bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the realism of distributed hydrological models in mountainous catchments using remotely sensed observations
Authors: Vásquez Nicolás , Mendoza Pablo A. , Cortés Nicolas
Published: March 2022

Over the past decades, remote sensing products have contributed with additional information on various components of the water cycle, especially in sparsely monitored areas. Although the inclusion of spatial patterns derived from satellite products can improve the performance of distributed hydrological models, simulating streamflow at interior points remains a challenge. In this study, we characterize the added value of incorporating remotely sensed soil moisture, fractional snow covered area, evapotranspiration and land surface temperature in the calibration of a distributed hydrological model. To this end, we configure the variable infiltration capacity (VIC) model at a 5-km horizontal resolution in two catchments located in Central and Southern Chile, and conduct calibration experiments with only streamflow data, and combining streamflow with remotely sensed spatial patterns. Specifically, we examine: (i) the effects at interior “ungauged” points, (ii) the benefits of adding gauging points in the calibration process, and (iii) the benefits of including additional variables. Previous results show that including spatial patterns in the calibrations allows a better representation of interior ungauged points, similar to including more streamflow gauges at interior locations.
The usefulness of applying morphometric analyses in intrabasinal faults: the Galera Fault (central Betic Cordillera, S Spain)
Authors: Medina-Cascales Ivan , García-Tortosa Francisco Juan , Martín-Rojas Iván , Pérez-Peña José Vicente , Alfaro Pedro
Published: March 2022

Here we prove the usefulness of applying morphometric analyses, typically used in basin-border faults, to evaluate the geomorphic expression of an intrabasinal structure. The target fault of our study is the Galera Fault, a SW-NE, ca. 30 km-long fault located in the Guadix-Baza Basin (central Betic Cordillera, southern Spain). This fault is characterized by low displacement rates, with a major left-lateral (0.5±0.3 mm/yr) and minor (0.02-0.05 mm/yr) vertical slip components. Moreover, the Galera Fault cuts across the Plio-Quaternary basin infilling, so poorly-lithified sedimentary rocks crop out in both fault blocks.

Since the Guadix-Baza Basin was captured in the Middle Pleistocene, it has been dominated by extensive erosion, which has shaped a very young landscape influenced by the activity of the Galera Fault. To evaluate the imprint of the fault on the landscape, we carried out an analysis of the topography and the drainage network from high-resolution digital elevation models (DEMs). In addition, we apply different geomorphic indices, such as the profile relief ratio (PRR), the normalized channel steepness index (ksn), the asymmetry factor (AF), and the valley floor width-to height ratio (Vf).

Our study evidence that the combination of low slip rates and the high erodibility of the juxtaposed rocks favors a rapid landscape response to fault displacement that erases many landscape effects related to active tectonics. This masking is more effective on features generated by strike-slip displacement, leaving only subtle evidence, such as local stream deflections and upstream widening of catchments. In contrast, geomorphic effects related to vertical displacement are better preserved, including the control of the geometry of the main rivers and morphological differences in the drainage network between the two fault blocks. On the upthrown block, streams are generally shorter, steeper and valley incision is more accentuated. These differences between fault blocks are reflected in the development of an impressive badland landscape that is restricted to the upthrown block.

Slow intrabasinal faults can be difficult to detect in studies involving structural mapping, seismic hazard assessment, or exploration of resources, especially when they offset highly erodible deposits and do not present a marked uplift. However, here we demonstrate that the geomorphic anomalies that these structures can leave on the landscape can be identified by applying a proper morphometric analysis.
Lessons from the 2018-2019 European droughts: A collective need for unifying drought risk management
Authors: Blauhut Veit , Stölzle Michael , Ahopelto Lauri , Brunner Manuela , Teutschbein Claudia , Wendt Doris ,   Drought Risk Europe - a Panta Rhei working group
Published: March 2022

In recent years, drought impacts have been perceived as more severe and frequent than those of past events throughout Europe. Due to the heterogeneity of Europe’s hydro- climatological situation as well as the multiple Nations on the continent, drought events and their impacts vary with respect to location, sector, extent, duration and scale. In order to understand recent effects of drought and their possible drivers, national representatives distributed a uniform questionnaire to water management related stakeholders at different scales of 28 contributing countries. The survey focused on collecting information on stakeholders’ perceptions of drought, impacts on water resources and beyond, water availability and current drought management strategies at national and regional scales. The survey results were compared with the actual drought hazard information registered by the European Drought Observatory (EDO) for 2018 and 2019. The final results of the study highlight the diversity among national drought event perception and the value of implemented drought management strategies. Only few countries practise drought management, an absence of drought management is mostly attributed to lacking of resources, but also lacking political will for implementation and lacking political advice. Supported by the national representatives’ perspectives, the study concludes with an urgent need to further reduce drought impacts by constructing and implementing a European macro-level drought governance approach, such as a directive, which would strengthen national drought management and lessen harm to human and natural potentials.
Quantification of SO2 emission rates from the Kilauea volcano in Hawaii by the divergence of the SO2 flux using S5P-TROPOMI satellite measurements and comparison to results from ground-based observations
Authors: Jost Adrian , Beirle Steffen , Dörner Steffen , Borger Christian , Warnach Simon , Bobrowski Nicole , Kern Christoph , Wagner Thomas
Published: March 2022

With a nearly continuously effusive eruption since 1983, the Kilauea volcano (Hawaii, USA) is one of the most active volcanoes in the world. From the beginning of May till the end of August 2018, a sequence of eruptions on the Lower East Rift Zone (LERZ) caused an enhanced outbreak of volcanic gases and aerosols, releasing them into the troposphere. Since these gases and particles affect climate, environment, traffic, and health on regional to global scales, a continuous monitoring of the emission rates is essential.

As satellites provide the opportunity to observe and quantify the emissions remotely from space, their contribution to the monitoring of volcanoes is significant. The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite was successfully launched by the end of 2017 and provides measurements with unprecedented level of detail at a resolution of 3.5 x 7.0 km2 (3.5 x 5.5 km2 since August 2019). This also allows for an accurate retrieval of trace gas species such as volcanic SO2.  

Here, we show that the location and strength of SO2 emissions from Kilauea can be determined by the divergence of the temporal mean SO2 flux. This approach, which is based on the continuity equation, has been successfully demonstrated for NOX emissions of individual power plants (Beirle et al., Sci. Adv., 2019).

The present state of our work also indicates that emission maps of SO2 can be derived by the combination of satellite measurements and wind fields on high spatial resolution. As the divergence is highly sensitive on point sources like the erupting fissures in the 2018 Kilauea eruption, they can be localized very precisely. The obtained emission rates of about 1.5 Mt are substantially lower than the ones reported from ground-based measurements in other studies like the one from Kern et al. (Bull. Volcanol., 2020). 

We discuss several potential reasons for the discrepancies between the ground- and satellite-based observations like e.g. uncertainties of the air mass factor or possible rapid destruction of SO2 in the presence of clouds.
Animal bone chars as sorbents and providers of ammonium nitrogen from biogas digestates
Authors: Soja Gerhard , Sörensen Anders , Drosg Bernhard , Gabauer Wolfgang , Schumergruber Alexander , Dunst Gerald , Meitner Daniela , Guillen Elena , Ortner Markus , Pfeifer Christoph
Published: March 2022

Biochars are well-known for their high sorption capacity of cationic substances. Whereas the pyrolysis of vegetation-based feedstock produces biochar with high carbon concentrations (70-90 %), these chars contain only very small fractions of plant-relevant macronutrients with good bioavailability. The usage of animal bones as pyrolysis feedstock, however, produces phosphorus-rich biochars (10-15 % P) that are low in carbon (10-20 % C). The deficiency in nitrogen of these bone chars can be compensated for by sorbing nitrogen prior to use them as soil improvers.

Among the different possibilities to enrich nitrogen-poor biochars with ammonium, the use of biogas digestate is one of the most promising options in terms of nitrogen recycling and reduction of gaseous nitrogen losses. Direct applications of biogas digestate may result in high ammonia losses during spreading of the liquid and in the first days after soil incorporation. The use of membrane distillation for separating digestates into an ammonium-enriched and an ammonium-poor fraction allows the use of a sorbate with up to 10 g NH4+ L-1 that can be used to enrich bone chars with easily bioavailable nitrogen.

Based on measurements of cation exchange capacity (CEC), it appears that ion exchange plays an important role in the sorption of ammonium. Bovine bone char showed higher CEC than pig bone char. Apparently, the nitrogen enrichment of bone char from ammonium sulfate solutions had increased the availability of the preexisting bone char nitrogen by acting as a mild acid. By testing the nitrogen availability of N-enriched bone chars with a standardized plant test (“Neubauer-Test”), we observed that chars enriched with the biogas digestate ammonium-rich fraction were able to significantly improve the performance of bone char-treated plants (+135 % in plant dry matter, +130 % in plant N uptake compared to non-enriched bone char). This result was achieved by using bovine ribs as pyrolysis feedstock and biogas digestate from the same abattoir that had produced the cattle bones as residues from carcass processing for food production. This case study could show that the combined use of liquid and solid abattoir wastes is able to produce an efficient organic NP-fertilizer and replacement for mineral fertilizer.

Acknowledgments: The authors are grateful to the Austrian Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology via the Austrian Research Promotion Agency (FFG: “Produktion der Zukunft”, 24th call, project nr. 864849) for financial support of the project NutriCoal.

 
Sub-seasonal evolution of ice cliffs captured with time-lapse photogrammetry
Authors: Kneib Marin , Miles Evan S. , Buri Pascal , Fugger Stefan , McCarthy Michael , Zhao Chuanxi , Shaw Thomas E. , Truffer Martin , Westoby Matthew , Yang Wei , Pellicciotti Francesca
Published: March 2022

Ice cliffs are important contributors to the mass balance of debris-covered glaciers, especially in High Mountain Asia where they can account for one sixth of the melt of  debris-covered glacier tongues, despite covering less than 10% of their area. These features have been shown to evolve, appear and disappear rapidly from year to year, with high variability in relative area and number. It has been hypothesized that ice cliffs expand and melt more rapidly during the monsoon (June-September), but there are very few observations during this period. Here, we use arrays of time-lapse cameras to reconstruct the geometry of four ice cliffs at a weekly timestep over a period of four to six months at two monsoon-affected sites: Langtang Glacier in Nepal, and 24K Glacier in South-Eastern Tibet. We use Structure-from-Motion photogrammetry to derive point clouds and Digital Elevation Models (DEMs) of the glacier surface, using the stable background terrain to constrain viewing geometries and DEM errors. This technique (time-lapse photogrammetry) enables a high accuracy, quantitative measurement of processes occurring at the cliff-scale (elevation uncertainties stay below 30cm at a distance of 300m from the cameras) and at high temporal resolution over the monsoon season, when dense cloud cover and intense precipitation prevent field- or satellite-based observations. We derive the melt patterns of these cliffs from the differencing of the weekly DEMs by accounting for glacier flow. We compare the observed melt patterns with the modeled energy-balance at the cliff surface and use these observations to quantify the influence of debris slumping and redistribution, as well as supraglacial ponds and streams on the melt patterns of these cliffs. The results highlight the seasonal variations of cliff melt, which occurs at up to 8 cm/day during the monsoon, twice as high as observed in the pre- and post-monsoon period. Our energy-balance results indicate that melt rates are driven by incoming long- and shortwave radiation, and are thus highly dependent on the cliff slope and aspect, as substantiated by our photogrammetric measurements. The observations also demonstrate the competitive influence of debris, which progressively reburies the cliff by accumulating at its surface, and supraglacial streams and ponds, which maintain the cliff slope by preventing debris accumulation at the base. These results will help in understanding the surface evolution of debris-covered glaciers and enable a better representation of ice cliff melt and evolution in glacio-hydrological models.
Assessment of GHGSat’s constellation one year after its first phase deployment
Authors: Strupler Mathias , Jervis Dylan , MacLean Jean-Phillipe , Marshall David , McKeever Jason , Ramier Antoine , Tarrant Ewan , Young David
Published: March 2022

Methane emissions from industrial activities represent a significant fraction of total greenhouse gas emissions. It is vital to provide industrial site operators with accurate and timely information about their emissions -- GHGSat’s constellation was built for this purpose. Each of the constellation satellites can do multiple measurements of 150 km2 domains each day with a pixel resolution of 25 meters allowing to detect, quantify and attribute emissions to a given facility. With 3 satellites currently in operation, this allows multiple measurements of a site in a year and help operators minimize their emissions.

We will present the performance of our instruments showing a column precision of 1% of background and a detection threshold of 100 kg/h for point sources. Examples from a variety of anthropogenic sources will illustrate the system capability.  A statistical analysis of all detected emissions will serve to evaluate the distribution of global source rates, source intermittency and breakdowns by region and by sector. An estimate of emissions mitigated thanks to GHGSat’s constellation will also be presented. Finally, the schedule of the next phases of the constellation will be outlined.
Distributed feedback quantum cascade laser absorption spectroscopy for airborne methane measurements
Authors: Butkus Laurynas , Ežerinskis Žilvinas , Plotnikov Artur , Koroliov Anton , Šapolaitė Justina , Pabedinskas Algirdas , Plukis Artūras , Remeikis Vidmantas
Published: March 2022

The intensive development of industry, agriculture, and transportation causes many issues related to the negative impact on the environment and human health. Harmful products of human technogenic activity accumulate in the environment. Due to increasing concentrations of greenhouse gases (methane, carbon dioxide, etc.), the effects of global warming are already being observed. Research that addresses the challenges of climate change mitigation and creates science-based assumptions for new environmental monitoring systems and technologies is becoming more and more relevant.

A new two drone system with a variable optical path for measuring greenhouse gases (CH4, CO2) is currently in development. Here, we will present a distributed feedback (DFB) quantum cascade laser absorption spectroscopy system which is used for measuring methane concentrations in the atmosphere. The DFB laser for methane measurements is being operated at 3371.5 nm and 3368.8 nm, for higher and lower concentrations respectively.

The results of the Allan-Werle deviation analysis will be introduced. Also, measurement capabilities and detection limits of the system will be presented and discussed.
Heat and salt budgets in the Hornsund fjord
Authors: Przyborska Anna , Strzelewicz Agnieszka , Muzyka Maciej , Jakacki Jaromir
Published: March 2022

Climate change is affecting all the Svalbard fjords, which are more or less subject to global warming.  In situ observations in the Hornsund fjord indicate that more and more warm Atlantic water is reaching the fjord as well, and this may influence the rate of melting of sea ice and glaciers, which is likely to increase.  

More freshwater enters the fjord in several different ways. Melting glaciers bring freshwater in the form of surface inflows from freshwater sources, in the form of submarine meltwater at the interface between ocean and ice, and in the form of calving icebergs.  Retreating glaciers and melting sea ice allow the warm Atlantic waters to reach increasingly inland fjord basins and more heat stored in the fjords causes increased melting of the inner fjord glaciers.  The increasing amounts of freshwater in the fjord can change the local ecosystem.

Estimates of the heat and the salt fluxes will give a better understanding of how the ocean interacts with the glaciers through submarine melting and vice versa, how glaciers interact with the ocean through freshwater supply.  Budgetary conditions will be calculated from the high resolution model results (HRM) of velocity, temperature and salinity for the interior of the Hornsund fjord.

Calculations were carried out at the Academic Computer Centre in Gdańsk
Comparison of soil organic matter composition under differentland uses by DRIFT spectroscopy
Authors: Thai Saven , Pavlů Lenka , Tejnecký Václav
Published: March 2022

Soil organic matter (SOM) plays vital importance for biological, chemical, and physical soil improvement and productivity. Organic matter composition also depends on different types of vegetation covers. Thus the study was aimed to estimate and characterize the soil organic matter (SOM) under different land uses (cropland, grassland, and forestland) and depths (0-10 cm, 10-20 cm, and 20-30 cm) in Prague Suchdol. Ninety samples of disturbed soil were collected within different land uses and within different depths. The soil organic matter (SOM) composition was assessed by diffuse reflectance infrared fourier transform spectroscopy (DRIFT). Humic and fulvic acid were extracted from soils and their composition was also assessed by DRIFT. Additionally, dissolved organic carbon (DOC), humus quality as ratio between absorbances of soil extract with sodium pyrophosphate at the wavelengths 400 and 600 nm, soil organic carbon (by the rapid dichromate oxidation technique), were determined on the samples as well as physical characteristics as bulk density. The data were analysed statistically by statistical package for the social sciences (SPSS) version 20. The results indicated that pHKCl is significantly different among land uses. Cropland had the highest values of pHKCl with a range from 7.76 to 6.86, followed by grassland with a range from 5.72 to 5.93 and forestland with 3.34 to 3.65, respectively. However, the humus quality was significantly different for all depths where forestland had the lowest humus quality compared to grassland and cropland, respectively. The soil organic carbon deviates statistically in depth 0-10 cm and 20-30 cm, while the depth in between from 10 to 20 cm showed no substantial difference among the land uses. Nonetheless, the result revealed that the largest differences of the spectra in the composition of organic matter were observed in the upper parts of the soil profile. The forest soil spectra had more intense aliphatic bands, carboxylic, and CH bands than spectra of grassland and cropland soils. The difference of HAs spectra was at 3 010 to 2 800 cm-1 where the most intensive aliphatic bands were in forest soil HAs, followed by grassland and cropland soil HAs. The grassland topsoil FAs spectrum differs most from the other land uses. It has lower peaks around 1 660–1 600 cm-1 and 1 200 cm-1 than cropland and forest. The concentration of low molecular mass organic acid (LMMOA) was the highest in the forest soil and the most abundant acid was citrate.
Fertigation management of mixed-species plantation versus monoculture in plantation forestry: key aspects and future perspective.
Authors: Rabbai Andrea , Krause Stefan , Kettridge Nicholas , Ullah Sami , Curioni Giulio , Rob Mackenzie Rob , Hart Kris
Published: March 2022

According to the Forest European Process, the recent Climate Change Conference (COP26), and EU policies, conservation of forest ecosystems is a critical step in mitigating climate change and combating deforestation; accordingly plantation forests will be critical in achieving these goals. While limitations in monoculture plantation are well established in silvicultural practices and documented in research studies, in the face of intensifying climate change and resources scarcity, the need for knowledge on mixed-species plantations has grown. There has been also a recent develop in innovative and sustainable forest management practices, including irrigation and fertilization (fertigation) that aim to improve the productivity of forestry plantations, and therefore their carbon sequestration capacity, as well as the ecosystem services associated with healthy forests. However, the exact effects of fertigation on forests plantation have yet to be established. This study examines the growth patterns, productivity, and carbon storage capacity of four–year-old mixed-species and monoculture plantations in response to an intensive fertigation management. Particularly, our findings highlight differences in tree growth patterns and their performance in paired experimental plots based on different soil types. Such differences are associated varying soil moisture conditions due the interaction of fertigation and the soil water holding capacity. In general, trees growth is higher in sandy soil, due to the positive relation between high soil water diffusivity and fertigation. On the other hand, no such tree growth has been observed in clay soil, most likely due to the high susceptibility to waterlogging, which requires careful fertigation management to avoid limiting conditions for the healthy development of young forest plantation. Our research provides important insights into how young plantation trees respond to different soil moisture conditions, which can aid to in the design and fertigation management of mixed-species plantations resulting in more productive, biodiverse, economically viable, and healthier forests than monocultures.

 

 
From Astronomy to Chemistry: Towards a Continuous Path for the Origins of Life
Authors: Todd Zoe
Published: March 2022

The origins of life on Earth have been a longstanding scientific puzzle, prompting scientists from Orgel to Sagan to grapple with the fundamental question of “how did we get here?” While a complete theory of the origin of life on Earth - with experimental support and no unresolved issues - has yet to be elucidated, certain pieces of the puzzle have seen recent progress. We need to have a cohesive model of the origins of life on Earth to better inform which exoplanets should be observational targets for upcoming telescopes and what tools will be necessary in future missions to deduce the presence or absence of life on a potentially habitable world. Fortunately, we have unprecedented access to the one planet where we know circumstances led one way or another to life’s origins: the Earth. While astronomers find exoplanets and planetary scientists explore the possibility for habitability in our Solar System, chemistry can play an invaluable role in facilitating the search for life beyond Earth. If we better understand the chemical reactions and pathways possibly leading to the origins of life on Earth, we can better inform and constrain the search for life in other planetary environments. By working towards a continuous and plausible pathway towards delineating the origins of life on Earth, we can place constraints on the astronomical, planetary, and chemical environments necessary for habitability. 
Spatially calibrating polycyclic aromatic hydrocarbons (PAHs) as proxies of area burned by vegetation fires
Authors: Vachula Richard S. , Karp Allison , Denis Elizabeth , Balascio Nicholas , Canuel Elizabeth , Huang Yongsong
Published: March 2022

Many regions worldwide have experienced increasing wildfire activity in recent years and climate changes are predicted to result in more frequent and severe fires. Reconstruction of past fire activity offers paleoenvironmental context for modern and future burning. Pyrogenic polycyclic aromatic hydrocarbons (PAHs) have been increasingly used as a molecular biomarker for fire occurrence in the paleorecord and offer opportunity for nuanced reconstructions of fire characteristics. A suite of PAHs is produced during combustion, and the emission amount and assemblage is influenced by many variables including fuel type, fire temperature, and oxygen availability. Despite recent advances in understanding the controls and taphonomy of these biomass burning markers, the spatial scale of this proxy is unknown. Measurements of PAH fluxes preserved in a lake sediment archive from the Sierra Nevada, California were compared with a historical geographic information system dataset of area burned up to 150 km distance from the lake to determine the spatial scales for which these biomarkers are reliable proxies of burning. The PAH fluxes in the Swamp Lake sediments record a change in the relative anthropogenic and pyrogenic sourcing of PAHs. Anthropogenic pollution sources could explain why some PAHs (fluoranthene (Fl), pyrene (Py), benz[a]anthracene (BaA), retene (Ret), benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DA) and ideno[1,2,3-cd]pyrene (IP)) did not correlate with area burned within 150 km. This indicates that individual PAHs may have different efficacies in recording area burned and be more susceptible to masking of fire signals by pollution sources. Despite these complications, we find that the PAHs naphthalene (Na), acenaphthene (Ace), fluorene (F), and anthracene (An) are reliable local proxies of area burned (within 40 km), whereas the PAHs phenanthrene (Phe), chrysene (Ch), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), and benzo[g,h,i]perylene (Bghi) are both reliable local (within 36 km) as well as more regional (as much as 75 km for phenanthrene (Phe), chrysene (Ch), and benzo[g,h,i]perylene (Bghi) or 150 km for benzo[b]fluoranthene (BbF) and benzo[k]fluoranthene (BkF)) area burned proxies. Comparisons of PAH fluxes with charcoal accumulation rates in the same sediments suggest that pyrogenic particulate transport modulates low to mid-molecular weight PAHs via adsorption. Overall, the results indicate that PAH records integrate a combination of spatial signals of area burned and measurement of individual PAHs may enable cross-scale paleofire reconstructions.
Disentangling the mechanisms of ENSO response to volcanic eruptions
Authors: Pausata Francesco S.R. ,   et al.
Published: March 2022

Large explosive volcanic eruptions can have major impacts on global climate, affecting both radiative balance and inducing interannual-to-decadal dynamical alterations of the atmospheric and oceanic circulation. Despite some discrepancies across studies regarding the response of ENSO to volcanism based on paleoclimate data, the majority of ENSO reconstructions display an El Niño–like warming in the year of eruption, while none display a significant La Niña–like response. Furthermore, there has been an emerging consensus from the numerous coupled General Circulation Model studies investigating the impact of tropical volcanism on ENSO, with the overwhelming majority displaying an El Niño–like warming occurring in the year following the eruption. However, the mechanisms that trigger ENSO anomalies following volcanic eruptions are still debated. The center of the argument is understanding how volcanism affects the trade winds along the equatorial Pacific.

We performed a series of sensitivity experiments using the Norwegian Earth System Model (NorESM1-M) designed to shed light on the processes that govern the ENSO response to volcanic eruptions as a function of the regional distribution of the aerosol forcing. Specifically, a uniform stratospheric volcanic aerosol loading was imposed over different parts of the tropics and extra-tropics to test the four main mechanisms invoked to explain the ENSO response to volcanic eruptions: 1) the ocean dynamical thermostat (ODT) mechanism; 2) the cooling of the Maritime Continent (MC) mechanism; 3) the cooling of tropical northern Africa (NAFR) mechanism; and 4) the Intertropical Convergence Zone shift mechanism. In this contribution, we will present results for NorESM1-M, illustrate their implications for understanding of forced ENSO dynamics and discuss how our approach can give benefit to multi-model assessments of ENSO response to volcanic forcing.
Process-Based Estimates of Seasonal Catchment Hydrology: Dimensionless Models
Authors: Wang Zeqiang , Woods Ross
Published: March 2022

Catchment functions (consisting of partition, storage and discharge) are difficult to measure or model, especially considering the wide variety of landscape forms (e.g. plant canopy and soil properties) and variable climate forcing (e.g. precipitation and radiation). After formulating an analytical model to predict the seasonal water balance of the canopy, the root zone, and the saturated zone by using functions of six dimensionless parameters (Woods, 2003, Advances in Water Resources), Woods (2009, Advances in Water Resources) developed a related model for seasonal snowpack dynamics. This presentation will use enhancements of these two simple models to estimate evaporation (E) and changes in water storage (dS/dt) and then the catchment runoff (Q), driven by summary statistics of precipitation (P), temperature and potential evaporation, based on the seasonal water balance (dS/dt= P-E-Q). In this study, we (i) firstly quantify the parameters (e.g. interception capacity relative to rainfall and melt factor) used in this improved model, using an a priori approach; (ii) assess this model in many catchments around the world by using existing global data products; (iv) identify the dominant parameters controlling the water balance; (v) discuss the limitations of this model. As a result, we will find in which situations it is possible to simply and reliably estimate seasonal variation in river flow without flow measurements, and other situations where model refinement is needed. This is important both for improving our understanding of catchment hydrology, and for predicting the seasonal hydrological differences between various hydro-climatic conditions or catchments, especially in locations with sparse measurements.
Influence of anthropogenic forcing and internal climate variability on winds over the Amundsen Sea shelf
Authors: Holland Paul , Bracegirdle Thomas , Dutrieux Pierre , Naughten Kaitlin , Schneider David , O'Connor Gemma , Steig Eric , Jenkins Adrian
Published: March 2022

Ocean-driven ice loss from the West Antarctic Ice Sheet (WAIS) is a significant contributor to sea-level rise. In the 20th century, modelled wind trends over the Amundsen Sea imply an ocean warming that could explain this ice loss. In this presentation, climate model simulations are used to separate internal and anthropogenic influences on these wind trends. Tropical Pacific variability is found to be most influential in winter and over the Amundsen Sea continental shelf, while greenhouse gases and ozone depletion are dominant in summer and north of the shelf. Model projections feature strong wind trends that imply future ocean warming. In these projections, moderate greenhouse-gas mitigation has no influence on wind trends near the Amundsen Sea shelf. Internal climate variability creates a large and irreducible uncertainty in winds over the shelf. This complex regional and seasonal interplay between anthropogenic forcing and internal variability may determine the attribution and projection of ice loss from the WAIS.
The influence of proglacial lakes on climate and surface mass balance of retreating ice sheets – An Investigation of the Laurentide and Fennoscandian ice sheets,13 ka BP
Authors: Sijbrandij Lianne , Gierz Paul , Hinck Sebastian , Krebs-Kanzow Uta , Lohmann Gerrit , Niu Lu
Published: March 2022

This study investigates how large proglacial lakes affected regional climate and surface mass balance (SMB) of retreating ice sheets during the last deglaciation. For this purpose we have modified the atmosphere model ECHAM6. The approach is here to limit the surface temperature of proglacial lakes to values below 4°C, while other lakes in ECHAM6 can freely evolve according to a mixed layer scheme.

As a first application we investigate the impact of proglacial lakes during the Allerød interstadial at 13 ka (ka is thousand years before present) with three atmosphere stand-alone experiments:

(i) with 13ka land surface boundary conditions (GLAC1d, Ivanovic et al., 2016) and a modern lake configuration

(ii) same as (i) but with additional lakes around the North American and Fennoscandian Ice Sheets

(iii) same as (ii) but the additional lakes are treated according to our proglacial lake approach.

Over the ocean we use boundary conditions taken from a 15ka coupled climate simulation. These three simulations were evaluated with respect to the regional climate response and the SMB was calculated using the diurnal Energy Balance Model (dEBM, Krebs-Kanzow et al., 2021). Preliminary results are indicating an overall positive effect of regular lakes, and in particular proglacial lakes, on the SMB of the great ice sheets over Northern America and Scandinavia during the Allerød interstadial.

 

References:

Ivanovic, R. F., Gregoire, L. J., Kageyama, M., Roche, D. M., Valdes, P. J., Burke, A., Drummond, R., Peltier, W. R., and Tarasov, L.: Transient climate simulations of the deglaciation 21–9 thousand years before present (version 1) – PMIP4 Core experiment design and boundary conditions, Geosci. Model Dev., 9, 2563–2587, https://doi.org/10.5194/gmd-9-2563-2016, 2016.

Krebs-Kanzow, U., Gierz, P., Rodehacke, C. B., Xu, S., Yang, H., and Lohmann, G., 2021: The diurnal Energy Balance Model (dEBM): a convenient surface mass balance solution for ice sheets in Earth system modeling, The Cryosphere, 15, 2295–2313, https://doi.org/10.5194/tc-15-2295-2021.
Effects on soil water content and productivity of selected crops in a field experiment with rain-out shelter vs. control plot in the Czech Republic
Authors: Thaler Sabina , Eitzinger Josef , Hlavinka Petr , Pohankova Eva , Trnka Miroslav
Published: March 2022

Field experiments based on the manipulation of the crops' environment are crucial to determine the response of crops to the expected climatic conditions in near future. The number of droughts in Central Europe is expected to increase and it is crucial to investigate how this will affect agriculture. An experimental site in Domanínek, Czech Republic, is located at 49°31'42 "N, 16°14'13 "E, at an altitude of 560m. The climatic conditions are described as cool and dry, the average annual precipitation was 609.3 mm and the mean annual temperature was 7.2 °C between 1981 and 2010. This area is characterised by low soil quality and the potential risk of late frosts; the soil type is classified as dystric cambisol. The field experiment of rain guards to reduce soil water availability was carried out from 2015 to 2020. The main objective of this study was to evaluate the impact of different water availability (rain-out shelter vs. control) on the performance of selected field crops (spring barley, winter wheat, winter oilseed rape, rye, and silage maize). In addition to a weather station on the experimental field measuring air temperature, relative humidity, global radiation, precipitation and wind, soil moisture was also monitored in the different rain-out shelter and control plots with TDR sensors (0-30 cm). In this way, the reduction in the amount of precipitation during the rain-out shelter treatment could be confirmed by measuring the soil water content. To answer the research question, various descriptive statistical parameters such as mean, percentiles, minimum and maximum were used. For instance, the average yield reduction over the 6 years for maize was 16%, while for rape it reached a value of up to 32%. In addition, an analysis of variance (ANOVA) was applied to the yields of the different crops.

Acknowledgement: This study was conducted with support of SustES - Adaptation strategies for sustainable ecosystem services and food security under adverse environmental conditions (CZ.02.1.01/0.0/0.0/16_019/0000797).
The Arctic and NE Atlantic Realms: A comparison
Authors: Foulger Gillian , Nikishin Anatoly , Rodina Elizaveta , Startseva Ksenia , Gernigon Laurent , Geoffroy Laurent , Phethean Jordan , Chernykh Andrey
Published: March 2022

The disintegration of Pangea north of the Charlie Gibbs fracture zone led to the formation of the NE Atlantic and Arctic Oceans. Both these oceans are exceptionally complex in terms of diversity of the structures they contain and the sequence of events leading to their formation. Recent, extensive work by cross-disciplinary international groups has cast a great deal of new light on the structure and evolution of both oceans. Both have experienced fan-shaped oceanic-type spreading and ridge growth by linear propagation. Both contain shallow, linear bathymetric highs which comprise substantially or almost wholly, continental crust. There are also regions of continental crust, some hyper-extended, capped with lavas. Much of the NE Atlantic Ocean is floored by oceanic crust produced by classical, albeit piecemeal, oceanic spreading. The spreading rate is low and dwindles to ultra-low on the Gakkel Ridge in the Eurasia Basin of the Arctic Ocean. The Gakkel Ridge is flanked by linear, oceanic-like magnetic anomalies although it is not entirely clear whether these represent fully oceanic crust formation or whether some residual stretched continental crust remains beneath this region. The same may be true of the extinct Canada Basin spreading axis in the Amerasia Basin. Likewise, the nature and location of the continent-ocean transition in the NE Atlantic is currently under discussion and it has recently been proposed that the oldest linear magnetic anomalies, closest to the continental edges, characterize some form of magma-injected continental crust. A similar structure has been recently proposed for the Greenland-Iceland-Faroe Ridge  and the Alpha-Mendeleev Rise. What is currently unclear is the extents, in both oceans, of the three kinds of crust – true continental crust including microcontinents, magma-injected continental crust, and fully oceanic crust. There is furthermore likely a structural and geological continuum between these types. Classical linear magnetic anomalies are discontinuous between sections of the spreading ridge, raising the question of whether continuous fully oceanic crust connects these sections. In our presentation we will summarize what is known geologically and tectonically about both oceans, compare and contrast them, and outline their evolution. We will discuss the extents of the three types of crust and explore the implications for the history and mechanisms of ocean formation and the origins and extents of flood basalts. Of particular interest also is the control of pre-existing structure on the style of breakup.
Decoupling the impact of different carbonate system parameters from controlled growth experiments with deep-sea benthic foraminifera
Authors: Mojtahid Meryem , Depuydt Pauline , Mouret Aurélia , Rihani Fatine , Le Houedec Sandrine , Fiorini Sarah , Chollet Simon , Massol Florent , Dohou Francis , Filipsson Helena L. , Boer Wim , Reichart Gert-Jan , Quinchard Sophie , La Carole , Barras Christine
Published: March 2022

Insights into past marine carbon cycling and water mass properties can be obtained with reconstructions of the seawater carbonate system (C-system) through controlled experiments with accurate C-system manipulations. Benthic foraminifera (marine calcifying microorganisms) incorporate various elements into their biogenic calcium carbonate shells as a function of specific environmental parameters. We explore the use of Sr/Ca ratio of the calcite shells as a potential sea water C-system proxy after a controlled growth experiment with two deep-sea foraminiferal species (Bulimina marginata and Cassidulina carinata) and one intertidal species (Ammonia T6). To this aim, we decoupled carbonate chemistry in controlled growth experiments, i.e., changing pH at constant dissolved inorganic carbon (DIC) and changing DIC at constant pH. These experiments were performed for the first time with a new generation of environmental ecological experiment simulators (Ecolab system) allowing a precise control and monitoring of pCO2, temperature and humidity. Four climatic chambers were used with different concentrations of atmospheric pCO2 (180 ppm, 410 ppm, 1000 ppm, 1500 ppm). Preliminary results describe a positive correlation between Sr/Ca and the C-system (DIC/bicarbonate ion concentration) for Ammonia T6 and B. marginata, whereas no correlation with any of the C-system parameters was observed for C. carinata. We hypothesize that Sr/Ca ratios may serve as reliable proxy for the C-system for selected benthic foraminifera species.
Quantification of groundwater inflow along Moselle River by using a multiple tracer approach (222-Rn, Tritium, and δ18O)
Authors: Engel Michael , Mischel Simon , Quanz Sabrina , Frei Sven , Gilfedder Benjamin , Radny Dirk , Schmidt Axel
Published: March 2022

Groundwater represents a major component for runoff generation of large rivers systems. Its quantification is of uttermost importance during low flow periods and in the context of changing runoff dynamics due to climate change.

The present study focuses on the surface water-groundwater interaction using the example of the Moselle River, the second most important tributary of the Rhine. The river is classified as a federal waterway and has 12 barrages on German territory to ensure navigability all year round.

The research approach is based on the assumption that local groundwater inflow into the Moselle is detectable by increased 222-Rn concentrations in the river and that the δ18O composition of the river water approximates that of the groundwater. Therefore, we applied a numerical model for solving the 222-Rn and Tritium mass balance and a mixing model of δ18O and electrical conductivity.

For this purpose, water samples were taken at intermediate flow conditions (gauge Cochem: about 220 m³/s) in October 2020 along the Moselle on a stretch of 242 kilometers at high spatial resolution (every 2 km) to measure stable water isotopes and electrical conductivity. Integrated over the same spatial resolution, in-situ 222-Rn measurements were carried out. Tributaries and selected groundwater monitoring wells were sampled for the same analysis. Precipitation was collected at the station Trier of the German Meteorological Service on a monthly basis. In agreement with this measurement concept, another sampling campaign took place for selected reaches in August/September 2021 at lower discharges (Cochem gauge: about 94 m³/s).

In autumn 2020, diffuse groundwater inflow (approx. 0.17 to 0.3 m³/s) was detected for the shell limestone of the upper Moselle reaches and locally increased groundwater inflow for the middle reaches in the transition area to the Rhenish Slate Mountains and the Detzem barrage (approx. 1.4 to 2.4 m³/s). These estimates translate into groundwater contribution of the total Moselle discharge of 0.3 and 1.2 % respectively, which is much lower than those calculated by the mixing model (about 10 and 5 %, respectively). For August/September 2021, higher groundwater inflows in these areas are expected for both methods.

The evaluation to date indicates that 222-Rn is the most sensitive tracer to locations with increased groundwater inflow compared to tritium and stable water isotopes. While tritium results seem to strongly depend on the current flow conditions and the propagating river wave, stable isotope results are affected by the appropriate characterization of end-member hydrochemistry.
Transport and retention of motile cells in a complex microsystem comprising dead-end pores
Authors: Bordoloi Ankur , Scheidweiler David , de Anna Pietro
Published: March 2022

Disordered microstructures comprising dead-end pores are prevalent in soil, membranes and biological tissues. Predicting transport and dispersal patterns of microorganisms in such media is important for various natural and bio-engineered systems. Herein, we study the transport of motile and non-motile E. Coli bacteria cells through a complex micromodel described in [1]. The prediction of bacteria transport in such systems is challenging due to their complex swimming behavior within confined structures. Based on microfluidic experiments, we observe that motile cells tend to migrate into the dead-end pores unlike their non-motile counterparts, leading to higher retention of motile cells and consequent accumulation of biomass inside dead-end pores. To predict the observed behavior numerically, we simultaneously solve a set of Langevin equations for active elongated microswimmers. Simulation results agree well with our experimental retention curves. Further, based on the simulated trajectories we uncover how a motile cell migrates from a transmitting channel into a dead-end pore.

 

[1] Bordoloi, A.D, Scheidweiler, D., Dentz, M., Bouabdellaoui, M., Abbarchi, M. and P. de Anna, Structure induced vortices control anomalous dispersion in porous media,  2021 arXiv preprint arXiv:2112.12492
The direct and lagged responses of vegetation productivity to seasonal compound events
Authors: li jun , Bevacqua Emanuele , Chen Chi , Wang Zhaoli , Chen Xiaohong , Myneni Ranga B. , Wu Xushu , Xu Chong-Yu , Zhang Zhenxing , Zscheischler Jakob
Published: March 2022

Compound climate events can significantly impact vegetation productivity, yet the direct and lagged vegetation productivity responses to seasonal compound warm-dry and cold-dry events remain unclear. Using observationally-constrained and process-based model data, we analyze vegetation productivity responses to the compound conditions of precipitation and temperature in spring and summer. Our results show the regional asymmetries in direct and lagged effects of compound warm-dry events. In high-latitudes (>50°N), compound warm-dry events raise productivity. In contrast, in mid-latitudes (23.5-50°N/S), compound warm-dry events reduce productivity and compound warm-dry springs can cause and amplify summer droughts, thereby reducing summer productivity. Moreover, compound cold-dry events impose directly and indirectly adverse synergistic effects on productivity in mid-to-high latitudes and their effects exceed individual cold and dry impacts. Our results highlight that a multivariate perspective is necessary to appropriately investigate the impacts of climate extremes on vegetation productivity as precipitation and temperature often covary.