bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of volcanic sources and evolution of stress and strain rate at Campi Flegrei caldera (Italy) from GNSS data (2000-2022)
Authors: Bruno Valentina , De Martino Prospero , Dolce Mario , Mattia Mario , Montgomery-Brown Emily K.
Published: February 2023

The Campi Flegrei caldera (southern Italy) is one of the most populated volcanic areas on the Earth. It is characterized by intense uplift episodes followed by subsidence phases. Following the 1982–1984 unrest, there was about 21 years of subsidence,  followed by a new phase of inflation started in 2005 and, with increasing uplift rates over time, is still ongoing. Since 2005, the total vertical ground displacement is about 1 m near the city of Pozzuoli.We analyze the evolution of the volcanic sources that caused the measured ground deformations since 2000 by modelling the Global Navigation Satellite System (GNSS) data from the permanent monitoring network in the caldera. Based on changes in slope in the GNSS displacement time series, we divide the recent inflation period into different phases. During time periods characterized by a near-linear trend, we can infer that a stationary pressure source is active inside the caldera. Using this inference, we describe the ground deformations of the last two decades through different sub-intervals, as “snapshots” that are the result of the time evolution of the inner volcano-dynamics.Furthermore, over the investigated period we analyze the evolution of surface stresses from an ellipsoidal source model and the strain rate patterns from the horizontal GNSS velocities. In particular, we compute areal strain rates, shear strain rate magnitudes, associated with a strike-slip component of deformation, and rotation rates, and this helps us to infer surface manifestations of subsurface deformations.
Detection of Deep Low-Frequency Tremors from Continuous Paper Records at a Station in Southwest Japan About 50 Years Ago Based on Convolutional Neural Network
Authors: Nagao Hiromichi , Kaneko Ryosuke , Ito Shin-ichi , Tsuruoka Hiroshi , Obara Kazushige
Published: February 2023

The establishment of the High Sensitivity Seismograph Network (Hi-net) in Japan has led to the discovery of deep low-frequency tremors. Since such tremors are considered to be associated with large earthquakes adjacent to tremors on the same subducting plate interface, it is important in seismology to investigate these tremors before establishing modern seismograph networks that record seismic data digitally. We propose a deep-learning method to detect evidence of tremors from seismogram images recorded on paper more than 50 years ago. In this study, we trained a convolutional neural network (CNN) based on the Residual Network (ResNet) with seismogram images converted from real seismic data recorded by Hi-net. The CNN trained by fine-tuning achieved an accuracy of 98.64% for determining whether an input image contains tremors. The Gradient-weighted Class Activation Mapping (Grad-CAM) heatmaps for visualizing model predictions indicated that the CNN successfully detects tremors without being affected by teleseisms. The trained CNN was applied to the past seismograms recorded from 1966 to 1977 at the Kumano observatory, in southwest Japan, operated by Earthquake Research Institute, The University of Tokyo. The CNN showed potential for detecting tremors from past seismogram images for broader applications, such as publishing a new tremor catalog, although further training using data including more variables such as the thickness of the pen would be required to develop a universally applicable model.
Modelling of cloud electrification
Authors: Popová Jana , Sokol Zbynek
Published: February 2023

We developed a cloud electrification model (CEM) which describes the evolution of the electric field in clouds, including electric discharges. Our CEM simulates evolution of charge of individual hydrometeors (cloud droplets, rain droplets, ice, snow, graupel) and models the distribution of positive and negative ions. Using this model, we compared the evolution of electric charge and electric field for selected winter and summer thunderstorms that occurred close to the Milešovka meteorological observatory. We analysed the dataset of thunderstorms using measurements of Ka-band cloud profiler and X-band weather radar, both located at the Milešovka observatory, and standard meteorological measurements. The analyses include a comparison of the structure of the modelled thunderstorms with the structure derived from radar and satellite observations. 
Evaluating the influence of African dust in West African rainfall through Earth observation
Authors: Estebanez Camarena Monica , ten Veldhuis Marie-Claire , van de Giesen Nick
Published: February 2023

Food and economic safety in West Africa rely heavily on rainfed agriculture and are threatened by climate change and demographic growth. Accurate rainfall information is therefore crucial to ensure safety against these challenges. However, existing rainfall models fail to accurately represent the highly variable and sparsely monitored West African rainfall distribution. Satellite rainfall products show a poor correlation with ground-based rainfall measurements and literature suggests that atmospheric aerosols are partly to blame for this poor performance.

West Africa presents higher airborne aerosol concentrations than other regions of the world, mainly originating from dust outbreaks in the Sahara Desert and biomass burning across the Atlantic Ocean in South and Central Africa. Furthermore, climate in West Africa is modulated by the movement of the Intertropical Convergence Zone (ITCZ), that separates a hot, dry and dusty air mass from the Sahara Desert from a cold and humid air mass from the Atlantic Ocean. The ITCZ marks the transition between the dry and the rainy season in the reigon.

In this work we study the relationship between atmospheric dust during the dry and the rainy season and precipitation in West Africa using Google Earth Engine. We employ IMERG precipitation data for West Africa and aerosol data from the TROPOMI instrument on-board Sentinel 5P over the whole of Africa between 2018 and 2022, to capture the largest sources of airborne aerosols reaching West Africa throughout the year. We investigate precipitation on a 0.5 degree resolution grid covering West Africa and part of the adjacent Atlantic Ocean and spanning over all West African climatic regions, from the Sahara in the North to the Guinean and Guinean-Congolian regions in the South. We analyze regional and remote aerosol-precipitation connections at different temporal and spatial scales and for the different climatic regions.

The aim of this research is to further the knowledge about the relationship between African dust and West African rainfall so we can better account for and reproduce these processes in satellite rainfall retrieval models.  
Response of the Benguela upwelling system to four decades of global warming
Authors: Talaat Salama Amr , Zavatarelli Marco , Butenschön Momme , Lovato Tomas
Published: February 2023

The Benguela upwelling system (BUS) is one of the most productive marine systems in the world oceans, with about 50 times the productivity per unit area compared to the global ocean average. Such high productivity is attributed to the upwelling process, in which Equatorward alongshore winds combined with the Coriolis effect force surface coastal water offshore, resulting in bringing deep, cold, nutrient-rich waters up to the photic layer, triggering the primary production. The BUS is highly likely to be affected by global warming. Nevertheless, it’s response seems complex because warming might affect the system by two counteracting ways. First, as warming proceeds, upwelling favorable winds might intensify leading to stronger upwelling events. On the other hand, increased stratification potentially counteracts the efficacy of upwelling to deliver nutrients to surface layers. Overall, such possible alterations could have drastic impacts on the physical and biogeochemical characteristics of the BUS and primarily the primary productions rates. Thus, investigating the response of the BUS to recent global warming is crucially important.To this purpose, a coupled highly resolved 3D physical-biogeochemical model is implemented based on NEMO (Nucleus for European Modelling of the Ocean) and BFM (Biogeochemical flux model). The coupled model is being constructed via an online nesting approach to maintain high resolution for a small-scale process like the upwelling, but at the same time to provide the Benguela domain precise boundary conditions. The grid refinement has been conducted using AGRIF (Adaptive Grid Refinement in Fortran). A two-way online nesting has been applied, where information from the child is allowed to propagate back into the parent domain. With a tripolar ORCA025 grid, the nesting (parent) domain covers the global ocean with a horizontal resolution of 1/4°, while the nested (child) domain for the Benguela domain has a resolution of 1/16° and spatially extend from (7°W to 27°E) and from (15°S to 44°S). Both grids have 75 vertical layers. The coupled model is run over a hindcast simulation encompassing four decades starting from 1980 to 2020.Regarding the model’s set-up, bottom topography is being derived from GEBCO, while the atmospheric forcing has been retrieved from ERA5, and due to the significance of river freshwater input in such simulation, the coupled model was forced with runoff data from the Global Flood Awareness System (GLOFAS). As for the BFM model configuration, it comprises multiple plankton functional groups, nutrients forms, and O2 dependent processes. BFM initial conditions were retrieved from The Global Ocean Data Analysis Project (GLODAP). Finally, the coupled model is validated using in situ and satellite observational data for physical and biogeochemical state-variables and processes.
Trace gas retrievals from infrared emission spectrometry in the Arctic
Authors: Heizmann Lukas , Palm Mathias , Notholt Justus , Buschmann Matthias
Published: February 2023

Trace gas measurements are routinely performed using ground-based solar absorption spectroscopy in measurement networks such as NDACC (Network for Detection of Atmospheric Composition Change) and TCCON (Total Carbon Column Observing Network). For water vapour there exist radiosonde measurements providing high vertical resolution but limited temporal resolution. Retrievals from infrared emission spectrometry bridge a temporal gap in the measurement of trace gases during polar night. Measurements are possible dayround under cloud free conditions. At the AWIPEV site in Ny-Ålesund, Svalbard, we deploy a Bruker Vertex 80 FTIR emission spectrometer with a maximum resolution of 0.08 cm⁻¹ which is able to resolve individual spectral lines. We present optimal estimation retrievals of water vapour and methane. The results are compared to daily radiosonde measurements and TCCON retrievals. First results of applying our retrieval to emission spectra with a reduced resolution are also shown. This will in the future allow to include the retrieval on E-AERI-type instruments with their lower resolution deployed e.g. during the MOSAiC campaign.
Stationarity Assessment of Precipitation and Temperature Extremes in the Continental United States
Authors: Teegavarapu Ramesh , Sharma Priyank , Li Diego
Published: February 2023

Stationarity assessments of annual extremes of monthly precipitation and minimum, average, and maximum temperatures at over 1200 sites in the U.S. are carried out using a nonoverlapping block stratified random sampling approach. The approach uses random partitioning of the time series into several blocks to assess different forms (i.e., weak, strong) of stationarity using nonparametric two-sample and multi-sample hypothesis tests. This approach's assessment of stationarity is compared with those derived from nonparametric Spearman’s rank correlation and variants of Mann-Kendall tests considering seasonality and autocorrelation. Monthly data of precipitation and temperature obtained from the United States Historical Climatology Network (USHCN) for the period 1910-2019 are used for this analysis. Tests (e.g.,  Augmented Dickey-Fuller (ADF) and Kwiatkowski-Phillips-Schmidt-Shin (KPSS)) specifically geared for stationarity assessments in econometrics and time series forecasting are also used for comparative assessment. Discrepancies in assessments from the nonparametric tests, ADF and KPSS, and nonoverlapping random sampling approach are noted in the number of sites. The random sampling approach used in the current study provides a robust assessment of stationarity considering the different characteristics of the hydroclimatic time series.
A Climate Data Record of Global Sea-Ice Drift from the EUMETSAT OSI SAF
Authors: Down Emily , Lavergne Thomas
Published: February 2023

Sea-ice drift is a key variable for understanding sea ice in a changing climate, and an Essential Climate Variable (ECV) product for the Global Climate Observing System (GCOS). In the Arctic, sea ice has been reported to drift faster in recent years (e.g. Rampal et al., 2009), associated with its reduction in area, thinning, and loss of multiyear ice. In the Antarctic, trends in sea-ice drift have been linked to trends in wind patterns (e.g. Hollands and Kwok, 2012). In this contribution, we present a new 30-year Climate Data Record (CDR) of global, year-round sea-ice drift vectors covering 1991 to 2020. This uses the continuous maximum cross-correlation technique (CMCC) for measuring sea-ice drift from pairs of brightness temperature images of passive microwave satellite missions (Lavergne et al., 2010). During summer, this technique becomes less accurate due to surface melting and higher atmospheric humidity. We therefore employ a parametric free-drift model to fill the data gaps in the summer. This model calculates the ice drift based on wind vectors from the ERA5 wind reanalysis, under the assumption that the internal stresses of the ice can be neglected. We describe the algorithm baseline for the new CDR as well as results of validation against the sparse network of on-ice buoy trajectories. We finally describe the merits and known limitations of the new data record. This CDR was created in the context of the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) and is readily available at https://doi.org/10.15770/EUM_SAF_OSI_0012.References:Holland, P., Kwok, R. Wind-driven trends in Antarctic sea-ice drift. Nature Geosci 5, 872–875 (2012). https://doi.org/10.1038/ngeo1627Lavergne, T., Eastwood, S., Teffah, Z., Schyberg, H., and Breivik, L.-A. (2010), Sea ice motion from low-resolution satellite sensors: An alternative method and its validation in the Arctic, J. Geophys. Res., 115, C10032, doi:10.1029/2009JC005958.Rampal, P., Weiss, J., and Marsan, D. (2009), Positive trend in the mean speed and deformation rate of Arctic sea ice, 1979–2007, J. Geophys. Res., 114, C05013, doi:10.1029/2008JC005066. 
Quantifying massive cascading sediment transport triggered by a cliff fall in a highly-active alpine basin.
Authors: Barbosa Natalie , Leinauer Johannes , Jubanski Juilson , Dietze Michael , Münzer Ulrich , Siegert Florian , Krautblatter Michael
Published: February 2023

In the coming decades with enhanced rainstorm activity, massive sediment redistribution in Alpine catchments will be a key hazard and challenge in Alpine communities. While several studies have collected data from massive rock slope failures, few studies have quantitatively assessed the cascading sediment redistribution in highly active alpine catchments. Recurrence intervals for cliffs falls are estimated at 80 years (Krautblatter et al., 2012 ), thus, observations of the subsequent sediment cascading are limited or inexistent despite their major role in landscape evolution and sediment fluxes. Digital aerial photogrammetry acquired by governmental agencies is becoming a relevant tool to better understand short landscape response to climate change. Repetitive yearly to bi-yearly orthophotos and DSM extracted from large format aerial surveys represent a valuable monitoring tool at regional scale because of their wide extent coverage (km) at a high spatial resolution (20 cm). This contribution reports the massive sediment redistribution that has been triggered by the multistage failure of >200.000 m³ from the Hochvogel dolomite peak during the summer of 2016. Seven true orthophotos and high-resolution aerial photogrammetric digital surface models (DSM) between 2010 and 2020 were 3D coregistered to a reference system for optimized volume calculation in steep terrain. Three consecutive differential DSMs (2010-2012, 2012-2014, 2014-2015) describe the catchment morphodynamics before the cliff fall, while, the subsequent differential DSMs (2015-2017, 2017-2018, 2018-2020) describe the morphodynamics one year, two years and four years after the cliff fall. Spectrograms from surrounding seismic stations expand the understanding of the cliff fall timing. We observe the decadal throughput of >200.000 m³ of sediment with massive sediments pulses that (i) respond with reaction times of 0-4 years and relaxation times beyond 10 years, (ii) with faster 0-2 years response times in the upper catchment (A&B) and >>2 years response times in the lower catchments, (iii) the inversion of sedimentary (>10²-10³ mm/a) to massive erosive regimes (>10² mm/a) within single years and vice versa and the (iv) dependency of redistribution to rainstorm frequency and intensities. Krautblatter, M., Moser, M., Schrott, L., Wolf, J., Morche, D., 2012. Significance of rockfall magnitude and carbonate dissolution for rock slope erosion and geomorphic work on Alpine limestone cliffs (Reintal, German Alps). Geomorphology 167, 21–34. https://doi.org/10.1016/j.geomorph.2012.04.007
Adapting Energy Systems to a Changing Climate - A Destination Earth Use Case
Authors: Schyska Bruno , Ceglarz Andrzej , Hayez Léa , Kies Alexander , Schroedter-Homscheidt Marion , Medjroubi Wided
Published: February 2023

In liberalized electricity markets, the planning and operation of the electricity grids, often, is done by private companies under the control of a public authority. Following their mandates, the European transmission system operators for electricity implement, among other analyses, national grid extension plans, the Europe-wide Ten-Year Network Development Plan and the European Resources Adequacy Assessment. To achieve evidence-based decision-making, they rely on the best-available meteorological and/or climatological information on a variety of scales, from the local distribution grid level to the European transmission system, and from short-term forecasts for the operation to climate scenarios for investment decisions. Here, the capabilities of the new DestinE Digital Twin on climate adaption can make a significant impact. It is expected that the explicit modelling of physical processes on the storm- and cloud-resolving scale also leads to a more realistic and accurate representation of the solar and wind resources. This offers great opportunities for improved energy system modelling and opens the door for new innovative approaches for adding the analysis of climate information into standard modelling workflows applied in the energy sector. However, there is a lack of knowledge about available meteorological data sets, their characteristics and the implications of using different data sets for grid planning and adequacy assessment activities in the user community. Standardized tools and methods to add the analysis of climate change and/or climate uncertainty to user workflows rarely exist. This hinders energy system modelers to make full use of the available meteorological information and, consequently, prevents users from tapping the full potential of the data. As energy systems become more dependent on weather, and as the uncertainties about climate change impacts rise, the operation and planning of integrated energy systems becomes an increasingly complex task.Aim of this presentation is the introduction of a DestinE Use Case for the energy sector jointly implemented by DLR, the Renewables Grid Initiative (RGI) and Aarhus University. This Use Case will develop a representative Demonstrator exemplarily showcasing the use of climate information in the energy sector for grid planning and resources adequacy assessment purposes, and equip the user community with the tools, methods and the knowledge needed to ensure the safe and clean supply of energy in Europe in accordance with the Nationally Determined Contributions to the Paris Agreement and the European Union’s “Fit for 55” goals.
Overturning and heat transport variations in the South Atlantic in an ocean reanalysis ensemble and other estimates
Authors: Baker Jonathan , Renshaw Richard , Jackson Laura , Dubois Clotilde , Iovino Doroteaciro , Zuo Hao , Perez Renellys , Dong Shenfu , Kersalé Marion , Mayer Michael , Mayer Johannes , Speich Sabrina , Lamont Tarron
Published: February 2023

The variability of the South Atlantic meridional overturning circulation and meridional heat transport measured across 34.5°S during 2013–2017 differs significantly between observational and ocean reanalysis estimates. Variability in an ocean reanalysis ensemble and an eddy-resolving reanalysis is similar to an altimeter-based estimate, but smaller than energy-budget and mooring-based estimates. Over 1993–2020, there is no long-term trend in the ensemble-mean overturning and heat transport, although there are inter-model differences, whereas the altimeter-based and energy-budget estimate transports increase over this period. Time-mean overturning volume transport (and the depth of maximum overturning) across 34.5°S in the ensemble and observations are similar, whereas the corresponding mean heat transports differ by up to 0.3 PW. The seasonal cycle of these transports varies between estimates, due to differences in the methods for estimating the geostrophic flow and the sampling characteristics of the observational approaches. The baroclinic, barotropic and Ekman MOC components tend to augment each other in mooring-based estimates, whereas in other estimates they tend to oppose each other so the monthly-mean, inter-annual and seasonal MOC anomalies have a greater magnitude in the mooring-based estimates. Thus, the mean and variation of real world South Atlantic transports, and the amplitude of their fluctuations, are still uncertain. Ocean reanalyses may be useful tools to understand these differences and the mechanisms that control volume and heat transport variability in the South Atlantic, a region critical for determining the global overturning pathways and inter-basin transports.   
Radiative impact of long-lived halocarbons and their atmospheric trends, derived from 15 years of IASI/Metop measurements
Authors: De Longueville Hélène , Clarisse Lieven , Whitburn Simon , Clerbaux Cathy , Coheur Pierre
Published: February 2023

In addition to being harmful to the ozone layer (for chlorinated and brominated compounds), halocarbons are also potent greenhouse gases. Their monitoring is therefore essential. Here we exploit measurements from the infrared satellite sounder IASI which offers the potential to robustly assess trends in the atmospheric abundances of trace gases owing to the stability and the consistency of the measurements made by three successive instruments over a period of more than 15 years. Despite their weak spectral signatures, we have recently reported the detection of eight long-lived halocarbons in IASI spectra: CFC-11, CFC-12, HCFC-22, HCFC-142b, HFC-134a, CF4, SF6 and CCl4.In this work we exploit the available record of continuous IASI measurements to (1) determine the temporal evolution in atmospheric abundance of these species (2) quantify their radiative impact for the first time. We calculate their global radiative forcing based on integration over specific bands of IASI spectrally resolved fluxes (Whitburn et al., 2020[1]). Our results are validated with ground-based measurement networks and other remote sensors data. We conclude by assessing the usefulness of IASI and follow-on missions to contribute to the global monitoring of CFCs and their substitutes.
[1] Whitburn, S. et al. Spectrally resolved fluxes from IASI data: retrieval algorithm for clear-sky measurements. J. Clim. 33, 6971—6988 (2020).
Implications of governance mechanisms for spanning boundaries and managing risk
Authors: Cumiskey Lydia , McCullagh Denise , Schweizer Pia-Johanna , Bharwani Sukaina
Published: February 2023

Managing flood risk and adapting to climate change is complex where multiple actors need to work together across sectoral and disciplinary boundaries to capture synergies and manage trade-offs. A selection of governance mechanisms were found to influence actors’ capacity to work in partnership, break down silos and unlock opportunities.Results from research conducted within the SYSTEM-RISK project identifies boundary spanning roles as governance mechanisms facilitating integrated flood risk management in England and Serbia (Cumiskey, 2020). Among other characteristics, the ‘reticulist’ was found to utlise networks and diplomacy to access funding, ‘entrepreneurs’ acted creatively to capture funding and test the flexibility of rules, ‘interpreters’ built interpersonal relationships and interpreted different professional languages, ‘organisers’ managed actor partnerships and ‘specialists’ were willing to engage and try new approaches. The availability of rules and resources influenced capacities to hire, train and sustain such boundary spanning staff.  Results highlighting the dynamic interdependencies between such roles and the governance system will be shared.Place-based adaptation partnerships were found as another governance mechanism, strengthening collaboration, knowledge exchange and joint action across boundaries. The Climate Adaptation Partnership Framework1 was developed through the TalX project (Transboundary Adaptation Learning Exchange) to collate learning from applications in Ireland, Northern Ireland, Scotland, England and Wales and provide guidance for stakeholders interested in implementing such partnerships.  The RISK-TANDEM framework is being developed within the DIRECTED project (Horizon Europe, 2022 - 2026) to enhance risk governance, knowledge co-production and interoperability across data, models and tools to enable disaster resilience in four Real World Lab regions. An initial version of the framework, which builds upon the existing Tandem Framework2 (among others) will be shared along with plans for implementation.   The role of such governance mechanisms in integrating research, innovation and science in a collaborative way will be introduced, while opening the discussion on how to improve the application of such mechanisms to facilitate future engaged research. Cumiskey, L. (2020). Embracing boundary spanning roles in Flood Risk Management. PhD Research Briefing Note 2. Middlesex University. Available at: https://eprints.mdx.ac.uk/30418/ 1 Climate Adaptation Partnership Framework. Available at: https://talx2020.github.io/ 2 The Tandem framework: a holistic approach to co-designing climate services. Available at: https://www.weadapt.org/knowledge-base/climate-services/the-tandem-framework
Divergent responses of grassland vegetation phenology to climate change at different scales
Authors: Ren Shilong
Published: February 2023

Understanding grassland phenology responses to climate change is of crucial importance for revealing regional and species differences in ecosystem processes. By means of thousands of ground observations and the counterparts derived from long-term remote sensing data, the spatiotemporal patterns of grassland phenology and its links to climate changes and biotic factors were investigated over the Northern Hemisphere. In site-species scale, the leaf-out date did not show significant variation trend for 68.6% of the site-species, while the leaf senescence date has significantly delayed for 31% of the site-species during 1982-2011 over China. Sunshine hours, temperature, precipitation, and the leaf-out date primarily explained the variation of leaf senescence for 36.6%, 31.7%, 22.0%, and 9.8% of the investigated site-species, respectively. Sunshine hours were the foremost factor in controlling leaf senescence for 60.1% of graminoid species and temperature for 42.3% of forb species. Specifically, in the Inner Mongolia Grassland, a predominant significant positive correlation between the leaf-senescence date and previous precipitation in 54.6% of site species. In pixel-landscape scale, a significant advance (P < 0.05) of the start of growing season (SOS) was detected in 23.2% of grid cells, while a predominantly and significantly delaying trend (P < 0.05) of the end of growing season (EOS) was identified in 20.5% of grid cells during 1981–2014 over the grasslands in the Northern Hemisphere. They jointly resulted in a primarily significant prolongation trend of growing season length in 22.7% of grid cells. Meanwhile, the time span of SOS/EOS (from the earliest SOS/EOS to the last SOS/EOS) and the growing season length (from SOS to EOS) have extended for the entire study region. For the Inner Mongolia Grassland, SOS was mainly controlled by pre-SOS precipitation with the sensitivity being largest in desert steppe. EOS was closely connected with pre-EOS air temperature in meadow steppe and typical steppe, but more closely related to pre-EOS precipitation in desert steppe. Moreover, a significant negative correlation between EOS and SOS was observed in part of grassland areas, but no significant relationship between NPP and EOS was observed. Aside from correlation analysis, a newly model by incorporating the effect of drought stress (CDDP) into the traditional chilling-degree-days (CDD) model was developed to simulate the leaf senescence. CDDP model was selected as the optimal model for 73% of site species with insufficient water supply in preseason, while CDD model was selected as the optimal model for 18% of site species with a relatively wet but cold preseason. Overall, they highlight the diverse responses in the timing of spring and autumn phenology to preceding temperature and precipitation in different grassland types and their dependence on species, functional-types, and geographical gradients. 
Inertial sensing using Very Long Baseline Atom Interferometry
Authors: Gupta Vishu , Tell Dorothee , Lezeik Ali , Montero Mario , Stojkovic Constantin , Klussmeyer Jonas , Zipfel Klaus , Bode Sebastian , Albers Henning , Schubert Christian , Rasel Ernst M. , Schlippert Dennis
Published: February 2023

Quantum sensors based on atom interferometry allow the high-precision measurement of fundamental physical properties. The Very Long Baseline Atom Interferometry (VLBAI) facility in the Hannover Institute of Technology is working towards the measurement of inertial effects, which can be used for tests of fundamental physics and metrology. The sensitivity of atom interferometers depends on several factors one of which being the interferometer time and the large base- line of VLBAI facility provides longer interferometer time which leads to higher sensitivity.Here we present the current status of the 15 m high VLBAI facility which aims for sub nm/s2 gravity measurement sensitivity. It includes a 10 m high magnetically shielded baseline to reach gradients below 1.5nT/m and a seismic attenuation system for inertial referencing which allows for excellent control over external perturbations of the inertial reference mirror. The long baseline at the VLBAI facility uses rubidium and ytterbium BEC source based atom interferometers with possible interferometer time of 2.8s. After the demonstration of small-scale interferometer, the rubidium BEC source is currently being inserted as fountain source on long baseline.This work is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation): Project-ID 274200144 - SFB 1227 DQ-mat (projects B07 and B09), Project-ID 434617780 - SFB 1464 TerraQ (project A02), and Germany’s Excellence Strategy - EXC-2123 QuantumFrontiers - Project-ID 390837967.
Automatic global building completeness assessment of OpenStreetMap using remote sensing data
Authors: Oostwegel Laurens Jozef Nicolaas , Garcia Ospina Nicolas , Evaz Zadeh Tara , Shinde Simantini , Schorlemmer Danijel
Published: February 2023

OpenStreetMap (OSM) is the largest crowd-sourced mapping effort to date, with an infrastructure network that is considered near-complete. The mapping activities started as any crowd-sourced information platform: the community expanded OSM anywhere there was a collective interest. Initial efforts were found around universities, hometowns of mappers and areas designated by organizations like the Humanitarian OSM Team (HOT). This resulted in a map that is of non-uniform completeness, with some areas having all building footprints in, while other areas remain incomplete or even untouched. Currently, with 530 million footprints, OSM identifies between a quarter and half of the total building footprints in the world, if we estimate that there are around 1-2 billion buildings in the world.A global view on the completeness of buildings existing in OSM did not yet exist. Unlike other efforts, that only look at a subset of OSM building data (Biljecki & Ang 2020; Orden et al., 2020; Zhou et al., 2020), we have used the Global Human Settlement Layer (GHSL) to estimate completeness of the entire dataset. The remote sensing dataset is distributed onto a grid and in each tile of the grid, the built area of GHSL is compared to the total area of OSM building footprints. The computed ratio is measured against a completeness threshold that is calibrated using areas that were manually assessed.Using information derived from remote sensing datasets can be problematic: GHSL does not only measure building footprints: it includes any human-built structures, including infrastructure and industrial areas. Next to that, due to circumstances like imperfect input data or failing algorithms, the dataset is not of the same quality as the crowd-sourced data in OSM in areas that are complete. False positives (i.e. rocky coasts) and false negatives (i.e. buildings missing in mountainous areas) exist in automatically generated data.Even with these limitations, a comprehensive global completeness assessment is created. The assessment should not be used as ground truth, but rather as reflection on the OSM building dataset as is and as a guideline for priorities for the future. Statistics on regional completeness can be created and the quality of GHSL could be assessed on countries that are considered to be complete, such as France or the Netherlands.
Review of the usage of LUCAS soil data for soil modeling and mapping via bibliometric analysis
Authors: Kaya Fuat , Schillaci Calogero , Kaplan Gordana , Başayiğit Levent
Published: February 2023

A centuries-long research area continues to develop on determining diversity in the heterogeneous environment in which the soil is inherently located. As a result of open data sharing, accessible datasets can be easily used by the scientific community and can be of great benefit to the soil science community and policy stakeholders and improve the learning process for early career researchers. Through bibliometric analysis, this study aims to evaluate the scientific outputs obtained from Web of Science databases produced using the Land Use and Coverage Area frame Survey (LUCAS) soil module dataset between 2000 and 2022. A search was made using the words “LUCAS”, “Soil”, and “European” in the title/abstract/keywords field, and over 100 studies have been found and evaluated. Preliminary results showed that the dataset had been used with interest in the scientific community since the first open access date of 2013 in around 100 peer-review papers. LUCAS has been expanding over the years, and international integration has increased. As a result of bibliometric analysis, many colleagues produced scientific outputs using the LUCAS datasets. Review analysis provides insights into the future use of LUCAS, an open-access dataset, in the scientific community. Results enable academics in this field to give references and quick access to regional soil data information on the principal physical, chemical and selected biological properties.
Improving image-based tracking of slow-moving landslides with optical PlanetScope data: A case study from the Central Andes
Authors: Mueting Ariane , Bookhagen Bodo
Published: February 2023

Optical image offset tracking is a commonly used technique for mapping surface displacements caused by landslides, glaciers, and earthquakes in planar direction. With its daily temporal and high spatial resolution of 3 m, the PlanetScope cubesat constellation provides an excellent data set for studying dynamic surface changes. However, the limited relative geolocation accuracy among PlanetScope scenes with ~10 m RMSE for the PlanetScope SuperDove constellation poses a problem for the identification of slow-moving targets whose annual displacement rates remain well below this value. In this study, we have used PlanetScope data to measure surface displacement over a slow-moving landslide with velocities between 1 and 6 m/yr in the NW Argentine Andes through image cross-correlation techniques. In this steep, rugged environment, not only the misalignment from scene to scene, but also topography-related artifacts and the changing terrain over time, are sources of error. We present several correction steps to improve coregistration accuracy between PlanetScope scenes that lower the relative geolocation accuracy between selected image pairs into the subpixel range. Through an improved scene-to-scene alignment we can better distinguish displacement signal from noise and thus obtain a better understanding of the dynamics of this slow-moving landslide and its driving factors.
Drivers of spatial variability of soil respiration along altitudinal gradient in Northwest Caucasus Mountains
Authors: Gavrichkova Olga , Sushko Sofia , Ovsepyan Lilit , Yevdokimov Ilya , Komarova Alexandra , Zhuravleva Anna , Blagodatsky Sergey , Ivashchenko Kristina
Published: February 2023

Mountains occupy almost a quarter of the land area and store significant pools of soil organic matter (SOM), which is a potential source of atmospheric CO2 under warming climate. However, carbon fluxes in mountain areas with high environmental heterogeneity remain poorly understood, in particular regarding the spatial variability of soil respiration (RS). The study was conducted on the northeastern slope of the Northwest Caucasus Mountains (1260-2480 m a.s.l.; Russia) that crossed five vegetation belts (i.e., mixed, fir and deciduous forests, subalpine and alpine meadows). RS was measured simultaneously (at 10 a.m. on 11 August 2018) across five vegetation belts (at 12 randomly distributed points per belt; totally n = 60) using the closed static chamber technique. As potential drivers of RS spatial variability, soil physico-chemical (temperature, moisture, total and dissolved C and N contents, C:N ratio, pH), soil microbial (microbial biomass C content, basal respiration, enzymatic activities: β-glucosidase, chitinase and leucine aminopeptidase) and vegetation properties (grasses projective cover, its species richness, Shannon-Wiener diversity index, abundance of graminoids and forbs) were assessed. The RS rate ranged from 1.3-12.7 µmol CO2 m-1 s-1, with average values of 3.7 and 7.3 µmol CO2 m-1 s-1 for forests and grasslands respectively. Stepwise regression and subsequent path analysis showed that key driver of RS spatial variability in forests was temperature-sensitive soil chitinase activity (explained variance 50%), while in grasslands it was graminoid abundance (explained variance 27%). The forest soils are mostly limited in N, therefore RS variability depends largely on SOM-derived CO2 sources, i.e. activity of the N-acquiring enzyme. In the grasslands, extensive network of fine roots and the associated considerable contribution of root-derived respiration to Rs, makes the flux more sensitive to vegetation composition and associated phenology and C allocation patterns. Thus, soil N availability and differences in plant cover play a crucial role in regulation of RS spatial patterns in mountains ecosystems.This study was financially supported by Russian Science Foundation, No 22-74-10124.
Measuring of water concentration in rock and soil with muon radiography
Authors: Borozdin Konstantin , Botto Tancredi , De Beer Nicolás , Repenning Ricardo , Rocha Claudio
Published: February 2023

Dry rock and soil have the capability to absorb and contain water because of their porosity. Measuring water concentration in different materials is important for many applications. For example, in heap leaching the leaching liquid distribution directly affects the metal recovery. The water concentration is the key parameter affecting the slope stability, and its measurement is therefore of a great importance for landslide prevention and tailing dams safety. Measurement of this parameter is however a significant challenge, and is done mostly by measuring rainfall in the field and/or analyzing soil samples in the laboratory. These measurements are model-dependent and require significant extrapolation of the results. A direct measurement of the water concentration in-situ is offered by muon radiography - through measuring density distribution based on cosmic-ray muon flux monitoring. By measuring the flux of muons from different directions we can reconstruct density maps of any object they traverse, including large volumes of rock. By monitoring the muon flux, our sensors are sensitive to the density changes in any material above it.  From these density changes we can infer the amount of water contained within the rock or soil.         We performed the first in-situ, fully volumetric monitoring of the water concentration in an active leaching heap in Chile.  Here we discuss the results of these pioneering measurements and the potential for muon imaging of the water concentration for different applications.
Tropical leaf phenology characterization by using an ecologically-constrained deep learning model with PlanetScope satellites
Authors: Song Guangqin , Wang Jing , Liddell Michael , Morellato Patricia , Lee Calvin K.F. , Yang Dedi , Alberton Bruna , Detto Matteo , Ma Xuanlong , Zhao Yingyi , Yeung Henry C.H. , Zhang Hongsheng , Ng Michael , Nelson Bruce W. , Huete Alfredo , Wu Jin
Published: February 2023

Tropical leaf phenology signals leaf-on/off status and exhibits strong variability from individual tree crowns to forest ecosystems, which importantly regulates carbon and water fluxes. The availability of daily PlanetScope data with high spatial resolution offers a new chance to monitor phenology variability at both the fine scale and the ecosystem scale across pan-tropics. However, a scalable method for tropical leaf phenology monitoring from PlanetScope with clear biophysical meaning still needs to be developed. To advance tropical leaf phenology monitoring, we developed an index-guided, ecologically constrained autoencoder (IG-ECAE) method to automatically generate a deciduousness metric (percentage of upper tree canopies with leaf-off status within an image pixel) from PlanetScope. The IG-ECAE includes three steps: (1) extracting the initial reflectance spectra of leafy/leafless canopies based on their spectral indices characteristics; (2) training an autoencoder deep learning method with the guidance of derived reflectance spectra and additional ecological constraints to refine the reflectance spectra; and (3) estimating the relative abundance of leafless canopies (or deciduousness) per PlanetScope image pixel with the integration of refined spectra reflectance and linear spectral unmixing method. To test the IG-ECAE method, we compared the PlanetScope-derived deciduousness to the corresponding measures derived from WorldView-2 (n = 9 sites) and local phenocams (n = 9 sites) at 16 tropical forest sites spanning multiple continents and a large precipitation gradient (1470-2819 mm year-1). Our results show that PlanetScope-derived deciduousness agrees: 1) with WorldView-2-derived deciduousness at the patch level (90 m × 90 m) with r2 = 0.89 across all sites; and 2) with phenocam-derived deciduousness to quantify ecosystem-scale seasonality with r2 ranging from 0.62 to 0.96. These results demonstrate that IG-ECAE can accurately characterize the wide variability in deciduousness across scales from pixels to forest ecosystems, and from a single date to the entire annual cycle, indicating the feasibility of tracking the large-scale phenological patterns and responses of tropical forests to climate change with high-resolution satellites.
Comparing imaging processing techniques with physical based inverse radiative transfer models for methane and carbon dioxide point emissions
Authors: Jandl Ida , Scheidweiler Leon , Landgraf Jochen , Maasakkers Joannes D. , Butz André
Published: February 2023

Satellite remote sensing techniques offer the possibility of an independent global monitoring of carbon dioxide (CO2) and methane (CH4) emissions. Recently, point sources such as oil and gas facilities and power plants, which emit a high concentration of greenhouse gases (GHG) locally, have received particular attention. Therefore, present and upcoming satellite missions focus on collecting GHG concentration images with a high spatial resolution. The PRISMA (PRecursore IperSpettrale della Missione Applicativais) spaceborne imaging spectrometer is an Italian satellite which has been launched on March 22, 2019. It is the first satellite which provides open access hyperspectral images of backscattered sunlight with a spatial resolution of 30x30 meter and a spectral resolution of around 11nm. The measured absorption spectra in the shortwave infrared range cover strong CO2 and CH4absorption bands. Various methods can be used to retrieve 2-dimensional CO2 and CH4fields above localized GHG sources. Here, we compare data-driven and physics-based retrieval methods in application to PRISMA measurements above localized GHG sources such as oil and gas production facilities in Turkmenistan for CH4 and coal-fired power plants for CO2. The data-driven methods are variants of the matched filter technique while the physics-based methods built on spectroscopic radiative transfer modeling. While matched filter techniques use the spatial covariance of the observed scene, traditional physics-based retrievals operate on individual spectra without considering the two-dimensional scene. For a few cases, we examine the differences between both methods and conclude on strengths and weaknesses.
Dense water formation in the Eastern Mediterranean under global warming scenario
Authors: Parras Berrocal Iván Manuel , Vázquez Rubén , Cabos William , Sein Dmitry V. , Álvarez Oscar , Bruno Miguel , Izquierdo Alfredo
Published: February 2023

Dense water formation in the Eastern Mediterranean (EMed) is essential in sustaining the Mediterranean overturning circulation. Changes in the sources of dense water in the EMed point to changes in the circulation and the water properties of the Mediterranean Sea. Here we examine with a regional climate system model the changes in the dense water formation in the EMed through the twenty-first century under the RCP8.5 emission scenario. Our results show a shift in the dominant source of Eastern Mediterranean Deep Water (EMDW) from the Adriatic Sea to the Aegean Sea at the first half of twenty-first century. The projected dense water formation reduces by 75% for the Adriatic Sea, 84% for the Aegean Sea and 83% for the Levantine Sea by the end of the century. The reduction in the intensity of deep water formation is related to hydrographic changes of surface and intermediate water, that strengthen the vertical stratification hampering the vertical mixing and thus the convection. Those changes have an impact on the water that flows through the Sicilian Strait to the Western Mediterranean and therefore on the whole Mediterranean system.