bluuebunny/crossref_metadata_2025 huggingface dataset:
Enigmatic Multi-Year Oscillations in Water Isotopic Composition of East Asia: Insights from a Subtropical Reservoir
Authors: Oza Harsh , Wang Chung-Ho , Liang Mao-Chang
Published: February 2023

A continuous bi-weekly water isotope analysis (δ18O, δD, and d-excess) was done since 2015 from a subtropical reservoir (Feitsui Reservoir) in northern Taiwan. The Feitsui reservoir is an important national freshwater system, as it provides water for the large urban population of Taipei. The isotopic data reveals a multiyear pattern and it closely follows the rainfall isotopic composition. We made a simple mass-balance model using the rainfall isotopic composition, inflow and outflow volumes, and meteorological parameters that fit well (R2 = 0.55; p-value < 0.05) with the observed isotopic composition of the reservoir. Based on this model, we estimated reservoir isotopic composition for the previous 20 years (2001-2021). The model also well reproduced a few years of historical data reported in the literature. In the model, we noted two conspicuous patterns: (1) multiyear cyclicity in δ18O and d-excess, and (2) a long-term enriching trend in δ18O. These patterns were not so obvious in rainfall because of the strong seasonality, which gets diluted in the reservoir because of the longer water residence time (~6 months). However, these patterns became visible in rainfall isotopes after removing the seasonal cycles. The observed multiyear patterns do not resemble with the known multiyear global processes, such as ENSO, PDO, and the East Asian Monsoon Index. However, the role of these global processes cannot be ruled out completely. We believe that because of the unique geographical location of the island, multiple moisture sources (South China Sea and central/northern China), dual monsoons (summer and winter monsoons), and complex hydrometeorological processes, the signals of these multiyear global processes get modulated and modified. The long-term enriching trend in δ18O seems to be a consequence of climate change. The enriching trend is more vivid during the winters than summers. This indicates the possible role of global warming and the expansion of the tropics because the Tropics of Cancer passes through central Taiwan. There also remains a significant knowledge gap in understanding the role of winter monsoons in East Asia. This study highlights the importance and the need for rigorous climatic research in Taiwan because of its unique location which makes it highly sensitive to climate change. This study may also have implications for paleoclimatic studies because it highlights the complex hydrometeorology of the region.
The algorithm of remote sensing thermal imagery calibration dedicated for UAV-based hydrological studies.
Authors: Szostak Radosław , Zimnoch Mirosław , Wachniew Przemysław
Published: February 2023

Remote sensing measurements of land surface temperature play a key role in the estimation of evapotranspiration. Thermal cameras used in Unmanned Aerial Vehicles are prone to errors manifested by fluctuations in temperature readings of the same object on different thermal images, vignette effect, and bias against the actual temperature. These problems were addressed with the calibration algorithm. It consists of two steps: i) georeferencing of images using EXIF data, key points matching, and global optimization of relative image positions with the gradient descent method; ii) calibration of temperature offsets occurring between images by correcting sequentially for differences between values on overlapping areas of adjacent images starting from single reference image. The calibration principle is based mainly on the observation that the temperature readings from two overlapping thermal images are shifted by an offset that is approximately constant for the entire overlapping area of the images. Thanks to the algorithm used, it was possible to increase the precision of the georeferencing of aerial images to a level that allows the direct creation of a mosaic of images without the photogrammetric software and reduce the standard deviation of the water surface and vegetation temperature measurements.Research was partially supported by the National Science Centre, Poland, project WATERLINE (2020/02/Y/ST10/00065), under the CHISTERA IV programme of the EU Horizon 2020 (Grant no 857925) and the "Excellence Initiative, Research University" program at the AGH University of Science and Technology.
Soil organic carbon in alpine environments under a warming climate
Authors: Udke Annegret , Zehnder Michael , Rixen Christian , Egli Markus , Hagedorn Frank
Published: February 2023

Climate warming is most pronounced in cold regions impacting plant-soil system with counteracting effects on ecosystem carbon storage. Whereas upward migration of plants (alpine greening) in a warmer climate potentially results in carbon uptake from the atmosphere and sequestration in the soil, increased decomposition at higher temperatures can enhance carbon release from the soil. Carbon losses from soils might be particularly high in soils where large amounts of carbon have accumulated under past climatic conditions. To infer soil organic carbon (SOC) changes of alpine soils in a warming climate, we assessed SOC stocks and their stability change along elevational gradients in the Swiss Central Alps. In our study, we excavated 21 soil pits to the parent material along elevational gradients (2000 to 3100 m a.s.l.) on three different bedrock types (calcareous, amphibolitic and siliceous) and analyzed their SOC stocks, stable isotope composition, and C stability by a soil incubation experiment. First results show a distinct elevation pattern with a strong decline in SOC storage with decreasing vegetation cover above 2700 m a.s.l.. However, soils on amphibolitic bedrock still contained substantial amounts of SOC even at elevations above 3000 m a.s.l. (0.8% SOC; >1.4 kg C/m2). As soils at this high elevation were buried under a few decimeter thick debris layer and no plants were present, it seems likely that these are remnants of fossil soils. In support, the buried soil organic matter (OM) had rather high δ13C values of -23.2‰ and narrow CN ratios of 10.7, indicating that they consist of strongly transformed OM. Analysis of their radiocarbon contents and CN analysis of stones will provide further information on the origin of these high elevation soils. Regardless of their origin, these soils represent a CO2 source. Soils released 0.2-0.5% of their SOC contents within one month upon incubation at 10 and 22°C in the laboratory. Moreover, in situ chamber measurements at the end of August 2022 showed a mean CO2 efflux of approximately 3.6 mg CO2-C/m2h to the atmosphere. Along the studied gradient, the δ13C values of surface soils strongly decreased with decreasing elevation. At the same time, the SOC mineralizability and soil C/N ratios showed a pronounced increase towards the soils at lower elevation having a dense grassland cover. This indicates that along with increasing SOC stocks, the contribution of relatively fresh OM with high turnover rates increases. Overall, our results show that there is a transition from the accumulation of SOC with alpine greening, reflected by alpine soils at lower elevations (< 2700 m a.s.l.), to buried SOC releasing C (possibly ancient C) at high elevation. Future measurements will provide further insight into the rapidity and magnitude of SOC stock changes in alpine terrain with ongoing climate warming. 
MultIO: Message-Driven Data Routing for Distributed Earth-System Models
Authors: Sármány Domokos , Geier Philipp , Valentini Mirco , Smart Simon , Hawkes James , Quintino Tiago
Published: February 2023

Traditionally, in numerical weather prediction, the computational cost of performing floating-point operations (flops) has been the primary concern. However, in the past couple of decades throughput to storage has become a significant bottleneck – a phenomenon often referred to as the input/output (I/O) performance gap. ECMWF runs time-critical operational weather forecasts four times a day, where the entire workflow of each run must complete within one hour. A single run currently produces around 30TiB of data, and it is expected to increase to hundreds of TiB within the next five-to-ten years. This is impossible on existing infrastructure without re-organising how model data is handled and processed. 

The proposed solution to this problem in the field of weather and climate numerical models has two elements. One is to decouple data output from numerical computations and dedicate pre-defined processes, called I/O-servers, purely to data output. The other is to move computations of derived (post-processed) data closer to the original “raw” weather data, thus reducing the amount of data to be moved. The challenge then is how to route the combination of raw and post-processed data efficiently to storage without compromising the performance of the running model. 

We present MultIO, an open-source software library developed at ECMWF for data routing from distributed parallel meteorological and earth-system models. It supports two distinct functionalities. First, it allows the creation of post-processing pipelines to calculate derived meteorological products, such as temporal pointwise statistics, interpolation onto different grids, encoding of data into output formats and output of data storage systems or other consumers. Second, it can act as an I/O-server, creating aggregated horizontal fields from distributed parallel meteorological and earth-system models. 

MultIO is a key component of the ACROSS project, funded by the EuroHPC JU. It is also partly developed via ECMWF's participation in Destination Earth and is a component of the Digital Twin Engine (DTE). 
Role of stratification in vorticity propagation throughout the entire water column: a Mediterranean example (Ionian Sea)
Authors: Giambenedetti Beatrice , Lo Bue Nadia , Artale Vincenzo , Falcini Federico
Published: February 2023

The Mediterranean is a climate change hot spot: it is warming 20% faster than the rest of the globe's oceans. Despite the importance of monitoring such dramatic changes and their consequences, the processes and the mechanisms involved in deep-sea variability are still unclear, due to a lack of long-term observations above 2000 m of depth. The availability of seafloor time series data and full-depth CTD profiles collected in the Ionian Sea allowed studying processes connecting the deep variability with the whole water column. The analysis of the in-situ seafloor time series showed a near-inertial peak in the current kinetic energy spectrum in the bottom layer, which hints at the presence of local vorticity. Moreover, the analysis of the CTD profiles revealed for the first time in this area the presence of variability at tidal periodicity in the deep layers (below 2000m), suggesting a connection with what was observed in the surface and subsurface layers. A unique opportunity to study and validate this mechanism was offered by the adjustment of the water stratification before and after the Eastern Mediterranean Transient, the major climate event occurred at the beginning of the 90s when warmer and saltier Aegean waters replaced colder and fresher Adriatic deep waters in the bottom layers of the Ionian basin. Data collected between 1999 and 2003 depict a stable water mass in the Ionian deep layers, identified as the Ionian Abyssal Water (IAW). The presence of the IAW layer could be a key condition for catching such variability in the deep. This allows studying the role that the stratification can have on the rapid propagation of the perturbation in depth, and also how the relative layer thicknesses and different densities can trigger the instability transport throughout the water column. The observed mean structure of the Ionian Sea stratification suggests that a 4-layer scheme should be enough to have a realistic yet straightforward theoretical representation. To study how much and under which conditions a potential vorticity input can propagate, a quasi-geostrophic equation has been considered, with 4 coupled layers of arbitrary thickness and density, simulated with a custom-designed algorithm. The relative stability of the coupled layers, and their response to external forcing, is crucial to understand how vorticity can propagate through the water column down/up and to/from the deepest layers. This case study aims to give more insight into how energy stored by the deep-sea layers can be released along the entire water column. This will enable a better parametrization of the deep processes also contributing to future Mediterranean climate numerical models.
New non-hydrostatic polar regional climate model HCLIM-AROME: analysis of the föhn event on 27 January 2011 over the Larsen C Ice Shelf, Antarctic Peninsula
Authors: Verro Kristiina , van de Berg Willem Jan , Orr Andrew , Landgren Oskar , van Ulft Bert
Published: February 2023

Recently, the climate version (HCLIM) of the regional numerical weather prediction model system ALADIN–HIRLAM of the ACCORD consortium, has been set up for the Arctic and Antarctic domains. Within the PolarRES project, HCLIM will be run, along with other regional climate models such as RACMO, MetUM, and MAR, to study the interactions between the atmosphere, oceans, and sea ice in the Arctic and Antarctic. For the Antarctic Peninsula, kilometre-scale horizontal resolution and non-hydrostatic model dynamics are essential to accurately resolve the complex topography and to capture small-scale processes such as the föhn winds that occur over ice shelves on the Antarctic Peninsula. Here, we present an analysis of the föhn event on 27 January 2011 over the Larsen C Ice Shelf, Antarctic Peninsula. The output of the non-hydrostatic HCLIM-AROME model, run at 2.5 km resolution, is evaluated against automatic weather station and radiosonde measurements and simulations of the non-hydrostatic regional climate model MetUM. We analyse the modelled air pressure, near-surface and tropospheric temperatures, wind speed and wind direction, and other atmospheric variables, demonstrating the strengths and weaknesses of the HCLIM-AROME model for this polar application. 
The changing gravity field due to a superplume under the Tharsis Region
Authors: Thieulot Cedric , Blasweiler Marjolein , Root Bart
Published: February 2023

The Tharsis Region has been an interest of study for many years due to its large impact on the long wavelength gravity field and topography of Mars. The leading theory on the origin of the volcanic region is a combination of both isostatic flexure of a thickened crust and a small contribution due to a (possible) large superplume residing in the upper mantle. The isostatic balance, on which previous studies have relied, does not adequately explain the long-wavelength gravity field spectra. These long-wavelength signals contribute to large scale features in the mantle. We consider the presence of a dynamic mass anomaly below the Tharsis Region. This could help explain the geological surveys of the relative young lava flows. By looking at mantle dynamic models we can explore the effect of a superplume that is actively rising in the mantle and changing the geoid over time. We ran a series of instantaneous axisymmetric finite element models of Mars with varying plume and subsurface structural variables constrained by InSight. We run the model for 50 years, thereby accounting for the total duration of satellite data acquisition. The deformation in the model allows us to calculate the change in dynamic topography and gravity anomaly.Our preliminary results show dynamic topography rates of a few centimetres per year and gravity rates in the order of 0.1 μGal per year. These gravity rates should fall within the precision of the Mars Reconnaissance Orbiter gravity field estimates, but are masked by other geological surface mass changes. Our results show that with longer and dedicated gravity observations, we should be able to observe the large scale mantle dynamics of Mars.
New insights into vintage 3D reflection seismic data in hard-rock environment
Authors: Hlousek Felix , Buske Stefan
Published: February 2023

The demand for reliable high-resolution reflection seismic exploration campaign in hard-rock environments increases continuously. The target of such surveys varies and covers e.g. mineral exploration, geothermal reservoir characterization or the exploration of potential nuclear waste deposit sites. Although the exploration targets are very different, the expectations on the seismic images and the challenges for data acquisition and processing are similar. The expected structures are often steeply dipping with varying strike directions and conflicting dip situations. Furthermore, the reflection seismic data often has to be acquired on land, possibly in populated areas, or in areas with severe accessibility restrictions. These limitations lead to irregular or sparse datasets in combination with sometimes low signal-to-noise ratio for the target reflections in the recorded data. Therefore, robust imaging methods are needed to generate high resolution reflection seismic images for such kind of data. Focusing prestack depth migration methods have proven to deliver improved image quality compared to standard time- or depth migration approaches. We show the results of our focusing pre-stack depth migration techniques applied to a vintage 3D seismic data set (ISO89) acquired in 1989 around the German deep continental drill site (KTB). We show a comparison to other previously obtained seismic images for the same data set and how the image quality evolved over time.
Global emissions of five controlled CFCs have increased since 2
Authors: Western Luke , Vollmer Martin , Krummel Paul , Adcock Karina , Fraser Paul , Harth Christina , Langenfelds Ray , Montzka Stephen , Mühle Jens , O'Doherty Simon , Oram David , Reimann Stefan , Rigby Matt , Vimont Isaac , Weiss Ray , Young Dickon , Laube Johannes
Published: February 2023

Production and consumption of ozone-depleting chlorofluorocarbons (CFCs) are controlled under the Montreal Protocol. CFC production for most applications was banned globally in 2010, albeit with exemptions for uses assumed to cause negligible emissions to the atmosphere, such as in the production of other chemicals. A few years ago, emissions of CFC-11 were reported to be increasing after their phase-out, most likely due to unreported production and non-compliance, which sparked widespread, renewed attention to this topic. Here we show that emissions of five other CFCs have increased since 2010, namely CFC-13, CFC-112a, CFC-113a, CFC-114a and CFC-115. Three of these CFCs are likely increasing due to their involvement in the production of non-ozone-depleting HFCs, which have largely replaced CFCs and HCFCs in many applications. The drivers behind the increase in the other two CFCs is unclear. While the impact of these CFCs on ozone layer recovery will likely be small, these long-lived CFCs are potent greenhouse gases and their CO2-equivalent emissions in 2020 were comparable to those of a mid-sized European country.
Snowpack, soil and forest energy budget and flux partitioning in boreal ecosystems
Authors: Nousu Jari-Pekka , Mazzotti Giulia , Ala-aho Pertti , Marttila Hannu , Launiainen Samuli , Cluzet Bertrand , Aurela Mika , Kolari Pasi , Lohila Annalea , Lafaysse Matthieu
Published: February 2023

The snow cover has a major influence on the wintertime surface energy budget. Accurate simulation of the snowpack energy fluxes is difficult due to limitations in the parameterization of turbulent fluxes under stable conditions and landscape properties (e.g. canopy and topography) that complicate the radiation budget. In fact, description of turbulent fluxes is subject to major uncertainties in snow modelling, and simulating snow in forests is critical for hydrological and climate modelling. Yet, detailed studies that evaluate the models with surface energy flux observations at high latitudes are rare. In this study, we evaluate components of the SURFEX land surface model on four eddy covariance sites in Finland. These sites cover two different climate and snow conditions, the southern and northern subarctic zone, and two different boreal landscape types, peatland and forest. On the peatland sites, we evaluate the sensitivity of simulated surface energy fluxes and snow conditions to different process parameterizations (e.g. snow processes and turbulent exchange) implemented in the detailed snowpack model Crocus. On the forest sites, we examine alternative approaches to represent the energy and mass budgets of the soil and vegetation with the ISBA and MEB models, and assess their performance in simulating energy fluxes, snow conditions and soil thermal regimes. We show that the turbulent fluxes under stable conditions simulated by the default stability correction function do not match the observed values, and thus, it is necessary to increase the simulated turbulent exchange under stable conditions. Moreover, we demonstrate that explicit vegetation is required to concurrently simulate accurate surface heat fluxes and snow/soil conditions in forests. Our results have larger implications for choosing suitable model parameterizations and structures depending on the use case of interest.
The impacts of future climate change on water security in the Mediterranean Basin
Authors: Eekhout Joris , de Vente Joris
Published: February 2023

The Mediterranean Basin is classified as one of the hot-spots for climate change, where a significant decrease of precipitation and an increase of temperature are expected. This will most likely lead to a redistribution of water within Mediterranean catchments. However, the scale and magnitude and spatial differences of the impact of climate change on water security across the Mediterranean is still uncertain. Here we present the preliminary results of a systematic review on the impact of climate change on water security in the Mediterranean Basin. In this systematic review we focused on studies performed in the Mediterranean Basin that apply a hydrological model forced by climate model output and report changes in blue and/or green water, i.e. water stored in rivers and reservoirs (e.g. runoff or reservoir storage) and water stored in soils (e.g. groundwater recharge). The variables obtained from the studies include variables related to study area, climate and hydrological models, and model output. Our preliminary results show that the general tendency is a decrease of precipitation and an increase of temperature, which will cause a decrease of projected blue and green water. This will have serious consequences for the potential of irrigated agriculture, industry and household water use in the Mediterranean Basin, which heavily rely on the availability of blue water. But also for rainfed agriculture, where a decrease of green water may force farmers to abandon their land or transform to irrigated agriculture.We acknowledge funding from the Spanish Ministry of Science and Innovation (AEI) (PID2019-109381RB-I00/AEI/10.13039/501100011033).
Influence of Indian Summer Monsoon on the Post-Monsoon Cyclones
Authors: Francis Feba , Kushwaha Vikas , Karumuri Ashok
Published: February 2023

The North Indian Ocean (NIO) has two Tropical cyclone (TC) seasons, i.e., pre-monsoon and post-monsoon. We find that the Indian summer monsoon (ISM) has an influence on the frequency of cyclones in the post-monsoon in the NIO. Flood years show a higher frequency of TCs, and drought years show a lesser frequency of TCs than normal years. By the examination of Grey-Sikka parameters for cyclogenesis, we show that during the drought years, the mid-tropospheric humidity, low-level vorticity, and Tropical Cyclone Heat Potential are lower than in normal years and the vertical shear is higher over most of the NIO. These factors lead to the reduced cyclonic frequency in the Bay of Bengal during drought years and more frequent cyclones in flood years, though the relation is more ambiguous in the Arabian Sea. This study builds an unexplored relation between ISM and TCs in the NIO and would help in improving TC seasonal prediction.
The nature of runaway precipitation and consequences for the safe applicability of OAE
Authors: Suitner Niels , Faucher Giulia , Lim Carl , Riebesell Ulf , Hartmann Jens
Published: February 2023

To ensure a safe and efficient application of Ocean Alkalinity Enhancement (OAE) it is crucial to investigate its impact on biogeochemical systems. While various theoretical studies have shown promising results, there has been a lack of practical research to test the applicability of this technology in natural environments. Recent studies by Moras et al. (2022) and Hartmann et al. (2022) described the effect of runaway precipitation in the context of OAE. During this process Ca-carbonate formation is triggered, leading to a loss of the initially added alkalinity and counteracting the whole idea of OAE.At a field campaign at the Espeland Marine Biological Station (Bergen, Norway) we examined the characteristics of runaway precipitation by using local natural seawater and storing the reactor bottles in a flow-through incubation chamber, mimicking the real-time temperature and light conditions of the Raunefjord. Conducted lab experiments lasted between 20-25 days, and tested CO2-equilibrated and non-CO2-equilibrated addition of alkalinity. The temporal development of the carbonate chemistry parameters was monitored after alkalinity addition and the triggered Ca-carbonate precipitation process was described in detail. We found that above upper critical limits of alkalinity addition in natural seawater, immediate precipitation prohibited an enhancement to higher alkalinity levels.  Our results could be helpful to guide the definition of upper limits of alkalinity for the safe and efficient application of OAE in an open sea scenario. In addition, the precipitates were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy, to characterize the formed particles and follow their growth patterns.Hartmann, J., Suitner, N., Lim, C., Schneider, J., Marín-Samper, L., Arístegui, J., Renforth, P., Taucher, J., and Riebesell, U. (2022). Stability of alkalinity in Ocean Alkalinity Enhancement (OAE) approaches – consequences for durability of CO2 storage, Biogeosciences Discuss. [preprint], https://doi.org/10.5194/bg-2022-126Moras, C. A., Bach, L. T., Cyronak, T., Joannes-Boyau, R., & Schulz, K. G. (2022). Ocean alkalinity enhancement–avoiding runaway CaCO 3 precipitation during quick and hydrated lime dissolution. Biogeosciences, 19(15), 3537-3557, https://doi.org/10.5194/bg-19-3537-2022
Limit global warming to 1.5 oC will alleviate the synchronous failure of maize yield in China
Authors: Liu Shengli , Xiao Liujun
Published: February 2023

Extreme weather and climate events (EWCEs) have jeopardized crop yields globally. The evidenced increasing trends of EWCEs would amplify their impacts if they co-occurred. This would bring additional shocks to global food markets, and result in severe risks to food security. A systemical analysis of the risk of crop yield failure under EWCEs and their changes in a warming future is essential to guide adaptations adequately and ensure food security. In this study, we compared the relations between maize yield anomalies and 14 climatic indices over the growing season in the breadbasket (10 provinces) in China during 1981-2018 to identify the main EWCEs determining maize yield anomalies. We then compared the probabilities of crop yield failure under current climatic conditions and its projected changes under 1.5 and 2.0 oC global warming using 28 climate models from CMIP6. The result shows that the maize yield anomalies can be mainly explained by extreme temperate-related indices, despite the various indices for individual provinces. The probability of synchronous yield failure in 1981-2018 was below 7.5% when we randomly summed up seven maize provinces among ten. The probability may reach 2.45% and 7.73% on average under 1.5 and 2.0 oC global warming conditions for all ten provinces, respectively. The transferred risk of crop yield failure revealed that more current maize land would be outstripping its climate-safe space under warmer conditions. Our results highlighted the benefits of limiting global temperature rise within 1.5 oC. Furthermore, enhancing crop resistance to adverse climate situations through appropriate adaptations would be a promising solution to stabilize crop productivity.
There and back again: Combining hydrogen and strontium isotopes refines the trans-Saharan migratory patterns of the butterfly Vanessa cardui
Authors: Reich Megan , Ghouri Sana , Zabudsky Samantha , Talavera Gerard , Bataille Clement
Published: February 2023

Migratory insects serve an important role to ecosystems and economies as they participate in the long-distance transfer of nutrients, pollen, and biomass. However, migratory insects are understudied, especially compared to birds and mammals, partially because traditional tracking techniques (e.g. mark-recapture, biologgers) are often ineffective for insects because insects are small, short-lived, and numerous. Thus, isotope geolocation has become an effective tool for studying dispersing insects. The painted lady butterfly (Vanessa cardui (L.)) is a virtually cosmopolitan species that was recently found to make regular, annual multi-generational migrations across the Sahara Desert. Previous work geolocating painted ladies with hydrogen isotopes has shown early spring migratory movements of painted ladies from sub-Saharan Africa to Mediterranean Europe and autumn movements to the sub-Sahara from Europe. However, these previous works using hydrogen isotopes were unable to offer refined estimates of natal origin due to the inherent limitations of the technique. Here, we update previous hydrogen isotope-based geographic assignment by (1) using an updated model of hydrogen isotope variations across the landscape (i.e., isoscape), (2) combining with strontium isotope-based geographic assignment, and (3) expanding the number of geolocated butterflies to include capture locations on both sides of the Sahara Desert across different years. Using this method, we spatially refine previous estimates of the natal origins of successful trans-Saharan migrants and estimate the distances that successful migrants travelled. Overall, this study demonstrates the advantages of combining hydrogen and strontium isotopes for the geographic assignment of migratory butterflies and further advances our understanding of long-distance insect migration.
Effects of different uncertainties on optimal policies
Authors: Martinez Montero Marina , Crucifix Michel , Brede Nuria , Botta Nicola , Couplet Victor
Published: February 2023

Decisions are usually taken sequentially in climate change policy: every certain amount of years, new agreements and promises are made about greenhouse gas emission reduction etc. In the intersection of decision theory and climate science, sequential decision problems can be formulated and solved, to find optimal sequences of policies and support policy makers with some advice.There are, however, many uncertainties affecting the outcome of these optimisations. Since these decision problems tend to be very simple in comparison with the complexity of the real world, knowing how different uncertainties affect optimal policies might be more important than what the optimal policy comes out to be. In this work, we explore how some uncertainties affect optimal policies and the possible trajectories associated with those optimal policies.   For this aim we formulate a sequential decision problem with a single "global" policy maker. The decision problem starts with the world state in 2020 and decisions are taken every 10 years till 2100. The policy maker has options regarding CO2 emissions reduction, geoengineering in the form of solar radiation modification and carbon dioxide removal.We simulate the effects of the decisions on the world’s state with SURFER. SURFER is a simple and fast model featuring a carbon cycle responsive to positive and negative emissions, it allows for geoengineering and accounts for sea level rise from ice sheets (containing tipping points) and from ocean expansion and glacier melt. SURFER has been shown to reproduce the globally averaged behavior of earth system models and models of intermediate complexity from decades to millennia. As opposed to some optimal decision problems in the context of climate change which use integrated assessment models of the climate and the economy, here, with the aim of transparency and simplicity, we consider only a climate model. We define a modular and transparent cost function that contains what the policy maker cares about. This function is a linear sum of costs associated with: green transition, geoengineering use and risks, temperature and ocean acidification damages and long term sea level rise commitments.Using this decision problem we investigate how different kinds of uncertainties affect the sequence of optimal policies obtained and the optimal trajectories associated with those optimal policies. We consider three different kinds of uncertainties: uncertainties in the priorities of the decision maker (i.e., in the reward, cost or utility function), uncertainties on some physical parameters (in particular, climate sensitivity and ice sheet tipping points) and political uncertainty (policymaker’s decisions may not be implemented). 
Development and use of an integrated modelling approach to simulate dynamic risk profiles and support risk reduction strategies
Authors: van Delden Hedwig , Vanhout Roel , Jeanneau Amelie , Radford Douglas , Maier Holger R. , Zecchin Aaron C.
Published: February 2023

Natural hazards pose a significant risk to societies across the world. This risk will likely increase in the future, due to climate change, urban development and changing demographics. Understanding the range of potential future conditions, and the associated key uncertainties, is essential in designing disaster risk management strategies that holistically account for these drivers.For this purpose, we have developed a spatially explicit, dynamic, multi-hazard decision support system called UNHaRMED, which calculates dynamic risk profiles as a combination of hazard, exposure and vulnerability. The aim of UNHaRMED is to better understand current and future risk, and assess the impact of (a combination) of risk reduction options under various  future conditions. In order to do so, UNHaRMED consists of coupled models integrated into a policy support system. It allows the user to understand the impact of climate change, socio-economic developments and risk reduction options on the future evolution of exposure, hazard and vulnerability and hence the resulting risk.Use of the system will be illustrated through an application to a region in Australia for wildfire and flood risk, for which we simulated a range of futures using different climate and socio-economic scenarios. We found that in a rapidly growing area, the impact of socio-economic development exceeds the impact of climate change, and well thought out spatial planning strategies can substantially reduce future wildfire and flood risk.The application of UNHaRMED showcases its potential in better understanding future uncertainties and leveraging this information to assess the impact of risk reduction options under a range of conditions. Lessons learned from this can then be incorporated in the design of robust and/or adaptive risk management strategies.
What limits carbon sequestration in soils?
Authors: Don Axel , Schneider Florian , Heinemann Henrike , Seitz Daria , Begill Neha , Poeplau Christopher
Published: February 2023

Carbon (C) sequestration in soils has been discussed as important climate mitigation option with the potential to generate negative emissions. Agriculture requires such negative emissions since some of their greenhouse gas emissions are unavoidable and require compensation to achieve net zero. Expectation of soils contribution to climate mitigation need to come down from theoretical assumptions to realistic estimates. In order to do so the limitations for soil C sequestration need to be analysed and discussed. Here we present a framework with case studies looking at limitations that are i) intrinsic due to the soils´ ability to stabilize SOC on mineral surfaces (C saturation) and the current state of high SOC stocks ii) constraints by net primary productivity and biomass availability, and iii) restrictions due to limited land area and increasing global demand for food, feed and fibre from agricultural production. For the start of this analysis we used data of the first German Agricultural Soil Inventory comprising more than 3000 sites. In total 34% of agricultural topsoils (0-10 cm depth) in Germany contain high SOC stocks with more than 4% soil organic matter. In particular soils with ground water influence and grassland land-use contain high SOC stocks, which need to be maintained first before further SOC accumulation can be achieved. C saturation was frequently discussed as reason for preventing further built up of stabilised SOC in C-rich soils. However, based on data from long-term field experiments and the national soil inventory we challenge the perception that C saturation is a limiting factor for soil C sequestration in our soils.Biomass is required to maintain and enhance SOC. However, the quality and form of biomass influences the effectiveness for SOC formation. Roots are more important than above ground biomass. This shifts the view of C-management to below ground. Above ground biomass, such as straw, maybe harvested without harms to SOC stocks and used in industrial processes or converted to biochar. Strongly limited is the land area on which measures for SOC built-up can be implemented without compromising other ecosystem services. Avoiding leakage of greenhouse gas emissions due to measures for SOC sequestration are a major challenge. With the example of cover crops as agricultural management option we illustrate these limitations and discuss how some of the limitations for SOC sequestration could be removed.
Robot-aided autonomous hyperspectral mapping in mining environments
Authors: Lorenz Sandra , Kirsch Moritz , Fuchs Margret , Thiele Sam , Gloaguen Richard
Published: February 2023

Geological face mapping is a frequently recurring task in mining operations, the results of which have an immediate influence on the mines’ profitability, safety, and environmental impact. Hyperspectral imaging is an increasingly applied technology to improve the efficiency and accuracy of mapping tasks. The rapid and non-destructive acquisition of spectral material properties allows meaningful material information such as mineralogical surface composition to be obtained in a safe and efficient manner. The fusion product of backprojected hyperspectral data with 3D surface information (so-called “hyperclouds”) further enhances the data value by enabling easier data correction, integration, and implementation into digital archives and models. Mining environments, however, remain a challenge for operational hyperspectral mapping, particularly underground where inadequate lighting, access, and safety of operation make data collection difficult. Data processing and interpretation require expert knowledge and are typically performed semi-manually and offline. To be economically viable in such mining environments, the hypercloud technology has to mature toward autonomy and real-time delivery of results. In recent years, terrestrial autonomous platforms have entered the market that are suited to the challenging conditions of underground mining and can maneuver and navigate even in confined, uneven, and poorly lit environments. They provide optimal carriers for hyperspectral sensors, which have simultaneously evolved into lighter, faster, and more robust devices. However, implementing hyperspectral sensors as payload for terrestrial autonomous robots remains challenging, especially in terms of  technical compatibility, ensuring data quality under complex conditions,  and processing large amounts of data quickly and autonomously. In our contribution, we demonstrate the potential of autonomous terrestrial robots combined with hyperspectral technology and advanced data processing for the automation of geological mapping. We present results of hyperspectral data acquisition using an autonomous robotic platform in a confined underground mining environment and discuss strategies for adapted sensor design, autonomous validation, real-time hypercloud processing, and enhanced autonomous navigation supported by hyperspectral information. 
Global thermal spring distribution and relationship to endogenous and exogenous factors
Authors: Tamburello Giancarlo , Chiodini Giovanni , Ciotoli Giancarlo , Procesi Monia , Rouwet Dmitri , Sandri Laura
Published: February 2023

In the last decades, the enormous potential for direct geothermal heat from aquifers attracted special attention, particularly toward those thermal springs indicating areas in which exploitation of geothermal energy might be economically feasible for indirect uses such as electrical power production. The availability of geochemical data besides the location of thermal spring areas assumes particular importance, especially in the first stages of a geothermal exploration program. In this work, we present a digitised format of the literature review of Gerald Ashley Waring on the geothermal springs of the world. This unprecedented dataset contains geographical coordinates (from georeferentiation) of ~6,000 geothermal spring areas, including complementary data such as temperatures, flow rates, total dissolved solids content (TDS, expressed in ppm), and quantitative chemical analysis of major elements (only for a few hundred sites). Using temperature and flow rate, we derive the heat discharged from 1483 thermal spring areas (between ~10-5 and ~103 MW, with a median value of ~0.5 MW and ~8300 MW in total). We complement this information with geological data sets currently available in the literature and analyse them using statistical and geospatial tools and a supervised machine-learning algorithm. We show that terrestrial heat flow, topography, volcanism, and extensional tectonic play a key role in the occurrence of thermal waters around the globe. These results can also be beneficial to address the geothermal interest towards specific and less studied areas and significantly drive the first steps of the geothermal surveys and detailed investigations. Finally, this data set in electronic format will be beneficial for future research on the spatial distribution of thermalism at a small scale and the variation of temperature and flow rate of several thermal springs in the last decades in certain regions.
New proxy estimates reveal low atmospheric CO2 levels before the emergence of forested ecosystems
Authors: Feulner Georg , Dahl Tais W. , Harding Magnus A.R. , Brugger Julia , Norrman Kion , Lomax Barry H. , Junium Christopher K.
Published: February 2023

Traditionally, the evolution of trees and the establishment of the first forests during the Devonian (419–359 Ma) have been linked to an enhancement of terrestrial weathering processes and a subsequent reduction of atmospheric carbon dioxide (CO2) levels by one order of magnitude. However, empirical estimates of early-Devonian CO2 concentrations are sparse and carry large error bars. Here we use leaf carbon isotopes, stomata density, and stomata pore length from fossilized lycophytes to estimate atmospheric CO2 levels 410–380Ma based on a mechanistic model for gas exchange calibrated using their closest modern lycophyte relatives. We find that Earth's atmosphere contained about 525–715 ppm of CO2 before the emergence of forested ecosystems, much less than previously thought. Using a coupled climate model, we show that Earth was partially glaciated at these moderate CO2 levels and that this cool climate state is in principle agreement with available climate proxies and fossil evidence for the distribution terrestrial vegetation. Finally, we use a process-based biogeochemical model to demonstrate that our results are consistent with a scenario in which enhanced weathering, climate cooling, and atmospheric oxygenation are associated with the earlier emergence of shallow-rooted vascular ecosystems rather than the appearance of the first forests.
Multi-scale numerical modelling of subduction interface rheology
Authors: Ioannidi Paraskevi Io , Schellart Wouter Pieter
Published: February 2023

The physical nature and the rheology of the subduction interface play an important role in the deformation of the overriding plate, the degree of locking of the subduction zone plate boundary, and the rate of subduction. Here, we employ the Finite Element Method (FEM) to determine the effect of matrix rheology on the bulk interface deformation. We use the open-source particle-in-cell FEM code Underworld (Moresi et al., 2007) to create synthetic 2D visco-plastic models of the subduction interface that deform by simple shear. The models comprise meter-scale blocks of continental affinity encompassed within a metasedimentary matrix. We investigate the effect of constant, Newtonian, and non-Newtonian matrix viscosities on the deformation and stress distribution in the models for large finite shear strains. We vary the percentage of block concentration from 10% to 65%, as well as the shear velocity while making sure the strain rates produced remain within the interseismic range, and we calculate strain localization and stresses within the models. Finally, we use the same viscosity formulations in large-scale 2D models of a subduction zone to investigate their influence on upper plate deformation and subduction rate during the interseismic stage. With this multi-scale analysis, we gain insight into how the same rheological law can affect deformation at different scales.
Energetic Particle Precipitation reflected in the Global Secondary Ozone Distribution
Authors: Jia Jia , Murberg Lisa E. , Løvset Tiril , Orsolini Yvan J. , Espy Patrick J. , Salinas Jude , Lee Jae N. , Wu Dong , Zhang Jiarong
Published: February 2023

The secondary ozone layer is a global peak in ozone abundance in the upper mesosphere-lower thermosphere (UMLT) around 90-95 km. The effect of energetic particle precipitation (EPP) from geomagnetic processes on this UMLT ozone has not been well studied. In this research we investigated how the secondary ozone response to EPP from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Aura and TIMED satellites, respectively. In addition, the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension and specified dynamics (SD-WACCM-X) was used to characterize the residual circulation during EPP events. By comparing ozone and circulation changes under High- and low-Ap conditions, we report regions of secondary ozone enhancement or deficit across low, mid and high latitudes as a result of circulation and transport changes induced by EPP.