bluuebunny/crossref_metadata_2025 huggingface dataset:
Elliptical Versus Cylindrical Magma Conduits
Authors: Eaton Eliot , Neuberg Jurgen , Marsden Luke
Published: March 2021

By modelling the magnitude and spatial distribution of surface displacement induced by different representations of magma conduits, more informed decisions can be made for the deployment of real-time monitoring devices, such as tiltmeters, and aid interpretations of stress changes within the subsurface. The existence of varying forms of magma conduit is widely known, despite this, the effect of laterally elongated conduits on magma flow processes and resulting surface deformation at volcanoes has not been systematically explored.

By varying the ellipticity of the volcanic conduit cross-section we assess the relative importance of laterally elongated conduits when considering flow processes and surface deformation. The scenario of magma ascent through a dyke that changes into a cylindrical conduit closer to the surface is also considered, herein referred to as a complex conduit. Both shear stress on the conduit walls due to viscous magma flow resistance and the pressurisation of conduits are used as source mechanisms.

When considering the pressurisation of different conduit geometries, the displacement field induced by an elongated conduit (where semi-axes a and b of the elliptical cross-section equal a=10b) is an order of magnitude larger than that of a cylindrical conduit. Moreover, for the case of the complex conduit, the displacement field is dominated by the dyke form of the deeper conduit, with little influence from the transition region between elongated and cylindrical conduit. When considering shear stress as a source mechanism, the displacement field induced is primarily vertical and radially symmetric even at the smallest spatial scales ($<1$ km), independent of ellipticity of conduit origin. The ellipticity of conduits with equal cross-sectional area has a significant control on the flow rate, and therefore, the magnitude of shear stress achieved under equal pressure gradients. The deformation resulting from shear stress on the conduit walls is also influenced by the depth of rheological changes within the magma and the inter-dependency with conduit geometry.
Seismic shaking scenarios for city of Zagreb, Croatia
Authors: Latečki Helena , Stipčević Josip , Molinari Irene
Published: March 2021

In order to assess the seismic shaking levels, following the strong Zagreb March 22nd 2020 earthquake, we compute broadband seismograms using a hybrid technique. In a hybrid technique, low frequency (LF, f < 1 Hz) and high frequency (HF, f = 1–10 Hz) seismograms are obtained separately and then merged into a single time series. The LF part of seismogram is computed using a deterministic approach while for the HF part, we adopt the semi-stochastic method following the work of Graves and Pitarka (2010). For the purposes of the simulation, we also assemble the 3D velocity and density model of the crust for the city of Zagreb and its surrounding region. The model consists of a detailed description of the main geologic structures that are observed in the upper crust and is embedded within a greater regional EPCrust crustal model (Molinari and Morelli, 2011). To test and evaluate its performance, we apply the hybrid technique to the Zagreb March 22nd 2020 Mw = 5.3 event and four smaller (3.0 < Mw < 5.0) events. We compare the measured seismograms with the synthetic data and validate our results by assessing the goodness of fit for the peak ground velocity values and the shaking duration. Furthermore, since the 1880 Mw = 6.2 historic earthquake significantly contributes to the hazard assessment for the wider Zagreb area, we compute synthetic seismograms for this event at two different hypocenter locations. We calculate broadband waveforms on a dense grid of points and from these we plot the shakemaps to determine if the main expected ground-motion features are well-represented by our approach. Lastly, due to the events that occured in the Petrinja epicentral area at the end of 2020, we decided to extend our 3D model to cover the area of interest. We will present the preliminary results of the simulation for the December 29th 2020 Mw = 6.4 strong earthquake, as well as our plans for further research.
New lead isotope data on Cretaceous volcanic rocks of Mongolia: the sources and the origin of the magmatic melts
Authors: Kuznetsov Maksim , Savatenkov Valery , Lidia Shpakovich , Alexander Kozlovskiy , Ekaterina Kudryashova
Published: March 2021

The Eastern Mongolia Volcanic Area (EMVA) and the Gobi-Altai Volcanic Area (GAVA) are large parts of the Late Mesozoic volcanic-plutonic belt which is located in northeast Asia. The main value of the EMVA and the GAVA was formed during the Cretaceous. Previous research devoted to Cretaceous volcanic rocks of both volcanic areas has focused mainly on its geochemical features of main and trace components, and Nd – Sr isotope composition (Bars et al., 2018; Dash et al., 2015; Sheldrick et al., 2018; Sheldrick et al., 2020). At the same time, the published data on the Pb isotope composition of volcanic rocks of the EMVA and the GAVA is too scarce (Sheldrick et al., 2018; Sheldrick et al., 2020). However, the Pb isotope characteristic can be a key to the understanding of parent melts sources of the EMVA and the GAVA rocks.  Therefore, the goal of the presented work is a more extensive study of the Pb isotope systematics of the Cretaceous volcanic complexes within the EMVA and the GAVA.

Obtained data on Pb isotope characteristics of the EMVA volcanic rocks demonstrate the role of the upper crust terrigenous component (UCC) in magma generation. The role of the UCC in the EMVA formation is consistent with the Nd – Sr isotope composition and elevated LILE contents in rock samples. In contrast to the EMVA the Pb isotope features of the same aged GAVA rocks (135 – 120 Ma) with the enriched Nd – Sr composition point to the role of the lower crust component in their formation. Thus, there is a difference between the sources of the coeval rocks of two volcanic areas reflecting the difference in the melts source composition between the two areas.

The Late Cretaceous rocks of the GAVA (about 90 Ma), as well as the Early Cretaceous rocks of the EMVA, lie nearby a field of lithospheric mantle xenoliths on the Pb isotope ratios diagram. In turn, the obtained Pb isotope data on the lherzolite xenoliths as well as that on paleooceanic complexes of Mongolia reveal the obvious difference of Pb isotope composition of the lithospheric mantle of the region from that of the Paleo-Asian ocean mantle. The observed difference can be explained by the metasomatic alteration of the suboceanic mantle during accretion and subduction processes before the EMVA and the GAVA formation. Thus, the conclusion about the key role of the metasomatized lithospheric mantle in the GAVA Late Cretaceous rocks formation can be made.

The study was supported by the RFBR (20-05-00401).

KEYWORDS: Eastern Mongolia, Gobi-Altai, Cretaceous volcanic rocks, lead isotope composition.
Mendeleev Rise basalts compile an acoustic basement of the North Chukchi Basin?
Authors: Startseva Kseniia , Nikishin Anatoly , Rodina Elizaveta
Published: March 2021

The Eastern Arctic is poor studied by offshore drilling. There are some wells drilled on the Alaska shelf, but Russian sedimentary basins are separated from Alaska basins by tectonic structures, therefore seismic complexes could not be traced confidently from Alaska to the North Chukchi Basin. Nevertheless, seismic lines in the Eastern Arctic acquired in last decade, samples from seafloor scarps on the Mendeleev Rise (Skolotnev et al., in preparation) and geologic data from adjacent onshore geology allows to assume the mechanisms and timing of the Eastern Arctic Basins forming. According to data from De-Longa Islands and from sampling on the scarps of the Mendeleev rise, the wide basalt volcanism was acting during ±125-100 Ma. The volcanism related to forming of rift basins all over the Eastern Arctic. On the seismic lines crossing the Mendeleev Rise some structures that could be interpreted as volcanos and Seaward Dipping Reflectors (SDR) are identified at the base of geological section. The top of these structures are traced on the seismic lines, and continue from the Mendeleev rise to the North Chukchi Basin where they are covered by clastic complexes that prograde from the territory of the Early Cretaceous Verkhoyansk-Chukotka Orogen. On this account the North Chukchi Basin started to form not earlier than in Barremian-Aptian. Continuation of Mendeleev Rise into the North Chukchi Basin is confirmed by the data of magnetic anomalies. To the south of the North Chukchi Basin on the Wrangel-Gerald High the volcanic build-ups and associated intrusions are interpreted. Presence of magmatic features in this area is confirmed on the magnetic anomaly map. The volcanic horizons lay below the sedimentary cover of the North Chukchi Basin. Our main conclusion is that Mendeleev Rise and North Chukchi Basin started to form nearly simultaneously during Aptian (Barremian) - Albian time and they compile connected geodynamic system.
A Package of New Universal Non-Iterative Parametrizations for Stable Surface Layer Transfer Coefficients of Momentum, Heat and Moisture in Numerical Earth System Models
Authors: Gryanik Vladimir , Luepkes Christof , Grachev Andrey , Sidorenko Dmitry
Published: March 2021

Results of weather forecast, present-day climate simulations and future climate projections depend among other factors on the interaction between the atmosphere and the underlying sea-ice, the land and the ocean. In numerical weather prediction and climate models some of these interactions are accounted for by transport coefficients describing turbulent exchange of momentum, heat and moisture. Currently used transfer coefficients have, however, large uncertainties in flow regimes being typical for cold nights and seasons, but especially in the polar regions. Furthermore, their determination is numerically complex. It is obvious that progress could be achieved when the transfer coefficients would be given by simple mathematical formulae in frames of an economic computational scheme. Such a new universal, so-called non-iterative parametrization scheme is derived for a package of transfer coefficients.

The derivation is based on the Monin-Obukhov similarity theory, which is over the years well accepted in the scientific community. The newly derived non-iterative scheme provides a basis for a cheap systematic study of the impact of near-surface turbulence and of the related transports of momentum, heat and moisture in NWP and climate models. 

We show that often used transfer coefficients like those of Louis et al. (1982) or of Cheng and Brutsaert (2005) can be applied at large stability only with some caution, keeping in mind that at large stability they significantly overestimate the transfer coefficient compared with most comprehensive measurements. The latter are best reproduced by Gryanik et al. (2020) functions, which are part of the package. We show that the new scheme is flexible, thus, new stability functions can be added to the package, if required.

 

 Gryanik, V.M., Lüpkes, C., Grachev, A., Sidorenko, D. (2020) New Modified and Extended Stability Functions for the Stable Boundary Layer based on SHEBA and Parametrizations of Bulk Transfer Coefficients for Climate Models, J. Atmos. Sci., 77, 2687-2716
The Ice, Cloud and Land Elevation Satellite-2 (ICESat-2): Mission Status, Science Results and Outlook
Authors: Magruder Lori , Neumann Tom , Kurtz Nathan
Published: March 2021

The Ice, Cloud, and Land Elevation Satellite-2 is well past its second year on orbit, and continues to collect high-quality measurements of the changing Cryosphere and beyond.  The Advanced Topographic Laser Altimeter System (ATLAS) has now emitted more than ~800 billion laser shots to support science associated with sea ice and the polar oceans, glaciers and ice sheets, the world’s forests, oceans, lakes and rivers in addition to vertical profiles of clouds and aerosols. The ATLAS lidar measurements provide elevations with horizontal and vertical accuracies of 10 m and 10 cm respectively. Analysis also reveals the required precision (~2 cm) needed to resolve sea ice freeboard. The data is a unique resource for derived products as well with contributions to global biomass estimations, ice sheet mass balance determination and inventories of our planet’s surface water stores. Recently, there have been many open source data tools released to the community to help with data inquires, access and analytics. These tools are important resources as the data volume continues to build.   In this presentation, we will provide an update on the operations and health of the observatory, review the many available data products served through the National Snow and Ice Data Center in the US, review new data tools available and highlight selected science results from the mission.  As of this writing, more than ~10 million data granules have been downloaded by ~2700 unique data users.  Recent science papers have documented the ongoing loss of mass from the Antarctic and Greenland ice sheets, the ability of ICESat-2 to measure the seasonal changes in sea ice freeboard and thickness throughout the year, and the potential for world-wide measurements of coastal bathymetry.  
'Unified' unstructured ocean, land and river modelling in the coastal zone
Authors: Engwirda Darren , Liao Chang , Zhou Tian , Bisht Gautam , Tan Zeli
Published: March 2021

The representation of coupled physical processes in coastal models is often constrained and simplified by details of the underlying numerical approach. Ocean, land and river dynamics are generally represented using different computational grids and numerical methods, and are not typically resolved at the fine spatial and temporal scales needed to capture coupled dynamics. In this work, we describe a new 'unified' approach to coupled ocean, land and river modelling, in which all components are represented on a common, multi-scale unstructured mesh, and employ compatible numerical formulations and coupling strategies. In contrast to conventional approaches, this unified approach does not rely on a hierarchy of nested sub-models, but rather leverages the flexibility of unstructured grids to seamlessly embed high-resolution domains within global model configurations. This initiative is an extension of the US Department of Energy's E3SM framework, designed to enhance the representation of coastal dynamics in global-scale ESMs. Initial work on a 'unified' representation of coastal environments is reported, focusing on the development of an unstructured model for the US mid-Atlantic coastal zone as part of the Integrated Coastal Modelling (ICoM) effort.
Declination magnetic charts for Mexico since 1907.0 to 2010.0
Authors: Paredes-Arriaga Alejandro , Caccavari-Garza Ana , Hernández-Quintero Esteban , Cifuentes-Nava Gerardo
Published: March 2021

We present the construction of magnetic declination charts corresponding to five epochs for last one hundred years; this was result of recovery and statistical analysis of historical magnetic data. The charts were made with the records of magnetic repeat stations reoccupation, distributed throughout the country, the goal was to observe and study the geomagnetic field morphology and their space-temporal variations in Mexico. We aimed to systematize an optimal numerical method for the spatial estimation to minimize the error given the average data for any Mexican magnetic chart: forty magnetic repeat stations and only one magnetic observatory. Also, the charts were compared with the original charts made in its corresponding epoch. The charts quality was improved and the historic geomagnetic information preserved, considering the invaluable record of historical magnetic measurements that exist in Mexico.
The potential and limitations of long-term fire regime reconstructions in Eastern Siberia based on sedimentary charcoal and low-temperature fire markers 
Authors: Dietze Elisabeth , Mangelsdorf Kai , Weise Jasmin , Matthes Heidrun , Lisovski Simeon , Herzschuh Ulrike
Published: March 2021

Forest fires are an important factor in the global carbon cycle and high latitude ecosystems. Eastern Siberian tundra, summergreen larch-dominated boreal forest on permafrost and evergreen boreal forest have characteristic fire regimes with varying fire intensities. Yet, it is unknown which role fire plays in long-term climate-vegetation-permafrost feedbacks and how high-latitude fire regimes and ecosystems will change in a warmer world. To learn from fire regime shifts during previous interglacials, prior to human presence, we use lake-sedimentary charcoal as proxy for high-intensity forest fires and monosaccharide anhydrides (i.e. levoglucosan, mannosan, galactosan: MA) as molecular proxies for low-temperature biomass burning, typical for surface fires in modern larch forest. However, MA pathways from source to sink and their stability in sediments are very poorly constrained. Recently, Dietze et al. (2020) found MA in up to 420 kyr old sediment of Lake El’gygytgyn (ICDP Site 5011-1), NE Siberia, suggesting that they are suitable proxies for fires in summergreen boreal forests. Surprisingly, the ratios of the MA isomers were exceptionally low compared to published emission ratios from modern combustions.

To understand what MA from Arctic lake sediments tell us, we have analyzed the MA and charcoal composition in modern lake surface sediments of Lake El’gygytgyn and three East Siberian lakes and we compare them to late glacial-to-interglacial El’gygytgyn records. The three Siberian lakes were chosen to represent spatial analogues to the El’gygytgyn conditions during MIS 5e and 11c. We discuss first results of the modern sediments in context of recent MODIS- and Landsat-based fire extents and biome-specific land cover data, a wind field modelling using climate data over eastern Siberia, and lake-catchment configurations from TDX-DEM analysis to assess potential fire proxy source areas and regional-to-local transport processes. Thereby, we provide insights into the meaning of sedimentary fire proxies, crucial for a sound reconstruction of long-term fire regime histories.
Alternatives to zircon in sedimentary provenance analysis: A case study in detrital garnet U-Pb and trace-element analysis
Authors: Mark Chris , Stutenbecker Laura , Andò Sergio , O'Sulivan Gary , Daly J. Stephen
Published: March 2021

Provenance analysis of clastic sediment is a powerful tool to track the evolution of hinterland tectonics and sediment routing systems, for which detrital U-Pb geochronology has proved a popular and rapidly-growing technique. However, >90% of published studies employ zircon (3,691/3,933 results for the keywords detrital geochronology; Clarivate Analytics Web of Science), a mineral which exhibits strong fertility bias towards felsic to intermediate igneous sources, and is rare in metamorphic settings in the absence of anatexis (e.g., Moecher & Samson, 2006). Thus, the development of complementary proxies is desirable. Garnet group minerals are particularly promising because garnet is dominantly formed in metamorphic settings and is a rock-forming mineral in several common metamorphic lithologies; it is thus typically abundant in clastic sediment sourced from orogenic terranes. Moreover, it can incorporate sufficient U to be dated in-situ by the U-Pb method (e.g., Millonig et al., 2020).

Here we focus on the Oligo-Miocene pro-foreland basin of the European Alps. Evolving from a distal marine to a fluvial-alluvial environment affected by at least one major marine incursion, the basin preserves a rich record of tectonic and climatic change in the hinterland. We report detrital garnet U-Pb and trace-element data acquired by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), which we integrate with compositional data obtained by energy- and wavelength-dispersive X-ray spectroscopy (Stutenbecker et al., 2019), and crystallographic data from Raman spectroscopy. We integrate these results with detrital apatite, rutile, and zircon U-Pb data, and discuss the implications for Alpine tectonics and drainage evolution, and future potential for detrital garnet U-Pb analysis.    

Millonig, L., et al., 2020. Earth Planet. Sci. Lett. 552, 116589, doi: 10.1016/j.epsl.2020.116589

Moecher, D., & Samson, S., 2006, Earth Planet. Sci. Lett. 247, 252–266, doi: 10.1016/j.epsl.2006.04.035

Stutenbecker, L., et al., 2019, Solid Earth 10, 1581–1595, doi: 10.5194/se-10-1581-2019
Soil moisture-atmosphere feedbacks mitigate declining water availability in drylands
Authors: Zhou Sha , Williams A. Park , Lintner Benjamin , Berg Alexis , Zhang Yao , Keenan Trevor , Cook Benjamin , Hagemann Stefan , Seneviratne Sonia , Gentine Pierre
Published: March 2021

Global warming alters surface water availability (precipitation minus evapotranspiration, P-E) and hence freshwater resources. However, the influence of land-atmosphere feedbacks on future P-E changes and the underlying mechanisms remain unclear. Here we demonstrate that soil moisture (SM) strongly impacts future P-E changes, especially in drylands, by regulating evapotranspiration and atmospheric moisture inflow. Using modeling and empirical approaches, we find a consistent negative SM feedback on P-E, which may offset ~60% of the decline in dryland P-E otherwise expected in the absence of SM feedbacks. The negative feedback is not caused by atmospheric thermodynamic responses to declining SM, but rather reduced SM, in addition to limiting evapotranspiration, regulates atmospheric circulation and vertical ascent to enhance moisture transport into drylands. This SM effect is a large source of uncertainty in projected dryland P-E changes, underscoring the need to better constrain future SM changes and improve representation of SM-atmosphere processes in models.
Design of Runge-Kutta based split-explicit time integration algorithms for the NEMO ocean model
Authors: Ducousso Nicolas , Lemarié Florian , Madec Gurvan , Debreu Laurent
Published: March 2021

The NEMO ocean model is currently based on the Leapfrog scheme that provides a good combination between simplicity and efficiency for low-resolution global simulations. However, this scheme is subject to difficulties that question its relevance at high-resolution : the necessary damping of its computational mode, e.g. via a Robert-Asselin filter, affect stability and increases amplitude and phase errors of the physical mode ; because it is unconditionally unstable for diffusive processes, monotonicity or positive-definiteness comes at a substantial cost and complication. The evolution toward a 2-level time stepping algorithm based on Runge-Kutta schemes is studied. Special attention is given to how to articulate a mode-splitting technique to handle the fast dynamics associated with the free surface. Linear stability analyses of several Runge-Kutta based, split-explicit algorithms are performed and the most promising ones are identified. They allow a good compromise between robustness, stability and accuracy for integration of internal gravity waves, Coriolis and advection processes. Idealized test-cases illustrate the benefits associated to the revised time-stepping compared to the original Leapfrog.
Mean amplitudes of the signal in the seasonal and shorter period length of day time series computed by the frequency-dependent autocovariance
Authors: Kosek Wieslaw
Published: March 2021

The frequency-dependent autocovariance (FDA) function is defined in this paper as the autocovariance function of a wideband oscillation filtered by the Fourier transform bandpass filter (FTBPF). It was shown that the FDA estimation is a useful algorithm to detect mean amplitudes of oscillations in a very noisy time series. In this paper the least-squares polynomial harmonic model was used to remove the trend, low frequency as well as the annual and semi-annual oscillations from the IERS eopc04R_IAU2000_daily length of day (LOD) time series to compute their residuals. Next, the mean amplitudes of the signal as a function of frequency were determined from the difference between the FDA of LOD residuals and FDA of power-law noise model similar to the noise present in LOD residuals.  Several power-law noise model data were generated with a similar spectral index and variance as the noise in LOD data to estimate the mean amplitude spectrum in the seasonal and shorter period frequency band.  It was shown that the mean amplitudes of the oscillations in LOD residuals are very small compared to the noise standard deviation and do not depend on the filter bandwidth of the FTBPF. These small amplitudes explain why LOD prediction errors increase rapidly with the prediction length.
Determining the particle-size distribution of soil materials with the integral suspension pressure (ISP) method – lessons learned from PARIO measurements
Authors: Durner Wolfgang , Alina Miller , Thomas Pertassek , Sascha C. Iden
Published: March 2021

The integral suspension pressure method (ISP) is an automated method to evaluate sedimentation experiments for particle size analysis of soil materials. In contrast to the traditional pipette and hydrometer methods, it is based on the continuous measurement of the suspension pressure at one depth in the sedimentation cylinder. The particle size distribution is determined by inverse simulation (Durner et al., 2017). The ISP is promising because it is semi-automated, continuous, based on process simulation, and does not hinge on oversimplifying assumptions. Most importantly, disturbance of the settling particles is minimized whereas disturbance is unavoidable when applying the traditional methods. ISP has been made commercially available by the METER Group AG (Munich) with a device called PARIOTM. This implementation of ISP leads to a computerized system which yields quasi-continuous particle-size distribution curves.

Practical experience with PARIO has shown that, despite cutting-edge pressure sensor technology with a resolution of 0.1 Pa, the accuracy of the particle-size analysis was less than expected from a theoretical analysis, and that the time required to determine the clay content exceeded theoretical expectations. In this contribution, we analyze the reasons for disturbances of the methodology in practical applications and show ways to improve accuracy by compensating different errors. Furthermore, we show how an extended version of ISP called ISP+, which considers a single additional measurement in the objective function (Durner and Iden, 2019), leads to stable estimates of the clay fraction while considerably reducing the measurement time.

References:

Durner, W., S.C. Iden, and G. von Unold (2017): The integral suspension pressure method (ISP) for precise particle-size analysis by gravitational sedimentation., Water Resources Research, 53, 33-48, doi:10.1002/2016WR019830.

Durner, W., and S.C. Iden: ISP+: improving the Integral Suspension Pressure method by an additional measurement, Geophysical Research Abstracts Vol. 21, EGU2019-12761, 2019.
SOC stabilization mechanisms and temperature sensitivity in old terraced soils
Authors: Zhao Pengzhi , J. Fallu Daniel , Cucchiaro Sara , Tarolli Paolo , Waddington Clive , Cockcroft David , Snape Lisa , Lang Andreas , Doetterl Sebastian , G. Brown Antony , Van Oost Kristof
Published: March 2021

Being the most common and widest spread man-made landform, terrace construction has resulted in an extensive perturbation of the land surface. Our mechanistic understanding of the underlying soil organic carbon (SOC) (de-)stabilization mechanisms and of the persistence of SOC stored in terraced soils, however, is far from complete. Here we explored the factors controlling SOC stability and temperature sensitivity (Q10) of heterotrophic soil respiration of abandoned prehistoric agricultural terrace soils in NE England. For this we combined soil fractionation and temperature sensitive incubation experiments under idealized, well-aerated topsoil conditions with measurements of terrace soil burial age. Results showed that a substantial part of the SOC stock in these terraced soils (43.5± 5.5%) was found in buried horizons. A significantly lower soil potential respiration was observed for buried terrace soils, relative to a control (non-terraced) profile. This suggests that the burial of soils is an important mechanism to slow down the decomposition of SOC in terraced soils. Furthermore, we observed a shift in the SOC pool composition from particulate organic C to mineral carbon mineral protected C with increasing burial age creating energetic barriers for microorganisms to overcome. This clear shift to more processed recalcitrant SOC with terrace soil burial age also contributes to SOC stability in terraced soils. Temperature sensitivity incubations revealed that as terraced and buried soil becomes older, lower C quality in buried horizons leads to an increase in temperature sensitivity of SOC. In conclusion, terracing in our study site has stabilized SOC as a result of soil burial during terrace construction with evolution to a more biologically processed SOC pool with increasing terrace soil burial age. These depth-age patterns of Q10 and SOC pool composition of terraced soils should be considered when assessing the effects of climate warming or terrace abandonment/removal on the terrestrial C cycle
How low-cost air pollution sensors could make homes smarter?
Authors: Omidvarborna Hamid , Kumar Prashant
Published: March 2021

The majority of people spend most of their time indoors, where they are exposed to indoor air pollutants. Indoor air pollution is ranked among the top ten largest global burden of a disease risk factor as well as the top five environmental public health risks, which could result in mortality and morbidity worldwide. The spent time in indoor environments has been recently elevated due to coronavirus disease 2019 (COVID-19) outbreak when the public are advised to stay in their place for longer hours per day to protect lives. This opens an opportunity to low-cost air pollution sensors in the real-time Spatio-temporal mapping of IAQ and monitors their concentration/exposure levels indoors. However, the optimum selection of low-cost sensors (LCSs) for certain indoor application is challenging due to diversity in the air pollution sensing device technologies. Making affordable sensing units composed of individual sensors capable of measuring indoor environmental parameters and pollutant concentration for indoor applications requires a diverse scientific and engineering knowledge, which is not yet established. The study aims to gather all these methodologies and technologies in one place, where it allows transforming typical homes into smart homes by specifically focusing on IAQ. This approach addresses the following questions: 1) which and what sensors are suitable for indoor networked application by considering their specifications and limitation, 2) where to deploy sensors to better capture Spatio-temporal mapping of indoor air pollutants, while the operation is optimum, 3) how to treat the collected data from the sensor network and make them ready for the subsequent analysis and 4) how to feed data to prediction models, and which models are best suited for indoors.
Cloud observations at THAAO Observatory during the Arctic YOPP 2020
Authors: Pace Giandomenico , Di Iorio Tatiana , di Sarra Alcide , Iaccarino Antonio , Meloni Daniela , Muscari Giovanni
Published: March 2021

The radiative effects of clouds and their microphysical structure in Polar regions are still object of large uncertainty, that contribute to determine the large inaccuracies of climate model in the representation of clouds and their effects.

In the frame of the CLouds And Radiation in the Arctic and Antarctica (CLARA2) project, a celiometer has been installed in November 2019 at the Thule High Arctic Atmospheric Observatory, THAAO, an international infrastructure located in proximity of Thule Air Base (76.5°N, 68.8°W), Greenland (http://www.thuleatmos-it.it/) with the aim of strengthening the cloud observational capability at the Observatory already including, among the other instruments, a microwave profiler and upward- and downward-looking pyranometers and pyrgeometers operating since July 2016.

CLARA2 should have contributed to the YOPP 2020 Arctic Special Observing Period (SOP) in February-March with intensive measurements of the atmospheric vertical structure by means of a microwave profiler, a celiometer and daily radiosoundings, but the arrival of the COVID19 prevented the involved researchers to carry out the field campaign at THAAO. Nonetheless the automatic measurements were collected regularly also during the 2020 SOP.

The temporal evolution of the cloud’s presence and characteristics during the two months SOP will be presented and discussed in terms of meteorological conditions, broadband surface radiation fluxes, cloud’s geometrical characteristics, phase and liquid water path.
Comparison between a six-year (2015-2020) continuous time series from an iGrav superconducting gravimeter and absolute gravity data at Mt. Etna volcano (Italy).
Authors: Greco Filippo , Carbone Daniele , Messina Alfio Alex , Contrafatto Danilo
Published: March 2021

Since September 2014, iGrav#016 superconducting gravimeter (SG; by GWR) has recorded continuously at the Serra La Nave Astrophysical Observatory (SLN; 1730 m elevation; ~6.5 km from the Etna’s summit craters; Italy).

Here we present results of a comparison between a six-year (2015-2020) time series from iGrav#16 and absolute gravity data collected through the Microg LaCoste FG5#238 absolute gravimeter (AG), in the framework of repeated measurements that were performed at the same installation site of the SG. Both AG and SG records have been corrected for the local tides, local atmospheric pressure and for the polar motion effect.

The comparison allows to estimate the long-term drift of the SG, defined as the total SG trend minus the observed trend in AG measurements, which is of the order of 9 microGal/year. Once the drift effect is removed,  there is a remarkably good fit between the two data sets. The differences between absolute gravity changes and corresponding relative data in the continuous time series from the SG are within 1-2 microGal (the total error on AG measurements at this station is typically +/- 3 microGal).

After being corrected for the effect of instrumental drift, the time series from the SG reveals gravity changes that are due to hydrological and volcanological effects.

Our study shows how the combination of repeated AG measurements and continuous gravity observations through SGs can be used to obtain a fuller and more accurate picture of the temporal characteristics of the studied processes.
Comparison of atmospheric vertical motion of three reanalysis datasets over Tibetan Plateau
Authors: Tian Rongxiang , Xu Jiayu
Published: March 2021

Vertical motion is an important feature of the atmosphere, being closely linked to clouds and precipitation. We present a comparison of the vertical velocity of air over Tibetan Plateau during the period 1981–2010 using three reanalysis datasets: ERA-Interim, JRA-55 and NCEP/NCAR. Statistical analysis methods were used to examine consistency between the datasets and their suitability in research and application in Tibetan Plateau. The results show that the vertical velocity fields from ERA-Interim and JRA-55 are more consistent than they are with those from NCEP/NCAR. The atmospheric vertical velocity fields from NCEP/NCAR lack details compared with those obtained from ERA-Interim and JRA-55. Use of ERA-Interim or JRA-55 may be preferable over NCEP/NCAR. The intensity of atmospheric vertical motion in the lower troposphere in JRA-55 is significantly higher than in ERA-Interim and NCEP/NCAR. In summer, the JRA-55 data are closest to the observed wind fields and the data stability best for the Tibetan Plateau region. Our results provide guidance for better application of reanalysis data and more accurate climate prediction for this region.
Geomorphic imprints of dynamic topography and intraplate tectonism in central Australia
Authors: Jansen John , Sandiford Mike , Fujioka Toshiyuki , Cohen Timothy , Struck Martin , Anderson Suzanne , Anderson Robert , Egholm David
Published: March 2021

The Finke River in central Australia is counted among the world’s oldest drainage systems, raising the prospect that it holds a geomorphic record relevant to testing ideas about the role of sub-lithospheric mantle flow in shaping the Australian landscape. The Finke’s upper reaches preserve an enigmatic set of intertwined active and relict gorges that suggest a complex history of incision, aggradation and re-incision. We measured cosmogenic 10Be and 26Al in fluvial gravels stored in the gorges, and we applied a Markov chain Monte Carlo-based inversion model to test two limiting-case hypotheses about the timing of the gravel deposition and exhumation. Our results suggest that the nuclide memory contained within the gravels was essentially erased during protracted sediment storage. Previous studies attribute landscape evolution to the intensified post-Miocene aridity in tune with the perception that central Australia experienced limited deformation during the Cenozoic. However, the close correlation between drainage network patterns and the gravity field leads us to propose, instead, that incision/aggradation phases in the upper Finke are driven by a flexural response (at ~102 km length scales) to extreme uncompensated loads embedded in the crust. Further, we suggest that dynamic mantle processes have deformed the central Australian topography over longer (~103 km) wavelengths via the in-situ stress field, with horizontal stress variations of order 1–10 MPa. Acting together, these crustal and sub-lithospheric structures have imposed to-and-fro tilting on the Finke, triggering the phases of incision/aggradation on a million-year timescale that created the unusual intertwined bedrock gorges. The amplitude of topographic responses in the upper Finke to inferred variations in end-loading on the plate helps resolve an ongoing debate about the effective elastic thickness of the central Australian lithosphere to no more than 35 km.
Flow and Stratification in a Bedrock Confined Estuary
Authors: Wild Amanda , Kwoll Eva
Published: March 2021

This research describes the impact of the bedrock island structure on the circulation and stratification of a macrotidal, partially mixed estuary in northwestern Canada (the Skeena River Estuary). Due to ongoing development in this formerly remote region, pressures have increased within the Skeena River Estuary over the past decade. However, there is still limited understanding of the estuary's morphodynamics due to its deviation from a 'typical' estuarine morphology. Located along an emergent, fjordal coastline, the Skeena Estuary River drains into a basin confined by bedrock and interrupted by multiple, irregular bedrock islands. Observations suggest that a subaqueous delta, associated facies, and the surface plume are split between several bedrock passages with limited information on the governing hydrodynamic processes. To overcome this, Acoustic Doppler current profiler cross-sectional transects and conductivity, temperature, depth, and turbidity profiles were taken in the nearshore (under 40 m) at locations across the estuary over two different (by ~1000 m3s-1) river stages. Over multiple dates with various river inflows, the tidal ratio to river inflow produces varied stratification patterns at a given site. During one point in time and river stage, bedrock passages are disproportionally exposed to marine and fluvial inflows, creating spatially diverse stratification patterns across the estuary. Stratification and passage morphology interactions determine the characteristics of tidal slack transitions, with horizontal and vertical separation occurring during well-mixed conditions and stratified conditions, respectively.
CLIMADA: an open-source climate risk assessment model. The latest developments!
Authors: Fairless Chris , Kropf Chahan , Bresch David
Published: March 2021

Do you want to translate your work on extreme weather into human and economic impacts? Do you want to investigate the statistical risk from climate change to your region, country or planet? Do you need to identify vulnerable populations and find the most effective climate adaptation measures?

The CLIMADA platform (CLIMate ADAptation) is built to support these analyses. The model is an open source, globally consistent, fully probabilistic risk assessment tool. It is designed with both academics and decision-makers in mind and is used in international financial planning, regional climate adaptation projects and impact forecasting.

CLIMADA combines hazard, vulnerability and exposure data to produce risk assessments, allowing you to supply any (or none) of the data required. The model includes event data for hazards including tropical storm wind and surge, windstorms, earthquake, flood, drought, wildfire and agricultural risk, at different stages of maturity. It includes the LitPop exposure model for estimating economic and population exposure, and impact/vulnerability functions to combine them with hazards. It is suitable for case studies and climate studies.

In this session we will present the model, highlight recent additions, and discuss our work supporting users in government, industry and the third sector. We want to hear questions from potential new users and collaborators and hope to spark conversations about new data sources, improved methodologies and integrations with other workflows.
Co-variation of silicate, carbonate, and sulphide weathering drives release of CO2 with erosion
Authors: Bufe Aaron , Hovius Niels , Emberson Robert , Rugenstein Jeremy K.C. , Galy Albert , Hassenruck-Gudipati Hima J. , Chang Jui-Ming
Published: March 2021

The supply of fresh minerals to Earth’s surface by erosion is thought to modulate global climate by removing atmospheric carbon dioxide (CO2) through silicate weathering. In turn, weathering of accessory carbonate and sulfide minerals is a geologically-relevant CO2 source, which may dampen or reverse the effect of silicate weathering on climate. Although these weathering pathways commonly operate side by side, we lack quantitative constraints on their co-evolution across erosion-rate gradients. Using stream-water chemistry across a 3 order-of-magnitude erosion-rate gradient in shales and sandstones of southern Taiwan, here, we demonstrate that silicate, sulfide, and carbonate weathering are linked: Increasing sulfide oxidation generates sulfuric acid and boosts carbonate solubility whereas silicate weathering kinetics remain constant or even decline, perhaps due to buffering of the pH by carbonates. On timescales shorter than marine sulfide compensation, CO2 emission rates from weathering in rapidly-eroding terrain are more than twice the CO2 sequestration rates in slow-eroding terrain. On longer timescales, CO2 emissions are compensated, but CO2 sequestration rates do not increase with erosion, in contrast to assumptions in carbon cycle models. We posit that these patterns are broadly applicable to many Cenozoic mountain ranges that expose dominantly siliciclastic metasediments.
Estimating root zone storage capacity from flux measurements
Authors: Giardina Francesco , Gentine Pierre , Konings Alexandra G. , Stocker Benjamin D.
Published: March 2021

Terrestrial evapotranspiration (ET) is a key factor in the global energy and water cycles. It is constrained by the transport of moisture from the soil and from vegetation to the atmosphere. The water storage capacity in the root zone (Sr) is an important parameter in land-atmosphere water exchanges, defining how long vegetation is able to transpire during drought. However, Sr is hard to measure directly, being associated with the depth of plant roots actively involved in water uptake and the potential of tap roots accessing deep water and enabling sustained transpiration during drought.

 

In this study, we present a method to estimate Sr from flux measurements, based on a deep neural network approach trained on eddy covariance (EC) data, multiple soil moisture datasets and a remotely sensed index of vegetation greenness. We derive a soil moisture stress function (fET) that isolates the control of soil moisture on ET. We then use EC data to estimate Sr by investigating how it relates to the climatology of the maximum cumulative water deficit (CWD, defined as the cumulative difference between actual ET and precipitation) experienced by the vegetation across different sites. We hypothesize that plants exposed to high CWD develop higher Sr (acclimation to water stress) and that maximum CWD is thus a good estimator of Sr. To identify root zone water storage from flux measurements, we regress the output of fET against CWD and estimate the maximum CWD for stress by calculating the intersection of the regression line with the x-axis. The apparent sensitivity of fET to CWD and its correlation with the maximum CWD across sites are indicative of adaptation to the prevailing climate and drought regime.

 

We find that for many sites, particularly in seasonally dry climates, fET does not exhibit a continuous decline with increasing CWD, but follows a step-change and levelling off. That is, at the high end of the CWD spectrum, fET no longer appears sensitive to further increases in CWD. This suggests that plants may have access to deep water reservoirs during the unfolding of a drought event, indicating that plant access to water becomes decoupled from water use.

 

This study highlights the need to investigate the representation of plant access to deep water reservoirs during drought in terrestrial ecosystem models. These findings could improve our understanding of land-climate interactions, particularly under water-limited conditions.
Airways
Authors: Kerr Vicki
Published: March 2021

Title: Airways

Author: Dr Vicki Kerr (Wintec, New Zealand)

Session: Exploring the Art-Science Interface

There is no other human activity that emits as much CO2 over such a short period of time as aviation, thereby significantly contributing to the acceleration of global warming, releasing carbon dioxide and other greenhouse gases into the atmosphere.

As an artist and former air traffic controller, I am interested in the profound impact of the air travel system on the natural environment and other species - as bodies on the ground and bodies in the air. Bodily movements are key in unearthing encounters and entanglements of animals and infrastructure, as a terrain of mobility-in-action that is normally difficult to portray or represent.  Most recently, due to the global spread of a coronavirus, worldwide air travel disruption has resulted in significant changes to the usual rhythm of flight, with humans effectively becoming de-centered and reconfigured within a broader ecological/multispecies system. 

My paper will discuss a recent collaboration between myself, a musician (Micah Livesay) and mathematician (Chris Batterton) that resulted in the creation of an immersive video/sound installation (Airways 2020), which aims to show the environmental impact of aviation and more broadly ways in which the atmosphere is permeated at every layer by technologies of communication, transportation and scientific research.  By using the mathematics of quantum wave superposition based upon aircraft movement data in New Zealand, the installation draws attention to the mathematical and statistical models playing essential roles in evaluating the effects of human activities, while also questioning and stretching the sensorium through animated renders and a musical score.  Drawing upon creative synergies between artistic and scientific thinking, ‘Airways’ reworks dynamic acoustic exchanges (humans and birds) alongside processes of calculation /computation to better our understanding of habitat connectivity and entanglements of species/human/non-human systems and networks.