observed and simulated bare ice albedo, with the CNN-LSTM outperforming MAR. Besides the predictive ability of this physically-based machine learning ice albedo model and its suitability for implementation in climate models, it also allows us to gain understanding of what variables drive ice albedo variability on the GrIS, now and in the future.
Geoheritage inventory in southwest Goiás, Brazil: a first step to disseminate geodiversity and its association with culture
Authors: Maciel Lima Andréa , de Lima Cláudia Valéria , Pereira Paulo
Published: February 2023

Geoheritage is the part of geodiversity constituted by the natural abiotic elements that must be conserved due to its heritage value. In this work, the first results on the study of the geodiversity and the geoheritage of the southwest Goiás micro-region, in Brazil, are presented. This region is composed by 18 municipalities characterized by the agricultural and cattle-raising activities that stand out in the Brazilian Centre-West. Plateaus dominate the landscape, corresponding to the northern limits of the Paraná Sedimentary Basin in the state of Goiás, covering one of the marginal sections of this Palaeozoic and Mesozoic age basin. Two geomorphological sub-units are differentiated by altimetric unevenness and erosive processes that originated different types of dissection: Rio Verde Plateau and Caiapônia Plateau, separated by an alignment of ridges, called Serra do Caiapó. Public incentives and investments and the low price of land caused a wave of migration of rural landowners and producers from the South and Southeast regions to the Southwest of Goiás. The plateaus with low slope and soil corrections contributed to the mechanization of the field which were crucial to its agricultural occupation. The scenario of high productivity remains until today, indicating the great intensity of the dynamics of land use and occupation. In order to disseminate geodiversity and geoheritage concepts and to promote initial stages of a geoconservation and geotourism strategy, an inventory was carried out. Through documental research and field work, an assessment was made, comprising the identification of different sites typologies, use values, degradation risk and relevance of potential geosites. 42 potential geosites classified by their geomorphological (16), hydrogeological (15), paleontological (3), lithological (2), pedological (2), paleoenvironmental (2), mining (1) and tectonic-structural (1) interest have been inventoried. The area includes a portion of the Araguainha Astroblema, a geosite of international relevance and the Emas National Park, since 2001 a UNESCO World Heritage Site. Archaeological sites identified in the municipalities of Caiapônia and Serranópolis were also considered, due to the strong association of cultural value with local geodiversity. The area has great potential for geoheritage dissemination, with different types of interest and use values. Geodiversity supported the development of human activities since thousands of years ago, evidenced in the rocks through paintings and rock carvings or in recent activities such as agriculture. It is intended that these data may serve as a contribution to geoconservation and geotourism strategies based on the geoheritage value and its strong relationship with cultural elements.
Geochemical and microbial characteristics of authigenic carbonates from the Chukchi Borderlands in the western Arctic Ocean
Authors: Kim Jung-Hyun , Lee Dong-Hun , Lee Yung Mi , Bayon Germain , Kim Dahae , Joe Young Jin , Wang Xudong , Shin Kyung-Hoon , Jin Young Keun
Published: February 2023

Migration of methane-rich fluids at submarine cold seeps drives intense microbial activity and precipitation of authigenic carbonates. In this study, we investigated authigenic carbonate samples taken from active gas hydrate mounds on the southwestern slope of the Chukchi Borderlands (CB), western Arctic Ocean. Our main objectives were to characterize the distribution patterns of trace elements in carbonate-hosted lipid fractions and to assess metalloenzyme requirements of microbes involved in anaerobic oxidation of methane (AOM). We measured stable isotopes, trace elements, lipid biomarkers, and genomic DNA. Our results indicate the dominance of AOM-related lipid biomarkers in studied carbonate samples, as well as a predominant occurrence of the anaerobic methanotrophic archaea (ANME)-1. We also report evidence for significant preferential enrichments of various trace elements (Li, Ni, Co, Cu, Zn, and Mo) in the total lipid fractions of CB carbonates, relative to elemental compositions determined for corresponding carbonate fractions, which differ from those previously reported for other seep sites. We hypothesize that trace element enrichments in carbonate-hosted lipid fractions could vary depending on the type of AOM microbial assemblage.
The role of future aridification in multi-year drought persistence for global hydrologic basins
Authors: Bjarke Nels , Livneh Ben , Barsugli Joseph
Published: February 2023

Increasing aridity is a growing concern for many regions across the globe, primarily driven by an alteration to the balance of evaporative loss and incoming precipitation. While this is likely to drive declines in the long-term mean of surface water, interannual and decadal variability of precipitation will still produce wet and dry periods. Yet, the potential increase in the occurrence of multiple sequential drought years is of particular concern especially for basins without substantive water shortage infrastructure. In this presentation, we evaluate the enhanced likelihood of multiple consecutive , i.e. years with below 20th percentile annual runoff, occurring within large basins (25,000-150,000 km­2) across the globe that are projected to experience increasing aridity within an ensemble of 16 CMIP6 general circulation models. We use historical simulations (1950-2014) and future projections (2015-2100) from three emission scenarios to demonstrate how aridification, as measured by increases in the long-term ratio of potential evapotranspiration and precipitation, is expected to change. We examine the ways in which changes in aridity paired with projected changes to the interannual variability of precipitation can conspire to enhance the probability, magnitude, and persistence of multi-year drought.
Erosion and sedimentation as drivers of dynamic geodiversity
Authors: Zwoliński Zbigniew
Published: February 2023

Dynamic geodiversity is the study of the ongoing changes in the Earth's geological, geomorphological, climatic, hydrographical/hydrological, and pedological processes, features and landscapes. It encompasses both natural processes, such as erosion and sedimentation, as well as human activities that can impact the Earth's geology or geography, such as mining or land use change. Understanding dynamic geodiversity is important for predicting and managing the impacts of these changes on the environment and further as a consequence on human societies.There are a few examples of dynamic geodiversity:Volcanoes and earthquakes: These geologic events can dramatically alter the landscape and have significant impacts on the environment and human communities.
Erosion and sedimentation: these processes shape the Earth's surface and create diverse landscapes, such as mountains, valleys, and coastlines.
Climate change: Changes in the Earth's climate can lead to shifts in the distribution of landscapes, as well as changes in the timing and intensity of geological and geographical processes, such as landslides and coastal erosion.
Land use change: Human activities, such as urbanization, agriculture, and resource extraction, can have significant impacts on the Earth's surface and the diversity of its features and processes.
Dynamic geodiversity is important for understanding the Earth's environment and its diversity. Examples of erosion and sedimentation processes that change the face of the Earth will be shown during the presentation
Intelligent coordinated control technology of dust-gas in underground excavation face in highly gas mine, China
Authors: Cao Yong , Xiao Yang , Wang Zhenping , Li Qingwei
Published: February 2023

As a chronic hazard, coal mine dust is widely distributed in mines around the world, especially in China, and the number of cases of pneumoconiosis caused by coal mine dust remains high every year. In highly gas mines, excavation work is at risk of exceeding gas concentrations, which could cause gas-coal explosions under certain conditions. The underground excavation face of the high gas mine urgently needs to solve the gas overrun problem caused by dust prevention and control work. In this work, gas-coal dust monitoring and early warning technology was used, to establish a treatment concept combining intelligent wind control and dust removal and gas overrun prevention and control. Via numerical simulation with FLUENT, to determine the air volume ratio of gas over limit prevention and control, the optimal dust removal air volume ratio, and applied in the field. The results indicated that the intelligent wind control technology had a excellent prevention effect on the problem of dust-gas coexistence.
Testing the Sensitivity of Shear Wave Splitting to Volcanic Inflation, A Case Study from Askja, Iceland
Authors: McCann Jamie , Winder Tom , Bacon Conor , Rawlinson Nicholas
Published: February 2023

Askja is an active volcano situated in the Northern Volcanic Zone of Iceland that last erupted in 1961. Since then, long-term geodetic studies of Askja’s caldera complex have tracked the deflation at a decaying rate associated with a shallow source. However, in August 2021, a rapid reversal of this trend indicated the onset of re-inflation, which, as of January 2023, has resulted in 45cm of uplift near the centre of the primary caldera. While several techniques have been used to measure the geodetic signal associated with this inflation, including gravity and InSAR data, there has yet to be a detailed examination of the seismic response. We observe a definitive increase in the rate of seismicity associated with the onset of re-inflation in August 2021. In this study we examine the sensitivity of shear wave splitting, a phenomenon arising due to seismic anisotropy in the crust, to the changing stress state of the crust within and surrounding Askja associated with this new phase of inflation. We estimate the fast orientation and delay time, which parameterise the orientation and magnitude of seismic anisotropy respectively, from split shear wave arrivals across our local network of seismometers. We leverage an extensive catalogue of microearthquakes in and around Askja spanning 2007 to 2022 in order to compare the variation in pre- and post-inflation delay times and strength of anisotropy, to better understand the sensitivity of shear wave splitting to stress changes during periods of volcanic inflation. This will give valuable information on whether shear wave splitting can be used as a proxy for stress changes when other geodetic observations cannot be performed in volcanic and other settings, as well as the role shear wave splitting has in combination with these other techniques.
Deposition of tillites and cap carbonates in NW Tarim, China: Implications for chemical weathering following the Marinoan deglaciation
Authors: Lu Lihui , Han Yigui , Zhao Guochun , Wang Zhenfei , Ju Pengcheng , Cao Xuyang
Published: February 2023

The formation of Neoproterozoic tillites and overlying cap carbonates is important to understand drastic climatic and paleo-environmental variations during and after the collapse of the Snowball Earth. This rock assemblage has been found at the northwestern margin of the Tarim Craton in China but its depositional processes are still debated. We carried out stratigraphic and carbon isotopic studies on the tillites of the Yuermeinak Formation and overlying cap carbonates in this area. Detailed field observation and stratigraphic comparison demonstrate that these strata formed around the age of Marinoan deglaciation (ca. 635 Ma). Unconformable contacts with bedrocks and the variation of dip directions of the cap carbonates suggest that a mountainous topography developed in northwest Tarim during the Marinoan glaciation. We proposed a four-stage depositional model from glacial to alluvial fan and/or neritic facies systems. The first stage formed the stratified and massive tillites, recording several glacial cycles during the Marinoan deglaciation. The second stage involved the belated transgression at the end of the Marinoan deglaciation, caused the re-cementation of some tillites and the negative δ13C of their matrixes. The third stage included the alternating precipitation of calcareous mudstones and cap carbonates after the Marinoan deglaciation, reflecting frequent sea-level changes. The fourth stage was relevant to a terrestrial environment because of a widespread marine regression. Furthermore, we suggest that the timespan of the intense chemical weathering on exposed continents after the Marinoan deglaciation was comparable to the duration of the transgression, lasting for hundreds of thousands of years. This work was financially supported by NSFC projects (grants 42072264, 41730213, 41902229, 41972237) and Hong Kong RGC GRF (17307918).
Sensitivity Analysis on Sea Surface Drag Parameterization in Storm Surge Modeling
Authors: Özkan Feyza Nur , Verlaan Martin , Muis Sanne , Zijl Firmijn
Published: February 2023

Storm surges can be described as nonperiodic fluctuations in sea levels associated with variations in wind stress and atmospheric pressure, caused by the approach of cyclones or extratropical storms. They can have catastrophic results on coastal communities, particularly in combination with high tides and large waves. Therefore, for the efficiency of storm surge modeling, the accuracy and resolution of meteorological data as well as hydrodynamic processes, which are essentially governed by the atmospheric flow under such strong wind conditions, are particularly crucial. In addition to the accurate forecasts of wind speed, there is uncertainty in translating wind speed to the wind shear stress, which is an essential contributor to storm surges that quantify the driving force of wind to ocean flow using a sea-surface drag in the numerical models.The main purpose of this study is to improve our understanding of the role of sea surface drag parametrization in storm surge dynamics and reproduction within the Global Tide and Surge Model (GTSM). The depth-averaged hydrodynamic model GTSM, which has global coverage and spatially varying resolution increasing towards the coast, can be used to simulate changes in water levels and currents caused by tides and storm surges. In this study, the GTSM is used to compute tide and surge combined to provide accurate tide-surge interactions, and we conduct a sensitivity study of the storm surges to evaluate the performance of various sea surface drag parameterization in predicting storm surge behavior to determine the most suitable one. The model's performance is assessed based on a comparison of modeled and observed storm surges, both being estimated based on tidal analysis of total water levels. We investigate the performance from 2006 to 2022 and analyze 20 specific extreme weather events, such as extra-tropical storm Xaver that occurred over the North Sea and post-tropical cyclone Fiona hit Canada. The results of this study will provide valuable insights into the most suitable sea surface drag parameterization for the prediction of tide-surge interactions, surge signal's mean behavior, and storm surge dynamics within the GTSM under storm conditions.
Assessing the added value of Aeolus winds in the ECCC forecast system
Authors: Chou Chih-Chun (Gina) , Kushner Paul J. , Laroche Stéphane
Published: February 2023

The European Space Agency (ESA)’s Aeolus mission, launched in August 2018, provides the first global horizontal line-of-sigh (HLOS) wind profile measurements. Many Numerical Weather Prediction (NWP) centres, including ECMWF, DWD, Météo-France, Met-Office and ECCC, have shown that assimilating Aeolus winds improves overall forecast skill, especially in the tropics and data-sparse regions. To better characterize the locations and drivers of improved skill from Aeolus, we use a series of Observing System Experiments (OSEs) with the ECCC Global Deterministic Prediction System (GDPS) covering the period July to September 2019 and December 2019 to March 2020. Three experiments are used: CNTRL, CNTRL+Aeolus, and CNTRL-winds. All the observations assimilated in the GDPS are included in the CNTRL experiment. The Aeolus winds are added in the CNTRL+Aeolus experiment and the operational wind observations are withheld in the CNTRL-wind experiment. The impact of the operational winds and Aeolus are quantified by comparing the forecast error of the CNTRL-winds and CNTRL experiments with the CNTRL and CNTRL+Aeolus experiments. As expected, the operational winds improve the tropospheric forecast over the tropics the most, with a normalized forecast error of 8% for the wind field. By adding the Aeolus winds, which account for less than 1% of the observations, the tropospheric forecast further improves by 0.7-0.9% over the tropics and the Arctic, and by 0.5-0.6% over the data-sparse Southern Hemisphere extra-tropics. The added value of Aeolus winds is further highlighted when its impact on forecasts as a function of length scale is investigated, using a spherical harmonic decomposition. The impact is measured as the difference of the 250-hPa kinetic energy forecast error spectra between experiments. The impact of operational winds and Aeolus is dominated by the transient component whose impact is nearly four times greater than the impact on the mean component. The operational winds largely improve the forecast of global scale to intermediate scale in the short-range forecasts. The impact then decreases as forecast range increases. On the other hand, the impact of Aeolus is mostly seen in the intermediate to large scale range with a peak around spherical harmonics of degree 9 (scales about 4000 km), and is the smallest on day 1 and increases until days 4 to 5. This analysis suggests that Aeolus winds provide estimates of the wind state that are valuable and complementary to that provided from current operational winds.
Biodiversity conservation and ecosystem restoration to meet the Kunming-Montreal Global Biodiversity Framework and satisfy climate goals of the Paris Agreement
Authors: Park Hun , Song Cholho , Choi Hyun-Ah , Lee Woo-Kyun
Published: February 2023

The remaining carbon budget for curbing climate change according to the Paris Agreement can be depleted within only less than a decade or at most a few decades if the current emissions trend continues. Many ideas and policies have been proposed to reduce carbon emissions. However, the importance of biodiversity conservation and ecosystem restoration has not been properly empirically underscored.According to the latest Living Planet Report, between 1970 and 2018, the average abundance of 31,821 populations of 5,230 species monitored worldwide declined by 69% (63–75%). When living organisms die and decompose, they can only increase CO₂ in the atmosphere or further acidify the oceans. Therefore, maintaining an abundance of living organisms can help global climate action.And while plants are the largest reservoirs of carbon (450 billion tonnes), they are not the only ones. For example, bacteria (70 billion tonnes) and fungi (12 billion tonnes) contain far more carbon than the entire animal kingdom (2 billion tonnes). If we can increase or at least conserve the biomass of living organisms, we can maintain living carbon stocks, avoiding additional carbon emissions from local extinctions or, in the long run, extinction of the species itself. That’s why biodiversity conservation and ecosystem restoration could fill in the last blank on achieving carbon neutrality.In this regard, this study investigates how environmental degradation as well as changing land and ocean use disrupt the global carbon cycle from the conservation biology perspective.Using the levels of success to meet the goals and targets of the Kunming-Montreal Global Biodiversity Framework (GBF) adopted by 196 parties of the Convention on Biological Diversity in December 2022, this study estimates the expected carbon storage gains. Policy implications in relation to the GBF and the Enhanced Transparency Framework of the Paris Agreement are also discussed.Acknowledgement:This research was supported by the Core Research Institute Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A1A10045235).
On-orbit Calibration of GRACE and GRACE-FO accelerometers
Authors: Tzamali Myrto , Pagiatakis Spiros
Published: February 2023

The onboard GRACE and GRACE-FO accelerometers measure the non-gravitational accelerations of the spacecraft that are indispensable for the modelling of the Earth’s gravity field since they are subtracted from the GPS POD total accelerations to isolate the pure gravitational accelerations. The accelerometers, like any other instrument, must be calibrated very accurately to serve their purpose but the calibration cannot be done as per standard metrological methods, in a laboratory environment due to the influence of the gravitational signal which is almost 10 orders of magnitude larger. Many researchers have proposed different approaches for the estimation of the bias and the scale factor of the accelerometers, most of which are based on the physical models of the non-gravitational accelerations The drawback of these methods is the dependency of the calibration on the theoretical models and specifically on the drag models that exhibit the highest uncertainty due to the complexity of the upper atmosphere. An alternative, on-orbit calibration of the accelerometers is proposed that is commensurate with standard metrological methods and thus it is based only on the satellite measurements. The idea behind this method lies in a time-reversal method widely used in radar applications for the detection and measurement of known but distorted pulses hidden in the scattered signal from the reflectors. By analogy to radar applications, the total accelerations estimated from GPS through numerical double POD differentiation, correspond to the ‘transmitted signal’ (calibrated) and the accelerometer measurements (uncalibrated) comprise the ‘return signal’ (scattered signal).  The key to this method is that the penumbra transitions are present in both signals and play the role of the known calibration pulse. Examples of 30 daily scale factors are calculated for different operational periods during lower and higher solar activity of GRACE and GRACE-FO and the accelerometer bias is computed by a daily polynomial fit. The results show a robust estimation of the scale factor and bias of the accelerometers. The thermal sensitivity of the accelerometer and its correlation with the β’ angle is investigated. 
A matched filter approach for the calibration of GRACE and GRACE-FO accelerometers.
Authors: Pagiatakis Spiros , Tzamali Myrto
Published: February 2023

For the accurate determination of the gravity field of the Earth, the accelerometers on board GRACE and GRACE-FO missions need to be calibrated, which is a rather challenging task. In many gravitational field studies, the bias and scale factors are introduced, among others, as unknown parameters in the gravity field recovery process and are estimated concurrently with the gravity field parameters. In other studies, the calibration method makes use of modeled accelerometer data, and the parameters are estimated in a least squares adjustment.  Depending on the calibration process, the scale factors and biases may vary significantly. In this study, an alternative calibration method is followed using the matched filter method. This method is widely used in radar applications for scattered signal detection purposes since it maximizes the signal-to-noise ratio. The idea behind this method is that a known signal is transmitted out and the reflected signal is compared to the known transmitted signal. This allows the proposed method to be based only on the satellite measurements.  In this study, the total accelerations of the satellite derived from the GPS positions, play the role of the transmitted signal that contains both the gravitational and the non-gravitational accelerations. The penumbra transitions, which appear as jumps (offsets) of very short duration in the accelerometer measurements, are used as the known calibration pulses that need to be detected in the transmitted signal. The process of matching (focusing) the penumbra transition pulse on the GPS accelerations is presented step by step and as a result, 30 daily scale factors are calculated for both missions during different periods of solar activity. The biases of the instrument are calculated daily using a second order polynomial fit. The scale factor and the biases appear to be correlated with the β’ angle variations (the angle that indicates when the satellite is in a full sun orbit). The scale factors of the cross-track component in both missions show the largest variations, since the y-axis of the accelerometer is the least sensitive, while the scale factors in the x-axis show the largest sensitivity due to thermal variations in the atmosphere . The performance of the calibration parameters during high and low solar activity is examined and evaluated.  
Study on the structure and stability characteristics of typical black soil aggregates in Northeast China based on Le Bissonnais method
Authors: Liu Huazheng , Jia Yanfeng
Published: February 2023

Abstract :[Background] The black soil area in northeast China is an important grain production base in China, and soil erosion is serious. Soil aggregate stability has a profound influence on soil erosion process. The purpose of this study was to clarify the fragmentation characteristics of surface and bottom soil aggregates in sloping farmland under different damage mechanisms, and to evaluate the stability characteristics of aggregates under different damage mechanisms, so as to provide theoretical basis for the prevention and control of soil erosion in sloping farmland in rainy season. [Methods] The typical long straight sloping farmland in northeast Black soil region was selected as the study area. Samples were taken every 30 m along the longitudinal section of the slope length, with a sampling depth of 30 cm and a sampling length of 1020 m. The particle size distribution and stability parameters of soil aggregates were determined by Le Bissonnais (LB) method (including fast wetting (FW), slow wetting (SW) and runoff disturbance (WS) treatments. [Results] 1) Under the three treatments of LB method, FW treatment (rainstorm) had the largest damage to soil aggregate structure, SW treatment (light rain) had the least damage to soil aggregate structure, and WS treatment (disturbance) was in the middle. On the whole, the aggregate stability showed MWDSW>MWDWS>MWDFW. 2) Analysis of soil aggregates in the topsoil (0-10 cm) showed that SW treatment (light rain) caused the soil aggregates to break into aggregates of >0.2 mm. WS treatment (disturbance) caused the fragmentation of soil aggregates mainly concentrated in 2-0.2 mm grain size, indicating that the >2 mm grain size aggregates were mainly destroyed by raindrop splashing, which made them split into microaggregates. After FW treatment (rainstorm), the aggregates were broken in <1 mm size, which provided abundant loose aggregates for raindrop splash erosion and runoff erosion process, and became the main source of erosion materials in soil erosion process. 3) The aggregate fragmentation of surface layer (0-30 cm) was more sensitive to 0-10 cm soil layer after light rain. The aggregate fragmentation effect under rainstorm and irrigation was more obvious in 0-20 cm soil layer. The effects of raindrop splashing and runoff disturbance on aggregate fragmentation in 0-30 cm soil layer are similar. MWD0-10cm < MWD10-20cm < MWD20-30cm in different soil layers under the three failure mechanisms. 4) In the three treatments of LB method, 1 mm grain size was taken as the critical, and 1 mm grain size was used as the index to distinguish soil stability. Soil aggregate size >1 mm had a strong resistance to soil dissipation, clay expansion and mechanical oscillation. This result could characterize the factors affecting soil stability structure.
A first look at the multivariate extreme dust outbreak over Northern Hemisphere midlatitudes
Authors: Xi Xin
Published: February 2023

Wind-driven dust emission from dry, exposed land surfaces plays an important role in the climate system, and also contributes to severe weather and public health hazards around the world. In the past several years, the Northern Hemisphere midlatitude region was stuck by several extreme dust storms with severe socioeconomic and environment consequences within and beyond the dryland source areas. For instance, the 26-27 May 2018 salt storm from the dried-up Aral Sea was considered a first-of-its-kind ecological catastrophe over Central Asia. In March 2021, northern China was hit by the worst sand storm in a decade. Later in November, Uzbekistan recorded the worst dust storm through the country’s meteorological record. Currently, significant knowledge and methodological gaps exist in characterizing the multivariate compound dust events. This study is a first attempt to develop a multivariate approach and ground-based climatology to improve our knowledge of the historical variations, spatial distributions, and governing factors of extreme dust outbreaks over the drylands of Central and East Asia. Detailed case studies will also be conducted to elucidate the role of tropic Pacific and Arctic warming and Rossby wave activities in triggering recent extreme dust events.
Factors influencing source apportionment accuracy using sediment fingerprinting: observations from New Zealand
Authors: Vale Simon , Smith Hugh
Published: February 2023

Sediment source fingerprinting is a technique for determining proportional contributions from different catchment sources to sediments in downstream receiving environments. The technique involves a) selecting tracers that discriminate sources based on their biogeochemical or isotopic properties and b) applying statistical mixing models to quantitatively determine source contributions. Tracer suitability varies depending on the characteristics of the study catchment and the source property or erosion processes being targeted and can include geochemical, fallout radionuclides (FRNs), or compound specific stable isotopes (CSSIs). For instance, the spatial variation in soil geochemical properties is largely determined by underlying geological and pedogenic processes, whereas CSSIs utilise δ13C isotopic properties of fatty acid biomarkers that bind to soils and vary based on plant communities associated with each land cover.While the environmental basis for sediment fingerprinting is increasingly understood, methodological challenges continue to present limitations that may hinder wider catchment applications. Here, we draw from recent research in New Zealand to highlight some of the challenges to source apportionment accuracy using numerical mixture testing and catchment studies to represent a range of tracers and sources. Tracers include bulk geochemistry, fallout radionuclides (FRNs), and compound specific stable isotopes (CSSIs) and sources are defined by parent material, erosion processes, and land cover. We focus on the influence of source dominance and source discrimination by different tracer types on source apportionment accuracy, as well as uncertainties introduced from post-unmixing transformations associated with CSSIs.  
Channeling, clogging and permeability oscillations: different macroscopic regimes in mineral replacement
Authors: Szymczak Piotr , Budek Agnieszka
Published: February 2023

We consider a porous medium infiltrated by a reactive fluid which triggers coupled dissolution/precipitation reactions at pore surfaces. To study these processes, we model the porous medium as a system of interconnected pipes with the diameter of each segment increasing in proportion to the local reactant consumption. Moreover, the topology of the network is allowed to change dynamically during the simulation: as the diameters of the eroding pores become comparable with the interpore distances, the pores are joined together thus changing the interconnections within the network. With this model, we investigate different growth regimes in an evolving porous medium, allowing for both erosion and precipitation of the dissolved material.The interplay of flow, transport and reaction in such a system can give rise to a variety of patterns: from spontaneous channeling to nearly homogeneous transformation of the entire rock matrix into the product phase. Interestingly, even if the product phase has a larger molar volume than the parent phase, clogging in such a system can be avoided, due to the interplay of dissolution and precipitation resulting in the continuous creation of new flow paths. These results can be relevant for the analysis of carbonation reactions, in which an important goal is to avoid clogging of the pore space that can lead to permeability reduction and the overall slowdown of the process.