bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate Change: Communicating What We Don’t Know
Authors: Stainforth David
Published: March 2024

When it comes to communicating climate change, both our understanding of what we don’t know and the uncertainties in the science are themselves core elements of our knowledge. That’s to say, what we know about uncertainty is part of what we know. Failing to communicate uncertainty and the limits of our understanding is failing to communicate the full picture of climate change.In 2023, after many years of writing, my book, “Predicting Our Climate Future: What we know, what we don’t know, and what we can’t know”, came out. The book is targeted at a public audience and addresses the many exciting, deep, conceptual and practical challenges that we face in climate change science and climate change social science. It aims to show that there are fundamental questions here that are simply fascinating in themselves: intrinsically interesting irrespective of the social relevance of the research.In doing this it has to shine a spotlight on the many things that we don’t know - particularly our limited ability to describe the climate of the future at local scales, and the consequences of climate change for the societies in which we live. Some might be concerned that doing this could undermine trust in climate science and work against our ability to tackle climate change. In practice the opposite is true. Acknowledging and presenting the limits of our knowledge upfront, increases the credibility of climate change information. It also provides a handle for people and diverse disciplines to actively engage with climate science and to bring their values and attitudes to risk into the debate.Of course it is also important to be clear about what we do know: what really isn’t open to debate and why. Here I will discuss how I approach this balancing act between communicating the exciting aspects of what we don’t know while being clear about what we do. I will also discuss my experience of presenting these issues to public, academic and business audiences. Further materials:Stainforth, D., “Predicting Our Climate Future: What we know, what we don’t know and what we can’t know”, Oxford University Press, 2023.(https://global.oup.com/academic/product/predicting-our-climate-future-9780198812937)Stainforth, D.A. The big idea: can we predict the climate of the future?, The Guardian, 30th Sept 2023(https://www.theguardian.com/books/2023/oct/02/the-big-idea-can-we-predict-the-climate-of-the-future)Podcast: Instant Genius - Can we predict the climate of the future?Podcast: Challenging Climate - Models and uncertaintyPodcast: Empty Space Inbetween - In conversation with David Stainforth
A Machine Learning Framework for Extending SMOS Surface Soil Moisture Observations over Canada
Authors: John Jeenu , Sushama Laxmi , Roose Shinto
Published: March 2024

Continuous and long-term surface soil moisture (SSM) data is essential for advancing the understanding of land-atmospheric interactions and climate change studies. Despite the contributions of different satellite missions in acquiring SSM measurements, the presence of data gaps poses a significant challenge. In this study, a machine learning (ML) framework is developed to expand the Soil Moisture Ocean Salinity (SMOS) SSM observations in both spatial and temporal domains over Canada. In the initial phase of the proposed framework, ML models, including random forest (RF) and convolutional neural network (CNN), are trained and validated using SSM-relevant climatic and geophysical variables extracted from the fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data (ERA5) for the 2011 to 2020 period and SMOS SSM for the same period as the target variable. While evaluating the developed models with unseen data from the years 2021 and 2022, the RF model shows slightly better performance when compared to that of CNN. The average root mean square error (RMSE) for RF is 0.0369 m3/m3 (Pearson correlation coefficient, R=0.94), while for CNN, the RMSE is 0.0494 m3/m3 (R= 0.89), with prediction biases mostly noted for regions with large inter-annual variability. Similarly, RF and CNN yield average RMSE values of 0.014 m3/m3 and 0.0635 m3/m3, respectively, when evaluated for spatial filling for the case of grid cells excluded during the training process. Hence, in the second phase of the proposed framework, the RF model is selected to extend the SMOS dataset for the 2008-2010 period. The temporal correlation analysis between the extended SMOS and Advanced Scatterometer (ASCAT) indicates reasonable correlations with values above 0.6, while the spatial correlation analysis reveals similar patterns between the two datasets, with smaller values for the summer season owing to the importance of local processes on SSM during this period. However, spatiotemporal extension of SSM to encompass surface types excluded during training remains a challenge and needs further studies. The developed framework holds the potential to address the spatio-temporal data gaps in other regions since both datasets are globally available.
Revisiting nonterminal hydrometeors: Refining instrument uncertainty
Authors: Larsen Michael , Vakhtin Andrei , Gomez Anthony
Published: March 2024

The fall velocities of rain and drizzle drops are often assumed to be a deterministic function of their size. These diameter-fall speed relationships are intrinsically assumed in the retrievals provided by some commercial rain measurement instruments (e.g. the Joss-Waldvogel Disdrometer (Distromet), Micro Rain Radar (METEK), and 1-Dimensional Video Disdrometer (Joanneum Research)).Some disdrometers are capable of independently measuring droplet size and fall-speed and provide evidence that not all drops adhere to the assumed size/fall-speed relationship. The ubiquity and magnitude of these deviations are still an area of some debate; clear identification of drizzle and rain drops falling at speeds different than their expected terminal fall velocities is muddied by conservative estimates of disdrometer resolution and performance. For a long time the bulk of observed non-terminal drop fall speeds were assumed to be instrumental artifacts and, even now, most investigators conclude drops falling at non-terminal speeds do not have a large impact on rain measurement science.To date, uncertainties in disdrometer-derived drop sizes and fall speeds have usually been derived from the manufacturer estimates. Here, we improve on these estimates by using a field calibration source (the new ``Large Drop Generator'' from Mesa Photonics) that permits user-selectable generation of droplets with known sizes and fall speeds. From these data, empirical estimates of disdrometer sizing and fall velocity bias and uncertainty can be determined. This, then, allows for a more reliable estimate of the fraction of non-terminal drops in natural rain and a more reliable assessment of the impact of non-terminal drizzle and rain drops in data derived from instruments that assume a specific drop size/fall-speed relationship.
On The Timing of Collision Induced Slab Break-Off and Polarity Reversal
Authors: Gün Erkan , Heron Philip , Pysklywec Russell , Topuz Gültekin , Göğüş Oğuz
Published: March 2024

The subduction process is the main driver of tectonic plate movements and can carry different-sized, thick crustal materials (i.e., continents, oceanic plateaux, seamounts, volcanic arcs) to the subduction trenches through the consumption of oceanic plates. The arrival of these allochthonous terranes to the subduction channel and their accretion to the overriding plate (fully or partly) can often halt the subduction process. Such a subduction-choking event is usually followed by slab break-off or polarity reversal if an ocean-ocean subduction setting is present. While these two types of post-subduction termination events are well-documented in the literature, their timing following a collision is often overlooked.Here, we present an extensive compilation of scientific literature that shows slab break-off and subduction polarity reversal (flip) events following a collision can happen in a very short time interval. Evidence from contemporary and paleo-subduction zones (i.e., Ontong Java Plateau, Taiwan/Ryukyu Arc, Banda Arc, Philippine Trench, Caribbean Oceanic Plateau, Central Apennines, India-Asia collision) suggests that these major subduction dynamic changes can occur, on average, in 2.5 to 4.5 Myr. The findings of our numerical subduction models are in accordance with the literature and demonstrate that the required time for collision-induced break-off and polarity flip can be as short as ~2 Myr. Our recent numerical modeling work, focusing on allochthonous terranes (microcontinents and oceanic plateaux), explains a potential mechanism for these fast geodynamic events. The slab pull force can stretch and weaken the trench side of drifting terranes. Following arrival in the subduction channel, this weakened portion of terranes is easier to break, yielding a fast detachment of subducting slabs.
Flood envelope curves for the estimation of design flood magnitudes for highway bridges
Authors: Maria Dona , Sushama Laxmi
Published: March 2024

The rising costs and safety concerns associated with flood-induced infrastructure damages in Canada underscores the critical need for adapting design flood magnitudes to future climate change. Creager flood envelope curves, which serve as the upper bound/limit of observed extreme flows for different drainage areas within a specific region, are widely employed by practitioners to estimate design flood magnitudes, which in the case of most river-crossing highway bridges is considered as 75-year flood magnitude. A framework for adapting Creager curves to future changes in streamflow is proposed in this study. To this end, Creager curves, for the current 1951–2020 period, are developed using regional frequency analysis (RFA) on annual maximum daily mean streamflow, considering 417 observation stations, located in seven major Canadian river basins (i.e., Fraser, Nelson, Mackenzie, Yukon, Churchill, St Lawrence and St John). The Creager coefficient C, which is the main parameter that defines flood envelope curves for different regions, under the current climate, exhibits considerable variability, ranging from 1 to 45, across the studied river basins.To adapt Creager curves for future changes, a correction factor, RC, defined as the ratio of future to current period C values is proposed. Two RFA approaches were employed to calculate the ratio using simulated streamflow data, derived using a cell-to-cell routing scheme, applied to an ensemble of five-member Regional Climate Model (RCM) GEM (Global Environmental Multiscale) simulated runoff for the current reference 1951–2020 and future 2021–2099 periods for the observation sites. The first RFA approach, considering only the GEM grid cells where the stations are located, suggests RC in the 0.3 to 1.6 range, with St John and St Lawrence River basins showing  values less than 1. The second approach, considering all GEM cells for a given region, produces comparable results but yields a wider range for RC and adds useful information in that RC values can also be established at ungauged locations, with RC values higher than 1.6 in various regions especially over western Canada. An evaluation of the level of confidence for RC , based on the GEM ensemble, reveal a higher level of confidence for most parts of the study domain. The second approach is likely to be a better choice for longer return periods considering the larger pooling of data. From a practical viewpoint, the proposed method for estimating future design floods is robust and transferrable to other basins but can benefit from using streamflow projections from other models for better quantification of uncertainty.
Unraveling Tasmania's Late Paleozoic Ice Age: Carbon Isotopic and Stratigraphic Signatures in Response to Glacial-Deglacial Cycles and Large Igneous Province (LIP) Events
Authors: Lestari Wahyuningrum , Al Suwaidi Aisha , Fox Calum , Vajda Vivi , Ceriani Andrea , Sun Yadong , Frieling Joost , Mather Tamsin
Published: March 2024

Late Paleozoic Ice Age (LPIA), which peaked during the mid Permian, resulting in widespread ice centers across Gondwana during its coldest periods. Assessing the climate change across this glaciation and the following deglaciation interval contribute important data not only in terms of understanding the end-Permian extinction event but also present-day global change. Tasmania, located in a high-latitude setting, forming a bridge between the continents Antarctica and Australia provides a valuable record of the environmental and climatic shifts that occurred in areas proximal to glaciation during the acme and waning stages of the LPIA.At the time of glaciation, Tasmania was a distinct landmass located within the Paleo-Antarctic Circle at a paleo-latitude of ~78°S. Here we present new high-resolution bulk organic carbon isotope analyses (δ13CTOC), mercury, bulk and trace elemental and sedimentological data combined with palynology and conodont biostratigraphy from the late stage (P3 and P4) of the LPIA Glacial-Deglacial Episode III. We base the data on samples from the Bicheno-5 core, from Eastern Tasmania, which contains approximately 83 meters of middle Permian glaciomarine sediments.Three negative carbon isotope excursions (CIEs) have been identified in the middle Permian (mPN1, mPN2, and mPN3). The latter two are correlated with the deglaciation episodes in Eastern Australia's glacial intervals P3 and P4 phases. Diamictites and dropstones are typically present in the sediments that record the most positive carbon isotope values, which likely correspond to the peak of the glaciation period. Elemental proxies indicate two cycles of increased weathering and terrestrial sediment influx to the marine system. These cycles coincide with the most negative carbon isotope values and are associated with deglacial cycles in Tasmania and within the paleo-Antarctic circle. The first deglacial cycle (mPN1) coincides with elevated mercury (Hg/TOC) which may hint at a link between deglaciation and volcanism, possibly from the Tarim III LIP.Comparisons with similar records from the marine Pingdingshan (PDS) section in South China confirms that our data from Tasmania reflect global carbon cycle perturbations providing new insights into the significant global climatic shifts that occurred during the middle Permian. The end stage of the LPIA offers a unique comparison to modern environmental and climatic change in Antarctica associated with anthropogenic global warming.
Determining the intensity of future heatwave episodes at urban scales: the case study of the Metropolitan Area of Barcelona
Authors: Ventura Sergi , Miró Josep Ramon , Segura-Barrero Ricard , Chen Fei , Martilli Alberto , Liu Changhai , Ikeda Kyoko , Villalba Gara
Published: March 2024

Given that cities concentrate more than half of the global population, it becomes crucial to assess the potential impacts of future climate change on cities. This study employs the Pseudo Global Warming (PGW) methodology to replicate recent heatwave (HW) episodes in the Metropolitan Area of Barcelona (AMB) under projected climate conditions until the year 2100. Initially, we identify all the HW events in the AMB over the past three decades (1991-2020) and simulate these HWs using the high-resolution Weather and Research Forecasting model (WRF) with the urban parameterizations BEP+BEM. Subsequently, the HWs observed in the last 30 years are replicated under mid-century (2041-2070) and end-century (2071-2100) climate conditions based on the SSP370 scenario. This scenario considers a future where greenhouse gas emissions and temperatures consistently rise, reflecting current climatic trends and geopolitical realities, including regional conflicts. Anticipated CO2 emissions are forecasted to nearly double from present levels by the year 2100.The contrast between recent and future HWs is examined not only in terms of temperature and relative humidity but also concerning the synoptic patterns responsible for generating HW conditions. The findings reveal a potential increase in geopotential height by up to 100 geopotential meters (gpm) by the end of the century, reaching values of up to 6050 gpm. Average maximum 2-m air temperatures are projected to rise by 2.5°C during the mid-century and 4.2°C by the end of the century. The most significant temperature anomalies (deviations from the mean temperature) are associated with persistent and stable synoptic patterns, which are projected to increase the most in frequency and intensity. The findings on relative humidity reveal a general decrease over the AMB, with a peak value of -16.2% in the west of the domain during the PGW-END.
Unveiling the springtime phenological strategies in permafrost vegetation
Authors: Zhu Yu , Lacroix Fabrice , Liu Lei , Zhao Dongsheng , Zaehle Sönke
Published: March 2024

The springtime phenology in permafrost regions of the Northern Hemisphere is exhibiting an extensive advance in response to climate change that is considered to be primarily driven by the rising temperature that vastly exceeds the average rate of global warming. This phenological trend emerges as the result of spatial variability in temperature and the response of vegetation to temperature (referred to here as the temperature sensitivity (ST) of phenology, change in phenological timing per unit change in temperature). In contrast to the more well-defined pattern of temperature variability, far less is known about the temperature sensitivity of vegetation phenology. Further, the above-average and highly heterogeneous warming in permafrost regions leads to changes in chilling exposure, frost risk, and other key controllers of temperature sensitivity, potentially allowing plants to adapt their phenological strategies. However, these phenological strategies  have not been investigated yet at the pan-Arctic scale in models or observations.Here, we seek to combine remote sensing-based and process model-based approaches to reveal the spatiotemporal pattern and strategic mechanisms regarding the ST of springtime phenology. To obtain generalisable dependencies, remote sensing retrieved phenology, climate data and soil physical property data are used to explore the linkages between ST and temperature and permafrost drivers, providing insights on vegetation phenological strategies. The novel QUINCY model is then adopted at site levels to validate the plausibility of possible strategies. Sets of model experiments with respect to varying biological and environmental factors are applied to elucidate the major controllers. Results shed light on the importance of environmental variability, and provide a more elaborate explanation for the ST variability of spring-time phenology.
The Quantification of Ultramafic Mine Waste Reactivity for Carbon Mineralization
Authors: Lu Xueya , Dipple Gregory
Published: March 2024

The urgent need for net-negative greenhouse gas emissions in the face of climate change is driving the global energy transition. Essential to this transition is the growing demand for critical metals, which leads to the need for more sustainable mining activities. Carbon mineralization via ultramafic-type minerals and tailings is one of the many strategies that can effectively reduce the carbon footprint associated with mining. The process involves the liberation of cations through dissolution and the subsequent precipitation of carbonate minerals to capture and store CO2 permanently. In this context, the rate and capacity of cation liberation are crucial, dictating the suitability of ultramafic mine wastes for carbon sequestration.Our earlier research focused on the characterization of 'labile cations,' derived from transient, early-stage dissolutions, which signify a critical aspect of the reactivity and carbon capture potential of ultramafic tailings. Labile cations, predominantly governed by mineral content, are essential for rapid and cost-effective carbon capture using these tailings. Despite recognizing the concept of labile cations, understanding the sources and controls of labile Mg in ultramafic minerals, rocks, and tailings remains limited. Moreover, there is a pressing need for the development of efficient, user-friendly, and cost-effective experimental, numerical, and technical tools. Addressing this, our study employs batch dissolution experiments and data science techniques, including Multiple Linear Regression (MLR) and Principal Component Analysis (PCA), to assess carbon mineralization reactivity. We report on the extraction of labile Mg from various sources such as serpentine, hydrotalcite group minerals, serpentinite, and ultramafic tailings, examining the impact of factors like grain size, ore heterogeneity, and brucite content.Mineral content is a primary control on labile Mg content. Interestingly, labile Mg content is quite variable within mineral groups. For instance, within the serpentine group, chrysotile and lizardite contribute notably higher Mg than antigorite. Likewise, the reactivity of hydrotalcite minerals is influenced more by the nature of their divalent and trivalent cations rather than by anion species. We also find that the original rock composition and mineral alteration progression are crucial in determining brucite abundance, serpentine type, and labile Mg accessibility. MLR and PCA analysis highlights the critical role of mineralogy and reactive surface area in predicting carbon mineralization reactivity. Overall, the results from this study offer significant advancements in the assessment of carbon mineralization potential in ultramafic mine wastes. These insights are instrumental in refining both ex-situ and in-situ carbonation strategies and extend their applicability to a broader range of alkaline solid wastes for CO2 capture and storage.
Providing a detailed glass geochemistry for key tephra layers of Lake Van, Eastern Anatolian Volcanic Province
Authors: Kearney Rebecca , Goff Jeremy , J. Schwab Markus , Neugebauer Ina , Smith Victoria , Appelt Oona , Günter Christina , Özdemir Yavuz , Karaoǧlu Özgür , Thirwall Matthew , Burfod Dan , Pickarski Nadine , Tjallingii Rik , Brauer Achim
Published: March 2024

The volcanoes of Nemrut and Süphan in the Eastern Anatolian Volcanic Province (EAVP) have been active throughout the late Quaternary, dispersing ash over wide areas. Numerous eruptions spanning the last interglacial to glacial period (130-30kya) are recorded in outcrops around the volcanoes and in the cores from Lake Van. A comprehensive tephrostratigraphy framework for the EAVP is an essential requirement for synchronising palaeoclimatic and archaeological records across the Mediterranean region. More information is required from the eruption deposits, including glass geochemistry on individual shards, and the stratigraphic order and precise ages for the eruptions.Here we present the findings of our detailed tephra investigation for the palaeoclimatic record of Lake Van (Turkey), as part of the TephroMed project. The lake is located close to both Nemrut and Süphan. Fourteen visible tephra layers (called V-layers) from Lake Van PALEOVAN ICDP record underwent geochemical characterisation by using major, minor (EPMA) and trace element analysis (LA-ICP-MS). New chemical analyses and 40Ar/39Ar ages of eruption deposits from proximal outcrops, provide detailed insight into the complex volcanic history of the EAVP, particularly of Nemrut. These results have revealed new volcanic origins for certain V-layers to Nemrut and Süphan, with tentative correlations between Lake Van’s fourteen V-layers to previously published dated proximal outcrops. Additionally, new glass geochemistry from dated proximal outcrops confirm the ages of the key eruption events associated with V-51 and V-18a of Lake Van. This improves the chronology of the Lake Van record and provides an understanding for the timing of complex eruptions from Nemrut and Süphan. The results are a major step forward to building a detailed tephrostratigraphic framework for the EAVP.
Identification of microbial influences on carbonate precipitation using dual clumped isotopes
Authors: Swart Peter , Lu Chaojin
Published: March 2024

The pioneering work of Judith McKenzie and her colleague Kerry Kelts identified the presence of dolomites associated with the oxidation of organic material in sediments obtained from the Deep Sea Drilling Project.  This discovery led to the wide spread recognition that dolomites form in association with microbial sulfate reduction.   Later Judy’s work proposed that the microbes were more than agents of creating a suitable geochemical environments, but actually were instrumental in precipitating dolomite.  This work stimulated the research of many, but the questions have always arisen as to what degree microbial processes are responsible for dolomite formation and other carbonate minerals in the ancient record.  Some have proposed different geochemical indices such as carbon or magnesium isotopes or the concentration of certain elements, maybe diagnostic of microbial processes.  However, these tools frequently provide equivocal evidence and therefore are not definitive. In this presentation we provide several examples of the use of a new geochemical tool, the dual clumped isotope proxy (Δ47 and Δ48).  Deviations from equilibrium, particular of Δ48 values, provide strong evidence of the influence of different mechanisms of the precipitation of dolomite and calcite.  In this presentation we present several examples in which the dual clumped isotope proxy has been employed.  These include not only dolomites, but also meteoric LMC calcite cements, previously believed to have form without the influence of microbial processes.  While the dual clumped proxy may also yield equivocal results, it will be a welcome addition to the tools used to understand the roles of microbes during carbonate precipitation. 
Diffuse He and H2 degassing survey for geothermal exploration at La Palma, Canary Islands
Authors: Melián Gladys V. , Furlan Matteo , Seefeld Malte , Martin-Lorenzo Alba , Gironés Ana , Pérez Nemesio M. , Rodríguez Fátima , Asensio-Ramos María , Padrón Eleazar , Hernández Pedro A. , Padilla Germán D. , Cartaya Sttefany , Arencibia Mónica
Published: March 2024

During geothermal exploration, the geochemical methods are extensively used and play a major role in both exploration and exploitation phases. Discovery of new geothermal systems at those areas where the resources are either hidden or lie at great depths, the geochemical methods for geothermal exploration must include soil gas surveys, based on the detection of anomalously high concentrations of some hydrothermal gases in the soil atmosphere. We report herein the results of an intensive soil gas study, focused on non-reactive and/or highly mobile gases such as helium (He) and hydrogen (H2), in Cumbre Vieja volcano, the volcanically ac tive part of La Palma island (Canary Islands, Spain). He has unique characteristics as a geochemical tracer: it is chemically inert and radioactively stable, non-biogenic, highly mobile and relatively insoluble in water. H2 is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas.A detailed geochemical survey was carried out in an area of 25 km2 at the western side of La Palma. A total of 766 sites were sampled at 40 cm depth using a metallic probe with 60 cc hypodermic syringes and stored in 10 cc glass vials for later laboratory analyses. Spatial distribution maps of diffuse He and H2 emission were constructed to study the presence of enhanced vertical permeability areas related to high temperature hydrothermal activity at depth. As a result, the main He emission anomalies show different size well-defined concentric-shape structures, distributed along a west to east main direction. On the other hand, H2 highest fluxes are slightly more dispersed in different areas, although some of the main ones are coincident with the distribution of the well-known anomalous volcanic CO2 active diffuse degassing in Puerto Naos and La Bombilla villages. Soil He and H2 surveys have demonstrated to provide meaningful insights of areas that could be acting as preferential zones of vertical permeability that allow deep source gases migration to surface and, therefore, of potential geothermal system structures.
Living among Artiodactyls - Current status and future plans of the Caravan dataset
Authors: Kratzert Frederik , Addor Nans , Shalev Guy , Gilon Oren
Published: March 2024

High-quality datasets are essential to support hydrological science and modeling. Several datasets exist for specific countries or regions (e.g. the various CAMELS datasets). However, these datasets lack standardization, which makes global studies difficult. Additionally, creating large-sample datasets is a time and resource consuming task, often preventing the release of data that would otherwise be open.About a year ago, we released the Caravan (as in “a series of camels”) dataset, a community initiative that consists of a large-sample hydrology dataset which is derived from globally consistent data sources, and
open source code that facilitates the creation of Caravan extensions to new regions by leveraging cloud computing on Earth Engine.
On release, the Caravan dataset included 6830 gauges from 14 different countries with daily streamflow records (median record length ~30 years), 9 meteorological variables (from 1981 - 2020) in different daily aggregations, 4 hydrological reference states, and a total of 221 catchment attributes.Since then, the dataset has been extended with several thousands of gauges in various, previously uncovered regions by different community members. Importantly, GRDC has joined the Caravan community effort and released a Caravan extension for 5357 watersheds (covering the period from 1950-2022) from the GRDC station catalog from 25 different countries. At this point, and with all extensions combined, the Caravan dataset now consists of 22494 gauge stations from 35 countries and contains a total of 660,382 years of streamflow records (median still at ~30 years).With this submission, we want to reflect in more detail on the current state of the Caravan community efforts and share our thoughts and ideas for the future of Caravan. Additionally, we welcome interactions with owners of hydrological datasets interested in contributing to Caravan and discussions with users of large-sample datasets to understand the needs and desires for datasets and inform our future efforts. All information on Caravan can be found at https://github.com/kratzert/Caravan/
Evaluation and Bias Correction of the ERA5 Reanalysis for Wind and Solar Energy Applications
Authors: Wilczak James M. , Akish Elena , Capotondi Antonietta , Compo Gilbert
Published: March 2024

The applicability of the ERA5 reanalysis for estimating wind and solar energy generation over the contiguous United States is evaluated using wind speed and irradiance variables from multiple observational data sets.  After converting ERA5 and observed meteorological variables into wind power and solar power, comparisons demonstrate that significant errors in the ERA5 reanalysis exist limiting its direct applicability for a wind and solar energy analysis.  Overall, ERA5-derived solar power is biased high, while ERA5-derived wind power is biased low.  Errors for the shortest duration, most extreme solar negative anomaly events are found to be statistically reasonably well represented in the ERA5, when completely overcast conditions occur in both ERA5 and observations.  Longer duration events on weekly to monthly timescales, which include partially cloudy days or a mix of cloud conditions, have ERA5-derived solar power errors as large as 40%.  ERA5-derived solar power errors are found to have consistent characteristics across the CONUS region.  The negative bias errors in the ERA5 windspeeds and wind power are largely consistent across the central and northwestern US, and offshore, while the eastern US has an overall small net bias.  For weekly to monthly timescales, the uncorrected ERA5-derived wind power errors approach 50%.  Corrections to the ERA5 are derived using a quantile-quantile method for solar power, and linear regression of wind speed for wind power.  These corrections greatly reduce the ERA5 errors, including for extreme events associated with wind and solar energy droughts, that will be most challenging for electric grid operation, while also avoiding potential over-inflation of the reanalysis variability resulting from differences between point-measurements and the temporally and spatially smoother reanalysis values.
A New Approach to Conduct End-Member Mixing Analysis in Catchment Hydrology and Hydrogeology
Authors: Liu Fengjing , Gierke John
Published: March 2024

End-member mixing analysis (EMMA) has been frequently applied to advance our understanding of hydrologic pathways, water sources, and surface water and groundwater interactions in catchment hydrology. Very recently, EMMA has been applied to hydrogeological systems to better understand groundwater recharge and movement. In conjunction with diagnostic tools of mixing models (DTMM), EMMA relies on eigenvectors extracted from coincident time series of geochemical and isotopic values measured at the same location to characterize the mixing space (numbers of end-members and conservative tracers), identify end-members, and quantify their contributions to streamflow and the groundwater system. However, this traditional approach limits the use of EMMA in many studies with small sample sets (short intervals). We hypothesize that EMMA can be extended to studies with infrequent sampling schemes if samples are collected from multiple scales or locations within a catchment by adding an additional mixing model assumption that end-members are consistent over varying scales. In other words, the underlying assumption means that only contributions of end-members vary with scales. This work uses two examples to demonstrate the success of EMMA for analyzing short-duration time series of water samples collected from multiple locations, one from a glacierized catchment in Bhutan and the other from a hydrogeological study in volcanic setting of El Salvador. The success was evaluated by independent tracers (not used in EMMA and also no direct connection with those used in EMMA) and semi-independent tracers (e.g., specific conductance (SC) and pH, which are chemically related to geochemical tracers used in EMMA). In the glacierized catchment, a three-end-member mixing model was developed using geochemical tracers for streamflow with contributions from glacier melt and direct precipitation, shallow groundwater (below and in front of glaciers), and catchment groundwater (base flow generated outside the glacierized area). The projections using the EMMA results and the measured values were very well correlated for independent and semi-independent variables, including SC (R2 = 0.97, slope =0.98, p < 0.001), pH (R2 = 0.70, slope =1.1, p < 0.001), stream temperature (R2 = 0.77, slope =0.6, p < 0.001), and δ18O (R2 = 0.90, slope =1.16, p < 0.001; not used in EMMA in this case). In the case of El Salvador study, three end-members were also identified for a number of groundwater wells, with direct precipitation and two types of groundwater from different geologic settings. The El Salvador model was validated using SC (R2 = 1.00, slope =0.97, p < 0.001) and sulfur (R2 = 0.87, slope =0.81, p < 0.01) that were not used in EMMA. The successful application of this new approach will significantly extend the application of EMMA to catchments that are difficult to access, or frequent sampling is impractical.
Idealized test cases in GFDL's FV3 demonstrating the new Duo-Grid.
Authors: Mouallem Joseph , Harris Lucas , Chen Xi
Published: March 2024

The Duo-Grid is a novel algorithm that addresses grid imprinting in generic gnomonic cubed-sphere grids. The algorithm aims to overcome grid discontinuities at the edges and corners by remapping data in a cube’s face halo region from its kinked coordinates to its natural location along extended great circle lines. We recently implemented the Duo-Grid in the Geophysical Fluid Dynamics Laboratory's (GFDL) Finite-Volume Cubed-Sphere Dynamical Core (FV3). We apply the Duo-Grid in idealized tests of 2D shallow water solver and the 3D hydrostatic and non-hydrostatic solvers. Our findings reveal that error norms are greatly reduced and grid imprinting is practically eliminated when employing the Duo-Grid. Most notably we find that a Rossby-Haurwitz wave is maintained significantly longer in the Rossby-Haurwitz tests, from about 80 to beyond 100 days. These results strongly suggest an improvement in FV3's accuracy and robustness.
Rising Temperatures, Rising Concerns: Early Summer and Sustainable Development in National Capital Regions of India
Authors: Mahato Susanta , Joshi Pawan K.
Published: March 2024

This study scrutinizes the impact of an anomalous early summer Land Surface Temperature (LST) surge on food security, energy dynamics, and human health in India's National Capital Region (NCR), and its implications for Sustainable Development Goals (SDGs). By analyzing MODIS images and employing Standard Anomaly (StA), monthly diurnal LST ranges were assessed. Results reveal March temperatures peaking from 23.11 to 41.57 °C, 3.5 °C above the average 21.78 to 39.41 °C range. Notably, contrary to conventional patterns, prolonged rain deficits drive this early summer warming rather than Sea Surface Temperature (SST). This warming adversely affects SDGs, significantly reducing crop yields, jeopardizing SDG-2's Zero Hunger target, impeding indicator SDG-2.4.1, and disrupting target 3.4.1 for health. Moreover, heightened energy consumption due to early summer warming disrupts SDG-6 on clean energy, directly impacting target 7.1 for electricity access. The findings underscore the urgency of addressing early summer warming's impact to progress toward achieving SDGs in India's NCR. Understanding and mitigating these effects are imperative for sustainable development initiatives in the region.
3D joint inversion of regional magnetotelluric, seismic, gravity and magnetic datasets to image lithospheric structure of Ireland
Authors: Molodtsov Dmitry , Kiyan Duygu , Bean Christopher
Published: March 2024

Regional gravity and magnetic surveys are essential sources of information about the structure and geodynamics of the lithosphere. However, geologically meaningful inversion of gravity and magnetic data usually requires integration with other geophysical methods. We have developed a 3-D joint inversion framework that has the flexibility of using independent inversion codes and model discretizations for each of the included methods, is easily expandable and supports a wide range of the coupling constraints. Here we show its application to the regional geophysical datasets available in Ireland. We present the results of joint inversion of long-period magnetotelluric data, seismic traveltimes, and land gravity – a multiparameter geophysical model of the crust and uppermost mantle of the whole Ireland. On a smaller scale, we present the results of joint inversion of gravity, airborne magnetic and magnetotelluric data for the Limerick Basin, focusing on imaging of a Carboniferous volcanic structure.  The main aim is to better understand the Pb-Zn mineral systems which are controlled by the tectonics of the basement and lower crust. Exploration-scale geophysical surveys and geothermal exploration will also benefit from the regional 3-D geophysical models.
Extremely large waves atop a depth-dependent background flow
Authors: Li Yan , Chabchoub Amin
Published: March 2024

A Nonlinear Schrödinger (NLS) equation-based theoretical model is derived in Li & Chabchoub (2024) for deepwater waves in the presence of a background flow. The flow propagates in the horizontal plane with its profile magnitude and direction being depth-dependent (see, e.g., Li & Ellingsen 2019). A new interpretation of the roles of Stokes drift, Eulerian return flow, and background vertically sheared current in the modulational instability (MI) of Stokes waves has been provided. The results in particular show that a current opposing a long-crested wave group can enhance the oblique modulational instability while suppressing completely the modulational instability which arises from sideband waves in the directions parallel to the wave group.  This provides clear physical insights into the roles of a background flow on rogue waves, owing to that the MI has been well recognized as a plausible cause to their generation. Moreover, the relevance of the background flow suppression or enhancement of the modulation instability process to the Craik-Leibobvich type 2 instability in the presence of Langmuir circulation is discussed and quantified. This relevance suggests a plausible physical mechanism for the energy transfers between waves and currents in the open ocean. References:Li, Y., Ellingsen, S. ̊A.: A framework for modelling linear surface waves on shear currents in slowly varying waters. Journal of Geophysical Research:Oceans 124, 2527–2545 (2019).Li, Y., Chabchoub, A.: How currents trigger extreme sea waves. The roles of Stokes drift, Eulerian return flow, and a background flow in the open ocean (2024). (submitted to Geophys. Res. Lett.).
Interpretable Early Warning Signals in Large Human Groups, using Machine Learning in an Online Game-experiment
Authors: Falmagne Guillaume , Stephenson Anna B
Published: March 2024

Understanding the emergent dynamics – in particular critical transitions – in complex social-ecological systems is key to foster positive social transformations in the Anthropocene era. Regime shifts in some ecosystems may be preceded by statistical early warning signals, but systems where such signals can be tested systematically are elusive. The r/place game hosted by Reddit is a social experiment that provides data for thousands of subsystems that can undergo critical transitions. It is therefore an excellent testbed for comparing the performance of various warning indicators. In r/place, millions of users collaborated to build many discernible drawings on a canvas of pixels. A drawing undergoes a transition when it is rapidly replaced by another. We build an early warning signal indicator that uses machine learning to combine the predictive power of a number of time-dependent and system-specific variables, and we show that its performance far exceeds that of standard indicators. For example, when training the algorithm and testing its performance on separate parts of the 2022 r/place, we detect half of the transitions coming in less than 20 minutes with only a 0.6% false positive rate. The performance only slightly decreases when training on 2022 data and testing on the 2023 experiment, showing that the predictive power holds across significantly different setups. We use SHAP values to elucidate the drivers of any given warning and highlight generic properties of warnings in online social systems. Some properties, such as a decreasing return time, are at odds with standard statistical indicators. Where sufficient data is available, our tool and resulting insights can contribute to warn of – and possibly trigger or avoid – macroscopic social and ecological change.
Understanding the influence of Atlantic Meridional Overturning Circulation interannual variability on European cold extremes
Authors: Alastrué de Asenjo Eduardo , Sillmann Jana , Baehr Johanna
Published: March 2024

Changes in the Atlantic Meridional Overturning Circulation (AMOC) impact the redistribution of heat across the climate system and can therefore influence surface temperatures over land. A large AMOC weakening, frequently analysed through idealised model simulations (e.g., freshwater hosing experiments), would lead to a strong cooling over the Northern Hemisphere. This cooling is most pronounced for winter months, suggesting a potential influence on cold extreme events; and for Europe, this influence has been hinted at. However, whether a more realistic interannual variability in the AMOC, rather than an idealised long-term weakening, also influences European mean temperatures and cold extremes is thus far unknown.To unravel this issue, we use the historical simulations of the 50-member MPI-ESM1.2-LR large ensemble, whose size is particularly suitable for analysing extremes. In these simulations, we categorise European temperatures based on their preceding interannual AMOC strengths. For yearly mean temperatures in a pre-industrial climate, we find that the distribution of temperatures following weak interannual AMOC strengths is significantly shifted towards colder values compared to years preceded by strong interannual AMOC strengths. Among all seasons, this shift is largest in winter; and spatially it is accentuated for northern latitudes. When considering present-day climate, the same shift still occurs, although less pronounced and strongest now for Eastern Europe. For daily extreme cold temperatures, the distribution of events is again colder following years of prevalent weak AMOC strengths; and this difference also becomes less clear and moves south-eastward in present-day climate. We complete the analysis by looking at the potential chain of physical atmospheric mechanisms that explains not only the connection between AMOC strengths and European extreme cold temperatures but also the evolution of this connection in the recent past.
The Green-Scorpion: a preliminary study on the potential amplification of physical climate financial risks by nature-related risks and feedbacks
Authors: Alvarez Jimena , Ranger Nicola , Freeman Anna , Harwood Thomas , Obersteiner Michael , Paulus Estelle , Sabuco Juan
Published: March 2024

Climate change and biodiversity loss are not happening in isolation. The erosion of natural capital by human activities will compound and amplify physical climate risks, and vice versa. We present new analyses that demonstrates that ignoring nature in physical climate financial risk assessment will lead to significant underestimates of the scale of the risks. This has implications for financial institutions and for the prudential policies of Central Banks and supervisors. We develop the first set of integrated climate-nature scenarios to explore the potential scale of physical risks, building upon the NGFS conceptual framework, alongside a global risk assessment approach that combines the ENCORE tool with global natural capital datasets and a multi-regional input-output modelling approach. We produce estimates of risks for five ecosystem services - surface water, ground water, pollination, air quality and water quality - across 7 sectors and 44 countries and 5 rest of world regions. Our analysis suggests that nature-related risks are material in scale, exceeding $7 trillion value at risk. Based on analyses of historical analogues and risk transmission channels we show that nature and climate risks are strongly interconnected and share characteristics in their potential for non-linear, cascading impacts. We propose a set of principles for scenario analysis and a framework for developing decision-relevant scenarios, including an inventory of almost eighty potential nature-related physical risk shocks (hazard-primary economic receptor pairs) that can form the basis to scenario development.