bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of factors controlling the runoff coefficient in the Mediterranean context: a case study in central Italy
Authors: Rahi Arash , Rahmati Mehdi , Dari Jacopo , saltalippi Carla , Morbidelli Renato
Published: February 2023

Global warming is affecting hydroclimatic parameters determining changes in temperature and precipitation patterns. In addition, human-induced activities act on the land use and land cover (LULC) features of catchments. Runoff generation can be affected by these factors in both natural and anthropogenic basins. The aim of the current study is to investigate the relationship between the runoff coefficient (Rc), computed by exploiting long-term rainfall and streamflow records, and several features that can potentially affect it, namely meteorological parameters, soil water storage (SWS), and LULC changes through the wavelet coherence analysis. The method has been applied over the Upper Tiber basin at Ponte Nuovo outlet, in central Italy. To facilitate the understanding of the current catchment conditions in terms of surface water availability, a trend analysis has been performed using the Mann-Kendall (MK) test. For the long-term period of 1927-2020, the results reveal a decreasing trend of Rc. In addition, the MK test for seasonal temperature and SWS shows increasing and decreasing trends, respectively. Based on the wavelet analysis, a significant positive correlation is observed between Rc and SWS in the annual cycle with a phase shift of less than one month, while a strong negative correlation is observed between Rc and temperature in the annual period with a phase shift of 3-6 months. The study of the relationship between Rc and LULC changes shows a weak correlation. The lower phase shift between Rc and SWS indicate that Rc is susceptible to SWS in a faster way than other components. These results allows a better understanding of the main factors influencing the Rc over the pilot area; moreover, an extension to other Mediterranean basins is foreseen as a follow-up of this work.
Statistical study of the solar wind properties using the magnetic connectivity from in-situ measurements of Solar Orbiter extrapolated sunward the Solar Corona.
Authors: Dakeyo Jean-Baptiste , Rouillard Alexis , Maksimovic Milan , Réville Victor , Louarn Philippe , Démoulin Pascal
Published: February 2023

Using the magnetic field properties in the interplanetary medium and near the Sun allows to trace back the trajectory of an in-situ observed parcel of solar wind. This kind of study has already shown around 1 AU an anti-correlation between the speed of the wind, and both the expansion factor of the flux tube and the magnetic field magnitude of the source (Wang & Sheeley 1990). In this study we apply the magnetic connectivity to the Solar Orbiter measurements from 0.3 AU to 1 AU, to trace back their source at the solar surface using ADAPT magnetograms. The nominal mission phase data are used (from the beginning of 2021). To better approximate the departure time of the plasma at the Sun and the location of its source, we constrain the trajectory of the solar wind using iso-poly modeling (Dakeyo et al. 2022) from the probe location until the source surface Rss. In addition, we aim to follow the classification of Maksimovic et al. 2020 and Dakeyo et al. 2022, to extrapolate sunward the magnetic condition of the different wind speed populations observed by Solar Orbiter.  This statistical analysis shows that the correlation already observed at 1 AU mentioned above (bulk speed, flux tube expansion and magnitude of the magnetic field) are globally conserved getting closer the Sun between 0.3 AU and 1 AU. Depending the speed of the wind we are also able to estimate typical values of expansion factor, magnitude of the coronal magnetic field, the state of charge for each wind speed populations.
Instruments performance and data quality after 10 years of Swarm in orbit
Authors: Qamili Enkelejda , Forte Roberta , Comparetti Nicola , Tøffner-Clausen Lars , Buchert Stephan , Burchill Johnathan , Siemes Christian , Mizerska Anna , Bregnhøj Nielsen Jonas , Nilsson Thomas , Mazzocato Maria Eugenia , Brazal Aragón María José , Trenchi Lorenzo , Bouffard Jerome , Stromme Anja , Vogel Pierre , Hoyos Ortega Berta
Published: February 2023

Launched by the European Space Agency (ESA) in November 2013, the three-satellite Swarm constellation continues to provide very high-quality measurements of the Earth's magnetic field and associated plasma environment. After around 10 years in space the Swarm mission has achieved remarkable scientific results, opening the door for many innovating applications largely beyond its original scope. With this paper, the authors would like to provide a broad overview of the Swarm mission status and Swarm instruments performance. Moreover, the many improvements obtained from the new Swarm data processing baseline together with other innovative Swarm-based data products and services will be presented.
Estimation of crop fractional cover (FCover) in smallholder farming systems using UAV and Sentinel-2 images : Case study of a Senegalese agroforestry parkland
Authors: Diack Ibrahima , Leroux Louise , Heuclin Benjamin , Letourmy Philippe , Diene Serigne Mansour , Audebert Alain , Roupsard Olivier , Diouf Abdoul Aziz , Sarr Idrissa , Diallo Moussa
Published: February 2023

Scattered trees in farmer fields, also known as agroforestry parkland, are integrated part of West African smallholder agricultural landscapes. While they are used for centuries by farmers, they are now recognised by the scientific and politic communities as a mean to face climate changes (Skole et al., 2021). Fractional cover (FCover) is an important biophysical parameter allowing to monitor the crop growth. Satellite images has been proven very efficient for crop FCover estimation in various ecosystems (Gräzing et al 2021). However, in agroforestry parklands, the presence of trees inside the fields induced a huge variability that can be hardly captured by traditional approach relying on satellite images and ground information. We propose an original empirical framework relying on the combining use of UAV-based FCover and Sentinel-2 data to estimate the pearl millet FCover at landscape scale in an agroforestry parkland of Senegal. 6 UAV images were acquired during the 2021 cropping season and the millet FCover has been derived from a threshold of UAV images for 95 subplots on a 3-m grid and used as targeted variable. 4 vegetation indices and 8 texture featured calculated from S2 data were used as models’ predictors. 3 machine learning regression algorithms (RF, GBM and SVM) and a multiple linear regression (MLR) model were calibrated over the 3-m grid using a cross-validation approach and different scenarii of modelling were tested: (1) fit the four models date by date dataset, (2) fit the four models on all dates dataset with and without date information as predictor, (3) single models vs a meta-model resulting from the stacking of the different models. Our results evidenced that for each model tested the accuracy is dependent to the millet growth stage, the vegetative period being overall the one allowing to reach the higher accuracy. MLR is not adapted to estimate millet FCover (R² between 0.07 and 0.13) while the machine learning models gave overall good results, RF being the better one (R² between 0.45 and 0.69).We have shown that the use of date information as predictor allowed to improve the FCover estimation (R² increases up to 24%) however, the use of a meta-model didn’t significantly improve the accuracy suggesting that RF, GBM and SVM are robust enough for millet FCover estimation in such kind of landscape.While the original workflow we proposed in this study need to be confirmed by adding data from the 2022 cropping season, the results obtained show promising opportunities for improving the crop monitoring in heterogeneous landscapes. The next step will be to better understand the influence of trees on the millet FCover, at the field scale and at the landscape scale.
Emissions Inventory of Air Pollutants from Anthropogenic Sources in Jakarta
Authors: Lestari Puji , Arrohman Maulana Khafid , Damayanti Seny , Klimont Zbigniew
Published: February 2023

Emission inventory is an important tool for air quality management. Jakarta as a capital city of Indonesia has a very high air pollution as a result of urban activities from various anthropogenic sources. This study aims to conduct emission inventory and emission spatial distribution of NOX, CO, PM2.5, PM10, NMVOC, BC, and SO2 from anthropogenic sources in Jakarta from 2015 to 2030, using 2015 as a baseline year. The results from this study can be very important to improve the emission data for Jakarta and contribute to the global emission model. This result can also be used for air quality management and lesson learnt cases for other regions in South East Asian countries.   Emissions of these pollutants were calculated using GAINS (Greenhouse gas Air pollution INteractions and Synergies) model, considering implementation of emission standards for transport and stationary combustion sources as well as policies stimulating accelerated electrification of vehicle fleets and vehicle scrapping programs. The impact of current policies to emission reduction was also evaluated in this study. The total 2015 emissions of NOX, CO, PM2.5, PM10, NMVOC, BC and SO2 were estimated at around 53 kt, 144 kt, 4.6 kt, 6 kt, 48.6 kt, 1.2 kt, and 20 kt, respectively. The biggest contribution for NOx, CO, BC and NMVOC emissions originated from road transportation sector which contributed about 57%, 93% and 75%, 96% respectively, while for SO2, industrial combustion contributed about 67%. Heavy duty vehicles contribute the most NOx and BC emissions in the transport sector, while motorcycles emit the most CO. Meanwhile PM2.5 and PM10 in Jakarta are mostly emitted from road transportation and industrial combustion sectors, which contributed around 43%-46% for each sector. Heavy duty vehicles were still the highest contributor of PM2.5 emission in the transport sector. In addition to air pollutants, GHG (CO2 eq) emission was also calculated in this study and the results indicating that the main contributor in 2015 were road transport  and power & heating plant which contributed 34% and 32 % respectively.  Based on emission spatial distribution, the highest concentration of all pollutants was found in the central of Jakarta, where traffic activities are very busy. Policy implementation could effectively reduce pollution levels in Jakarta. The accelerated implementation of electric vehicles, stringent emission standards, and transport management measures like electronic road pricing could significantly contribute to the reduction of PM2.5, PM10 as well as BC.Keywords: Emission inventory, pollutants, power plant, industry, residential and commercial, PM2.5, NOx, SO2, NMVOC, GAINS. 
Method to identify and quantify the effect of climatic and non-climatic drivers on river discharge in Europe
Authors: Collignan Julie , Polcher Jan , Quintana Seguí Pere , Bastin Sophie
Published: February 2023

To predict and manage the evolution of water resources is a high stake for society in the context of climate change and largely managed rivers. A first step in this endeavour is to be able to determine in the past records which of both processes has dominated changes.We propose an innovative way to detect and quantify the changes in river discharge due to climate processes or to non climatic factors over the past century for European catchments. The Land surface model (LSM) ORCHIDEE forced with a century long climate data set is used to simulate the complex hydrological response of natural catchments to change in climatic variables. The Budyko framework is applied with a time-moving window to decompose the direct discharge response to changes in precipitation P and potential evapotranspiration PET and the indirect response due to climate induced changes in the evaporation efficiency of the watersheds. We then apply the same methodology to discharge observations from gauging stations over Europe. It enables to highlight the areas where the model misrepresents (or omits) important catchment processes and where non-natural changing factors impacting the watershed’s apparent evaporation efficiency significantly contribute to trends in the observed discharge over the century. Results over Europe show that long-term changes and variability in discharge due to climate processes are dominated by changes in P. The second main climatic driver is PET except over the Mediterranean area where water is more limiting and where intra-annual changes in the distribution of P outweigh the effect of PET trends on discharge changes. Over most catchments however and mostly in southern Spain, the changes due to factors not accounted for in the "natural" system dominate over the  century. When the focus is on decadal periods, the effect of non-climatic factors is still significant but small compare to the high effect of climate variability. Attempts to attribute non-climatic changes in the catchments evaporation efficiencies are presented. For instance, good correlations are found  between changes in the evaporation efficiency of Spain catchment with the evolution of water stored in dams showing that it is a reliable indicator of the effect of human activities on the hydrological changes of watersheds in that area. Adding the effect of land-use and land-cover changes in the current implementation of the LSM has no significant effects on the hydrological behaviour of the watersheds at the studied scale of this study. Many processes especially related to human factors impact the watershed’s apparent evaporation efficiency, often with complex and inter-correlated feedback effects and further studies are needed to better attribute the non-climatic trends detected. Further developments in LSM would allow to better include these factors. 
Definition of physically-based regional soil moisture-rainfall thresholds for the assessment of landslide hazard
Authors: Ciabatta Luca , Galeazzi Sara , Ponziani Francesco , Berni Nicola , Camici Stefania , Brocca Luca
Published: February 2023

Landslides are one of the most dangerous natural hazards, causing every year fatalities, considerable damage and relevant economic losses. Early warning systems (EWS) for rainfall-induced landslides represent an useful tool for mitigating the impact of such hazard. Traditionally, EWS are based on physically-based models or on empirical relationships between rainfall and landslide occurrence.With the aim of taking into account the hydrological settings within the slope, the Umbria Regional Civil Protection Service started in considering also the soil moisture conditions as triggering factor during the daily analysis of shallow landslide hazard. The historical analysis of landslide events leaded to the definition of a set of soil moisture-based thresholds.By analyzing the soil saturation conditions before and after the rainfall event (by using a hydrological model), it has been seen that most of the activations occurred when the soil reached saturation. This hypothesis has been validated by performing a historical analysis on more than 500 landslides occurred during the period 1990-2022. In this work, we took advantages of this finding and proposed an improvement of the current thresholds that considers the amount of rainfall needed by the soil to reach saturation, and hence, the slope instability. The amount of rainfall needed to reach saturation has been calculated through the definition of soil hydraulic parameters and the saturation degree at the start of the rainfall event. Then, if the fallen rainfall is higher than the critical value needed to reach saturation, an alarm is issued. The obtained threshold is based on soil characteristics and it is independent by the input data (no need for recalibration or threshold adjustment). The proposed methodology is able to identify correctly most of the proposed events (>70%) with a very limited amount of false alarms (4%) considering all the rainfall events occurred during the 1990-2022 period.Further analyses are required for a better definition of the soil hydraulic parameters and the rainfall events but the obtained results confirmed the added value of using soil moisture conditions as triggering factor for shallow landslides activation.
Simulation of Hourly Precipitation over the Tibetan Plateau by Regional Climate Dynamical Downscaling Simulations with Different Resolutions
Authors: Jiang Haojun , Gao Yanhong
Published: February 2023

The spatial and temporal distribution characteristics and changes of summer precipitation over the  Tibetan Plateau(TP) is quite complicated, so it is an urgent problem to simulate the precipitation over the plateau accurately. Due to the improved resolution, dynamical downscaling modelling(DDM) at kilometer scale has shown certain value-added effects in the simulation of water vapor transport and the triggering of convection over the Tibetan Plateau, but it may still not be sufficient to simulate the precipitation characteristics of mountain observations. In this study, a DDM at 4 km resolution and a DDM at 28 km resolution were conducted in summer (June 1 to August 31, 2014). Based on the station observation datasets, the hourly precipitation changes of ERA5 reanalysis data and the above simulation results with different resolutions were evaluated. It indicates that CPM has a significant advantage in simulating precipitation in daytime precipitation simulation, but it underestimates the precipitation at night obviously, while the performance of ERA5 and DDM show acceptable performance.Meanwhile, this situation varies greatly among different basins on TP, which is worth further analysis. The key of this study is to to fully consider small-scale physical processes and the turbulence problems involved in boundary layer processes on the basis of 4km resolution simulation, so as to explore the optimal resolution of hourly precipitation simulation over TP. The physical mechanism behind this is related to the different feedback of scale interactions caused by different resolutions, which may involve the different characterization of terrain and underlying surface features.
Steady states and bifurcation diagram for the Permian-Triassic paleogeography
Authors: Ragon Charline , Vérard Christian , Kasparian Jérôme , Brunetti Maura
Published: February 2023

The climate relaxes toward a steady state under a permanent inhomogeneous forcing from solar radiation and dissipative mechanisms. As a highly nonlinear system, the Earth’s climate can exhibit multiple steady states at a given forcing. Multistability has been observed in numerical models of different complexities, including fully coupled general circulation models with an aquaplanet configuration (Ragon et al. 2022), and we show here multistability also applies for the Earth in deep time.
We use the MIT general circulation model in a coupled atmosphere-ocean-sea ice-land configuration to perform simulations at a constant forcing i.e., fixed solar constant and atmospheric partial pressure of CO2. We let the system relax for thousands of years, which is the typical timescale of ocean dynamics. Considering the paleogeography of the Permian-Triassic reconstructed after PANALESIS (Vérard 2015), we find multiple competing steady states, representing alternative potential climates for that period.
Then, we construct the corresponding bifurcation diagram by varying the atmospheric CO2 content. This allows us to identify the stability range of each steady state, the position of tipping points and the required conditions for the system to shift from one state to another, which may help to understand the climatic oscillations observed, e.g., during the Early Triassic.
References
Ragon C., Lembo V., Lucarini V., Vérard C., Kasparian J. & Brunetti M., Robustness of competing climatic states. Journal of Climate, 35, 2769-2784. (2022)
Vérard C., PANALESIS: Towards global synthetic palæogeographies using integration and coupling of manifold models. Geological Magazine, 156, 320-330. (2015) 
Enhanced High-Latitude Concurrent Blockings Cause the Warm Arctic-Cold Continent Pattern
Authors: Zhao Liang , Qu Jing
Published: February 2023

A rapidly warming Arctic and mild cold mid-latitude continents have been one of the main characteristics of the Northern Hemisphere winter during the last two decades. However, the factors contributing this warm Arctic-cold continent (WACC) pattern remain unclear, although anomalies in blocking highs and the Arctic oscillation (AO) are possible factors. This study revealed that the mode with high-latitude concurrent blockings (HCBs) is more consistent with the WACC pattern than the AO. In the HCB mode, a strong anticyclonic anomalous circulation over the Arctic Circle, excited by the strong HCBs over the Ural Mountains and the North Pacific, changes the polar atmospheric circulation and redistributes both momentum and heat to give a warmer Arctic than in the AO mode. A weak polar night jet and a poleward shift in the subtropical westerly jet result in mild cold mid-latitude continents. However, these features are not seen in the AO mode, which is characterized by cool continents and a warm Greenland. Besides, human activities may also be contributed to the interdecadal WACC because there is an interdecadal increase in the WACC pattern with HCBs in the CMIP6 simulations with human activities. These results suggest that the role of HCBs should be highly paid attention in winter mid-high latitude extreme events in recent decades.
Observing Tropospheric Carbon Monoxide and Ammonia from the Geostationary Interferometric Infrared Sounder (GIIRS) onboard FengYun-4B
Authors: Zeng Zhao-Cheng , Lee Lu , Qi Chengli
Published: February 2023

The Geostationary Interferometric Infrared Sounder (GIIRS) onboard FengYun-4 series satellites is the world’s first geostationary hyperspectral infrared sounder. With hyperspectral measurement covering the carbon monoxide (CO) and ammonia (NH3) absorption windows around 2150 cm-1 and 9150 cm-1, respectively, GIIRS provides a unique opportunity for monitoring the diurnal variabilities of atmospheric CO and NH3 over East Asia. In this study, we develop the FengYun Geostationary satellite Atmospheric Infrared Retrieval (FY-GeoAIR) algorithm to retrieve the CO and NH3 profiles from FY-4B/GIIRS data and provide CO and NH3 maps at a spatial resolution of 12 km and a temporal resolution of 2 hours. The performance of the algorithm is first evaluated by conducting retrieval experiments using simulated synthetic spectra. The result shows that the GIIRS data provide significant information for constraining CO and NH3 profiles. The degree of freedom for signal (DOFS) and retrieval error are both significantly correlated with thermal contrast (TC), the temperature difference between the surface and the lower atmosphere. Retrieval results from one month of GIIRS spectra in July 2022 show that the DOFS for the majority is between 0.6 and 1.2 for the CO total column and between 0 and 1.0 for the NH3 total column. Consistent with retrievals from low-earth-orbit (LEO) infrared sounders, the largest observation sensitivity, as quantified by the averaging kernel (AK), is in the free troposphere for CO and in the lower troposphere for NH3. The diurnal changes in DOFS and vertical sensitivity of observation are primarily driven by the diurnal TC variabilities. This study demonstrates the capability of GIIRS in observing the diurnal CO and NH3 changes in East Asia, which will have great potential in improving local and global air quality and climate research.
On the importance of 3D stress state in 2D earthquake rupture simulations with off-fault deformation
Authors: Thomas Marion , Jeandet Louise , Bhat Harsha
Published: February 2023

During the last decades, many numerical models have been developed to explore the conditions for seismic and aseismic slip. Those models explore the behavior of frictional faults, embedded in either elastic or inelastic mediums, and submitted to a far field loading (seismic cycle models), or initial stresses (single dynamic rupture models). Those initial conditions impact both fault and off-fault dynamics. Because of the sparsity of direct measurements of fault stresses, modelers have to make assumptions about the initial conditions. To these days, Anderson theory is the only framework that can be used to link fault generation and reactivation to the three-dimensional stress field.  In this study, we focus on the initial stresses in 2D plane strain models developed to compute off-fault deformation. It has been demonstrated that initial conditions, in particular the angle between fault and the greatest compressive stress, is of crucial importance for the localization and intensity of off-fault inelastic deformation. However, because those models are performed on a 2D plane, the importance of the out-of-plane stress have never been investigated. We show that it can lead to set up a stress field that is not in agreement with Anderson theory (i.e., modelling a strike-slip fault in a three-dimensional stress field appropriate for reverse faulting). We investigate the influence of initial stresses by comparing equivalent models with “correct” and “incorrect” initial stress fields, keeping constant rupture-related parameters (stress drop, seismic ratio), angle between fault and greatest principal stress, and depth. We first use purely elastic models to study the influence of initial stresses on the assessment of two plastic criteria (Drucker-Prager and Coulomb stress change). We show that setting up the incorrect initial stress field can lead to underestimating the different yield criteria. The error is of the order of magnitude of the dynamic stress drop. Moreover, setting up the incorrect pre-stresses leads to errors in the estimation of potential off-fault failure modes. Then, we explore the influence of pre-stresses conditions on off-fault inelastic deformation. Using two different modelling strategies (a plastic deformation model and a micromechanics model computing dynamic damage), we show that setting up the incorrect stress field can lead to underestimate the size of the damage zone by a factor of 3 to 6 for the studied cases.  Moreover, because of the interactions between fault slip and off-fault deformation, we show that initial stress field influences the rupture propagation. Setting up the correct stress field can significantly slow the rupture, because of the more important quantity of damage induced.
Combining runoff generating mechanisms and the Metastatistical Extreme Value approach to predict extreme floods in catchments with strong discontinuities in the flood frequency curve
Authors: Mushtaq Sumra , Miniussi Arianna , Merz Ralf , Tarasova Larisa , Marra Francesco , Basso Stefano
Published: February 2023

River floods are the most common natural hazards worldwide and accurate flood estimation is crucial for reducing flood risk. Traditional flood frequency analysis relies on the assumption of homogeneity of the analysed floods. However, floods arise from multiple generating mechanisms, such as rainfall on wet and dry soils, rain-on-snow and snow-melt events. Streamflow records may therefore comprise mixtures of events. Ignoring this may cause significant errors in the estimation of flood frequency. The problem is particularly evident in catchments with a discontinuity in the flood frequency distribution, where the rarest floods are significantly larger than the rest of the events in the record. These situations cannot be represented by traditional frequency analyses. Extreme floods may thus occur unexpectedly and produce disproportionate losses and casualties. Here, we propose a practical method to handle the problem of flood frequency estimation in catchments with strong discontinuities in the flood frequency curves.In this work, we focus on rivers among 160 case studies in Germany which show a marked discontinuity in the empirical flood frequency distribution and we use the simplified Metastatistical Extreme Value (SMEV) approach to separately include floods with different generating mechanisms in the estimation of the flood frequency distribution. We extract all the independent ordinary events from daily streamflow records and organize them into two groups according to the key runoff generation processes (rain-on-dry, mixture of rain-on-wet and snowmelt processes). We fit a statistical distribution (either power law or log normal based on the statistical properties of the ordinary events) to each group. Then, we use SMEV to calculate the emerging frequency distribution.Our results show that the proposed approach improves the estimation of the magnitude of floods with long return periods. Considering the mixture of generating processes allows to reproduce the observed discontinuities in the flood frequency curves. Comparison with the standard Generalized Extreme Value distribution shows that the proposed method reduces the estimation bias, especially for large quantiles.This study summarizes the results of the DFG-funded project "Propensity of rivers to extreme floods: climate-landscape controls and early detection - PREDICTED" (Deutsche Forschungsgemeinschaft - German Research Foundation, Project Number 421396820).  
Analyzing Total Suspended Matter variability at the Ebro-Segre river confluence (North-East Spain) by satellite data
Authors: Lacava Teodosio , Albano Felice , Ciancia Emanuele , Filizzola Carolina , Lahsaini Meriam , Mazzeo Giuseppe , Pietrapertosa Carla
Published: February 2023

High-quality inland water is crucial for human life, as well as for preserving the biodiversity of the involved ecosystems and habitats. The implementation of adequate monitoring systems for inland water quality is requested by the EU Water Framework Directive, as well as foreseen within the Sustainable Development Goals of the 2015 Agenda of the United Nations. Ocean-color remote sensing may represent a useful tool to complement ground-based measurements, since it ensures synoptic view as well as a good trade-off between spatial and temporal resolution. Among the water quality parameters that can be retrieved by satellite, Total Suspended Matter (TSM) is one of the most relevant, because its fluctuations can affect light penetration and phytoplankton productivity, thus threatening the ecological status of inland waters. Optical sensors such as OLI (Operational Land Imager) onboard Landsat 8 and 9 and (MSI Multispectral Instrument) on Sentinel 2A and 2B, have already demonstrated their capabilities in providing accurate TSM retrievals with spatial resolution up to 20 and a sub-weekly temporal resolution, especially when jointly used. In this work, the long-term spatiotemporal TSM variability by satellite data has been investigated for a subset of the Segre and Ebro river confluence, just downstream the Mequinenza dam (province of Saragozza, North-East Spain). This area has been studied within the framework of the IDEWA (Irrigation and Drainage monitoring by remote sensing for Ecosystems and Water resources management) project, funded by the EU PRIMA program, to assess the impacts of irrigation activities (including drainage) on water quality within the Algerri Balaguer irrigation district. The assessment of TSM climatology, its inter-annual variability and the identification of potential extreme TSM plumes have been performed also for comparison with river discharge (Q) data (free available by the Confederación Hidrográfica del Ebro), measured close to the Mequinenza dam for the 2015-2022 period and the achieved results will be discussed in this work.
Trends in pit-latrine usage in Malawi and their unintended impacts on groundwater quality
Authors: Hinton Rebekah , Banda Limbikani , Macleod Christopher , Troldborg Mads , Kalin Robert
Published: February 2023

Providing adequate and equitable sanitation to all by 2030 is central to achieving Sustainable Development Goal 6 (SDG6). Pit-latrines provide a low-cost, accessible form of sanitation, there has, therefore, been a significant increase in the rapidly growing Malawian population using pit latrines, largely driven by a reduction in open defecation. Whilst open defecation reduction is critical in managing waterborne pathogens and other contaminants, pit latrines can also result in both microbial and nutrient contamination of groundwater; faecal contamination of groundwater, resulting in contaminated boreholes, has already been documented in Malawi.To forecast the level of pit-latrine usage in Malawi, we evaluate the trends in Malawian sanitary provision using linear modelling to estimate that currently 500,000 people gain access to sanitation in Malawi every year, requiring approximately 93,000 new pit-latrines to be constructed annually to accommodate this shift. The associated increase in pit-latrine density creates a heightened threat of borehole contamination and a key public health concern.We also examine the nature of pit-latrine management and usage, presenting the results of a national survey of over 200,000 sanitary facilities. Whilst pit-latrines are usually associated with faecal contaminants, we found that 82.3% of pit-latrines had materials other than faecal waste deposited including rubbish, plastics, and oils; these present a danger of micropollutant contamination. Furthermore, we find that sustainable practises to manage waste deposited in pit-latrines, such as pit-latrine emptying, have low adoption.Pit-latrine usage is already causing groundwater contamination in Malawi, this will only be exacerbated by our projected increase in pit-latrine usage as Malawi manages a growing population and actively pushes to eliminate open defecation.This research is thanks to research and collaboration with the Government of Malawi with funding by the Scottish Government under the Scottish Government. Climate Justice Fund Water Futures Programme.
Impact of Deforestation in the Maritime Continent on the Madden–Julian Oscillation
Authors: Chang Chuing-Wen June , Lo Min-Hui , Tseng Wan-Ling , Tsai Yu-Cian , Yu Jia-Yuh
Published: February 2023

Deforestation is a major issue affecting both regional and global hydroclimates. This study investigated the effect of deforestation in the Maritime Continent (MC) on tropical intraseasonal climate variability. Using a global climate model with Madden–Julian Oscillation (MJO) simulations, we examined the effect of deforestation over the MC region by replacing the forest canopy with grassland. The results revealed that under constant orographic and land–sea contrast forcing, the modification of the canopy over the MC altered the characteristics of the MJO. We noted the amplification of the MJO and increases in wet–dry fluctuation and the zonal extent. We analyzed more than 100 MJO cases by performing K-means clustering and determined that the continuous propagation of the MJO over the MC increased in 35% and 61% of the total 110 cases in the control and deforestation experiments, respectively. This phenomenon was associated with more substantial vanguard precipitation, increased soil moisture, and a suppressed diurnal cycle in land convection. Furthermore, when the MJO convection was over the Indian Ocean (IO), we observed the enhancement of low-level moisture over the MC region in the deforestation experiment. Grassland surface forcing provides a thermodynamic source for triggering instability in the atmosphere, resulting in low-level moisture convergence. The MJO exhibited a stronger energy recharge–discharge cycle in the deforestation experiment than in the control experiment, and this difference between the experiments enlarged from the IO to MC. 
On the realism of Arctic Ocean transports in CMIP
Authors: Winkelbauer Susanna , Mayer Michael , Haimberger Leopold
Published: February 2023

This contribution evaluates key components of the Arctic energy budget as represented by the Coupled Model Intercomparison Project Phase 6 (CMIP6) against reanalyses and observations.The Arctic regions are characterized by a net energy loss to space, which is balanced by northward heat transports in atmosphere and ocean. Mean and variability in the oceanic northward heat transports have major impacts on the state and change of the Arctic Ocean and sea ice. Therefore, an accurate representation of oceanic transports in climate models is a key feature to realistically simulate the Arctic climate. However, the nature of curvilinear ocean model grids and the variety of different grid types used in the CMIP ensemble, make the calculation of oceanic transports on their native grids difficult and time consuming. We developed new tools that enable the precise calculation of volume, heat, salinity and ice transports through any desired oceanic sections or straits for a large number of CMIP6 models as well as ocean reanalyses. Our tools operate on native grids and hence avoid biases that often arise from interpolation to regular grids. Those tools will be made available as open-source Python package enabling easy and effortless calculations of oceanic transports.In the work presented here, we use the newly developed tools to compare oceanic heat transports (OHT) through the main Arctic gateways from CMIP6 models and reanalyses to those gained from observations and analyze them concerning their annual means, seasonal cycles and trends. We find strong connections between the Arctic’s mean state and lateral OHT, with variations in OHT having major effects on the sea ice cover and ocean warming rate.Results help us to understand typical model biases. For instance, many models feature systematic biases in oceanic transports in the Arctic main gateways, e.g., some models feature to high sea ice extents due to the underestimation of heat transports entering the Arctic through the Barents Sea Opening. Using those results it is possible to generate physically based metrics to detect outliers from the model ensemble, which may be useful in reducing the spread of future projections of Arctic change.
The ice-cavity feedback in an Earth system model
Authors: Song Pengyang , Scholz Patrick , Knorr Gregor , Sidorenko Dmitry , Timmermann Ralph , Lohmann Gerrit
Published: February 2023

The melting of the Antarctic ice shelves becomes critical in a warming climate. However, the ocean component of climate models do not consider the effect of the Antarctic ice-shelf cavities. Here, we implement ice-shelf cavity features into the new AWI Earth system model (AWI-ESM2) based on unstructured meshes allowing for varying resolution in a multi-scale approach. We create a global mesh explicitly resolving the Antarctic ice-shelf cavities and evaluate the effect of the cavities under global warming scenarios. The new mesh provides a more realistic freshwater input into the Antarctic coast and the Southern Ocean. In an extreme warming climate scenario, the melting of the Antarctic ice shelves gets stronger by a factor of ~3, affecting the North Atlantic salinity and the overturning circulation. We conclude that the incorporation of ice-cavity feedback is essential to study the past, present, and future. Our approach might be seen as a prototype for the next phase of the Coupled Model Intercomparison Project.
Does the Middle Miocene rise of the Greater Himalaya cause the slow down of Southern Tibet exhumation?
Authors: Thiede Rasmus , Scherler Dirk , Glotzbach Christoph
Published: February 2023

The Himalaya is the highest and steepest mountain range on Earth and forms today efficient north-south barrier for moisture-bearing winds. 1D-thermokinematic modeling of new zircon (U-Th)/He bedrock-cooling ages and >100 previously published mica 40Ar/39Ar, zircon and apatite fission track ages from the Sutlej Valley document a consistent rapid decrease in exhumation rates that initiated at ~17-15 Ma across the entire Greater and Tethyan Himalaya and the north-Himalayan Leo Pargil dome. We observe a rapid decrease from >1 km/Myr to <0.5 km/Myr. Simultaneous changes in the hanging and footwall of major Miocene shear zones suggest that cooling is associated to surface erosion and not due to tectonic unroofing such as due to E-W extension. We explain the middle Miocene deceleration of exhumation with major tectonic reorganization of the Himalayan orogen, probably coincident with the onset of basal accretion, which resulted in accelerated uplift of the Greater and Tethyan Himalaya above a mid-crustal ramp and the establishment of a new efficient orographic barrier. The period of slow exhumation in the upper Sutlej Valley coincides with a period of internal drainage in the south-Tibetan Zada Basin farther upstream, which we interpret to be a consequence of tectonic damming. Exhumation rates in the upper Sutlej Valley accelerate again at ~5-3 Ma, and allowed the Sutlej River to re-establish external drainage of the Zada Basin. Comparison with other data from the Himalaya and Southern Tibet along strike suggests that by ~15 Ma, southern Tibet was high, located in the rain shadow of the High Himalaya and eroding slowly for at least 10 Ma, before erosion accelerated again by ~5-3 Ma, most likely due to climatic changes. Our new finding document that the location of tectonic deformation processes controls the first order spatial pattern of both climatic zones and erosion across the orogen. Therefore, we think that the rise of Greater Himalaya is linked to the deceleration of exhumation in Southern Tibet.
Long-range Lightning Interferometry (A Simulation Study)
Authors: Bai Xue , Fullekrug Martin
Published: February 2023

Traditional long-range lightning detection and location networks use Time-of-Arrival (TOA) differences, and a single timestamp to locate lightning events. For long propagation distances, the amplitude of ground waves decays faster with distance than sky waves as a result of the ground conductivity and the effects of Earth curvature (Caligaris et al., 2008, Cooray, 2009, Hou et al., 2018). This can lead the skywaves to interfere with their large amplitudes when locating lightning.Coherency, which is short for phase coherency of the analytic signal, is used here, which exhibits lightning characteristics (Bai & Fullekrug, 2022). This work introduces a simulation study to lay the foundation for new lightning location concepts. A novel interferometric method using coherency is presented here, which expands the use of more data points of recorded lightning sferics to map the lightning into an area in a long-range network. In this map, each pixel corresponds to a lightning location with different coherency and time of arrival differences, simulated by shifting the complex lightning waveforms. In long-range networks, the coherency of the 1st skywave is larger than the ground wave, and it is difficult to distinguish them due to the short time delay between them. One solution is to use a small network so that the recorded waveforms are associated with short propagation distances which can eliminate the interferences caused by the first skywave. Another solution is to filter the data such that a lightning waveform is represented by an impulse. In this case, only one maximum coherency area exists for each event at the lightning occurrence time.In the future, the data collected with a real-time lightning detection network will be analysed to map the lightning events using the complex interferometric method for use in long-range lightning location networks. ReferencesBai, X., & Füllekrug, M. (2022). Coherency of Lightning Sferics. Radio Sci., 57(5), e2021RS007347. doi: 10.1029/2021rs007347Caligaris, C., Delfino, F., & Procopio, R. (2008). Cooray–Rubinstein Formula for the Evaluation of Lightning Radial Electric Fields: Derivation and Implementation in the Time Domain. IEEE Trans. Electromagn. Compat., 50(1), 194-197. doi: 10.1109/temc .2007.913226Cooray, V. (2009). Propagation Effects Due to Finitely Conducting Ground on Lightning-Generated Magnetic Fields Evaluated Using Sommerfeld’s Integrals. IEEE Trans. Elec-tromagn. Compat., 51(3), 526-531. doi: 10.1109/temc.2009.2019759Hou, W., Zhang, Q., Zhang, J., Wang, L., & Shen, Y. (2018). A New Approximate Method for Lightning-Radiated ELF/VLF Ground Wave Propagation over Intermediate Ranges. Int. J. Antennas Propag., 2018(6), 1-10. doi: 10.1155/2018/9353294
Geochemical and palynological evidence for a two-phased end-Triassic mass extinction in the Paris Basin (Lorraine, France)
Authors: Kuhlmann Natascha , van de Schootbrugge Bas , Thein Jean , Franz Sven-Oliver , Colbach Robert
Published: February 2023

The Triassic-Jurassic transition, from the Norian to the Hettangian (corresponding to the Rhaetian), was a critical timespan marked by a series of global environmental perturbations, most notably the end-Triassic mass extinction event (201.6 Ma). Here, we present palynological, mineralogical, geochemical, and sedimentological data obtained from new core material spanning the Upper Triassic to Lower Jurassic in the northeastern Paris Basin. Together, these data give new insights into the link between terrestrial and marine extinctions, and their respective driving mechanism. The Boust core (Lorraine, France) provides a complete succession of marginal marine sedimentation. The δ13Corg record from Boust reveals two major C-isotope excursions that, based on the available biostratigraphy, correspond to the Negative-1 (Marshi) and Negative-2 (Spelae) negative isotope excursions. While the Marshi excursion is marked by high abundances of dinoflagellate cysts, the Spelae excursion is marked by an influx of acritarch species. The two excursions bracket an interval of strongly diminished tree pollen abundances and proliferation of fern spore taxa, marking the extinction interval associated with the ETME and forming an equivalent to the Triletes Beds in Germany. This subdivision is confirmed by sedimentological and geochemical results as well as by lithological changes, which are reflecting the development of the depositional environment during the Rhaetian.
Connectivity analysis applied to mesoscale eddies in the Western Mediterranean basin
Authors: Aulicino Giuseppe , Cotroneo Yuri , Celentano Paolo , Perilli Angelo , Pessini Federica , Olita Antonio , Falco Pierpaolo , Sorgente Roberto , Ribotti Alberto , Fusco Giannetta , Budillon Giorgio
Published: February 2023

The Western Mediterranean basin (WMED) is characterized by the presence of energetic and dynamic mesoscale cyclonic and anticyclonic eddies. They mainly originate along the Algerian and the Northern currents and have a large influence on the basin circulation. Eddies can last for months, with longer lifetimes associated with the anticyclones, which can move far from their areas of origin. As they partially isolate and transfer water masses, they also have an impact on water properties (physical, chemical and biological), pollutant’s dispersion and transport of eggs, larvae and planktonic organisms. In this study, a connectivity analysis method is applied to the anticyclonic eddies (AEs) identified by an automated hybrid detection and tracking algorithm south of 42° N in the WMED. The same methodology is also applied to the trajectories of Lagrangian surface drifters available in the study area. The purpose is to highlight the connections between different areas of the basin linked to eddy activities in addition to the connectivity due to the mean surface circulation. Drifter data analysis showed that all the WMED sub-basins are strongly interconnected, with the mean surface circulation allowing a shortcut connection among many areas of the basin. The connectivity analysis of the AEs tracks shows that although AEs are ubiquitous in the WMED, their connectivity is limited to well-defined regions, depending on their origin location. Three main regions: the south-western, the south-eastern and the northern parts of the basin are characterized by AEs recirculation, with sporadic export of eddies to the other WMED zones.