bluuebunny/crossref_metadata_2025 huggingface dataset:
Outgassing efficiency and atmopsheric composition should differ for mobile-lid and stagnant-lid planets
Authors: Noack Lena , Brachmann Caroline
Published: February 2023

The long-term evolution of the atmospheres or rocky planets depends on several different factors, including (but not limited to) volcanic outgassing by partial melting of the rocky interior. Uprising melt may contain different assembladges of volatiles (CHONS) depending on the general mantle composition and redox state, the local volatile inventory, as well as melting depth. All these factors are assumed to vary for mobile-lid planets with an active surface recycling mechanism (e.g. plate tectonics or convective mobile resurfacing) when compared to stagnant-lid planets. In addition, the strength of volcanic activity varies for stagnant-lid and mobile-lid planets, with stronger activity and hence volcanic outgassing expected for the latter case. Atmospheres with pressures above Earth values also severely influence which volatiles will be further outgassed into the atmosphere depending on the solubility of the individual gas species. The outgassing fluxes therefore strongly depend on the evolution of the atmosphere, including atmosphere losses to space or by condensation or weathering. Ultimately, different atmospheric compositions will evolve for planets with low-pressure atmospheres (i.e. low-mass planets, planets without an active surface mobilization process, or planets with efficient atmosphere sinks/losses) and high-pressure atmospheres.Our studies allow us to predict ranges of likely atmospheric properties depending on planet mass and the surface mobility regime, that can then be compared to observations (i.e. with JWST or in the more distant future with the proposed LIFE mission).
Driving processes of long-term large scale groundwater recharge in cold and humid climates
Authors: Emmanuel Dubois , Marie Larocque
Published: February 2023

Large scale and long-term estimates of groundwater recharge (GWR) are strategic for assessing the relative impacts of climate change and land cover (LC) change on groundwater resources. This is especially true in cold and humid climates where global change has a high disrupting potential. Therefore, this work aims to determine the driving processes of long-term and large-scale GWR in cold and humid climates. Using a parsimonious model, GWR was simulated in the cold and humid region of southern Quebec, Canada (35 800 km2) over the past decades (1961-2017) and for potential future conditions (12 scenarios, 1951-2100). Constant and time-variant LC were used, with a monthly time step and a 500 m x 500 m spatial resolution. The datasets and model are open source. The simulated past and future results showed the importance of seasonality for GWR and the key role of annual temperature in the spatial distribution of GWR rates. They highlighted the high responsiveness of the cold and humid region hydrology to long-term interannual climate variability and the importance of simulating the snow and freezing processes when estimating GWR in these climates. In the future, warmer temperatures during the cold months (less precipitation as snow, earlier snowpack melting) led to more liquid water available when the vegetation was dormant, leading to higher GWR. Warmer temperatures during the rest of the year extended the growing period and increased plant water uptake, directly decreasing the water available for GWR. The direction of the annual changes in GWR thus depended on whether the increase during the cold months could offset the decrease during the rest of the year. The sensitivity of GWR to climate change increased with the increase in LC change intensity. The spatial distribution of LC changes was identified as another driver of GWR change as afforestation took place on agricultural areas, located on the flattest and clayey areas, thus reducing the GWR rates for forested area over time. This work called for a more systematic inclusion of LC changes in long-term groundwater resource simulation and proposes a computationally-affordable methodology to tackle it.
Effect of bathymetric data resolution on the understanding of sediment mobility: implications for offshore infrastructure projects on deglaciated continental shelves
Authors: Kurjanski Bartosz , Caruso Simona , McGhee Claire , Rea Brice , Spagnolo Matteo
Published: February 2023

Sediment mobility is one of the key issues considered  during the design and construction process off offshore infrastructure ( Wind farms, cables, pipelines etc.).  Early understanding of the seabed mobility can significantly affect the project timelines, cost and, if not mitigated, can reduce the lifespan of already existing assets.  The most common approach to evaluate sediment mobility relies on repeated bathymetric surveys which aim to unravel the rate of change of the seabed over time. However, repeated surveys to be effective require to be performed over timelines allowing for confident detection of change above the uncertainty threshold and need to consider seasonal conditions within the area of interest. This time separation typically needs to be greater (several years)  the bigger the mobile bedforms across the area.  This means that it is unlikely that a result of a repeated bathymetric survey will be available early in the project life. Here, a public domain repeated bathymetric survey data from a deglaciated continental shelf area offshore N-E Scotland with moderate-to high-resolution(2-8m) data will be used to (1) identify mobile and immobile paleo bedforms, (2)quantify the rate of change of the seabed and (3) investigate the effect on different data resolution on the seabed mobility quantification.
Driving mechanisms of urbanization: Evidence from Geographical, Climatic, Social-economic and Nighttime Light data
Authors: Huang Siyi , Yu Lijun , Cai Danlu , Zhu Jianfeng , Liu Ze , Zhang Zongke , Nie Yueping , Fraedrich Klaus
Published: February 2023

Urbanization induced changes have attracted widespread attention. Key challenges arise from the inherent uncertainties in attribution models diagnosing the driving mechanisms and the interrelationships of the attributes given by the complexity of interactions within a city. Here, we investigate urbanization dynamics from nighttime light signals before analyzing their driving mechanisms from 2014 to 2020 on both provincial and regional scale and a flat versus mountainous urbanization comparison. Model uncertainties are discussed comparing the contribution results from Geodetector and the Gini importance from Random Forest analyses. The method is applied to Shaanxi Province, where flat urban land is located mainly in its center and mountainous urban land is situated in the North and South. The following results are noted: i) Employing the Geodetector based maximum contribution method for urban region extraction of night time light reveals a notable accuracy improvement in flat urban land compared with the closest area method. ii) Geographical factors attain high contribution for mountainous urban land of Shannan, while for flat urbanization land dynamics, economic factors and community factors prevail. iii) The most obvious driving mechanisms are economic factors which, associated with local urban development strategies, show highest contribution values in 2014 (2018) over the flat (mountainous) urban land of Guanzhong Plain (Northern Shaanxi Plateau or Shanbei region) linked with an early (late) development. iv) Population factors achieve high contribution values in the initially low populated urban land of the northern mountainous land initiating huge migration. v) The contributions resulting from Geodetector are in agreement with the Gini importance from Random Forest in agriculture, geographical and population factors (R2 > 0.5) but not in economy, community and climatic factors (R2 < 0.5). The dynamics of driving mechanisms for urbanization provides insights in connecting urban geographical expansion with multi-factors and thus to assist municipal governments and city stakeholders to design a city with geographical, climatic and social-economic changes and interactions in mind.
Cost Efficient Station Monitoring and Remote Data Retrieval for Portable Seismic Stations
Authors: Hamilton Valarie , Pigeon Sylvain , Parker Tim , Perlin Michael , Laporte Michael
Published: February 2023

Remote monitoring as well as remote waveform data retrieval is an enabling capability for portable stations used in seismic hazards studies. Remote monitoring provides intra-deployment visibility of system performance to allow prompt detection, and subsequent resolution, of faults which may otherwise go undetected for the duration of the deployment and jeopardize a seismic campaign's successful outcome.  Waveform data retrieval allows intra-deployment quality control (QC) and can enable faster science. These benefits must be considered against the associated power consumption and telemetry bandwidth costs. These tradeoffs may drive a system implementation that limits remote retrieval to low resolution data or, in other use cases, restricts the retrieval of full resolution waveform data to specific periods of interest only.  In the case of deployments in harsh environments, such as polar or ocean bottom environments where field visits are cost prohibitive or may not be possible, even high cost remote retrieval of a complete data set may be preferable if it offers a savings and / or a reduction in operational risk in comparison to a station visit.
As part of this session, we discuss how advancement in low power portable geoscience instrumentation, combined with low power communication technology, deliver these new capabilities with flexible implementation balancing function and operational cost.
Updated orbital perspective of the Mt. Sharp upper sulfates in preparation for in situ exploration
Authors: Sheppard Rachel , Rapin William , Tu Valerie , Lim Lucy , Gabriel Travis , Hughes Madison , Fraeman Abigail , Vaniman David
Published: February 2023

Mg sulfate (MGS) is one of the most common secondary minerals on Mars, with orbital detections spread across the planet and multiple occurrences and elevations within Gale crater. The mineralogy of MGS (including its crystallinity and hydration state) and its geologic setting can be used to place precise limits on aqueous conditions during formation and diagenesis. Both monohydrated Mg-sulfate and polyhydrated Mg-sulfate have been observed in Gale crater from orbit, and the MSL mission is now within the area where MGS-rich strata are identified from orbit, presenting an opportunity to examine these common martian minerals in situ. We map MGS-rich outcrops along the planned rover traverse route and similar stratigraphic range around all of Mt. Sharp. By comparing CRISM and HiRISE data in a restricted stratigraphic range, we identify small features of interest such as potential thin monohydrated MGS layers. As monohydrated MGS cannot have been exposed to liquid water or frost since formation, these are important outcrops for the rover to conduct contact science and gather high-resolution textural observations which can be used to test formation hypotheses.
Effect of multi-level and multi-scale spectral data source on vineyard state assessment
Authors: Monaco Eugenia , Ezzy Haitham , Brook Anna , Buonanno Maurizio , Albrizio Rossella , Giorio Pasquale , Erbaggio Arturo , Arena Carmen , Petracca Francesca , Cirillo Chiara , De Micco Veronica , Bonfante Antonello
Published: February 2023

Leaf water potential (LWP) is widely used to assess plant water status and it is commonly used by growers to make immediate crop and water management decisions. However, LWP measurement via direct method presents challenges as it is labour, time intensive and represents leaf-level conditions for sampling of small vineyard block. An alternative approach is using pigment concentration as a proxy for the canopy’s water status. Spectral data methods have been applied to monitor and evaluate crops’ biophysical variables. In this study, a model to predict LWP using via UAS equipped with a VIS-NIR multispectral camera and trained machine learning algorithm, is developed and tested.  The model was tested on three dates in 2020 in a commercial vineyard in the Tufo Wine Region. Three modelling approaches (partial least square regression PLSR, support vector machine SVM, artificial neural network ANN) and two input datasets (combining spectral data and spectral vegetation indices) were used to estimate LWP. All approaches predicted LWP-based on spectral data classified from high to low; the results were consistent in direct proportion to the laboratory results and performed the best results. This research shows the potential for estimating LWP at a vineyard scale based on UAS information, represents a good and relatively cheap solution to assess plant status spatial distribution and therefore it could provide a direct way to achieve precise agricultural vineyard.
A 29-year time series of annual 300-metre resolution plant functional type maps for climate models
Authors: Lamarche Celine , Harper Kandice , Hartley Andrew , Peylin Philippe , Ottlé Catherine , Bastrikov Vladislav , San Martín Rodrigo , Bohnenstengel Sylvia , Kirches Grit , Boettcher Martin , Shevchuk Roman , Brockmann Carsten , Arino Olivier , Defourny Pierre
Published: February 2023

The existing CCI Medium Resolution land cover (MRLC) product delineates 22 primary and 15 secondary land cover classes at 300-meter resolution with global coverage and an annual time step extending from 1992 to the present. Previously, translation of the land cover classes into the plant functional types (PFTs) used by the Earth system and land surface models required the use of the CCI global cross-walking table that defines, for each land cover class, an invariant PFT fractional composition for every pixel of the class regardless of geographic location. Here, we present a new time series data product that circumvents the need for a cross-walking table. We use a quantitative, globally consistent method that fuses the 300-meter MRLC product with a suite of existing high-resolution datasets to develop spatially explicit annual maps of PFT fractional composition at 300 meters. The new PFT product exhibits intraclass spatial variability in PFT fractional cover at the 300-meter pixel level and is complementary to the MRLC maps since the derived PFT fractions maintain consistency with the original land cover class legend. This was only possible by ingesting several key 30m resolution global binary maps like the urban, the open water, the tree cover, and the tree height while controlling their compatibility thanks to the MRLC maps. This dataset is a significant step forward towards ready-to-use PFT descriptions for climate modelling at the pixel level. For each of the 29 years, 14 new maps are produced (one for each of 14 PFTs: bare soil, surface water, permanent snow and ice, built, managed grasses, natural grasses, and trees and shrubs each split into broadleaved evergreen, broadleaved deciduous, needleleaved evergreen, and needleleaved deciduous), with data values at 300-meter resolution indicating the percentage cover (0–100%) of the PFT in the given year. Based on land surface model simulations (ORCHIDEE and JULES models), we find significant differences in simulated carbon, water, and energy fluxes in some regions using the new PFT data product relative to the global cross-walking table applied to the MRLC maps. We additionally provide an updated user tool to assist in creating model-ready products to meet individual user needs (e.g., re-mapping, re-projection, PFT conversion, and spatial sub-setting).
Water table dynamics in coastal aquifer sediments alter nitrogen fate: Observations from soil column experiments
Authors: Roumelis Christian , Willert Fabian , Scaccia Maria , Welch Susan , Gabor Rachel , Carrera Jesús , Folch Albert , Salgot Miquel , Insalaco Alycia , Sawyer Audrey
Published: February 2023

Water tables in coastal aquifers respond to a variety of hydrologic forcings, including precipitation, coastal flooding, and tides. The water table response to these forcings has the potential to impact water quality by affecting the fate and transport of nitrogen, particularly in coastal environments where nitrogen can accumulate in soils and water. To investigate the urban and agricultural reactions involving N that occur near the water table, a meter-long column containing reconstructed coastal soil and aquifer layers from a Mediterranean site was made. We continuously monitored in-situ redox potential, soil moisture, and water pressure and collected frequent pore water samples for analysis of dissolved organic carbon (DOC) and dissolved inorganic nitrogen species over 16 days while imposing water table fluctuations by injecting local groundwater rich in nitrate-N (~15 mg/L). In-situ redox potential in shallow soils (40 cm depth) ranged from -600-600 mV, which is indicative of alternating conditions favorable for aerobic and anaerobic respiration. Redox potential increased upon saturation and declined again as soils drained, with more subtle changes occurring during the first wetting and drying cycle and greater changes occurring during repeated cycles. Pore water analysis shows mobilization of DOC and ammonium-N in shallow soils and removal of nitrate-N in sandy aquifer layers. More specifically, DOC, nitrate-N, ammonium-N, and nitrite-N were greatest in the organic soils and decreased down the column into the sandy aquifer layers. Toward the end of the experiment, the column was inundated with seawater collected from the Mediterranean to simulate a flooding event, causing an increase in all N-species concentrations below 10 cm as seawater transported the nitrogen and DOC contaminants to depth. In contrast, when the column was flooded from the bottom, nitrate-N concentrations decreased as the soils became saturated, oxygen was depleted, and denitrification occurred. Overall, we see how water table dynamics impact the fate and transport of nitrogen in groundwater as soils are repeatedly saturated from above and below.
A study on precipitation characteristics of Kal Baishakhi: a premonsoon thunderstorm event
Authors: Kannan Srinivasa Ramanujam
Published: February 2023

Kal Baishaki, a heavy thunderstorm event, recurs yearly during the premonsoon period (March-May) over the Indo-Gangetic plain and northeastern part of India. The event is highlighted by vigorous thunderstorm activity often associated with lightning and heavy to very heavy precipitation. Though the event has significant health and economic impact, the precipitation characteristics are not clearly understood. This is mainly due to a lack of continuous observation across a vast area covering West Bengal, Jharkhand, Orissa, Bihar, Assam, and other northeastern states of India. Precipitation measuring instruments onboard the Tropical Rainfall Measuring Mission satellite, followed by the Global Precipitation Measurement Mission, have provided an unprecedented data set that provides rainfall estimates at a high spatial, but sparsely temporal scale. The accuracy of data products has been refined over the years by comparing them with measurements from ground stations worldwide. The present work aims to consider rainfall data measured between 2001 and 2020 using remotely sensed instruments to analyse the precipitation characteristics of the significant rain event using a time series analysis approach.
Natural Dam Hazard in Kundasang, Sabah Mountainous Region
Authors: Abu Bakar Rabieahtul , Mohamad Zakaria , Jamaluddin Tajul Anuar , Razak Khamarrul Azahari
Published: February 2023

Natural dam built up in mountainous regions is hazardous definatively a potential disaster. Kundasang is located on the highest mount in Malaysia and was hit by the 2015 earthquake. There are numerous kinds of dams that form by natural processes, dams formed from landslides on a mountainous landscape present one of the potential threat to people and property. Landslide dams form in a wide range of physiographic settings. The most common types of mass movements that form landslide dams are rock and debris avalanches; rock and soil slumps and slides; and mud, debris, and earth flows. The most common initiation mechanisms for dam-forming landslides are excessive rainfall and earthquakes. Natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam.
Many landslide dams fail and mostly caused by over-topping as the most common cause of failure. The timing of failure and the magnitude of the resulting floods are controlled by dam size and geometry; material characteristics of the blockage; rate of inflow to the impoundment; size and depth of the impoundment; bedrock control of flow; and engineering controls such as artificial spill-ways, diversions, tunnels, and planned breaching by blasting or conventional excavation. One of the rare creation of landslide dams are when a single landslide sends multiple tongues of debris into a valley and forms two or more landslide dams in the same reach of river.
These dams pose hazards because back in 2015 there was an earthquake that shock the mount and destabilised the soil. Then, many trees were uprooted and fall. Thus, these phenomenon has shown in 2023 young vegetation has not stabilized mount Kinabalu slopes. There are many dam faces are steeper than the angle of repose, these dams and lakes are immediately downslope from steep crevassed glaciers and near-vertical rock slopes, and downstream from these dams are steep slopes with easily erodible materials that can be incorporated in the flow and increase flood peaks. The most recent reported failure mechanism is overtopping and breaching progressive rainfall.
Tracking magma intrusion and cooling in the lower crust with garnet Sm-Nd geochronology and phase diagram sections, Fiordland New Zealand
Authors: Stowell Harold , Bollen Elizabeth , Schwartz Joshua , Klepeis Keith
Published: February 2023

Garnet in the lower crust may grow during sub-solidus and hyper-solidus heating, and in some cases during cooling. Equilibrium phase diagram sections for mafic orthogneiss predict that the greatest volume of garnet should grow over a narrow temperature range with heating above the solidus. This peritectic garnet can preserve a record of multiple magma injections into complex magma mushes that form plutons in continental magmatic arcs. The exhumed lower crustal section from Fiordland New Zealand provides an ideal laboratory for using garnet to track processes in the continental magmatic arc within the Gondwana margin during the Cretaceous.The Western Fiordland Orthogneiss (WFO) dominates the inboard lower crustal section exposed in Fiordland. The three major plutons in the WFO preserve a range of igneous and metamorphic fabrics, with some of the oldest igneous foliations and magmatic contacts obvious in the central Misty Pluton and the youngest sub-solidus fabrics observed in the southernmost Malaspina Pluton which intruded c. 117 Ma based on zircon U-Pb ages. In the Malaspina Pluton, garnet Sm-Nd ages for ≥1 cm diameter peritectic garnet grains along cross-cutting trondhjemite veins range from 117.0±4.1 and 116.2±2.0 Ma for garnet cores (N=3), and from 115.8±2.6 to 108.0±2.0 Ma for bulk grains and rims (N=10). In contrast, garnet Sm-Nd ages for ≤0.5 cm diameter garnet grains from 3 locations In the Malaspina are 104.1±1.8, 106.2±2.1, and 103.6±2.2 Ma. Major and trace element zoning is compatible with insignificant volume diffusion in the large grains and significant compositional changes in the small grains. The Bloch et al. (2020) diffusion coefficients for Sm and Nd indicate that significant diffusion would cease at c. 700°C in small grains from the Malaspina Pluton; therefore, we calculate cooling rates of c. 21 (northeast) to c. 10°C (southwest) per m.y. The cooling ages combined with phase diagram sections and mineral thermobarometry indicate exhumation rates of 0.2 to 0.4 kbar per m.y. for the southwestern part of the Malaspina Pluton.Our results indicate that initial garnet growth ranged from near-synchronous to c. 4 m.y. after construction of the Malaspina Pluton by injection of magma sheets. We speculate that faster cooling in the northeastern Malaspina may have been driven by extension during growth of sub-solidus L-S tectonites which are best developed in this area. Combining these data with structural analysis and detailed evaluation of magma source compositions for individual sheets in WFO plutons allows us to evaluate magma plumbing systems for the Fiordland Arc.
Developing Drought Indicators for Assessing Multi-Sectoral Impacts Using a Systems Approach
Authors: Escriva-Bou Alvar , Dettinger Michael , Mount Jeffrey , Rosser Annabelle
Published: February 2023

California’s water storage and conveyance infrastructure—called the “water grid”—serves as a hedge against droughts. However, water operations—and more broadly the role of humans in reshaping drought risk and socio-environmental impacts—are usually not considered in characterizing drought status. The overall goal this project is to develop a framework for linking drought hazard indicators with sector-specific impacts in highly managed water storage and conveyance systems, such as those of the American West. To achieve this goal we have developed sector-specific drought hazard indicators for California that take into account water availability considering the built infrastructure, and management operations from both local and more distant water sources. After obtaining drought hazard indicators, we show case studies developing drought impact risk profiles for four sectors—agriculture, cities, small communities, and the environment—that reflect the capacity of these different sectors to respond and adapt to drought conditions.One of the most innovative parts of this project is the co-development of decision support tools. Working with five different stakeholder advisory groups—science, agriculture, cities, small communities and environment—we are identifying the usefulness of the indicators, and thresholds and triggers that can be tailored for local, state, and federal drought response.To conclude we will discuss the benefits and challenges of the current methodology, including data availability, the challenges associated with non-stationarity, and the co-development process with stakeholders.
Ionospheric Hole in the MLT Regions after Submarine Volcanic Eruptions
Authors: Khadka Sovit , Valladares Cesar , Gerrard Andrew
Published: February 2023

A gigantic submarine volcano erupted near Tonga Island on 15 January 2022 generating a tsunami and related atmospheric and oceanic waves across the globe. This violent volcano triggered extreme disturbances just above the volcanic center that reached near Earth’s stratosphere. This geophysical event generated acoustic-gravity waves to propagate upward and induce significant global perturbations and holes in the mesosphere and lower thermosphere (MLT) regions. Here, we study the MLT region’s response to the Tonga-induced perturbations using ground-based Global Positioning System (GPS)-total electron content (TEC) data from GPS receivers spread in the South American continent. The possible propagation mechanism of the Tonga-related ionospheric holes and perturbations mediated by neutral wind-driven dynamo fields, vertical drifts, and the contribution of geomagnetic conditions will also be discussed. 
Applicability of complex rainfall thresholds for Territorial Landslide Early Warning Systems (Te-LEWS) in the Himalayas
Authors: Siva Subramanian Srikrishnan , Sen Sumit , Yunus Ali. P
Published: February 2023

Increasing occurrences of landslides as compound events under extreme-rainfall demand the development of landslide early warning systems at the territorial scale. Traditionally, rainfall Intensity-Duration (ID) thresholds are adopted in these Territorial Landslide Early Warning Systems (Te-LEWS). However, the usage of complex rainfall thresholds in Te-LEWS has proven successful across the globe since these thresholds account for the terrain conditions in direct or indirect ways, unlike the ID thresholds which consider only the rainfall characteristics. In Japan, the Soil Water Index (SWI), a complex rainfall threshold, is implemented successfully to predict rainfall-induced sediment disasters. Implementing such complex thresholds in new geological settings is very challenging. Here, we present a framework to test the SWI threshold to predict shallow landslides and debris flows in the Himalayas. By analysing the landslides' historical occurrences and their corresponding triggering rainfall intensities from satellite-derived hourly precipitation data, we determine the critical threshold of SWI. The framework considers the SWI calculation within the desired region at every 5 km * 5 km grid. The approach is found applicable for selected rainfall-induced landslides and debris flows in the Himalayas, especially in Uttarakhand, India. This framework may be useful for establishing complex rainfall threshold-based Te-LEWS in new geological settings. 
Comparison of recent multi mission elevation change rates of Greenland and Antarctica
Authors: Helm Veit , Wenzel Hanna , Humbert Angelika
Published: February 2023

Mass changes of the polar Ice Sheets and their contribution to global mean sea level is an essential climate variable, critical for adaptation planning and important to understand the earth system in a warming climate. To ensure long term continuation of ice elevation and change records ESA proposed the Copernicus Polar Ice and Snow Topography Altimeter mission (CRISTAL) to be launched in 2027. CRISTAL, for the first time, will carry a dual-frequency altimeter in Ku and Ka Band to monitor changes in the height of ice sheets and glaciers and thickness of and snow on sea ice. Therefore, with the upcoming CRISTAL mission it is absolutely necessary to focus on sensor specific characteristics and its impact on elevation change records beforehand. To tackle these questions, we determine surface elevation change rates with a focus on the last decade of laser and radar altimetry observations using ICESat2, CryoSat-2, Sentinel-3 and SARAL/Altika. We investigate ice sheet wide and regional differences of elevation change rates derived from the four missions in the period from 2019 to 2022 with focus on different sensor characteristics (Laser/Ku/Ka Band), different acquisition/processing strategies ((P)LRM, SAR, SARIn), retracking (TFMRA,ICE1,ICE2) and orbit geometry (81.5°/88°).Our findings show that trend estimates of individual missions diverge most strongly at the margins and areas of complex topography but also in the flat interior of ice sheets and are highly dependent on the choice of retracker. We show that in order to determine volume changes as consistently as possible across missions, a uniform processing is required that includes backscatter/leading edge correction to suppress the influence of time-varying radar penetration due to changes in volume scattering.
Mapping the vegetation disturbances over the Tibetan Plateau
Authors: Wang Yanyu , Guo Hancheng , Xu Xiaoyong , He Yuhong , Shi Zhou
Published: February 2023

The Tibetan Plateau is one of the most sensitive areas responding to global environmental changes, especially global climate change, and has thus been deemed an important indicator of global change. The vegetated areas in Tibetan Plateau are expected to respond to environmental change because vegetation cover is a key part of the ecosystem. However, the vegetation disturbance behavior in the region remains poorly understood. Since the various change detection algorithms perform differently across complex natural systems, the combination of different approaches is currently a mainstream solution for better quantification of vegetation disturbances. The main objective of this study was to map the vegetation disturbances across the Tibetan Plateau using satellite data and a combination of change detection algorithms. We applied an ensemble strategy and satellite data to map the three decades of vegetation disturbances over the Tibetan Plateau. The two leading disturbance detection algorithms (Continuous Change Detection and Classification algorithm, CCDC; Landsat-based detection of Trends in Disturbance and Recovery algorithm, LandTrendr) were involved in the ensemble strategy with a Random Forests-based fusion for aggregating the classifiers. The reference data were taken from a total of 15,680 manually interpreted Landsat pixels, including 1,739 disturbed vegetation points, 3,696 stable vegetation points, and 10,245 non-vegetation points. It is found that a total area of about 105.83 M ha has experienced vegetation disturbance with considerable spatial variability across the Tibetan Plateau over the past three decades, and large differences among the disturbance patches were found. The identified unexpected scale of vegetation disturbance can further facilitate the understanding of the dramatic ecological changes in the ecologically fragile Tibetan Plateau region in response to climate change and more frequent human activities.
Feedbacks between sea-floor spreading,trade winds and precipitation in the Southern Red Sea
Authors: Stüwe Kurt , Robl Jörg , Turab Syed , Sternai Pietro , Stuart Fin
Published: February 2023

Feedbacks between climatic and geological processes are highly controversialand testing them is a key challenge in Earth sciences. The Great Escarpment ofthe Arabian Red Sea margin has several features that make it a useful naturallaboratory for studying the effect of surface processes on deep Earth. Theseinclude strong orographic rainfall, convex channel profiles versus concaveswath profiles on the west side of the divide, morphological disequilibrium influvial channels, and systematic morphological changes from north to souththat relate to depth changes of the central Red Sea. Here we show that thesefeatures are well interpreted with a cycle that initiated with the onset ofspreading in the Red Sea and involves feedbacks between orographic precipitation,tectonic deformation, mid-ocean spreading and coastal magmatism.It appears that the feedback is enhanced by the moist easterly tradewinds that initiated largely contemporaneously with sea floor spreading in theRed Sea.
Long term Paleogene increase in precipitation intermittency and intensity at mid-latitudes
Authors: Slawson Jacob , Plink-Bjorklund Piret
Published: February 2023

As the world warms due to rising greenhouse gas concentrations, the Earth system moves toward a climate state without societal precedent. Unmitigated scenarios of emissions produce climates like those of the Early Eocene by 2150 CE. Terrestrial records of rivers and floodplains from numerous Paleogene sedimentary basins in the US Western interior and Europe indicate an increase in flash floods and droughts at paleo mid latitudes, indicating increased precipitation intensity and intermittency. A global synthesis of Paleogene precipitation proxies allows us to reconstruct the timing of changes in hydroclimate from Paleocene to the Paleocene-Eocene Thermal Maximum (PETM) and through the Early Eocene Climatic Optimum (EECO). We observe that the largest shifts in hydroclimate are not linked to the PETM but rather occur during the warm late Paleocene and then at the end of the EECO. This is indicated by sedimentological proxies from paleo rivers and floodplains, paleosol geochemical proxies, and biological proxies. The sedimentological proxies indicate a shift from normal rivers, such as are characteristic at mid-latitudes today, to flood-prone rivers in late Paleocene, such as are characteristic in subtropics today. In the flood-prone Paleogene rivers sediment transport occurred during flashy floods. The rivers shifted back to normal at the end of the EECO. Paleocene and early Eocene paleosols indicate sustained droughts and intermittent seasonal rains. Biological proxies indicate large water table fluctuations and shifts in vegetation types. At PETM there is no change in the state of hydroclimate, but rather a further intensification of floods and droughts. These results show that current global warming is likely to cause intensification of precipitation intermittency and intensity at mid-latitudes with significant effects on water availability and agriculture. The most dramatic shifts in hydroclimate were not linked to the largest amplitude of atmospheric drivers at the PETM, but rather suggest a threshold-driven relationship between the atmospheric drivers and hydroclimate. This may suggest that significant changes in hydroclimate are to be expected already before 2150 CE. 
Reassessment of heat budget in the Mediterranean Seaand uncertainty in the probability distributions of heat fluxes
Authors: Ghani Mahmud Hasan , Ligouri Giovanni
Published: February 2023

In a semi-enclosed sea basin, like in the Mediterranean, determining the heat flux components of the heat budget is crucial for better understanding of the water budget and the regional climate. Due to its relatively small sea basin and existence of many islands, it’s always a complex and uncertain to settle with an accurate net heat balance. The variation in the net heat budget is referred as a heat budget “closure” problem, which has referred by many authors for the Mediterranean Sea. The value of net heat flux under this closure hypothesis should be negative, but there is a considerable range of variation for net heat budget in published literatures. In that context, we have computed the heat fluxes for in the Mediterranean Sea using a higher resolution atmospheric model analysis dataset (ECMWF) along with heat fluxes using a lower resolution dataset (ERA5) to compare. The computation of heat fluxes using high resolution ECMWF analysis dataset is a newer one for the Mediterranean Sea. The resulted long-term climatology of heat flux components (between ECMWF & ERA5) has shown a close agreement except a variation is observed in the Long Wave (LW) flux which matches a similar finding from Marullo et al. (2020). In addition to the net heat budget, this study aims to provide a newer aspect with the analysis of probability distributions of air-sea fluxes and uncertainty in those distributions. We have investigated the probability distributions of heat fluxes on the base of computed air-sea fluxes time series. We have analysed the probability distributions of air-sea fluxes using atmospheric analysis and reanalysis datasets and fitted with three parameters Probability Density Function (PDF). Then, we have evaluated the applied theoretical PDF fits with observed heat fluxes that have indicated areas with uncertainty through our statistical modelling approach for the turbulent heat flux distributions. The statistical analysis of air-sea fluxes is not a usual one for the Mediterranean Sea but an important one to obtain the statistical inference of air-sea flux distributions in relation to the probable uncertainty arises in the ocean forecasts. 
The Stability Transition from Stable to Unstable Frictional Slip with Finite Pore Pressure
Authors: Affinito Raphael , Elsworth Derek , Marone Chris
Published: February 2023

Pore fluids are ubiquitous throughout the lithosphere and are commonly cited as a major factor producing slow slip and complex modes of tectonic faulting. Here, we investigate the role of pore pressure on slow slip and the frictional stability transition and find that the mode of fault slip is largely unaffected by pore pressure once we account for effective stress. Ambient temperature experiments are done on synthetic fault gouge composed of quartz powder with a median grain size of 10μm with an average permeability of  8E-17m2 – 6E-18m2 from shear strains 0 - 26. We conduct constant velocity experiments at 20MPa σn’, with Pp/σn’ratios of λ from 0.05 to 0.28. Under these conditions, dilatancy strengthening is minimal and we find that slip rate dependent changes in the critical rate of frictional weakening are sufficient to explain slow slip.
Understanding the hydrological drought processes in the Paraná River Basin.
Authors: Cuartas Luz Adriana , Fujita Thais , Andrade Campos Juliana , Cunha Ana Paula , Berttachi Uvo Cintia , Broedel Elisangela , Marengo José Antonio
Published: February 2023

Brazil has endured the worst droughts in recorded history over the last decade, resulting in severe socioeconomic and environmental impacts. The country relies heavily on water resources, with 77.7% of water consumed for agriculture (irrigation and livestock), 9.7% for industry, and 11.4% for human supply. Hydropower plants generate about 64% of all electricity consumed. One of the most impacted basins was the Paraná River basin It concentrates a third of the Brazilian population in urban centres such as São Paulo, the largest city in Latin America, thus it is the river basin with the greatest demand in the country. This basin is also the most important in hydropower generation, by the highest install capacity for hydropower; 57 reservoirs in the main steam and its tributaries (Grande, Paranaíba, Tietê, Paranapanema and Iguaçu Rivers), with Itaipu having the largest installed capacity (14,000 MW). This study aimed to advance the state of knowledge regarding hydrological drought patterns in the Paraná River Basin for improved monitoring and forecasting.
Droughts, like all hydrometeorological processes, are multivariate processes, that is, they are the result of the interaction of multiple hydrometeorological, climatic, and anthropogenic variables, among others. Therefore, several studies have shown the need to consider a multivariate approach to analysis and modelling drought events, which allows a better evaluation of the characteristics and conditions of its.
In this study we applied: i) well know univariate drought index: SPI, SPEI and SSFI; ii) a multivariate index, obtained through the Copulas Theory and; iii) potential soil moisture conditions obtained through the Normalized Terrain Model HAND, to understand and characterized hydrological droughts in the Paraná River Basin and Subbasins. We used rainfall data from CHIRPS, streamflow data obtained from the Brazilian National Electrical System Operator (ONS) and the National Water and Sanitation Agency (ANA), the SPEI global drought monitor dataset and HAND MERIT dataset (90 m spatial resolution).
The results show that the hydrological droughts in the last decade of 1981–2021, were the most severe and intense. Among the indices, SPEI, SSFI and the multivariate index, presented the strongest evidence, at time scales of 12, 24, 36 and 48 months. The multivariate index together with HAND information allow us to understand better the process of developing, duration, and recovery of drought events.
A Preliminary Green Function Database for Global 3-D Centroid Moment Tensor Inversions
Authors: Sawade Lucas , Ding Liang , Peter Daniel , Gharti Hom Nath , Liu Qinya , Nettles Meredith , Ekström Göran , Tromp Jeroen
Published: February 2023

Currently, the accuracy of synthetic seismograms used for Global CMT inversion, which are based on modern 3D Earth models, is limited by the validity of the path-average approximation for mode summation and surface-wave ray theory. Inaccurate computation of the ground motion’s amplitude and polarization as well as other effects that are not modeled may bias inverted earthquake parameters. Synthetic seismograms of higher accuracy will improve the determination of seismic sources in the CMT analysis, and remove concerns about this source of uncertainty. Strain tensors, and databases thereof, have recently been implemented for the spectral-element solver SPECFEM3D (Ding et al., 2020) based on the theory of previous work (Zhao et al., 2006) for regional inversion of seismograms for earthquake parameters. The main barriers to a global database of Green functions have been storage, I/O, and computation. But, compression tricks and smart selection of spectral elements, fast I/O data formats for high-performance computing, such as ADIOS, and wave-equation solution on GPUs, have dramatically decreased the cost of storage, I/O, and computation, respectively. Additionally, the global spectral-element grid matches the accuracy of a full forward calculation by virtue of Lagrange interpolation. Here, we present our first preliminary database of stored Green functions for 17 seismic stations of the global seismic networks to be used in future 3-D centroid moment tensor inversions. We demonstrate the fast retrieval and computation of seismograms from the database.
Mass transport induced by nonlinear surface gravity waves
Authors: Grzonka Laura , Cieślikiewicz Witold
Published: February 2023

As waves pass, fluid elements experience not only periodic motion but also a movement in a direction of wave propagation (Stokes, G.G. (1847) On the Theory of Oscillatory Waves. Transactions of the Cambridge Philosophical Society, 8, 441-455). Defined as a difference between the average Lagrangian flow velocity of a particle and the average Eulerian flow velocity of the fluid, the Stokes drift entails, amongst others, the existence of wave-induced mass transport (van den Bremer TS, Breivik Ø. 2017 Stokes drift. Phil. Trans. R. Soc. A 376:20170104. http://dx.doi.org/10.1098/rsta.2017.0104). Knowledge of it is of high significance since it allows one to calculate tracer transport, for instance, plastic or oil pollution.While operating in the Eulerian frame of reference, one should recognize that a fixed point in space in the vicinity of a free surface emerges and submerges under the water during wave motion. This phenomenon is called the emergence effect and it does impact the particle kinematics properties. Cieślikiewicz & Gudmestad developed a method of calculating the wave-induced mass transport for deterministic and random waves taking into account the emergence effect (Cieślikiewicz, W. & Gudmestad, O. T. (1994). Mass transport within the free surface zone of water waves. Wave Motion, 19(2), 145–158. https://doi.org/10.1016/0165-2125(94)90063-9).The goal of the study was to introduce numerical examples and verification of both deterministic and random wave cases presented by Cieślikiewicz & Gudmestad (1994) depending on wind wave parameters. Wolfram Mathematica software was used to carry out the calculations and draw figures. The wave energy spectrum was determined using the JONSWAP formula (Hasselmann, K., Barnett, T. P., Bouws, E., Carlson, H., Hasselmann, D. E., Kruseman, P., Meerburg, A., Mûller, P., Olbers, D. J., Richter, K., Sell, W., & Walden, H. (1973). Measurements of wind-wave growth and swell decay during the Joint North Sea Wave Project (JONSWAP). Ergaenzungsheft Zur Deutschen Hydrographischen Zeitschrift, Reihe A., 12(A8), 1–95). The results show that the mass transport values for a representative deterministic wave agree with values for random waves. Therefore, the deterministic wave formulas may be used to initial estimate mass transport induced by random water wave field.