bluuebunny/crossref_metadata_2025 huggingface dataset:
CARRA-driven simulation of Greenland Ice Sheet surface mass balance at 2.5 km resolution
Authors: Larsen Mathias , H. Mottram Ruth , L. Langen Peter
Published: February 2023

Projections of present and future ice mass loss of the Greenland Ice Sheet are important for assessing its contribution to future sea-level rise. Critical for the total mass balance is the surface mass balance (SMB) which can be estimated from models, and improving these models can help to further constrain the uncertainties in future projections.In this project, we use the CARRA reanalysis dataset generated from the HARMONIE-AROME weather forecast system to force an SMB model. The CARRA dataset is remarkable for its 2.5 km horizontal resolution providing unprecedented spatial detail. This is particularly important at the ice-sheet margins where both accumulation and ablation processes are impacted by strong topographic gradients. For example, the greater spatial detail is expected to provide more realistic profiles of accumulation and drying of airmasses from the coast toward the interior, in turn improving the SMB simulation.The SMB model utilizes a subsurface scheme that consists of columns with 32 layers in the vertical. Driven by the atmospheric input, the SMB model computes all the interactions between the atmosphere and subsurface layers, such as accumulation, melting, percolation, refreezing and runoff. Using this SMB model, we performed a CARRA-driven simulation over the period 1991-2020 on the 2.5 km CARRA grid.Our initial results show the CARRA-driven SMB model yielding somewhat higher SMB values compared to other published SMB products. The ice sheet-wide totals of accumulation and melt are comparable to other products. However, the location of maximum melt contributions is shifted further towards the interior of the ice sheet in the CARRA-driven simulation. This allows for larger refreezing and contributes significantly to the high SMB seen in the CARRA-driven simulation. Here, we evaluate the SMB model output and driving fluxes against PROMICE data and satellite observations and provide a new updated assessment of Greenland ice sheet SMB.
Land use changes and spatial susceptibility in small Mediterranean basins
Authors: Triano-Cornejo Ana , Pérez-González María Eugenia , Ruiz-Sinoga José Damián
Published: February 2023

Soil erosion is one of the most recurrent environmental problems of public interest today. The western Mediterranean is an area sensitive to the effects of Climate Change, according to the latest IPCC Sixth Assessment Report, due to the proven increase in extreme events such as heat waves, extreme rainfall and droughts. Within this, the importance of competition in the territory between tourism and agriculture will be the result of radical changes in land use that are affecting the ecomorphological system to the point of making it even more susceptible due to the emergence and increase of high risks in the Mediterranean basins. Therefore, it will be essential to determine the levels of susceptibility of the basins under study with respect to erosive processes in order to create new mitigation measures to improve soil management and reduce these risks. Through this study we intend to analyze changes in land use and territorial susceptibility in several basins in southern Spain, in Malaga. The main objective is to determine the incidence and susceptibility of these basins and to analyse how they have been affected by land use changes through an observation of land use changes and the application of the RUSLE model. This project will look at the differences between two contrasting basins. One basin with steep slopes and the emergence of more sensitive crops, such as vineyards, which will increase the fragility of Mediterranean basins after torrential events, causing the appearance of a higher risk of erosion, while the other basin will be differentiated with the appearance of clearings that decrease the steep slopes together with changes to more competitive crops, such as subtropical crops. The results demonstrate the correlation between land use and torrential events in Mediterranean basins with respect to their susceptibility in their ecogeomorphological system.
The Crustal Structure of the Anatolian Plate: Evidence from Modified H-K Stacking of Teleseismic Receiver Functions
Authors: Ogden Chris , Bastow Ian
Published: February 2023

Understanding the crustal structure of the Anatolian Plate has important implications for its formation and evolution, including the extent to which its high elevation is maintained isostatically. However, the numerous teleseismic receiver function studies from which Anatolian Moho depths have been obtained return results that differ by <21km at some seismograph stations. Thus, we determine Moho depth and bulk crustal Vp/Vs ratio (K) at 582 broadband seismograph stations across Anatolia, including ~100 for which H-K results have not been reported previously. We use a modified H-K stacking method in which a final solution is selected from a suite of up to 1000 repeat H-K measurements, each calculated using randomly-selected receiver functions and H-K input parameters, with the result quality assessed by ten quality control criteria. By refining Moho depth constraints, including identifying 182 stations, analysed previously, where H-K stacking yields unreliable results (particularly in Eastern Anatolia and the rapidly-uplifting Taurides), our new crustal model (ANATOLIA-HK21) provides fresh insight into Anatolian crustal structure and topography. Changes in Moho depth within the Anatolian Plate occur on a shorter length-scale than has sometimes previously been assumed. For example, crustal thickness decreases abruptly from >40km in the northern Kirsehir block to <32km beneath the Central Anatolian Volcanic Province and Tuz Golu basin. Moho depth increases from 30-35km on the Arabian Plate to 35-40km across the East Anatolian Fault into Anatolia, in support of structural geological observations that Arabia-Anatolia crustal shortening was accommodated primarily on the Anatolian, not Arabian, Plate. However, there are no consistent changes in Moho depth across the North Anatolian Fault, whose development along the Intra-Pontide and Izmir-Ankara-Erzincan suture zones was more likely the result of contrasts in mantle lithospheric, not crustal, structure. While the crust thins from ~45km below the uplifted Eastern Anatolian Plateau to ~25km below lower-lying western Anatolia, Moho depth is generally correlated poorly with elevation. Residual topography calculations confirm the requirement for a mantle contribution to Anatolian Plateau uplift, with localised asthenospheric upwellings in response to slab break-off and/or lithospheric dripping/delamination example candidate driving mechanisms.
Numerically efficient algorithm for simulating variably saturated flow in heterogeneous layered porous media
Authors: Suk Heejun , Piao Jize , Han Weon Shik , Kim Seong-Kyun
Published: February 2023

A new numerical method was developed to accurately and efficiently compute a solution of the nonlinear Richards equation with a layered soil. In the proposed method, the Kirchhoff integral transformation was applied. However, in the Kirchhoff integral transformation approach, the transformed Kirchhoff head has dyadic characteristics at the material interface between different soil types. To avoid the dyadic characteristics at the material interface, a truncated Taylor series expansion was applied to the Kirchhoff head at the material interface and so the Kirchhoff head was replaced with a single pressure head value at the material interface. Accordingly, through the Taylor series expansion, a set of algebraic equations in the one-dimensional control volume finite difference discretized system formed a tridiagonal matrix system. Through a series of numerical experiments, the new method was compared to other numerical methods to determine its superiority. The results clearly demonstrated that the approach was not only more computationally efficient, but also more accurate and robust than other numerical methods. Computational performance was greatly enhanced with the proposed method, and which could be used to simulate complicated heterogeneous flow at a large-scale watershed or regional scale.AcknowledgmentsThis work was supported by the basic research project (23-3411) of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Science and ICT.
An integrated hydrodynamic model for flash flood and debris flow simulations
Authors: Xia Xilin , Jarsve Kristine , Dijkstra Tom , Liang Qiuhua , Meng Xingmin
Published: February 2023

Climate change is forecasted to result in more frequent and intense storms, which in turn are likely to cause more flash floods and other hazardous processes in steep hilly and mountainous catchments. These flash floods are driven by complex and rapid overland flow responses to intense rainfall across these catchments. Where loose slope or valley-based deposits are available, flood water may mobilise these materials and transform into dynamic high-velocity, high-density debris flows that can pose significant threats to people, property, and infrastructure considerable distances away from the areas where these deposits are mobilised, exacerbating the already devastating situation caused by flooding. Hydro-dynamic models solving the full shallow water equations (SWEs) have shown great potential to reliably simulate the dynamics of overland flows and flash floods at catchment scales. However, simulating the transition from flash flood into debris flow is still technically challenging because of the difficulty of simulating erosion and deposition processes robustly. A reason is that the commonly used method for calculating erosion and deposition rate may suffer from singularity in the presence of vanishing velocity, which poses a major challenge for practical applications. In this work, we have developed a novel integrated hydrodynamic model for simulating flash floods and debris flows. Overland flows, change of debris concentration and bed elevation change are simulated simultaneously to model the transition between flash flood and debris flow. The overland flow processes are simulated by solving the full SWEs using a Godunov-type finite volume method. A novel method for calculating erosion and deposition rates is incorporated into the SWEs-based model to simulate the change of debris concentration and bed elevation change. The new method can maintain numerical stability and accuracy even in the presence of vanishing velocity. Therefore, the new model can effectively simulate the full process of rainfall-runoff-flooding turning into debris flows. Satisfactory simulation results have been obtained for both laboratory-scale and real-world test cases. The new model has the potential to be applied for flash flood/debris flow risk assessment and early warning.
Airborne measurements of the cloud impact on the surface radiative energy budget in the Fram Strait
Authors: Becker Sebastian , Ehrlich André , Schäfer Michael , Wendisch Manfred
Published: February 2023

Clouds play an important role in the climate system of the Arctic. The interaction of clouds with atmospheric radiation has a significant influence on the radiative energy budget (REB) of the Arctic surface, which is quantified by the surface cloud radiative effect (CRE). Due to the counteraction of the cooling effect of clouds in the solar and their warming effect in the thermal-infrared spectral range, the total CRE depends on a complex interplay of the illumination, surface, thermodynamic, and cloud conditions.To characterize the CRE for a variety of environmental conditions, broadband radiation measurements were performed during three seasonally distinct airborne campaigns. The flights were conducted over sea ice and open ocean surfaces in the eastern Fram Strait. The analysis focusses on the differences of the CRE with respect to the different campaigns and surface types. It was found that clouds cool the open ocean surface during all campaigns. In contrast, clouds mostly have a warming effect on sea ice–covered surfaces, which neutralizes during mid-summer. Given the seasonal cycle of the sea ice distribution, these results imply a cooling effect of clouds on the surface during the sea ice minimum in late summer and a warming effect during the sea ice maximum in spring in the Fram Strait region. The variability of, e. g., cloud and synoptic conditions causes deviations of the CRE from these statistics. In particular, the study presents the evolution of the CRE during selected cases of warm air intrusions and marine cold air outbreaks.
Effect of sample size, sampling design and calibration model on generating soil maps from proximal sensing data for precision liming
Authors: Vogel Sebastian , Schmidinger Jonas , Schröter Ingmar , Bönecke Eric , Rühlmann Jörg , Kramer Eckart , Mulder Titia , Heuvelink Gerard , Gebbers Robin
Published: February 2023

For site-specific estimation of lime requirement, high-resolution soil maps of clay, soil organic carbon (SOC) and pH are required. These can be generated using digital soil mapping (DSM), in which prediction models are fitted on covariates from proximal soil sensors. However, the quality of the maps derived may differ significantly depending on the methodology applied. Hence, we assessed effects of (i) calibration sample size (5-100), (ii) sampling design (simple random sampling (SRS), conditioned Latin Hypercube sampling (cLHS) and k-means sampling (KM)) and (iii) prediction model (linear regression (LR) and Random Forest (RF)) on the prediction performance for the above mentioned three soil properties using data from two multi-sensor platforms. The present case study is based on a geostatistical simulation using 250 soil samples from a 51 ha field in Germany. Among others, Lin’s concordance correlation coefficient (CCC) and root-mean-square error (RMSE) were used to evaluate model performances. Results show that with increasing sample size, improvements of RMSE and CCC decreased exponentially. We found best median RMSE values at 100 calibration soil samples, i.e. 1.73%, 0.3 and 0.21% for Clay, pH and SOC, respectively. However, already with 10 samples, models of moderate quality (CCC > 0.65) can be obtained for all three soil properties. Both, cLHS and KM obtained significantly better results than SRS. At smaller sample sizes, LR showed lower median RMSE values than RF for SOC and pH. Nonetheless, with at least 75-100 and 25-30 samples, RF eventually outperformed LR. For clay, median RMSE was lower with RF, regardless of sample size.
b- value mapping in Sikkim and adjoining Himalayas
Authors: Maitreyi  , Singh Chandrani , Singh Arun , Uthaman Mita , Dutta Abhisek , Kumar Gaurav , Kumar Dubey Arun
Published: February 2023

The b-value in the frequency-magnitude relation is one of the fundamental seismological parameters to define an assemblage of earthquakes. This study focuses on the use of b-value as a precursor to know the chances of occurrence of major earthquake events in Sikkim and adjoining Himalayas. A catalogue containing 9192 earthquakes (M ≥ 0.30) recorded across Nepal, Sikkim and Bhutan Himalayas during 1980-2022 is considered for the present study. The study area has been divided into three blocks encompassing Nepal, Sikkim and Bhutan segments and the b-values are computed. The results show variations in b-value across these three blocks which might be associated with the differential stress pattern across the regions. Further, we map the spatial variation of frequency-magnitude distribution by dividing the entire region into 0.1⁰ x 0.1⁰ grids. The grids with less than 30 earthquake events are excluded to ensure the reliability of our results. The results suggest that the entire segment belongs to a high stressed region. The lowest b-values are mostly observed in Sikkim and western Nepal, reflecting the possible zones of future earthquakes.
Reduction in Winter Surface Heat Loss over the Past 70 Years Threatens North-West Mediterranean Convection
Authors: Josey Simon , Schroeder Katrin
Published: February 2023

Over the past 70 years, a major change in winter air-sea heat loss between the North-west Mediterranean (NWMed) and the Aegean Sea,  is revealed using the ERA5 amd 20CRv3 atmospheric reanalyses. The NWMed heat loss weakens from -154 Wm-2 in 1951-1985 to -137 Wm-2 in 1986-2020 as a results of weaker latent heat loss. This long-term weakening threatens continued dense water formation, and we show by evaluation of historical observations that winter-time ocean convection in the NWMed has declined by 40% from 1969 to 2018. Extension of the heat flux analysis reveals changes at other key dense water formation sites that favour an eastward shift in the locus of Mediterranean convection towards the Aegean Sea (where heat loss has remained unchanged at -172 Wm-2). The contrasting behaviour is due to differing time evolution of sea-air humidity and temperature gradients. These gradients have weakened in the NWMed due to more rapid warming of the air than the sea surface but remain near-constant in the Aegean. The different time evolution reflects the combined effects of global heating and atmospheric circulation changes which tend to offset heating in the Aegean but not the NWMed. The shift in heat loss has potentially significant consequences for dense water formation at these two sites and outflow to the Atlantic. The process of differential heat loss change in the Mediterranean Sea has implications for temporal variations in the balance of convection elsewhere e.g., the  high latitude Atlantic/Arctic margin dense water formation sites (Labrador-Irminger-Nordic Seas).
Airborne and marine microplastics in the Southern Ocean environment
Authors: Aves Alex , Livingstone Emelia , Law Cliff , Revell Laura , Gaw Sally
Published: February 2023

In recent years, microplastic transport through the atmosphere has gained interest. This pathway allows microplastics to reach remote regions of the world and draws attention to the impact which they may have on global climate processes and human health. Remote regions, particularly in the Southern Hemisphere, are currently under-researched and the understanding of airborne microplastics still in its infancy. Atmospheric deposition and seawater samples were collected on board a RV Tangaroa voyage, which sailed from Wellington, New Zealand to the Ross Sea, Antarctica in January 2021. Marine and atmospheric microplastics were collected and analysed spectroscopically to confirm polymer composition. The findings from this study will be discussed, highlighting the ubiquitous nature of microplastics throughout the Southern Ocean. This study contributes a unique data set from a remote region of the world, and further develops our understanding of marine-atmosphere fluxes of microplastics.
A Radiocarbon Inventory of Switzerland’s Lakes
Authors: White Margot , Mittelbach Benedict , Rhyner Timo , Haghipour Negar , Blattmann Thomas , Wessels Martin , Dubois Nathalie , Eglinton Timothy
Published: February 2023

The Radiocarbon Inventories of Switzerland (RICH) project aims to construct the first national-scale census of (radio)carbon across aquatic, terrestrial, and atmospheric reservoirs. Within the carbon cycle, inland waters play a crucial role with lakes integrating carbon from various sources within their catchments in addition to that fixed by local primary productivity. Here we will present radiocarbon measurements of water-column dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC) from 15 lakes across Switzerland covering a range of sizes, elevations, and trophic states. In addition, a year of monthly water column measurements from Switzerland’s two largest lakes - Lake Constance and Lake Geneva - reveal seasonal trends resulting from changes in productivity and river inflow. Preliminary results show that the average radiocarbon signature of DIC in both Lake Constance and Lake Geneva is depleted in 14C relative to atmospheric CO2, indicating a ca. 15-20% contribution from bedrock weathering (14C-dead carbon). The timeseries at Lake Constance builds on earlier measurements which have shown a decline in DI14C since the late 1960s due to decreasing concentrations of bomb radiocarbon in the atmosphere. DO14C values in Lake Constance are more enriched compared to DI14C, indicating the importance of terrestrial DOC sources. In contrast, DO14C values in Lake Geneva are similar to DI14C, consistent with lake primary productivity as the main source of DOC. Overall, variations in radiocarbon values between different lakes are much greater than seasonal variations observed in either Lake Constance or Lake Geneva. These results form the basis of a radiocarbon inventory of Swiss lakes and provide new insights into carbon cycling in these dynamic aquatic systems.
Constraining the crustal and mantle conductivity structures beneath islands by a joint inversion of multi-source magnetic transfer functions
Authors: Chen Chaojian , Kuvshinov Alexey , Kruglyakov Mikhail , Munch Federico , Rigaud Rafael
Published: February 2023

In this study, we present a quasi-1D tool to simultaneously invert multi-source magnetic transfer functions (TFs), including tippers, solar global-to-local transfer functions (TFs) originating from the signals due to ionospheric source, and global Q-responses originating from the signals due to magnetospheric source. We jointly invert the aforementioned TFs to constrain the local 1-D conductivity structures beneath three islands in the Atlantic (Tristan da Cunha), Indian (Cocos), and Pacific (Oahu) Oceans. The recovered conductivity profiles appeared to be consistent with the presence of upper mantle plumes beneath the Tristan da Cunha and Oahu Islands. Our results indicate resistive lithosphere of different thicknesses beneath considered three islands, in agreement with the age of the ocean floor. Besides, new conductivity profiles suggest warmer-than-average mantle temperatures and the presence of a small fraction of melt beneath Tristan da Cunha Island. At the same time, the conductivities beneath Cocos Island are in good agreement with estimates expected for ambient mantle conditions.
A laboratory experiment on the effect of waves on the transport and dispersion of macro, meso, and microplastics in the surf zone
Authors: Núñez Paula , Romano Alessandro , García-Alba Javier , Sánchez Margot , Mendoza Andrés P. , Abascal Ana J. , García Andrés , Vidal Cesar , Besio Giovanni , Medina Raúl
Published: February 2023

Plastic debris is currently a significant threat to marine and coastal ecosystems. Most previous research focused on the behavior of drifting macro and mesoplastics on global and regional ocean scales. Furthermore, a few more recent studies provide some first insights into the microplastic dispersion in coastal areas. These studies found that waves and wind, as well as the density, size, and shape of microplastics, drive their transport and dispersion in coastal areas; however, they point to the need for a more extensive characterization. This laboratory study assesses the effect of waves and wave-induced currents on the input rate from land to sea and on the cross-shore transport and dispersion of different types of plastic debris, including the macro and mesosizes, in addition to microplastics. A total of 15 types of plastic debris characterized by different sizes, shapes, and densities, including face masks, were analyzed under regular and irregular wave conditions. The results show that the input rates and transport of plastic debris in the marine environment depend on the position they acquire in the water column, which is related to the terminal velocities and the wave steepness. A higher input rate from the beach was found for plastic materials moving closer to the sea bottom and under less steep wave conditions, as these conditions allow items to escape from coastal entrapment. Furthermore, greater onshore transport was observed for plastic debris that showed greater buoyancy under steeper wave conditions. Regarding the cross-shore distribution, the heaviest plastic debris that managed to be transported accumulated in the breaking zone, while the buoyant elements showed a predominant accumulation closer to the shoreline.
Parallel Electric Field and Double Layers at Non-Maxwellian Effective Temperature Scales in Near Earth Space Plasmas
Authors: Khalid Saba , Qureshi Muhammad Nouman Sarwar
Published: February 2023

Magnetic reconnection interlinks different regions of plasmas by converting magnetic energy into plasma heating and energization of particles. It causes abrupt changes in the temperature, density, field strength and flow speed. The physical mechanism behind charge particle energization during magnetic reconnection is best explained by the concept of double layers (DLs) and associated parallel electric fields. In-situ observations of reconnection sites by Magnetospheric Multi Scale (MMS), THEMIS and FAST have confirmed that charge particle energization in these regions is associated with large parallel electric fields in auroral regions, Earth’s plasma sheet and separatrix region of Earth’s magnetosphere. The reported literature motivated us to investigate double layers and associated electric field at the reported sites by using multi-fluid theory for electron-ion plasma and employing fully nonlinear Sagdeev potential approach. We have considered the ion inertial effect whereas electrons are assumed to be non-Maxwellian following (r, q) distribution function. In particular, parallel electric fields associated with Alfvenic double layer have been investigated at non-Maxwellian effective temperature scales and then compared with the observations. We have seen that the characteristics of DLs associated with the kinetic Alfvén waves are significantly modified due to the nonthermal parameters r and q, propagation angle 𝜃, and Alfvénic Mach number 𝑀A. Our current study supports both the compressive and rarefactive double layer structures.
Abiotic transformation of iodine species in ice and its environmental implications
Authors: Kim Kitae
Published: February 2023

Ice is one of the most common matters on earth and regarded as active reaction media in the environment. Recently, it was reported that several chemical reactions in frozen state proceed unexpected pathway and markedly accelerated compared to those in aqueous phase. The freeze concentration of reactants, protons, and gases in ice grain boundaries between ice crystals is regarded as main driving force for the intrinsic chemical processes in ice. Iodine plays important roles on ozone depletion event, oxidation of gaseous elemental mercury (Hg0) to Hg(II), oxidizing capacity in atmosphere, control of HOx and NOx ratio in marine boundary layer, and the formation of ultrafine aerosol particles as cloud condensation nuclei(CCN). Furthermore, iodine is also proposed to be a potential proxy for past sea ice variability. However, the chemical behavior of iodine compounds during transport and after deposition is not well understood. Although the intensive investigations on chemical behavior of iodine species such as theoretical studies, laboratory experiments, and field observations, the clear pathway and mechanism of iodine formation in polar regions are still uncovered. In this presentation, I want to introduce several unique chemical processes in ice related to iodine compounds such as 1) redox reactions of iodide (I-), iodate (IO3-), periodate (IO4-) in ice, 2) interaction between iodine and metal oxides, 3) degradation and removal of pollutants with iodine species for the better understanding of fate of iodine species in polar environment. The detailed experimental conditions and mechanism will be discussed in the presentation
Predicting landslide failure mechanisms using advanced mathematical models
Authors: Bhuyan Kushanav , Rana Kamal , Ferrer Joaquin , Nava Lorenzo
Published: February 2023

Understanding the process of landslide failure is crucial for predicting and minimizing the consequences of landslides. Landslide failure can be caused by a variety of factors, including geology, topography, and soil conditions, while environmental triggers such as precipitation and earthquakes initiate the movement. We can better understand the risks associated with landslides and apply appropriate steps to decrease those risks by disclosing the precise mechanisms that contribute to landslides in a specific location. To reveal these mechanisms, we use an advanced mathematical model called the Topological Data Analyses (TDA) that decodes the landslide's shapes and configurations as it includes factors such as the slope of the failures, the presence of cliffs or other steep terrain features, and kinematic propagation of the failures. Then we use these features to categorize the different landslide failure mechanisms such as slides, flows, falls, and complex landslides. Our study paves the way to classify existing and past inventories that miss these failure type information. This information will help the landslide predictive community in general and in the different stages of the landslide risk cycle as pertinent information of failure mechanisms are important for effective forecasting, susceptibility, hazard, and risk modelling.
Impacts of the 2018–2019 Central European drought in North-Eastern Germany
Authors: Conradt Tobias
Published: February 2023

The 2018–2019 drought was probably the most severe in Central Europe since the first half of the 16th century. What effects were caused in North-Eastern Germany including the capital city region and the driest part of the country where sandy soils predominate? This is illustrated using both observations from the environment and data from statistical offices.A couple of indicators – SPEI (meteorological drought), SMI (soil moisture), GGI (groundwater), SSI (streamflow), and PPI (plant physiology) – show the drought propagation from meteorology into the eco-hydrological system. Soil moisture and plant physiology showed decreasing tendencies already before 2018 when the study region was challenged by massive crop yield losses (−40% for maize compared to the 2012–2017 yield average). Forest trees suffered with delay – drought-triggered bark beetle attacks caused emergency logging and forest diebacks especially in spruce trees still in 2021.Agriculture and forestry represent only about 1% of the regional economy (measured by gross value added), and drought effects were hardly noticeable in industry and service sectors, though. This is in remarkable contrast to the economic shocks caused by the 2008–2009 global financial crisis and the recent pandemic which left their marks in the economic time series. The question remains whether the apparent stability of the regional socio-economic system against extreme drought can still be maintained in the next decades with higher probabilities for extreme events.
Mapping and characterising tree mortality in California at individual tree level using deep learning
Authors: Cheng Yan , Oehmcke Stefan , Brandt Martin , Das Adrian , Rosenthal Lisa , Saatchi Sassan , Wagner Fabien , Verbruggen Wim , Vrieling Anton , Beier Claus , Horion Stephanie
Published: February 2023

Tree mortality caused by natural disturbances, such as droughts, insects, and wildfires, is a global issue due to increased frequency and severity of extreme weather. California has been a major hotspot of large-scale tree mortality since 2012-2015 drought. Despite many local studies, there is no confident count of dead trees at the state level. Here we mapped all individual dead trees in California using submeter aerial images and Conventional Neural Network (i.e. EfficientUnet architecture). The model accuracy is about 96% and 83% when comparing to visually interpreted samples from aerial photos and in-situ observations, respectively. In total, we found more than 80 million dead trees from NAIP imagery in 2020, which accounts for 2% of trees reported in 2011. About half of the dead trees belongs to California mixed conifer group. North coast and central and southern Serrie Nevada are the most affected regions. Based on the localization and segmentation of every single dead tree, we retrieved mortality traits (i.e. dead tree density, dead crown size, and classification of old or recent death) and identified hotspots that have emerging mortality and high wildfire fuel load. The mortality traits, along with individual dead tree location at the state scale, provides unprecedented detailed information for forest management and improved carbon accounting, helping to understand dynamics and causes of tree mortality in a changing climate.
Assessment of direct and indirect emissions from the wastewater treatment plant and sludge processing: A case study
Authors: Vidyarthi Praveen Kumar , Arora Pratham , Blond Nadège , Ponche Jean-Luc
Published: February 2023

Due to rapid urbanisation and population, a constant supply of clean and fresh water has come under stress. Raw water must be continuously treated and supplied to satisfy the day-to-day needs for potable water for household use. To find a solution to the issue, several governments worldwide have moved their focus to water and sanitation. Large sewage and effluent treatment facilities are continuously working to treat wastewater, which is the most crucial step in addressing the problem of fresh water. Sludge is the main by-product produced by these treatment plants, which creates a challenge when it comes to disposal. The sludge is processed in the treatment facilities before being disposed of, allowing for better waste management. In the treatment process of the wastewater, from the moment the wastewater enters the treatment facility until the sludge is disposed of, there are multiple points at which emissions are produced. These emissions need to be evaluated and dealt with, as they have the potential to significantly impact climate change and the depletion of the ozone layer. The authors have analysed the emissions using several methodologies, including IPCC inventories, life cycle assessment, and many more. The study's findings indicate that a significant quantity of greenhouse gas emissions (directly and indirectly) and air pollutants are emitted during the process of treating wastewater and disposal of sludge.
Pumping strategies towards sustainable use in a stressed aquifer: A case study at the Eastern Mancha Aquifer (Spain)
Authors: A. Godoy Vanessa , Gómez-Hernández Jaime
Published: February 2023

The aquifers that support irrigated agriculture are being depleted in many parts of the world. In Spain, the situation is not different, and 27% of its aquifers are in bad quantitative condition, mainly due to overexploitation related to agricultural activities. Although the most obvious solution to that problem is to reduce pumping, the quantitative impact of reduced pumping towards sustainable use of groundwater is anything but obvious. We have analyzed the response of the Eastern Mancha aquifer in Spain to pumping reduction scenarios to find ways to stabilize and, ideally, increase aquifer levels. We apply a water balance approach conceived by geologists at the Kansas Geological Survey, in which storage variation is obtained by subtracting pumping from net input, and a linear relationship is established between annual pumping and average water decline. This relationship can then be used to assess the reliability of the data, the sustainability of pumping, the targets of the ongoing management strategies, and the pumping reductions required to stabilize water levels. This method is applied to data coming from 36 wells measured annually from 2011 to 2020. Precipitation data from three stations are used to assess the consistency of groundwater abstraction data. Although we know that conceptually the relationship between the average water level change and the total pumping may not be necessarily linear, the results are coherent with the historical water use behavior for the area and show that the method is appropriate to evaluate the data. Negative values of water level change indicate that the aquifer was not in sustainable conditions most of the time. The results also show that groundwater pumping would need to be significantly reduced to achieve higher water levels. This work shows that measured data on water level changes and water use can provide rapid and valuable information on the condition of the Eastern Mancha aquifer, as well as its response to pumping reduction scenarios.This work was developed under the scope of the InTheMED project. InTheMED is part of the PRIMA programme supported by the European Union’s HORIZON 2020 research and innovation programme under grant agreement No 1923.
Assessing future climate risks in a forward-looking approach.
Authors: Meynadier Remi , Rakotoarimanga Hugo , Frobert Bastien , Weisman Anna , Lobligeois Florent , Deroche Madeleine-Sophie
Published: February 2023

Climate change is increasingly recognized as a top global threat impacting human, environmental, and economic systems.When it comes to property & casualty insurance risk, AXA considers every aspect of the risk equation.  As far as natural catastrophes risks are concerned, climate risk is a function of (i) the physical hazard (the severity and frequency of events); (ii) the exposure (the monetary value of insured asset(s)) and (iii) the vulnerability (the susceptibility or damageability of the insured asset(s) to a given hazard intensity). Each of these elements plays a unique role in driving climate risk both now and into the future. The changes AXA see in its year-on-year losses from climate-linked hazards are a function of all risks components and not just the hazard, which is a common misconception.AXA is developing internally Natural Hazard models (or Natural Catastrophe models) to estimate the climate risk damages and losses to individual risks or (re)insured portfolios.To perform forward looking analysis, AXA identified different complementary approaches that could be envisaged to assess the future of natural hazards risks according to both the peril and region combinations AXA has exposure to as the availability and quality of data for the three drivers of the risk. Those approaches have been notably used for several regulatory climate stress tests AXA was involved in.One of them is a global proportional approach simple to implement to consider at a large scale the evolution of hazard, exposure, vulnerability impacts on climate risk for long term time horizons and several warming scenarios. The model is built on current science knowledge related to climate change.A more sophisticated approach for local-scale assessment is currently being developed. It consists in integrating in the Natural Hazard models a modified view of hazard (stochastic events catalogue) / exposure / vulnerability capturing forward-looking scenarios. AXA is currently upgrading all its Natural Hazard models in that direction. AXA Europe Flood risk model is for instance assessing future of fluvial and pluvial risks from modified precipitation datasets representative of future warming scenarios. Future precipitation are made of baseline current precipitation from which a “delta” precipitation is added, based on CMIP6 temperature anomalies and Clausius-Clapeyron scaling. Hydrological and hydraulic models are then run using this new future precipitation datasets to generate stochastic flood events catalogue for future warming scenarios risks assessment.  
Influence of climatic variables on forests condition in Poland in the period 2002-202
Authors: Kulesza Kinga , Hościło Agata
Published: February 2023

Forest ecosystem stress caused by climate change, in particularly prolonged and severe droughts, has already been manifested in several parts of Europe, including temperate and boreal forests. It is likely that droughts and heatwaves will occur more often, which might result in the ecological transition of the forests and loss of biodiversity. The assessment of climate change impact on forest ecosystems is complex, as response can vary in space (depending on the physiological vulnerability of ecosystems and site conditions), time, and among species (species resilience).In this project we investigate the influence of several climatic variables (2 m temperature, rainfall, evapotranspiration and climatic water balance) on the forests condition in Poland in the period 2002-2021. To this end we use ERA-5 Land reanalysis data and vegetation indices – NDVI and EVI – derived from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS) – MOD13Q and MYD13Q. The remotely sensed indicators on vegetation consist of 8-day composites and have 250-m spatial resolution, while the climatic data is 0.1° x 0.1° spatial and 1-day temporal resolution.The spatio-temporal trends of NDVI and EVI were computed for forest areas only, and their statistical significance was assessed. The monthly analyses were carried out for growing season (April-October). Multi-annual trends of climatic variables were prepared not only for the period 2002-2021, but also for the longer period 1971-2021, in order to strengthen the information coming from the climate trend analysis. The influence of the variability of climate elements on vegetation indices was assessed with the methods of linear regressions and spatial correlations. The results were broken down into sub-regions of similar physical-geographical features (nature-forest classification).Identification of the relation between changing climate and forests condition seems crucial, because forests are the important element in the planetary energy balance and CO2 absorption. In Poland almost 30% of country area (9.2 million ha) is covered with forests, but such research have not been conducted so far.
Sustainable groundwater management using a combined simulation–optimization approach
Authors: Anyfanti Ioanna V. , Lyronis Antonis , Diakoparaskevas Paraskevas , Varouchakis Emmanouil , Karatzas George P.
Published: February 2023

The Mediterranean region has been facing human and climate–change threats in the last decades. The current work, within the InTheMED PRIMA project, implements a groundwater simulation model in combination with optimization techniques and aims to elaborate informed alternatives in the decision–making process for the Tympaki study area.  Tympaki is located in the south of Crete and represents one of the most productive areas in the agricultural sector of the island. The economic activities combined with its location make it a very demanding region in terms of water needs. Most of this demand is met from the coastal aquifer and, more recently, from a reservoir. Climate change, the increase in temperatures and decrease in precipitation, cannot guarantee water resources of sufficient quantity and/or quality. To address these issues, an optimization analysis was conducted. The optimization problem was to maximize the pumping rates subject to a water table that improves or maintains the situation in the aquifer. In the case of Tympaki, this also helps solve the problem of saltwater intrusion. FEFLOW was used to simulate groundwater flow in the porous media and MATLAB application was used for optimization. Since groundwater flow is not a linear process, iterative simulation–optimization runs were performed in the framework of piecewise linear optimization. To avoid time–consuming procedures, customized GUIs were developed for better data processing in MATLAB. The simulation–optimization model was applied to recorded measurements and different time periods, as well as to regional climate model data. In addition, different water management scenarios were evaluated including alternative water sources, such as water from the reservoir or treated wastewater. The results are presented in online maps so that they can be disseminated among stakeholders and help inform all interested parties and enable more transparent decision–making.This work was developed under the scope of the InTheMED and Sustain-COAST projects.InTheMED is part of the PRIMA programme supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 1923. Sustain-COAST is funded by the General Secretariat for Research and Innovation of the Ministry of Development and Investments under the PRIMA Programme. PRIMA is an Art.185 initiative supported and co-funded under Horizon 2020, the European Union’s Programme for Research and Innovation.
GlaMBIE – An intercomparison exercise of regional and global glacier mass changes
Authors: Jakob Livia , Zemp Michael , Gourmelen Noel , Dussaillant Ines , Nussbaumer Samuel Urs , Hock Regine , Berthier Etienne , Wouters Bert , Gardner Alex S. , Moholdt Geir , Brun Fanny , Braun Matthias H.
Published: February 2023

Retreating and thinning glaciers are icons of climate change and impact the local hazard situation, regional runoff as well as global sea level. For past reports of the Intergovernmental Panel on Climate Change (IPCC), regional glacier change assessments were challenged by the small number and heterogeneous spatio-temporal distribution of in situ measurement series and uncertain representativeness for the respective mountain range as well as by spatial and temporal limitations and technical challenges of geodetic methods. Towards IPCC SROCC and AR6, there have been considerable improvements with respect to available geodetic datasets. Geodetic volume change assessments for entire mountain ranges have become possible thanks to recently available and comparably accurate digital elevation models (e.g., from ASTER or TanDEM-X). At the same time, new spaceborne altimetry (CryoSat-2, IceSat-2) and gravimetry (GRACE-FO) missions are in orbit and about to release data products to the science community. This opens new opportunities for regional evaluations of results from different methods as well as for truly global assessments of glacier mass changes and related contributions to sea-level rise. At the same time, the glacier research and monitoring community is facing new challenges related to the spread of different results as well as new questions with regard to best practises for data processing chains and for related uncertainty assessments.In this presentation, we introduce the Glacier Mass Balance Intercomparison Exercise (GlaMBIE) project of the European Space Agency, which is building on existing activities and the network of the International Association of Cryospheric Sciences (IACS) working group on Regional Assessments of Glacier Mass Change (RAGMAC) to tackle these challenges in a community effort. We will present our approach to develop a common framework for regional-scale glacier mass-change estimates towards a new data-driven consensus estimate of regional and global mass changes from glaciological, DEM-differencing, altimetric, and gravimetric methods.