bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity of numerical simulations in an idealized valley to surface parameters
Authors: Di Santo Dario , Zonato Andrea , Giovannini Lorenzo
Published: March 2022

Land surface models (LSMs), i.e. parameterization schemes for evaluating surface-atmosphere exchange implemented in meteorological models, usually prove inadequate over complex terrain,where orography strongly influences atmospheric processes and their interaction with the surface. In particular, LSMs use several parameters to suitably describe the surface and its interaction with the atmosphere, whose determination is often affected by many uncertainties. To this date, the sensitivity of meteorological model results to these parameters has not yet been studied systematically in complex terrain.The purpose of this work, which lies in the context of the TEAMx-related project ASTER, funded by the EGTC European Region Tyrol-South Tyrol-Trentino, is to evaluate the sensitivity of simulations with the Weather Research and Forecasting (WRF) meteorological model to variation of parameters describing land cover. Specifically, an idealized three-dimensional topography consisting of a valley-plain system is adopted and the analysis of the results focuses on the development of thermally-driven circulations. The analysis considers both the sensitivity to the type of vegetation cover and to the systematic variation of surface parameters based on typical values found in the literature. In particular, this analysis is carried out using the Global Sensitivity Analysis (GSA) methodology in order to quantify the uncertainty associated with the variation of each parameter evaluated and to estimate the optimal computational effort required for this type of study. The outcome of this analysis allows to evaluate which are the parameters that most influence model results and therefore should be estimated with particular attention in order to obtain reliable simulations over complex terrain.
Deforestation and climate change: The multiple pressures over Amazonian forests
Authors: Artaxo Paulo , Toledo Machado Luiz Augusto , Menezes Franco Marco Aurélio , Barbosa de Albuquerque Itiara Mayra , Rizzo Luciana Varanda , Shimbo Julia , Alencar Ane , Trumbore Susan , Silva José Reinaldo
Published: March 2022

Amazonia is under significant stress from both deforestation and climate change. Multiple pieces of evidence show that the links between the hydrological and carbon cycles are fast changing. Deforestation is increasing in Amazonia, and in 2021, about 13,35 km² of forests were converted, a value 22% larger than 2020. On the deforestation side, the government's recent public policies favor illegal occupation of public lands and invasion of indigenous territories protected by the Brazilian constitution. Deforestation brings forest degradation to the edges of deforested areas, increasing carbon emissions. The impact of climate change is less clear, with changes in the hydrological cycle and increased temperature, promoting forest degradation that makes parts of the Amazon Forest become a carbon source.

The Amazonian forest is a very complex system with multiple anthropogenic and climate change pressures. It is hard to know where a possible Amazonian tipping point could be and which variables or values could be the indicators for this possible tipping point. The role of intensified climate extremes is another critical variable, with Amazonia under increased intense droughts/inundation cycles in the last 30 years. Remote sensing measurements show that vapor pressure deficit is increasing for both perturbed Eastern and at the pristine Northern Amazonia. Several different studies show that the carbon uptake by undisturbed forests is not equilibrating the carbon emissions by deforestation for parts of Amazonia. CO2 emissions associated with deforestation are increasing. The MapBiomas system provides detailed land-use change maps linked to meteorological information to apportion carbon emissions to forest degradation or deforestation. The role of soil emissions is not fully quantified for the overall Amazonia. We are developing a basin-wide system using big data strategies with machine learning, artificial intelligence, and other advanced techniques to address drivers for land-use changes in Amazonia and carbon and methane emissions and sinks. Flooded areas in Amazonia show significant methane emissions, and the effects of increasing floods and droughts cycles have an important impact on methane emissions. First results will be presented, with CO2 and CH4 ground-based and remote sensing measurements in Amazonia, coupled with MapBiomas land-use change maps.
Emergence of large-scale hydrodynamic structures due to atmospheric offshore wind farm wakes
Authors: Christiansen Nils , Daewel Ute , Djath Bughsin , Schrum Corinna
Published: March 2022

The aerodynamic drag of wind turbine rotors creates downstream wake structures in the atmosphere, which represent decreasing wind speed and increasing turbulence behind wind turbines. In the marine environment, these atmospheric wakes entail attenuated wind forcing at the sea surface boundary and thus imply consequences for wind-driven processes in the ocean dynamics. Based on the unstructured-grid model SCHISM, this study presents a new cross-scale hydrodynamic model setup for the southern North Sea, which enables to simulate wake effects in the marine environment at high resolution. We introduce an observational-based empirical approach to parameterize the atmospheric wakes in the hydrodynamic model and simulate the seasonal cycle of the summer stratification in consideration of the current state of European offshore wind farm development. The simulations show the emergence of large-scale structural changes in local hydro- and thermodynamics due to the wind speed reductions caused by offshore wind farms. The wake effects lead to spatial variability of the mean horizontal currents and, in particular, affect the stratification strength during the summer season. Our results aim to advance understanding of how coastal systems adapt to anthropogenic stressors such as offshore wind farms and raise awareness of potential changes to the future ocean. In particular, large-scale changes in stratification suggest potential consequences for biogeochemical processes and marine ecosystem dynamics.
Efficacy of pedogenetic horizons sampling for site-specific assessment of soil organic matter
Authors: De Feudis Mauro , Falsone Gloria , Vianello Gilmo , Agnelli Alberto , Vittori Antisari Livia
Published: March 2022

The role of soil organic carbon (SOC) in avoidance, mitigation and control land degradation in forest ecosystems is largely recognized. For these reasons, a satisfactory SOC monitoring aimed to drive sustainable SOC management is necessary to avoid soil forest degradation. In this work we thus aimed to a) compare the soil organic carbon stock (OC stock) obtained by pedogentic horizons (PED) and fixed depth layer (FIX) in different forest ecosystems; b) discuss the differences in SOC data provided by the two soil sampling approaches, clarifying their major advantages and drawbacks; and c) to assess the ability of PED and FIX sampling approaches to keep information about horizontal and vertical SOC distribution. On the Apennine chain (North Italy), uneven–aged sweet chestnut, European beech and Norway spruce forests were selected. In each site, a representative area (18 m × 18 m) has been selected and, in the centre of the area, a soil profile has been investigated. Further, within the representative areas 8 additional sampling points were identified. Both for soil profiles and the additional sampling points, soil collection was performed both by PED and FIX (0–15 and 15–30 cm). For each forest stand, no difference of OC stock in 0–30 cm soil depth was found between PED and FIX sampling approaches, however SOC distribution along 0-30 cm provided by PED sampling was more informative on SOC dynamics. The findings obtained through the sampling by FIX would indicate a positive effect of conifers on SOC storage, the PED sampling allowed to assess that SOC under spruce forest was greatly stored in the organic horizons (Oe and Oa) because of the recalcitrant nature of the spruce litter, that does not allow the organic carbon stabilization through the association with mineral particles. Therefore, the spruce forest soil would not lead structural stability and resilience to soil degradation. Sampling by PED also preserved the information about the spatial variability within each study site. In fact, we noted higher coefficient of variation when soil horizons were considered compared to FIX (from 19.2 to 72.8% and from 16.5 to 25.7%, respectively). Overall, in a view of SOC monitoring, our findings demonstrated that the sampling by PED draws a better picture of SOC distribution along depth and its potential susceptibility to external factors leading to degradation. Further, the loss of information about SOC stabilization process and spatial variability would indicate the inability of FIX sampling to support decision–making plans addressed for sustainable use of soil resource.
Palaeofire: current status and future opportunities
Authors: Harrison Sandy , Gallagher Daniel , Lincoln Paul , Liu Mengmeng , Shen Yicheng , Sweeney Luke , Villegas-Diaz Roberto
Published: March 2022

Sedimentary charcoal records are widely used to reconstruct regional changes in fire regimes through time in the geological past. The Reading Palaeofire Database (RPD) represents the most comprehensive compilation of sedimentary charcoal data currently available. It contains 1673 individual charcoal records from 1480 sites worldwide, with sufficient metadata to allow for the appropriate selection of sites to address specific questions. Most of the records have new age models, made by re-calibrating the radiocarbon ages using INTCAL2020 and Bayesian age-modelling software. In this talk we will show how these data are being used to document changing fire regimes during the Late Quaternary and to explore how fire regimes have responded to changes in climate, vegetation and human activities. We will demonstrate the progress that has been made to calibrate the charcoal records and make quantitative estimates of fire properties. We will also explore how these data can be used to evaluate and benchmark process-based fire-enabled models. Finally, we will highlight opportunities to use the palaeo-record together with models to explore fire regimes and their consequences for land-surface processes, biogeochemical cycles and climate.
A fast, single-iteration ensemble Kalman smoother for sequential data assimilation
Authors: Grudzien Colin , Bocquet Marc
Published: March 2022

Ensemble-variational methods form the basis of the state-of-the-art for nonlinear, scalable data assimilation, yet current designs may not be cost-effective for reducing prediction error in online, short-range forecast systems. We propose a novel, outer-loop optimization of the Bayesian maximum a posteriori formalism for ensemble-variational smoothing in applications for which the forecast error dynamics are weakly nonlinear, such as synoptic meteorology. In addition to providing a rigorous mathematical derivation our technique, we systematically develop and inter-compare a variety of ensemble-variational schemes in the Lorenz-96 model using the open-source Julia package DataAssimilationBenchmarks.jl. This high-performance numerical framework, supporting our mathematical results, produces extensive benchmarks that demonstrate the significant performance advantages of our proposed technique versus several similar estimator designs. In particular, our single-iteration ensemble Kalman smoother (SIEnKS) is shown both to improve prediction / posterior accuracy and to simultaneously reduce the leading order cost of iterative, sequential smoothers in a variety of relevant test cases for operational short-range forecasts.  These results are currently in open review in Geoscientific Model Development (Preprint gmd-2021-306) and the Journal of Open Source Software (Preprint #3976).
Glacial Ocean Carbon and Oxygen Cycles: Biological Pump or Disequilibrium?
Authors: Schmittner Andreas , Khatiwala Samar , Cliff Ellen
Published: March 2022

Increased ocean carbon storage and reductions in deep ocean oxygen content during the cold phases of the Pleistocene ice age cycles have been mostly attributed to a stronger biological pump. However, recent studies have emphasized that changes in air-sea disequilibrium played a major role. Here we diagnose a data-constrained model of the ocean during the Last Glacial Maximum to decompose carbon and oxygen cycling into its different components. Individual drivers such as temperature, sea ice, circulation and iron fertilization have been quantified for each component. We show that due to differences in air-sea gas exchange between carbon and oxygen, the components respond differently, which complicates/invalidates interpretations of oxygen changes in terms of carbon. We find changes in disequilibrium dominate both carbon and oxygen changes, whereas the biological pump was not more efficient in terms of global changes for both elements. However, whereas for carbon both the physical and the biological disequilibrium play important roles, for oxygen the biological disequilibrium is dominant, while the physical disequilibrium is negligible. Moreover, whereas for carbon temperature (amplified by physical disequilibrium) and iron fertilization (amplified by biological disequilibrium) are the dominant drivers, oxygen disequilibrium changes are driven mostly by sea ice, with iron fertilization playing a secondary role.
Climate history dictates microbial metabolic response to drought stress: from semi-arid soils to tropical forest precipitation gradients 
Authors: Bouskill Nicholas , Karaoz Ulas , Chacon Stephany , Khurram Aizah , Dietrich Lee , Holman Hoi-Ying , Cusack Daniela
Published: March 2022

The frequency and intensity of environmental fluctuations play an important role in shaping microbial community composition, trait-distribution, and adaptive capacity. We hypothesize here that a communities’ climate history dictates it’s metabolic response to future perturbation under a changing climate. Such a response is significant as changes in microbial metabolism can, in turn, feedback onto metabolite exudation, the chemical structure of necromass, and the formation and stability of soil organic matter. Here we use laboratory and field experiments to examine the metabolic pathways invoked under osmotic and matric stress within semi-arid and tropical soils. For example, using non-destructive, synchrotron-based Fourier-transform infrared spectromicroscopy we profiled the stress response of phylogenetically similar bacteria isolated from soils with contrasting climate histories subjected to both matric and osmotic stress. We note a strong carbohydrate-based, metabolic response of tropical microbes that is entirely absent in semi-arid organisms. At the field scale, we use metagenomic sequencing and metabolite analysis to demonstrate how four different sites established across a 1 m precipitation gradient from the Caribbean coast to the interior of Panama respond to a 50 % reduction in throughfall. The precipitation gradient permits the development of distinct communities at each site that show clearly divergent response to imposed hydrological perturbation. Our contribution here will discuss how communities adapted to different precipitation regimes respond metabolically to drought conditions, and how these change feedback onto the structure and stability of soil organic matter.    
Use of electromagnetic tools to evaluate the risk of silting of the ‘Sélune’ river bed following the dismantling of the 'Vezins' and 'Roche Qui Boit' dams.
Authors: Mouhamadoul Moustapha BA
Published: March 2022

The hyporheic zone is a thin porous sedimentary interface that connects the river to the water table. It is a place where a large part of the groundwater transits and mixes with surface water. Recent studies point to the key role of this zone, a natural biological reactor at the groundwater-river interface, in altering the nitrogen and carbon cycles, capturing and releasing contaminants and buffering river temperatures. Past studies have suggested that, locally hyporheic fluxes can overtake groundwater-river exchanges, although the physical conditions (permeability, roughness, head, ...) under which such scenario occurs remains unclear. In this study, geophysical monitoring of electromagnetic conductivity along a river reach (Sélune, France) was used to identify longitudinal variations in bed permeability, and identify potential hotspot of hyporheic exchanges.
In practice, we will measure electrical conductivity at different depths into the river sediment using the electromagnetic instrument “CMD explorer”. The instrument is displaced over the river surface using a floating board. A two-layer model is then considered to separate the contribution of sediment bed and water column conductivities. Based on the law (Archie, 1942) in a saturated environment, we link measured variations in electrical conductivity to variations in sediment properties such as pore volume change. In parallel, manual permeability measurements of the riverbed were performed to compare and validate the permeability deduced by the electromagnetic method.
The recent removal of two dams over the Sélune river which was associated with an abrupt change of transported sediment load motivates us to perform time-lapse measurements of electromagnetic conductivity in several sectors upstream and downstream of the dams, before and after removal. Such repeated measure provides interesting data on the time scales of bed clogging processes and its impact on hyporheic exchanges.
SUHMO: an AMR SUbglacial Hydrology MOdel 
Authors: Felden Anne , Martin Daniel , Ng Esmond
Published: March 2022

Water flowing under ice sheets and glaciers can have a strong influence on ice dynamics, particularly through pressure changes, suggesting that a comprehensive ice-sheet model should include the effect of basal hydrology. Modeling subglacial hydrology remains a challenge however, mainly due to the range of spatial and temporal scales involved - from subglacial channels to vast subglacial lakes. Additionally, subglacial drainage networks dynamically evolve over time. To address some of these challenges, we have developed an Adaptive Mesh Refinement (AMR) model based on the Chombo software framework. We extend the model proposed by Sommers and others, (2018) with a few changes to accommodate the transition from unresolved to resolved elements. We handle the strong non-linearities present in the equations by resorting to an efficient non-linear Full Approximation Scheme (FAS-MG) algorithm.  We outline the details of the algorithm and present convergence analysis results demonstrating its effectiveness. Additionally, we present results validating our approach, using test cases from the SHMIP inter-comparison project (2018). We finish by discussing ongoing work related to the coupling of SUHMO with the BISICLES AMR ice-sheet model.
Global, hemispheric, and regional temperature anomalies - how different are they and what does it mean?
Authors: Gronwald Marc
Published: March 2022

This paper analyses time series properties of global, hemispheric, and regional temperature anomalies. Using methods such as structural break tests, fractional integration models as well as a test for (temporary) explosiveness, the paper analyses how different they are and what it means. The paper finds that, first, that there is considerable heterogeneity in both timing and number of structural breaks across regions and levels of aggregation. Second, there is evidence of fractional integration in regional time series the extent of which, in addition, differs across regions. Third, evidence of (temporary) explosiveness is found in global and hemispheric temperature anomalies. These findings overall suggest that the properties of temperature series are more complex than originally thought. This is of relevance for analyses of the relationship between temperatures and radiative forcing from greenhouse gases; a key question in climate change research. The conventional view is that this relationship is linear. Finally, as explosiveness is commonly found in financial and commodity markets data during extreme price episodes, the finding of explosiveness in temperatures illustrates the extent temperature changes have already reached.
Spatial pattern and influencing factors of Slope Length and Steepness Factors (LS) in Qinghai Xizang Plateau
Authors: Li Endan , Yang Qinke , Pang Guowei , Wang Chunmei , Yang Lijuan , Qiao Bingjie
Published: March 2022

Topography is the result of geological tectonic movement and land erosion development, which is min factor for slope processes such as surface runoff and soil erosion. At present, there is insufficient research on the spatial pattern and influencing factors of Slope Length and Steepness (LS) factors in the Qinghai-Tibet Plateau (QTP). Based on the 30m resolution SRTM (Shuttle Radar Topography Mission) digital elevation data, we calculates the Hack profile and area-elevation integral parameters, extracts the slope, slope length and LS factor, and analyze their relationship with the elevation. The results show that: 1) the slope and LS factor are small in the centre area of the plateau, and LS decreases from southeastern to the northwestern. The terrain inside the plateau is flat, surrounded by high mountains, and the slope, slope length and LS value are large in areas with large topographic relief; 2) The Hack profiles of the six main rivers including , etc, in the QTP are convex, and the hypsometric curve  of the rivers is close to convex. The geomorphic evolution of the region is in its youth stage as a whole, indicating that the neotectonics of the Qinghai-Tibet Plateau is active. This geomorphic feature makes the LS value distributed in Hengduan Mountains, Western Sichuan Plateau, Yarlung Zangbo River Grand Canyon, etc; 3) The overall dominent of LS in the QTP is slope steepness, while in the steep areas on the edge of the plateau is slope length, and the gentle areas centre QTP is slope; 4) The distribution characteristics of LS are consistent with soil erosion types. The extremely steep slope areas are mainly affected by glacier erosion, while the steep slope areas such as Southeast Tibet are greatly affected by water erosion, The transition zone between the plateau surface and marginal mountains is mainly water erosion and freeze-thaw erosion, and in the dry Qiangtang plareau has strong wind erosion The geomorphic and erosive topographic characteristics of the QTP discussed in the paper, will be a theorical base for the extraction of topographic factors in soil erosion and hydrology, and also has implications for research of multispherical interactions in Tibetan Plateau's earth system.
On the possible magnetospheric and ionospheric sources of the geoelectric field variations during the May 2021 Geomagnetic storm.
Authors: Piersanti Mirko , D'Angelo Giulia , Recchiuti Dario
Published: March 2022

The space environment near Earth is constantly subjected to changes in the solar wind flow generated at the Sun. Examples of this variability are the occurrence of powerful solar disturbances, such as coronal mass ejections (CMEs). The impact of CMEs on the Earth's magnetosphere perturbs the geomagnetic field causing the occurrence of geomagnetic storms. Such extremely variable geomagnetic fields trigger geomagnetic effects measurable not only in the geospace but also in the ionosphere, upper atmosphere, and on the ground. For example, during extreme events, rapidly changing geomagnetic fields generate intense geomagnetically induced currents (GICs). In recent years, GIC impact on the power networks at middle and low latitudes has attracted attention due to the expansion of large-scale power networks into these regions. This work presents the analysis of the geoelectric field determined by the use of the MA.I.GIC. (Magnetosphere - Ionosphere - Ground Induced Current) model, on May 12, 2021 Geomagnetic Storm over the northern hemisphere. In addition, we discriminate between the ionospheric and magnetospheric origin contribution on the geoelectric field in Europe and on the Northern America in order to evaluate their relative contribution to the GIC amplitude.
Modeling the Northern eddy-driven jet stream position and wind speed variability with stochastic coupled non-linear lattices
Authors: Noyelle Robin , Faranda Davide , Yiou Pascal
Published: March 2022

On a synoptic time scale, the northern mid-latitudes weather is dominated by the influence of the eddy-driven jet stream and its variability. The usually zonal jet can become mostly meridional during so-called blocking events, increasing the persistence of cyclonic and anticyclonic structures and therefore triggering extremes of temperature or precipitations. During those events, the jet takes unusual latitudinal positions, either northerly or southerly of its mean position. Previous research proposed theoretically derived 1D models of the jet stream to represent the dynamics of such events. Here, we take a data-driven approach using ERA5 reanalysis data over the period 1979-2019 to investigate the variability of the eddy-driven jet latitudinal position and wind speed variability. We show that shifts of the jet latitudinal position occur on a daily time scale and are preceded by a strong decrease of the jet zonal wind speed 2-3 days prior to the shift. We also show that the dynamics of the jet zonal wind speed can be modelled by a non-linear oscillator with stochastic perturbations. We combine those two results to propose a simple 1D model capable of representing the statistics and dynamics of blocking events of the eddy-driven jet stream. The model is based on two stochastic coupled non-linear lattices representing the jet latitudinal position and zonal wind speed. Our model is able to reproduce temporal and spatial characteristics of the jet and we highlight a potential link between the propagation of solitary waves along the jet and the occurrence of blocking events.
Glacier Gifts: adventures in creative writing in the Peruvian Andes
Authors: Clason Caroline , Rangecroft Sally , Grados Bueno Claudia , Dextre Rosa Maria , Hoyos Evelyn , Hurtado Quispe Kelly , Samuels Diane
Published: March 2022

Glacier Gifts is a project designed to bring together scientific researchers in the UK and Peru with author and creative, Diane Samuels, to activate public exploration of current environmental research on the impacts of climate change and glacier retreat in Peru. Through a series of virtual creative writing workshops facilitated by Diane, we have collated and edited a collection of pieces, written by our team of researchers and by Diane, for public dissemination, with an aim of stimulating engagement of diverse audiences beyond the scientific community. During the workshops we practised free-writing and word-collage, inspired by key words, phrases, stories, and images of the environment and culture of the Peruvian Andes, producing raw material which was subsequently crafted to combine individual and collective voices in our book. The collection is also illustrated with personal photographs by team members, and original artwork by Caroline Clason. Glacier Gifts draws upon both lived experience in Peru and scientific engagement with the challenges of glacier change and water security in the Andes, linking to the SIGMA: Peru and Nuestro Rio research projects. Glacier Gifts emotionally, imaginatively, and factually, shares the personal, collective, local, and global impacts of environmental change in this climate-sensitive region of the mountain cryosphere, providing an opportunity for scientific narrative to reach a wider, non-academic audience enveloped within a creative experience.
Distribution and controls on the accumulation of fallout radionuclides in cryoconite across the global cryosphere 
Authors: Clason Caroline ,   Rad-Ice team
Published: March 2022

Fallout radionuclides (FRNs) are a product of nuclear accidents and weapons testing, and are known environmental contaminants. There has been extensive research into the risks and consequences of FRN deposition for human and ecosystem health, however this has rarely extended to the cryosphere. The results of our international collaboration reveal widespread accumulation of FRNs in cryoconite spanning 30 glacier sites and 477 samples across the Arctic, the Alps, the Caucasus, North America, the Andes, the Himalaya and Antarctica. The activity levels of FRNs found in many samples are orders of magnitude higher than those found in other environmental matrices such as mosses and lichens, and include some of the highest ever recorded outside of nuclear exclusion zones. This raises important questions around the role of glaciers, and specifically cryoconite and its interaction with meltwater, in concentrating - and eventually releasing - FRNs to levels above those historically deposited in the surrounding environment. We compare FRNs in cryoconite with a range of geographical and environmental factors, and find no significant correlation between 137Cs and distance from Chernobyl, and moderate correlations for 241Am and 210Pb which deteriorate to no significant correlation when only Northern Hemisphere sites are considered. We also find no correlation with distance from the sea, or with mean elevation, but a moderate correlation between precipitation and both 137Cs and 241Am, highlighting the importance of scavenging of atmospheric contaminants by snow. Notably, we find a strong correlation between organic matter and activities of both 137Cs and 210Pb, reflecting the capacity of cryoconite to bind FRNs due the presence of extracellular polymeric substances. This research has, for the first time, shed light on the widespread occurrence of FRNs in glacier catchments across the global cryosphere. The potential risks of FRN exposure for water and environmental quality, including uptake of FRNs by flora and fauna, should be a focus of future interdisciplinary research as glaciers continue to retreat and release legacy contaminants into proglacial environments.
Factors Influencing Diurnal Variation Of Cloud And Precipitation In the Yushu Area, Tibetan Plateau
Authors: Cao Bangjun
Published: March 2022

Using data from cloud radar, ground observations and ERA5 reanalysis data, factors influencing nighttime precipitation during summer in the Yushu area of the Tibetan Plateau (TP) are investigated. The cloud top height (CTH), cloud base height (CBH) and liquid water content (LWC) are compared between the non-precipitating days and precipitating days. The results show that the average CTH during precipitating days over Yushu is below 10 km above ground level (hereafter AGL) in the daytime, while it is more than 10 km AGL at night with the maximum at 23 Beijing Standard Time (BST, = Coordinated Universal Time + 8 hour). The CBH is in phase with the dew-point spread. The precipitation intensity and CTH is in phase with the LWC. The hourly averaged precipitation intensity and convective available potential energy (CAPE) in ERA5 reach the maximum at 21 BST, which is 3 hours ahead of the observations. There is downward motion flow at noon during non-precipitating days, while there is upward motion flow at night during the precipitating days. In addition, the horizontal wind direction in the lower level (below 5000 m) shows clockwise rotation from morning to night. Wind shear occurs in the middle level of the atmosphere, is accompanied by subtropical westerly jet in the upper level. The difference of horizontal wind speed between the level of 200 hPa and 500 hPa is positively related to the LWC, making contribution to the formation of upper-level clouds
First insight into the spatial pattern of macroplastic storage in a mountain river
Authors: Liro Maciej , Mikuś Paweł , Wyżga Bartłomiej
Published: March 2022

Amounts of macroplastic debris stored on different elements of mountain rivers are unknown, but such data are crucial to plan future mitigation activities in these fragile ecosystems. We determined the amounts of macroplastic stored on different surface types (geomorphic units and wood jams) in two reaches of the Dunajec River in the Polish Carpathians. A wide, multi-thread reach stored 36 times more macroplastic per 1 km of river length than the upstream-located narrow, channelized reach (1495.4 kg vs. 41.8 kg). In the multi-thread reach, 43.8% and 41.1% of macroplastic was stored on wooded islands and wood jams that covered, respectively, 16.7% and 1.5% of the area of active river zone. The median of macroplastic mass stored on wood jams equalled 113.2 g/m2 and was 180 times higher than on exposed river sediments, 129 times higher than in the areas overgrown with herbaceous vegetation and 19 times higher than on wooded islands. The results indicated that multi-thread reaches of mountain rivers supporting extensive wooded islands and numerous wood jams are hot-spots of macroplastic storage, whereas channelized reaches lacking these surface types act as transport reaches for macroplastic debris. Thus, multi-thread reaches of mountain rivers in populated areas can be used as target zones for river cleaning actions and downstream ends of channelized reaches as the location for installation of macroplastic trapping infrastructure.
Observation of a Total Eclipse of the Moon at 183 GHz
Authors: Burgdorf Martin , Liu Niutao , Buehler Stefan A. , Jin Yaqiu
Published: March 2022

The observation of an eclipse of the Moon at millimetre wavelengths makes it possible to investigate the electrical and thermal properties of the lunar surface to a depth of 10 cm without being influenced by deeper layers. Such measurements are usually carried out with radio telescopes on Earth. When microwave instruments on weather satellites use observations of deep space for their calibration, however, the whole lunar disk appears sometimes in their field of view as well. We identified such an event with the Advanced Microwave Sounding Unit-B on NOAA-15 that coincided with a total lunar eclipse. From this unique vantage point in a polar orbit around the Earth we could measure, once per orbit, the lunar radiance at 183 GHz - a frequency, where the atmosphere is not transparent.

We found a maximum temperature drop during the eclipse of 47±9 K at 183 GHz, corresponding to 16.6±2.1% of the flux density of full Moon, and of 17.3±6 K, corresponding to 6.4±2.1% of the flux density of full Moon, for the window channel at 89 GHz. The evolution in time of the global flux agrees well with the predictions from a new radiative transfer model simulating the global brightness temperatures. Our measurements are consistent with results reported in the past, except for two, which we consider erroneous. The temperature changes are similar everywhere on the lunar disc. The good agreement between the observations from a weather satellite and theoretical predictions demonstrates that the Moon is very useful as flux reference and for checking the reliability of climate data records from Earth observation.
Imaging the upper crust with ambient seismic noise in natural and urban environments
Authors: Diaz Jordi , Ventosa Sergi , Schimmel Martin , Ruiz Mario , Carbonell Ramon
Published: March 2022

The SANIMS project is focused on the development and application of methods based on seismic ambient noise to image and monitor natural and human-altered environments focusing on two test sites; the Cerdanya Basin in the eastern Pyrenees, and the city of Barcelona. Broad-band and short-period seismometers and a high-density node network have been used to acquire new data.

Broad-band data has been processed using the frequency-dependent phase cross-correlation and time-scale phase-weighted stacking to extract Rayleigh and Love waves. We have obtained Rayleigh and Love group and phase velocities for periods in the 1.5 – 4 s range, that will be inverted to velocity-depth models. The preliminary results show higher velocities to the North, with a well-defined zone with lower than average velocities around the Cerdanya Basin. The geometry of the basin basement has also been investigated using the amplitudes of ambient noise, HVSR methods and RFs, obtaining consistent results. The recently acquired high-density data has already been processed in terms of amplitude variations and will be integrated with the tomographic images.

The data acquired in Barcelona has first been used to monitor human activity during the COVID19 pandemic. Amplitude variations of seismic noise allow to delineate the main geological units of the Barcelona area. HVSR measures using the new data expand the already available results, hence improving the existing seismic hazard maps, and will allow analyzing eventual temporal variations in the measurements. As in the Cerdanya Basin, the data will be used to extract Rayleigh waves and invert for velocities.

Both datasets will also be used to analyze the applicability of the methods based on Rayleigh wave ellipticity inversion of ambient noise and earthquake data to provide S-velocity depth profiles. We expect that the use of ambient noise methods will allow to map the basement and to obtain new higher resolution ambient noise tomographic images of the upper crust in the Cerdanya Basin and to better constrain the subsoil properties of Barcelona. The results in both areas will allow comparing the performance of these methodologies in quiet and noisy areas.

This is a contribution of the SANIMS project (RTI2018-095594-B-I00)
Physicochemical parameters and stable isotope composition of water in Northern Mara Sub-Goldfield, Tanzania: Implications for groundwater-surface water interaction
Authors: Myovela Justine L. , Godfray Godson , Salimu Mohamedi
Published: March 2022

This study focuses on water quality assessment and hydrological aspects around northern Mara Sub-Goldfield (Tanzania). A total of 26 water samples were collected from different sampling sites for physicochemical characterization and H-O isotopes analysis. Parameters such as pH, electrical conductivity (EC), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and total hardness were analyzed for each water sample. The 18O/16O and 2H/1H ratios were measured in water samples and expressed as δ18O and δ2H relative to Vienna Standard Mean Ocean Water (V-SMOW). The study revealed that the majority of drinking water sources meet the recommended World Health Organization (WHO) and Tanzania Bureau of Standards (TBS) levels. Drinking water from Kegonga community borehole (pH=6.62, EC=1690 µs/cm, TDS=1080 mg/l), shallow well east of Ingwe Dam (pH=7.32, EC=1720 µs/cm, TDS= 1000mg/l), shallow well south of tailings dams (pH=7.6, EC=2670 µs/cm, TDS=1780 mg/l) and traditional well (pH=5.76) are not suitable for drinking purposes. Isotopic values of studied water samples have shown a wide variation from -28.5 to 21.4 ‰ for δ2H, -5.37 to 2.37 for δ18O ‰, and -3.7 to 16.08 ‰ for D-excess values. The slope of Local Meteoric Water Line (δ2H = 5. 9 δ18O + 5.51; R2=0.94) is slightly lower than the slope of Global Meteoric Water Line (δ2H = 8.2 δ18O + 11.27; R2=1), which indicates that the majority of studied water samples have been isotopically modified. The study demonstrated that the majority of groundwater has been recharged by more evaporated sources likely wastewater from tailings dams. This finding is supported by the consistency of isotopic signature and physicochemical parameters of several groundwater sources with those of surface water discharged from the mines.

Keywords: groundwater-surface water interaction; water quality; stable isotopes; d-excess; Tanzania
Role of baseline landslide inventory and grid rainfall precision on the sensitivity of susceptibility or hindcast models
Authors: Ozturk Ugur
Published: March 2022

Multivariate logistic regression models are the most popular in estimating landslide susceptibility by assessing various landslide causes—covariates—in mapped landslides or hindcasting landslides by including landslide triggering information such as rainfall. Although the sensitivity of these models to the variety of input data is frequently tested, the influence of data quality on the model accuracy is rarely discussed. For example, accurately representing spatial rainfall variability that triggered landslides may be essential in hindcasting models. Additionally, the properties of the mapped landslides, such as sample size, location, or time, are crucial to set a robust susceptibility model. Using an inventory that predominantly covers larger landslides would hinder a model by broadly covering the diversity of the factors leading to slope instability. Whereas smaller landslides could fail to capture sufficiently the range of values in the covariate space, likely decreasing the model performance. Another aspect is whether the number of mapped landslides is enough to estimate the susceptibility accurately or does more data means a better model. We developed several simple logistic regression models to answer all the above-listed questions relevant to assessing the model sensitivity. The model first demonstrated that global grid rainfall products could not accurately represent spatial rainfall distribution, which has a major influence on a landslide hindcast model. We have further found out that using only part of the individual landslides surprisingly may suffice to make accurate susceptibility estimates. Using smaller landslides in a susceptibility model outperforms a model that relies on larger landslides. Lastly, the model performance marginally varied after progressively adding more landslide data in a pilot study.
Modification and comparison of thermal and hydrological parameterization schemes for different underlying surfaces on the Tibetan Plateau in the warm season
Authors: Yuan Yuan
Published: March 2022

In this paper, three parameterization schemes, one considering gravel influence (test1), one considering organic carbon influence (test2) and one comprehensively considering gravel and organic carbon influence (test3), were set up to modify different typical underlying surfaces of the Tibetan Plateau (TP). In addition, their soil thermal properties and hydraulic property variations were discussed. Additionally, discussing the key thermal and hydraulic parameters affected the performance of different schemes from the perspective of observation data in the TP to improve the simulation ability of soil temperature and soil moisture in the plateau areas. Compared the original Community Land Model (CLM) scheme, test1 resulted in higher soil temperature and lower soil moisture, while test2 had lower soil temperature and higher soil moisture. The key thermal and hydraulic parameters are the changes in the saturated thermal conductivity and the thermal conductivity of dry soil and the variations of the porosity and exponent B, respectively. The test3 scheme was the same as test2 for the modified changes of thermal properties, except that the proportion of change was slightly different. In terms of soil thermal properties, test2 and test3 were better at 0-20 cm depth, while test1 and test3 were better for the deeper (40 cm) simulation. Regarding hydraulic properties, the test1 and test3 schemes performed better on the Gobi and alpine meadows at 20-40 cm depth, while the original CLM scheme and test2 performed better on the underlying grassland surface. Test3 was better at balancing the relationship between the thermal and hydraulic parameters and could be used for the further research on the entire plateau area.
Runoff sensitivity variation should be incorporated in hydrological analysis
Authors: Wang Yaping
Published: March 2022

With great changes, such as climate and land use/cover, occurring in hydrological processes over the last decades, runoff sensitivity, here defined as proportional changes in runoff caused by a given proportional change in its driving factors, has also been changing over time. However, few studies have focused on this sensitivity change, and runoff sensitivity is always considered to be constant in runoff attribution analysis with an elasticity-based method. In this study, we attempt to examine the temporal variation of runoff sensitivity in the middle reaches of the Yellow River basin, China, and quantify its effects on the changes in runoff so that the existing attribution method can be improved. We found that runoff sensitivity showed statistically significant trend, and runoff became more sensitive to changes in climate and catchment characteristics (CC). CC, largely affected by land use/cover change resulting from large scale ecological projects, was the major contributor to change in runoff sensitivity, followed by precipitation, and lastly potential evapotranspiration. Runoff sensitivity variation contributed approximately 20% to the proportional runoff change, and by allowing runoff sensitivity to change over time, relative contributions of climate and CC to runoff would range from − 5.05% to 9.94%. Our study supplements research focusing on hydrological changes and interactions, and we suggest that temporal variation in runoff sensitivity should be considered when quantifying the impacts of driving factors on changes in hydrological processes. 
Molecular and metalic ions in the magnetosphere: ISSI team preliminary results 
Authors: Yamauchi Masatoshi , Dandouras Iannis , Mann Ingrid , Haaland Stein , Würz Peter , Plane John , Kastinen Daniel , Gunnarsdottir Tinna , Yau Andrew , Kistler Lynn , Hamilton Doug , Christon Steve , Saito Yoshufumi , Watanabe Shigeto , Nozawa Satonori
Published: March 2022

Molecular and metallic ions are vastly unexplored in near-Earth space because only a few terrestrial missions have been equipped with dedicated instrumentation to separate these molecular and metallic ions, within only a limited energy range (cold ions of < 50 eV and energetic ions of ~100 keV).  Nevertheless, existing data from past and on-going missions including those not designed for the required mass separation are capable of detecting many of these ions with available tools, although severe limitations exist (sensitivity and energy range in addition to mass resolution and mass range).  By combining these patchy and incomplete data, we found several features that indicate sources of these heavy ions.
(1) Combination of Kaguya and Cluster/RAPID during high flux events of solar wind heavy ions suggests that the Moon can be a substantial source for low charge-state metallic ions in the magnetosphere when the Moon is located upstream of the Earth.  This interpretation is consistent with Geotail/STICS statistics of increased flux of low charge-state heavy ions near new-Moon for medium activity (Kp=2-4).
(2) The major route of molecular ion supply (<10 keV) to the inner magnetosphere can be via low-latitude (< 60° invariant latitude, according to e-POP/IRMS) in addition to the cusp (according to Cluster/CIS and Akebono/SMS) during high outflow flux period.  This indicates extraordinary upward convection (or ion flow) at the sub-auroral region.
(3) A case study of lidar data during high flux events of solar wind heavy ions suggests that upward expansion of Na signal can be associated with molecular ion escape to the magnetosphere that is also observed by Cluster/RAPID and e-POP/IRM, although this expansion can be related to a major magnetic storm rather than solar wind event.