bluuebunny/crossref_metadata_2025 huggingface dataset:
Using the alteration of magmatic monazite to constrain the thermal history of the Ryoke metamorphic belt (SW Japan)
Authors: Skrzypek Etienne , Shuhei Sakata , Dominik Sorger
Published: March 2020

The Ryoke plutono-metamorphic belt exposed in SW Japan is the type locality for low-Pressure/high-Temperature (LP/HT) metamorphism. The Ryoke metamorphic field gradient is, however, a complex object shaped by several deformation phases, multiple magmatic pulses and protracted metamorphism. In the western part of the Ryoke belt (Iwakuni-Yanai area), a petrological and geochronological study of two plutons emplaced before metamorphism is used to explore the behaviour of magmatic monazite along the LP/HT gradient and constrain the thermal history of the belt. We compare a massive granite adjoining schistose rocks affected by greenschist facies metamorphism with a gneissose granite adjoining migmatitic gneiss affected by upper-amphibolite facies conditions. Despite contrasting textures, the granite samples have similar mineral modes and compositions. Monazite in the massive granite is dominated by primary domains with limited secondary recrystallization, and is variably replaced by allanite+apatite±xenotime±Th−U-rich phases. Primary domains yield an average 206Pb/238U date of 102 ± 2 Ma while Th−U phases show Th−U−Pb dates of ca. 58 and 15−14 Ma. Monazite in the gneissose granite preserves sector- or oscillatory-zoned primary domains cross-cut by inclusion-rich secondary domains enriched in Ca, Y, U, P. Primary domain analyses are commonly discordant (116−101 Ma) while secondary domains preserve concordant 206Pb/238U dates spreading from 102 ± 3 to 91 ± 2 Ma.

Despite alteration, primary monazite domains preserve the age of magmatic crystallization for both plutons (102 ± 2 Ma and 106 ± 5 Ma). In the massive granite, monazite replacement is ascribed to the influx of aqueous fluid enriched in Ca+Al+Si±F during hydrothermal alteration below 500 °C. The oldest date (58 ± 5 Ma) obtained from the Th−U-rich alteration products is regarded as a minimum age for chloritization during final exhumation of the granite. In the gneissose granite a small amount of anatectic melt was responsible for a pseudomorphic recrystallization of monazite by dissolution-reprecipitation above 600 °C. The spread in 206Pb/238U dates for the secondary domains is attributed to incomplete isotopic resetting during dissolution-reprecipitation, and the youngest date of 91 ± 2 Ma is considered as the age of monazite recrystallization during a suprasolidus metamorphic event. These results reveal a diachronous, ca. 10 Ma-long HT history and an overall duration of about 15 Ma for the metamorphic evolution of the western part of the Ryoke belt.
World Stress Map Beyond Orientations - The First Quality Ranking Scheme for Stress Magnitude Data
Authors: Morawietz Sophia , Heidbach Oliver , Ziegler Moritz , Reiter Karsten , Rajabi Mojtaba , Zimmermann Günter , Müller Birgit , Tingay Mark
Published: March 2020

The World Stress Map (WSM) compiles orientations of the maximum horizontal stress SHmax and provides the only public global database of this kind. To make the SHmax orientation data from a wide range of stress indicators comparable, a quality ranking scheme has been developed. However, for the assessment of subsurface stability, not only the orientations but also data of the principal stress magnitudes are essential to calibrate 3D geomechanical-numerical models that deliver a continuous description of the complete 3D stress tensor. Thus, a comprehensive extension of the WSM database with quality-ranked stress magnitude data is needed. In a pilot study, we compiled an open-access stress magnitude database for Germany and adjacent regions, consisting of 568 data records. Indicators of stress magnitudes are diverse and include e.g. hydraulic fracturing and overcoring. To make data from different sources comparable, we developed a quality ranking scheme for stress magnitude data for the first time. In contrast to the established WSM quality ranking for SHmax orientation data records, estimates of stress magnitudes cannot be averaged over large rock volumes or depth ranges. Instead, each point-wise information has to be considered separately. Thus, we developed a new approach for the quality ranking scheme of Shmin magnitude data records which considers both the type of stress magnitude indicator and the degree of information availability. We present the results of our work including the data quality ranking scheme, which will serve as a template for a global stress compilation within the framework of the WSM project. The next countries and regions that we will explore are Australia, Scandinavia and India. We invite you to contribute to this project in your area or country of interest and to join the WSM team as an official collaborator.
Water Imbibition of Coal and its Potential Influence on CBM Recovery
Authors: Chang Yanhai
Published: March 2020

Water /gas mobility and interaction in coal plays an important role in achieving the high performance of coalbed methane (CBM) recovery. A large volume of fracturing fluid is permeated into reservoir during the CBM development. The effect of the imbibed liquid on gas recovery is still controversial. To better understand this phenomenon, a systematical investigation of water dynamic imbibition and matrix permeability change during water imbibition were conducted experimentally using different coals collected from Qinshui, Ordos and Junggar Basin of China.

The research stimulates two different case of spontaneous imbibition and the special imbibition process and imbibition in different pores are concluded by analyzing the imbibition characteristics (i.e. imbibition ability, imbibition rate and imbibition dynamic). The water imbibes into smaller pores and larger pores simultaneously, in which the water imbibition rate is relevant to the porosity, permeability and wettability. The water imbibition in coal matrix can bring about the redistribution and existing state change of water, which probably one of the main factors causing the damage of the matrix permeability. By studying the permeability change and imbibition law, a permeability model is used to explain the influence of imbibition on permeability. Finally, the permeability is found as a function of sorting time and invasion depth, which will be useful for field applications.
Generation of inertia-gravity waves in idealized baroclinic-wave life cycles: Explicit vs. semi-implicit time stepping in a finite-volume solver for the pseudo-incompressible equations
Authors: Schmid Fabienne , Gagarina Elena , Klein Rupert , Achatz Ulrich
Published: March 2020

Inertia–gravity waves (IGWs) emitted from jets and fronts are ubiquitous in the atmosphere and have a significant impact on atmospheric processes (Plougonven and Zhang, 2014). Since the mechanism responsible for the spontaneous emission of IGWs during the evolution of an initially balanced flow remain poorly understood, their representation in numerical weather prediction models is challenging (de la Cámara and Lott, 2015). Better understanding of this IGW source mechanism based on idealized numerical simulations is crucial to improve the accuracy of the forecasts. In this study, idealized baroclinic-wave life cycle experiments on the f-plane are performed to investigate spontaneous emission, using a finite-volume solver for the pseudo-incompressible equations (Rieper et al., 2013). In particular, the implementation of a semi-implicit time stepping scheme, along the lines of Smolarkiewicz and Margolin (1997) and Benaccio and Klein (2019), but adjusted to our staggered grid, permits longer simulation runs with much larger domains. A novelty is the implementation of a simple Newtonian heating function based on Held and Suarez (1994), which is used for forcing a baroclinically unstable temperature profile and allows the background state to vary in time (O’Neill and Klein, 2014). The results of the model with semi-implicit time stepping scheme will be documented and compared to an explicit Runge-Kutta scheme. The analysis may serve as a basis for the development and validation of a parameterization scheme for GWs emitted from jets and fronts.

References:

Benaccio, T., and R. Klein, 2019: A semi-implicit compressible model for atmospheric flows with seamless access to soundproof and hydrostatic dynamics. Mon. Wea. Rev., 147, 4221-4240.
de la Cámara, A., and F. Lott, 2015: A parameterization of gravity waves emitted by fronts and jets. Geophys. Res. Lett., 42, 2071-2078.
Held, I.M., and M.J. Suarez, 1994: A Proposal for the Intercomparison of the Dynamical Cores of Atmospheric General Circulation Models. Bull. Amer. Meteor. Soc., 75, 1825-1830.
O’Neill, W.P., and R. Klein, 2014: A moist pseudo-incompressible model. Atmos. Res., 142, 133-141. Plougonven R., and F. Zhang, 2014: Internal gravity waves from atmospheric jets and fronts. Rev. Geophys., 52, 33-76.
Rieper, F., Hickel, S., and U. Achatz, 2013: A conservative integration of the pseudo-incompressible equations with implicit turbulence parameterization. Mon. Wea. Rev., 141, 861-886. Smolarkiewicz, P.K., and L.G. Margolin, 1997: On forward-in-time differencing for fluids: an Eulerian/semi-Langrangian nonhydrostatic model for stratified flows. Atmosphere-Ocean, 35, 127- 152.
Antarctic climate response to large volcanic eruptions in the historical period
Authors: Silva Natália , Wainer Ilana , Khodri Myriam
Published: March 2020

Large tropical volcanic eruptions are well known to change the global climate and maybe even interfere with some natural modes of variability such as El Niño Southern Oscillation. As they inject a high amount of sulfur gas into the stratosphere, sulfate aerosol loading increases a few months after the eruption, which is then transported globally. Large tropical events may, therefore, affect extratropical climate variability. For example, temperature changes have been identified in Antarctica after the Pinatubo eruption in 1991, as warming in the peninsula. However, a causal link with the eruption and, more generally, a possible influence of large tropical volcanic eruptions on the Southern Hemisphere climate are still open questions. In this study we aim to focus on the five biggest eruptions of the historical period (Krakatau — Aug/1883, Santa María — Oct/1902, Mt Agung — Mar/1963, El Chichón — Apr/1982 and Pinatubo — Jun/1991) by assessing two CMIP6 class models (IPSL-CM6A-LR Large Ensemble and BESM) and two Reanalyses (NOAA 20th Century Reanalysis and ECMWF's ERA 20th Century).
Structure-activity relationships for unimolecular reactions of peroxy radicals, RO2, at atmospheric temperatures
Authors: Vereecken Luc , Vu Giang H. T. , Nguyen Hue M. T.
Published: March 2020

The oxidation of most organic matter emitted to the atmosphere proceeds by radical reaction steps, where peroxy radicals, ROO•, are critical intermediates formed by addition of O2 molecules to carbon-based radicals. The chemistry of these RO2 radicals in high-NOx conditions is well-known, forming alkoxy radicals and NO2. In low-NOx and pristine conditions, the RO2 radicals react with HO2 and other R'O2 radicals, but can have a sufficiently long lifetime to also undergo unimolecular reactions. Hydrogen atom migration, forming a hydroperoxide (-OOH) and a new peroxy radical site after addition of an additional O2 on the newly formed radical site, has been studied extensively in some compounds, such as isoprene where it was shown to be the a critical step in OH radical regeneration. RO2 ring closure reactions have likewise been studied, where for β-pinene it has been shown to be a critical step governing the yield of the decomposition products such as acetone and nopinone.

Despite the interest in RO2 unimolecular reactions, and the potential impact on atmospheric chemistry, no widely applicable structure-activity relationships (SARs) have been proposed to allow systematic incorporation of such unimolecular reactions in gas phase atmospheric kinetic models. In this work, we present a series of systematic theoretical predictions on the site-specific rate coefficients for such reactions for a wide range of molecular substitutions. Combined with extensive literature data this allows for the formulation of a SAR for RO2 unimolecular reactions, covering aliphatic, branched, and unsaturated RO2 with oxo, hydroxy, hydroperoxy, nitrate, carboxylic acid, and ether substitutions.

The predictions are compared to experimental and theoretical data, including multi-functionalized species. Though some molecular classes are well represented in the training set (e.g. aliphatic RO2), other classes have little data available and additional work is needed to enhance and validate the reliability of the SAR. Direct experimental data is scarce for all RO2 classes. The fastest H-migrations are found to be for unsaturated RO2, with the double bond outside the H-migration TS ring. Ring closure of unsaturated RO2 are likewise fast if the product radical carbon is exocyclic to the newly formed peroxide ring.
Karst Topography Analysis Based on Multi-sensor (UAS & LiDAR) Data Acquisition
Authors: Konsolaki Aliki , Vassilakis Emmanuel
Published: March 2020

The state-of-the-art in surveying of open surface the last few decades is based on Point Cloud processing and interpretation. Lately, similar technology tends to be used for indoor surveying as well. One of the extreme applications is the use of the exact same technology in underground karstic cavities, evolving the methodology used in cave mapping. Geometric and morphometric analysis of the caves or any containing components (speleothems) include various techniques aiming at quantifying their dimensions in order to determine the characteristics and consequently the relationship between the cavity morphology and the surrounding structural, lithological and hydrogeological properties. The purpose of this research is to combine high resolution topographic data acquired with different instruments for both the underground morphology of a karstic cave (Koutouki, Peania, Greece) and the open-air surface above it. The described methodology is based on photogrammetric processing of Unmanned Aerial System image data and the extraction of a point cloud recorded with the use of a handheld laser scanning system. The latter resulted a 3D model of the cave and led to the production of a digital relief for the roof of the cave, which in turn was combined with the digital terrain model of the open-air surface above the cave. The final product is a high-resolution information layer with measurements of the rock thickness between the roof of the underground karstic structure and the open-surface topography with high accuracy.
A breakdown of ENSO-North Pacific Teleconnection in early January
Authors: Park Chang-Hyun , Son Seok-Woo , Choi Jung
Published: March 2020

During El Niño winters, East Asia and western North America become anomalously warm because of the combined effect of anti-cyclonic circulation anomaly over Kuroshio Extension and Philippine sea, and an enhanced Aleutian Low. However, this El Niño-Southern Oscillation (ENSO)-North Pacific teleconnection disappears in early January. In this study, we suggest that this breakdown in regional teleconnection is partly due to Madden-Julian Oscillation (MJO). In early December of El Niño winters, MJOs frequently form and reach at Western Pacific, causing positive intraseasonal Pacific North American (PNA)-like teleconnection, which is same pattern to the El Niño teleconnection. In mid-December, however, as MJOs are frequently organized over Indian Ocean, it causes a destructive interference, cancelling El Niño teleconnection in early January. Although weak and not statistically significant, this sharp decline of ENSO teleconnection in early January also appears in La Niña winters. A preference of MJO organization and its propagation in ENSO winters are explained by moist static energy anomalies in the west Indian Ocean. This result suggests that MJO is important for predicting ENSO teleconnection on intraseasonal scales.
Dynamics of zonal mean characteristics of circulation in stratosphere and mesosphere in winter
Authors: Zorkaltseva Olga , Mordvinov Vladimir , Dombrovskaya Natalia , Pogoreltsev Alexander
Published: March 2020

The model of the middle and upper atmosphere circulation (MUAM) and the data of the ERA-interim archive are used to study the mean zonal variations of wind velocity and temperature in the middle atmosphere. Comparison of model calculations and data of ERA-interim archives showed that the model adequately reproduces the main features of circulation processes in the winter stratosphere. The analysis of variations in the mean zonal characteristics of the atmosphere is show that synchronous variations there are in wind velocity and temperature in the stratosphere and mesosphere in the range of 10-30 days . These synchronous variations occupy long latitudinal zones horizontally (tens degree) and have a significant length vertically (tens km). The sign of the variations change horizontally in the region of jet streams (and does not change at the equator), and the vertical change of sign occurs in areas of the stratopause and the mesopause. The nature of  the variations practically does not depend on the phase of the quasi-biennial cycle in the Equatorial stratosphere. The variations are global scale and are reminiscent of the fluctuations in the meridional circulation cells. The dynamic processes of destruction of the polar vortex during sudden stratospheric warming are coordinated with these synchronous variations.

Acknowledgements. This work was supported by the Russian Science Foundation, project No. 19-77-00009.  The authors gratefully acknowledge the access to the ECMWF ERA-Interim.
Modeling of the Dec 24, 2018 eruptive intrusion at Etna volcano by data of multi-disciplinary continuous deformation networks (CGPS, borehole strainmeters and tiltmeters)
Authors: Aloisi Marco , Bonaccorso Alessandro , Cannavò Flavio , Currenti Gilda , Gambino Salvatore
Published: March 2020

In the previous EGU 2019 we presented the different data acquired by the multi-disciplinary deformation networks during the eruption of Etna on 24 December 2018, when the volcano was suddenly penetrated by a violent dyke intrusion. An eruptive fissure opened and continued to propagate southward for more than 10 hours. The situation created the fear of possible serious consequences of feeding a lava flow even at medium-low altitudes, therefore potentially hazardous for the villages and infrastructures located there. However, the propagation stopped and lava flows finished on 25 December.

In this updated study we present the effort made to model the complex eruptive process characterized by two attempts of intrusion. We inferred a first dyke starting from the sea level depth with an increasing of its dimension in the shallower part. Successively and until the early hours of 25 December, we revealed a second attempt of intrusion characterized by a dyke with a powerful opening with respect to the first dyke but that, fortunately, did not reach the free surface. We describe how different types of continuous deformation data provide complementary information on the ongoing process allowing us to model the fast intrusive process. In particular, the high-precision borehole instruments (strainmeters and tiltmeters) provided a robust early warning; the displacement field measured by high-rate GPS allowed obtaining an early but also reliable model of the source. Finally, the integration of all the continuous data constrained a more detailed and complete model and its time evolution able to represent the complex process leading to this flank eruption.

 
Organic matter content controls the N and P degradation process on biogeochemical interfaces: A micro-ecosystem scale study based on SoilChips-XPS-Zymography integrated technique in paddy soils
Authors: Wei Liang
Published: March 2020

The biogeochemical interfaces are hotspots for organic matter (OM) transformation. However, direct and continuouxiacis tracing of OM transformations and N and P degradation processes are lacking due to the heterogeneous and opaque nature of soil microenvironment. To investigate these processes, a new soil microarray technology (SoilChips) was developed and used. Homogeneous 2-mm-diameter SoilChips were constructed by depositing a dispersed paddy soils with high and low soil organic carbon (SOC) content. A horizon suspension on a patterned glass. Dissolved organic matter from the original soil was added on the SoilChips to mimic biogeochemical processes on interfaces. The chemical composition of biogeochemical interfaces were evaluated via X-ray photoelectron spectroscopy (XPS) and the two-dimensional distribution of enzyme activities in SoilChips were evaluated by zymography. Over 30 days, soil with high SOC content increases microbial nutrition (N and P) requirements than soil with low SOC evidenced by higher hotspots of β-1,4-N-acetaminophen glucosidase, and acid phosphomonoesterases and higher 16S rRNA gene copies. The degree of humification in dissolved organic matter (DOM) was higher and the bioavailability of DOM was poorer in soil with high SOC than soil with low SOC. The poorest bioavailability of DOM was detected at the end of incubation in soil with high SOC. Molecular modeling of OM composition showed that low SOC mainly facilitated the microbial production of glucans but high SOC mainly facilitated the microbial production of proteins. We demonstrated that SOC content or DOM availability for microorganisms modifies the specific OM molecular processing and N and P degradation processes, thereby providing a direct insight into biogeochemical transformation of OM at micro-scale.
Environment, diversity, evolution and Cope's Rule: Drivers of size in planktonic foraminifera.
Authors: Birch Heather , Schmidt Daniela N. , Jones Chloe , Robinson Marci M. , Fraass Andy
Published: March 2020

Within the marine fossil record, size is a fundamental trait providing information on both assemblages and individual species. Changes in size within an assemblage are largely driven by species composition typically related to environmental conditions. Changes in size of an individual species can be an indicator of health and whether optimal growth conditions (i.e. temperature, salinity and food availability) prevail. Over evolutionary timescales, individuals tend to increase in size (Cope’s rule) also altering the average size of the population.

The Pliocene provides an excellent opportunity to look at environmental drivers and ecological responses to a warmer world, at high resolution and with extant species. A short glaciation phase, during marine isotope stage (MIS) M2, interrupted the Pliocene global warming between ~ 3.31 – 3.26 Ma. This event provides the ideal framework to quantify how biota, already adapted to warming conditions, respond to a short, but substantial cooling event. 

We analysed the size and species composition of samples collected as part of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project from a variety of locations around the globe. The samples cover the Atlantic, Indian and Pacific oceans at a range of latitudes (e.g. DSDP Site 521, 586, 607 and ODP Site 716, 754, 887). We measured the maximum diameter of planktonic foraminifera tests with a fully automated light microscope, enabling high resolution sampling at a multitude of sites, before, during and after the MIS M2 glaciation event. On average 2000 specimens were measured per sample, resulting in over a million analyses in total. Changes in planktonic foraminiferal assemblage composition were characterised by quantifying relative species abundances and augmented by determining the largest species.

Planktonic foraminiferal assemblage size shows a general increase during the Pliocene likely related to warming temperatures. What is unclear is if this change is driven by changes in diversity due to extinction and origination, responses to environmental change or a general increase in size of species found through the record. Here we discuss reactions of species and (or) ecological groups to environmental change and determine the individual drivers of size change across the world’s oceans.
REMOLAND: New high-resolution surface boundary data for the regional climate model REMO and their impacts
Authors: Ziegler Katrin , Pollinger Felix , Abel Daniel , Paeth Heiko
Published: March 2020

In cooperation with the Climate Service Center Germany (GERICS) we want to improve the land surface module in the regional climate model REMO. Due to the need of high-resolution regional climate models to get information about local climate change, new data and new processes have to be integrated in these models.

Based on the REMO2015 version and focusing on EUR-CORDEX region we included and compared five different high-resolution topographic data sets. To improve the thermal and hydrological processes in the model’s soil we also tested three new soil data sets with a much higher spatial resolution and with new parameters for a new soil parameterization.
CFD simulations of tsunamis from large scale propagation up to local coastal impacts
Authors: Marcer Richard , Journeau Camille , Pons Kévin
Published: March 2020

This work has been performed within the framework of the TANDEM project (Tsunamis in northern AtlaNtic: Definition of Effects by Modelling) which is dedicated to the appraisal of coastal effects due to tsunami waves on the French coastlines. One of the identified objectives of TANDEM consisted in designing, adapting and validating numerical codes for tsunami hazard assessment, addressing the various stages of a tsunami event: generation, propagation, run-up and coastal inundation.

PRINCIPIA has been working on the development and qualification of two in-house CFD software’s: a 2D Saint-Venant model (often called NLSW for Non-Linear Shallow Water) using an Adaptive Mesh Refinement (AMR) for simulation of large scale tsunami propagation from the source up to coastal scale, and a 3D Navier-Stokes model dedicated to tsunami coastal impact modelling.

An overview of the results obtained with both codes aiming at being applicable to tsunami modelling, is presented. The validation process has been done on several academic test cases having experimental data for comparisons, as the breaking of a solitary wave on a reef, the generation of a long wave induced by a vertical bloc (massive cliffs, ice bodies) falling down an underlying water volume, the tsunami generation due to a submarine landslide and the tsunami impact on a coastal city.

A real case simulation is concerned as well, the devastating 2011 Tohoku event which is compared with in-situ data.

The work was supported by the Tandem project in the frame of French PIA grant ANR-11-RSNR-00023.
Synoptic conditions and atmospheric moisture pathways associated with virga and precipitation over coastal Adélie Land, Antarctica
Authors: Jullien Nicolas , Vignon Etienne , Sprenger Michael , Aemisegger Franziska , Berne Alexis
Published: March 2020

Precipitation falling over the coastal regions of Antarctica often experiences low-level sublimation within the dry katabatic layer. The amount of water that reaches the ground surface is thereby considerably reduced. We investigate the synoptic conditions and the atmospheric transport pathways of moisture that lead to virga – when precipitation is completely sublimated – or actual surface precipitation at Dumont d’Urville (DDU) station, coastal Adélie Land, Antarctica. We combine ground-based radar measurements, Lagrangian back-trajectories, Eulerian diagnostics of extratropical cyclones and fronts as well as with moisture source estimations based on ERA5 reanalyses. Virga periods – corresponding to 36% of the precipitating events – often precede and sometimes follow surface precipitation periods. Pre-precipitation virga, surface precipitation and post-precipitation virga correspond to different phases of the same precipitating system. Precipitation and virga are always associated with the warm front of an extratropical cyclone that sets to the west of coastal Adélie Land but the exact locations of the cyclone and front differ between the three phases. On their way to DDU, the air parcels that ultimately precipitate above the station experience a large-scale lifting across the warm front. The lifting generally occurs earlier in time and farther from the station for virga than for precipitation. It is further shown that water contained in the precipitation falling above DDU during pre-precipitation virga has an oceanic origin farther away (30 degrees more to the west) from Adélie Land than the one that precipitates down to the ground surface.
Biotic and abiotic controls on carbon storage in aggregates from grassland soils in the Northern Limestone Alps of Germany
Authors: Garcia-Franco Noelia , Wiesmeier Martin , Walter Roswitha , Colocho-Hurtarte Luis Carlos , Buness Vincent , Berauer Bernd Josef , Zistl-schlingmann Marcus , Kiese Ralf , Dannenmann Michael , Kögel-Knabner Ingrid
Published: March 2020

Alpine and pre-alpine grassland soils in Bavaria provide important ecosystem services and are hotspots for soil organic carbon (SOC) storage.  However, information on the underlying factors that control SOC stabilization via soil aggregation is limited. In three grassland soils with the same parent material but at different elevation (Fendt: 600 m.a.s.l, Graswang: 860 m a.s.l and Esterberg: 1,260 m a.s.l), we studied the soil aggregate distribution and associated SOC according to aggregate size classes (large-macroaggregates > 2,000 µm, small-macroaggregates 250-2000 µm, microaggregates 63-250 µm, silt plus clay particles <63 µm). Furthermore, the biomass and abundance of different ecological groups of earthworms were determined. Our results showed an increase in SOC contents and aggregate stability with elevation. SOC and N stocks of bulk soils showed the same trend as OC contents in aggregates.  Principal component analysis revealed that carbonates, SOC, aboveground plant biomass and the earthworm biomass are the main facilitating agents of aggregation and SOC and N storage in grassland soils of the Northern Limestone Alps of Germany
A Study on Contribution of the Advective Heat Flux to the Energy Closure near the Land Surface in the Zoige Alpine Wetland
Authors: Wen Jun , Lu Xuancheng , Yang Yue , Tian Hui , Liu Wenhui , Wu Yueyue , Jiang Yuqing
Published: March 2020

The energy non-closure near the land surface has been a key topic in the land surface processes research.  The energy closure rate is still not high even after considering heat storage and photosynthesis energy consumption, while the contribution of advective energy to the closure rate needs to be considered further under the non-uniform underlying surface. In this paper, the advective energy caused by thermal heterogeneity of underlying surface is calculated by using the energy budget data collected from the Flower-Lake observation site in the Zoige Alpine Wetland in 2017, and the contribution of thermal advection to energy closure near the ground is estimated. The result shows: In summer of 2017, the maximum value of the advective heat flux was 23.8w/m2 at the Zoige alpine wetland. When the contribution of advective heat flux is introduced into the energy balance equation, the energy closure rate increases from 72.0% to 79.4%. With considering the contribution of horizontal heat transfer, it has a certain effect on improving energy closure rate for the flat terrain and thermal inhomogeneous underlying surface. The near surface thermal inhomogeneity leads to the accumulation of heat, which is the basic reason for the heat advection to affect the energy closure rate, and also an important reason for the difference between the wetland characteristics of water and heat exchange of the wetland with the other regions.

Key words：Alpine wetland; eddy correlation; advective heat flux; energy closure rate; inhomogeneous land surface
Ice-contact deltas investigation using ground penetrating radar (GPR), sedimentology, electrical resistivity tomography (ERT) and , Salpausselka I and II near Lahti, Finland
Authors: Kurjanski Bartosz , Rea Brice , Spagnolo Matteo , Cornwell David , Palmu Jukka-Pekka , Howell John , Quiros Andres , Comte Jean-Christophe
Published: March 2020

In Finland, two large “moraine” ridges (Salpausselka I and Salpausselka II), extending to over 600 km in length, delineate two major stillstand/readvance positions of the Fennoscandian ice sheet during the last deglaciation (Glückert, 1986). They are inferred to be chronologically related to the cold stage known as the Younger Dryas which occurred at the end of the last glaciation. During this time the Baltic ice lobe and the Finnish Lake District ice lobe, constituting a part of the southern margin of the Fennoscandian ice sheet, were grounded in a large proglacial lake, the Baltic ice lake, a predecessor to the modern-day Baltic Sea. The “moraine” ridge is mostly composed of glaciofluvial sands, gravels and boulders rather than diamicton and deposited on crystalline, impermeable bedrock and constitute  freshwater aquifer in southern and eastern Finland. The average thickness of ice-contact deltas sediments is estimated at between 20 and 60 meters and is highly variable.

Outcrop studies are combined with GPR and ERTprofiles to provide insight into the aquifer architecture at different scales and depths of investigation. This study aims to improve our understanding of such deposits in the subsurface, especially about their internal structure, sedimentary facies distribution and potential barriers and/or baffles to fluid flow and poro-perm characteristics.
Deep convection in the Lofoten Basin: ARGO vs MITgcm
Authors: Fedorov Aleksandr , Tatyana Belonenko
Published: March 2020

The Lofoten basin (the LB) contains relatively warm and salty waters regarding border basins such as Greenland and Barents Seas. Variability of the processes inside occurring in the basin reflects on the climate as on the mesoscales as on the interannual scales. We use a term mixed layer depth (MLD) as a border of the pycnocline in the water column, this parameter lets us evaluate the intensity of the convection in the region. Several methods of MLD calculations are tested in the current study: Kara, Montegut, and Dukhovskoy. The convection in the basin destructs stratification and forms massive intermediate water mass. The MITgcm data for 1993-2012 and over 5000 in-situ Argo T, S profiles for 2001-2017 were used in the calculations of the MLD.

We consider the maximum MLD (mMLD) in the region and its spatial distribution. The mMLD is higher in the central part of the LB and corresponds to the location of the Lofoten basin eddy (the LBE). Here the mMLD reaches 1000 meters, the medium maximum is 400 meters based both on the in-situ and model data. The maximum mixed layer depth ​​varies in the range of 400-1000 meters according to both datasets were used. The MLD over 400 meters is observed from January to May every year.

Acknowledgments: The authors acknowledge the support of the Russian Science Foundation (project No. 18-17-00027). The results of the MITgcm were provided by D.L. Volkov, Cooperative Institute for Marine and Atmospheric Studies, University of Miami, USA.
A Bayesian framework for emergent constraints: case studies of climate sensitivity with PMIP
Authors: Renoult Martin , Annan James , Hargreaves Julia , Sagoo Navjit , Flynn Clare , Kapsch Marie-Luise , Mikolajewicz Uwe , Ohgaito Rumi , Mauritsen Thorsten
Published: March 2020

In this study we introduce a Bayesian framework, which is flexible and explicit about the prior assumptions, for using model ensembles and observations together to constrain future climate change. The emergent constraint approach has seen broad application in recent years, including studies constraining the equilibrium climate sensitivity (ECS) using the Last Glacial Maximum (LGM) and the mid-Pliocene Warm Period (mPWP). Most of these studies were based on Ordinary Least Squares (OLS) fits between a variable of the climate state, such as tropical temperature, and climate sensitivity. Using our Bayesian method, and considering the LGM and mPWP separately, we obtain values of ECS of 2.7 K (1.1 - 4.8, 5 - 95 percentiles) using the PMIP2, PMIP3 and PMIP4 data sets for the LGM, and 2.4 K (0.4 - 5.0) with the PlioMIP1 and PlioMIP2 data sets for the mPWP. Restricting the ensembles to include only the most recent version of each model, we obtain 2.7 K (1.1 - 4.3) using the LGM and  2.4 K (0.4 - 5.1) using the mPWP. An advantage of the Bayesian framework is that it is possible to combine the two periods assuming they are independent, whereby we obtain a slightly tighter constraint of 2.6 K (1.1 - 3.9). We have explored the sensitivity to our assumptions in the method, including considering structural uncertainty, and in the choice of models, and this leads to 95% probability of climate sensitivity mostly below 5 and never exceeding 6 K. The approach is compared with other approaches based on OLS, a Kalman filter method and an alternative Bayesian method. An interesting implication of this work is that OLS-based emergent constraints on ECS generate tighter uncertainty estimates, in particular at the lower end, suggesting a higher bound by construction in case of weaker correlation. Although some fundamental challenges related to the use of emergent constraints remain, this paper provides a step towards a better foundation of their potential use in future probabilistic estimation of climate sensitivity.
Sea level in the Global Geodetic Observing System
Authors: Bradshaw Elizabeth , Matthews Andy , Gordon Kathy , Hibbert Angela , Jevrejeva Sveta , Rickards Lesley , Williams Simon , Woodworth Philip
Published: March 2020

The Permanent Service for Mean Sea Level (PSMSL) is the global databank for long-term mean sea level data and is a member of the Global Geodetic Observing System (GGOS) Bureau of Networks and Observations. As well as curating long-term sea level change information from tide gauges, PSMSL is also involved in developing other products and services including the automatic quality control of near real-time sea level data, distributing Global Navigation Satellite System (GNSS) sea level data and advising on sea level metadata development.
At the GGOS Days meeting in November 2019, the GGOS Focus Area 3 on Sea Level Change, Variability and Forecasting was wrapped up, but there is still a requirement in 2020 for GGOS to integrate and support tide gauges and we will discuss how we will interact in the future. A recent paper (Ponte et al., 2019) identified that only “29% of the GLOSS [Global Sea Level Observing System] GNSS-co-located tide gauges have a geodetic tie available at SONEL [Système d'Observation du Niveau des Eaux Littorales]” and we as a community still need to improve the ties between the GNSS sensor and tide gauges. This may progress as new GNSS Interferometric Reflectometry (GNSS-IR) sensors are installed to provide an alternative method to observe sea level. As well as recording the sea level, these sensors will also provide vertical land movement information from one location. PSMSL are currently developing an online portal of uplift/subsidence land data and GNSS-IR sea level observation data. To distribute the data, we are creating/populating controlled vocabularies and generating discovery metadata.
We are working towards FAIR data management principles (data are findable, accessible, interoperable and reusable) which will improve the flow of quality controlled sea level data and in 2020 we will issue the PSMSL dataset with a Digital Object Identifier. We have been working on improving our discovery and descriptive metadata including creating a use case for the Research Data Alliance Persistent (RDA) Identification of Instruments Working Group to help improve the description of a time series where the sensor and platform may change and move many times. Representatives from PSMSL will sit on the GGOS DOIs for Data Working Group and would like to contribute help with controlled vocabularies, identifying metadata standards etc. We will also contribute to the next GGOS implementation plan.
Ponte, Rui M., et al. (2019) "Towards comprehensive observing and modeling systems for monitoring and predicting regional to coastal sea level." Frontiers in Marine Science 6(437).
MOTEDAS Century Database, Part 2: spatial variation of temperature trends: the UP-TO-DATE effect.
Authors: Sandonis Leire , Peña-Angulo Dhais , Bruneti michele , Beguería Santiago , Gonzalez-Hidalgo José Carlos
Published: March 2020

We have finished the complete digitalization of Annual Books from the Spanish meteorological service (AEMET) between 1916 to 1949. Data retrieved included monthly means of maximum and minimum temperature. In the present contribution we are going to show the new MOTEDAS_Century dataset (MOnthly TEmperature Dataset of Spain century) which has been performed matching data from the annual books and data from the national climate data bank of AEMET. The amount of stations with temperature data vary from a minimum of 228 (1938) and 2.030 (1994). This length of the time series is sometimes very short. Since we aim to analyse the information with a highest spatial density as possible we decided, instead of reconstructing series, to reconstruct monthly fields independently by using all the information available month to month between 1916 and 2015. Monthly interpolated data were converted to a high-resolution grid (10x10 km) using the Angular Distance Weighting method, resulting into a 5000 pixels grid.

The time series of annual mean temperature in Spanish mainland from 1916 to 2015 shows the well-known pattern of increase during the first decades, a slowdown in the middle of the 20th century, and the final rise since the 1970´s, including a final stage without significant trend for the last three decades.

MOTEDAS_Century´s annual temperature average series has been compared with other analogous series from BEST (Berkelay Earth Surface Temperature) and SDAT (Spanish Daily Adjusted Temperature Series) datasets, as well as the twentieth century reanalysis for the Iberian Peninsula. The different versions resemble the global pattern, although differences exist particularly during the last three decades. The comparison of the annual mean temperature series with their counterparts in the BEST, AEMET and SDAT databases suggests that processing the newly retrieved information does not modify the behaviour patterns of mean annual temperatures in the Spanish mainland, and that the difference observed among the various sources can be attributed to a combination of effects from the different number of weather stations examined, which is very much higher in MOTEDAS_century, to the local characteristics of stations. The MOTEDAS_century grid in the anomalies format is available on request from the authors and will be in future on the website of the CLICES Project (http://clices.unizar.es).
The terraces of Petra, Jordan: archives of a lost agricultural hinterland
Authors: Bäumler Rupert , Lucke Bernhard , Birk Jago , Keilholz Patrick , Hunt Christopher O. , Laparidou Sofia , Abu-Jaber Nizar , Kouki Paula , Fiedler Sabine
Published: March 2020

Petra is hidden in rugged arid mountains prone to flash floods, while the dry climate and barren landscape seem hostile to cultivation. Nevertheless, there are countless remains of terraces of so far unknown purpose. We investigated three well-preserved terraces at Jabal Haroun to the south-west of Petra which seemed representative for the diverse geology and types of terraces. A hydrological model shows that the terraces were effective at both control of runoff and collection of water and sediments: they minimized flash floods and allowed for an agricultural use. However, rare extreme rainfall events could only be controlled to a limited degree, and drought years without floods caused crop failures. Pollen and phytoliths in the sediments attest to the past presence of well-watered fields including reservoirs storing collected runoff, which suggest a sophisticated irrigation system. In addition, faeces biomarkers and plant-available phosphorus indicate planned manuring. Ancient land use as documented by the terraces created a green oasis in the desert. They seem to represent Petra's agricultural hinterland, which was lost during the Islamic period due growing aridity and an increased frequency of devastating extreme precipitation events. The heirs of the Nabateans reverted to their original Bedouin subsistence strategies but continue to opportunistically cultivate terrace remains.
How to adapt a nonurban model structure to account for urbanization?
Authors: Saadi Mohamed , Oudin Ludovic , Ribstein Pierre
Published: March 2020

A catchment-scale hydrological model encompasses a set of hypotheses that are capable of describing, in a lumped way, the water movement in a hydrological catchment. As the catchment undergoes a heavy urbanization gradient, the catchment’s hydrological behavior changes. A new set of hypotheses is then needed to consider the presence of urban-introduced features in the hydrological cycle. Our objective is to reach a parsimonious model structure that is capable of sufficiently reproducing the rainfall-runoff relationship along a wide range of urbanization levels, including the non-urbanized situation. Given a model that is adequate for non-urbanized catchments, what modifications should one operate on the initial model hypotheses to account for (1) the presence of impervious surfaces within the catchment and (2) the interactions between the pervious and the newly added impervious surfaces? To this aim, a large sample of 268 American and French urbanized catchments was prepared. We have chosen an initial hydrological model, GR4H, whose structure has been tested and improved using large international samples of catchments, but predominately non-urbanized. Analyzing the hydrological behavior of the urbanized catchments has helped us in formulating a set of modifications to be made on the initial model structure. Step by step, the relevance of each modification was assessed using 10 continuous, frequency- and event-based evaluation criteria. As a result, the model performances were significantly improved when (a) the net rainfall production was considered to be controlled not only by the antecedent soil moisture conditions but also by the catchment’s mean imperviousness, mainly during low-intensity rainfall events, and (b) the fast flow branch was more privileged in routing, seeing that the response of the urbanized catchments was faster and highly reactive in comparison with the rural ones’. Unlike the initial model structure, the resulting one can help quantifying the impact of future urbanization schemes on the catchment’s hydrological behavior.