bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of new detailed (R)USLE-C-factor maps for Germany on soil loss estimates
Authors: Steinhoff-Knopp Bastian , Saggau Philipp
Published: February 2023

The (R)USLE and its many derivates are the most used models to estimate soil loss by water at regional scale. Within the (R)USLE the C-factor is used to assess the impact of crop and soil management on erosion. The exact, temporal and spatial explicit determination of the C-factor is crucial to create reliable maps on soil loss estimates, monitoring the impact of agricultural practices on soil erosion and evaluating the efficiency of policy instruments.The derivation of accurate high-resolution C-factor data for larger regions remains a challenge, as a variety of spatio-temporal data (crops/crop rotation, tillage management, interannual variation of rainfall erosivity) is needed. Based on recent improvements in calculation methods and the availability of earth observation data, the C-factor can be estimated using agricultural statistics and parcel-based information on crop cultivation. Consequently, we developed two types of spatially explicit and regional C-factor datasets for Germany, mapping the impact of agricultural practice on soil erosion in a more reliable and spatially detailed way: i) harmonized mean C-factors for municipalities for 1999, 2003, 2007, 2010, 2016 and 2020, and ii) parcel-based C-factors for the period 2017-2020 based on crop type maps from satellite data.In this contribution, we will present the implemented methods and will discuss the impact of the new detailed C-factor maps on soil loss estimates in a spatial resolution of 10 x 10 m for German cropland. The results show an increase in the C-factors for municipalities during the last two decades by 17 %. The parcel-based data reveals the C-factor ranges within the municipalities: While the mean C-factor for all parcels across Germany is 0.107 (conventional cropping; 2017-2020), the standard deviation within the municipalities ranges from 0 to 0.141 at a mean standard deviation of 0.045. This results in differences in erosion rates of up to 7 t / (ha • a), highlighting the importance of spatially explicit C-factor estimates.
Emulating internal and external components of global temperature variability with a stochastic energy balance model and Bayesian approach
Authors: Schillinger Maybritt , Ellerhoff Beatrice , Scheichl Robert , Rehfeld Kira
Published: February 2023

To characterize Earth’s temperature variability, it is necessary to better understand underlying mechanisms and contributions from internal and externally forced components. Here, we utilize a stochastic two-box energy balance model to emulate internal and forced global mean surface temperature (GMST) variability [1]. As target data for the emulation, we employ observations and 20 last millennium simulations from climate models of intermediate to high complexity. We infer the parameters of the stochastic EBM using the target data and a Bayesian approach, as implemented with a Markov Chain Monte Carlo algorithm in our “ClimBayes” software package [2]. This yields the best estimates of the EBM’s forced and forced + internal response. Applying spectral analysis, we contrast timescale-dependent variances of the EBM’s forced and forced + internal variance with that of the GMST target. Our findings show that the simple two-box stochastic EBM reproduces the characteristics of simulated global temperature fluctuations, even from comprehensive climate models. Minor deviations occur mainly at interannual timescales and are related to the simplistic representation of internal variability in the EBM. Furthermore, the relative contribution of internal dynamics increases with model complexity and decreases with timescale. Altogether, we demonstrate that the combined use of simple stochastic climate models and Bayesian inference provides a valuable tool to emulate climate variability across timescales.

[1] M. Schillinger, B. Ellerhoff, R. Scheichl, and K. Rehfeld: “Separating internal and externally forced contributions to global temperature variability using a Bayesian stochastic energy balance framework,” Chaos,  https://doi.org/10.1063/5.0106123 (2022). 

[2] M. Schillinger, B. Ellerhoff, R. Scheichl, and K. Rehfeld, “The ClimBayes package in R,” Zenodo, V. 0.1.1, https://doi.org/10.5281/zenodo.7317984 (2022). 
Results from the 2022 Groundwater Time Series Modeling Challenge
Authors: Collenteur Raoul , Haaf Ezra , Liesch Tanja , Wunsch Andreas , Bakker Mark
Published: February 2023

At the general assembly of the European Geophysical Union in 2022, the “Groundwater Time Series Modeling Challenge” was launched (Haaf et al., 2022). We challenged our colleagues in the field to model five time series of hydraulic heads measured in groundwater observations wells around Europe and North America. Part of the head data was not made available to the participants and held back as independent evaluation data. In this presentation, we will share and summarize the results from the challenge. The challenge attracted submissions from 17 teams using a variety of modeling techniques (https://github.com/gwmodeling/challenge). The models used in the submissions ranged from machine and deep learning models to empirical and bucket-type models. Many of the participants devoted notable attention to the uncertainty quantification, providing not only the results of the best-fit model but also uncertainty intervals for their models. The time to set up each model ranged from a couple of minutes to a couple of hours, indicating that models are generally set up in a limited amount of time. For most models, the majority of the time was used for the training and/or uncertainty quantification. The time spent on training showed larger differences between the models, ranging from a few minutes to more than a day for a single model. The data used to model the time series varied per model, with empirical models using less information than the machine learning models. A preliminary analysis of the modeling results showed that most of the models performed well (as measured by goodness-of-fit metrics such as NSE, MAE, KGE) in both the training and evaluation period. For one of the time series, none of the models showed a good fit with the data in the evaluation period and we suspect that a systematic change in the groundwater system may have occurred. The best-performing model differed between observation wells; none of the models outperformed all other models for all time series.  In the coming months up to the EGU 2023 General Assembly we will further analyze and synthesize the results.Haaf, E., Collenteur, R., Liesch, T., & Bakker, M. (2022). Presenting the Groundwater Time Series Modeling Challenge(No. EGU22-12580). Copernicus Meetings.
Vulnerability assessment to wind damage in a protective forest stand in the Alps.
Authors: Costa Maximiliano , Gardiner Barry , Locatelli Tommaso , Baggio Tommaso , Marchi Niccolò , Lingua Emanuele
Published: February 2023

The risk of wind damage to European forests is expected to increase due to the changed climate. Therefore, research efforts in forestry have been focussing on the development of analytical and modelling tools to improve the prediction of forests' susceptibility to wind damage, and ultimately to support forest management decisions in increasing wind resistance in forest stands. Recent catastrophic wind damage to European forests has shown that wind damage risk applies also to montane forests. Some of them are of particular importance for the various ecosystem services they provide, including protection from gravitational hazards and defence against soil erosion. At present, the available forest wind risk models have been tested and used mainly on production or planted forests in different countries, but never in the complexity of mountainous terrains. The aim of this study is to introduce a methodology for the validation of a new parametrization of ForestGALES wind risk model for the alpine environment. The parameterisation was developed through field tests (e.g., pulling tests on trees) and validated based on the observed wind damage caused by the storm Vaia, which occurred in northern Italy in October 2018, and the pre-disturbance forest characteristics. The use of this parameterisation can allow the construction of wind vulnerability maps starting from LiDAR data. Mapping vulnerability to natural disturbances, in this case, wind, is an essential tool for forest planning and management. The frequency of natural disturbances is expected to increase, as is their severity and forest management needs to target interventions to obtain more resistant and resilient forest stands. Management should aim to apply strategies to prevent future damage in a way that ensures continued protective effectiveness, guaranteeing the preservation of local communities and infrastructures.
A Thermal Wind Perspective of Driving Changes in Jet Stream Patterns
Authors: Gözlet Mehmet Sedat , Kjellsson Joakim , Latif Mojib
Published: February 2023

It is evident that the jet streams are becoming more erratic and unstable in a changing climate. We investigate changes both in position and speed of the midlatitude jet streams at 300 hPa in  31 Atmospheric Model Intercomparison Project (AMIP) runs and the ERA5 reanalysis dataset investigating the ability of the thermal wind concept to explain changes in place and the regime of the jet streams, which are disturbed by Arctic amplification, is the core of this work. All data covers the period 1979-2014.  It is revealed that the changes in jet stream magnitude and position in the multi-model mean (MMM) can largely be explained by the thermal wind. We also discovered that the AMIP models reproduce trends in jet position and strength seen in  ERA5. Yet it is a must to state that when inspecting individual models, we find that some models can reproduce ERA5 trends in NH. The large variance in modelled trends, however, leads to a poorly represented MMM. In the end, the jet stream plays a significant role in shaping global weather patterns and is affected by changing climate as becoming more wobbly and unstable. The potential impact of Arctic warming on the jet stream and how it may lead to more extreme weather events in the mid-latitudes is taken under inspection from the window of thermal wind concept with this study. 
Sangay volcano (Ecuador): multiparametric analysis of the December 2021 eruptive activity including the opening of new vents, a drumbeat seismic sequence and a new lava flow
Authors: Hidalgo Silvana , Vasconez Francisco , Battaglia Jean , Bernard Benjamin , Espin Pedro , Valade Sebastien , Naranjo Maria-Fernanda , Campion Robin , Salgado Josue , Cordova Marco , Almeida Marco , Hernandez Stephen , Pino Gerardo , Gaunt Elizabeth , Bell Andrew , Mothes Patricia , Ruiz Mario , Andrade Daniel
Published: February 2023

Sangay is a 5286 m high stratovolcano located in the southern part of the Ecuadorian Andes, about 200 km south of the capital city of Quito. Sangay is the last active volcano to the south of the Northern Andes, and has been characterized by an almost constant and continuous activity with variable periods of quiescence. During historical times, the written reports describe at least 9 major eruptions since 1628. Sangay has been instrumentally monitored by the Instituto Geofísico of the Escuela Politécnica Nacional (IG-EPN) since 2013. In May 2019, Sangay began a new eruptive period, which is still ongoing and has been categorized as the most intense in the last six decades. The main phenomena produced during this period are small explosions, ash and gas emissions, lava fountaining, lava flows and associated pyroclastic currents and secondary lahars.On 1 December 2021, from around 19:20 UTC, the seismic recordings of SAGA station began to show transient events occurring regularly. These events persisted for the next 13 hours with an irregularly accelerating rate of occurrence and increasing amplitude before merging into tremor at around 08:20 on 2 December. This sequence was rapidly followed by two explosive emissions, which were observed by the GOES-16 satellite, the first one at 09:02 and the second at 09:13. The emissions produced a 14.5 km-high gas-rich, ash-depleted eruptive column without any associated regional fallout reported. This drumbeat sequence was produced after a series of morphological changes observed through satellite images (Planet and Sentinel 2). Specifically, during the short time period considered in this study: 1) two new vents opened; 2) a landslide affected the northern flank of the volcano; 3) the first drumbeat sequence was recorded at Sangay; and 4) a new lava flow was emitted through the new northern vent. The drumbeat sequence is interpreted as being caused by the forced extrusion of this new lava flow through the new opening northern vent. Timely communication of this kind of volcanic events is favored by the creation and strict following of internal protocols within volcano observatories and the appropriate use of social networks allowing thousands of people to be reached in very short time period. The corresponding short report produced by the IG-EPN reached more than 300.000 people.
Role of climatological and geophysical controls on the landfast sea ice regime in the Hudson Bay region
Authors: Gupta Kaushik
Published: February 2023

This study investigates how both climatological and geophysical factors impact and have changed the landfast sea ice (LFI) regime in Hudson Bay and James Bay (HJB), Canada. LFI plays an important role in coastal land use practices, traditional livelihood and the formation of wetland ecosystems. Stability and extent of LFI platform is crucial to coastal communities as they use it for travel, fishing and hunting. The most vital concern raised in the Hudson Bay Summit 2022, was regarding the unpredictability of the LFI in terms of presence and thickness, which endangers the ecosystem services and livelihood of these coastal communities. The investigation relied on three sub-objectives: 1) trends of fast ice persistence and extent across HJB from 2001-2018; 2) impact of climatological factors on the landfast ice cycle, and 3) how coastal topography impacts the fast ice cycle. For this study we utilised an array of remote sensing and reanalysis products to study variables such as the landfast ice cycle (freeze-up, break-up) and persistence (CIS Ice charts, MODIS), air temperature (ERA5 reanalysis product), snow melt on land (MOD10A2 snow cover product), coastline orientation (Landsat) and coastal bathymetry (GEBCO). In addition to notable east-west contrast of the LFI climatology in HJB, the observations reveal how coastal topography impacts ice stability and extent, and eventually influences ice persistence, and how a positive feedback is created between the LFI and local air temperature. An understanding of these interlinkages are of critical importance to improve the prediction of LFI breakup in face of rapid climate warming and increased variability. The trends revealed through this study were unique compared to other Sub-Arctic regions with seasonal ice cover. Hence, a focused investigation of the factors that works as precursors of ice freeze-up and triggers break-up is proven to be vital to the continued safe use of the LFI platform.
Application of cost-efficient particulate matter measurement devices in an urban network and comparison to state-of-the-art air quality monitoring
Authors: Schrödner Roland , Alas Honey , Voigtländer Jens
Published: February 2023

22 cost-efficient (aka ‘low-cost’) commercially available particulate matter (PM) measurement devices were installed in a diverse urban area in Leipzig, Germany. The instruments measure mostly PM2.5, some additionally PM10, and are equipped with methods for quality assurance such as conditioning to a defined temperature and regular internal calibration. In order to investigate the spread between the instruments and to enable a pre-campaign calibration, all instruments were setup in the laboratory and the outside air and compared against the same reference measurements.Since July 2022, the measurement network was installed. It covers roughly 2x2 km2 and holds different urban features like residential and commercial buildings, important main roads, city parks, and small open building gaps. Within the network there is an official air quality monitoring station located directly at a main road. In addition, at two further official monitoring stations as well as at observation stations of the Leibniz Institute for Tropospheric Research instruments were installed to study the long-term performance, dependence on meteorological conditions and comparison to reference measurements. The measurements will take place until end of 2023.The cost-efficient instruments perform generally quite well after the calibration. In particularly for higher PM loads > 10 µg m-3 the agreement against references is mostly satisfying. However, under very high relative humidity and cold temperatures, some instruments lacked to condition the air sufficiently. Despite these difficulties, the chosen instruments have the potential for application in monitoring of air quality limit values, i.e. the answer the question how often are certain limits exceeded.Furthermore, differences between different local features in the observation area could be observed in e.g., the diurnal cycle but also peak and mean concentrations.This work is co-financed with tax funds on the basis of the budget passed by the Saxon State Parliament (funding number 100582357).
Certain problems related to earthquakes’ catalogs
Authors: Davtyan Vahan , Kazarian Armen , Kazarian Haik
Published: February 2023

The quality of the earthquakes’ catalogs plays the most important role in the study of seismicity, of active faults, in seismic hazard and risk assessment, etc. The quality of the catalog is evaluated by the absence of duplicate records or explosions in itself. For example, in catalogs of historical earthquakes, often the same earthquake, described by different historical sources, appears as two different earthquakes. The situation is much more complicated in instrumental catalogs, where often tremors of the surface of the earth's crust related to human vitality appear as natural earthquakes.The study of the instrumental earthquakes’ catalogs using daily histograms and remote sensing methods made it possible to identify a large number of events that, in our opinion, are not natural earthquakes. In particular, the catalog of The International Seismological Center (ISC), on the territory of Northern Kazakhstan and South-East Russia, contains more than 10,000 events that are most likely explosions, and not earthquakes. Likewise, the catalog of the National Survey for Seismic Protection of Armenia (NSSP) in the region of the Armenia-Georgia border contains more than 1,000 events that are also explosions. Similar events were recorded in Spain, Egypt, Turkey, Syria.The used methodology for the detection of false earthquakes is recommended for cleaning the instrumental catalogs of seismic events.
Evaluating the design relevance of the choice of flood frequency analysis technique in an urban coastal watershed
Authors: Lassiter Daniel , Quinn Julianne , Wright Daniel
Published: February 2023

The central challenge to flood risk management is in designing flood mitigation practices and strategies that avoid the human and economic costs of under- and over-investment. Designing to avoid these costs requires accurate recurrence probability estimates for decision-relevant flood impacts such as water depths, financial damages, and water volumes. The challenge of estimating flood impact probabilities is exacerbated in coastal settings with non-independent compound flood drivers such as rainfall and storm surge. While techniques for compound flood impact probability assessments have been proposed, insight into the decision relevance of the choice of methodology has not been explored. Our work begins to address this gap by comparing flood-volume exceedance curves resulting from three approaches in a 1.9km2 coastal urban watershed in Norfolk, Virginia. Watershed runoff and storm sewer flow are represented by 1144 links, 1128 nodes, and 869 subcatchments in a U.S. Environmental Protection Agency Stormwater Management Model (SWMM).The first flood impact probability assessment technique follows a traditional design storm approach in which the joint probability of storm surge and rainfall are mapped directly onto the modeled flood volumes. In contrast, the second and third techniques involve modeling many years of stochastically generated rainfall and storm surge time series and empirically estimating the probability distribution of the resulting flood volumes. These two techniques differ in their approach to stochastic weather generation, one fitting a probability distribution to local rainfall observations to allow for extrapolation outside the record, and the other using only historical rainfall observations but across a wider regional domain. Each approach is grounded in statistical and physical theory but leads to different estimates in flood-volume exceedance curves and their associated uncertainty. Since these estimates would influence flood mitigation design, we show that the choice of technique has design implications.
An Examination of ACCLIP (2022) Airborne Observations in the Context of their Trajectory-derived Convective Influence
Authors: Smith Warren , Pan Laura , Ueyama Rei , Honomichl Shawn
Published: February 2023

The Asian summer monsoon (ASM) has long been known as a weather system, but only recently has its role in atmospheric composition come to be explored in detail.  During boreal summer, an anticyclone forms in the upper troposphere and lower stratosphere (UTLS) over Asia which is associated with a pronounced enhancement of chemical and aerosol species lofted from the boundary layer (BL) by ASM deep convection.  In this work, we explore the transport pathways and time scales associated with ASM anticyclone shedding events, which effectively redistribute air from the anticyclone into the global atmosphere.  In particular, we launch a series of kinematic backward trajectories using ERA5 reanalysis from the western Pacific UTLS, emphasizing a novel set of airborne in situ observations taken during the summer 2022 Asian summer monsoon Chemical and Climate Impact Project (ACCLIP).  Trajectories are integrated backward in time to their most recent encounters with a satellite-derived database of convective cloud top altitudes, as well as the top of the BL.  We find that there is a consistent story between observed pollution concentrations and their associated trajectory-derived transport histories, with enhanced concentrations of BL pollutants preferentially found in air masses with shorter transport times from their convective or BL sources.  We also find that air mass contributions from eastern Asia preferentially contain higher pollutant concentrations compared to those from southern Asia.  The results provide valuable context for the measurements taken during ACCLIP and provide new insight into the role of ASM transport in global atmospheric composition.   
Investigating Emergency Room Visits for Cardiorespiratory Diseases in Alberta and Ontario, Canada in Relation to Wildfires
Authors: Flood Victoria , Strong Kimberly , Buchholz Rebecca , Magzamen Sheryl , Kuiper Grace
Published: February 2023

Carbon monoxide (CO) is released during biomass burning events, resulting in decreased air quality and leading to the formation of climate forcing pollutants. An increase in wildfires has resulted in a change to the CO seasonal cycle of the North American Pacific Northwest, when comparing 2012-2018 to 2002-2011. This trend was reported using data from the Measurements of Pollution in the Troposphere (MOPITT) instrument on NASA’s Terra satellite. Similarly, an increase in summertime CO values was identified with the Fourier Transform Infrared (FTIR) spectrometer at the University of Toronto Atmospheric Observatory (TAO), over the same time period. Studies have shown correlations between wildfire smoke exposure and healthcare utilization for cardiovascular and respiratory conditions. Monthly counts of Emergency Department admissions for cardiovascular and respiratory diseases for Alberta and Ontario are investigated in relation to wildfire events in Canada and the USA. MOPITT and TAO FTIR CO columns, the Moderate Resolution Imaging Spectroradiometer (MODIS) burned area product, and provincial burned areas from Natural Resources Canada are assessed to estimate wildfire smoke exposure in the study region. This work aims to evaluate if CO can be used as a complementary tracer for health impacts from wildfire smoke exposure.  
Numerical diffusion on vertical advection due to gravitational settling in WRF: 2D simulations
Authors: Drakaki Eleni , Mallios Sotirios , Amiridis Vassilis , Tsekeri Alexandra , Bouris Demetri , Katsafados Petros
Published: February 2023

One of the deficiencies of atmospheric dust models is that they struggle to accurately reproduce the transport of coarse and giant dust particles, according to observational evidence. Among the reasons behind that model incapacity that have been proposed in the literature, is the issue of numerical diffusion inside the advection codes of the models. In this study, we examine the importance of that issue in the WRF-L model. To do so, we update the default numerical scheme (UPWIND) which is used for the vertical advection of dust due to gravitational settling. The diffusive UPWIND scheme is replaced with a non-diffusive one, named UNO3 (third-order Upstream Non-Oscillatory scheme). To test the code performance, we perform simulations reproducing the 2D transport of a dust plume which is released at 4 km height above Cabo Verde towards Barbados. The model is initialized on 13/06/2014 at 12 UTC (which coincides with the day of the SALTRACE flight above Cabo Verde) using meteorological conditions of radiosonde from Tenerife airport and wind profile based on ECMWF model climatology. The results suggest that, in the UNO3 simulation, dust particles with a diameter 26 μm can be transported more than 500 km longer than in the BASE simulation and the dust in the atmosphere can be 10% more in the UNO3 simulation compared to the BASE simulation. In future studies, the UNO3 scheme will be tested in other aerosol types also (e.g. volcanic ash, smoke from fires).Acknowledgements: Authors acknowledge support by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “2nd Call for H.F.R.I. Research Projects to support Post-Doctoral Researchers” (Project Acronym: StratoFIRE, Project number:  3995) and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Project Acronym: D-TECT, Grant Agreement: 725698).
Trends of tropical tropospheric ozone and its precursors
Authors: Gaudel Audrey , Sauvage Bastien ,   TOAR-OPT Paper 2 "Trends" Team
Published: February 2023

As part of the Tropospheric Ozone Assessment Report Phase 2 (TOAR-II), the Ozone and Precursors in Tropics (OPT) working group counts three deliverables dedicated to quantifying 1) the distribution, 2) the trends of tropospheric ozone (O3) and its precursors (carbon monoxide, CO; formaldehyde, HCHO; nitrogen dioxide, NO2) in the tropics over the past 20-25 years, and 3) their impacts on a global scale. This presentation will focus on the trends estimate. We answer the following scientific questions: How have tropical tropospheric ozone and its precursors changed with time? What sources (e.g. anthropogenic emissions, biomass burning, lightning) drive these trends and to what extent?To accomplish this, we use both observations and model output.  The observations include in situ measurements of O3 and its precursors from surface sites, sounding balloons (SHADOZ) and instrumented aircraft (IAGOS), as well as ground-based (FTIR) and spatial (IASI, OMI, GOME-2) remote-sensed observations. Global model output come from ECHAM6-HAMMOZ, LMDZ-OR-INCA, MIROC-CHASER, CAM4-Chem, GISS-E2 and the CESM2-WACCM6 ensemble.The trends estimates are based on monthly anomalies and are calculated after considering climate variabilities such as El Niño- Southern oscillation (ENSO) and quasi-biennial oscillation (QBO).From IAGOS and SHADOZ ozone profiles, we estimate positive ozone trends between 1994 and 2019 throughout the troposphere above the Americas, Africa, India, Southeast Asia and Malaysia/Indonesia. Trends may reach up to 6 ± 1.6 ppb/decade in the free troposphere and up to 12.5 ± 2 ppb/decade in the boundary layer. There is also considerable regional variability. For example, trends are +0 to 4 ppb/decade in the free troposphere above the remote Pacific and Atlantic SHADOZ stations (1998-2019). According to OMI satellite retrievals, tropospheric ozone burden increases between 2004 and 2021 across the tropical latitude band (20˚N-20˚S) and the trends range between 0.09 Tg/yr (OMI CCD retrieval in the southern hemisphere) and 0.3 Tg/year (OMI/MLS retrieval in the northern hemisphere).The presentation will also include trends estimates of observed ozone’s precursors such as CO, NO2 and formaldehyde as well as trends estimate of ozone and its precursors from model output.
Temporal and spatial variations in the isotope hydrobiogeochemistry (H, C, O, S, Ra) of a managed river draining a lowland towards the Baltic Sea
Authors: Böttcher Michael E. , Ehlert von Ahn Cátia M. , Malik Christoph , Westphal Julia , Rach Benjamin , Nantke Carla , Jenner Anna-Kathrina , Saban Rhodelyn , Winde Vera , Schmiedinger Iris
Published: February 2023

The flow path of a river draining a lowland in the southern Baltic Sea, the Warnow River, was investigated to evaluate its freshwater composition as a source of dissolved substances to regional coastal waters. A spatial study was carried out once to follow the variations from the source to the estuary. A temporal study in the composition as a function of the season, during 6 years (2017-2022), was carried out at a site just before the river reaches the estuary. Surface water was sampled to analyze major and tracer elements, stable (H, C, O, S), and unstable (Ra) isotopes. The results show that the composition of the Warnow River along the flow path is controlled by a complex interplay between in-situ processes, exchange with the atmosphere, diffuse groundwater, and surface water inlets. On a temporal scale, pH, nutrient, and redox sensitive trace element concentrations are strongly impacted by pelagic primary production in spring. During summer and autumn, influences occurred by benthic microbial activity, associated diffusive release from soils/sediments, and surface water inlets. Throughout the investigation period, the Warnow River was a source of isotopically light CO2 to the atmosphere and DIC to the estuarine waters. The delivered DIC concentrations seem to vary with the season due to changes in biological pelagic and benthic activity. DOC was derived from a mixture of C3 organic sources and fertilizers. From concentration-discharge relationships, examples of dilution, mobilization, and chemostasis trends were found. Discharge-controlled seasonal trends are superimposed by system-internal processes and the hydrological consequences of river and drainage management. Our analysis thus provides new insights into the controls on the variations of water and solutes in a managed river at the land-sea interface as part of the regional hydrological cycle of a lowland catchment coastal water system. The study was supported by the DFG research training group BALTIC TRANSCOAST, DAAD ,  and the BMBF project CARBOSTORE/COOLSTYLE
Storyline simulations suggest dampening of 2020 Siberian heatwave analogues in warmer climates
Authors: Sánchez Benítez Antonio , Athanase Marylou , Jung Thomas , Pithan Felix , Goessling Helge
Published: February 2023

Siberia experienced an exceptionally warm first half of 2020, with temperatures peaking on 20th June, when the weather station at Verkhoyansk registered 38ºC – the highest-ever temperature recorded north of the Arctic Circle. This event led to a state of emergency declaration due to a wide range of natural and human disasters, including permafrost collapse or wildfires. Several previous attribution studies have found anomalous synoptic atmospheric circulation and human-caused climate change as major drivers of this event. However, it remains unclear how such an event would unfold in warmer climates.In this work, we have constructed analogues of this extreme event in past and future climates, so-called “storylines”, employing spectral nudging experiments using the coupled climate model AWI-CM1. In these simulations, large-scale free-troposphere winds are constrained toward ERA5 data, and the model is run for different boundary and initial conditions (pre-industrial, present, +2K, +3K, +4K climates). By doing so, this approach focuses on the less uncertain thermodynamic influence of climate on extreme events, constraining the much more uncertain dynamical changes.Our present-climate simulations realistically reproduce the observed Siberian heatwave and the exceptionally warm conditions before the event. When the different background climates are considered, on the one hand, a robust global warming amplification is obtained until spring. On the other hand, a future global warming dampening or even local cooling is observed in phase with the heatwave peak. We examine the mechanisms that damp warming during the heatwave analogue, especially changes in soil moisture and radiative fluxes. 
Metamorphic methane degassing: questions and challenges
Authors: Vitale Brovarone Alberto
Published: February 2023

Metamorphic fluids have been central in the evolution of our planet and may also control the evolution and habitability of other planetary bodies. Although a large body of literature has focused on metamorphic carbon dioxide (CO2), from its sources to its emissions into the atmosphere, methane (CH4) may also be a fundamental species in metamorphic fluids in a large variety of rock systems and produced through multiple processes. However, the geology of metamorphic methane is still largely unexplored.This study centers on metamorphic methane formation and transformation through a variety of processes and chemical systems from literature data and unpublished results, including open and closed systems in meta-sedimentary, meta-basic, and meta-ultrabasic rocks. Particular attention will be given to the types of methane that may be formed in metamorphic rocks and their classification, their distribution and abundance, and their abiotic or biotic interpretations.This contribution highlights the importance of metamorphic methane – it is more common than generally considered – and identifies a series of fundamental open questions on the topic that still need to be addressed by future work.This work is part of project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 864045).  
Asymmetry in the Terrestrial Plasma Sheet Driven by Dayside Dynamics
Authors: Dayeh Maher A. , Starkey Michael J. , Petrinec Steven M. , Fuselier Stephen A. , Sokół Justyna M. , Ogasawara Keiichi , Szalay Jamey R. , McComas David J. , Zirnstein Eric J. , Schwadron Nathan A.
Published: February 2023

The Interstellar Boundary Explorer (IBEX) mission continues to provide energetic neutral atom (ENA) observations of the heliosphere and Earth’s magnetosphere from a global perspective and including spatial, temporal, and energy information. Due to its orbit, IBEX routinely observes the magnetosphere from a side-viewing vantage point, with a field-of-view that is nearly perpendicular to the day-night plane. This enables the construction of composite ENA images at different energies (0.5 – 6.0 keV) for convected solar wind conditions, which provides global insights into different magnetospheric plasma regions and processes.Earth’s plasma sheet plays a crucial role in the global circulation of plasma throughout the magnetosphere. The structure of the plasma sheet is driven by a combination of effects including interplanetary magnetic field (IMF) and solar wind conditions, internal magnetospheric processes, and Earth’s dipole tilt angle.This work examines the structure of the plasma sheet in the X-Z geocentric ecliptic plane (GSE) using ENA images from IBEX. The thickness and extent of the plasma sheet is compared for conditions of prolonged northward and southward IMF. We report on a North-South asymmetry in the plasma sheet that is related to the IMF orientation and is driven by a combination of dayside magnetic reconnection effects and high dipole tilt. Results provide evidence of dayside reconnection driving plasma sheet dynamics.
Ecosystem C and N cycle interactions – diverse model representations and divergent model predictions versus collective empirical constraints
Authors: Stocker Benjamin D. , de Boer Hugo , Dong Ning , Harrison Sandy P. , Perkowski Evan A. , Prentice I. Colin , Rebel Karin T. , Schneider Pascal , Smith Nicholas G. , Van Sundert Kevin , Wang Han , Xu Huiying
Published: February 2023

Representations of interactions between the C and N cycles in terrestrial ecosystems are now implemented in a majority of state-of-the-art Dynamic Global Vegetation Models (C-N models). Standard models for simulating the response of individual processes to changes in N availability have not yet emerged and widely used models have not been tested against the full diversity of empirical data. Large remaining model structural uncertainty has important implications for projections and hindcasts of the land C uptake.Here, we summarise the current state of global land C balance simulations by comparing C-N models to C-only models; summarise data from field surveys and experiments to elucidate the role of soil N in controlling photosynthesis and its acclimation, stoichiometry, allocation, and growth; and demonstrate how optimality principles can guide the representation of acclimation and allocation for simulating ecosystem responses to experimental treatments of CO2 and soil N – consistent with observations. Promising model results are achieved by assuming that the atmospheric environment, including CO2, is the principal driver for photosynthetic capacities and leaf N following optimality theory of photosynthetic acclimation (Prentice et al., 2014). In turn, the functional balance hypothesis (Bloom et al., 1985) yields accurate predictions for how soil N availability and CO2 influence allocation and growth in different tissues.Our results show how confronting new theoretical approaches to simulating ecosystem C-N interactions against the collective constraints from diverse types of observations can guide model development and potentially reduce the large uncertainty in global carbon cycle projections.ReferencesBloom, Arnold J, F Stuart Chapin, and Harold A Mooney. “Resource Limitation in Plants--An Economic Analogy” Annual Review of Ecology and Systematics, 16, no. 1 (1985): 363–92. https://doi.org/10.1146/annurev.es.16.110185.002051.Prentice, I. Colin, Ning Dong, Sean M. Gleason, Vincent Maire, and Ian J. Wright. “Balancing the Costs of Carbon Gain and Water Transport: Testing a New Theoretical Framework for Plant Functional Ecology.” Ecology Letters 17, 1 (2014): 82–91. https://doi.org/10.1111/ele.12211.
Modeling EUV intensity at the top of the transition region using SPICE data on board Solar Orbiter
Authors: Rodríguez Gómez Jenny Marcela , Kucera Therese , Young Peter
Published: February 2023

The Spectral Imaging of Coronal Environment (SPICE; SPICE Consortium et al. 2020) provides an extraordinary opportunity to study the chromosphere and transition region using EUV wavelengths, e.g., Ne VIII 770 Å, C III 977 Å, O VI 1032 Å, and Lyman-β 1025 Å. We present preliminary results modeling Ne VIII 770 Å intensity using images from SPICE and the COronal DEnsity and Temperature (CODET) model. This model is based on relationships between the magnetic field, density, and temperature. It uses a flux transport model, the Potential Field Extrapolation model (PFSS), an emission model based on Chianti atomic database 10.0.2, and an optimization algorithm. In addition, we assume that the emission from the top of the transition region (Ne VIII 770 Å) can be described using the magnetic field in the coronal base at 1.014 RSun (from PFSS).
The scientific payload of the ALOFT mission to chase Terrestrial Gamma-ray Flashes and gamma-ray glows
Authors: Marisaldi Martino , Østgaard Nikolai , Ullaland Kjetil , Yang Shiming , Qureshi B. Hasan , Søndergaard Jens , Mezentsev Andrey , Sarria David , Lehtinen Nikolai , Lang Timothy J. , Christian Hugh , Quick Mason , Blakeslee Richard , Grove J. Eric , Shy Daniel
Published: February 2023

ALOFT (Airborne Lightning Observatory for FEGS and TGFs) is a flight campaign designed to observe Terrestrial Gamma-ray Flashes (TGF) and gamma-ray glows close to their production source. The campaign consists of 50 flight hours of a NASA ER-2 research aircraft taking off from Florida and is scheduled for July 2023. The ER-2 cruise altitude of 20 km allows flying over active thunderstorms in the Gulf of Mexico and Caribbean region, one of the most TGF-active region on the planet. The main challenge for TGF detection at close distance is the large variability in the expected gamma-ray flux, spanning four orders of magnitude depending on the radial distance from the source. To cope with this challenge, the ALOFT gamma-ray payload consists of several detectors of different size, made of different materials and readout sensors, designed to cover 4 orders of magnitude dynamic range on the typical TGF/gamma-ray glow energy range (~100 keV - ~40 MeV). In addition, the payload includes the Fly’s Eye GLM Simulator (FEGS), an array of imaging photometers sensitive at different wavelengths, and electric field change meters, and the Lightning Instrument Package (LIP), giving three component electric field measurements. The synergy between airborne gamma-ray, optical and electric field measurements, combined with ground-based radio observations, will provide a unique set of observations to constrain the source properties and their physics. This presentation will focus on the ALOFT scientific payload and the system architecture.
Comparing extreme event statistics in Dst, SYM-H and SMR geomagnetic indices.
Authors: Bergin Aisling , Chapman Sandra , Watkins Nicholas , Moloney Nicholas , Gjerloev Jesper
Published: February 2023

Extreme space weather events are rare, and quantifying their likelihood is challenging, often relying on geomagnetic indices obtained from ground-based magnetometer observations that span multiple solar cycles. The Dst index ring-current monitor, derived from an hourly average over four low-latitude stations, is a benchmark for extreme space weather events, and has been extensively studied statistically. We apply extreme value theory (EVT) to two geomagnetic ring current indices: SMR, (derived from up to 120 stations) and SYM-H (derived from 6 stations). EVT analysis reveals a divergence between the return level found for Dst, and those for SMR and SYM-H, that increases non-linearly with return period. For return periods below 10 years, hourly averaged SMR and SYM-H have return levels similar to Dst, but at return periods of 50 and 100 years, they respectively exceed that of Dst by about 10% and 15% (SYM-H) and about 7% and 12% (SMR). One minute resolution SMR and SYM-H return levels progressively exceed that of Dst; their 5, 10, 50 and 100 year return levels exceed that of Dst by about 10%, 12%, 20% and 25% respectively. Our results suggest that for more extreme events, these geomagnetic indices are not directly interchangeable, instead they contain different, complimentary information and should be used together in any detailed analysis. Such an analysis may improve the correlation between return levels and the impact of severe geomagnetic storms.  
Hydrosignalling : How air gaps in soils alter the distribution of root water and hormones fluxes, thereby blocking root lateral branching
Authors: Couvreur Valentin , Mehra Poonam , Pandey Bipin K. , Draye Xavier , Bennett Malcolm J. ,   co-authors
Published: February 2023

Plant roots exhibit plasticity in their branching patterns to forage efficiently for heterogeneously distributed resources, such as soil water. The xerobranching response represses lateral root formation when roots lose contact with water (e.g. in “air gaps”), and provides an experimental model to study root adaptive responses to transient water stress.To discover the mechanistic basis of xerobranching, soil- and agar-based xerobranching bioassays were developed. As levels of the abiotic stress signal abscisic acid (ABA) increase in root tips during transient water stress, we observed that tomato, maize and Arabidopsis mutants deficient in ABA are disrupted in xerobranching response. Using novel ABA biosensors and mutants, we showed that when reaching an air gap, it takes about half a day for ABA originating from phloem tissues to radially travel through the unloading zone and accumulate in epidermal tissues.When root tips lose contact with water, could the direction of water flow across root tissues change, and trigger the outwards accumulation of ABA, acting as a “hydrosignal” ? Our 3-dimensional root micro-hydrological model of solute advection-diffusion “MECHA” supports the following hypotheses :Such a reversal of radial water flow direction may happen in the root elongation zone, as cell elongation may not be fed by water absorbed at the root surface anymore, and therefore water for cell elongation (e.g. in the epidermis) entirely relies on phloem as a water source.
If water soluble hormones such as ABA “ride” on water fluxes through plasmodesmata and along cell walls, it would take them about 8 hours to accumulate to levels comparable to concentrations observed in phloem cells. This timing is compatible with our experimental observations.
From there on, our Arabidopsis mutants reveal that ABA uses plasmodesmatal closure to lock up the symplastic radial pathway that is necessary for auxin to initiate lateral root branching.In conclusion, our study reveals how roots might adapt their branching pattern to heterogeneous soil water conditions by linking changes in hydraulic flux with dynamic hormone redistribution.This work includes material recently published in Science, under the following link: https://doi.org/10.1126/science.add377