bluuebunny/crossref_metadata_2025 huggingface dataset:
The Jovian ionospheric conductivity derived from a broadband precipitated electron distribution
Authors: Sicorello Guillaume , Bonfond Bertrand , Gérard Jean-Claude , Grodent Denis , Gkouvelis Leonardos , Gladstone Randy , Salveter Annika
Published: February 2023

The Pedersen ionospheric conductivity at Jupiter can be computed using a precipitated electron flux either obtained by direct in situ measurements or inferred from UV auroral spectra (Gérard et al., 2020). In the latter case, a mono-energetic distribution was used to represent the electron flux. However, based on the Juno spacecraft recent findings, it appears that the impinging electron flux is best approximated with a broadband distribution (Mauk et al., 2017; Salveter et al., 2022). In this study, we estimate the impact of such a distribution on the conductivity. In particular, we examine the ratio between the Pedersen conductances computed with a mono-energetic and with a broadband distribution, which can be modelled with a kappa distribution. A similar methodology as in Gérard et al. (2020) is followed to compute the conductances. The altitude distributions of H, H2 and CH4, included in the atmosphere model, are taken from Grodent et al’s (2001) model.Among other results, we find that the ratio between conductances depends on the electron mean energy of the precipitating electrons population. For a mono-energetic distribution, an optimal energy exists, around 30-40 keV, for which the conductance arising from the precipitation is maximum. If the mean electron energy is well below this optimal energy, the conductance calculated for a kappa distribution is enhanced compared to the mono-energetic case because part of the electron energy distribution reaches this optimal level. The conductance is also underestimated for a mono-energetic electron precipitation well above the optimal value. The opposite trend is observed around the optimal energy as most of the electrons of the broadband distribution have either lower or higher energies, while all electrons of the mono-energetic distribution have an energy close to the optimum.In conclusion, compared to a realistic broadband electron distribution on Jupiter, a mono-energetic distribution tends to overestimate the conductivity for mean energies in the 7 – 450 keV range and to underestimate it outside this range. In the future, this new relationship between the mean energy and the conductivity will be used to update the conductance maps built from the data from Juno.References:Gérard, J.‐C., Gkouvelis, L., Bonfond, B. et al. (2020). J. Geophys. Res Space Phys., 125, e2020JA028142. https://doi.org/10.1029/2020JA028142.Grodent, D., Waite, J. H. and Gérard, J.-C. (2001). J. Geophys. Res., 106 (A7), 12933–12952. https://doi.org/10.1029/2000JA900129.Mauk, B., Haggerty, D., Paranicas, C. et al. (2017). Nature, 549, 66–69. https://doi.org/10.1038/nature23648.Salveter, A., Saur, J., Clark, G. et al. (2022). J. Geophys. Res Space Phys., 127, e2021JA030224. https://doi.org/10.1029/2021JA030224.
Classification of Atmospheric Circulation Patterns That Trigger Rainfall Extremes in the Sudan-Sahel Region
Authors: Rauch Manuel , Bliefernicht Jan , Laux Patrick , Kunstmann Harald
Published: February 2023

A better understanding of the rainfall variability and extremes in tropical regions is crucial for the development of improved statistical and numerical approaches used for climate research and weather prediction. In this study, we present a novel fuzzy rule-based method for classifying atmospheric circulation patterns relevant to heavy rainfall in the Sudan-Sahel region over West Africa. In the first step, we determine large-scale atmospheric patterns to describe important seasonal features of the West African Monsoon like the movement of Saharan Heat Low over the African continent. In the second step, meso-scale monsoon patterns are classified to better describe rainfall variability and extremes during the monsoon period. In addition to a comprehensive predictor screening using more than 30 variables at different atmospheric levels, a detailed sensitivity analysis is performed, which aims to improve the transferability of the classification approach to an independent dataset. Furthermore, crucial aspects of the methodological development of fully automatic classification approaches are addressed. Using mean sea level pressure and stream function fields (700hPa) as final predictor variables, we identified 23 circulation patterns as robust solution to represent key atmospheric processes and rainfall variability in the study region. The two wettest patterns are distinguished by an enhanced Saharan Heat Low and cyclonic rotation near the study region, suggesting the presence of a tropical wave trough and triggering about 50% of the rainfall extremes on 6.5% of the days. The identified atmospheric circulation patterns are currently used to develop a variety of improved statistical approaches for this challenging region, such as pattern-dependent bias correction, geostatistical interpolation, and simulation. 
Advancing frontier knowledge of the solid earth by providing access to integrated and customized services: the Geo-INQUIRE project
Authors: Cotton Fabrice , Strollo Angelo , Pedersen Helle , Crowley Helen , Wiemer Stefan , Haslinger Florian , Urvois Marc , Schmittbuhl Jean , Lorito Stefano , Babeyko Andrey , Bailo Daniele , Michalek Jan , Lange Otto , Quintero Javier , Festa Gaetano , Murphy Shane , Majdanski Mariusz , Christadle Iris , Prestes Mateus , Weege Stefanie
Published: February 2023

Modern scientific endeavours already have the capacity to call upon a vast variety of data, often in huge volumes. However, the challenge is not only how to make the most of such a resource, but also how to make it available to the wider scientific community, especially for encouraging curiosity-driven research. Fifty-one institutions from 13 countries are currently working together in the Geo-INQUIRE (Geosphere INfrastructure for QUestions into Integrated REsearch) project.The main goal of this new project is to enhance, give access to, and make interoperable, key datasets of the Geoscience community. This will include "big" data streams and high-performance computing codes which are critical to studying the temporal variation of the solid Earth, forecasting multi-hazards, evaluating Georesources and the analysis of the interface between the solid Earth as well as oceans and atmosphere.  About 150 access points – both on-site and virtually are involved. Transnational Access (TA, both virtual and on-site) will be provided at six test beds across Europe: the Bedretto Laboratory, Switzerland; the Ella-Link Geolab, Portugal; the Liguria-Nice-Monaco submarine infrastructure, Italy/France; the Irpinia Near-Fault Observatory, Italy; the Eastern Sicily facility, Italy; and the Corinth Rift Laboratory, Greece.Several European Research Infrastructure Consortia take part, namely the European Plate Observing System (EPOS) for solid Earth and geodynamics observations, the European Multidisciplinary Seafloor and Water Column Observatory (EMSO) for deep-sea and coastal observations, and ECCSEL for CO2 capture, utilization, transport, and storage, and geoenergy. This 16 million Euro project started in October 2022, within the Horizon Europe Infrastructure program of the European Union.The presentation will briefly describe the project and give examples of curiosity-driven research topics which will be made possible through such a multi-disciplinary project. We will finally present the challenges and efforts made to comply with FAIR principles and accompany the dissemination of the data with innovative and cross-disciplinary training activities.
Overview of the 3GM experiment on board the JUICE mission
Authors: De Marchi Fabrizio , Cappuccio Paolo , Mitri Giuseppe , Iess Luciano , Di Benedetto Mauro
Published: February 2023

The ESA’s Jupiter Icy moons Explorer (JUICE) L-class mission is devoted to the study of the Jovian system.It will be launched in 2023 and, after an 8-year cruise phase (with 3 gravity assists to Earth and 1 to Venus), will start a tour of the Galilean moons that will last 3.2 years.The onboard Geodesy and Geophysics of Jupiter and the Galilean Moons (3GM) radio science experiment will accomplish a detailed study of Europa, Ganymede and Callisto thanks to a state-of-the-art radio tacking system. 3GM will rely on a multi-frequency link enabled by two onboard units: the Ka-band Transponder (KaT) payload (establishing a full 2-way link in Ka band) and the Deep Space Transponder (DST), enabling 2-way coherent X/X and X/Ka link used for telemetry and telecommand. The multi-frequency link allows accurate measurements of range (≈1-4 cm @60s) and range rate (≈0.003 mm/s @1000s) at nearly all Sun-probe-Earth angles.The data achieved during the tour phase (2 flybys at Europa and 21 flybys at Callisto) will be used to estimate the Europa’s quadrupole gravity field and Callisto’s static gravity field to at least degree and order 7 and its tidal Love number k2 with an accuracy of ~0.06 [1]. This will allow 3GM to detect the presence or absence of a subsurface ocean underneath the ice shell of Callisto.At the end of the tour phase, JUICE will be the first spacecraft to orbit around and icy satellite, allowing a comprehensive study of the moon. The Ganymede 9-month orbital phase is composed of a 5-month elliptical orbit followed by a 4-month circular orbit at 500 km of altitude (GCO-500). The mission could be extended for a 200 km altitude campaign if the residual propellant will be sufficient to decrease the orbital radius.Range and Doppler data achieved by 3GM during the GCO-500 will be used to infer the static (up to degree 35-45) gravity field, the rotational state, and the tidal response of Ganymede.Ganymede’s k2 is subject to time-varying tides due to Jupiter, Io, Europa and Callisto. In particular, the Ganymede’s gravitational perturbations due to the satellites has a high spectral content. This signal can be used to estimate k2 at a set of frequencies, up to 4d-1. The profile of k2 as a function of the frequency, due to the subsurface ocean, is expected to show a peak at a certain resonance frequency, its value being strictly related to the ocean’s depth. We show that the accuracy of the 3GM radio science data is sufficient to detect the peak, if present, and measure its amplitude. In this case the ocean thickness can be estimated with a 7% uncertainty [2].References:[1] Cappuccio, P.; Di Benedetto, M.; Durante, D.; Iess, L. (2022) Planet. Sci. J. 3 199[2] De Marchi, F.; Cappuccio, P.; Mitri, G.; Iess, L. (2022)  Icarus 386 11515
Decadal variability and predictability of Senegalo-mauritanian upwelling system
Authors: Sylla Adama , Mignot juliette
Published: February 2023

Coastal countries in West Africa heavily rely on the ocean, which is a major source of food and employment. This is mainly due to the presence of coastal upwelling, upward motion of sea water bringing the nutrient-rich deeper waters into the illuminated surface layers in the coastal zone, where they become available for photosynthesis. The resulting phytoplankton production, the base of the food chain, render coastal upwelling the most productive of large marine ecosystems in the world’s oceans. Recently, decadal variability and predictability of coastal upwelling systems has received a lot of attention, since near-term changes of upwelling systems could have a strong impact of living marine resources and hence surrounding countries economy. On this aspect, recent progress has been made in generating near-term (“decadal”) predictions of physical using Earth system models (ESMs). Initialized forecasts have shown significant predictability from 1 to 10 years in advance for climate events showing substantial decadal variability.Our objective here is two-fold: first we investigate the decadal variability of the Senegalo-mauritanian upwelling system (SMUS) in the reanalysis and historical simulations from eleven climate models using indices based on the SST and wind stress and also identify the processes controlling this variability. Second, we exploit the decadal prediction experiments of CMIP6 (DCPP-A), to investigate this upwelling predictability. Our results show that the SMUS is characterized by a strong decadal variability, in part linked to the Atlantic Multidecadal Variability Consequently, the DCPP- A experiment shows strong and generally significant correlation prediction scores at various lead times for the dynamical indices (Ekman transport and Ekman pumping). However, even though coastal SST are also significantly predictable, non-significant ACC scores are found for the thermal upwelling indices. The analysis concludes on trying to qualify and quantify the predictable components of the SMUS and possible applications.
ERA5-Land Data: New Possibilities in Hydrological Modelling and Water Resources Assessment in the Data-Scarce Regions of Sub-Saharan Africa
Authors: Okal Harriette Adhiambo , Molnar Peter , Molnar Darcy , Mantel Sukhmani , Hughes Denis , Tanner Jane
Published: February 2023

Successful application of hydrological models requires data to assess the validity, as well as the inherent uncertainty, of the outputs, most importantly streamflow. In parts of Sub-Saharan Africa (SSA), such data is often lacking. Therefore, it is frequently challenging to find the necessary resources for setting up a robust hydrological model and hydrological monitoring platforms. In data-scarce regions within SSA, ground data required to model and make water resources decisions are not always available and therefore, some form of alternative data sources and simplified modelling approaches are required. In recent years, satellite and climate reanalysis data have been intensely explored for watershed modelling in poorly gauged regions with variables such as precipitation, evapotranspiration, soil moisture, runoff etc. Very good potential is provided by the ERA5-Land dataset which is considered one of the best freely available global products for hydrology given its 0.1° x 0.1° spatial resolution and an hourly to monthly temporal resolution spanning from 1950 till present. Here, ERA-5 Land input on a monthly resolution was assessed in the Berg River Basin, South Africa using the Modified PITMAN model. Total precipitation, runoff, and potential evapotranspiration for each of the basin’s 12 quaternary catchments were retrieved using the Google Earth Engine platform for a study period of 40 years (1981-2021). A validation period of 20 years (1985-2005) was used corresponding to the freely available streamflow data. The assimilation of ERA5-Land precipitation data showed satisfactory results across the basin with the best results in the upstream catchment (G10A) with a 0.634 coefficient of efficiency and 0.404 KGE during the initial run. However, runoff for the downstream catchments (G10K) gave positive biases in high-flow months. This paper gives a detailed analysis of the performance of remotely sensed datasets (ERA5-Land) on catchments with varying climatic, land use and cover, water use, and geomorphological characteristics, therefore, offering a valuable reference for its applications in understanding hydrological processes in different river basins across SSA.
Study of D region ionosphere using incoherent scatter radar measurements
Authors: Thomas Neethal , Kero Antti , Virtanen Ilkka
Published: February 2023

Within the recently started "HPC-approach to Ionospheric Situational Awareness (HISSA)" project, we will re-analyze a comprehensive set of existing European incoherent scatter radar (EISCAT) measurements from Tromso VHF radar carried out since 1990. Our special focus is to extract, for the first time, the spectral information of these experiments for the benefit of better understanding the potential long-term changes in the polar D-region ionosphere. Backscattered spectral parameters are estimated by fitting a theoretical autocorrelation function (ACF) to the observed data by using a Markov chain Monte Carlo (MCMC) inversion approach. The methodology and some preliminary results of the neutral temperature, electron density, and plasma drift velocity at D region altitudes will be presented. The temperature estimates from EISCAT VHF measurements are compared with the simultaneous LIDAR temperature measurements from Tromso. The challenges of D-region temperature estimates from incoherent scatter radar spectral parameters, which is a function of ion-to-neutral collision frequency and ion mass will be discussed in detail.
Wet Snow Mapping in the Karakoram using SAR and Topographic Data
Authors: Li Shiyi , Huang Lanqing , Bernhard Philipp , Hajnsek Irena
Published: February 2023

Wet snow is a critical component of the cryosphere, and its spatial and temporal distribution has important implications for water resources, natural hazards, and the regional climate. However, mapping wet snow in alpine regions such as the Karakoram is challenging due to complex topography, harsh weather conditions, and limited in-situ observations.Previous studies have shown that synthetic aperture radar (SAR) can effectively detect wet snow surfaces using the backscattering ratio between the current and reference images (e.g. the average of summer acquisitions). However, its regional application on a large-scale and complex terrain is hampered, as the ratio value is easily affected by the land cover, local topography, surface roughness, and snow wetness.In this study, we present a new approach for mapping wet snow in the Karakoram using a combination of SAR data and topographic information. The SAR data used in the analysis were obtained from Sentinel-1, and the topographic data included a digital elevation model (DEM), slope angle, and slope aspect ratio. We first used a Gaussian Mixture Model to classify the ratio image of Sentinel-1 into wet snow (WS) and non-wet snow (NWS) classes, then transformed the two classes into a logistic function to characterize the probability of WS based on the backscattering ratio. Secondly, we categorized the image based on the topography and calculated the likelihood of WS for each topographic bin using the WS probability. The joint WS likelihood map was finally obtained by multiplying the WS probability on the backscattering ratio with the WS likelihood on topography, and a binary WS map was generated by setting a threshold on the joint likelihood map.The proposed method was validated using snow maps generated from Sentinel-2 images. Compared with the traditional method of using only the SAR backscattering ratio, our method significantly reduced false negative detections and preserved the high true positive rate, indicating an improvement of robustness and accuracy by combining SAR and topographic data for regional wet snow mapping.This study demonstrates a practical method of merging SAR backscattering features and topographic information for robust regional wet snow mapping in complex mountain ranges. It also provides new insights into the incorporation of different datasets using a probabilistic framework. With the proposed method, the operational monitoring of wet snow distribution in the Karakoram using SAR becomes feasible and reliable.
The influence of deep groundwater flow systems on the Earth’s critical zone
Authors: Czauner Brigitta , Szkolnikovics-Simon Szilvia , Mádl-Szőnyi Judit
Published: February 2023

The depth of the Earth’s critical zone can be questionable especially in thousands meter deep sedimentary basins. Therefore, extension of the critical zone’s usually studied 10s of meters depth considering groundwater flow systems has critical importance. Growing demand for groundwater resources (water, geothermal energy), economic services of the groundwater flow related surface and subsurface processes and phenomena (e.g., groundwater dependent ecosystems, surface salinization), and the potential role of groundwater in the adaptation to and mitigation of the effects of human activities and climate change represent the significance and functions of groundwater flow systems in the critical zone.Regarding the complexity of these flow systems, the primary goal could be the determination of their relative significance in the shallower parts of the critical zone. To this end, the present study proposes a methodology based on the hydrodynamic analysis of measured data to separate flow systems with different driving forces (topography, vertical compaction) and pore pressure regimes (normal or  close to hydrostatic, overpressured, underpressured). These characteristics define the renewability of groundwater resources, the near-surface conditions (e.g., distribution of nutrients, salts and heat, type of vegetation and soils, slope stability, etc.), and the exposure of flow systems to the effects of global and climate change.As a case study, groundwater flow systems of the Great Hungarian Plain (Pannonian Basin, Hungary) were evaluated and characterized by analyzing about 5,800 measured hydraulic data (pre-production static water levels and static formation pressures) in hydraulic head vs. elevation and pressure vs. elevation profiles, tomographic maps, and hydraulic cross sections in combination with the geologic build-up and some surface phenomena (distribution of saline soils and vegetation). As a result, spatial extension and distinct functions in the critical zone were defined for three flow regimes, namely i) the near-surface topography-driven groundwater flow systems, ii) an underlying overpressured regime, and iii) the transition zone of i) and ii). For instance, outstanding significance of the upward flows of saline water from the transition zone was revealed in the generation of saline soils and vegetation.The research was funded by the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21-2022-00014 project.
Eddy covariance CO2 flux data for supporting local climate change mitigation policies.
Authors: Tuzzi Luca , Galvagno Marta , Filippa Gianluca , Cremonese Edoardo , Collalti Alessio , Franzoso Luca , Tomelleri Enrico , Scodellaro Riccardo , Sironi Laura , Colombo Roberto
Published: February 2023

Under the Paris Agreement, countries are encouraged to preserve and enhance existing carbon sinks, especially forests, thereby including the LULUCF (Land Use, Land Use Change and Forestry) sector in international climate mitigation targets. In particular, Europe has set the target to reach climate neutrality, i.e. a balance between anthropogenic emissions by sources and removals by sinks, by 2050. A prerequisite to reach these goals is an accurate and credible estimation of both these large fluxes. However, recent works highlighted the uncertainty related to the quantification of the land sector mitigation potential, one of the most challenging emission sectors. Moreover, the definition of climate mitigation policies often occur at the local level, where details on CO2 removals from forests and other land uses are traditionally lacking. Indeed, local authorities  (e.g. cities and Regions) can be more effective in the transition to a sustainable economy compared to higher level authorities such as Nations.
In this study, we tested a data-driven method based on eddy covariance (EC) data to quantify the current LULUCF role to the regional carbon sink of the Aosta Valley Region (Italy), by the integration of different approaches. Our model is based on eddy covariance measurements of CO2 fluxes, MODIS NDVI (250m), daily gridded meteorological variables at 100m spatial resolution, and a land cover map at 250m spatial resolution. A Random Forest model was used to up-scale the point eddy covariance data to the Regional level, by testing different sets of drivers (air temperature, VPD, Snow (presence/absence), NDVI, solar radiation,...). Our model was then compared to independent data derived from the National Forest Inventory (NFI), and a process-based model. Preliminary results show that forests and other ecosystems of the Region remove nearly 70% of the total anthropogenic emissions in this area. The discrepancies between the different methods will be discussed by exploring the different advantages and flaws and the spatio-temporal variability of the different approaches. Such an assessment of the local carbon budget and its uncertainties will provide a solid base for Climate-smart management of the territory and thus for reaching the carbon neutrality targets.
Evaluation of factors that led to the 1967 paraglacial slope failure at Grewingk Lake and Glacier, Alaska
Authors: Lemaire Emilie , Dufresne Anja , Hamdi Pooya , Higman Bretwood , Amann Florian
Published: February 2023

The interaction between glacier retreat and rock slopes has gained considerable attention in the past years due to climate change. Glaciers shape mountain slopes and can daylight zones of weakness as they recede. Glaciers can act as a preparatory factor or trigger for slope failure. A retreating glacier at the slope's toe is often cited as the cause of failure. However, the relationship between glacier retreat and rock-slope stability is much more complicated, particularly for landslides that lack an explicit trigger. We studied a paraglacial slope failure at Grewingk Lake and Glacier in southcentral Alaska, United States. The collapse occurred on October 14, 1967, with no specific trigger, such as heavy rain or seismic activity on the day of the event. Grewingk Glacier is a lake-terminating glacier that has experienced and continues to experience rapid retreat, as have most glaciers around the world. The rapid retreat and the location of the glacier at the time of the collapse could lead to the conclusion that this was the cause of the collapse. However, a thorough examination of the structural geology of the slope and processes that could contribute to reduce the slope stability showed that the retreat of the glacier is only part of the tale. The structural preconditioning, together with an accumulation of seismic activity and daylighting fracture planes progressively contributed to the slope's destabilization. Our study emphasizes the value of examining the temporal trends of paraglacial rock-slope failures in situations in which there was no evident trigger at the time of the collapse.
Fast acidification conveyed by the Gulf Stream to the North Atlantic
Authors: Carracedo Lidia I. , López-Mozos Marta , Le Bihan Caroline , Álvarez Maria J. , Fajar Noelia M. , Asselot Rémy , Bates Nick
Published: February 2023

Since 1750s human industrial activities have emitted large amounts of CO2 into the atmosphere, increasing the atmospheric CO2 content to unprecedent levels. About a quarter of this exccess of carbon (namely anthropogenic carbon, Cant) is absorbed by the ocean, which acts as a major net Cant sink. Changes in the inorganic carbon chemistry of sea water due to the invasion of Cant - increasing (decreasing) concentration of hydrogen ions, H+ (carbonate ions, CO32−) - are referred to as ocean acidification (OA). The North Atlantic is the oceanic region with the highest storage of Cant per area, closely linked to the Atlantic meridional overturning circulation and subpolar winter deep convection. As a result, it is also the main region where both upper-ocean Cant and fast OA signals are tranferred to deeper levels. Yet, it is still uncertain how much of this signal originates (locally) at these high latitudes or is conveyed (remotely) from the subtropics; or what are the driving mechanisms regulating its lateral vs vertical transfer at different temporal scales. Here we present the preliminary data and results of the CARING (Carbon irrigation in the Noth Atlantic by the gulf Stream) project to i) provide a contemporary assessment of the OA rates conveyed poleward by the Gulf Stream, and to ii) elucidate its role as far-field control to the North Atlantic OA. Our results of in situ pH data over the first 2000 dbar of the water-column, in combination with historical GLODAP data, show the pH decline to be the highest at the surface (subtropical waters down to
Glacier extents in Peru and Bolivia are overestimated in RGIv6 by 27%
Authors: Paul Frank , Rastner Philipp
Published: February 2023

Glaciers in the tropical Andes of Peru and Bolivia are important but rapidly declining water resources. Precise knowledge of their extent is thus mandatory for calculation of their volume, area changes and mass balance. Due to wrongly mapped seasonal snow, the glacier outlines currently available from the widely used RGIv6 are often too large, resulting in errors for change assessment and volume estimation. Apart from snow cover, also frequent cloud cover and shadows cast by the steep terrain make glacier mapping in this region challenging.For this study, we have mapped all glaciers in Peru and Bolivia using cloud-free Landsat TM scenes from 1998 and Sentinel-2 scenes from 2020. In both years seasonal snow off glaciers was largely absent. Glacier extents were mapped with a standard band ratio (red/SWIR) and a scene specific threshold value. Wrongly classified lakes and missing debris cover were manually corrected, the latter also by using the very high-resolution satellite images available in the ESRI Basemap. The Copernicus DEM GLO-30 was used to derive new drainage divides and topographic information for each glacier.In total, we mapped 3586 glaciers larger than 0.01 km2 covering an area of 1747 km2 in 1998. This is 419 km2 or 20% less than the 2166 km2 in RGIv6. As glacier outlines in RGIv6 are from 2000 to 2009 and most area change studies found continuous and strong area decrease over this period, a ‘back-calculation’ of all glacier areas to the year 1998 with an annual shrinkage rate of 1% gives a mean area overestimation of 27% for 1998. This value varies regionally and is smaller in the Cordillera Blanca and much larger (>50%) in other regions. The related modelled glacier volumes for these regions are thus also overestimated. From 1998 to 2020 glaciers have lost 23% of their area (-1% per year).
Candidates for downstream jets at interplanetary shocks
Authors: Hietala Heli , Trotta Domenico , Wilson III Lynn , Fedeli Annamaria , Vuorinen Laura
Published: February 2023

Localized dynamic pressure enhancements - jets - are regularly observed downstream of the Earth’s bow shock. They drive enhanced particle acceleration, larger amplitude magnetic field variations and reconnecting current sheets. Various shock simulations have also exhibited jets, suggesting that they are not unique to Earth.In this study, we search for similar dynamic pressure pulses downstream of interplanetary shocks observed by the Wind spacecraft. We discuss how the jet selection criteria are adapted for such conditions. The interplanetary shocks where we have found jet candidates feature foreshock activity, a favourable condition for jet formation according to bow shock studies. We examine the properties of the candidate jets and compare them to those reported for magnetosheath jets. Widening the range of environments where downstream jets are observed can shed light on their dynamics and formation mechanisms.
A public-facing landslide early warning dashboard with sparse inventory data and community input: experience from Sitka, Alaska, USA
Authors: Luna Lisa , Patton Annette , Roering Josh , Jacobs Aaron , Korup Oliver , Mirus Ben
Published: February 2023

Following a fatal debris flow in 2015, community leaders and technical experts in Sitka, Alaska determined the need for a landslide early warning system. Here, we present the development of a public-facing landslide early warning dashboard that relies on statistical models that incorporate only five reported landslide events and station-based precipitation data between 2002 and 2020. We evaluated strategies for training landslide forecasting models with a limited record of landslide-triggering rainfall events, which is a common limitation in remote, sparsely populated regions. We estimated the daily probability and intensity of potential landslide occurrence with logistic and Poisson regression, respectively, employing both frequentist and Bayesian inference. We compared a series of models trained on cumulative precipitation at timescales ranging from one hour to two weeks using Akaike, Bayesian, and Leave-One-Out information criteria. We found that, in Sitka, three-hour precipitation totals were the best predictor of elevated landslide hazard and adding antecedent precipitation (over days to weeks) did not improve model performance, likely reflecting the rapid draining of porous colluvial soils on steep hillslopes. We then evaluated the best-fit three-hour precipitation models using leave-one-out cross validation as well as by testing a subset of the data. We found that probabilistic models trained with few landslide-triggering and many non-landslide-triggering events could effectively distinguish days with landslides from days without. We used the resulting estimates of daily landslide probability to establish two decision boundaries for three levels of warning. Considering community input, we set the lower boundary such that no missed alarms would have occurred between 2002 and 2020, and the upper boundary such that no false alarms would have occurred. With these decision boundaries, the logistic regression model incorporates National Weather Service quantitative precipitation forecasts into a real-time landslide early warning dashboard system (sitkalandslide.org). This dashboard provides accessible and data-driven situational awareness for community members and emergency managers.
Observations of tidal attenuation and amplification in a mangrove forest: channels as conduits
Authors: Pelckmans Ignace , Vermeulen Ben , Alex Ramos-Veliz John , Mishell Rosado-Moncayo Andrea , E. Dominguez-Granda Luis , Belliard Jean-Philippe , Gourgue Olivier , Temmerman Stijn
Published: February 2023

Mangroves are increasingly recognized as an effective nature-based coastal defence strategy. Mangrove trees are proven to reduce the height of propagating long-period waves such as storm tides and extreme sea levels. Existing empirical studies, however, are limited to small scales (~10²-10³ m) or only cover continuous belts of mangroves. Here we present water level measurements along a 20 km channel and in the surrounding mangrove forests for regular neap- and spring tides in a natural mangrove forest in the Guayas Delta, Ecuador. For tides with peak water levels which are high enough to flood the surrounding mangroves, inundation levels reached 45 cm with attenuation rates up to 40 cm/km. Along the entire 20 km channel, however, no attenuation occurred. Instead, we measured amplification with rates varying between 4.3 and 4.6 cm/km. Amplification rates increased with peak water level until water levels were high enough to flood the surrounding mangroves, upon which amplification rates decreased with peak water level. The latter implies that with higher peak levels, such as during an extreme sea level event, the capacity of mangroves to dampen amplification or even attenuate increases.
What is the real impact of instabilities and ageing infrastructure along roads and railways ? Analysis of an event inventory in the Western Alps, Switzerland
Authors: Gutierrez Amalia , Derron Marc-Henri , Fei Li , Gerber Christian , Jaboyedoff Michel
Published: February 2023

The effects of climate change on ageing infrastructures, due to temperature variations, insolation, and especially increased runoff due to extreme precipitations, are not insignificant. In addition,  expected changes in land use and increased impact of anthropic activity, as well as  the degradation of infrastructures due to age, will potentially impact the utility lifespan of a great variety of works. Whether it be retention walls for vineyards, near roads or next to railroad tracks, it is important to determine to what extent climate change and anthropic activity will accentuate the hazard of failure of protective or retaining infrastructures and their backfills. Especially when these are located along busy routes (pedestrian, automobile, railroad, etc.) and can potentially impact moving objects (for example trains with passengers). Even though these events are not so rare, and  the damages caused are easily repaired or managed, their global costs and impacts are very seldom quantified. In order to gain a better overview on the global cost of these types of events and the associated impacts, in particular in areas where maintenance is not so frequent, an inventory of events for the Western Alpine Switzerland was carried out. The associated costs were ascertained either in prevention and maintenance work or in emergency measures and reparation. Examples of events having a significant impact, include those of La Conversion (2021), Châtillens Ecublens-Rue (2013), Col de la Croix (2021), L’Etivaz (2018), La Forclaz (2018, 2022), Col des Mosses (2015), route d'Oron (2014, 2021), Ollon (2021), and Belmont-sur-Lausanne (2021); which were studied in more detail. Information on these events were gathered from various sources including newspaper articles, official reports, and interviews with witnesses and experts. And the conditions leading to such events, such as antecedent precipitation, age of the structure and structural condition, were investigated and analyzed. The results of the analysis were then used to identify a few sites susceptible to this kind rupture in the future, via reports, aerial images, and fieldwork, and subsequently mapped and communicated to the corresponding authorities.
See Seagrass from Space: From Analysis-Ready PlanetScope Satellite Imagery to Nationwide Seagrass Maps for the Nationally Determined Contributions of Seychelles
Authors: Lee Chengfa Benjamin , Martin Lucy , Traganos Dimosthenis , Rowlands Gwilym , Reinartz Peter
Published: February 2023

Seagrass meadows provide many valuable global ecosystem services including blue carbon sequestration, and habitat and nursery ground provisioning for commercial fish. Yet, the conservation, research and monitoring of these highly productive habitats are hampered by a notable lack of spatially-explicit knowledge in many parts of the world, including the Seychelles. As an archipelagic state, a sizeable portion of the Seychellois Nationally Determined Contributions and thus carbon stocks are “blue”, owing to the therein intertidal and subtidal seagrasses.Due to the subtidal seagrass living on the seabed, the dominant spaceborne remote sensing approach is optical. However, owing to the atmospheric conditions and persistent cloud cover over tropical regions, it is sometimes difficult to find a suitable, cloud-free and glint-free image. In order to maximise use of every relevant and useful pixel without discarding them due to a partial cloud cover, we employ a multitemporal image composition approach, which concurrently reduces some of the effects of sunglint and cloud shadows. However, a multitemporal approach on a national scale is computationally expensive and requires much resources.Here we present the Global Seagrass Watch coastal Ecosystem Accounting framework, which harnesses the powerful cloud computing Google Earth Engine (GEE) platform to process the satellite images across a large spatial and temporal scale. Furthermore, with the addition of the Planet & Norway’s International Climate and Forests Initiative (NICFI) onto GEE, anyone can have free access to the 4.77 m high spatial resolution PlanetScope image composites between 2015 to present. Although terrestrially-focused, the presence of shallow waters within the buffered coastline in these composites allows the exploitation of NICFI for coastal aquatic remote sensing, as well. Consequently, a potentially high-resolution, large-scale seagrass map could be produced with savings in time and cost.In this study, we implement our multitemporal composition approach on GEE onto the PlanetScope composite archive in order to map and estimate the area of the seagrass meadows of Seychelles on a national level.The results will contribute to the development of a national seagrass mapping and monitoring blueprint monitoring system, which is important for the assessment of national seagrass blue carbon stocks for the Nationally Determined Contributions for Seychelles, as well as beyond.
Developed a climate modeling framework for India
Authors: Bhuyan Debi Prasad , Mishra Saroj Kanta
Published: February 2023

A better representation of the poorly understood sub-grid scale processes in the Global Circulation Model is imperative for the skilful simulation of the Indian Summer Monsoon (ISM). We customized the parametrizations for deep convection, gravity wave, and surface layer; incorporated them into the NCAR Community Atmosphere Model 5.0 (NCAR CAM5, base model). The modified deep convective parametrization includes dynamic tau (dynamic convective adjustment timescale), which allows a spatiotemporally varying tau instead of constant tau and the stochastic entrainment rate in place of a fixed entrainment rate. Similarly, the modified gravity wave parametrization facilitates estimating the response of upper-level gravity wave drag induced from secondary sources. Likewise, the modified surface layer parametrization enables a better representation of near-surface variables as well as surface fluxes. The simulations of default and customized NCAR CAM5 have been carried out for eleven years (one year for spin-up and the rest ten years considered for analysis). The analysis has been performed for two major climate change indicators, i.e., temperature and precipitation for the ISM season (June to September). The model simulated near-surface temperature and precipitation during ISM were evaluated against observation (Indian Meteorological Department). A significant improvement has been noted in simulating the total precipitation pattern and magnitude over India, as well as for surface air temperature, particularly over northern India. In addition, based on performance, the customized model alleviates some of the long-standing biases evident in the default NCAR CAM5 simulation over India. Furthermore, compared to the base model, the customized model realistically simulates the annual cycle of precipitation, medium and extreme precipitation rates, meridional tropospheric temperature gradient, upper (200 hPa) and lower (850 hPa) tropospheric winds, Madden Julian Oscillation, and equatorial waves. The study’s findings illustrate the significance of model parametrizations towards improving the ISM simulation. Meanwhile, the modeling framework would be essential for credible future climate projections of India and would become a vital tool for policymakers and diverse stakeholders.Keywords: Indian Summer Monsoon, NCAR CAM5, Deep convection, Gravity wave, Surface layer
FORESTER – Interactive visualization of tree-based machine learning
Authors: Strahl David , Reinecke Robert , Wagener Thorsten
Published: February 2023

Visualizations are crucial for machine learning as they allow practitioners to understand, analyze, and communicate their models. They help interpret complex models by providing a graphical representation of both data and model performance. Visualizations can be used to understand the underlying patterns and trends in the data, identify biases and errors, and diagnose problems with the model. They also help in communicating the results of the model to a non-technical audience by providing an intuitive and interactive way to present the findings.Tree-based machine learning methods, such as Classification and Regression Trees or Random Forest, are well-established and widely used in the Earth Sciences. However, visualization tools provided by common machine-learning environments in Python, R, or Matlab often provide graphical representations that could be more visually appealing or helpful in conveying a clear message.Here we present FORESTER, a web-based and open-source software that produces visually appealing tree-based visualizations. Forester produces publication-ready plots that are, at the same time, interactive figures that can guide the user in interpreting the model. Visualizations can be streamlined to the user's requirements and offer a wide variety of insightful techniques. This makes Forester a promising alternative to currently used environments. Forester is open to collaborations, so we hope it will be extended within the Earth Science community and beyond, proving useful in other machine-learning-related fields.
Trends in plant species-wise abundances with parallel maintenance of community-level diversity in a Hungarian sandy pasture
Authors: Fóti Szilvia , Balogh János , Bartha Sándor , Pintér Krisztina , Nagy Zoltán
Published: February 2023

The relative importance or the abundance of plant species in ecosystems shows large spatio-temporal variability due to habitat- and species-related factors. What is more, in Hungary, climate change is accompanied by an increased probability of droughts and heat waves with further consequences on community attributes both in time and space.The finely undulating (no more than 1.5 m elevation differences within the study site) surface in our sandy grassland study site was formed through the combined effects of wind, water erosion, and drought, and resulted in uneven soil nutrient and water distributions. We surveyed the vegetation of an ~ 1 ha area along 15 campaigns covering spring, summer, and autumn aspects for 7 years in 80 × 60 m grids where the surface cover of plant species within 78 patches of 0.5 × 0.5 m quadrates was recorded. The large spatial and temporal dataset (n=78 × 15=1170 quadrates with an overall species number of 114) enabled us to follow both species-wise (abundances) and community-level (e.g., diversity) patterns along with different terrain attributes for years.During the study period, the grassland functioned as a carbon sink with a balanced physiological performance with year-to-year variability. The yearly sum of precipitation was very variable without any statistically significant change since the establishment of the study station (2002); however, significant warming was observable since then.Within the study area, vegetation differentiation was detectable along with the terrain attributes. This vegetation differentiation was temporally variable following the patterns of how species with different environmental requirements split available places/resources through time. At hotter, dryer, more elevated positions, and more on the ridges, we could differentiate a larger ratio and diversity of a group of species favoring such conditions, while another group was more abundant in areas with opposite conditions. The presence of such different species groups and functional types within this relatively small area with a slight surface undulation may have been responsible for the observed balanced physiological performance of the grassland. However, although the diversity of the community as a whole didn’t change significantly during the study period, one of the ecological group diversities, that of species favoring cooler, wetter positions, decreased. So, not only temporal variability but also trend-like shifts were observable in the vegetation composition through time, and the stability of the diversity was found to show a terrain-related pattern.