bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal variation of nitrous oxide flux and aeration/water stress at different water table levels
Authors: Politi Moncada Mansonia , Longo Matteo , Dal Ferro Nicola , Morari Francesco
Published: February 2023

Patterns of nitrous oxide (N2O) emissions related to water-filled pore space and gas diffusivity have been described as evidence of denitrification activity. However, the complexity of factor combinations in managed agroecosystems calls for comprehensive studies relating to N2O emissions and water content dynamics, both spatially and temporally. This study examined the impact of two water table levels and free drainage (60 cm, 120 cm and free drainage, WT60, WT120 and FD) in combination with land management (conservation and conventional agriculture) on the seasonal variation of surface N2O flux and aeration/water stress on the soil profile. N2O emissions and volumetric water content dynamics were measured on a lysimeter experiment over three years (2018-2020). Preliminary results show that N2O emissions were driven by fertilization over time irrespective of water table level and land management. In the topsoil, WT60 and WT120 promoted longer periods of aeration stress under conservation agriculture compared to conventional, whereas FD increased water stress days under conventional agriculture. At 30 and 60 cm depth, water content under FD remained mostly within the range of nonlimiting for plant growth, and under WT60 and WT120 was generally above the aeration limit in-season and over time. Correspondently, calculated relative gas diffusivity was limiting for conservation agriculture in the topsoil compared to conventional agriculture, and below the anoxia threshold for both land management at 30 and 60 cm depth. This suggests that the subsoil could become a potential hotspot for N2O production under shallow water levels. Cumulative surface N2O appears to be related to the cumulative number of aeration stress days derived from the nonlimiting water range, with variation across years and land management.
Satellite times-series analysis and assessment of the BFAST algorithm to detect possible abrupt changes in forest seasonality utilising Sentinel-1 and Sentinel-2 data. Case study: Paphos forest, Cyprus
Authors: Theocharidis Christos , Gitas Ioannis , Danezis Chris , Hadjimitsis Diofantos
Published: February 2023

Climate change can be described as the dominant factor all these decades concerning changes in forest phenology while, at the same time, temperature affects the development time (Barrett & Brown, 2021; X.Zhou et al., 2020; Suepa et al., 2016). Satellite image-time series data have proven their value regarding forest health and forest phenology observation. Monitoring continuous plant phenology is critical for the ecosystem at a regional and global level since the high sensitivity of vegetation life cycle to climate change; the so-called phenophases are essential biological indicators to comprehend how climate change has impacted these ecosystems and how this will change the ensuing years. (Buitenwerf, Rose, and Higgins 2015; Johansson et al. 2015).  This study conducts a time-series analysis using the breaks for additive season and trend (BFAST) time-series decomposition algorithm, to detect possible abrupt changes in forest seasonality and the impacts of extreme climatic events on forest health, examining Sentinel-1 and Sentinel-2 data for the period 2017-2021. The backscatter coefficient from Sentinel-1, Normalised Difference Moisture Index (NDMI), Enhanced Vegetation Index (EVI), and Green Chlorophyll Index (GCI) were created by Sentinel-2 and assessed to find possible correlations between them. All the satellite time-series data derived through the Google Earth Engine platform.The study area is the Paphos Forest, managed by the Department of Forest which could be described as a representative Mediterranean forest; thus, it is vital to monitor it because Mediterranean forests are expected to experience the first climate change in Europe. More specifically, the study focus on the Nortwest, West and Southwest areas of the Paphos Forest since the SAR images are from Ascending orbit. Moreover, Paphos forest has unspoiled vegetation, and a highly reduced number of forest wildfires have occurred in recent years, favouring the reliability of the research's results.   AcknowledgementsThe authors acknowledge the 'EXCELSIOR': ERATOSTHENES: Excellence Research Centre for Earth Surveillance and Space-Based Monitoring of the Environment H2020 Widespread Teaming project (www.excelsior2020.eu). The 'EXCELSIOR' project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No 857510, from the Government of the Republic of Cyprus through the Directorate General for the European Programmes, Coordination and Development and the Cyprus University of Technology.
Gravimetric network of the Eastern part of the North of Algeria
Authors: bayou yasser , Bouyahiaoui Boualem , Abtout Abdeslam , Berguig Mohamed Cherif , A. Renaut Rosemary
Published: February 2023

The northern of Algeria is located between the limit of the African and Eurasian plates. It is known for its geological heterogeneity. This part is experienced with few geophysical data. Among this data, the gravimetric survey can reveal several pieces of information about geological complexity. Although, before any achievement of gravimetric data, it is imperative to perform a gravimetric network. In this work, we present the full steps of implementing the gravimetric network located in the eastern part of the north of Algeria, combined with the processing in detail, using a manual method. The new gravimetric network is situated in the main area of the Guelma basin and its surrounding area (07° 00’; 08° 00 ’E and 36° 00’; 36° 45’N). This network encompasses thirty-nine gravimetric reference stations, linked to the Algerian gravity network. It forms one polygon that is built with 61 triangular loops connected to each other with 99 links. The initiation of the method used, and all stages of the gravity data are described. The average of the gap of gravity values at each station is about 11 µGal. the campaign was carried out using a terrestrial Scintrex CG3 gravimeter. The new gravimetric network of the north eastern part of Algeria is adjusted by means of the ginning method. The principal purpose of the realization of this gravimetric network is to provide a high quality for all future works with respect to the gravimetric studies in the north eastern part of Algeria.
A workflow to study land subsidence based on InSAR analysis and hydro-mechanical modeling: A case study of Hanoi, Vietnam
Authors: Tran Hong Ha , Busch Wolfgang , Butscher Christoph
Published: February 2023

In recent years, land subsidence has been intensively studied due to its severe impacts on urban communities and the environment. Amongst others, groundwater withdrawal is suspected to be the main trigger for such land subsidence. A prominent example is the Red River Delta in Northeastern Vietnam, where Hanoi is located. Radar remote sensing for mapping ground movement has been successfully applied for Hanoi City to quantify the land subsidence. Specifically, SAR data at the X, C, and L bands have been used, mainly based on the small baseline subset (SBAS) and Persistent Scatterer InSAR (PSInSAR) methods for extracting deformation in the urban setting of Hanoi from 1995 to the present. In these previous studies, line-of-sight land deformation was converted into the vertical direction with the assumption that horizontal movement is insignificant. However, a detailed analysis of the hydro-mechanical processes triggering the subsidence would strongly benefit from more complete InSAR deformation data, accounting also for horizontal movement. Therefore, the study applies PSInSAR to process both ascending and descending Sentinel-1 data acquired from 2017 to the end of 2019 to extract both vertical and horizontal (along the east-west direction) deformation in the study area. Our results show that in some areas, total displacement adds up to 32 mm/y in the vertical (subsidence) and 17 mm/y in the horizontal direction, indicating that horizontal movements are not negligible when it comes to interpreting deformation and relating it to hydro-mechanical processes in a heterogeneous subsurface. An interdisciplinary workflow is introduced that illustrates how remotely sensed subsidence data can be interpreted with the help of a geological subsurface model and coupled hydro-mechanical simulations conducted with numerical multi-physics software. We present the data basis and model set-up for the planned modeling study with the open-source software platform OpenGeoSys.
CME real time prediction using HI beacon data confined by a Solar Orbiter arrival
Authors: Amerstorfer Tanja , Bauer Maike , Möstl Christian , Laker Ronan , Horbury Timothy S. , Dumbovic Mateja , O'Brien Helen , Fauchon-Jones Edward J. , Davies Jackie A. , Harrison Richard A. , Barnes David
Published: February 2023

On March 7, 2022 at 22:49 UT, a coronal mass ejection impacted Solar Orbiter, located almost exactly on the Sun-Earth line at a heliocentric distance of 0.49 AU. This exceptionally advantageous spacecraft location yielded the opportunity of constraining the ensemble of our CME propagation model, ELEvoHI, in a way that only the most accurate ensemble members at Solar Orbiter (in terms of predicted arrival time) contributed to the prediction for L1. ELEvoHI is based on STEREO's heliospheric imager data that is available in real time only in a reduced quality, i.e. lower spacial and time resolution compared to science data. However, considering the arrival at Solar Orbiter it was possible to precisely predict the arrival of the CME sheath at L1 in real time. These results emphasize the benefit of having (a) spacecraft situated between the Sun and Earth as an early warning system for Earth-directed CMEs.
Fast recovery of suppressed Norway spruce trees after selection harvesting on a drained peatland forest site
Authors: Lehtonen Aleksi , Leppä Kersti , Rinne-Garmston Katja , Sahlstedt Elina , Schiestl-Aalto Pauliina , Heikkinen Juha , Young Giles , Korkiakoski Mika , Peltoniemi Mikko , Sarkkola Sakari , Lohila Annalea , Mäkipää Raisa
Published: February 2023

Continuous cover forestry (CCF) has been promoted as an environmentally sustainable option for drained peatlands. The CCF management has been challenged due to potentially lower tree growth compared to traditional even-aged management, especially with suppressed trees that are released during a selection harvesting under CCF management.Our objective was to quantify the time lag of stem diameter growth response of suppressed Norway spruce trees (Picea abies Karst.) after a selection harvesting compared to that of dominant trees. We also tested if the carbon assimilation of the trees increased immediately after selection harvesting. We used radial increment cores from suppressed Norway spruce trees to estimate the impact of selection harvesting on the diameter growth and intrinsic water use efficiency (iWUE). We measured carbon isotope composition (δ13C) of wood, to quantify how the reduced competition between trees altered iWUE and its components, the photosynthetic rate (A) and stomatal conductance (g).The study was conducted in the Lettosuo experimental site on fertile forestry drained peatland area in southern Finland. Approximately 70 % of the initial stand area (18.5 ha) was harvested according to CCF principles by applying selection harvesting, and the rest of the area was divided to intact control area and to clear-cut area. In the study site, by selection harvest, trees were removed from multiple age classes, but especially mature trees individually or in a small groups were taken away to maintain uneven-aged structure of the forest. All the target trees grew in the similar competitive position before selection harvesting.Our results show that there was a delay with the diameter growth of the suppressed trees to selection harvesting, whereas the most significant growth-enhancing effect occurred three-four years after selection harvesting. In contrast to the delay in the increment, the photosynthetic rate relative to stomatal conductance increased immediately after selection harvesting, as shown by the instant 2.5‰ increase in δ13C to a post-harvest level.Our results show that carbon uptake increased immediately for suppressed Norway spruce trees after selection harvesting, but the harvest did not induce a clear increase in stem diameter growth during the first years after the harvest.
Analysis of polarimetric GNSS-R airborne data as a function of land use
Authors: Dassas Karin , Zribi Mehrez , Fanise Pascal , Dehaye Vincent , Ayari Emna , Le Page Michel
Published: February 2023

In recent years, GNSS-R data have shown great potential in monitoring and characterizing the states of continental and ocean surfaces. Numerous studies have also demonstrated the potential of GNSS-R polarimetry, showing high precision for the estimation of surface properties such as vegetation, soil moisture, and flooded areas. Very generally, on continental surfaces, the most commonly used observable is reflectivity under the assumption of dominance of the coherent component over the incoherent component. The objective of this study is to analyze GNSS-R data variations as a function of land cover using airborne measurements obtained with the GLObal Navigation Satellite System Reflectometry Instrument (GLORI), which is a polarimetric instrument. GNSS-R measurements were acquired at the agricultural Urgell site in Spain in July 2021. In situ measurements describing the soil and vegetation properties were then obtained simultaneously with flight measurements. For land use mapping, supervised classification is performed based on the Level-2A Sentinel-2 time series for the summer season of the 2021 cloud-free selected and ground-truth observations.The behavior of the observable copolarization (right-right) reflectivity  and the cross-polarization (right-left) reflectivity as a function of land use is discussed.The distribution of coherent and incoherent components in the reflected power is estimated for different types of land cover (maize, alfalfa and grass, apple and pear orchards, water and urban constructions and roads).The dependence of our observations on moisture is analyzed by examining the evolution of a  (percentage of the incoherent component relative to the total scattering power) over the three flights, since the first flight was conducted in a very dry context, the second flight was conducted after precipitation, and the third flight was conducted after the beginning of the drying process.
Model calculations of the contribution of tropospheric SO2 to the stratospheric aerosol layer
Authors: Nalapalu Chiranjeevi Srinivasan , Wohltmann Ingo , Rex Markus , Höpfner Michael
Published: February 2023

The stratospheric aerosol layer is important for stratospheric chemistry, climate change and in geo-engineering. Yet the processes governing the transport of sulfur to the stratosphere are poorly quantified. We present model calculations of the chemistry of sulfur dioxide (SO2) and its transport to the stratosphere and perform numerous sensitivity runs to assess the range of uncertainty of these calculations. The transport model is based on backward trajectories from the ATLAS model driven by ECMWF ERA 5. A simplified chemical box model constrained by CAMS data is used to calculate the SO2 chemistry. Sensitivity experiments explore the sensitivity to changes in OH, H2O2, DMS, cloud water, cloud pH value and in the driving analysis data. Input parameters were varied and their differences have been explored. The effect of El Nino and La Nina on SO2 transport was investigated. The SO2 reaching the stratosphere was quantified and the sources in the troposphere were determined. The model’s results were compared to POSIDON Aircraft measurements. 
Investigating the typicality of the dynamics leading to extreme temperatures in the IPSL-CM6A-LR model
Authors: Noyelle Robin , Yiou Pascal , Faranda Davide
Published: February 2023

Understanding the physical mechanisms leading to extremes of quantities of interest in dynamical systems remains a challenge. Under mild hypothesis, the application of the theory of large deviations to dynamical systems predicts the convergence of trajectories leading to extremes towards a typical, i.e. most probable, one called the instanton. In this paper, we use a 2000 years long simulation of the IPSL-CM6A-LR model under a stationary pre-industrial climate to test this prediction. We investigate the convergence properties of trajectories leading to extreme temperatures at four locations in Europe for several variables. We show the convergence of trajectories for most physical variables, with some geographical and temporal discrepancies. Our results are coherent with the most probable path prediction and suggest that the instanton dynamics leading to extremes is a relevant feature of climate models.
CAMELS-spat: catchment data for spatially distributed large-sample hydrology
Authors: Knoben Wouter , Clark Martyn
Published: February 2023

The recent publication of large-sample datasets for hydrologic modeling and analysis has led to a revival of comparative hydrology. The “CAMELS” branch of these datasets currently provide catchment attributes and meteorological time series for basins located in the United States, Chile, Brazil, Australia and Great-Britain, with a dataset for France under development. A key characteristic of these datasets is that information is provided as catchment-averaged data; i.e. each catchment is treated as a lumped entity with no spatial variability. Some progress is being made to extend large-sample hydrology to include spatially distributed data, most notably by the recent LamaH dataset which covers part of Central Europe.Here we present progress on developing a continental domain dataset for large-sample hydrology intended for spatially distributed modeling and analysis. Our domain covers the United States and Canada, expanding both geographically and climatically on the region covered by the LamaH dataset. We focus mostly on relatively undisturbed headwater catchments, because accurate data on water management policies and infrastructure can be difficult to obtain. Our aim is to provide the necessary data for process-based modeling and analysis at a sub-daily temporal resolution. 
Substantial future ice shelf melting projected in West Antarctica regardless of fossil fuel scenario
Authors: Naughten Kaitlin , Holland Paul , De Rydt Jan
Published: February 2023

Mass loss from the West Antarctic Ice Sheet, driven by interactions with the ocean causing melting of ice shelves, is currently Antarctica’s largest contribution to sea level rise. It is not well known how ice shelf melting may evolve in the future, and to what degree this response can be tempered by climate change mitigation. Here we present the most comprehensive future projections of the Amundsen Sea region to date: nearly 4000 years of ice-ocean simulations considering different fossil fuel scenarios and pathways of internal climate variability. All scenarios exhibit significant and widespread future warming of the Amundsen Sea ocean and increased melting of its ice shelves. Even under the most ambitious scenario, where global warming is limited to 1.5°C, the Amundsen Sea warms three times faster than in the historical period. The warming is driven by an increase in onshore transport of warm Circumpolar Deep Water, causing the present-day oscillations between warm and cold periods to converge towards a state of permanent warmth. Until the 2070s, all scenarios are statistically indistinguishable in terms of Amundsen Sea warming; after that, it is only the extreme RCP 8.5 scenario which diverges from the others. Furthermore, the additional ice shelf melting in RCP 8.5 is concentrated in regions which are less glaciologically important for sea level rise. These results suggest that climate mitigation has limited power to prevent West Antarctic ice loss, and that a substantial baseline of future sea level rise is already committed. 
Optimizing variable rate irrigation using model-based dynamic prescription maps
Authors: Morari Francesco , Gabrieli Davide , Furlan Lorenzo , Furlanetto Jacopo , Misturini Davide , Sobrino Jose , Skokovic Drazen , Corbari Chiara
Published: February 2023

Variable rate irrigation is usually based on prescription maps delineated according to a static approach. Irrigation rate and timing are optimised by sensor and/or modelling-based methods applied within homogenous zones whose spatial distribution is kept constant during the crop season. The objective of this study was to develop a procedure based on the combination of the crop-energy-water balance model FEST-EWB-SAFY with remote sensing data of vegetation variables and land surface temperature to generate dynamic irrigation prescription maps. The crop-energy-water balance FEST-EWB-SAFY model couples the distributed energy-water balance FEST-EWB, which allows computing continuously in time and distributed in space both soil moisture and evapotranspiration fluxes, and the SAFY (simple model for yield prediction and plant development).The model was tested in a 30-ha field cultivated with soybean in 2022 at Ceregnano, in the lower zone of the Po Valley (Italy). Irrigation was provided by 270m long lateral move irrigation machine, equipped with a precision irrigation system with a lateral resolution of 34 m. The model was pixelwise calibrated with remotely sensed land surface temperature (LST, RMSE 1.3 °C) and leaf area index (RMSE 0.45) as well as local measured soil moisture at 10cm and 50cm depth (RMSE 0.04). Four dynamic prescription maps were generated during the season, calculating the pixel-by-pixel difference between the field retention capacity and the daily average of the 50-cm soil moisture profile. Dynamic variable rate irrigation was compared with a conventional irrigation system according to an experimental block design with three replicates and evaluated in terms of crop yield, irrigation volumes and water use efficiency.FEST-EWB-SAFY allowed the creation of dynamic maps that captured the crop water requirement variability originated by the interaction of ET, soil properties and field management. Compared with the conventional system, there was a significant increase in water use efficiency, but not in crop yield. These results confirm that the model-based dynamic prescription maps could be used to optimize variable irrigation in highly spatio-temporal dynamic cropping systems
Non-Planetary Science Potential of the Prospective Uranus Mission
Authors: Soyuer Deniz , Zwick Lorenz , Bucko Jozef , D'Orazio Daniel , Saha Prasenjit
Published: February 2023

With the recent announcement of a flagship Uranus mission by NASA’s Planetary Science and Astrobiology Decadal Survey for 2023-2032, Uranus might be visited again by a spacecraft for the first time after the Voyager II mission in the late 1980s. The prospective Uranus Orbiter mission is not only significant for learning about the Uranian system, but also an exceptional opportunity for non-planetary radio science, due to long spacecraft cruise periods and travel distances.

Proposed mission plans to Uranus involve 9 years of cruise time, during which the scientific potential of the spacecraft is not fully utilized. Radio communication between Earth and a distant spacecraft presents a unique case for investigating various phenomena via Doppler tracking, such as:
(i) Searching for low-frequency gravitational waves from supermassive blackhole binary mergers.(1)
(ii) Placing constraints on the local dark matter content in the solar system and testing alternative theories of gravity.(2)
(iii) Localizing the hypothetical Planet 9.(3)
To this end, we estimate the feasibility of all these prospects for different physical models, as well as varying sensitivities of the Earth-spacecraft radio link. Our findings suggest that, with a significant but realistic improvement from the Cassini-era Doppler link sensitivity, there is a good chance of realizing all of the proposed cases above. 

(1) Soyuer D., Zwick L., D’Orazio D., Saha P., 2021, MNRAS, 503, L73, (2) Zwick L., Soyuer D., Bucko J., 2022, A&A, 664, A188,  (3)Bucko J., Soyuer D., Zwick L., (in prep.)
Numerical analysis of scaling formation in geothermal systems: application in bubble columns
Authors: Omidi Mohamad , Baumann Thomas
Published: February 2023

Scaling summarizes precipitation of solids on the surface of pipes, heat exchangers, and other equipment in various industrial processes, including geothermal systems. Scalings in carbonate systems, which make up one of the most important geothermal reservoirs, are caused by a disruption of the lime-carbonic acid-equilibrium. Increasing temperatures (e.g. at the motor of a pump) lead to oversaturation. Decreasing pressure itself also leads to oversaturation but also to the formation of gas bubbles and stripping of CO2. The latter causes a shift to higher pH-values and massive oversaturation and affects most facilities in the North-Alpine Foreland Basin. The omnipresent scalings reduce the efficiency and may cause significant downtimes. It is therefore important to predict the amount of scalings along the geothermal cycle.While current hydrogeochemical models are capable to predict the risk and position of scalings, they are falling short with regard to the temporal development. They generally over-predict the amount of scalings which indicates that limiting processes, e.g. diffusion limited crystal growth, partial volume effects, and local equilibria have to be considered. This requires a combination of a fluid dynamics model and a hydrogeochemical model. Since the geothermal fluids are quite heterogeneous in their hydrochemical composition (from fresh water to brine) and both, equilibrium constants and kinetic rate constants, depend on the hydrochemical composition, coupling to an established hydrogeochemical model is favored to shorthand implementations of individual reactions.Benchmark data for such improved models can be obtained from bubble columns. Here, a gas is injected at the bottom of a usually transparent pipe filled with a fluid of known chemical composition and the effects of stripping (or gas augmentation) can be monitored with high temporal and spatial resolution. The fluid flow is accessible through tracking of particles and gas bubbles. Bubble columns are also used in different industrial processes, providing additional applications for the developed model.In this contribution we show the coupling of OpenFOAM, a very versatile computational fluid dynamics model, with PhreeqC, a widely used hydrogeochemical model, to simulate the effects of stripping on the formation of carbonate precipitates on the pipe walls and in dispersion. The model is compared to experimental data and a hybrid hydrogeochemical model which used an effective mass transfer rate for the gas-water exchange reaction as fitting parameter to cover the rate limiting processes.
History and dynamics of Fennoscandian Ice Sheet retreat and contemporary ice-dammed lake evolution and faulting in the Torneträsk area, northwestern Sweden
Authors: Ploeg Karlijn , Stroeven Arjen
Published: February 2023

The prospect of future sea level rise due to the melting of Antarctica and Greenland affirms an urgency to better understand the deglaciation dynamics of ephemeral ice sheets. The history and dynamics of Fennoscandian Ice Sheet retreat, reconstructed from glacial geomorphology, can serve as a useful analogue. The recent release of a 1 m LiDAR-derived national elevation model for Sweden reveals new insights, even for well-studied areas such as the Torneträsk region of northwestern Sweden. This study aims to refine the history of retreat and dynamics of the ice sheet margin during deglaciation based on glacial geomorphological mapping. The mapped glacial landforms are, by means of an inversion model, grouped in swarms representing spatially and temporally coherent ice sheet flow systems. Ice-dammed lake traces such as raised shorelines, perched deltas, and outlet channels, allow for the precise identification of ice margins. A strong topographic control on retreat patterns is evident, from ice sheet disintegration into separate lobes in the mountains to orderly retreat in the low-relief areas. Eight ice-dammed lake stages are identified for the Torneträsk basin, of which the lowest stages demonstrate the lake covered a larger extent than previously thought. The lake finally drains through Tornedalen by means of a glacial lake outburst flood. The Pärvie fault, the longest-known glacially-induced fault in the world, offsets the six oldest raised shorelines of Torneträsk. The implication of this new finding is that the Pärvie fault ruptured partially underneath the ice sheet in response to glacial isostatic adjustment to the unloading of the crust. Precise dating of the two bracketing raised shorelines would pinpoint the age of the Pärvie fault. Collectively, this study provides data for better understanding the history and dynamics of the Fennoscandian Ice Sheet during final retreat, such as interactions with ice-dammed lakes and re-activation of faults through glacial isostatic adjustment.
Mechanisms behind ocean variability in transient simulations of the early deglaciation
Authors: Kapsch Marie-Luise , Klockmann Marlene , Mikolajewicz Uwe
Published: February 2023

The last deglaciation was accompanied by a gradual warming with superimposed abrupt climate changes. In transient simulations of the last deglaciation with the comprehensive Max Planck Institute Earth System Model (MPI-ESM) we show that the timing and occurrence of abrupt climate changes are highly dependent on the utilized ice-sheet boundary condition. Simulations with different ice-sheet reconstructions show that the variability of North Atlantic surface temperatures are dominated by the timing and amplitude of meltwater fluxes from ice sheets, as derived from reconstructions. While some abrupt climate events (e.g. the Younger Dryas) only occur under certain boundary conditions in the transient simulations, other climate events such as the Bølling Allerød warming (about 14.7-14.2 ka BP) cannot be simulated with any of the applied and widely used reconstructions. However, in a sensitivity experiment with changing ice sheets but no addition of meltwater into the ocean, the North Atlantic experiences a warming during the time of the Bølling-Allerød. This warming is associated with a reorganization of the ocean circulation and deep-water formation sites. Prior to this reorganization, during the glacial and early part of the deglaciation, a rather zonal jet stream maintains a strong subpolar gyre in the North Atlantic. In addition, salty and dense water masses form in the Arctic. Until about 16.5 ka BP the Arctic freshens significantly and the surface elevation over the Laurentide ice sheet reduces. The latter leads to a shift in the atmospheric circulation at around 14.2 ka BP. The resulting changes in wind stress strongly reduce the eastward extent of the North Atlantic subpolar gyre. Here, we examine the physical mechanisms behind the reorganization and explore additional simulations with fixed deglacial key parameters (e.g. CO2, insolation, ice sheets) to identify the key drivers of the climate changes during the early deglaciation and Bølling Allerød.
A low cost real-time kinematic dGPS system for measuring glacier movement
Authors: Martinez Kirk , Hart Jane , Attia Sherif , Bragg Graeme , Corbin Marcus , Jones Michael , Kuhlmann Christian , Weaver Elliot , Wells Richard , Christou Ioannis , James Emily
Published: February 2023

Glacier movement has been measured over the years using commercial units such as those from Leica. The aim is to measure point movements on the glacier surface in order to capture fine-grained data about its movement. This can also help to calibrate satellite-based approaches which have much lower resolution. Commercial dGPS recorders cost thousands of Euros so our project is creating a solution using new lower cost dGPS boards which could enable their use by more earth scientists.The u-blox Zed-F9P based boards from Sparkfun can be used as a base station to send dGPS corrections to “rover” units on the glacier via a radio link. Each measurement is accurate to about 2cm depending on conditions. In our design the radio is used by the rovers to forward good fixes back to the base station, which then uses off-site communications to send the data home. Two types of internet link have been enabled: using a nano-satellite board (by SWARM) and a more traditional GSM mobile phone board (for locations with coverage). Both these boards are also available from Sparkfun – making most of the modules off-the-shelf. However our power supply is optimised to save power and charge the lithium ion battery from a solar panel. A real-time clock chip is used to wake up the system to take readings and transmit data, so the sleep power is only 0.03 mW enabling a year-long lifetime. The whole system is controlled by a Sparkfun Thing Plus SAMD51 which provides the required four serial connections and a circuitpython  environment. The full system will be installed in Iceland in the summer of 2023 and replace the previous prototype based on Swift Piksi Multi units which had shown the measurement principle to be sound.
Assessing the state of the adoption of Nature-based Solutions for coastal risk management in the Mediterranean basin
Authors: Motta Zanin Giulia , Muwafu Simon Peter , Máñez Costa María
Published: February 2023

The ineffectiveness of traditional grey engineering infrastructures to counteract coastal risks such as erosion and flooding, combined with the exacerbation of climate change impacts, is leading scientists, experts and decision makers to devise and implement more adaptive, cost-effective, resilient, sustainable and environment-friendly risk management measures. Nature-based Solutions (NbSs), as an alternative or complement to traditional grey infrastructures for coastal risk management, are gaining importance in the international and EU debate. The Mediterranean Basin is considered one of the most vulnerable regions worldwide mainly due to its population density and concentration of economic activities along the coasts and its borderline climatic balance. It is defined as one of the most critical erosion hotspots in Europe, due to the degradation of coastal areas and the overexploitation and unsustainable practices along the coasts and in the sea, heavily affecting beach tourism, agriculture and fishing activities. Moreover, the Mediterranean coasts are affected by impacts of other phenomena (e.g. storms, floods), exacerbated by climate change. To mitigate and adapt to such environmental and climatic changes, NbSs are considered a promising step-forward, as it is based on the principle that the enhancement and protection of natural processes provide multiple benefits to society, thus ensuring a sustainable provision of benefits and co-benefits and counteracting the negative climate change impacts.This paper seeks to bring a comprehensive understanding of the state of the adoption of NbSs for coastal risk management in the Mediterranean. To assess the goal, an in-depth analysis based on a literature review of past and current implemented NbSs for coastal risk management in the Mediterranean has been performed. Starting from 162 scientific papers and documents, only 23 fit the goal of the work. Through the support of an innovative four-dimensional matrix, the operationalized classification of the NbSs has been performed. The main result reveals a lack of consideration of NbSs for coastal risk management in the Mediterranean leading to difficulties in helping to facilitate NbS mainstreaming and uptake.The current study raises the necessity to examine the reasons behind the difficulties in implementing  NbSs for coastal risk management in a complex system such as the Mediterranean, by identifying strengths and gaps.
Precipitation measurement based on satellite data and machine learning
Authors: Yi Lu , Gao Zhangyang , Shen Zhehui , Lin Haitao , Liu Zicheng , Ma Siqi , Li Stan Z. , Li Ling
Published: February 2023

Satellite infrared (IR) data, with high temporal resolution and wide coverages, have been commonly used in precipitation measurement. However, existing IR-based precipitation retrieval algorithms suffer from various problems such as overestimation in dry regions, poor performance in extreme rainfall events, and reliance on an empirical cloud-top brightness-rain rate relationship. To solve these problems, a deep learning model using a spherical convolutional neural network was constructed to properly represent the Earth's spherical surface. With data inputted directly from IR band 3, 4, and 6 of the operational Geostationary Operational Environmental Satellite (GOES), the new model of Precipitation Estimation based on IR data with Spherical Convolutional Neural Network (PEISCNN) was first trained, tested and validated. Compared to the commonly used IR-based precipitation product PERSIANN CCS (the Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Network, Cloud Classification System), PEISCNN showed significant improvement in the metrics of POD, CSI, RMSE and CC, especially in the dry region and for extreme rainfall events. The PEISCNN model may provide a promising way to produce an improved IR-based precipitation product to benefit a wide range of hydrological applications.
Performance assessment of groundwater level forecasting with deep learning: a case study of Lower Saxony, Germany.
Authors: Gomez Mariana , Noelscher Maximilian , Broda Stefan , Hartmann Andreas
Published: February 2023

Groundwater level forecasting with machine learning has been widely studied due to its generally accurate results and little input data requirements. Furthermore, machine learning models for this purpose are set up and trained in a short time when compared to the effort required for process-based, numerical models. Despite the high performance of models obtained at specific locations, applying the same model architecture to multiple sites across a regional area might lead to contrasting accuracies. Likely causalities of this discrepancy in model performance have been barely examined in previous studies. Here, we investigate the link between model performance and the effects of geospatial site characteristics and time series features. Using precipitation and temperature as predictors, we model groundwater levels at approximately 500 observation wells in Lower Saxony, Germany, using a 1-D convolutional neural network with a fixed architecture and hyperparameters tuned for each time series individually. The performances are evaluated against geospatial and time series features using correlation coefficients. Model performance is negatively influenced at sites near waterworks and densely vegetated areas. Besides, the more complex the time series, the higher the metrics, but autocorrelation reduces the model performance. The new insights evidence that further information is required at certain locations to improve model accuracy due to external impacts.  
Impact of Climate Change on Non-stationarity of Extreme Streamflows in Godavari River Basin, India
Authors: Rishika Ananthula , Reghunath Gowri , P. Mujumdar Pradeep
Published: February 2023

The frequency analysis and risk assessment of extreme precipitation and streamflow at basin scales are essential for effective hydrologic design and water resource management activities. Processes that generate streamflow are influenced by both catchment characteristics and environmental conditions. As a result of climate change, human-induced changes in land use patterns (urbanization, deforestation, encroachment of flood plains), and faulty reservoir operations, the stationarity of streamflow assumption is questionable in flood frequency analysis. The changing climate has continued to alter the intensity, duration, and frequency of extreme events in the region, and the current status of climate change impacts on hydrology calls for the evaluation of a non-stationarity approach for extremes to enhance effective planning. This study aims to investigate the non-stationarity of streamflow and hydrologic sensitivity of catchments of the Godavari River basin located in peninsular India to changing climatic circumstances using a multi-model ensemble based on CMIP6 climate models. Firstly, Mann Kendall (MK) test is performed to detect the presence of temporal trends in the observed annual maximum streamflow series at 14 gauging stations distributed across the basin. Then peak flow series are analyzed using stationary and non-stationary models assuming invariant shape parameters and linear functions as location and scale parameters with time as a covariate. A generalized extreme value (GEV) distribution coupled with downscaled climate projections is employed to assess the probability distribution of extreme events. Results show that only 2 out of 14 streamflow series show temporal trends, suggesting that using physically based covariates instead of time can provide a better fitting. The return period can be shortened by more than one-tenth of its length, and flood risk is projected to increase significantly between the historical and future periods. These findings provide insights into non-stationary extreme streamflow behaviour, emphasizing the importance of identifying dominant drivers for changes in flooding under climate change.
Impacts of climate variability and change on regional fire weather in heterogeneous landscapes of Central Europe
Authors: Miller Julia , Böhnisch Andrea , Ludwig Ralf , Brunner Manuela
Published: February 2023

Wildfires have reached an unprecedented scale in recent fire seasons of the Northern Hemisphere as demonstrated by the summers of 2021 and 2022. Severe fire seasons, characterized by heat, drought and windy conditions, might become even more frequent and will extend to more temperate regions in northern latitudes under global warming. Still, quantifying the effects of climate change on future fire danger is challenging because natural variability hides trends of increasing fire danger in climate model simulations in future potentially fire-prone areas. Single Model Initial-Condition Large Ensembles (SMILEs) help scientists to distinguish climate trends from natural variability. Here, we leverage the capabilities of SMILEs to assess future changes in fire weather conditions in a currently non-fire-prone area in Central Europe. The study area covers four heterogeneous landscapes, namely the Alps, the Alpine Foreland (southern parts), the lowlands of the Southern German Escarpment, and the eastern mountain ranges of the Bavarian Forest (northern parts). We use a SMILE of the Canadian regional climate model version 5 (CRCM5-LE) under the RCP 8.5 scenario from 1980 to 2099 to analyze trends in fire danger quantified by the globally applicable Canadian Fire Weather Index (FWI).Our results show the strongest increases for the median (50th percentile) and extreme (90th percentile) FWI in the northern parts of the study area during the late summer months July, August and September. The southern, more alpine parts are affected less strongly and show high fire danger mostly in August by the end of the 21st century for the median FWI. Over the whole study area, we find that the extreme FWI in the present climate period will become much more frequent at the end of the century. In the South German Escarpment and Eastern Mountain Ranges, the climate change trend exceeds natural variability in the late 2040’s. Due to weaker variability, the time of emergence is reached in the Alps and Alpine Foreland in the early 2040's.These results demonstrate that the CRCM5-LE is a suitable dataset to disentangle climate trends from natural variability in a multivariate fire danger metric. Our study emphasizes that regions with a low fire danger under current climate conditions will experience weather conditions facilitating the development of potentially uncontrollable wildfires in a warming climate.
Deformable plate reconstructions of Atlantic Canada and its conjugates back to the Paleozoic
Authors: King Michael , Welford J. Kim , Waldron John
Published: February 2023

Atlantic Canada and its conjugate margins, the Irish, Iberian, and Moroccan margins, were subject to rifting and eventual breakup during the Mesozoic, following prior Appalachian Orogenesis from the early to mid-Paleozoic. The complexities of that older orogenesis, involving accretion and collision of Laurentian and peri-Gondwanan terranes during the closing of the Iapetus Ocean, contributed to the heterogeneous pre-rift template of the modern southern North Atlantic Ocean and the timing and extent of subsequent rift-related deformation. In this work, we present newly-derived offshore and onshore present-day crustal thickness estimates of Atlantic Canada that are calculated using constrained 3-D gravity inversion and later reconstructed back to the onset of rifting and beyond, using GPlates and pyGPlates. In addition, deformable plate reconstructions are also used to reconstruct present-day magnetic anomalies, both onshore and offshore, back through time to track Appalachian orogenic trends beyond what can be deduced from geological field mapping alone. With the pre-rift template of the southern North Atlantic Ocean restored, we then attempt to extend these reconstructions further back in time to the Paleozoic to investigate strain localization within and between Appalachian terranes. Our results clearly reveal the fundamental influence of orogenic inheritance on subsequent rift events and the present-day variations in the crustal architecture that are observed along rifted margins. This study also provides the first quantitative assessment of Atlantic Canada’s crustal evolution from a compressive regime, to an extensional regime, to passive margin development.
Combining the time-lapse amino-mapping and zymography to co-localize spatial distribution of organic N with enzymatic activity in the rhizosphere
Authors: Shen Guoting , Guber Andrey , Khosrozadeh Sajedeh , Ghaderi Negar , Blagodatskaya Evgenia
Published: February 2023

As N limitation strongly influences ecosystem functioning, numerous studies explored the transformation process of mineral nitrogen. In contrast, the importance of organic nitrogen, which can short-circuit the mineralization step, for plant nutrition in different ecosystems often overlooked. A spatial link between the sources of organic N and N-acquiring enzymatic activity in soil is still missing due to the lack of suitable techniques. Here we developed a novel approach: in situ amino-mapping and coupled it with time-lapse zymography to quantify distribution of organic nitrogen in the rhizosphere of Zea mays L and tested spatial association of enzymatic activity with organic nitrogen abundance at the root-soil interface. Coupling the two approaches enabled identification the hotspots of amino-N, and revealed their co-occurrence with N-related enzymatic activity in seminal roots and root tips: intensive enzymatic activity was accompanied by large amino-N content, especially in the rhizosphere of seminal root tips. This work was conducted within the framework of the Priority program 2089 “Rhizosphere spatiotemporal organization – a key to rhizosphere functions”, funded by German Research Foundation (DFG – Project number: 403664478). Seeds of the maize were provided by Caroline Marcon and Frank Hochholdinger (University of Bonn).