bluuebunny/crossref_metadata_2025 huggingface dataset:
On the needs to evaluate power grid models’ hydropower scheduling with a river operations model
Authors: Voisin Nathalie , Magee Tim , Turner Sean , Clement Mitch , Oikonomou Konstantinos , Zagona Edith
Published: March 2022

Production Cost Models (PCMs) simulate the economic dispatch of generators across a large power grid and are used widely by planners to study the reliability of electricity supply. As energy systems transition away from the thermoelectric technologies that have traditionally balanced electricity supply and demand, hydropower and its representation in PCMs is of increasing importance for storage and ramping capabilities. A limitation of PCMs applied to continental power grids with diverse generation portfolios is that hydropower generation is simulated without full consideration of complex river dynamics, leading to possible misrepresentation of grid flexibility and performance.

Using a detailed hydropower model, we evaluate whether the hourly hydropower schedule from a PCM with simplified monthly parameterization can be attained when accounting for realistic river dynamics, such as spill requirements and general water movement through a cascading reservoir system. We perform this hydropower generation test for the “Big 10” hydropower system on the Columbia River (part of the Western Interconnect of the United States), revealing 9% overestimation of available hydropower generation in a PCM solution in an average hydrologic year.

We reflect on the sources of differences with implications onto long term planning practices expected to address uncertainties associated with energy transitions, climate change, environmental regulation and competing water uses.
PESTICIDE REMOBILIZATION in VEGETATIVE FILTER STRIPS USING MESOSCALE MULTI-EVENT EXPERIMENTATION
Authors: Howe John , Munoz-Carpena Rafael
Published: March 2022

VFSMOD, a numerical storm-based vegetative filter strip (VFS) design model, calculates pesticide mitigation from runoff through VFS in regulatory long-term ecotoxicological exposure assessments. After each storm, the model calculates degradation in the hiatus period and currently adopts a risk-conservative approach of full remobilization of surface pesticide residues during following storms. For highly-sorbed chemicals, although risk-conservative, this assumption has been shown to be unrealistic and a revised mechanistic modeling approach that produces accurate estimates across a wide range of chemicals is sought.  To test the ability of the revised modeling approach to predict VFS efficacy accurately over time, a mesoscale experiment was designed using triplicated 1.2Lx0.35Wx0.5D m soil boxes with VFS planted on the surface.  The device was instrumented to quantify how different types of pesticides are remobilized from the VFS surface over consecutive rainfall events with a hiatus in between. A rainfall simulator provides uniformly distributed precipitation input at 5-year storm intensity and a lateral inflow spreader provides runoff entering the upper side of the VFS. A chemical tracer is added to the pesticide and sediment inflow suspension and tracked through the system using a longitudinal grid of 12 soil moisture and electrical conductivity sensors, and 4 automatic flow meters at 3 drainage and 1 surface runoff outlets per box. Infiltration and runoff are quantified to close the mass balance.  The use of advanced instrumentation is vital to achieve data with high spaciotemporal resolution for analysis. Due to the complex nature of the VFS environment, system subcomponents are sequentially tested for water traceability. Before the addition of pesticides, the system was tested with water and tracer. Preliminary mass balance results will ensure all water is traceable through the system, which will be essential during later experimentation with pesticides.
Hydrology Research Articles Are Becoming More Interdisciplinary
Authors: Rahman Mashrekur , Frame Jonathan , Lin Jimmy , Nearing Grey
Published: March 2022

We used Natural Language Processing (NLP) to assess topic diversity in the abstracts of all research articles (75,000) from eighteen water science and hydrology journals published between 1991 and 2019 -- these are all water science journals with an SCI h-index > 0.9. We found that individual water science and hydrology research articles are becoming increasingly interdisciplinary in the sense that, on average, the number of sub-topics that are represented in individual articles is increasing. This is true even though the body of water science and hydrology literature as a whole is not becoming more topically diverse. These findings suggest that the National Research Council's (1991) recommendation to increase multidisciplinarity of hydrological research has been followed in the sense that individual researchers are working to make their work more interdisciplinary. Topics with the largest increases in popularity were ‘Forecasting’ and ‘Climate Change Impacts’, and topics with the largest decreases in popularity were ‘Hydraulics’, ‘Solute Transport’, and ‘Aquifers and Abstraction’. Out of the eighteen journals that we tested, Hydrological Processes, Journal of Hydrology, and Water Resources Research are the three most topically diverse journals in the discipline. We also identified topics that are becoming increasingly isolated, and could potentially benefit from integrating more with the wider hydrology discipline.
Using a Pangeo platform on Azure to tackle global environmental challenges 
Authors: Lam Timothy , Arribas Alberto , Shaddick Gavin , McCaie Theo , Catto Jennifer
Published: March 2022

The Pangeo project enables interactive, reproducible and scalable environmental research to be carried out using an integrated data-computational platform. Here we demonstrate a few examples that utilise a Pangeo platform on Microsoft Azure supported by the Met Office where global environmental challenges are explored and tackled collaboratively. They include: (1) Analysing and quantifying drivers of low rainfall anomalies during boreal summer in Indonesian Borneo using causal inference and causal network to identify key teleconnections, and their possible changes under a warming climate, which will contribute to seasonal forecasting efforts to strengthen prevention and control of drought and fire multihazards over peatlands in the study region; (2) Quantifying and communicating uncertainty in volcanic ash forecasts; and (3) Exploring the cascading effects that follow the degradation and recovery of Caribbean coral reefs.
Causal Diagnostics for Observations - Experiments with the L63 system
Authors: Chakraborty Nachiketa , Amezcua Javier
Published: March 2022

Study of cause and effect relationships – causality - is central to identifying mechanisms that cause the phenomena we observe. And in non-linear, dynamical systems, we wish to understand these mechanisms unfolding over time. In areas within physical sciences like geosciences, astrophysics, etc. there are numerous competing causes that drive the system in complicated ways that are hard to disentangle. Hence, it is important to demonstrate how causal attribution works with relatively simpler systems where we have a physical intuition. Furthermore, in earth and atmospheric sciences or meteorology, we have a plethora of observations that are used in both understanding the underlying science beneath the phenomena as well as forecasting. However in order to do this, optimally combining the models (theoretical/numerical) with the observations through data assimilation is a challenging, computationally intensive task. Therefore, understanding the impact of observations and the required cadence is very useful. Here, we present experiments in causal inference and attribution with the Lorenz 63 system – a system studied for a long time. We first test the causal relations between the variables characterising the model. And then we simulate observations using perturbed versions of the model to test the impact of the cadence of observations of each combination of the 3 variables.
First measurements of fine-vertical-scale wave impacts on the tropical lower stratosphere
Authors: Bramberger Martina , Alexander M. Joan , Davis Sean M. , Podglajen Aurelien , Hertzog Albert , Kalnajs Lars , Deshler Terry , Goetz J. Douglas , Khaykin Sergey
Published: March 2022

Atmospheric waves in the tropical tropopause layer are recognized as a significant influence on processes that impact global climate. For example, waves drive the quasi-biennial oscillation (QBO) in equatorial stratospheric winds and modulate occurrences of cirrus clouds. However, the QBO in the lower stratosphere and thin cirrus have continued to elude accurate simulation in state-of-the-art climate models and seasonal forecast systems. We use first-of-their-kind profile measurements deployed beneath a long-duration balloon to provide new insights into impacts of fine-scale waves on equatorial cirrus clouds and the QBO just above the tropopause. Analysis of these balloon-borne measurements reveals previously uncharacterized fine-vertical-scale waves (<1km) with large horizontal extent (>1000km) and multiday periods. These waves affect cirrus clouds and QBO winds in ways that could explain current climate model shortcomings in representing these stratospheric influences on climate. Accurately simulating these fine-vertical-scale processes thus has the potential to improve sub-seasonal to near-term climate prediction.
Applications of Satellite Altimetry Observations
Authors: Srinivasan Margaret , Tsontos Vardis , Hossain Faisal
Published: March 2022

Thirty years of altimetry satellite observations have provided important information that enables research discoveries and aids in the development of user-driven applications. National and international space and operational agencies have committed substantial resources to developing and continuing observations of the ocean and large water bodies (lakes, reservoirs, large rivers) through collaboration in these missions. Over the next few years, NASA and other agencies will launch new research missions with technologies that will extend, expand, and evolve observations of ocean, coastal and inland waters. New discoveries and advances in societally relevant applications can be leveraged with increased spatial, temporal and spectral resolutions. We will highlight the use of data from these existing and planned missions for operational and applied user-driven applications and their societal benefits. Topics may include the use of existing, retrospective, and expected time series that contribute to applications such as marine operations, marine biology and biodiversity, coastal studies, hurricanes and other hazards, as well as hydrologic assessments, water resources management, and other surface water applications.
Lessons Learned: Implementing Managed RealignmentAnd Restoring Tidal Wetlands In Nova Scotia
Authors: Graham Jennie , van Proosdij Danika , Bowron Tony , Lundholm Jeremy
Published: March 2022

This presentation will examine how monitoring of past tidal wetland restorations has been used to inform design, implementation, and adaptive management of current projects in Nova Scotia, Canada.  Over the last 15 years, CBWES, Saint Mary’s University and the Province have restored close to 400 ha of tidal wetland habitat through culvert replacement, impoundment breaches and dyke realignment.  Standardized pre and 5-year post restoration monitoring plans have provided valuable lessons that are being applied to upcoming projects. These include modified installation of standard equipment such as RSETs to fit the unique conditions in NS, determining best practices regionally to channel network design and implementation in a macro-tidal environment, and how and when to employ adaptive management techniques. Finally, this presentation will consider the importance of effective communication in tidal wetland restoration in a multi-disciplinary and multi-jurisdictional environment.
Laboratory study to better understand hydraulic fracturing-induced seismicity and fracture propagation
Authors: Li Lei , Xie Jingyu , Tan Jingqiang , Shu Biao , Zhou Wen , Pan Xinpeng , Liu Jianxin
Published: March 2022

Unconventional geo-energy resources, such as shale gas and geothermal energy, are supposed to play an essential role in energy transition and carbon neutrality. Currently, hydraulic fracturing is still the dominant stimulation strategy to obtain economic production. Hydraulic fracture (HF) propagation behavior is significant to characterize the reservoir and evaluate the stimulation efficiency. Interpretation of the reservoir fracture growth is challenging due to the coupled effects of geological and engineering conditions. Under controlled conditions, laboratory study can better reveal the physical mechanisms of induced seismicity and HF propagation. We conducted two separate laboratory studies using shale and granite samples, respectively. For the uniaxial loading experiments of shale samples, multifractal method, time-frequency analysis, event location, and micro-CT scanning techniques were utilized to quantitatively characterize acoustic emission events and HFs. The fracturing process could be divided into three stages as the initial stage, the quite stage, and the fracturing stage. For the true triaxial loading experiments of granite samples, the influence of multiple structural planes (SPs) on the HF propagations was studied. The HF geometry displayed four basic patterns when encountering SPs, namely, propagation along the SPs, branching, capture, penetration/non-dilation. The cementing strength and mechanical properties of the SPs influence the HF behaviors significantly. Laboratory fracturing experiments can help provide theoretical and technical guidance for field hydraulic fracturing operations in shale reservoirs and enhanced geothermal systems. Future work will involve a more systematic analysis and comparison between HF propagation behaviors for different rocks under different geological and engineering conditions.
Shoreline change and storm forcing over the last two centuries in Dundrum Bay (Northern Ireland)
Authors: Grottoli Edoardo , Biausque Melanie , Jackson Derek , Cooper Andrew
Published: March 2022

Shoreline change and storm forcing are analysed for Murlough and Ballykinler beaches (Dundrum Bay, Northern Ireland) over the last two centuries. The two beaches are divided by a pronounced ebb tidal delta and an inlet channel connecting the outer Dundrum Bay with the inner bay. Twenty-four shorelines were digitised from multiple datasets (historical maps, aerial photos, orthophotos and GNSS surveys) covering from 1833 to 2020. The seaward dune vegetation line was selected as shoreline proxy. Shoreline uncertainty was assessed considering various errors inherent from each dataset from which the shoreline was digitised. A coeval storm dataset since 1825 and an extreme water levels (EWLs) dataset from 1901 to 2020 were built using hindcasted wave parameters, historical news and recorded water levels from two local tide gauges. Volume changes from 1963 to 2014 were calculated applying the Structure-from-Motion technique to historical aerial photos.

Over the entire study period, Murlough displayed a retreat trend along 90% of its shoreline, whereas Ballykinler experienced an accretional pattern along 86% of its length. Three foredune blowouts characterise Murlough beach with an increasing landward extent toward the inlet. Murlough’s blowouts were reactivated and underwent recovery multiple times throughout the analysed period. In Ballykinler, a large blowout generated in 1951 is now replaced by an advancement trend particularly over the last 20 years.

On both sites, the largest blowouts were evident in 1951 and a clear erosive signature was also left by the 2013-2014 winter storm season. Three consecutive EWLs were recorded in 1946 and at the start of 2014, indicating that prolonged EWL events combined with a cluster of storms, were a significant driver of episodic coastal retreat phases. Volume analyses from 1963 to 2014 confirm that the sand moves from Murlough toward Ballykinler whose foredune gained more than twice the sand volume lost from the foredune in Murlough. Comparisons of recent and historical beach profiles of Ballykinler confirmed a beach growth of about one meter in elevation since 1963 throughout the entire beach profile. The role of the ebb tidal delta linked to wave energy dissipation and wave direction requires further investigation to explain the entire sediment dynamics of the study site.
Calibration of wind speed ensemble forecasts for power generation
Authors: Baran Sándor , Baran Ágnes
Published: March 2022

In 2020, 36.6 % of the total electricity demand of the world was covered by renewable sources, whereas in the EU (UK included) this share reached 49.3 %. A substantial part of green energy is produced by wind farms, where accurate short range power predictions are required for successful integration of wind energy into the electrical grid. Accurate predictions of the produced electricity require accurate forecasts of the corresponding weather quantity, where the state-of-the-art method is the probabilistic approach based on ensemble forecasts. However, ensemble forecasts are often uncalibrated and might also be biased, thus require some form of post-processing to improve their predictive performance.

To calibrate (hub height) wind speed ensemble forecasts we propose a novel flexible machine learning approach, which results either in a truncated normal or a log-normal predictive distribution (Baran and Baran, 2021). In a case study based on 100m wind speed forecasts of the operational AROME-EPS of the Hungarian Meteorological Service, the forecast skill of this method is compared with the predictive performance of three different ensemble model output statistics approaches and the raw ensemble predictions. We show that compared with the raw ensemble, post-processing always improves the calibration of probabilistic and accuracy of point forecasts, and from the five competing methods the novel machine learning based approaches result in the best overall performance. 

Reference

Baran, S., Baran, Á., Calibration of wind speed ensemble forecasts for power generation. Idöjárás 125 (2021), 609-624.
Integrating topographic knowledge into deep learning for the void-filling of digital elevation models
Authors: Li Sijin , Xiong Liyang , Tang Guoan
Published: March 2022

Digital elevation models (DEMs) contain some of the most important data for providing terrain information and supporting environmental analyses. However, the applications of DEMs are significantly limited by data voids, which are commonly found in regions with rugged terrain. We propose a novel deep learning-based strategy called a topographic knowledge-constrained conditional generative adversarial network (TKCGAN) to fill data voids in DEMs. Shuttle Radar Topography Mission (SRTM) data with spatial resolutions of 3 and 1 arc-seconds are used in experiments to demonstrate the applicability of the TKCGAN. Qualitative topographic knowledge of valleys and ridges is transformed into new loss functions that can be applied in deep learning-based algorithms and constrain the training process. The results show that the TKCGAN outperforms other common methods in filling voids and improves the elevation and surface slope accuracy of the reconstruction results. The performance of TKCGAN is stable in the test areas and reduces the error in the regions with medium and high surface slopes. Furthermore, the analysis of profiles indicates that the TKCGAN achieves better performance according to a visual inspection and quantitative comparison. In addition, the proposed strategy can be applied to DEMs with different resolutions. This work is an endeavour to transform perceptive topographic knowledge into computer-processable rules and benefits future research related to terrain reconstruction and modelling.
Chemistry breaks rocks and self-accelerate fluid flow in the lithosphere: Experimental insights from MgO–H2O system
Authors: Uno Masaoki , Okamoto Atsushi , Tsuchiya Noriyoshi
Published: March 2022

Hydration and carbonation reactions within the Earth cause an increase in solid volume by up to several tens of vol%, which can induce stress and rock fracture [e.g., 1]. Observations of naturally hydrated and carbonated peridotite and troctolite suggest that permeability and fluid flow are enhanced by reaction-induced fracturing [e.g., 2, 3]. However, permeability enhancement during solid-volume-increasing reactions has not been achieved in the laboratory, and the mechanisms of reaction-accelerated fluid flow remain largely unknown. Here, we present the first report of significant permeability enhancement by volume-increasing reactions under confining pressure [4]. The hydromechanical behaviour of hydration of sintered periclase [MgO + H2O → Mg(OH)2] depends mainly on the initial pore-fluid connectivity. Permeability increased by three orders of magnitude for low-connectivity samples, whereas it decreased by two orders of magnitude for high-connectivity samples. Permeability enhancement was caused by hierarchical fracturing of the reacting materials, whereas decrease was associated with homogeneous pore-clogging by the reaction products. These behaviours suggest the fluid flow rate, relative to reaction rate, is the main control on hydromechanical evolution during volume-increasing reactions. We suggest that an extremely high reaction rate and low pore-fluid connectivity lead to local stress perturbations, and are essential for reaction-induced fracturing and accelerated fluid flow during hydration/carbonation.

 

[References]

1: Kelemen and Hirth, 2012. EPSL 345–348, 81–89.

2: Jamtveit, Malthe-Sørenssen, Kostenko, 2008. EPSL 267, 620–627.

3: Yoshida, Okamoto et al., 2020 JGR 125, e2020JB020268.

4: Uno, Okamoto, Tsuchiya et al., 2022. PNAS 119, 3, e2110776118.
Variability of the Weddell Gyre in a global high-resolution numerical model
Authors: Neme Julia , England Matthew , Hogg Andrew McC
Published: March 2022

The Weddell Gyre, located in the Weddell Sea is one of the southernmost open ocean reaches in the world and largest feature of the ocean circulation south of the Antarctic Circumpolar Current. It is adjacent to a major site of bottom water production in the southwestern Weddell Sea and participates in poleward heat transport via its cyclonic circulation that brings relatively warm waters south towards the Antarctic continent. The region is covered by sea ice through most of the year, which has historically prevented long, continuous observational efforts, both in situ and remote. As a result, ocean circulation models offer perhaps the best means of estimating the Weddell Gyre's variability. Using a coupled ocean/sea ice high-resolution global model, ACCESS-OM2 at 0.1∘ horizontal resolution, we assess the variability of the Weddell Gyre on seasonal - multi-decadal timescales and explore possible drivers of this variability. The simulations suggest that the gyre is exhibits large variability in its circulation that is not captured by summer-biased or short-term observations. Anomalous strong and weak periods of the gyre's circulation are linked to changes in sea ice concentration and other oceanic features of the region. We further explore the link to possible driving mechanisms, including surface stress forcing and surface buoyancy fluxes.
Water Isotopic Signature of Surface Snow Metamorphism in Antarctica
Authors: Casado Mathieu , Zuhr Alexandra , Landais Amaëlle , Picard Ghislain , Arnaud Laurent , Dreossi Giuliano , Stenni Barbara , Prié Frederic
Published: March 2022

Water isotope ratios of ice cores are a key source of information on past temperatures. Through fractionation within the hydrological cycle, temperature is imprinted in the water isotopic composition of snowfalls. However, this signal of climatic interest is modified after deposition when snow remains at the surface exposed to the atmosphere. Comparing time series of surface snow isotopic composition at Dome C with satellite observations of surface snow metamorphism, we found that long summer periods without precipitation favor surface snow metamorphism altering the surface snow isotopic  composition. Using excess parameters (combining dD, d17O, and d18O fractions) allow the identification of this alteration caused by sublimation and condensation of surface hoar. The combined measurement of all three isotopic compositions could help identifying ice core sections influenced by snow metamorphism in sites with very low snow accumulation.
Chemical Analysis of Trace Elements at the Nanoscale in Samples Recovered from Laser-Heated Diamond Anvil Cell Experiments
Authors: Blanchard Ingrid , Petitgirard Sylvain , Laurenz Vera , Miyajima Nobuyoshi , Wilke Max , Rubie Dave , Lobanov Sergey S. , Hennet Louis , Morgenroth Wolfgang , Tucoulou Rémi , Bonino Valentina , Zhao Xuchao , Franchi Ian
Published: March 2022

High pressure and high temperature experiments performed with laser-heated diamond anvil cells (LH-DAC) are being extensively used in geosciences in order to study matter at conditions prevailing in planetary interiors. Due to the size of the apparatus itself, the samples that are produced are extremely small, on the order of few tens of micrometers. There are several ways to analyze the samples and extract physical, chemical or structural information, using either in situ or ex situ methods. Here, we will compare two nanoprobe techniques, namely nano X-ray fluorescence (nano-XRF) and Nanoscale secondary ion mass spectrometry (NanoSIMS), that can be used to analyze samples synthetized in LH-DAC and recovered using Focused Ion Beam. The two techniques are very different in various aspects, the most important one being that nano-XRF is a deeply penetrative but nondestructive method, whereas NanoSIMS is a surface sensitive and destructive method. The second major difference between the two techniques is that NanoSIMS can probe isotopes, whereas nano-XRF cannot. With both, it is possible to obtain the spatial distribution of chemical elements in the samples.

We used these two nanoprobes to retrieve elemental concentrations and ratios of dilute moderately and highly siderophile elements (few tens of ppm) in quenched experimental melts relevant for the formation of the core of the Earth. We will show those results and discuss the importance of proper calibration for the acquisition of quantifiable results. We have also performed metal–silicate partitioning experiments in which tungsten and molybdenum were incorporated. Those experiments are especially relevant to understand the core–mantle differentiation of the Earth, about 4.5 billion years ago. We will first present and compare metal–silicate partition coefficient obtained by both nano-XRF and NanoSIMS, and second also with results obtained independently by electron microprobe.
Hust Index applied in the soil resistance measurements based on a harrow discs sensors
Authors: López-Cuervo Serafin , Lamas López Francisco , Lazcano Lasa Miren Bakarne , Saa-Requejo Antonio , Martín-Sotoca Juan J. , Pérez Martín Enrique , López Herrera Juan , Caso Diaz-Aguilar Jose Gabriel , Tarquis Ana M.
Published: March 2022

The mechanical conditions of the soil is essential for the planning and implementation of agricultural tillage. Determining the variability of the soil by sensors helps to optimize the intensity of the use of tillage components, control their wear and improve the energy consumption of the operation. This work presents the development of hardness and plasticity parameters by means of sensors implanted in tillage components such as harrow discs. The vibration measurement by an electronic sensor integrated in a harrow disc is packaged and sent to a control node where it is transformed to the frequency space and parameterized through the power spectral density (PSD). The energy analysis makes it possible to establish the variability of the terrain in degrees of hardness and plasticity; and thereby determine differential harrow management or plot mapping for decision making.

Lately, a Detrended Flucutation Analysis (DFA) of Hurst Index on these series were applied for first time. The presistence and antipersistant character of the Hurst index can help to identify the  hardeness of the plot analysed. Results are showed comparing different soil texture and soil humidity scenarios.
Parameter sensitivity of plant productivity in a plant hydraulics-enabled DGVM
Authors: Eckes-Shephard Annemarie , Papastefanou Phillip , Rammig Anja , Pugh Thomas A. M.
Published: March 2022

Limited process-representation of plant hydraulics in Dynamic Global Vegetation Models (DGVMs) impacts our ability to improve our understanding of the effect of plant water availability on vegetation dynamics and vegetation carbon content.  More detailed plant hydraulics have so far been only introduced in a few DGVMs. Here, we apply the new hydraulics version of the DGVM LPJ-GUESS to explore the impact of hydraulic functional traits on plant productivity and succession dynamics. We perform a sensitivity analysis on hydraulic and shade-tolerance traits across different Plant Functional Types (PFTs).

Our study is performed at multiple sites along a water-availability gradient in a temperate environment. We put special focus on exploring the simulated interplay between shade-tolerant and intolerant broadleaf summergreen PFTs and discuss the most sensitive parameters and the implications of constraining them for future climate projections.
 Simulating the impacts of present-day and future agricultural emissions on crop yield and human health in China
Authors: Graham Ailish M , Chipperfield Martyn , Emberson Lisa , O’Neill Connie , Bland Sam , Malley Chris , Jew Eleanor , Hicks Kevin , Wooster Martin , Liu Zixia , Oliver Catherine , Panda Pritha , Hicks Nathan
Published: March 2022

Globally, agriculture is a key source of both CO2 and non-CO2 greenhouse gas (GHG) emissions. In China 41% of total GHG emissions (~3.5% of global GHG emissions) and 50% of non-CO2 GHG emissions are from agriculture. The large contribution of agriculture to overall emissions in China stems from the introduction of the 1987 Reform and Opening policy. The policy encouraged farm labourers to move to cities for better paid jobs. As a result agriculture became more reliant on fertiliser and machinery use, increasing agricultural emissions. Production and consumption, which are closely linked to emissions, are predicted to continue to increase according to the 10-year outlook. However, China has pledged to reach peak emissions by 2030.

 

We simulate the impact of recent-past and future agricultural emissions on air pollutant concentrations using the WRF-Chem model. The Stockholm Environment Institute demand based agricultural emissions model, driven by 10 year outlook data, is used to provide Chinese agricultural emissions for 2017 and 2030. Three future scenarios are explored for 2030: 1) baseline, 2) baseline + on-farm measures 3) baseline + on-farm + demand side measures. We quantify the contribution of China’s current targets to 2030 air pollutant concentrations under the outlook projections (baseline). We also explore the additional pollutant reductions that could be achieved from on-farm (animal feed composition, rice water regimes, agricultural burning, proportion of synthetic fertiliser application etc.) and demand-based (population diet, food waste etc.) emissions reductions. Stakeholder engagement and a digital survey are used to inform on-farm emission reduction options and possible barriers to adoption. The impact of pollutant concentrations is also quantified on crop yields and human health using the Deposition of Ozone for Stomatal Exchange (DO3SE) model and disease-specific exposure-response functions, respectively. 
crestr An R package to perform probabilistic climate reconstructions using fossil proxies
Authors: Chevalier Manuel
Published: March 2022

Statistical climate reconstruction techniques are fundamental tools to study past climate variability from fossil proxy data. In particular, the methods based on probability density functions (or PDFs) have the potential to be used in various environments and with different climate proxies because they rely on elementary calibration data (i.e. modern geolocalised presence data). However, the access and curation of these calibration data, as well as the complexity of interpreting probabilistic results, often limit their use in palaeoclimatological studies. I introduce a new R package (crestr) to apply the CREST method (Climate REconstruction SofTware) on diverse palaeoecological datasets and address these problems. crestr includes a globally curated calibration dataset for six common climate proxies (i.e. plants, beetles, chironomids, rodents, foraminifera, and dinoflagellate cysts) associated with an extensive range of climate variables that enables its use in most terrestrial and marine environments. Private data collections can also be used instead of, or in combination with, the provided calibration dataset. The package includes a suite of graphical diagnostic tools to represent the data at each step of the reconstruction process and provide insights into the effect of the different modelling assumptions and external factors that underlie a reconstruction. With this R package, the CREST method can now be used in a scriptable environment, thus simplifying its use and integration in existing workflows. It is hoped that crestr will contribute to producing the much-needed quantified records from the many regions where climate reconstructions are currently lacking, despite the availability of suitable fossil records. The use of the package will be illustrated with a recent application to produce a 790,000 year long mean annual temperature reconstruction based on a pollen record from southeastern Africa.
Orientation of swimmers in turbulent flows
Authors: De Lillo Filippo , Borgnino Matteo , Boffetta Guido , Gustafsson Kristian , Mehlig Bernhard , Cencini Massimo
Published: March 2022

Many phytoplankters are able to swim, and are thus not passively transported by the flow. Although usually weak, ocean turbulence can affect the motion of one-celled organisms in nontrivial ways. It is known that an ellipsoidal body can be rotated by the fluid gradients, depending on its aspect ratio.  On the other hand, directed swimming (e.g. following chemical or physiscal cues, in any form of taxis) can play an important role in determining the fitness of an individual, whether for finding food, light or escaping from predators.

By means of theoretical and numerical investigation [1,2], we show how a microswimmer's orientation can be influenced by different scales of the flow and in what condition relevant correlation with the orientation of the flow can be expected.   

 

[1] Alignment of nonspherical active particles in chaotic flows M Borgnino, K Gustavsson, F De Lillo, G Boffetta, M Cencini, B Mehlig, Physical review letters 123 (13), 138003

[2] M Borgnino, K Gustavsson, F De Lillo, G Boffetta, M Cencini (2021) in preparation.
Glacial drought buffering through the 21st century
Authors: Ultee Lizz , Coats Sloan , Mackay Jonathan
Published: March 2022

Global climate model projections suggest that 21st century climate change will bring significant drying in the terrestrial midlatitudes. Recent glacier modeling suggests that runoff from glaciers will continue to provide substantial freshwater in many drainage basins, though the supply will generally diminish throughout the century. In the absence of dynamic glacier ice within global climate models (GCMs), a comprehensive picture of future drought conditions in glaciated regions has been elusive. We evaluate glacial buffering of droughts in the Standardized Precipitation-Evapotranspiration Index (SPEI), which we calculate by combining CMIP5 climate model output with glacial runoff projections from GloGEM.

We find that accounting for glacial runoff tends to increase multi-model ensemble mean SPEI (wetter baseline) and reduce drought frequency and severity, even in basins with glacier cover of <2% by area.  We also find that the strength and future trend of glacial drought buffering depends on basin aridity index and glacial cover, and does not depend on other characteristics such as total basin area or latitude.  Glacial drought buffering persists even as glacial runoff is projected to decline through the 21st century.
Photochemical degradation of dimethylmercury in natural waters             
Authors: West Johannes , Gindorf Sonja , Jonsson Sofi
Published: March 2022

Photochemical degradation of dimethylmercury (DMHg) could constitute an important source of monomethylmercury (MMHg) in surface waters, thus impacting Hg bioaccumulation and exposure risks. Despite this, few have studied this process, and no consensus has been reached on whether DMHg photodegradation occurs in nature. We used isotope labeling techniques to study DMHg and MMHg photodegradation in natural waters when exposed to artificial UV light. Our results confirm that DMHg degrades at rates comparable to those of MMHg for a variety of natural waters. We corroborated these findings in outdoor experiments, where samples containing DMHg and MMHg were exposed to natural sunlight. Comparison of the rates of photodecomposition for DMHg and MMHg in various water types imply differences in underlying reaction mechanisms for the species. To learn more about the factors controlling DMHg photodecomposition, we performed additional experiments where the effects of factors such as DOC, Cl- and O2 concentrations on DMHg and MMHg photodegradation rates were compared. Our findings indicate that the DMHg à MMHg flux through DMHg photodecomposition could represent a significant vector for MMHg production in surface oceans.
Optimization of Agricultural Management for Soil Carbon Sequestration UsingDeep Reinforcement Learning and Large-Scale Simulations
Authors: Kalantari Zahra
Published: March 2022

Soil carbon sequestration in croplands has tremendous potential to help mitigate climate change; however, it is challenging to develop the optimal management practices for maximization of the sequestered carbon as well as the crop yield. We aim to develop an intelligent agricultural management system using deep reinforcement learning (RL) and large-scale soil and crop simulations. To achieve this, we build a simulator to model and simulate the complex soil-water-plant-atmosphere interaction, which will run on high-performance computing platforms. Massive simulations using such platforms allow the evaluation of the effects of various management practices under different weather and soil conditions in a timely and cost effective manner. By formulating the management decision as an RL problem, we can leverage the state-of-the-art algorithms to train management policies through extensive interactions with the simulated environment. The trained policies are expected to maximize the stored organic carbon while maximizing the crop yield in the presence of uncertain weather conditions. The whole system is tested using data of soil and crops in both mid-west of the United States and the central region of Portugal. Our study has great potential for impact on climate change and food security, two of the most significant challenges currently facing humanity.
Climatology of West Antarctic Atmospheric Rivers and their Impacts on Surface Mass Balance 
Authors: Maclennan Michelle , Lenaerts Jan
Published: March 2022

Authors:

Michelle L. Maclennan, Jan T. M. Lenaerts, Christine A. Shields, Andrew O. Hoffman, Nander Wever, Megan Thompson-Munson, Erin C. Pettit, Theodore A. Scambos, and Jonathan D. Wille.

While Antarctic Ice Sheet (AIS) mass loss is dominated by accelerated ice discharge from the West Antarctic Ice Sheet (WAIS) due to ocean-induced basal melting, surface mass balance (SMB) processes return mass to the WAIS through snowfall. On Thwaites Glacier (TG) in West Antarctica, snowfall is the primary driver for SMB (125 ± 16 Gt snowfall per year), and extreme snowfall events contribute more than 60% of the total snowfall over TG ice shelf, and 30-50% of the total snowfall over grounded TG. Many of these extreme snowfall events are associated with the landfall of atmospheric rivers (ARs). ARs are long, narrow bands of warm and moist air that contribute intense precipitation and surface melting on the AIS, meaning they contribute both positively and negatively to the SMB. Here, we use an Antarctic-specific AR detection tool combined with MERRA-2 and ERA5 reanalyses to develop a climatology of AR events that made landfall over TG and the WAIS from 1980-2020, including their frequency and duration. We quantify the snowfall and surface melt attributed to AR events to determine their impacts on WAIS SMB. Using two case studies of AR events in December 1999 and February 2020, we illustrate the spatial patterns in snowfall and surface melt associated with AR landfall. We then compare the seasonal and spatial patterns in AR-attributed snowfall to the climatology of all snowfall over the WAIS. Finally, we highlight the interannual and decadal variability of West Antarctic AR events and their relationships to large-scale modes of atmospheric variability. Our results enable us to quantify the past impacts of ARs on WAIS SMB and characterize their interannual variability and trends, enabling a better assessment of future AR-driven changes in SMB.

 
Impact of wetting-drying cycles on the hydro-mechanical behaviour of vegetated soil
Authors: Anselmucci Floriana , Cheng Hongyang , Zeng Yijian , Fan Xinyan , Magnanimo Vanessa
Published: March 2022

Climate change strongly affects the hydro-mechanical properties of soil. Due to drought and heavy rains
the soil is subjected to severe hydro-mechanical loads, that, in turn, alter the microstructure of the soil.
The most affected area is the so-called vadose zone, the layer of soil situated between the ground surface and
the water table. Here the presence of vegetation has a strong impact, related to the elongation/expansion
of the root architecture and the hydro-mechanical interactions with soil. Additionally, the presence of plant
roots facilitate the evapotranspiration process from deeper soil layers.
The research presents an experimental investigation, aimed to reproduce the typical hydro-mechanical
conditions as found in the vadose zone in controlled laboratory conditions. Drying-wetting cycles are induced
in soils samples, where maize plants are free to sprout and develop as well as in reference non-vegetated
samples. The water content and distribution within the soil matrix are studied through 4D (3D+time)
in-vivo x-ray computed tomography and effects on the soil-root microstructure are quantified with 3D
image analysis. Those are correlated with above ground measurements such as fluorescence (through a
spectroradiometer) that, in turn, provides leaf water potential, and the stomatal conductance that controls
the evapotranspiration.
Using SWAT model to evaluate the plausible changes in a karst snow-fed watershed in the Moroccan High Atlas
Authors: Taia Soufiane , Erraioui Lamia , Chao Jamal , Scozzari Andrea , El Mansouri Bouabid
Published: March 2022

High Atlas is considered as one of the major reservoirs of freshwater for crop yield and hydropower production in the plains of central Morocco. Nevertheless, snowmelt and discharge in this region have been reported very vulnerable to climate variability, which threaten the sustainability and development of socio-economic activities in this region. Thus, there’s a strong need to understand the spatio-temporal variability of water cycle in addition to the impact of the changing climate on the main hydrological components.  This work focuses on the application of SWAT model in the mountainous watershed of Oued Al Abid river, which is potentially threatened by climate and anthropogenic forcings. The study is based on two main axes: (i) the implementation of SWAT to model the snowmelt discharge processes over this watershed taking into consideration the karst structure of this area, (ii) the projection of climate change has been also analyzed by forcing SWAT model using three simulations of Regional Climate Model RCA4. Results showed that SWAT model performed satisfactory to very good in reproducing discharge and reservoir inflow. According to the results, the hydrological components showed a significant variability, particularly in snowmelt, infiltration and surface runoff. Furthermore, negative variation and peak shift in the projected inflows to the dam have been demonstrated by this study.
Distinct patterns of change of organic matter in bulk soil or in earthworm casts during ageing
Authors: Quenea Katell , Nunan Naoise , Lerch Thomas , Chenu Claire , Aubry Emmanuel , Pouteau Valerie , Plessis Cedric , Leloup Julie
Published: March 2022

Earthworm activities in soil generate biogenic aggregates (casts), the mass of which can reach up to 30 - 50t/ha. The dynamics of organic matter (OM) is strongly constrained (accessibility, O2 content, etc.) within these structures and they tend to have high OM contents. As a result of their large mass and high OM contents, these aggregates can have significant effects on OM dynamics and protection over distinct time scales: (i) over the short term, earthworms increase OM mineralization through their own metabolic processes and by stimulating soil microbial activity, the so-called priming effect; (ii) over longer terms, during cast ageing, a new equilibrium may be reached, leading to the protection of the incorporated OM. However few incubation studies have been conducted for more than three months. Consequently, the net influence of earthworm’s casts on the OM dynamics is still poorly understood and remains to be determined.

Our objective was to estimate whether the incorporation of fresh OM into casts leads to its protection or to an enhanced degradation during the period of cast ageing. To do so, we compared the fate of 13C labeled fresh OM added to bulk soil to the fate of fresh OM ingested by earthworms (L. Terrestris) in mesocosms, and monitored OM mineralization during one year. The incorporation of fresh OM into casts was also determined as were the microbial communities involved in the consumption of labelled OM (via 13C-phospholipid fatty acid analysis). In addition, the OM stability was estimated as the proportion of mineral associated.

The results showed that fresh OM was largely incorporated into casts, with significant differences in the mineralization rates obtained for the OM incorporated into the soil, compared with that incorporated into the casts. This difference decreased over time, as the casts aged. Fungal activity was lower when OM was incorporated in casts. In conclusion, earthworms influence the fate of fresh OM in soil by delaying its mineralization but do not lead to long-term stabilization.