bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of snow line altitude on subglacial sediment export
Authors: Jenkin Matt , Mancini Davide , Dietze Michael , Miesen Floreana M. , Lane Stuart N.
Published: February 2023

Large Alpine glaciers typically export significant quantities of subglacially eroded sediment to their downstream environments via meltwater streams. The supply of this glaciogenically-produced sediment has an extensive impact on landform genesis and evolution; downstream ecology and ecosystem succession; river morphology and flood risk management; hydropower installations and industrial sediment extraction. However, little is known about the processes and mechanisms driving the entrainment and evacuation of subglacial sediment by meltwater flow. Controls on the rate of sediment export remain poorly constrained, limiting the reliability of future sediment yield predictions. Although the fine (suspended) fraction of meltwater-borne subglacial sediment export is relatively well studied, records of suspended sediment load are commonly obtained from distal proglacial locations and may consequently be affected by filtering effects in proglacial rivers and forefields. Additionally, almost nothing is known about the coarse (bedload) component and its relationship to suspended sediment transport due to the difficulties in monitoring bedload flux. In this study, we present a first-of-its-kind dataset from Glacier d’Otemma, Switzerland, capturing three years (2020, 2021 and 2022) of continuous suspended sediment load, bedload and water discharge data from a monitoring site immediately in front of the glacier meltwater portal. Measurements of coarse sediment flux were performed using recently developed environmental seismological monitoring techniques. Data from all three years show that bedload delivery to the glacier margin switches from being transport-limited to being supply-limited during the melt season and was driven by snow-line retreat. Bedload evacuation reduces to very low levels as soon as the snow-line reaches the upper parts of the glacier, which it does increasingly often due to climate warming. We hypothesise that the position of the snow line controls the degree of channelisation – or the efficiency – of the subglacial drainage network above and below it, with consequences for both sediment availability and channel competence. Meltwater in the non-channelised parts of the glacier struggles to transport bedload. As the channelisation develops, accumulated bedload is evacuated until the point at which the subglacial channel network reaches its maximum extent or, due to progressive channel division in a dendritic network, is developing channels that are too small to readily transport it. Thus, recent reports of increases in bedload yield from Alpine glaciers may not reflect increases in glacial erosion but simply an increase in the upstream elevation of snow-lines, the associated subglacial channelization and hence subglacial bedload export capacity.
Similarity of long-term temporal decrease in atmospheric Cs-137 between Chernobyl and Fukushima
Authors: Akasaki Kentaro , Mori Shu , Suetomi Eiichi , Hatano Yuko
Published: February 2023

We compare the atmospheric concentrations of Cs-137 after a decade between Chernobyl and Fukushima cases. We plotted 8 datasets on log-log axes (5 cases in Chernobyl and 3 cases Fukushima) and found that they appear to follow a single function.There have been measured the atmospheric concentration after the Chernobyl accident for more than 30 years [1]. On the other hand, several teams of Japanese researchers have been measured in Fukushima and its vicinity for almost 10 years. [2][3] In this study, we compare 5 sites in Chernobyl (Pripyat, Chernobyl, Baryshevka, Kiev, and Polesskoe) and 3 sites in Fukushima (FDNPP O-6 and O-7, Univ. Fukushima).We adjust the magnitude of the data because it depends on the amount of the initial deposition. After the adjustment, we plot the 8 cases on a log-log plot. We found that the 8 cases collapse together, with the power index of -1.6. Namely,C(t) ~ t^{-1.6}.               …(1)Incidentally, we have been proposed a formula which reproduce the long-term behavior of atmospheric concentration at a fixed location asC(t) = A exp(-bt) t^{-4/3}    …(2)where A is a parameter which relates to the amount of the initial deposition and b as the reaction rate of all the first-order reactions (including the radioactive decay rate, the vegetation uptake rate, the runoff rate, etc). We will investigate the difference in the power-law index in Eq. (1) and (2). The parameter b is highly dependent on the environment. When we take a proper value of b, the apparent decrease of the concentration will change from t^{-4/3}. We may make the apparent power-index close to -1.6. [1] E. K. Garger, et al., J. Env. Radioact., 110 (2012) 53-58.[2] A. Watanabe, et al., Atmos. Chem. Phys. 22 (2022) 675-692.[3] T. Abe, K. Yoshimura, Y. Sanada, Aerosol and Air Quality Research, 21 (2021) 200636.
Ecosystem services derived from SGD: a perspective from traditional and academic knowledge in Mediterranean societies
Authors: Alorda-Kleinglass Aaron , Ruiz-Mallen Isabel , Rodellas Valentí , Rossi Sergio , Belmonte Genuario , Diego-Feliu Marc , Garcia-Orellana Jordi
Published: February 2023

Submarine Groundwater Discharge (SGD) is recognized as a fundamental hydrological process that supports many coastal biogeochemical cycles and social-ecological systems. However, very little has been investigated about how SGD affects society and human well-being. Coastal services provided by ecosystems dependent on SGD can be analyzed and clustered into the four main categories of Ecosystem Services (i.e., Provisioning, Supporting, Regulating and Cultural), which are divided into subcategories defined as outcomes. This enables identifying and discussing both benefits and threats to coastal societies resulting from SGD outcomes. Due to the lack of academic literature on this matter, here we explore the academic and local knowledge of the social perception toward SGD and its ecosystem services (ES). This research is conducted through two case studies, the island of Mallorca and the Region of Salento, to unravel the similarities and particularities of each Mediterranean society regarding the SGD-ES identified and their historical evolution. Such evolution transitions from the management of the fresh groundwaters for human consumption to the exploitation by the tourism industry of cultural ecosystem services related to the same discharge. Our review also shows how compiling different search possibilities (e.g., local languages, including paper-based documents; grey literature; local knowledge; academic literature) has resulted in a significant increase in the reported ES and its understanding. In this direction, combing traditional and academic knowledge are key to accessing society's perception of most cultural ES. Therefore, SGD-ES studies are extremely locally-dependent, and thus regional or global require an in-depth understanding of all areas comprehended in the study. Overall, the research presented in this study contributes to a better understanding of the complexity of the SGD and its social implications. Therefore, this research presents to the academic community new insights from traditional knowledge and an opportunity to integrate multidisciplinarity into a study subject that has usually only been looked from the prism of natural sciences.
Tectonic stress changes related to plate spreading prior to the 2021 Fagradalsfjall eruption in SW Iceland
Authors: Hrubcová Pavla , Vavryčuk Václav
Published: February 2023

The Reykjanes Peninsula in SW Iceland is a part of the Mid-Atlantic plate boundary. It forms its transtensional segment with several volcanic and faulting systems. We focus on the 2017 seismicity that occurred in the central part of Reykjanes at the place of Fagradalsfjall volcano prior to its eruption on March 19, 2021. We invert well-determined focal mechanisms of the 2017 seismicity and provide mapping of tectonic stress in space and time. Our results disclose heterogeneous stress field manifested by mix of shear, tensile and compressive fracturing.  Although the fracturing was diverse, directions of the principal stress axes were stable and consistent with the processes at the transtensional divergent plate boundary. The prominent stress direction was in the azimuth of 120°±8°, which represents the overall extension related to rifting in the Reykjanes Peninsula. The activity initiated on the transform fault segment with predominantly shear strike-slip events. The non-shear fractures occurred later being associated with normal dip-slips and corresponding to the opening of volcanic fissures trending in the azimuth of 30-35°, perpendicular to the extension. The dip-slips were mainly located above an aseismic dike detected in the centre of the 2017 swarm. This dike represents a zone of crustal weakening during a preparatory phase of future 2021 Fagradalsfjall volcanic eruption located at the same place. Moreover, we detected local variation of stress when the stress axes abruptly interchanged their directions in the individual stress domains. These stress changes are interpreted in a consequence of plate spreading and upcoming fluid flow during a preparatory phase of a rifting episode.
Modelling Europa’s collisional atmosphere using the DSMC method
Authors: Schlarmann Leander , Vorburger Audrey , Carberry Mogan Shane R. , Wurz Peter
Published: February 2023

In this study, we present preliminary results of modelling the potentially collisional atmosphere of the Jovian satellite Europa using the Direct Simulation Monte Carlo (DSMC) method [1]. In the DSMC method particular gas flows are calculated through the collision mechanics of representative atoms or molecules that are subject to binary collisions to simulate macroscopic gas dynamics.NASA's Europa Clipper mission [2] and ESA's JUpiter Icy Moons Explorer (JUICE) [3] will encounter Europa with flybys in the 2030s to sample the atmosphere of the icy moon using mass spectroscopy. Measurements with the MAss Spectrometer for Planetary EXploration (MASPEX) onboard Europa Clipper and the Neutral gas and Ion Mass spectrometer (NIM) onboard JUICE will determine the composition of Europa's exosphere and, potentially, sample the plume material. From the exosphere measurements, the chemical composition of Europa's surface could be derived, whereas plume measurements would potentially allow conclusions about the chemical conditions of Europa's subsurface ocean.Models of the collision-less exosphere for the icy moon [4, 5] have shown that Europa’s ice-sputtered atmosphere is dominated by O2 near the surface with an extended H2 corona at higher altitudes. Here, we compare the results of these studies with the DSMC model including deeper layers of Europa's collisional atmosphere.[1] Bird, G. A. (1994). Molecular gas dynamics and the direct simulation of gas flows.[2] Phillips, C. B., and Pappalardo, R. T. (2014). Eos, Transactions AGU, 95(20), 165-167.[3] Grasset, O., et al. (2013). Planetary and Space Science, 78, 1-21.[4] Vorburger, A., and Wurz, P. (2018). Icarus, 311, 135-145.[5] Vorburger, A., and Wurz, P. (2021). J. Geophys. Res. Space Phys., 126(9), e2021JA029690.
Future soil erosion of shifting cultivation on hillslopes – modeling interactions between slope steepness, fallow periods, and climate change
Authors: Schröder Lea Sophia , Rasche Livia , Jantke Kerstin , Mishra Gaurav , Lange Stefan , Schneider Uwe A.
Published: February 2023

Shifting cultivation, also known as slash-and-burn agriculture, on steep terrain has been criticized for causing high rates of soil erosion thus promoting land degradation in South and Southeast Asia. Particularly, short fallow periods resulting from increasing land pressure are suspected of accelerating degradation processes. In addition, the rising frequency of high-intensity precipitation events associated with climate change can be expected to further increase the pressure on shifting cultivation. However, abandonment of shifting cultivation has turned out to be hardly feasible or desirable, particularly, where it provides food security and cultural identity to the tribal population, as is the case in Northeast India. This raises the question how increasing pressure from reduced fallow periods and climate change will affect future soil erosion of uphill shifting cultivation systems. As measured data on these interactions are not available, we applied a modeling approach to identify trends in soil erosion for different slope inclinations, fallow periods, and climate change scenarios. We used the Environmental Policy Integrated Climate (EPIC) Model to simulate daily soil loss for three different climate scenarios (SSP126, SSP370, SSP585) derived from five climate models for the near (2021-2050) and far (2071-2100) future. Simulations were carried out for six collected soil profiles, short, medium, and long fallow periods, and slope inclinations up to 70 %. Our results indicate a negative, non-linear relationship between the length of the fallow period and erosion, with soil loss being more than twice as high for systems with a 10-year compared to a one-year fallow regime. Further, our research demonstrates that long fallow periods can compensate, to a limited extent, for steep slopes. However, climate change, particularly under the medium-high (SSP370) and high-end (SSP585) emission scenarios, will lead to substantial increases in erosion by a factor of 2.2 and 3.1, respectively, towards the end of the century, thus reducing the possibility space for sustainable shifting cultivation.
Using GNSS-IR and the ARIMA Model to Forecast Changes in Glacier Surface Elevation: A Case Study
Authors: Radha Krishnan Sree Ram , Suresh Simran
Published: February 2023

Surface elevation changes are variations in the height of the Earth's surface that occur in both spatial and temporal scales, either horizontally or vertically. These movements can be caused by a variety of causes, including tectonic activity, and glacier movement. Understanding and forecasting surface elevation changes are critical for mitigating and adapting to their consequences. We provide a novel method for investigating surface elevation fluctuations by employing the GNSS-IR technique and the ARIMA model for predicting variations in surface elevation.The  GNSS-IR (Global Navigation satellite system- interferometric reflectometry) technology estimates the distance between two locations using satellite signals and interferometry, and the difference between the two sites represents the surface elevation change. ARIMA model is a specialized statistical combination of an auto-regressive integrating model with a moving average that is designed to analyze data and make predictions about changes in the surface level of the glaciers. By combining these methods, we are able to gain a more comprehensive understanding of the processes driving the changes in the ice sheet and the potential impacts of these changes on sea levels. This approach can also be used for other locations.Over an eight-year period (2010-2019), four GPS sites installed at significantly retreating glacier locations in Greenland are chosen for the study. The interferometric reflectometry signals' SNR measurements provide a better understanding of GPS's vertical displacement, which allows the reflector height to be inferred. This observable is predicted by the ARIMA model for the duration from 2020 to the present. The forecasted values and the dataset from the multi-mission altimetry are compared. Between the actual elevations and the values that our model predicted, we were able to achieve an RMSE of 0.54, 1.2, 0.77 and 0.62 cm for the four GPS sites.The Greenland Ice sheet is losing mass at an alarming rate, according to our findings, which highlights the importance of the ongoing research into the drivers underlying ice and glacier mass balance and the need for proactive measures to mitigate their effects on the global ecosystem.
Occurrence of multilayer clouds and ice-crystal seeding during the Arctic Ocean 2018 and MOSAiC research campaign
Authors: Achtert Peggy , Tesche Matthias , Wallentin Gabriella , Hoose Corinna
Published: February 2023

Previous research on arctic clouds has focused on single-layer clouds. However, the occurrence of multi-layer clouds in the Arctic is of importance, since in such systems upper clouds can influence the phase of lower clouds. This is the case when ice crystals fall from above into supercooled liquid water clouds and trigger the formation of mixed-phase clouds.The aim of our project is to investigate the occurrence of multi-layer clouds and seeding using the combination of radiosonde and cloud radar observations. The focus is on the MOSAiC campaign. In order to classify and interpret the results, previous measurements will be used as well.During the Arctic Ocean 2018 campaign multi-layer clouds were observed 56% of the time and 48 % showed a likelihood of seeding. Previous satellite studies on multi-layer-clouds showed an occurrence of 11 %. During the MOSAiC campaign multi-layer clouds occurred around 50 % of the time and showed a latitude dependency, with more multi-layer clouds north of 84°N.
An agent-based model of shared irrigation resources using the Theory of Planned Behaviour in arid and semi regions
Authors: El-Fartassi Imane , Milne Alice E. , El Alami Rafiq , Metcalfe Helen , Alonso-Chavez Vasthi , Waine Toby W. , Zawadzka Joanna , Diarra Alhousseine , Corstanje Ron
Published: February 2023

The expansion of irrigated agriculture and recurrent drought periods poses a serious threat to the renewability and sustainability of common water resources in arid and semi-arid regions. These shared resources can take the form of dam water which is shared between farmers according to a predefined schedule or groundwater which the farmers independently extract. The dam water is less expensive to use but this source can be limited in drought years risking crop productivity. Groundwater is a more reliable resource but is more expensive to extract and can cause soil salinity. Simulating agricultural management systems requires understanding and quantifying how biophysical and socio-economical constraints influence the decisions of farmers. Therefore, this research aimed to develop an agent-based modelling (ABM) approach to simulate farmer behaviour in irrigation management. The Theory of Planned Behaviour was used as a theoretical framework to simulate decision models that were integrated with a biophysical model describing the interaction of farmers with water resources and how limitations of water resources and salinity impact crop yield. Through modelling, we explore various strategies to improve sustainable water use. The methodology is applied to an irrigated perimeter of Al Haouz Basin, Morocco, as a case study, where there are different stakeholders and water user associations with conflicting objectives. The ABMs were parameterised using data collected by surveying 70 farmers. The findings indicate that the existing irrigation scheduling was usually satisfactory. However, with the exacerbation of drought periods, the use of dam water resources is unreliable. Farmers responded by seeking alternative water resources and changing their irrigation systems and cropping patterns which led to the potential of overexploitation of groundwater and increased accumulated salt content.
Geologic records of moderate-to-large pre-historical earthquakes in South Korea
Authors: Choi Jin-Hyuck , Ryoo Chung-Ryul , Lee Tae-Ho , Cheon Youngbeom , Lee Hoil , Kim Taehyung , Choi Yire , Kim Chang-Min
Published: February 2023

South Korea, one of the most densely populated areas, has been considered a tectonically safe region as there were no destructive earthquakes in modern society. Indeed, there is no report of any earthquake event with surface ruptures in a historical period. After the 2016 Mw 5.5 Gyeongju earthquake, the largest instrumentally recorded event in South Korea, the need for research on large-earthquakes has highlighted and multidisciplinary research projects were conducted for paleoseismological investigations. Here we introduce the newly discovered geologic records of pre-historical large-earthquakes. Firstly, paleoearthquake surface ruptures were newly identified along the entire section of the Yangsan Fault, one of the most major strike-slip structures in the Korean Peninsula. For a 50-km-long fault section, a fault theme map with a scale of 1:25,000 was produced and paleo-earthquake records were found at multiple sites mainly based on excavation surveys. The results provide an opportunity to interpret the temporal and spatial scenarios of the paleo-earthquakes along the fault. Secondly, stratigraphic records of paleo-earthquake surface rupture were found at a few localities near another major strike-slip fault system; the Gongju Fault System, and we obtained paleoseismic data. These records imply that moderate-sized earthquakes often occurred on minor faults, not on the main trace of the major faults. Our results indicate that the crustal deformation of the Korean Peninsula, which belongs to the very slow-deforming regions, is accommodated by moderate-to-large earthquakes with a recurrence time ranging from thousands to tens of thousands of years. Considering that it is not easy to detect any crustal deformations using micro seismicity and/or geodetic data due to too slow deformation, we note that it is necessary to obtain more paleoseismological data to well understand tectonic deformations as well as to assess hazards associated with future earthquakes.
Shallow Geothermal Energy systems for micro-scale 5G DHC in the Mediterranean island of Cyprus
Authors: Aresti Lazaros , Makarounas Christos , Florides Georgios , Onoufriou Toula , Christodoulides Paul
Published: February 2023

Shallow Geothermal Energy (SGE) systems find application through the use of Ground Source Heat Pumps (GSHPs) for space heating and cooling. GSHPs provide a higher performance over the alternative conventional Air Source Heat Pump (ASHP) systems, and have seen an increased interest with the continuous energy price increase and the need for lowering the CO2 emissions to meet the European Union “Fit for 55” targets. The high initial capital required for the GSHP systems in the residential sector is the main preventive factor for the GSHP systems. Recent studies revealed that with the nearly Zero Energy Buildings (nZEB) EU derivative in effect, the residential dwellings are built with a higher insulation on the building’s envelop and therefore with a lower heating and cooling demand; hence the potential payback period of such systems is increased.Geothermal energy District Heating (DH) on the other hand could make these systems more viable with the advantage of lower carbon emissions, lower maintenance and a lower cost, but at the moment the infrastructure and availability are mainly present in central and northern Europe, where a higher heating demand is required compared to the southern EU. Having a central unit for distribution however, requires a large plant area, and of course the need for infrastructure and insulated pipes. An alternative to these solutions could be the use of SGE systems at a micro scale level.To this extent, this research aims to computationally investigate the possibility and potential of SGE systems for a micro-scale urban environment. A theoretical case study is developed, with the inclusion of residential blocks categorized as “islands” for the production, use and distribution of SGE as a form of 5th generation (5G) DH and Cooling (DHC) with Mediterranean climate in the island of Cyprus. The case study includes either multiple multi-story residential buildings with nZEB characteristics or multiple detached residential buildings within a residential block, typical for the island of Cyprus. The heating and cooling demands, as well as the peak loads are estimated and the Ground Loop Design (GLD) software is used to size the required vertical Ground Heat Exchangers (GHEs) with different configurations. The effect of the unbalanced ground temperature and the temperature gain/ loss from the heat distribution is examined with the use of COMSOL Multiphysics software. Results indicate a potential advantage of the use of GSHP systems at a residential use micro-scale in terms of costs reduction and promotion of the geothermal energy use.
The role of rainfall infiltration on landslide occurrence at regional scale
Authors: Abancó Clàudia , Asurza Flavio Alexander , Hürlimann Marcel , Medina Vicente , Bennett Georgina
Published: February 2023

The rain that falls during or after rainy periods is one of the major triggers for landslides. It is crucial to account for the infiltration not only on the time of landslide occurrence but also days/weeks/months in advance, especially in areas with high amounts of antecedent and triggering rainfall such as in tropical climates.We used a physically-based model called “Fast Shallow Landslide Assessment Model” (FSLAM) (Medina et al., 2021) to map landslide susceptibility in the area of Itogon (Benguet, Philippines), often affected by Multiple-Occurrence Regional Landslide Events (MORLEs, Crozier, 2005). The model uses a simplified hydrological model and the infinite slope theory. The main input data are soil properties, vegetation, terrain elevation and rainfall maps.We analysed changes in landslide susceptibility between two very intense rainfalls that did not trigger MORLE and Typhoon Mangkhut (2018) that did trigger a MORLE in the area.  The results show that two main parameters control the instability of the slopes are: water recharge below the top soil layer before the event and the available pores volume (fillable porosity) in the soil at the time of the event. When the fillable porosity in the soil was lower, the landslide susceptibility increased and it was more likely to trigger a MORLE (case of Typhoon Mangkhut, 2018). On the contrary, if the soil had more fillable porosity (less saturated), the probability of MORLE occurrence is lower, no matter how high the rainfall intensity during the event is.The findings of this work highlight that new approaches to develop hydro-meteorological thresholds for landslide early warning purposes should be evaluated, especially in tropical regions.   Crozier, M.J. Multiple-occurrence regional landslide events in New Zealand: Hazardmanagement issues. Landslides 2, 247–256 (2005). https://doi.org/10.1007/s10346-005-0019-7Medina, V.;  Hürlimann, M.; Guo, Z.; Lloret, A.; Vaunat, J.; Fast physically-based model for rainfall-induced landslide susceptibility assessment at regional scale, CATENA, 201, 105213 (2021), https://doi.org/10.1016/j.catena.2021.105213.
Spatial and temporal patterns of tropical forest microclimate in Mount Kenya
Authors: Jia Jinlin , Hughes Alice C. , Santos Erone Ghizoni , Pellikka Petri K.E. , Maeda Eduardo Eiji
Published: February 2023

Tropical-mountane forests are global biodiversity hotspots, and also play important roles in regional hydrological systems. Yet, climate and especially microclimate in these areas, and how they vary spatially and temporally have been largely neglected. Due to the buffering effect of vegetation, microclimate (i.e. environmental conditions experienced by organisms inside the forest) can be substantially different from the conditions outside the forests. Additionally, sparse meteorological stations and satellite data cannot provide accurate climate estimates over tropical mountains, especially on microclimate under the canopy. Consequently, further research is needed to clarify the spatial and temporal patterns of environmental conditions in these regions.In this study, we set 16 microclimate sensors on the southern and southeastern slopes of Mount Kenya, with an elevation range of 720 m (from 1730 m a.s.l. to 2450 m a.s.l) across the Lower Montane Wet Forest. The sensors measured understory air temperature and soil moisture every 15-minutes across a 2-year period.We found that average soil moisture in the study area varied with monthly precipitation, synchronously increasing with the start of the rainy seasons, but decreasing with a approximate one month lag towards the dry seasons. Soil moisture did not have a linear relationship with altitude, presenting a local minimum at about 2050 m a.s.l.. The understory air temperature changed linearly with altitude, whereas the lapse rate varied across seasons. The seasonal variation of diurnal lapse rate was about three times larger than that during the night. For the intra-daily temperature, minimums occured simultaneouly (at 4:30 am) independently of altitude. Conversely, at higher altitudes, the maximum temperature occurred earlier. The lowest average daily temperature and smallest daily temperature range occurred between June and August, whilst the opposite phenomena occurred from January to March. Furthermore, Jan-Feb-Mar also presented the smallest lapse rate and low soil moisture, representing the main period of vegetation growth. Our results will contribute for clarifying the conditions sustaining the disproportionally high biodiversity and biomass observed in tropical mountain forests. Further research will investigate the drivers and biophysical feedbacks of microclimate, as well as their sensitivity to climate change.
Design flood estimation for ungauged catchments in Krishna River Basin using a transformation-based approach to Regional Flood Frequency Analysis
Authors: Singh Amit , Chavan Sagar
Published: February 2023

Estimation of flood quantiles at ungauged sites is a vital aspect of the design and planning of hydraulic structures. There are various approaches such as Conventional Index Flood (CIF), Logarithmic Index Flood (LIF), and Population Index Flood (PIF), etc, that have been established to evaluate flood quantile at ungauged sites. These conventional approaches assume that the scale and shape parameters of frequency distributions remain identical for all the sites in a homogeneous region. However, this assumption may not be valid for hydrologically similar real-world catchments. Recently, a transformation-based mathematical approach to regional frequency analysis was proposed by Basu and Srinivas (2013), which ensured the assumption of having identical scale and shape parameters across the sites in a hydrologically similar homogeneous region. The approach involves (i) identification of appropriate frequency distribution representing the homogeneous region, (ii) Mapping the flood quantile (corresponding to various non-exceedance probability) from the original space to a dimensionless space, where values of parameters of distributions at sites in the region remain identical, (iii) construction of regional growth curve in dimensionless space and, (iv) Mapping of dimensionless regional growth curve to original space by applying inverse transformation equations. This study presents an application of the approach given by Basu and Srinivas (2013) for estimating the design flood estimate at ungauged catchments in the Krishna river basin. The delineation of hydrologically similar regions is performed by using a global k-means clustering algorithm. In this study, The parameters of the inverse transformation equations are obtained by using log-linear regression model (LLRM), generalized additive model (GAM), and multivariates adaptive regression spline (MARS). Finally, a comparative analysis is performed to assess the efficacy of the regression models in estimating the parameters of transformation equations. The result revealed that the Regional Flood Frequency Analysis (RFFA) using Basu and Srinivas's (2013) approach is effective for reliable prediction of design flood estimates in Indian watersheds.
Merging clouds retrieved from ALADIN/Aeolus and CALIOP/CALIPSO spaceborne lidars
Authors: Feofilov Artem , Chepfer Hélène , Noël Vincent
Published: February 2023

Clouds play an important role for the energy budget of Earth. But, when it comes to predicting the climate's future, their behavior in response to climate change is a major source of uncertainty. To understand and accurately predict the Earth's energy budget and climate, it is necessary to have a thorough understanding of the cloud variability, including their vertical distribution and optical properties.Satellite observations have been able to provide ongoing monitoring of clouds all around the globe. Among them, active sounders hold a special place thanks to their capability of measuring the vertical position of the cloud with an accuracy of about 100 meters and with a typical horizontal sampling on the order of hundreds of meters. However, clouds retrieved from two spaceborne lidars are different, because the instruments use different wavelengths, pulse energies, pulse repetition frequencies, telescopes, and detectors. In addition, they do not overpass the atmosphere at the same local time.In this work, we discuss the approach to merging the clouds retrieved from the space-borne lidar ALADIN/Aeolus, which has been orbiting the Earth since August 2018 and operating at 355nm wavelength with the clouds measured since 2006 by CALIPSO lidar, which operates at 532nm.We demonstrate how to compensate for the existing instrumental differences to get an almost comparable cloud dataset and we discuss the importance of the aforementioned differences between the instruments. The method developed in this study sets the path for adding future lidars (e.g. ATLID/EarthCare) to the global climate lidar cloud record.
Nitrous oxide emissions and ammonia volatilisation in a field experiment with different organic and inorganic fertilisers with biochar combinations
Authors: Hartmann Ferdinand , Fernandez Balado Celia , Hood-Nowotny Rebecca
Published: February 2023

Agriculture is contributing majorly to anthropogenic greenhouse gas emissions and pollution. The application of nitrogen fertilizers increases N2O emissions and NH3 volatilisation. Nitrous oxide (N2O) is a highly potent greenhouse gas and ammonia (NH3) can re-react with soil and forms N2O or can lead to other environmental issues in the surrounding. Further, to keep economic (fertiliser prizes drastically increased due to the energy crisis) and ecological (Haber Bosch process is very energy intense and still based on fossil fuels) costs for fertiliser low, a high fertilizer use efficiency is worthwhile. Therefore, advances in agricultural practices reducing atmospheric N-losses are highly relevant in order to mitigate global warming and related environmental issues. Biochar can reduce N2O emissions and NH3 volatilisation by influencing various soil properties. However, this depends on pedoclimatic conditions, the applied biochar, and other agricultural practises. To refine biochar’s use to mitigate atmospheric N-losses more data for different soils and fertilizers are needed, especially from experiments coming close to common agricultural settings. In a field experiment we cultivated corn (Zea mays) with different organic (external organic matter, EOM) and inorganic fertilizers with and without biochar combinations. The original soil was loamy, low in organic carbon and slightly acidic. Our results are showing significant and substantial reductions in N2O emissions and NH3 volatilisation within the first weeks after fertiliser application. This pattern was especially observed for synthetic fertiliser. We suggest that biochar is a suitable amendment for fertilisation, especially for highly productive agroecosystems where high amounts of fertiliser are needed, to reduce environmental impact and increase fertiliser use efficiency.
A regional gravimetric geoid model in support of the GeoNetGNSS CORS network
Authors: Vergos Georgios S. , Natsiopoulos Dimitrios A. , Tzanou Eleni A. , Mamagiannou Elisavet G. , Triantafyllou Anastasia I. , Tziavos Ilias N. , Ramnalis Dimitrios , Polychronos Vassilios
Published: February 2023

Within the GeoNetGNSS project, funded by the European Union and National Funds through the Region of Central Macedonia (RCM), the main goal is to establish a dense network of Continuously Operating Reference Stations (CORS) in Northern Greece. Accuracy, reliability, wide coverage, ease of use and cost effectiveness are among the main advantages of differential positioning supporting mapping, surveying, geodetic, and large infrastructure projects. However, as ellipsoidal heights from GNSS measurements have no physical meaning, they should be transformed to orthometric heights. This transformation requires an accurate gravimetric geoid model to be readily available, in order to carry-out the so-called GNSS/Leveling, i.e., the determination of orthometric heights without the need to carry out levelling. With that in mind, a regional gravimetric geoid was determined based on historical and newly acquired high-accuracy and density gravity data that have been collected through dedicated gravity campaigns. These were focused not only around the CORS stations but also targeted the entire area of RCM. The gravity observations have been carried out with the CG5 gravity meter relative to absolute gravity stations established using the A10 (#027) absolute gravity meter. The development of the geoid was based in the classical Remove-Compute-Restore (RCR) technique and an FFT-evaluation of Stokes’ integral. The long and short wavelengths of the gravity field spectrum were removed from the available input gravity data, then prediction of the residual geoid was carried out and finally the effects removed have been restored to derive the final model. To model the long-wavelength part of the spectrum, XGM2019e has been used as reference while the topographic effects were evaluated based on a spherical harmonics expansion of the Earth’s potential and ultra-high resolution residual terrain correction (RTC) effects from a global model. The prediction of the geoid model was carried out using the classical 1d-FFT spherical Stokes convolution with the Wong-Gore modification for the Stokes kernel and 100% zero-padding in all directions. Various tests against available collocated GNSS/Leveling observations have been performed to find the optimal cut-off degree while the evaluation of the model was carried out over 533 geodetic benchmarks in the entire study area, where accurate static GNSS observations and orthometric heights from the Hellenic Military Geographic Service (HMGS) were available.
Ocean carbon cycle feedbacks and the seasonal cycle of the carbonate system under ocean alkalinization
Authors: Schwinger Jörg , Bourgeois Timothée
Published: February 2023

Ocean Alkalinization deliberately modifies the chemistry of the surface ocean to enhance the uptake of atmospheric CO2. Here, we quantify, using idealized and scenario Earth system model (ESM) simulations, changes in carbon cycle feedbacks and in the seasonal cycle of the surface ocean carbonate system due to ocean alkalinization. We find that both, the sensitivity to changes in atmospheric CO2 concentration (carbon-concentration feedback) as well as the sensitivity to temperature changes (carbon-climate feedback) are enhanced. While the temperature effect, which decreases ocean carbon uptake, remains small in our model, the carbon-concentration feedback enhances the uptake of carbon due to alkalinization by more than 20% compared to the carbon sequestration that alkalinity addition would facilitate at constant CO2 levels. This effect depends on the trajectory of atmospheric CO2 concentration, and leads to an increased loss of carbon from the ocean if net emissions become negative. The seasonal cycle of air-sea CO2 fluxes is enhanced due to an increased buffer capacity in an alkalinized ocean. The seasonal cycle of H+-ion concentration is also enhanced, although it remains smaller than under preindustrial conditions. This, together with an increased seasonal cycle of the aragonite saturation state in some regions, has the potential to adversely affect ecosystem health.
The estimation of Crop Land Productivity based on satellite and biophysical modelled data
Authors: Kryvobok Oleksii
Published: February 2023

To increase the efficiency of agricultural activities related to the crop production, it isimportant to assess the potential yield of territory, especially in the context of climate change. Theestimation of potential yield consists in determining the maximum level of biological or economicproductivity of crop under the constraints of soil fertility, climate, and the consequences ofanthropogenic impact on the agroecosystem.In this study disclosed the methodology of crop potential yield estimation based onProductivity Index of Cropland (PIC) in Ukraine. This index can identify the spatial distributionpattern of a cropland productivity from a field to a district/region or a country level. Majorcomponents of the PIC, are the average NDVI based on remote sensing data and the averagesimulated yield storage for specific crops. The average maximum of NDVI values on pixel level for15 years have been obtained from MODIS and shows biomass of plants, that related to yield with aspatial resolution of 250 by 250 m.  The spatial distribution of NDVI values shows a spatialinhomogeneity of soil types and topography that is mainly related to soil moisture (one of the maindrivers of yield). The simulated yield storage of specific crops shows joint influence of weatherparameters and soil type on yield. In this research, the WOFOST model has been used to simulateyield storage on climatic grids 9 by 9 km for 15years. Then, calculated average values of modeloutput have been interpolated to pixel level of MODIS NDVI data and combined with these values.Final step is cluster analysis which have been used to partition PIC values on pixel level to theclusters with a range of PIC values from 0 to 1. PIC is a good indicator of the potential croplandproductivity and can be builds for the different time periods. The PIC allows to determine thesuitability and productivity of agricultural crops from field level and among different areas fordemarcating and identifying agricultural regions. The farmers, planners and policy makers will beable to make decisions by considering the outcome of the PIC that would lead to better performancein the agricultural sector according to the climate change.
Mapping surface flow pathways in urban areas using UAV-based thermal imaging in combination with flooding experiments
Authors: Bartsch Jan , Schuetz Tobias
Published: February 2023

In recent years, heavy rainfall events and resulting flash floods have increasingly caused widespread damage to public and private technical infrastructures in Germany. Flood events occurred often at smaller water bodies or as hillslope surface runoff far from the actual watercourses. During extreme events technical measures are often overloaded, so that in addition to local property protection planned emergency runoff pathways can be designated as an essential element of water-sensitive urban development.The research project ‘Urban Flood Resilience - Smart Tools’ (FloReST), funded by the German Federal Ministry of Education and Research (BMBF), is exploring those measures to increase the resilience of infrastructures after flash floods.The aim of this study is the development and demonstration of an experimental setup to improve high-resolution digital mapping of existing surface flow pathways in urban areas using UAV-based thermal imaging in combination with flooding experiments. For this purpose, already known critical points, i.e., dysfunctional emergency drainage sections in the urban infrastructure within the City of Trier, Germany were identified.Within this setting, during relatively warmer or colder days, respectively, we use artificial water releases as a thermal marker of the potentially emerging surface flow pathways. Combining UAV-based visual (RGB) and thermal (infrared) imaging, high-resolution mapping of the potential surface flow paths and their Thalweg is then possible.Using a hydrological model allows for determining extreme discharges potentially generated in the connected catchment areas. Based on a digital terrain model the locally surveyed water levels and flow paths are then scaled up to potentially occurring water levels during extreme discharges. Depending on the occurrence probability of the extreme discharges a set of high-resolution GIS-datasets of the emergency surface flow pathways around objects at risk of flooding can be generated.
Increasing the value of windstorm damaged forest: combining restoration practices and agroforestry
Authors: Marangon Davide , Lingua Emanuele , Betetto Claudio , Cadez Luca , Alberti Giorgio
Published: February 2023

After stand-replacing windstorm salvage logging is the most common practice for recovering economic losses in managed forests and for reducing the risk of subsequent disturbances (e.g. bark beetle outbreaks). To restore forest cover timely after these interventions is therefore necessary, in order to limit the reduction of forest ecosystem services (ES) provision. In the first years following the disturbance and subsequent interventions, there is a need to monitor natural regeneration dynamics in damaged areas, in order to implement active restoration activities if necessary. In this study, we analyze the natural regeneration dynamics in 148 areas damaged by storm Vaia (2018) and salvage logged with different techniques in Northeast of Italy. Results show that regeneration species composition is driven mainly by previous stand composition, with some exceptions depending on seed dispersal strategy. Distance from the edge significantly influences the regeneration occurrence in large gaps and affects the browsing damage percentage, together with deadwood presence. Moreover, site factors, disturbance legacies, and logging methods reveal to be key points to consider in the post-disturbance management strategies definition. To reduce economic losses and exploit the windthrown areas in the short-term, it is possible to integrate reforestation with agroforestry practices (e.g. berries and honey production). This is the framework of the LIFE VAIA project, which aims to integrate innovative local agroforestry practices with artificial regeneration to restore forest cover, increasing the value of forest ecosystems and the ecological and socio-economical resilience of damaged forest ecosystems under future climate changes.