bluuebunny/crossref_metadata_2025 huggingface dataset:
Resilience of lacustrine phytoplankton community to the short-term river-to-lake water diversion
Authors: Dai Jiangyu , Wu Xiufeng , Wu Shiqiang
Published: March 2024

Cyanobacterial bloom induced by water eutrophication is one of the most serious ecological problems in freshwater lakes. Water diversion, transferring external freshwater into lakes, is proved to be the eco-hydraulic engineering measure rapidly relieving cyanobacterial blooms in eutrophic lakes. To explore the response of phytoplankton community to the changed aquatic habitat influenced by water diversion, we constructed the microcosm experiment modeling water diversion from Yangtze River to Lake Taihu in the laboratory, with one control group and three flow discharges groups of external freshwater from Wangyu River diversion channel during the summer water diversion period. Each modeling microcosm ecosystem had a volume of 5 L and was studied for a period of 20 days (10 days for the water diversion period and 10 days for the stop period). The results showed that the responses of physicochemical parameters in lake microcosms were sensitive, reflecting by the variations in contents of aquatic dissolved oxygen, total nitrogen, total phosphorus and dissolved silicate positively correlated with the flow discharges. During the period of water diversion, the cell abundances of Cyanophyta in all treat groups decreased significantly, while the abundances of Bacillariophyta increased, especially in the group with the highest flow discharge. The diversity and dominant species in phyla of Cyanophyta and Bacillariophyta were changed by water diversion and evidently in the highest flow discharge group. On the 20th day of the stop period, the relative proportion of Microcystis spp. recovered, and Pseudanabaena spp. became one of dominant cyanobacterial species in treat groups, which was related to the dominance of Pseudanabaena spp. in the external river water. The redundancy analysis between aquatic physicochemical parameters and phytoplankton communities revealed that variations in contents of aquatic dissolved oxygen, total nitrogen and dissolved silicate were the dominant environmental factors influencing lacustrine phytoplankton community in addition to the allochthonous inputs from external freshwater. However, the recovery of Microcystis spp. during the stop period of water diversion demonstrated that water diversion from Yangtze River to Lake Taihu has no sustainable effect on changing the dominance of Microcystis spp. in lakes in short time, although the diversity and phytoplankton community composition shifted during water diversion.
No consistent improvement in tropical Pacific sea surface temperature pattern in high-resolution climate models
Authors: Dhame Shreya , Olonscheck Dirk , Rugenstein Maria
Published: March 2024

Most of the coarse resolution Coupled Model Intercomparison Project (CMIP) climate models simulate a weakening of the equatorial Pacific east-west sea surface temperature (SST) gradient, contrary to the observation since the mid-1970s. Proposed reasons for this model-observation discrepancy are the equatorial Pacific cold tongue bias and the underestimation of equatorial trade wind strength in enhancing the upwelling in the central to eastern Pacific Ocean. Higher oceanic resolution has been known to improve eddy-induced heat transport, equatorial Pacific mean state SSTs, and precipitation. Here, we assess SST mean state biases and trend responses in a multi-model and multi-resolution ensemble from the High-Resolution Model Intercomparison Project (HighResMIP). Some models show an alleviation of the cold tongue bias in simulations of higher resolution compared to their respective low-resolution simulations, however, there is no consistent improvement across models in the trend response of the equatorial eastern Pacific SSTs at a higher resolution. Models are deficient in simulating the synchrony of trends and the causal relationships between surface zonal wind, SSTs, and thermocline structure in the eastern equatorial Pacific Ocean on multidecadal timescales. An underestimated ocean thermostat mechanism might explain climate models’ inability to simulate equatorial Pacific SST patterns since the mid-1970s. Simulating air-sea coupling correctly on multidecadal timescales in models might reduce the uncertainty of the projected tropical Pacific SST gradient.
Zinc leaching potential of environmentally friendly zinc sources obtained from spent batteries
Authors: Ortiz Castillo Raquel , Barragán Mantill Silvia Patricia , Gascó Gabriel , Méndez Ana , Sánchez Laura , Almendros Patricia
Published: March 2024

The use of highly effective sources of zinc in agriculture is necessary to achieve adequate crop quality and to avoid potential environmental hazards [1]. The use of synthetic chelating agents can lead to environmental risks such as contamination by leaching into aquifers [2]. There is currently a growing interest in the use of environmentally friendly zinc sources as an alternative to traditional ones [3]. This study focused on the evaluation of the leaching capacity of different Zn sources extracted from spent batteries with H2SO4 2M, H2SO4 0.25M or environmentally friendly complexes (glycine or citrate) in comparison with the traditional ZnSO4 source. Columns of 15 cm height and 1.5 cm diameter with 25 grams of washed sand were used for this. The treatment to carry 5 mg of Zn was added to each column and covered with another 5 g of sand. A flow of 10 ml/h of 0.01 M CaCl2 solution was added from the top of the columns. The leachates were collected in 20 ml portions until a total of 400 ml. The result showed distinct trends for the added treatments. The evolution of accumulated leached Zn for each of the treatments was fitted to the logistic model. The Zn-H2SO4 0.25M treatment achieved the highest percentages of total leached Zn at 400mL, accounting for more than 98% of the leached Zn with respect to the total Zn added to the columns. This percentage was statistically higher (P˂0.05) than the rest of the treatments, among which there were no significant differences in the total leached Zn, which reached percentages of between 72.68 and 77.12% (Zn-citrate and ZnSO4, respectively).Acknowledgments: This research has been funded by the Ministerio de Ciencia e Innovación y Universidades (MCIU), Agencia  Estatal de Investigación (AEI), and European  Union  “NextGenerationEU”  with grant number  TED2021-131198B-I00 “GREEN-AGRO-REC”.1.  Alloway, B.J. Zinc in Soils and Crop Nutrition; Second edi.; International Zinc Association Brussels, Belgium: Brussels, Belgium and Paris, France, 2008;2. Chandrika, K.S.V.P.; Patra, D.; Yadav, P.; Qureshi, A.A.; Gopalan, B. Metal Citrate Nanoparticles: A Robust Water-Soluble Plant Micronutrient Source. RSC Adv. 2021, 11, 20370–20379, doi:10.1039/d1ra02907j.3. Ortiz, R.; Gascó, G.; Méndez, A.; Sanchez-Martín, L.; Obrador, A.; Almendros, P. Comparative Study of Traditional andEnvironmentally Friendly Zinc Sources Applied in Alkaline Fluvisol Soil: Lettuce Biofortification and Soil Zinc Status. Agronomy 2023, 13, 4–15, doi:10.3390/agronomy13123014.
Impacts of intensive wetting, stagnation and drying cycles on carbon pools and allocation within stormwater processing system substrates designed for multifunctionality
Authors: Porter Lauren , Berger Nadja , Bucka Franziska , Egerer Monika , Kögel-Knabner Ingrid
Published: March 2024

Greening of our urban ecosystems provides a multiplicity of benefits, from the mood-lifting impact of nature-based aesthetics to the increased available habitat broadening the range of species within our densely packed cities. In recent years, greening efforts have largely been centered around the introduction of street trees, as their strong evapotranspiration effect mitigates increasing urban temperatures. However, the health and vitality of trees requires a significant amount of roadside space and are highly sensitive to stormwater dynamics as well as pollution, making implementation ill-suited in some urban spaces. Infiltration swales offer a practical, low-cost opportunity to counter-act the climatic increase in severe stormevents by purposely constructing substrates capable of processing polluted stormwaters and providing a habit for native plants to thrive. In testing high carbon organic amendments for their capabilities to adsorb road-side heavy metals and biocides as well as for their role in enhancing soil physical, chemical, and biological functioning - a mixture combining urban green waste compost with a high temperature biochar showed superior multidimensional functionality. In this follow-up experiment, informed substrate combinations are compared in their ability to support native plant diversity under cyclic flooded conditions across one growing season. An assessment is made on the potentials of carbon allocation to different pools between the plant, rhizosphere and bulk soil within this system. Results of this study hope not only to inform the scientific community but emphasize to city planners and officials the broadly interdisciplinary nature of soil systems, particularly the importance in pinpointing synergistic services as well as identifying those functions that may stand in opposition to one another. 
The potential of participatory citizen science in observing change in plastics in soils
Authors: Sandén Taru , Miloczki Julia , Götzinger Sophia , Hummer Philipp , Milewski Agnes , Spiegel Heide , Guggiari Dworatzek Mia Sol
Published: March 2024

In Europe, about 50 million tons of plastic are produced per year out of which ca 40% is processed into packaging (Plastic Europe, 2022). Packaging often ends up in landfill or in the environment after only a short or single use. Unfortunately, recycling is often inadequate, contributing to only about 10% of the European demand for plastic being met by recycled plastics (Plastics Europe, 2022). Large amounts of plastic end up in the oceans, accumulating as "garbage patches" and washing up on shores. However, the amounts of plastics that end up in soils is not precisely known. Scientific studies have concluded that 4 to 32 times as much plastic ends up in soils as in water bodies (Horton et al., 2017). In addition, little is known about what types of plastics enter the soil environment, and in what proportions.The Soil Plastic App allows citizens to input observations of visible plastics and their characteristics, with a strong focus on agricultural plastics, on soils and enable to monitor the change of plastics in soils. The App runs on the citizen science Spotteron Platform and is available for iOS, Android and as a web application. This way, observations can be entered anywhere on the globe and anytime. Since December 2022, citizens have already made over 22.000 plastic observations in the SoilPlastic App. The first set of validated Austrian citizen observations between beginning of April 2023 and end of July 2023 resulted in ca 6000 observations, as part of the Austrian Citizen Science Award Project Bunter Boden. This presentation will present the first results from Austria and discuss the potential of SoilPlastic App in observing change of plastics in soils.
Remotely sensing fruit presence and nutritional content in complex landscapes
Authors: Tiedeman Kate , Núñez Chase L , Alavi Shauhin , Schuerkmann Andreas , Crofoot Meg
Published: March 2024

An animal’s survival depends on its ability to successfully navigate a dynamic resource landscape that varies in space and time. To study animal cognition in ecologically-relevant scales and settings, there is a need for reliable and efficient measures of nutritional resource distribution and quality. Hyperspectral imagery leverages the differential surface reflectance to estimate the relative chemical composition of a pixel, and may therefore enable remote sensing the distribution of nutrients at the landscape-scale. To explore the potential of this method in wild settings, we used airborne hyperspectral imagery with ground-based field spectroscopy and high-throughput wet chemistry data to predict nutrients present across an apple orchard landscape in Ravensburg, Germany. In this pilot study, we collected data on 24 apple trees over a four week period preceding harvest. We used spectral samples taken on the ground with a field spectrometer to create a spectral library of leaf and fruit samples. Simultaneously, we flew a hyperspectral drone (Headwall CoAlign) to collect hyperspectral voxels that were then spectrally unmixed to determine the endmember abundance in each pixel. After predicting the presence of fruit in a pixel, we then used the relationship between fruit reflectance and the sugar content to predict the amount of sugar available within a pixel. Our results indicate that apple sugar content is correlated with lower reflectance of the fruit in the near infrared. We are able to predict fruit presence on a pixel basis with 85% accuracy, and to predict sugar content using individual fruit reflectance with 80% percent accuracy. From this information, we can then extrapolate to create a prediction of nutritional elements on a landscape. Our approach demonstrates strong potential for use as a means of remotely sampling the nutritional landscapes in which wild animals live. This will open exciting opportunities for ecological studies at the landscape scale, including animal behavior researchers and movement ecologists to test detailed hypotheses related to animal movement and decision-making.
Laser-driven stabilized cavity-enhanced absorption spectroscopy for HO2 detection near 1506 nm 
Authors: Ngo Minh Nhut , Nguyen-Ba Tong , Ghysels-Dubois Mélanie , Fittschen Christa , Schoemaecker Coralie , Chen Weidong
Published: March 2024

Cavity-Enhanced Absorption Spectroscopy (CEAS) [1-3], stands out as a cavity-based approach for sensitive measurement of sample absorption, without the need of complex optical setup and fast electronic devices for the used optical cavity compared to Cavity Ring-Down Spectroscopy (CDRS). CEAS offers continuous data acquisition within rapid scanning of laser frequency. The absorption spectrum is derived from the measured intensity outputs from the cavity with and without sample inside. While in tunable diode laser spectroscopy with wavelength modulation, the baseline is constructed of a high background signal, resulted from direct modulation of the laser power, superimposed with a small gas absorption signal. Achieving precise absorption assessments demands thus overcoming challenges in baseline structure, due to the laser intensity variation during laser frequency scan. Therefore, stabilization of laser intensity to maintain the baseline constant could improve the instrument's stability as well as measurement accuracy and precision.This work introduces the development and application of a laser Intensity-Stabilized Cavity-Enhanced Spectroscopy (IS-CEAS) operating near 1506 nm. The key innovation lies in employing an acousto-optic modulator (AOM) as an external power actuator for laser intensity stabilization. This strategy resulted in a remarkable 5-fold reduction in the laser intensity noise at lower frequency ranges where the integrated signal is detected. The fluctuations of cavity output intensity during laser scans were effectively eliminated, offering a baseline-free measurement of the absorption. This advancement notably bolstered system stability, enabling nearly 10 times longer integration than the conventional CEAS approach. The developed IS-CEAS system was employed to quantify the concentration of HO2 radicals produced in laboratory, yielding a bandwidth-normalized (1σ) limit of detection for HO2 at 1.6×108 molecule.cm-3.Hz-1/2. This value is comparable to the detection limits achieved by CRDS systems operating at the same wavelength.The experimental detail and the preliminary results will be presented and discussed.Acknowledgments The authors thank the financial support from the French ANR Foundation : ICAR-HO2 project (ANR-20-CE04-0003). This work has been partly supported by the EU H2020-ATMOS project, the ANR LABEX CaPPA (ANR-10-LABX-005) project and the regional CPER ECRIN program. References[1] M. Mazurenka, A. J. Orr-Ewing, R. Peverall, G. A. D. Ritchie. Annu. Reports Prog. Chem. - Sect. C 2005, 101, 100–142.[2] W. Chen, A. A. Kosterev, F. K. Tittel, X. Gao, W. Zhao. Appl. Phys. B 2008, 90, 311–315.[3] M. Ngo, T. Nguyen-Ba, D. Dewaele, F. Cazier, W. Zhao, L. Nähle, W. Chen. Sensors & Actuators: A. Physical 2023, 362, 114654
Variability of litter carbon stocks in Croatia
Authors: Bitunjac Doroteja , Ostrogović Sever Maša Zorana , Bakšić Darko , Anić Mislav , Marjanović Hrvoje
Published: March 2024

Litter stores around 5% of total carbon (C) stocks in the World's forests (Pan et al. 2011) and is one of five forest ecosystem C pools in national greenhouse gas (GHG) inventory reports, for which reporting is mandatory. Litter is known for its high spatial heterogeneity at different scales. Litter mass, and therefore its C stock, varies with respect to climate region, forest type, and various site and stand characteristics. Litter in the context of GHG reporting in Croatia corresponds to the forest floor (undecomposed leaf organic layer – OL, and fragmented and humified organic layer – OFH), while emissions and removals from the Forest land category, which includes the Litter pool, are stratified into Broadleaves and Conifers. Although a relatively small country in Europe, the biogeographical diversity of Croatia is high, which leads to the question if the existing stratification for the litter should be refined. We tested the hypothesis that litter C stocks within specific tree species groups (Broadleaves and Conifers) differ between biogeographical regions (BGR).From available national data sources, we compiled a database on litter, soil and forest stand variables at 276 plots distributed across three BGRs in Croatia: Alpine, Continental and Mediterranean. Litter data includes height, dry mass, C stock and C/N. Soil data includes soil organic C (top 30 cm), soil texture and bulk density. Stand variables include main tree species, stand basal area and tree density. Additionally, the database includes information on mean annual temperature (MAT), mean annual precipitation (MAP) and elevation at the plot level. Data were analysed at different scales regarding three BGR and two tree species groups (Broadleaves and Conifers).Litter C stocks showed high variability (CV>30%) at the regional scale, with the Mediterranean BGR having the highest variability (CV of 43%). When looking at the specific tree species group, coniferous forests in Mediterranean BGR have the highest averaged litter C stocks (8.13 tC ha-1), while the broadleaf forests in Continental BGR have the lowest averaged litter C stocks (4.37 tC ha-1). Litter C stocks significantly differ between Alpine and Mediterranean BGR in coniferous forests, while in broadleaf forests significant difference in litter C stocks was observed between Alpine and Continental BGR. Our results indicate that the stratification of the Litter with respect to BGRs may improve the accuracy of the national carbon inventory.
Interpreting Thermal Tracer Data in Carbonate Aquifers: Sensitivity Analysis and Identification of Ranges for Significant Heat Transfer Parameters
Authors: Glumov Oleg , Rastorguev Aleksandr , Klepikova Maria
Published: March 2024

With the increasing scarcity of resources and the drive to modernize and optimize conditioning systems, there is a growing interest in using aquifers as an energy source for both heating and cooling. The refinement of parameter ranges and sensitivity analysis enables enhanced modeling precision in heat transfer simulations. This research investigates heat transfer processes in a heterogeneous carbonate aquifer. Experimental data from a cross-flow thermal tracer test conducted at the Zvenigorod test site in 2016 were analyzed to determine the range of parameters. The study utilizes a dual-porosity model to represent the aquifer's properties. Heat transfer modeling is performed using a numerical-analytical approach that solves the filtration problem by superimposing the filtration flow velocities associated with pumping and injection wells (The Teis solution). The heat transfer problem is solved using the finite difference method. Interpretation of the experiment yields the ranges of the sought parameters, which were further refined through tracer tests conducted in 2021 using a doublet scheme at the Zvenigorod test site. Additionally, a sensitivity analysis of the parameters, namely rock block heat capacity (C), water-rock block heat exchange coefficient (λ), block shape correction coefficient (β), and average block power (mb), is conducted to investigate their interdependencies and influence on the modeling results. The obtained results contribute to a more accurate prediction of heat transfer in designing various environmental conditioning systems, water-to-water heat pumps, and other systems utilizing aquifers as a source of thermal energy.
Non-eruptive unrest and the role of magmatic brines, Vulcano, Italy.
Authors: Lupi Matteo , Alparone Salvatore , Palano Mimmo , Ricci Tullio , Finizola Anthony , Ursino Andrea
Published: March 2024

Although not all volcanic unrests lead to eruptions, it is generally accepted that magmatic activity is what causes volcanoes to awake. Alternatively, hydrothermal processes are often invoked to explain inflation and deflation dynamics. Magmatic brines have physical properties in between deep magmas and shallow hydrothermal fluids. Yet, to date we have no physical models accounting for geophysical signals that may be generated by the fluid flow of magmatic brines.Vulcano, the southernmost island of the Aeolian Volcanic Archipelago, Italy, entered into unrest in September 2021. The island experienced intense ground deformation,  fumarole temperature and gas emissions increases, and a marked augmentation of seismicity.For the first time since the deployment of broadband stations in 2005, very long period (VLP) seismic events were detected in the seismic records. Certain aspects of the geophysical signals recorded during the unrest are probably not fully compatible with traditional causal models involving fresh magma rising at depth or with a hydrothermal scenario.  In this contribution we discuss alternative scenarios and investigate whether fluid flow of magmatic brines may play a key role in understanding volcanic unrests.
Multi-annual nearshore evolution of a mega-nourishment in the southern coast of Namibia
Authors: Loureiro Carlos
Published: March 2024

Increasing pressures on coastal systems due to rising sea levels, extreme events, and human modification of coastal areas have led to accelerating erosion around many of the world’s coasts. Climate change and expanding coastal populations will worsen coastal pressures, creating a strong demand for engineering solutions that safeguard assets and infrastructure. Beach nourishment – the artificial placement of sand on the coast to increase the width and volume of a beach – is increasingly used as an engineering solution for sandy coasts, with  engineers and managers now focusing on mega-nourishments involving the placement of tens of millions of cubic meters of sand. As scale and complexity of nourishments increases,  the evolution of these highly modified coasts becomes more uncertain, particularly in areas where nourishments create strong disequilibria. In the southern coast of Namibia, diamond mining operations rely on the continuous seaward advance of the shoreline, achieved by artificial placement of large volumes of sediment along the coast. This can be characterised as a continuously prograding mega-nourishment, which over the last decades created the largest sandy beach accretion hotspot in the world. The complexity of such unprecedented shoreline advance, which is achieved through sediment discharge of unprecedented volumes of sediment in multiple locations using different methods, is further compounded by the very energetic wave climate that characterises the coast of southern Namibia, the variable bathymetric configuration of the nearshore that is masked by an apparent large-scale uniformity along the coast, and the notable variation in sediment characteristics, which range from fine sand to very coarse gravel and boulders. Analysis of regular nearshore bathymetric surveys performed since 2013 revealed variable morpho-sedimentary dynamics in this coastal system, with three main sectors with characteristic nearshore morphological change patterns. These range from progressive nearshore accretion in the northern section, despite significant local variation linked to morphological changes in nearshore bar systems, a strongly erosive nearshore in the central section where coarser sediment has been introduced, leading to changes in nearshore seabed composition that enhanced sediment transport potential due to hiding and exposure effects, and a southern section characterised by accretion in the upper nearshore and erosion in the lower nearshore, consistent with the redevelopment of an outer bar system, promoted by offshore-onshore transference of sediment. The variable morpho-sedimentary change patterns identified in the Namibian mega-nourishment provide novel insights regarding the nearshore evolution of highly dynamic and modified sandy coasts.
The spatio-temporally varying relationship between water yield and carbon storage services of larch plantation in the Liupan Mountains of northwest China
Authors: Wang Yanhui , Tian Ao , Yu Pengtao , Wang Yangfan , Wei Xiaocha , Wang Xiao , Liu Zebin
Published: March 2024

The water-carbon relationship in forests is complex and plays a crucial role in the provision of important ecosystem services, such as water yield and carbon storage. Understanding this intricate relationship is imperative for effectively managing the multiple services of forests. Therefore, a study was conducted to investigate the spatio-temporal variation of water yield and carbon storage as well as their relationship in larch plantations located in the semi-humid Liupan Mountains of northwestern China. The water yield data during growing season were calculated using the water budget principle, which involved subtracting evapotranspiration determined through long-term monitoring of hydrological processes from precipitation. Carbon density data were obtained by summing up vegetation carbon, humus carbon, and soil organic carbon (SOC) of 0-100 cm. These datasets were utilized to develop models that integrated the effects of key factors such as tree density, tree age, and elevation. Subsequently, these models were employed for predicting variations in water yield and carbon density while analyzing their relationship. The results indicate that the water yield initially exhibits a rapid decrease followed by a gradual decrease as tree density increases; additionally, it decreases initially and then increases with rising tree age and elevation. The carbon density shows an initial increase with rising tree density until a threshold, after which it declines; however, the limit of maximum tree density prevents stands with higher tree ages from reaching this threshold on more favorable sites. On other hand, carbon density consistently increases with rising tree age, and exhibits an initial increase followed by a decrease with rising elevation. Consequently, due to the combined effects of carbon density and water yield, their relationship displays a highly complex spatio-temporal variation pattern characterized by three distinct features: 1) A general variation mode exists in which there is a tradeoff relationship between decreasing water yield and increasing carbon density with rising tree density until a threshold, followed by a synergistic relationship where both services decrease; 2) Within this variation mode, the peak carbon density increases with rising tree age and site quality, while the range of water yield variation initially decreases and then increases with rising elevation; 3) However, on stands with higher age and better sites, the peak carbon density associated with the tree density threshold cannot be reached, resulting in only a tradeoff relationship existing. The multifunctional forest management aiming to achieve a balanced supply of dominant service (e.g., water yield in dryland regions) and other important services (e.g., carbon sequestration) should be improved by considering the complex water-carbon relationship.
Cloud condensation nuclei concentrations derived from the CAMS reanalysis
Authors: Block Karoline , Haghighatnasab Mahnoosh , Partridge Daniel G. , Stier Philip , Quaas Johannes
Published: March 2024

Determining number concentrations of cloud condensation nuclei (CCN) is one of the first steps in the chain in analysis of cloud droplet formation, the direct microphysical link between aerosols and cloud droplets, and a process key for aerosol-cloud interactions (ACI). Here, we present a new CCN dataset (https://doi.org/10.26050/WDCC/QUAERERE_CCNCAMS_v1) which combines aerosol modeling with observations to better explore magnitude, source, temporal and spatial distribution of CCN numbers. The dataset features 3-D CCN number concentrations of global coverage for various supersaturations and aerosol species covering the years from 2003 to 2021 with daily frequency.CCN are derived based on aerosol mass mixing ratios from the latest Copernicus Atmosphere Monitoring Service reanalysis (CAMSRA) in a diagnostic model that uses CAMSRA aerosol properties and a simplified kappa-Köhler framework which are suitable for global models. The emitted aerosols in CAMSRA are not only based on input from emission inventories using aerosol observations, they also have a strong tie to satellite-retrieved aerosol optical depth (AOD) as this is assimilated as a constraining factor in the reanalysis. Thus, this dataset is one of its kind as it offers lots of opportunities to be used for evaluation in models and in ACI studies.We will illustrate the distribution and variability of such derived CCN, evaluate them with observations and have a look at some specific features this dataset provides.Data description paper (preprint): https://essd.copernicus.org/preprints/essd-2023-172/
Remote estimates of sea surface nitrate from ocean color in the northwest Pacific 
Authors: Chen Shuangling , Wang Yuntao , Chai Fei
Published: March 2024

Sea Surface Nitrate (SSN) plays an important role in assessing new production and phytoplankton growth in the ocean, yet it has been challenging to estimate SSN from satellites due to its complex and varying relationship with different environmental proxies. The different SSN trends in the northwest Pacific reported in previous studies call for more detailed research to examine the interannual variabilities in SSN. We addressed this problem by developing a stacking-random-forest (SRF) based algorithm for Moderate Resolution Imaging Spectroradiometer (MODIS). It allows estimating SSN from daily sea surface temperature (SST) and Chlorophyll-a concentration (Chl) at a spatial resolution of 4 km. For SSN ranging between 0.0005 and 25.88 μmol/kg, the model had a root mean square difference of 1.34 μmol/kg (5.3%) and coefficient of determination of 0.92. Further independent validation and sensitivity tests demonstrated the validity of the algorithm in retrieving SSN. Using this novel data record, for the first time, we investigated the SSN interannual variabilities and trends from MODIS. Overall, the SSN showed a weak decreasing trend of -0.01±0.007 μmol kg-1 yr-1 (p < 0.05) in the northwest Pacific in 2002-2020, associated with an increasing trend in SST. The interannual variabilities of SSN were significantly correlated with the environmental proxies (SST, Chl) and the climate indices (Pacific Decadal Oscillation and North Pacific Gyre Oscillation). The SSN trends can be further restricted with more data available.
Multi-decadal harmonized records of globally gridded spaceborne fluorescence constrain estimates of terrestrial photosynthetic uptake
Authors: Levine Paul , Parazoo Nicholas C. , Bloom A. Anthony , Yadav Vineet , Madani Nima , Joiner Joanna , Yoshida Yasuko , Wen Jiaming , Sun Ying
Published: March 2024

Solar-induced fluorescence (SIF) is an important indicator of terrestrial photosynthesis and an increasingly targeted observable in spaceborne remote sensing. Here, we present results from efforts to harmonize data across multiple sensors in order to create long-term records that are suitable for multi-decadal analyses. Nevertheless, discontinuities in harmonized records and non-linearities in the relationship between SIF and gross primary production (GPP) demand the use of model enhanced approaches to bridge the gap between observed SIF and inferred GPP. Bayesian model-data fusion (MDF) provides an increasingly established and effective tool to reconcile different satellite datasets and systematically retrieve otherwise unobserved quantities (i.e., not directly measured by spaceborne sensors) such as biomass, leaf area, and GPP, and more accurately estimate interactions between carbon pools and changing climate.Here, we apply the CARbon DAta–MOdel fraMework (CARDAMOM) MDF system to (i) optimize the parameters and initial states of a terrestrial ecosystem model against global harmonized SIF datasets and ancillary vegetation products to constrain terrestrial photosynthesis and generate reanalyses of GPP, (ii) propagate uncertainty from SIF observations into the GPP reanalyses, and (iii) diagnose these reanalyses to examine the current and evolving state of photosynthesis with climate. Using two SIF products derived from OCO-2 and GOME-2/SCIAMACHY, respectively, we have produced two twenty-year reanalyses of global GPP at a monthly, 0.5-degree resolution. The variability of GPP in these products is well constrained by their respective SIF observations, and reproduces a significant fraction of the observed spatial and interannual variability from globally distributed flux towers. Our results provide a basis for further investigation of photosynthetic carbon uptake as a data product available for the research community.
Rock type as a driver of drainage network reorganizations in the Amazon region
Authors: Fadul Camila , Oliveira Pedro , Val Pedro
Published: March 2024

Drainage networks are responsible for water, sediment, and nutrient fluxes across landscapes. In the Amazon region, the freshwater system also houses an unparalleled aquatic biodiversity. Therefore, understanding the origins of drainage network reorganizations across variable spatial and temporal scales is fundamental for various disciplines. To elucidate the evolution of river systems in continent interiors, it is necessary to constrain the mechanisms that regulate the upstream propagation of base-level changes.  Features such as drainage captures, knickpoints, paleochannel and paleovalleys, wind gaps, and asymmetric drainage divides are widespread and have long been observed in the Amazon region. These features are typically thought to result from climate change or intraplate tectonics whereas the influence of rock type as a trigger is largely overlooked. In this study, we link the spatial patterns of landscape transience to lithologic variations in the Amazon Craton. Before their confluence with the Amazon River, the largest left-margin tributary systems exit the Amazon Craton and cross sedimentary rocks of the Amazon Sedimentary Basin (ASB). This lithologic transition is marked by an expressive escarpment formed over resistant sandstones of the basal units of the ASB. Through quantitative geomorphologic analysis of the topography, drainage divides, and rivers, we investigate if this sharp lithologic transition contributed to the observed patterns of drainage rearrangement. The results revealed that rivers with larger drainage areas, lower mean elevations, and that flow shorter distances over the resistant rocks systematically capture neighboring basins. We suggest that this pattern produces the observed ‘ladder-like’ topography where the smallest basins are perched at higher elevations and vulnerable to river captures and divide migrations. We argue that, as tributaries draining the shield respond to downcutting and/or base-level fall of the Amazon River, bedrock incision and knickpoint propagation are differentially slowed down by the resistant rocks according to their incision capacity, generating the observed systematic landscape transience. The observed widespread and systematic distribution of geomorphic transients suggests that lithology could be an important autogenic control of drainage network rearrangement in the Amazon region as well as in other post-orogenic landscapes. The protracted exhumation of resistant rocks in cratons and continental interiors offers an exceptional natural laboratory for studying landscape dynamics associated with rock type.
Laboratory experiments and numerical modeling of infragravity wave refraction and convergence on a reef platform
Authors: Su Shih-Feng , She Chia-Hsuan , Chen I-An , Weng Wen-Kai
Published: March 2024

Infragravity waves, characterized by water surface fluctuations between 25s and 250s, are generated from the release of long waves bound to short-wave group envelopes and temporal variations of breaking locations of these envelopes. On coral reefs, infragravity waves can dominate over short waves and control the processes of sediment transport and stability of reef islands/cay, particularly in combination with high tides and large wave events. A number of studies have investigated the development of infragravity waves in relation to a cross-section of reef shape, but few studies have attempted to address two-dimensional planar reefs, considering spatial and temporal variations in wave energy for sediment deposits on reefs. The study aims to characterize the variability of infragravity waves on a reef platform through a laboratory experiment and numerical modeling. The experiment was conducted in a 50m × 50m wave basin with a 1:200 scale reef platform model. The experiment was to quantify wave refraction, propagation from opposite directions through wave diffraction, and wave convergence on the reef platform under varying high swell energy. A wave-resolving wave model FUNWAVE-TVD, is employed to simulate swell and infragravity waves on the reef and the detailed wave hydrodynamics around the location of sediment deposits. Furthermore, the effects of wind stress on the development of infragravity waves on the reef platform are studied by the model incorporating a wind stress term. We also conduct a sensitivity study of wind drag parameterization to evaluate the effects of wind on the development of infragravity waves. These findings will provide crucial insights into accurate wave dynamics for predicting sedimentary processes and morphodynamics of reef platform islands.
Lyoluminescence: a potential tool for dating evaporites up to the Middle-Pleistocene?
Authors: Biernacka Magdalena , Kreutzer Sebastian
Published: March 2024

Lyoluminescence (LL) is light emission during the solvation of previously irradiated crystals in the liquid-solid interface (Atari, 1980). Our aim is the breakthrough development of lyoluminescence as a dating tool on halite (here: sodium chloride and potassium chloride) for application in Earth Sciences. The positive correlation between radiation dose and LL light emission makes crystal lattice defects viable natural ionizing radiation dosimeters. With a saturation dose of ~10 kGy (e.g. Atari et al., 1973) for sodium chloride dissolved in pure water and for realistic dose rates of ~4 Gy/ka (e.g., Han et al., 2014), the LL signal from salt minerals potentially may determine an age up to 2.5 Ma. We hypothesize that LL, naturally observable in salt minerals, will allow dating the last recrystallization event significantly beyond the age limits of conventional luminescence-dating methods. In the past, the potential of halite as a material for optical luminescence dating had been suggested, e.g. Bailey et al., (2000); Zhang et al., (2005). However, LL may offer an additional luminescence-dating tool for routine use in geochronology but targeting the crystallization instead of heat or light exposure event. Moreover, it may enable tapping into different archives and subsurface processes where only the event of the last hydration is of interest. In our contribution, we present the first basic design of a measurement prototype using 3D printing and preliminary experimental results of salts easily soluble in water.ReferencesAtari, N.A., 1980. Lyoluminescence mechanism of gamma and additively coloured alkali halides in pure water. Journal of Luminescence 21, 305–316. https://doi.org/10.1016/0022-2313(80)90009-5Atari, N.A., Ettinger, K.V., Fremlin, J.H., 1973. Lyoluminescence as a possible basis of radiation dosimetry. Radiation Effects 17, 45–48. https://doi.org/10.1080/00337577308232596Bailey, R.M., Adamiec, G., Rhodes, E.J., 2000. OSL properties of NaCl relative to dating and dosimetry. Radiation Measurements 32, 717–723. https://doi.org/10.1016/S1350-4487(00)00087-1Han, W., Ma, Z., Lai, Z., Appel, E., Fang, X., Yu, L., 2014. Wind erosion on the north‐eastern Tibetan Plateau: constraints from OSL and U‐Th dating of playa salt crust in the Qaidam Basin. Earth Surf Processes Landf 39, 779–789. https://doi.org/10.1002/esp.3483Zhang, J.F., Yan, C., Zhou, L.P., 2005. Feasibility of optical dating using halite. Journal of Luminescence 114, 234–240. https://doi.org/10.1016/j.jlumin.2005.01.009 
New paleointensity measurements of Apollo samples and implications for the lunar dynamo
Authors: Vervelidou Foteini , Weiss Benjamin P. , Nichols Claire I. O. , Murray Mary , Shah Jay , Lagroix France , McDonald Helena , Carvallo Claire
Published: March 2024

Spacecraft magnetic field measurements and paleomagnetic studies on Apollo lunar samples indicate that the Moon once sustained a core dynamo. However, strength and  duration of the dynamo field are key unknowns that may constrain the mechanism that powered it. Shedding light on these questions can improve our understanding about the generation of dynamos on small planetary bodies. Here, I will present new paleointensity measurements of the lunar magnetic field, based on alternating field and controlled atmosphere thermal demagnetization. In particular, we measured mare basalts and regolith breccias from the Apollo 16 and Apollo 17 missions, with ages ranging from 1.7 to 3.75 Gy old. I will discuss the results in the context of two issues surrounding lunar paleomagnetism. Firstly, I will show, through the example of an Apollo 17 mare basalt specimen carrying magnetizations acquired at two different epochs, that the magnetic record of these rocks is of lunar origin, as opposed to spacecraft or terrestrial contamination. Secondly, I will show results from the Apollo 16 regolith breccias suggesting that the lunar dynamo was fluctuating in intensity at least since 3.4 Ga. A fluctuating dynamo has been proposed as a possible resolution to the energy conundrum of the early phase of the lunar dynamo. Over a period of several hundred million years, extending up to 3.5 Gy ago, various paleomagnetic studies have inferred paleointensities that require an energy budget in excess of what numerical simulations, assuming a dynamo powered by thermochemical convection, estimate to have been available, given the Moon’s small metallic core. While our results do not directly address the energy budget conundrum during that time period, the fact that magnetic field fluctuations have occurred at least since 3.4 Gy ago, hints at the possibility that they could have occurred also at earlier times. If these fluctuations were large enough, they could allow for a reconciliation between paleomagnetic studies and numerical simulations, without the need to evoke alternative dynamo mechanisms.
Replicated stalagmite records revealed orbital and millennial-scale hydroclimate changes in arid central Asia across the MIS 5 stadial-interstadial transition
Authors: Liu Xiaokang , Wang Xianfeng , Shen Chuan-Chou , Li Hanying , Ruan Jiaoyang , Liu Guangxin , Yang Yan , Chen Fahu
Published: March 2024

Hydroclimate in arid central Asia (ACA) exhibited unique variability due to the dominance of mid-latitude westerlies over the Holocene, yet ACA climate variations during the last interglacial (Marine Isotope Stage (MIS) 5) remain elusive. Here, we present stable isotopes and trace elemental ratios of two coeval stalagmites in Xinjiang (northwest China), to address the orbital and millennial-scale climate shifts of ACA during MIS 5. The isotopic records of Baluk Cave (42°26' N, 84°44' E), spanning from 101.9 ka to 78.3 ka BP (before 1950 CE), show distinctly negative δ18O and δ13C values in the interstadials (i.e., MIS 5a and 5c), relative to the values in the stadial (MIS 5b). Such variations well correspond to the element data (X/Ca, X=Mg, Sr, and Ba), which exhibit values relatively higher in 5c and 5a compared with the 5b. These jointly suggest a key role of precession in orbital-scale climate evolution in ACA, closely following the insolation changes in warm-season (May to September) at 50°N.Specifically, the X/Ca ratios suggested relatively dry climate in 5c and 5a while wetter climate in 5b, supporting a ‘warm/dry and cold/wet’ pattern in ACA during the last interglacial. This pattern is further supported by the simulated precipitation variation using the CESM general circulation model. Moreover, the millennial-scale climate shift across the MIS 5b/5a transition is evidenced by depleted isotopic values in Baluk Cave (i.e., ~2.5‰ in δ18O and ~1.9‰ in δ13C), initiating at 87.2±0.5 ka BP and terminating at 84.1±0.4 ka BP. The onset and termination of this millennial event in ACA are comparable with those recorded by speleothems in eastern China and northern India, and with changes in northern hemispheric temperature, atmospheric methane and CO2 concentrations as inferred by the bi-polar ice cores. Our multi-proxy study suggests a close coupling between the large-scale westerly jet circulation, as suggested by δ18O, and local effective moisture in ACA, as documented by X/Ca, on orbital and millennial- scales.
Advective transport between the stratosphere and mesosphere
Authors: Zajíček Radek , Šácha Petr , Pišoft Petr , Mikšovský Jiří
Published: March 2024

The Brewer-Dobson circulation (BDC) characterizes the large-scale meridional overturning mass circulation influencing the composition of the whole middle atmosphere. The BDC consists of two separate parts - a shallow branch in the lower stratosphere and a deep branch higher in the middle atmosphere. The BDC is analytically usually defined as consisting of a diffusive part and an advective residual mean. Climate model simulations robustly show that the advective BDC part accelerates due to greenhouse gas-induced climate change and this acceleration strongly influences middle atmospheric chemistry and physics in climate model projections. A prominent quantity that is being studied as a proxy for advective BDC changes is the net tropical upwellling, commonly at the tropopause level or in the lower stratosphere. The upper branch of the BDC received considerably less research attention than its shallow part, although it features important atmospheric mechanisms. It couples the stratosphere and mesosphere and is responsible for a large portion of interhemispheric transport in the middle atmosphere. Aiming to fill this gap, we present a multi-model study of climatology and trends in advective mass transport across the vertically shifting stratopause. Results based on ensembles of 7 CCMI models include decomposition of long-term changes in cross-stratopause transport into individual terms such as acceleration of the residual circulation itself, vertical shift of the stratopause, changes in width of the upwelling region and changes in the shape of the stratopause.