bluuebunny/crossref_metadata_2025 huggingface dataset:
How small can ground movements be to be detectable with GNSS?
Authors: Hohensinn Roland , Ruttner Pia , Soja Benedikt , Rothacher Markus
Published: March 2021

High-precision GNSS (Global Navigation Satellite System) positioning can reach an accuracy at the millimeter level, and by collecting these data over years, very small ground movements can be resolved. These data can be used to study geodynamics, like continental drifts, tidal- and non-tidal loading effects, or earthquakes, for example. Here we focus on the sensitivity of GNSS for resolving these different types of movements. We derive minimal detectable displacements for linear drift rates, annual- and semiannual periodic motions, and offsets – these are main parameters of the so-called standard linear trajectory model for GNSS station motions. For our analysis, our data comes from several hundreds of permanent GNSS stations across Europe– the GNSS stations’ coordinates are obtained at a daily sampling rate, with almost 25 years of data available for some stations. Based on cleaned residual GNSS time series we calibrate a “power-law plus white noise” stochastic model for each station. Together with the functional trajectory model we compute the formal errors of the movement parameters based on a least-squares adjustment. Based on these errors we then introduce the statistics to derive minimum detectable displacements for the movement parameters.

Our analysis shows that the minimum detectable trends can be as low as few tenth of millimeters per year. The minimum detectable amplitudes at the annual and semiannual periods are at the millimeter level or lower, and the detectable offset is few millimeters on average, too. As expected, the minimum detectable displacements depend strongly on the length of the datasets and on the noise characteristics. Another important parameter is the number of discontinuities and offsets for each station – it impacts the minimum detectable trend. We conclude that such an analysis can be very useful for sensitivity studies in climate change monitoring. Furthermore, the methodology cannot only be applied in the field of GNSS time series analysis, but also to any other time series data in geosciences.
Evolution of bubble statistics in intermediate water due to phase shifted breaking wave groups
Authors: Chasapis Konstantinos , Buldakov Eugeny , Czerski Helen
Published: March 2021

The bubbles generated by breaking waves in the open ocean are an important feature of the ocean surface. They affect optical and acoustical properties of the top few meters of the ocean, influence surfactant scavenging, aerosol production and air-sea gas transfer. Short-lived larger bubbles which re-surface and burst dominate the transfer of less soluble gases such as carbon dioxide. A single wave crest approaching breaking deforms rapidly and in a storm sea the most common breaker is the spilling type. Detailed observations in space and time connecting the shape of the spilling breaker to subsequent bubble populations are limited, and the effect on the bubble penetration depth and residence time underwater is particularly important. In this study, we carried out a series of experiments to track the formation and evolution of large bubbles for different local crest geometries.

A breaking wave in a wave flume was generated with dispersive focusing of a wave group. The group has a pre-defined amplitude spectrum. Running experiments with different phase shifts of the same amplitude spectrum showed that when a peak-focussed wave (zero phase shift) breaks, then wave groups with other added phase shifts break as well. To investigate possible differences in the deformation of those breakers a laser imaging technique was used. An algorithm identified the 2D shape of the breaker in successive images. It also separated the crests from bulges based on geometric criteria. We showed that, despite wave groups having same spectra, the extracted bulges differed locally in shape, volume and velocity for each phase shift at the location of breaking. Therefore, breakers ranging from the more traditional spilling type, which has a bulge that collapses on the front face of the wave, to the micro-plunging type, which has a pronounced overturning tip, were observed depending on the phase shift. 

The evolution of bubbles for each phase shifted bulge was captured by a high speed camera and measured by a feature extraction algorithm. We generally found that spilling bulges created fewer bubbles in total than micro-plungers. They also created fewer larger bubbles, i.e. with radius r>1 mm, at all measured flume areas. In contrast, micro-plungers that trap air within a small cavity as they break had less steep size distributions for r>1 mm. The maximum volume of air per radius showed a gradual shift from r>1 mm to r=1 mm moving away from the breaking location for all breakers. It is interesting, finally, that the maximum volume per radius did not shift to smaller radii as time passes. This is an indication that the largest bubbles, i.e. r>4 mm, rise to the surface and burst instead of splitting into smaller ones, irrespectively of the local breaker properties. 
The role of atmospheric dynamics in extreme wildfire activity in northeastern Siberia
Authors: Scholten Rebecca , Dim Coumou , Fei Luo , Veraverbeke Sander
Published: March 2021

In the summer of 2020, extreme fires have raged in northeastern Siberia, many of them within the Arctic Circle burning in ecotonal larch forest and tundra ecosystems. This unprecedented increase in fire activity within the Arctic Circle has been linked to record-high temperatures measured in the region, as well as to high lightning activity.

In mid-latitudes, the pronounced and long-lasting heatwaves of the last decade have been linked to amplified Rossby waves connected with weak atmospheric circulation. These amplified waves tend to phase-lock in preferred positions and thereby lead to more persistent summer weather. Linkages between atmospheric teleconnections and boreal wildfires exist for some regions, yet the influence of wave dynamics on arctic-boreal wildfires is unknown. We explored relationships between wave dynamics, heatwaves, and the unprecedented fire activity in Siberia in 2020 to assess whether the recent surge in arctic-boreal fires in Siberia is driven by large-scale atmospheric dynamics.

We determined wave amplitudes as phase positions by applying fast Fourier transformation on weekly averaged mid- to high-latitudinal mean meridional wind velocities at the 250 mb level from ERA5 reanalysis data. Gridded percentage area burned between 2001 and 2020 was derived from the Moderate Resolution Imaging Spectrometer (MODIS) Burned Area product (MCD64A1). We then quantified the importance of Rossby wave patterns on fire activity clustered by latitude in eastern Siberia.
Investors’ Climate Sentiment and Financial Markets
Authors: Santi Caterina
Published: March 2021

We propose a measure of investors’ climate sentiment by performing sentiment analysis on StockTwits posts on climate change and global warming. We find that investors’ climate sentiment generates a mispricing in the Emission-minus-Clean (EMC) portfolio (Choi et al., 2020), the portfolio that invests in emission stocks and goes short on clean stocks. Specifically, when investors share a positive attitude towards climate change, they tend to overvalue the negative externalities produced by emission stocks. Moreover, we show that carbon prices are a successful incentive to reduce CO2 emissions. Finally, our model can predict the price of the EMC portfolio also for long-term horizons.
Paleozoic subduction of the Mongol-Okhotsk oceanic plate: insight from the petrogenesis of Ordovician to Devonian granitic plutons in the Hangay Range, central Mongolia
Authors: Ling jiaqi , Li pengfei
Published: March 2021

Email: pengfeili@gig.ac.cn; pengfeili2013@gmail.com

 

The pre-Mesozoic subduction history of the Mongol-Okhotsk oceanic plate has been poorly understood. Here we conducted geochronological and geochemical studies on four granitic plutons in the westernmost Mongol-Okhotsk Orogen (Hangay Range), with an aim to understand their petrogenesis and role in the Paleozoic tectonic evolution of the Mongol-Okhotsk Orogen. Our geochronological results constrain four granitic plutons to be emplaced from middle Ordovician to early Devonian. Geochemically, the Ordovician pluton belongs to A2-type granites, and three Silurian to Devonian plutons show the characteristics of I-type granites. These granitic plutons were probably generated by partial melting of basaltic rocks in the lower crust given the high contents of Na2O and K2O. The negative εNd(t) values (-4.7 to -0.9) and variable εHf(t) values (-2.6 to +6.1) for the four granitic plutons suggest that ancient basement materials were possibly involved in the magma source. We further investigate the geodynamic origin of these plutons in the context of the Paleozoic tectonics of the Mongol-Okhotsk Orogen, and we conclude that they were probably formed in response to the Ordovician to Devonian subduction of the Mongol-Okhotsk oceanic plate.
Thermospheric Neutral Winds: A Driver of the Earth’s Inner Radiation Belt to Be Reckoned With
Authors: Lejosne Solène , Maruyama Naomi , Selesnick Richard S. , Fedrizzi Mariangel
Published: March 2021

Neutral winds have long been viewed as a driver of Jupiter’s radiation belts. On the other hand, the impact of thermospheric neutral winds in driving plasma dynamics in the Earth’s inner magnetosphere is yet to be quantified. We now have the appropriate combination of data and physics-based model to address this fundamental science question.

In this work, we revisit the local time asymmetry of the equatorial electron intensity observed in the innermost radiation belt (L=1.30). We combine in-situ field and particle observations, together with a physics-based coupled model, RCM-CTIPe, to determine whether the dynamo electric fields produced by tidal motion of upper atmospheric winds flowing across the Earth’s magnetic field lines are the main drivers of the drift-shell distortion observed in the Earth’s inner radiation belt.

Our results provide a first quantification of the contribution of the neutral wind in transporting the trapped energetic particles of the Earth’s inner radiation belt.
National Geoinformation Center and its Role for Communication of Natural Hazards and Risks to the General Public in Bulgaria
Authors: Trifonova Petya , Miloshev Nikolay , Georgiev Ivan
Published: March 2021

The National Geoinformation Center (NGIC) is a Bulgarian scientific infrastructure whose main goal is integration of primary data concerning the geo-environment and providing data products and services to the scientific community, responsible institutions and general public.

The first and main module of this newly established infrastructure is dedicated to monitoring and study of the Earth and outer space. The technical capacity of the involved partners include unique equipment such as seismic, accelerometric, geodetic, meteorological and oceanographic stations, and scientific instruments in several laboratories (geotechnical, paleomagnetic, chemical, biological and computer). Thus, the partners in the consortium provide monitoring of a series of phenomena affecting the solid Earth (earthquakes, rock falls and landslides, soils), air (pollution, UV radiation, magnetic storms) and water (river, ground and sea). And of course are responsible for information dissemination, collaboration with policy makers, responding to media and last but not least communication to general public.

We have chosen three main channels to deliver our data and knowledge to the society. The first one uses the means of internet platforms– web page and social channels where NGIC provide real time data about more than 10 phenomena (earthquakes, magnetic storms, UV radiation, air pollution, etc.). The second channel is dedicated to elaboration of educational programs for students in different age categories. They rely on materials illustrated with many pictures, videos and examples that would be easily perceived by modern children. Resources are designed to be easily adapted to different types of learning – on spot, face-to-face in class or electronic. The third communication channel uses well-illustrated popular science materials that are suitable for publication on various platforms - websites, magazines, specialized publications and any other media. Interest in them increases significantly in cases where there is an event representing a natural hazard or the risk of such a phenomenon increases.

Using the described ways of communication, our goal is to reach as much as possible users in the society. The experience gained shows that in addition to the requirements for the information (to be timely, high-quality and reliable), it is necessary to pay close attention to the way of materials presentation and their graphical layout.

 
Reprocessing of the Hartebeesthoek 2014 co-location survey
Authors: Collilieux Xavier , Muller Jean-Michael , Pesce Damien
Published: March 2021

A local tie survey was carried out at Hartebeesthoek observatory (South Africa) in February 2014 by surveyors from Rural Development & Land Reform, University of KwaZulu-Natal, NASA and IGN. Hartebeesthoek observatory is one of the few sites in the world which currently hosts instruments from the four space geodesy techniques, namely DORIS, GNSS, SLR and VLBI. A first adjustment of the survey observations was carried out in 2014 and the tie vectors between instrument reference points were published.

As the precision of the VLBI axis offsets was requested by the International VLBI Service and a new version of the IGN adjustment software COMP3D was released, it was decided to reprocess the survey data of the main Hartebeesthoek observatory sub-site HartRAO. Indeed, the new software package allows processing in one step complex survey data, specifically in case of indirect determination of VLBI and SLR telescope reference points. The new processing strategy will be described and the tie vectors compared with 2014 results.
Spatial distribution of cereal yields related to the application of soil-improving cropping systems (SICS)
Authors: Lipiec Jerzy , Usowicz Boguslaw
Published: March 2021

Research indicates that spatial differentiation of crop yields and soil properties are largely influenced by agricultural practices and the nature of the soil itself. The aim of this study was to examine the spatial relationship between cereal (wheat and oats ) yields and soil properties related to the application of soil-improving cropping systems (SICS). Four-year experiment (2017-2020) was carried out on low productive sandy soil with application of following SICS: S1 – control; S2 – liming; S3 – green manure/cover crops including lupine, phacelia, serradella; S4 – manure and S5 – manure, liming and cover crops together. Effect of the SICS was evaluated using classical statistics, Bland-Altman analysis and geostatistical methods. Mathematical functions, fitted to the experimental cross- and semivariograms were used for mapping the yields (grain and straw) by ordinary cokriging. The grain yields in years with normal rainfall increased by 2% for S2, 10% for S3, 46% for S4, 47% for S5 compared to control (S1) 2789 kg/ha and in dry years were lower (respectively for S2-S5 by 16.3, 10.6, 2.8, 9.9% compared to control 1567 kg/ha. The range of spatial dependence for the yields in direct semi-variograms varied was 50–100 m and > 100 m in cross-semivariograms using textural fractions as secondary variables. The spatial relationships were stronger between yield and soil texture and properties were much stronger with texture and cation exchange capacity than with pH and organic carbon content. Using cokriging for interpolation (mapping) allowed the delineation of zones of lower and higher cereal yields including areas of the SICS application. Higher cereal yield and lower spatial variability in the areas of SICS compared to control soil were observed in the years with normal rainfall. Analysis of the Bland-Altman including limits of agreement enabled to quantify the effect of particular SICS on cereal yield vs. control reference. Different effect of particular SICS on the cereal yield was observed in the years with scarce and good rainfall amount and distribution during growing season. The greatest variation of the cereal yield was observed in manure amended soil (S4) and it was lower and similar in the areas of remaining SICS (S2-S5). The results will help to to select most effective SICS for localized improving crop productivity and adaptation to global warming.

Acknowledgements.The study was funded by HORIZON 2020, European Commission, Programme H2020-SFS-2015-2: SoilCare for profitable and sustainable crop production in Europe, project No. 677407 (SoilCare, 2016-2021).
Evolutionary development and volume balance calculations of the Ana Slide in the Eivissa Channel, Western Mediterranean
Authors: Sager Thore F. , Urlaub Morelia , Kaminski Pauline , Lastras Galderic , Canals Miquel , Berndt Christian
Published: March 2021

Submarine landslides are widespread phenomena on continental slopes and act as prime sediment transport processes between shallow and deep marine regions. In addition, they pose significant risk to coastal communities worldwide. Within this study, we focus on the Ana Slide, a relatively small landslide with areal extent of 4.7 km2 located at water depth between 635 – 905 m on the eastern slopes of the Eivissa Channel, western Mediterranean. Predominant sediment types are high-water content, carbonate-dominated hemipelagic deposits susceptible to high pore pressures and liquefaction. The Ana Slide is completely covered by very-high resolution bathymetric and 3D seismic data and additional legacy data, what allows us to perform detailed kinematic analysis of the landslide evolutionary development.
The Ana Slide is characterised by three landslide domains: the 1) evacuational or headwall domain, 2) translational domain, and 3) accumulational or toe domain. While the headwall domain demonstrates classic features of material evacuation and poses as the exclusive source of material within the landslide process, the translational domain is characterised by extensive in-situ remnant blocks which were unaffected during failure. Instead, landslide material from the evacuational domain moved up and over the translational domain. The toe domain exhibits extensive chaotic seismic facies with compressional ridges throughout the deposit and imprinted onto the seafloor. 
Even though the toe domain is characterised by extensive chaotic seismic facies, its volume differs significantly from the volume of the evacuated material. Thus, we conclude that the chaotic seismic facies does not represent landslide material. Instead, the in-situ sediment underwent a range of soft-sediment deformation processes. We propose two mechanisms responsible for this deformation: loading- and shearing-induced soft-sediment deformation resulting from rapid deposition of overburden material. Under consideration of the likely elevated pore pressure and liquefaction potential of deposits, these mechanisms lead to the destruction and disturbance of internal reflections.
Our analysis demonstrates the difficulties in distinguishing between actually failed landslide material and deformed but not translated sediment, which may well lead to erroneous landslide volume estimations. Our new model of the evolutionary development of the Ana Slide may well hold for many other submarine landslides globally, the volumes of which could be significantly overestimated.
Insights into the ocean’s biological carbon pump: What makes marine snow falling into the deep ocean?
Authors: Le Moigne Frederic
Published: March 2021

The oceanic biological carbon pump (BCP) regulates the Earth carbon cycle by transporting part of the photosynthetically fixed CO2 into the deep ocean. Suppressing this mechanism would result in an important increase of atmospheric CO2 level. The BCP occurs mainly in the form of organic carbon particles (POC) sinking out the surface ocean. Various types of particles are produced in surface ocean. They all differ in production, sinking and decomposition rates, vertically and horizontally. The amount of POC transported to depths via these various export pathways as well as their decomposition pathways all have different ecological origins and therefore may response differently to climate change. Here I will briefly review some of the processes driving both particle export out of the euphotic zone (0-100m) as well as particles transport within the mesopelagic zone (100-1000m). In the early 2000s, strong correlations between POC and mineral (calcite an opal) fluxes observed in the deep ocean have inspired the inclusion of “ballast effect” parameterizations in carbon cycle models. These relationships were first considered as being universal. However global analysis of POC and mineral ballast fluxes showed that mineral ballasting is important in regions like the high-latitude North Atlantic but that in most places (some of which efficiently exporting) the unballasted fraction often dominates the export flux. In such regions, we later showed that zooplankton-mediated export (presence of faecal pellets) and surface microbial abundance were important drivers of the efficiency of particles export. Similar trends were found globally by including bacteria and zooplankton abundances to a global reanalysis of the global variations of the POC export efficiency. This implies that the whole ecosystem structure from bacteria to fishes, rather than just the phytoplankton community, is important in setting the strength of the biological carbon pump. Further down in the water column (mesopelagic zone), processes impacting the transport of particles are less clear. Sinking particles experience a number of biotic and abiotic transformations during their descent. These includes solubilization, remineralisation, fragmentation, ingestion/active transport, breakdown among others. While some potential factors such as O2 concentration and temperature have been proposed as powerful controls, global evidences are often inconsistent. In the award talk, I will review current challenges related to the role of particles consumption by zooplankton and fishes as well as the role of particles attached prokaryotes (bacteria and archaea) in setting the efficiency of the carbon transport in the mesopelagic zone.
The relevance of groundwater-lake interactions for the rapid eutrophication of Lake Stechlin
Authors: Lewandowski Jörg , Mehler Franziska , Bhardwaj Himanshu , Jäger Anna
Published: March 2021

Until recently, Lake Stechlin was one of the few oligotrophic lakes in North-Eastern Germany. Lake Stechlin is located in a nature reserve and its catchment is nearly completely forested, there is no agriculture and only one small settlement. About 10 years ago there were the first indications in the lake’s hypolimnion for changes of the trophy. In the last 3 years the lake is experiencing a rapid eutrophication and phosphorus (P) concentrations quadrupled compared to the concentrations 10 years ago. It is generally agreed that the origin of this P is internal P cycling which is a self-reinforcing process. However, the trigger that started the intense internal P cycling is still unknown. There are several different hypotheses and we focused on investigating the role of groundwater for the eutrophication of Lake Stechlin. Groundwater is a crucial component of the water balance of Lake Stechlin because there are basically no surface inflows and outflows, i.e. besides precipitation and evaporation, both lacustrine groundwater discharge and infiltration of lake water into the aquifer are the only other relevant terms of the water balance. Anthropogenic and climate change-induced alterations in groundwater inflow and outflow might have triggered the rapid eutrophication by different processes and we present a conceptual model of the involved processes. Main findings are (1) At a few locations we measured P concentration in the aquifer which were up to two orders of magnitude above the P concentrations of the lake water. (2) Due to several years of low precipitation in a row, the volume of lacustrine groundwater discharge decreased and with that the input of important P binding agents decreased, thus influencing the lake's internal P cycling. (3) Warmer average annual temperatures increase evaporation and simultaneously lead to a concentration of phosphorus in the lake. Local reversals of groundwater flow directions could also prevent lake water and with it P from leaving the lake. Thus, groundwater might be an important factor for the degradation of Lake Stechlin.
Recent reversal of mean wind speed and gusts across the Iberian Peninsula and its relationship with modes of climate variability, 1961-2019
Authors: Utrabo-Carazo Eduardo , Azorin-Molina Cesar , Serrano Encarna , Aguilar Enric , Brunet Manola
Published: March 2021

In a context of climate change, near-surface wind speed (SWS) has received less attention than other variables such as air temperature or precipitation, despite its undeniable environmental and socio-economic impacts. Studies suggest a generalized decrease of SWS in continental surfaces located in the middle latitudes from 1979 to 2010, the so-called stilling phenomenon, and an increase in it thereafter, which has been termed reversal or recovery phenomenon. Recent studies indicate that multidecade oscillations produced by the internal variability of the climate system are responsible for both phenomena. The aim of this work is to advance in the evaluation of the multidecadal variability and causes of the stilling and reversal in the observed SWS, covering the complete 2010s decade and focusing on the Iberian Peninsula region (IP). More specifically, the particular objectives of this study are: (i) to determine for the first time the occurrence of the reversal phenomenon in the IP over the last decade(s), identifying its onset year and its magnitude; (ii) to deepen into the relation between atmospheric teleconnection indices and observed trends in SWS; and (iii) to link atmospheric circulation changes to observed SWS variability. For that purpose, homogenized series of mean wind speed and gusts will be used, as well as data from the ERA5 reanalysis (European Centre for Medium-Range Weather Forecasting). Three SWS parameters will be analysed: monthly mean SWS anomaly; monthly mean daily peak wind gust (DPWG) anomaly; and number of days in which the value of DPWG exceeds the 90th percentile of the series considered. Trends of these parameters will be calculated, as well as the correlation between them and the modes of variability that govern in the region: North Atlantic Oscillation (NAO), Mediterranean Oscillation (MO) and Western Mediterranean Oscillation. Finally, trends of these modes of variability and of other parameters dependent on atmospheric circulation (e.g., geostrophic wind) will be calculated to try to clarify the drivers of the observed changes in the SWS.
Mid-Pliocene warming: reducing discrepancies between geological archives and climate models in the NE Atlantic and Nordic Seas
Authors: Hall Jonathan , Jones Stephen , Dunkley Jones Tom , Bendle James
Published: March 2021

The mid-Pliocene Warm Period (mPWP) is the most recent time slice (3.264–3.025 Ma) during which average global surface temperatures were 2–3°C warmer than preindustrial conditions, within the range estimated by the Intergovernmental Panel on Climate Change (IPCC) for the end of the 21st Century. Global mPWP sea surface temperature (SST) compilations indicate enhanced warming in the NE Atlantic and Nordic Seas, with anomalies of >6°C based on alkenone methods (Dowsett et al., 2012). However, this warming far exceeds the more conservative SST estimates (a rise of 2−3°C) predicted by the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) reconstructions and leading climate models (including HadCM3). Here, we present new mid-Pliocene alkenone SST records from four regional drilling sites (IODP Site U1308, DSDP Site 552, ODP Site 642 and ODP Site 907) to further examine the magnitude of warming in the NE Atlantic and Nordic Seas, and to evaluate regional discrepancies between proxy and model SST estimates. We demonstrate mid-Pliocene SSTs peaked up to 21.5°C and 19.7°C in the NE Atlantic and Nordic Seas, respectively, consistent with existing studies (Robinson et al., 2008; Robinson, 2009). However, we reveal the majority of these SST estimates are derived from GC injections of relatively low total alkenone concentrations (<50 ng/µl), which are susceptible to warming biases caused by chromatographic irreversible adsorption (Grimalt et al., 2001). We subsequently filtered and applied a mathematical correction to our new data to rectify for these warming biases, which results in a reduction in mPWP SSTs, by up to 3.2°C, across all four sites. The corrected (and cooler) alkenone SST records indicate the magnitude of warming in the NE Atlantic and Nordic Seas may be significantly less than previously thought, helping to reduce and explain regional discrepancies between proxy- and model-based SST reconstructions.
A licensing system for planetary geospatial data for the GMAP project
Authors: Frigeri Alessandro , Rossi Angelo Pio , Nass Andrea , Massironi Matteo
Published: March 2021

The Geologic Mapping of Planetary Bodies (GMAP) project Integrates partners and outputs from two projects previously funded by the EU through Horizon 2020 (UPWARDS and PLANMAP) to deliver tools and services for geological mapping of any Solar System body.  Started in 2020, GMAP is developing an infrastructure to support future European missions in developing orbital acquisition strategies, rover deployment and traverses, and human exploration programs.  Part of GMAP deals with the study of current procedures for publishing planetary maps, and the development of new ones.   Since the Apollo era, geologic maps of the Moon and bodies of the solar system have been produced and disseminated by the United Stated Geologic Survey, Astrogeology Program, funded by NASA.  Being both USGS and NASA governmental organization of the same country, the coordination and the production of planetary maps followed a straightforward development from the beginning to the digital-era.  In their digital form, the US maps have been made available under the public domain.
At the international level, every country has its own space agency or office but no public domain planetary maps have been systematically made available yet in re-usable formats outside the US. In Europe, space programs can be either promoted by European Space Agency or by any one of the participating states' space agencies, which is not necessarily an EU member. This is not ideal for a coordinated work for geoscientific mapping or dissemination of unified planetary mapping products.
Within GMAP we are surveying existing licensing models, looking for a licensing system that guarantees dissemination and the re-use of planetary mapping, the maximum compatibility with the existing dataset and protects original creator rights.   We will report the status of our study and plans for the future.
Atmospheric and oceanic drivers of regional Arctic winter sea-ice variability in present and future climates
Authors: Dörr Jakob , Årthun Marius , Eldevik Tor , Madonna Erica
Published: March 2021

The recent retreat of Arctic sea ice area is overlaid by strong internal variability on all timescales. In winter, sea ice retreat and variability are currently dominated by the Barents Sea, primarily driven by variable ocean heat transport from the Atlantic. Climate models from the latest intercomparison project CMIP6 project that the future loss of winter Arctic sea ice spreads throughout the Arctic Ocean and, hence, that other regions of the Arctic Ocean will see increased sea-ice variability. It is, however, not known how the influence of ocean heat transport will change, and to what extent and in which regions other drivers, such as atmospheric circulation or river runoff into the Arctic Ocean, will become important. Using a combination of observations and simulations from the Community Earth System Model Large Ensemble (CESM-LE), we analyze and contrast the present and future regional drivers of the variability of the winter Arctic sea ice cover. We find that for the recent past, both observations and CESM-LE show that sea ice variability in the Atlantic and Pacific sector of the Arctic Ocean is influenced by ocean heat transport through the Barents Sea and Bering Strait, respectively. The two dominant modes of large-scale atmospheric variability – the Arctic Oscillation and the Pacific North American pattern – are only weakly related to recent regional sea ice variability. However, atmospheric circulation anomalies associated with regional sea ice variability show distinct patterns for the Atlantic and Pacific sectors consistent with heat and humidity transport from lower latitudes. In the future, under a high emission scenario, CESM-LE projects a gradual expansion of the footprint of the Pacific and Atlantic inflows, covering the whole Arctic Ocean by 2050-2079. This study highlights the combined importance of future Atlantification and Pacification of the Arctic Ocean and improves our understanding of internal climate variability which essential in order to predict future sea ice changes under anthropogenic warming.   

 
Rapid changes in primary productivity and oxygen depletion during sapropel deposition: implications for reconstructing seawater oxygen levels
Authors: Monedero-Contreras Ricardo D. , Martinez-Ruiz Francisca , Rodríguez-Tovar Francisco J. , Gallego-Torres David , de Lange Gert
Published: March 2021

The deposition of Organic-Rich Layers (ORLs) and sapropels in the Mediterranean Sea basins represents an exceptional record of severe changes in oxygenation over the recent geological past. Such changes are also associated to rapid productivity oscillations that involved a major increase in export fluxes of organic carbon. These episodes of enhanced production and preservation of organic matter can be used as a natural archive for studying oxygen fluctuations and deoxygenation events, and a better comprehension of the causes and consequences of past events will provide valuable information to further understand oxygen level variations in future scenarios. In general, sapropel deposition has been related to increased productivity and sluggish water circulation in response to African monsoon variability. To further understand how such conditions led to bottom water oxygen depletion, a multiproxy approach, including diverse geochemical and ichnological proxies, has been applied. Obtained results have provided new insights into the relationship between productivity and oxygen conditions in the water column and at the sediment-water interface. Sapropels intervals from cores recovered at four ODP Leg 160 sites were selected across an East-West transect of the Eastern Mediterranean basin entailing diverse depths and oceanographic regimes. At these sites, sapropel layers had been well characterized in terms of productivity (i.e. Ba/Al and TOC), and new analyses have been performed to provide additional redox proxies, i.e. degree of pyritization (DOP), trace elements ratios, and enrichment factors (EF) that have allowed a high-resolution reconstruction of bottom-water ventilation. Also, a preliminary ichnological approach is coupled with the geochemical information to assess the response of the macrobenthic trace maker community to the redox changes at the sediment-water interface. Trace metal proxies indicate a significant, though variable, decreasing oxygenation during sapropel deposition, also supported by important pyritization within sapropel layers.
Using a regional version of the AquaCrop model to simulate crop biomass and soil moisture: an evaluation with remote sensing data products
Authors: de Roos Shannon , De Lannoy Gabrielle , Raes Dirk
Published: March 2021

A shift to more sustainable land cultivation practices is necessary to meet the future crop demand, which faces a vastly growing population and changing climatic conditions. To assess which management practices can be effectively applied at a regional scale, good spatial monitoring techniques are required. With a regional version of the AquaCrop model v6.1, we simulate crop biomass production and soil moisture at a 1-km resolution over Europe. Biomass productivity is compared against the Dry Matter Productivity of the Copernicus Global Land Service, derived from optical satellite sensors, while surface moisture content is evaluated with Sentinel-1 and SMAP microwave satellite retrieval products and inter-compared with in situ data. We show that the AquaCrop model can successfully be applied at a relatively fine resolution over a large scale, using global input data.

This research is part of a H2020 project, named SHui. SHui is a collaborative effort between Universities from Europe and China, with the overall aim of managing water scarcity in cropping systems for individuals as well as stakeholder organizations.
Revisiting the crevasse-depth calving law in the presence of melt undercutting
Authors: Slater Donald , Benn Doug , Cowton Tom , Bassis Jeremy , Todd Joe
Published: March 2021

For tidewater glaciers worldwide, calving is a principal mechanism of mass loss. In turn, undercutting of tidewater glacier termini by submarine melting is understood to be a principal driver of calving. Yet, we currently have no practical and widely-accepted parameterisations that can represent the impact of submarine melting on calving in ice sheet models that are used for sea level projection, reducing confidence in their predictions.

The ‘crevasse-depth calving law’ that broadly relates depth-mean stress to a crevasse depth has been very widely used in models of tidewater glaciers, but this law does not fully account for the impact of submarine melt undercutting on the near-terminus stress field, which may be the key link between tidewater glaciers and the ocean. As such, we here work to incorporate the full impact of melt undercutting into a revised crevasse-depth calving law.

We combine elastic beam theory, linear elastic fracture mechanics and Elmer/Ice simulations to study the propagation of surface and basal crevasses near the front of tidewater glaciers in response to melt undercutting. We work to parameterise these results through a simple revision of the existing crevasse-depth calving law. The revised law explicitly accounts for the impact of melt undercutting on crevasses near the terminus, without increasing the computational demand on ice sheet models that might incorporate such a law, representing an important step towards better projection of ice sheet mass loss driven by the ocean.
Global moisture hotspots for terrestrial precipitation: the variabilities and possible linkages to climatic events and human activities
Authors: Cheng Tat Fan , Lu Mengqian , Dai Lun
Published: March 2021

As the world population continues to rise under global warming, it becomes increasingly urgent to understand the climate system and atmospheric water cycle,  which could be beneficial for assessing future freshwater resources and land-use management. Recent endeavors by the regional studies were put to identify the source-receptor network and synoptic-scale moisture transport in major river basins worldwide affected by monsoons. Notably, growing studies suggest the transboundary upwind moisture sources are, in fact, very crucial to the intensity and variability of precipitation in the downwind areas, which arouses the call for international governance over land-use and water management. Recognizing the need for international governance on moisture sources from different regional studies and considering results from many moisture-sink-orientated studies, it, however, remains largely unclear where exactly are the moisture source hotspots that are shared by most countries and societies. Such information would better facilitate the international attention, effort and policymaking to safeguard those influential moisture hotspots. Further, more scientific questions need to be addressed: how these global moisture hotspots vary in time and space for the past few decades, and how would these changes be attributed to the known climate events and even human activities.

To these ends, we utilize a state-of-the-art three-dimensional Lagrangian model, the FLEXible PARTicle dispersion model (FLEXPART), to homogeneously divide the atmosphere into six million parcels with roughly equal masses and simulate their movements from 1971 to 2010. Instead of focusing on a particular sink region, all the moisture released over land is backtracked to construct a map of moisture hotspots throughout seasons. As surprising as it may seem, the results suggest the majority of global moisture source hotspots for land precipitation are also terrestrial, especially those located in the Amazon rainforest, the Congo rainforest, the Ganges river basin, the Mekong river basin and the Yangtze River basin. Most of these hotspots also situate in monsoonal domains where their strengths vary significantly across seasons. Given also significant interannual variabilities and long-term trends in the strength of these globally shared moisture hotspots, we suspect that climatic events, global warming and urbanization processes could be attributable to the changes in the hotspots. Findings from this work would advance our knowledge of the location of global moisture hotspots that are key to the precipitation over land. Understanding the possible linkages between the hotspots’ changes and climatic events and human-related activities could benefit long-term planning of regional and international strategies for securing freshwater resources.
The dependence of the breakup of marine stratocumulus on autoconversion parameterizations
Authors: Liu Zhoukun , Wang Minghuai , Rosenfeld Daniel , Zhu Yannian
Published: March 2021

The marine stratocumulus (MSC) covers extensive regions of the eastern subtropical oceans, and it is an important contributor to the global radiation budget. Accompanied with precipitation, the regime of MSC often transform from closed cells (nearly overcast) to open cells (with cloud fraction ≤ 65%), which results in substantial decrease of cloud radiative effect (CRE). Given the fact that current parameterizations of warm rain formation process differ a lot from each other in climate models and the discrepancy of the precipitation characteristics between observation is usually large, observational constraints on the aerosol-cloud interactions in the transition process is particularly needed at current stage. In this study, the parameterization of autoconversion rate by Khairoutdinov and Kogan (2000) (KK2000 hereafter) embedded in a regional model, the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) is evaluated with the observed cloud and precipitation by satellites in the breakup transition process over the northeast Atlantic. The sensitivity tests show that the cloud properties precipitation characteristics, and CRE during the breakup process depends a lot on the parameters in KK2000, and satellite observations offer efficient constraints on the conventional autoconversion parameterizations.

 

 
Assessing the biogeographical and socio-ecological representativeness of the ILTER site network
Authors: Wohner Christoph , Ohnemus Thomas , Zacharias Steffen , Mollenhauer Hannes , Ellis Erle , Klug Hermann , Shibata Hideaki , Mirtl Michael
Published: March 2021

The challenges posed by climate and land use change are increasingly complex, with rising and accelerating impacts on the global environmental system. Novel environmental and ecosystem research needs to properly interpret system changes and derive management recommendations across scales. This largely depends on advances in the establishment of an internationally harmonised, long-term operating and representative infrastructure for environmental observation. One example for such an infrastructure for environmental observation is the International Long-Term Ecological Research (ILTER) network. ILTER is a global network of networks consisting of research sites in a wide array of ecosystems that focuses on long-term, site-based research, and builds on a “bottom-up” governance structure. To assess the biogeographical and socio-ecological representativeness of the ILTER site network, we analysed all of the 743 formally accredited sites in 47 countries with regard to their spatial distribution. So-called “Representedness” values were computed from six global datasets. The analysis revealed a dense coverage of Northern temperate regions and anthropogenic zones most notably in the US, Europe and East Asia. Notable gaps are present in economically less developed and anthropogenically less impacted hot and barren regions like Northern and Central Africa and inner-continental parts of South America. These findings provide the arguments for our recommendations regarding the geographic expansion for the further development of the ILTER network, most notably in inner continental parts of South America, the Arctic region and Western and Central Africa.
Simulation of ash clouds after a Laacher See-type eruption
Authors: Niemeier Ulrike , Riede Felix , Timmreck Claudia
Published: March 2021

The large explosive eruption of the Laacher See volcano c. 12,900 yrs BP marked the end of explosive volcanism in the East Eifel volcanic zone (Germany). We have reviewed the current evidence for the impact of the Laacher See Eruption (LSE) on the immediate and wider environment as recorded in a range of proxies with a series of interactive stratospheric aerosol model experiments. Recent studies about the climate impact of NH extratropical eruptions and new insights about the dating of the LSE warrant a return to this cataclysmic eruption and its potential influence on Northern Hemisphere climate. Rather detailed reconstructions of its eruption dynamics have been proposed. The eruption might have lasted several weeks or even months, most likely with an initial (~10h) intense early phase resulting in deposits over north-east Germany and the Baltic Sea, and a slightly later and weaker phase leaving deposits south of the volcano towards the Alps.

Our interactive stratospheric aerosol model experiments are based on a reference LSE experiment with emission estimates of 20 Tg of sulfur dioxide (SO2) and 200 Tg of fine-ash, across two eruptive phases in May and June. Additional sensitivity experiments reflect the estimated range of uncertainty of the injection rate and altitude and, assess how the solar-absorptive heating from the 150 Tg of sub-micron ash emitted in the first eruptive phase changed the LSE cloud’s dispersion. Our simulations reveal that the heating of the ash likely played an important role in the transport of ash and sulfate. Depending on the altitude of the injection, our simulated volcanic cloud begins to rotate shortly after the eruption. This meso-cyclone, as well as the additional radiative heating of the fine ash then changes the dispersion of the cloud to be more southerly compared to dispersal estimated without fine-ash heating. Sulfate transport is similarly impacted by the heating of the ash, resulting in a stronger transport to low-latitudes, later arrival of the volcanic cloud in the Arctic regions and a longer lifetime compared to cases without injection of fine ash.