bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptation and implementation of the coupled Regional Ocean Modelling System (ROMS) and the Los Alamos sea ice model (CICE) for Baltic Sea
Authors: Muzyka Maciej , Przyborska Anna , Eskandari Sobhan , Jakacki Jaromir
Published: March 2022

The Regional Ocean Modelling System (ROMS) coupled via Model Coupling Toolkit (MCT) with the Los Alamos sea ice model (CICE) is being prepared. The years 2016-2019 were successfully simulated on a 2.3 x 2.3 km grid with 30 sigma levels and atmospheric forcing delivered externally from data produced by Weather Research and Forecast Model (WRF). For long-term hindcast simulations it is assumed to use the other sources of atmospheric data such as reanalysis.

The latest work was focused on the creation of a new high resolution grid. Bathymetry with a resolution of 500 m was used, which was then filtered to meet the slope factor and so-called Haney number criteria. In this way, a grid with 40 sigma layers and a 2700x3200 horizontal number of nodes (which corresponds to a resolution of 0.25 NM) was created. In addition, interpolation of forcing data was introduced to save disk space. Relevant pieces of code have been added to both ROMS and CICE that made possibility of delivering atmospheric data on 600x640 grid which is almost 23 times smaller than model grid.

In the future it is planned to work on the CICE model for improving its compatibility with satellite data. In particular, it will be interesting to compare the ice deformations available from the model output with those calculated from consecutive satellite images. Another important aspect of the CICE model appears to have the correct fast ice representation in simulations. In the case of the Baltic Sea, a particularly important area for this phenomenon is the Bay of Bothnia. Preliminary simulations show that CICE underestimates the area covered by fast ice and thus the problem need to be better studied.

Calculations were carried out at the Academic Computer Centre in Gdańsk. 
Emissions consistent with halting global warming
Authors: Allen Myles , Jenkins Stuart , Froelicher Thomas , Friedlingstein Pierre
Published: March 2022

The IPCC Special Report on 1.5°C (SR1.5)[i] stated “Reaching and sustaining net-zero global anthropogenic CO2 emissions and declining net non-CO2 radiative forcing would halt anthropogenic global warming on multi-decadal timescales (high confidence)”, implying that net zero CO2 emissions and declining non-CO2 forcing was a sufficient condition for any ongoing global warming to be indistinguishable from natural climate variability on interdecadal timescales. The IPCC 6th Assessment Report (AR6)[ii] went much further: “limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions”, implying that net-zero CO2 emissions was a necessary condition for reducing the ongoing rate of global warming to zero. We discuss interpretations of these statements in the context of a policy environment focussed on the coming century, rather than multi-century timescales. We show that two quantities are important in determining the CO2 emissions and non-CO2 forcing consistent with halting global warming: the Rate of Adjustment to Constant Forcing (RACF), or the fraction rate of global warming over the decades following forcing stabilisation, and the Rate of Adjustment to Zero Emissions (RAZE), or the RACF minus the centennial rate of CO2 forcing decline after CO2 emissions reach net zero. We use results from the Zero Emissions Commitment Model Intercomparison Project to show that the best-estimate value of the RAZE is close to zero, possibly negative at low warming levels, with a range of uncertainty that straddles zero. Hence the evidence currently available suggests only that achieving net zero or net negative CO2 emissions is as likely as not required to halt CO2-induced warming on interdecadal timescales. That said, it is virtually certain that any residual emission consistent with no further warming would be an order of magnitude lower than current emission rates and within the uncertainty of CO2 sources and sinks in the second half of this century.

[i] Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, et al: Global Warming of 1.5°C, IPCC, 2018

[ii] IPCC, 2021: Summary for Policymakers. In: Climate Change 2021, the Physical Science Basis [Masson-Delmotte, V., P. Zhai, et al (eds.)]. Cambridge University Press (2021).
The sodium exosphere of Mercury and its dynamics
Authors: Mangano Valeria
Published: March 2022

The exosphere is the upper layer of a planetary atmosphere, and the last planetary territory before the interplanetary medium. In case of planets without a proper atmosphere, as Mercury, the exosphere is also the only kind of ‘atmosphere’ the planet possesses, and it is directly in contact with the surface. Due to this peculiarity, its origin is mainly from the surface outgassing, through a complex series of processes that acts as sources. The exospheric composition is then strictly related to the planet surface, but also to the other many interactions that the exosphere experiences with: the solar wind radiation and particles, the intrinsic magnetic field and ions circulation, the interplanetary magnetic field, the (micro)meteoritic bombardment. In addition, the interaction with the previously cited elements may also cause depletion. As a consequence, the exosphere of Mercury experiences an intense spatial and temporal variability.

The resulting dynamics of the exosphere of Mercury is evidenced in the studies of the sodium component that is a perfect tracer of the hidden interactions with the surrounding environment.

MESSENGER mission in the last decade highlighted the strong interchange with the intrinsic magnetic field, and the Earth-based observations with the interplanetary magnetic field. In the next future, the BepiColombo mission to Mercury, launched in October 2018, with its instrumentation devoted to the study of the magnetic field, ions and neutral particles will contribute to a comprehensive explanation of the processes and interactions that generate, sustain and change it.

 
Cloud droplet number susceptibility to CCN concentrations in low level boundary layer clouds: comparison of in-situ observations and large-scale models
Authors: Virtanen Annele , Joutsensaari Jorma , Kokkola Harri , Seland Øyvind , Zieger Paul , Karlsson Linn , Riipinen Ilona , Krejci Radovan , Hyvärinen Antti , Lihavainen Heikki , Romakkaniemi Sami
Published: March 2022

The susceptibility of cloud droplet number concentration (CDNC) to cloud condensation nuclei (CCN) number concentration is one of the major factors controlling the aerosol indirect forcing. In this study we investigate the sensitivity of CDNC to CCN concentrations using long term in-situ observations from three stations (Puijo, Pallas, Zeppelin) locating in Finland and Arctic. These stations represent semiurban, remote and Arctic remote environments with differences in typical updraft velocity conditions as well as in aerosol number concentrations. We compare the in-situ observations with three large scale models (ECHAM-M7, ECHAM-SALSA and NorESM) having differences in aerosol presentation while the activation parametrization is the same in all three model setups. In the comparison we use CDNC and CCN model outputs of the gridbox corresponding to the location and the height for each station. In addition, we compare the updraft velocities from the models and stations when they are available. Our current observational results show very high susceptibility of CDNC and CCN in all investigated stations. The agreement between the large scale models and observations was very good for Puijo and Pallas stations, but for the Arctic station (Zeppelin) the modelled CDNC susceptibility to CCN was much lower than the observed. This might be related to the recent results demonstrating that Aitken mode particles can active to cloud droplets at Zeppelin station (Bulatovic et al., 2021; Karlsson et al., 2021). In addition, at Zeppelin CDNC exhibits very low values which are below the lower bound imposed by ECHAM.

References:

Bulatovic, I., Igel, A. L., Leck, C., Heintzenberg, J., Riipinen, I., and Ekman, A. M. L.: The importance of Aitken mode aerosol particles for cloud sustenance in the summertime high Arctic – a simulation study supported by observational data, Atmos. Chem. Phys., 21, 3871–3897, https://doi.org/10.5194/acp-21-3871-2021, 2021.

Karlsson, L., Krejci, R., Koike, M., Ebell, K., and Zieger, P.: A long-term study of cloud residuals from low-level Arctic clouds, Atmos. Chem. Phys., 21, 8933–8959, 2021.
Is thallium in peat a good indicator of anthropogenic contamination?  Examples from Czech sites with contrasting pollution histories.
Authors: Mihaljevic Martin , Ettler Vojtech , Vanek Ales
Published: March 2022

The purpose of this study is to describe the Tl distribution and accumulation rates in Czech peat soils with contrasting anthropogenic loads. Nine peat cores were sampled in the mountain areas of the Czech Republic (6 cores in the northern part affected by emissions from coal-burning power plants and 3 in the pristine southern part). In addition, 3 cores were collected close to the Pb mining and smelting area of Pribram. Cores were 210-Pb dated and trace metals/metalloids were measured in the digests by ICP-MS. Maximum Tl concentrations in peat were significantly higher in the polluted northern areas (1.16 mg/kg) and close to the Pb smelter (0.83 mg/kg) than in the pristine area (0.45 mg/kg). Thallium distribution well correlated with other metals (Pb, Hg) and metalloids (As, Sb). Thallium enrichment factors (EFs) calculated against Sc reached the maximum value of 17 indicating significant input of anthropogenic Tl. Thallium accumulation rates in peat varied between 20 and 50 µg/m2/y until 1930s, followed by a significant increase related to industrial activities in the northern part of the Czech Republic (up to 290 µg/m2/y in 1980s). In contrast, maximum Tl accumulation rate at the pristine site was 88 µg/m2/y. Data from the vicinity of Pb mines/smelter indicated higher accumulation rates even in the second half of the 19th century (between 50 and 200 µg/m2/y) followed by a significant decrease in late 1970s as a result of more efficient flue gas cleaning technology installed in the smelter during this period. 
Assessing the impact of urbanization on urban evapotranspiration and its components using a novel four-source energy balance model
Authors: Chan Han , Huang Jinhui , Li Han , Wei Yizhao
Published: March 2022

Urbanization substantially changes many aspects including the regional hydrological cycle, energy balance, and microclimate. However, the degree to which urbanization alters urban evapotranspiration (ET) and its components (soil evaporation (E), vegetation transpiration (T), impervious surface evaporation (I) and water body evaporation (W)) remains unclear. A significant obstacle is the absence of a multi-source energy balance model for an urban area. To solve this issue, a customized four-source energy balance model for urban areas (FSU model) is proposed that differentiates between urban E, T, W, and I. The performance of the FSU model was verified using the eddy correlation (EC), stable hydrogen and oxygen isotope observations in a mega city: Tianjin, China. Long-term urban ET and its composition changes were reconstructed using the Landsat image during the period of 1986-2021 in Tianjin. Trend analyses demonstrate that urban ET, E, and T exhibit significant decreases of trend, while urban W, sensible heat flux (H), and Bowen ratio (BR) exhibit significant increases in trends with urbanization. Urban ET decreased at a rate of 1.41 mm/yr, corresponding to a ~ 13% decrease below the long-term mean value of total urban ET during the period 1986-2021. Correlation analyses revealed a declining trend of urban ET, E, and T primarily caused by urban land use changes, while the increasing trends of urban W, H, and BR were mainly due to the urban microclimate changes. The proposed FSU model aids in assessment of the urban heat island (UHI) effect and facilitates scientific water resources management in urban areas. This research improves the in-depth understanding of the impact of urbanization on urban ET and its components.
Diagenetic carbonates from deep sub-seafloor organic-rich sediments influenced by magmatic sill intrusions (IODP Exp 385-Guaymas Basin, Gulf of California)
Authors: Gontharet Swanne , Pierre Catherine , Pelleter Ewan , Caquineau Sandrine , Boudouma Omar , Demange Jérôme , Teske Andreas  P. , Lizarralde Daniel , Höfig Tobias W. ,   Expedition 385 Scientists
Published: March 2022

   During the International Ocean Discovery Program (IODP) Expedition 385, diagenetic carbonates were recovered at different depths (from 10 to 534 mbsf) in six drilling sites (U1545, U1546, U1547, U1548, U1550 and U1552) distributed from the northern spreading segment of the Guaymas Basin (Gulf of California) to ~52 km away from the axial graben. As this basin is a site of active sea floor spreading, hemipelagic diatomaceous and organic-rich sediments rapidly accumulating at all these drilling sites are influenced by magmatic intrusions, at depths greater than 90 mbsf. The geothermal gradient observed ranges from 135 °C/km to 682 °C/km. Except in sites U1547 and U1548, both located close to a circular hydrothermal mound (called Ringvent), sills are in thermal equilibrium with the surrounding sediments.

   Carbonate samples (over fifty) collected during this expedition are composed of fine-grained micritic sediments and weakly to strongly lithified carbonate concretions. The petrographic observations and XRD analyses show that stoichiometric dolomite is the dominant authigenic carbonate phase, with minor contribution of Fe-rich dolomite, and low- to high-Mg calcite. Centimeter-sized concretions composed of ankerite and Mg-calcite also occur in the sediments collected from the northern axial graben (site U1550) and a site with subsurface gas hydrates (U1552), respectively. Other authigenic minerals are often associated with these carbonates including pyrite, barite, anhydrite, zeolites and crystalline opal (opal-CT). The carbon isotopic compositions of the bulk carbonate from these samples exhibit large variations ranging from -28.9 to +12.0‰ VPDB. Very low d 13C values, only measured in a centimetre-seized concretion associated with cold methane seepage (site U1552), indicate that the bicarbonate used for carbonate precipitation is derived from anaerobic oxidation of methane (AOM) coupled with bacterial sulfate reduction (BSR). The very high d13C values of diagenetic carbonates indicate the use of biogenic 13C-rich CO2 reservoirs related to active methanogenesis or other autotrophic microbial pathways. The oxygen isotopic compositions of these carbonates cover a large range from -5.3 to +4.0‰ VPDB. The decreasing d18O values with increasing depth reflect the effect of high geothermal gradients due to the close proximity of magmatic sills.  
Extreme heatwaves in Europe 1950-2020: analysis of the links between meteorology, population, and impacts
Authors: Mandonnet Théo , Jézéquel Aglaé , D'Andrea Fabio , Vallet Améline , Guivarch Céline
Published: March 2022

There is high confidence that heatwaves will become more frequent and more intense under the influence of climate change. Different definitions of heatwaves exist based on the statistical distribution of temperature, in general using thresholds and duration and extension criteria.
If one observes the overlap between these definitions and the actual human and material damage produced by heatwaves, it appears that there is low consistency between the two. In other terms, a large amplitude heatwave in the physical climatological sense may not be equivalently as large in terms of impacts.
By crossing meteorological (E-OBS), demographic (WorldPop, GHS-POP), and impact (EM-DAT) databases at the European scale, we developed indices to classify heatwaves and select extreme ones in terms of impacts. We also proposed a method to evaluate the classification abilities of these indices. Including demographic data in the indices seems central to understand the links between meteorological conditions and observed impacts.
Is Amazon deforestation decreasing the number of thunderstorms over Tropical America?
Authors: Price Colin , Bekenstein Raam , Mareev Evgeny
Published: March 2022

Lightning activity is predicted to increase with global warming, though estimates of lightning sensitivity to a change of temperature vary widely.  Since lightning is a small scale process, it must be represented by parameterizations in climate models. This paper uses large-scale meteorological parameters tied to thunderstorm generation to improve existing empirical models that simulate regional thunderstorm behavior. This study focuses on Tropical America, and uses the ERA5 higher resolution reanalysis data (ERA5) to develop our empirical model.  Thunderstorm data were taken from the World Wide Lightning Location Network (WWLLN) and processed using the clustering algorithm developed by Mezuman et al. (2014). The two meteorological parameters that correlated best with thunderstorm clusters in Tropical America were specific humidity (SH) and convective available potential energy (CAPE).  The resulting empirical model was run from 1979-2019 using ERA5 reanalysis data as input. This approach enables the observation of long-term trends in the behavior of thunderstorms in the regions, in the absence of a complete historical lightning record. To our surprise, Tropical American thunderstorms exhibited a negative trend over this period, with a ~8% decrease in thunderstorm clusters since the 1980s even with a rise of 1K in temperature over the same period. The regions of largest decreases in thunderstorm activity align well with estimates of deforestation.  We estimate that for every 1 Tg C lost due to deforestation, there is a 10% decrease in thunderstorm number.
Bathymetry changes due to delayed basal ice melt at the proglacial lake Obersulzbachsee, Hohe Tauern, Austria – Implications for sediment budgeting
Authors: Otto Jan-Christoph , Heine Erwin
Published: March 2022

Recent glacier lake formation in mountain areas is a consequence of temperature increase and subsequent glacier melt. These new lakes affect the sediment cascade by collecting great parts of the sediment input by the meltwater streams. A quantification of these trapped sediments can be achieved by assessing changes in the lake bottom surface at different periods in time. Bathymetry changes can be affected by the delayed melting of buried glacier ice, preserved at the lake floor, which lead to an overestimation of sediment volumes.

We analysed bathymetry changes within the proglacial lake Obersulzbach, Hohe Tauern range, Austria over a period of 13 years. Lake floor and delta sediments were investigated using high resolution, multi-temporal geophysical data derived from sub bottom profiling (SBB), echo sounding and ground penetrating radar (GPR). We compared three instances of bathymetry data that document changes of the lake floor attributed to ice melt and sedimentation. SBB and GPR data were applied to detect buried ice underneath the sediments in order to assess the sediment and the ice volume in the lake and delta. 

The proglacial lake Obersulzbach formed in 1998 when the tongue of the Obersulzbach glacier in the Hohe Tauern Range, Austrian Alps, retreated behind a bedrock barrier. The glacier lake evolved in a former confluence zone of four glacier parts that originate in the valley head of the Obersulzbach valley. The lake has a maximum depth of 40 meters and a size of 170,000 m². The glacier ice retreated from the lake area in 2010 to a distance of more than 500 meters from the lake in 2021. Since 2009, a delta started to build up at the distal part of the lake fed by two meltwater streams. Parts of the delta started to sink below lake level in 2019, forming localised depressions. This process continued in 2020 and 2021 when large parts of the delta sunk into the lake increasing the lake area by 30%. In the delta area, the surface sunk by up to 20 m within 2 years. We attribute these changes to a delayed, but rapid melting of buried glacier ice at the lake floor and within the delta more than 10 years after the retreat of the glacier tongue.
Storing CO2 in Geothermal Reservoir Rocks: A Laboratory Study on Acoustic and Mechanical Properties
Authors: Janssen Martijn , Redondo Garcia Elara , Barnhoorn Auke , Draganov Deyan , Wolf Karl-Heinz
Published: March 2022

This work is conducted within the framework of SUCCEED, a research consortium with the aim to validate the utilization of produced CO2, from the Hellisheiði geothermal plant in Iceland, for re-injection into the field for: i) pressure maintenance, and thus promoting geothermal production, and ii) permanent storage in basaltic formations through CO2 mineralisation. The objective of work carried out at Hellisheiði in SUCCEED is to provide a state-of-the-art, cost-effective, and low-environmental impact coupled geothermal-CO2 storage monitoring technique. In this work, a detailed seismic-velocity and mechanical behaviour-characterisation study was carried out on various rock formations present at the outcrops near the Hellisheiði geothermal site.

Laboratory experiments include well-controlled active-source acoustic-assisted unconfined (UCS) and confined (CCS) compressive strength tests. Where the former, i.e., UCS, allow for investigating the mechanical behaviour, or static elastic properties, of the assessed rock formations, the latter, i.e., CCS, shed light on the seismic velocities at field-representative stress conditions (up to 70 MPa). The abovementioned experiments were conducted at ambient temperature and at dry pore-space conditions. For studying pore-scale phenomena (e.g., number of connected pores, mineralogy, etc.), several thin sections were prepared and micro computed tomography (micro-CT) scans were taken.

The studied rock formations included basalts with varying porosities (ranging from 22 to 51 %), i.e., the main reservoir formation, hyaloclastites, and dykes. Micro-CT scan analyses, conducted on the basaltic reservoir formation in Hellisheiði, revealed that its pore structure is highly heterogeneous. Active-source acoustic-assisted UCS tests showed similar velocity – stress trends: a rapid increase in velocity at low stress levels, related to closure of potential microcracks (and thus compaction), followed by a more modest increase at higher levels of axial stress. The pyroclastic hyaloclastite appeared to be the weakest material assessed, revealing relatively low seismic velocities, a static Young modulus of 2.54±0.09 GPa, and an ultimate strength of around 4.3 MPa. On the contrary, the igneous intrusion, i.e., dyke, is by far the stiffest material studied, yielding a Young modulus of 34.85±0.39 GPa and an ultimate strength of more than 200 MPa. The investigated basalt samples indicated a porosity-dependent Young modulus and compressional-wave velocity, where both the modulus and velocity decrease significantly with increasing (connected) porosity following a power-law function.   
Drought-flood transitions across different hydro-climates
Authors: Götte Jonas , Brunner Manuela Irene
Published: March 2022

Drought-flood transitions greatly challenge water management and the development of adaption measures to extreme events. These transitions can occur rapidly but may also take many months or years and are often studied using climate instead of streamflow data – neglecting the role of surface processes. The time between one extreme and the other may depend on climate and catchment characteristics including topography, soil types and water use. However, it is yet unclear how drought-flood transition times vary regionally in dependence of climate characteristics, flow processes, and water storage.
In this study, we analyse how drought-flood transition times vary across different hydro-climatic zones. We show how transition times, i.e. the number of days between drought-termination and the following flood event, vary in space. We identify indicators and common patterns of rapid transitions by correlating drought and flood characteristics to transition times. To do so, we use large-sample datasets such as CAMELS and LamaH, which provide diverse catchment characteristics in addition to streamflow data. This information helps to identify catchments with a high likelihood of abrupt drought-flood transitions. Such identification is highly relevant because flood preparedness is often low during drought events, which potentially increases the severity of flood impacts.
Fluid migration, deep dehydration, and melt generation in the Lesser Antilles subduction zone
Authors: Bie Lidong , Hicks Stephen , Rietbrock Andreas , Goes Saskia , Collier Jenny , Rychert Catherine , Harmon Nicholas , Maunder Benjamin ,   VoiLA Consortium
Published: March 2022

Volatiles play a pivotal role in subduction zones dynamics, associated geological hazards and mineralization, yet their pathways remain partially understood. The Lesser Antilles subduction zone can yield insights to volatile recycling as a global end-member, where old oceanic lithosphere formed by slow spreading slowly subducts. Here we use seismograms from local earthquakes recorded by a temporary deployment of ocean-bottom seismometers in the fore- and back-arc during the VoiLA (Volatile Recycling in the Lesser Antilles) experiment to characterize the 3-D properties of the slab, back-arc and mantle wedge in the north-central Lesser Antilles subduction zone. Along the top of the slab, defined by the underlying Wadati-Benioff seismicity, we find low P-wave velocity extending to 130–150 km depth, deeper than expected for magmatic oceanic crust. The deep low velocities together with high Vp/Vs at 60–80 km and 120–150 km depth are consistent with a significantly tectonised and serpentinised slab top, as expected for lithosphere formed by slow spreading. The most prominent high Vp/Vs anomalies in the slab correlates with two projected fracture zones and the obliquely subducting boundary between Proto-Caribbean and Equatorial Atlantic lithosphere, indicating these structures enhance hydration of the oceanic lithosphere and subsequent dehydration when subducted. Deep dehydration of slab mantle serpentinite is evidenced by high Vp/Vs anomalies in the back-arc offshore Guadeloupe and Dominica. Right above the slab, the asthenospheric mantle wedge is imaged beneath the back-arc as high Vp/Vs and moderate Vp feature, indicative for fluids rising from the slab through the overlaying cold boundary layer. The fluids might be dragged down with the subducting slab before rising upwards to induce melting further to the west. The variation in seismic properties along the subducting slab and in the back-arc mantle wedge shows that the changes in hydration of the incoming plate govern the dehydration processes at depth. The highest Vp/Vs anomaly in the back-arc west of Dominica at depth greater than 120 km, together with the anomaly at 60–80 km depth on the slab east of the island, appear to track the source and path of excess volatiles that may explain the relatively high magmatic output observed on the north-central islands of the Lesser Antilles arc.
The applicability of automated static image analysis to identify sedimentary environments
Authors: Gresina Fruzsina , Farkas Beáta , Fábián Szabolcs Ákos , Szalai Zoltán , Varga György
Published: March 2022

The granulometric (particle size and shape) data of sediments provide insights into the processes of grain formation, transport, deposition, and post-depositional alteration mechanisms. Therefore, granulometric proxies are widely used in paleogeographical research.

A statistically robust, objective, and representative description of the particle size and shape characteristic of a sample can only be achieved with a large number (n>104-5) of observed mineral grains. Automated image analysis techniques meet the above requirements. Not only the size distributions of the scanned particle populations are determined, but also the distributions of different shape (e.g., circularity, convexity, solidity) and other shape-dependent size parameters (e.g., circular equivalent diameter, length, width, circumference, area) of each grain.

The presented granulometric analyses were based on sediments from the Carpathian Basin (Central Europe): filling material from Pleistocene periglacial sand wedges (Kemeneshát, Mogyoród gravel pit –Danubian Plain), recent wind-blown sand (Nyírség, Danube-Tisza Midland Ridge), fluvial sand from floodplain and transport media (Lower-Tisza Plain and Dráva Plain). The grains were analysed primarily for their circularity, solidity, and convexity properties. Our aim was to identify fingerprints related to the environment and the transport processes (e.g., type, time).

According to our granulometric results, the Kemeneshát and the Mogyoród site sand wedges can be distinguished. Most samples from Kemeneshát contained fresh, less rounded grains while the other source contained mature, rounded grains. Although, it was also possible to differentiate between the Kemeneshát samples based on the grain shape parameters. Granulometric differences can be detected between the fluvial and eolian sand samples, especially in the case of roundness parameters. Using granulometric proxies, it can be concluded that the filling material of the wedges in the Mogyoród gravel pit is mainly eolian. Therefore, the origin of Kemeneshát samples cannot be clearly identified due to the less mature nature of the grains. Examination of more samples is required to reveal granulometric fingerprints that characterise certain sedimentary environments.

The application of granulometric proxies on relict and recent sand materials can be used to reconstruct the paleoenvironmental conditions. The method can be a new tool for investigating the origin of different sediments and can extend the interpretation of granulometric data.
Support of the National Research, Development and Innovation Office (Hungary) under contract NKFIH FK138692 is gratefully acknowledged.
Evaluation of precipitation reanalysis products in space and time for ungauged sites in Slovenia
Authors: Müller-Thomy Hannes , Nistahl Patrick , Bezak Nejc , Alexopoulos Marcos
Published: March 2022

Precipitation reanalysis products (PRP) are a promising data source for ungauged regions. Since observed time series are often i) too short, ii) their temporal resolution is not sufficient or iii) the network density is too low, they cannot be used as e.g. input for rainfall-runoff (r-r) modelling and derived flood frequency analysis. Reanalysis products as global simulation of the atmosphere over the last decades solve the aforementioned issues.

From the latest PRP three are most promising due to their spatial and temporal resolution for r-r modelling of small to mesoscale catchments: ERA5-Land (raster with approx. 9 km width), REA6 (6 km) and CFSv2 (22 km). These three PRP are able to cope with the dynamics of the r-r process due to their hourly resolution. The PRP are evaluated for Slovenia (Europe) with both, precipitation characteristics in space and time, and runoff characteristics. For areal precipitation, continuous and event-based characteristics are evaluated as well as precipitation extreme values. Simple correction methods for identified biases are suggested and applied. It can be seen that although the PRP clearly differ from each other, there is no clear ‘favourite’ to use as input for the r-r modelling.

To conclude about the suitability of the PRP for r-r modelling, continuous simulations are carried out with GR4H for 20 catchments in Slovenia (55 km²-480 km²). Models are re-calibrated for each PRP input based on KGE. Simulation results of calibration and validation period are evaluated by runoff extreme values, KGE, flow duration curve and intra-annual cycle. Interestingly, first results show that the deviations of some rainfall characteristics do not necessarily transfer to deviations in runoff characteristics, which can be explained by the high nonlinearity of the r-r process. PRP lead to better, at least similar results for runoff characteristics for catchments without rain gauges in their centre.
Effects of tillage systems on soil water distribution, crop development, and transpiration of soybean.
Authors: Liebhard Gunther , Klik Andreas , Neugschwandtner Reinhard W. , Nolz Reinhard
Published: March 2022

Tillage practices are known to affect soil water retention, plant available water and, consequently, crop production. Therefore, adjusted and sustainable tillage practices may contribute to an efficient use of limited available water resources. Impacts of tillage can be determined by assessing soil hydraulic properties and crop characteristics. In this study, three tillage practices were investigated with respect to soil water distribution and crop development, with a specific focus on determining actual evapotranspiration (ET) and crop transpiration (T). T/ET ratios should give additional information on soil water availability and crop water use. The practices included conventional tillage, reduced tillage (no plow), and no-tillage and were investigated on a long-term rainfed field experiment with soybean (glycine max l. merr) planting. The long-term experimental field is located in Raasdorf in the agricultural region Marchfeld east of Vienna, Austria (48°14’ N, 16°35’ E; 156 m elevation a.s.l., average annual precipitation of approx. 497 mm). The field is separated in experimental plots of 960 or 1,440 m2. The measurements comprised automated monitoring of weather and soil water by means of a telemetric sensor network as well as manual monitoring of crop development. ET and its components were determined using an isotope-based water balance technique. ET rates were determined at the conventional experimental plot based on a water balance and verified with scintillometer measurements on a nearby field of 11.5 ha. In the researched vegetation period with limited water availability, the conservative tillage practices showed better water storage, water use, and crop yields compared to the conventional practice. The weekly T/ET ratios progressed according to the canopy development, which was affected by the tillage-induced soil conditions. In this context, delayed plant development – specifically at the no-till plots – led to extended green cover and productive water use during the late season, where a large part of the precipitation has fallen. The tillage-induced difference of wetness at soil surface, however, did not have a substantial effect on T/ET; even soil evaporation was similar at all plots. Furthermore, the ratios showed the beneficial effect of mulch protection regarding unproductive losses by evaporation, in particular during the initial periods of crop emergence and development. Thus, the assessment of T/ET ratios improved the insights in impacts of management practices and showed potential to promote the efficient use of the available water resources.
Weak effectiveness on vegetation greenness, cover and productivity at the edges of protected areas on the Tibetan Plateau, China
Authors: Hua Ting , Zhao Wenwu , Cherubini Francesco , Hu Xiangping , Pereira Paulo
Published: March 2022

Protected areas (PAs) are the critical societal tool to preserve global vegetation growth, but growing evidence showed the effectiveness of PAs varied in different regions. Furthermore, recent efforts to quantify conservation efficiency have primarily focused on vegetation coverage, thereby ignoring conservation efficiency’s comprehensive recognition of vegetation greenness, cover, and productivity. Here, based on satellite observation and windows search strategy, we measured the conservation efficiency at the edge of PAs on vegetation greenness, cover, and productivity on the Tibetan Plateau. The results showed that PAs’ edge performed a weak but significant role in vegetation growth. PAs had a noticeable opposite effect on greenness, cover, and productivity in 10.52 percent of the samples. Fragmented landscapes and landforms are more likely to impede conservation efficiency than geography background factors. This work comprehensively identified the conservation efficiency of vegetation at the edges of PAs, and these findings can help optimize the design of PAs and prevent vegetation losses.
SDR (Seaward Dipping Reflectors) mapping in the Amerasia Basin
Authors: Rodina Elizaveta , Nikishin Anatoly , Startseva Ksenia
Published: March 2022

Study area includes Alpha-Mendeleev Rise and contiguous deep-water basins – Toll, Mendeleev, Nautilus and Stefansson Basins near the eastern slope and Podvodnikov and Makarov Basins near the western slope. The western boundary is Lomonosov Ridge; the eastern boundary is Chukchi Plateau and part of the Canada Basin. There are Chukchi and East Siberian Seas on the continental shelf.

Within the study area, we studied and interpreted seismic 2D profiles from the Russian Arktika-2011, Arktika-2012, Arktika -2014, and Arktika-2020 expeditions. We also worked with open Canadian seismic data (Shimeld et al., 2021) and published data (e.g., Ilhan, Coakley, 2018). A unified seismostratigraphic correlation was carried out for the entire region.

Many half-grabens locate on the edges of deep-sea basins. Bright-amplitude reflectors with wedge-shaped architecture fill half-grabens. These reflectors are similar to SDR and they represent by interbedding of basaltic lavas and sedimentary rocks. They are typical for the synrift complex within the study area. The top of the synrift complex (or top of SDRs like units) is a bright boundary with age ~100 Ma.  Sometimes the top of the synrift complex contains conical edifices with a chaotic internal structure. Their height is 400-800 m. This is possible underwater volcanoes. The base of the synrift complex (or base of SDRs like units) is unclear and corresponds to the top of the acoustic basement. This age is near 125 Ma. We assume that SDRs like units and volcanos were formed during the HALIP epoch (~125-80 Ma).

 We found a regularity in the distribution of half-graben and SDRs like units. They are all located at the edges of the basins near the slopes of the uplifts. Two axes can be distinguished as the centers where SDRs like units and half-grabens converge. The western axis goes through Podvodnikov Basin and corresponds with the central uplift of the Podvodnikov basin. Reflectors dip from the western slope of the Mendeleev Rise from one side and from the Lomonosov Ridge from another. They converge near the central uplift. The eastern axis goes through Toll, Mendeleev, Nautilus and Stefansson Basins. In Toll and Mendeleev Basins reflectors and half-grabens dip from east slope of Mendeleev Rise from one side and from Chukchi Plateau from another. The Stefansson Basin looks similar to the Podvodnikov Basin. The central uplift is located in the center of the Stefansson Basin. Reflectors and half-grabens dip from Alpha Rise from one side and from Sever Spur from another. We have compiled a map of the distribution of SDR’s like units, volcanoes and half-grabens based on the map of the acoustic basement.

This study was supported by the Russian Science Foundation (Grant 22-27-00160).
Advanced modelling of the multiphase chemistry of methylamines with CAPRAM
Authors: Hoffmann Erik Hans , Tilgner Andreas , Herrmann Hartmut
Published: March 2022

Amines are important but poorly studied organic constituents in the marine atmosphere. There is strong evidence that within the marine boundary layer, the formation of new aerosol particles and the increase in particle mass is influenced by amines. However, very high uncertainties still exist with respect to: the sources, the further chemical reactions within the multiphase chemical system of the marine atmosphere, and the contribution to the marine aerosol mass. A deeper understanding of the amine-initialized formation of organic nitrogen in marine aerosol particles requires fundamental mechanistic modeling studies of the multiphase oxidation of amines.
Therefore, a detailed multiphase chemistry mechanism, the CAPRAM Amine module, has been developed to describe the oxidation of ammonia (NH3), monomethylamine (MMA), dimethylamine (DMA) and trimethylamine (TMA) in the atmosphere. This mechanism is the first that considers the formation of the auto-oxidation products from DMA and TMA and their further oxidative fate in both the gas and aqueous-phase. Overall, the mechanism currently contains 541 reactions, thereof 232 gas-phase reactions 52 phase transfer reactions, and 257 aqueous-phase reactions.
In the present study, first simulations of an idealized marine environment were performed investigating the chemical processing of amines under cloud and non-cloud conditions. The simulations indicate that uptake is a main loss term for DMA whereas for TMA it is oxidation in the gas phase. This shows that models considering amine driven new particle formation have to consider both uptake and gas-phase oxidation. Interestingly, the chemical rates analyses revealed an unexpected important chemical conversion of amines during cloud conditions, where TMA, DMA and MMA are degraded into DMA, MMA and NH3, respectively. This unexpected fate of amines can have implications for the current unknown high DMA concentrations in the marine boundary layer that cannot be explained by oceanic emission alone. Because of the importance of DMA and TMA for new particle formation, the uncovered processes have to be thus analyzed by laboratory studies in more detail.
Inter-annual river patterns change detection using machine learning
Authors: Li Qing , Barrett Brian , Boothroyd Richard , Hoey Trevor , Williams Richard
Published: March 2022

River patterns in the tropics usually exhibit seasonal changes because of strongly seasonal rainfall and its impact on geomorphological processes. However, studies on tropical rivers are much less than those on temperate rivers, and so these seasonal patterns have not been quantified. To fill some of this research gap, this paper employs machine learning methods using Sentinel-2 multispectral remote sensing images to classify geomorphological units in Bislak River, Laoag River and Abra River in west Luzon, the Philippines. In this study, we firstly designed a workflow for river pattern classification, which was validated for the three rivers at different spatial and temporal scales. Then, 5.5 years of river patterns, defined using three morphological units, in the three rivers were generated for further geomorphological analysis. The classification results were analysed in terms of both spatial and temporal aspects. The results show a variety of relationships between channel width and each landform unit (wetted channel; exposed sediment bar; vegetated bar). The analysis shows that channel width has an impact on the area occupied by vegetation (the bigger the river, the stronger the correlation between channel width and vegetation). We present a way to analyse interactions between geomorphic units at seasonal scales using time series of correlations. The rivers were divided into sub-reaches based on observed patterns of water frequency and confinement, and then temporal analysis was undertaken for each sub-reach. This analysis used Ensemble Empirical Mode Decomposition (EEMD) which decomposed the time series and precipitation. The EEMD results indicate that areas occupied by water and vegetation commonly show synchronised fluctuations with precipitation, while sediment bars have an anti-phase oscillation with precipitation. The results suggests that deviations from periodic consistency in patterns may reflect the influence of extreme events and/or human disturbance. Correlation results show that the total area of unvegetated bars is usually the most stable landform unit in all three rivers, and that the vegetated area changes less in narrower channels. Confinement, due to hillslope and terrace topography, and the impact of fault are also considered. The methods for generating time series of landform unit data and time series analysis used here provide a framework for analysis of tropical rivers that are subject to regular, frequent and dynamic changes of planform.
Hydroeconomic Analysis for Climate Adaptation Guidance under Future Climate Water Stress
Authors: Baccour Safa , Ward Frank , Albiac Jose
Published: March 2022

Climate water stress internationally challenges the goal of achieving food, energy, and water security.  This challenge is elevated by population and income growth and by considerable uncertainty about future water supplies. Increased climate water stress levels reduce water supplies in many river basins and intensify competition for water among sectors and over time periods.  Organized information is needed to guide river basin managers and stakeholders who must plan for a changing climate through innovative water allocation policies, trade-off analysis, vulnerability assessment, capacity adaptation, and infrastructure planning. Several hydroeconomic models have been developed and applied assessing water use in different sectors, counties, cultures, and time periods.  However, none to date has presented an optimization framework by which historical water use and economic benefit patterns can be replicated while showing measures to adapt to future climate water stresses to inform the design of policies not yet implemented. This paper’s unique contribution is to address this gap by designing and presenting results of a hydroeconomic model for which optimized base conditions match observed data water use and economic welfare for several urban and agricultural uses at several locations in a large European river basin for which water use supports a population of more than 3.2 million.  We develop a state-of-the arts empirical dynamic hydroeconomic optimization model that integrates hydrology, economics, climate stress, and institutional water sharing measures. The model is used to discover land and water use patterns that optimize sustained farm and city income under various levels of climate-water stress. Findings using innovative model calibration methods allow for the discovery of efficient water allocation plans as well as providing insight into marginal behavioral responses to climate water stress and water policies. Results show that a water trading policy for handling climate water stress provides more economically efficient water use patterns, reallocating water from lower valued uses to higher valued uses such as urban water.  The Ebro River Basin in Spain is used as an example to investigate water use adaptation patterns under various levels of climate water stress. That basin’s issues and challenges light a path to relevance for other river basins internationally.
Seasonal signal and regional sea level variability over the past 25 years 
Authors: Jevrejeva Svetlana , Palanisamy Hindumathi
Published: March 2022

In this study we have quantified the role of seasonal cycles in globally observed sea level variability from satellite altimetry over 1993-2018. We show the largest seasonal variability, with contribution more than 80% of total variance, is detected in particular regions- the marginal seas over the continental shelf regions in South East Asia and Gulf of Carpentaria, tropical Atlantic along the coastal regions of east Atlantic Ocean, Arabian Sea, regions of Mediterranean, Red Sea with amplitudes greater than 20cm in majority of these locations. The rest of the ocean, mainly deep open ocean, exhibits strong signatures of non-seasonal variability related to interannual and longer scale cycles.

For the regions with large seasonal variability (e.g. South East Asia coastline), analysis of seasonal variability demonstrate a good agreement in amplitude and phase from satellite altimetry and tide gauges records. While steric contribution can explain more than 80% of total variability in the deep ocean areas, in shallow areas we explain a large part of variability though wind driven during the two monsoon seasons, and not attributed to the steric changes.