bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced sensitivity of atmospheric CO2 growth rate variations to tropical mean temperature anomalies is driven by internal climate variability in a large climate model ensemble
Authors: Li Na , Sippel Sebastian , Linscheid Nora , Rödenbeck Christian , Winkler Alexander , Reichstein Markus , Mahecha Miguel , Bastos Ana
Published: February 2023

The atmospheric CO2 growth rate (AGR) shows large year-to-year variations, which are mainly driven by land and ocean carbon uptake variations. Recent studies suggested an approximate doubling of the AGR regressed onto tropical mean temperature anomalies (“sensitivity of AGR to tropical mean temperature anomalies”; Wang et al., 2014; Luo et al., 2022), which was attributed to increasing drought in tropical land vegetation areas in a warming climate (Wang et al., 2014). We hypothesise that at least part of this apparent sensitivity change may instead be explained by extratropical areas and by internal climate variability.Here, we study the apparent sensitivity changes of AGR to tropical mean temperature in observations, atmospheric inversions, and a large climate model ensemble of historical simulations. First, we identify the main regional drivers of the apparent sensitivity change, including the ocean and extratropical regions in all datasets. Then, we evaluate whether these sensitivity changes can be attributed to anthropogenic forcing in a large climate model ensemble, or whether they are mostly driven by internal climate variability. Our results show that other regions beyond the land tropics contribute to the change in apparent sensitivity of AGR to tropical mean temperature anomalies in atmospheric inversions and in the period 1960 to 2006. Furthermore, the climate model large ensemble shows that such "doubling sensitivity" events can occur due to internal climate variability only. This points to the importance of distinguishing internal climate variability from forced signals when attributing causes to observed changes in the carbon cycle.Wang, X., Piao, S., Ciais, P. et al. A two-fold increase of carbon cycle sensitivity to tropical temperature variations. Nature 506, 212–215 (2014). https://doi.org/10.1038/nature12915Luo, X., Keenan, T. F. Tropical extreme droughts drive long-term increase in atmospheric CO2 growth rate variability. Nat Commun 13, 1193 (2022). https://doi.org/10.1038/s41467-022-28824-5
High-density 3D and 4D GPR data acquisitions over alpine glaciers using a newly developed drone-based system.
Authors: Ruols Bastien , Baron Ludovic , Irving James
Published: February 2023

We have developed a drone-based GPR system at the University of Lausanne that allows for the safe and efficient acquisition of large, high-density, 3D and 4D datasets over alpine glaciers. The system is able to record approximately 4 line-km of high-quality GPR data per set of drone batteries in less than 30 minutes of operation which, combined with multiple sets of batteries and/or the possibility of charging at the field site, means that 3D datasets over a large area can be acquired with unprecedented efficiency. The latter performance is possible thanks to (i) a custom-made real-time-sampling GPR controller that has been specifically designed for glaciers studies, (ii) minimization of the total payload weight using custom-built antennas and carbon-fiber components, and (iii) development of an optimized survey methodology. Further, because the drone is equipped with real-time kinematic GPS positioning, survey paths can be repeated with great precision, which opens new opportunities in term of 4D data acquisitions.In the summer of 2022, we acquired both 3D and 4D data over two Swiss glaciers. On the Otemma glacier, we surveyed a grid of 462 profiles representing a total length of 112 line-km of data in only four days. After 3D binning, the trace spacing intervals in the in-line and crossline directions were respectively 0.4 m and 1 m, making this arguably the largest 3D GPR dataset of such density ever recorded over ice. The interface between the ice and the bedrock, visible on all profiles, extends to 1000 ns which translates into a depth of approximately 80 m. In addition, internal englacial and subglacial 3D structures are clearly detectable.In parallel, we visited the Rhône glacier on a monthly basis between June and September 2022. A collapse feature, identified by the presence of large circular crevasses, had formed and was evolving close to the snout of the glacier. This represented a great opportunity to test the 4D acquisition capabilities of our system. We collected four high-density 3D datasets on the same survey grid. The repeatability of the trajectories was excellent as the paths differ only by a few centimeters between occurrences. Clear variations in the internal structure of the glacier are visible which will be investigated in the upcoming months.
Basal Conditions and Sedimentary Structure of the Whillans Ice Stream.
Authors: Winberry J. Paul
Published: February 2023

The Whillans Ice Stream (WIS) is a major outlet of the West Antarctic Ice Sheet. Significantly, the downstream portion of the WIS is presently decelerating, possibly stagnating by the end of this century. Additionally, this downstream region of WIS is unique in that it moves primarily by stick-slip motion. However, both the rate of deceleration as well as the percent of motion accommodated by stick-slip motion is spatially variable. Such spatial variability is potentially linked to associated variability in basal conditions. Active source seismic measurement are capable of providing high-resolution insights into basal conditions, however, they are time-consuming to collect, limiting the spatial extent over which they can be acquired. In this presentation, we will use passive seismic measurements collected at over 50 seismic stations to map sediment thickness and ice-bed conditions across the region. This will be done using the receiver function method which images the depth and physical properties of sediments by modeling the arrival times and amplitudes of seismic waves that interact with subglacial sedimentary structures. We will first map conditions at the ice-bed interface by using relatively high-frequency waveforms (> 2 Hz) as they are sensitive to the physical properties of the shallow (< 20m ) subglacial sediments layers. Across the entirety of the study region, we find that this uppermost layer of sediments is characterized by relatively high porosity sediments.  Second, we will utilize lower frequencies (< 2 Hz) to map the depth basement, finding that the entire region is underlain 100’s of meters of sediments (Gustafson et al., Science, 2022). We will use our maps of sediment properties and thickness to investigate potential mechanisms for the observed variability in deceleration and stick-slip behavior of the WIS.  
Risk-based Decision Support System for Early Warning of Chemical Emissions in Flood Event: A Case Study of Crystallization Factories in Liberec City, Czech Republic
Authors: Gheibi Mohamad , Khaleghiabbasabadi Masoud , Socha Barbara , Wacławek Stanisław , Černík Miroslav
Published: February 2023

Based on the reports presented in various studies, it appears that in the Czech Republic, in 2002, as a result of a fluvial flood, chlorine and other chemicals in a factory were washed away and led to various epidemiological effects [1]. This paper presents a Decision Support System (DSS) based on Random Forest (RF) artificial intelligence technique and Failure Modes and Effects Analysis (FMEA) [2] to minimize the chemical risks in industrial factories and control possible pollution from crystallization plants. The methodology is demonstrated by its application on real crystallization plant in Liberec, Czech Republic. The investigations demonstrated that the RF algorithm has the ability to predict the severity of the occurrence and the Risk Probability Number (RPN) of spreading pollution with more than 90% regression coefficient. On the other hand, combining the machine learning method with the risk analysis has the possibility of heavy metal emission risk detection as well as the presentation of available solutions using the classic Delphi technique [3,4]. The evaluations of this research proved that the proposed methdology can significantly increase the biological security of citizens in crisis conditions.Keywords: Flood; Decision Support System; Machine Learning; Risk Analysis; Czech Republic.  Reference[1] Gautam, K.P. and Van Der Hoek, E.E., 2003. Literature study on environmental impact of floods. DC1-233-13.[2] Gheibi, M., Karrabi, M. and Eftekhari, M., 2019. Designing a smart risk analysis method for gas chlorination units of water treatment plants with combination of Failure Mode Effects Analysis, Shannon Entropy, and Petri Net Modeling. Ecotoxicology and Environmental Safety, 171, pp.600-608.[3] Zabihi, O., Siamaki, M., Gheibi, M., Akrami, M. and Hajiaghaei-Keshteli, M., 2023. A smart sustainable system for flood damage management with the application of artificial intelligence and multi-criteria decision-making computations. International Journal of Disaster Risk Reduction, 84, p.103470.[4] Akbarian, H., Gheibi, M., Hajiaghaei-Keshteli, M. and Rahmani, M., 2022. A hybrid novel framework for flood disaster risk control in developing countries based on smart prediction systems and prioritized scenarios. Journal of environmental management, 312, p.114939.
Can AI-generated landslide inventories replace humans' cognitive abilities in hazard and risk scenarios?
Authors: Meena Sansar Raj , Floris Mario , Catani Filippo
Published: February 2023

Landslide inventories are quintessential for landslide susceptibility mapping, hazard modeling, and risk management. Experts and organizations all across the world have preferred manual visual interpretation of satellite and aerial imagery for decades. However, there are other issues with manual inventory, such as the subjective process of manually extracting landslide boundaries, the lack of sharing landslide polygons within the geoscientific community, and the amount of time and effort engaged in the inventory generation process by the expert interpreters. To address these challenges, a large amount of research on semi-automated and automatic mapping of landslide inventories has been conducted in recent years. The automatic development of landslide inventory using Artificial Intelligence (AI) approaches is still in its early stages, as there is currently no published study that can generate a ground truth representation of a landslide situation following a landslide-triggering event. In terms of landslide boundary delineation utilizing AI-based models, the evaluation metrics in recent research suggest a range of 50-80% of the F1-score. However, with the exception of those using model evaluation testing in the same studied area, very few studies claim to have attained more than 80% F1 score, that too at larger scales of investigation. As a result, there is currently a research gap between the generation of AI-based landslide inventory and their applicability for landslide hazard and risk assessments. There is a need to advocate for the geoscientific community to check the reliability of AI-generated landslide data in terms of their usage in the succeeding phases of landslide response and mitigation in impacted areas.
DeepMIP-Eocene: A window to a super-warm world, 50 million years ago, through an model-model-proxy-proxy intercomparison approach
Authors: Lunt Dan ,   The DeepMIP Team
Published: February 2023

DeepMIP-Eocene is a community project dedicated to improving our understanding of the super-warm Eocene climate, ~50 million years ago. The objectives of the DeepMIP group include fostering closer links between the palaeoclimate modelling and data communities; designing and carrying out paleoclimate model simulations; creating and synthesising datasets to enable meaningful model-data comparisons; and analysing the results with the aims of evaluating the models, understanding the reasons behind the model-model and model-data differences, and, where possible, providing suggestions for model improvements.DeepMIP-Eocene is nearing completion of its first phase.  In this talk, I will present the key results to emerge from this first phase.  This includes the large-scale modelled features of the Eocene climate (including the causes of polar amplification), model-data comparisons (including an assessment of whether models have improved over time), climate and Earth system sensitivity (derived from both proxies and models), ocean circulation (including an assessment of likely regions of deep water formation),  sea ice and Arctic climate,  and African and Australian hydroclimate.I will finish with an outlook to the next phase of DeepMIP-Eocene, including new aspects of the experimental design and novel analyses.
Combining OPERA Dynamic Surface Water Extent (DSWx) with in situ measurements to improve product development and application
Authors: Jones John , Bansal Sheel , Meier Jacob , Pearl Christopher
Published: February 2023

NASA created the Observational Products for End-Users from Remote Sensing Analysis (OPERA) project to develop satellite-based analysis ready data products for resource management, environmental protection, and science. The OPERA product that is focused on inland surface water detection, Dynamic Surface Water Extent (DSWx), will be produced using data from both optical and synthetic aperture RADAR systems. The first DSWx product release (DSWx-HLS) relies on Harmonized Landsat Sentinel-2 (HLS) data to yield a median observation frequency of 3 days at the equator with near-global coverage. Subsequent DSWx releases will be based on inputs from Sentinel-1, Surface Water Ocean Topography (SWOT), and NASA-ISRO Synthetic Aperture Radar (NISAR).DSWx accuracy in monitoring open water bodies is estimated through comparison with coincident, higher spatial resolution satellite imagery for locations around the globe. DSWx product suite algorithms also target the detection of mixtures of water and vegetation at input data subpixel scale as well as water under vegetation. The accurate assessment of algorithm performance given these especially challenging targets requires the development and analysis of databases that have as a foundation, data collected in the field.A DSWx predecessor (USGS DSWE) and provisional DSWx data have been combined with in situ data on river discharge, aquatic species occurrence, water quality, and wetland processes to test and develop product utility. At sites spread across the US, low-cost sensors have been employed to record surface inundation. Trail cameras adapted for scientific research are providing useful information on weather, vegetation, and water conditions. Imagery from multiple high-resolution remote sensing instruments, including uncrewed aerial systems and commercial satellites, as well as sensors on-board the International Space Station, are being periodically collected. During intensive field campaigns, vegetation structure is being measured at each site. The imagery and in situ data are combined to improve DSWx development, uncertainty assessment, and application.
Mud volcanism and creeping mud flows
Authors: Mazzini Adriano , Jodry Clara , Broz Petr , Akhmanov Grigorii , Blahůt Jan , Lupi Matteo , Karimova Nigar , Braize Damian , Nobile Adriano , Khasayeva-Huseynova Ayten , Guliyev Ibrahim
Published: February 2023

Mud volcanism is a natural phenomenon manifesting at the surface of the body with spectacular eruptions and a large variety of morphologies resulting both from explosive and effusive activity. In this study, we targeted two large (MVs) in Azerbaijan (Lokbatan and Goturdagh) characterized by different behaviors in eruptive activity. We investigated them using a multidisciplinary approach including field observation combined with drone photogrammetry, InSAR imaging, subsurface multisource survey, geotechnical analyses of mud breccia flows and numerical stability modeling in order to reveal the way the mud flows.Lokbatan most recently erupted in August 2022. Field observations in September 2022, before significant modification by rain, reveal that this most recent eruption, albeit small in terms of extruded mud breccia, triggered the disruption of huge segmented portions of the older mud flows that extend for more than 1 km. This was identified by the formation of series of fractures recording the detachment and subsequent downhill movement of the old flow. No evident ground deformations have been observed before the eruption and, repetitive field campaigns in subsequent months do not reveal any network of fresh fractures and dislocations. On the other hand, Goturdagh MV features a constant slow extrusion of compacted mud breccia from the subsurface forming an extended >1.2 km long mud flow that continuously moves. This movement is clearly visible at the top of the MV where repetitive field observations reveal an extrusion of wet and dark colored mud breccia. Along the slope, the movement creates well-developed shear zones and compressional structures typical of slope deformations. At the bottom however, the movement seem to be discontinuous and might be triggered occasionally when the force of the new material becomes critical.The field observations show that kilometer scale mass transport can extend at MVs for more than 1 km along the flank of these structures. The additional approaches will help us identify possible eruptive precursors and understand if external elements (tectonics, rainfall, …) can influence this mass movement. The same phenomenon is likely happening at many other large-scale features worldwide.
Seasonal solar radiation input of building surfaces depending on latitude, orientation and urban design- implications for urban greening
Authors: Dahm Yannick , Nehls Thomas
Published: February 2023

Photovoltaic electricity, heat, or biomass are potential products of transformed solar radiation on building envelopes. In the urban landscape all of these energy forms can be used. Walls can be heated when left blank (in winter) and plants can generate biomass, which stores CO2. Roof- and facade greening are both discussed climate change mitigation and adaptation strategies, whereas its cooling performance is of highest interest in order to prevent indoor heat stress in urban areas, e.g. in the mid latitudes. Shading is the most effective cooling process before transpiration and insulation, its impact depends on the solar radiation. Therefore, solar radiation must be quantified for a set of typical urban conditions in order to prioritize roof or façade greening as the most effective cooling strategy.The latitude and the regional climatic conditions have an impact on the radiation absorbed by the roofs and the facades of a city. Additionally, the urban design (street canyon height-to-width ratio, roof-to-facade area ratio, altitude of the facade and roof, albedo) and the building orientation play an important role.We simulated idealized (clear sky conditions, constant albedo and elevation) and realistic scenarios (accounting realistic mean annual weather conditions) with three simplified urban designs (street canyon height-to-width ratio =1, 0.5, 0), using the meteonorm database for seven latitudinal evenly distributed cities between the equator and Svalbard. We present results for buildings with a roof to facade ratio of 1, 2 and 3 and discuss the corresponding effectiveness of roof and facade greening.
Existence and Distribution of Basin-Wide Strike Slip Fault Systems in an Asymmetrical Back Arc Rift System: The Black Sea Basin
Authors: Kaykun Armagan , Pysklywec Russell
Published: February 2023

The Black Sea Basin has been a focus of interest due to its economically promising hydrocarbon reserves and complex tectonic history. Several different theories were proposed to decipher its enigmatic basin formation and tectonic evolution processes.One important characteristic of the Black Sea Basin that makes it unique is its isolation from the world oceans, and global sea level changes for long periods during the geological time. This provides a good realm to correlate tectonic episodes with rapid sedimentation patterns in its thick sedimentary section. With the aim of modelling this sequence of events, we reviewed and reinterpreted previously proposed scenarios. We focus on the back-arc rifting and subsequent tectonic inversion that led the surrounding mountain belts to form. By reinterpreting 24 long-offset 2D seismic lines acquired by GWL in 2011, we propose a new structural framework for the Black Sea Basin.Our structural geology analyses show that in addition to basin-bounding normal faults and inversion tectonics, numerous flower structures occur in both the western and eastern Black Sea subbasins. These flower structures are typical indicators of strike-slip fault systems and in the Black sea Basin case, the orientation of these fault systems is roughly east-west. Our interpretations align with the hinge model that Stephenson and Schellart (Geological Society London Special Publications, 2010) proposed to explain the opening of the Black Sea Basin as one basin rather than the conventional interpretation of a two separate rifted basin configuration. The proposed tectonic framework sheds light on the geometry of the Black Sea Basin’s bounding faults, complex faulting and folding recognized in the sedimentary section, and complex ridge-depression geometry.
Mountain glaciers during the Late Glacial and Holocene in Arctic Norway 
Authors: Bakke Jostein , Paasche Øyvind , Schaefer Joerg
Published: February 2023

The accelerated melting of ice in the polar regions suggests that the cryosphere is edging towards an irreversible tipping point. How unusual is this trend of ice loss within the frame of natural variability, and to what extent can it be explained by underlying climate dynamics? The SHIFTS project aimed to provide a new avenue for understanding how bi-polar climate varied during the Late Glacial and the Holocene by reconstructing primary features of atmospheric circulation and variability by using glaciers as climate indicators for both northern and southern hemisphere. In north, on the west coast of Troms and Finnmark we have mapped and sampled glacier forelands for cosmogenic dating. These results are combined with an extensive lake coring program targeting lakes with and without glacial input in Arctic Norway. At the Island of Arnøy, western Finnmark we mapped a glacier foreland to build a cosmogenic nuclide chronology from 71 moraine boulders deposited during the late glacial and the Holocene. Our record suggest that this Arctic Norway record reached its maximum late glacial extent about 14 ka ago, prior to the Younger Dryas. Following considerable retreat through the first part of the YD, glaciers re-stabilized in the mid-YD and showed slower oscillatory retreat through the latter part of the YD. This retreat pattern is confirmed from a lake sediment study at Andøya further south in Northern Norway. The sub-annually reconstruction show a glacier advance during the Intra Allerød cold period and thereafter a gradually retreat towards the end of the Younger Dryas when the glacier again did a re-advance. The results from the reconstructed Arctic glaciers during the late glacial show consistency to the glacier record from the southern hemisphere e.g., at South Georgia, New Zealand and in Patagonia. For the Holocene reconstruction we have used analyses of sediments deposited in distal glacier-fed lakes. We recorded several short-lived glacier advances in the early Holocene followed by a genera glacier retreat between 9000 and 7000 cal. yr BP, interrupted by a glacier advance 8200 years ago. Most glaciers were melted away between 7000 and 5200 cal. years BP. After this the glaciers advanced throughout the “Neoglacial”, until they reached its maximum extent during the “Little Ice Age”. The two “Little Ice Age” moraines in the upper valley of Rødhetta at the Island of Arnøy is dated to 480 and 390 yrs. BP using cosmogenic dating. This overall trend is coherent compared to other glacier reconstructions from Arctic Norway, however variations on multi-decadal time scales are observed that possibly reflect more local climatic changes and/or uncertainties associated with the methods employed in this study.
Using Legacy Data to Explore the Onset and Development of the Southern Hemisphere Supergyre
Authors: Christensen Beth , Drury Anna Joy , Auer Gerald , DeVleeschouwer David , Lyu Jing
Published: February 2023

The Southern Hemisphere Supergyre refers to the strong connections and intertwining of the southern subtropical gyres. Tasman Leakage is a fundamental part of the supergyre, as well as of the  global thermohaline circulation, as it provides a return flow from the Pacific and Indian Oceans to the North Atlantic at intermediate depths.   However, both are only relatively recently documented, and the timing and conditions of onset are not well understood.This study characterizes the newly identified onset of Tasman Leakage in sedimentary records in and around the Indian Ocean using core descriptions and data derived from sediments.  Since much of this is legacy core material, core photographs were used to develop complementary and more continuous records to help refine the timing of onset.  These newly constructed time series based on core photographs are compared with X-ray Fluorescence time series based on core scanning provide both insight into onset of Tasman Leakage and a first test of the utility of time series based on core photos.This effort will focus on the intermediate water pathway associated with Tasman Leakage and identify conditions at critical around the basin from at least 8 Ma at Broken Ridge and Mascarene Plateau to understand the role of Indian Ocean intermediate waters in the Southern Hemisphere Supergyre in major climate events of the late Miocene. This proposed work provides the first synoptic view of SHS onset using intermediate depth cores, which in turn will provide an important framework for basin-wide synthesis of Indian Ocean drilling, much of which is outside of the main pathway of the SHS.  It will also serve as a test of the utility of legacy material as primary data.
Spatial and temporal variability of water masses in the Southern Ross Sea
Authors: Heywood Karen J. , Portela Esther , Smith Walker , Damerell Gillian , Sheehan Peter , Meyer Meredith
Published: February 2023

Relatively warm modified Circumpolar Deep Water accesses the southern Ross Sea steered by bathymetric troughs. There it provides nutrients to support phytoplankton blooms in spring, and heat to melt the Ross Ice Shelf.  Here we present new observations collected by two ocean gliders during December 2022 and January 2023, in the Ross Sea polynya adjacent to the Ross Ice Shelf.  The gliders surveyed the full depth of the water column (about 700 m depth) carrying sensors measuring temperature, salinity, dissolved oxygen, chlorophyll fluorescence and optical backscatter, and also yielded estimates of the dive-average-current which we use to reference geostrophic shear.  Repeated quasi-meridional high resolution (profiles approximately every 1.5 km) sections along the sea ice edge allow analysis of the spatial and temporal variability, as well capturing the dynamic field of eddies, tides and coastal current. We discuss the influence of the sea ice and the atmospheric forcing on the water properties. One glider made an unauthorised foray beneath the Ross Ice Shelf, surveying the upper 200 m of the water column in high resolution beneath an ice shelf base at about 80 m depth. We observe solar-warmed water penetrating beneath the ice shelf with significant signatures of elevated chlorophyll fluorescence and optical backscatter, and low oxygen and salinity. We discuss the likely mechanisms involved in advecting this water beneath the ice shelf and its importance for physical and biogeochemical processes of ocean-ice interaction.
Emissions from Mining-related Activities in Africa using TROPOMI Satellite Observations
Authors: Martínez-Alonso Sara , Veefkind Pepijn , Dix Barbara , Gaubert Benjamin , Granier Claire , Soulié Antonin , Darras Sabine , Theys Nicolas , Emmons Louisa , Eskes Henk , Tang Wenfu , Worden Helen , deGouw Joost , Levelt Pieternel
Published: February 2023

We have analyzed TROPOMI NO2 data over the Copperbelt, a mining region which straddles the Democratic Republic of Congo and Zambia. While the ore mined there is primarily copper, this region is currently of great strategic interest because it is the world’s biggest producer of cobalt. Demand for cobalt, key to clean energy technologies (e.g., electric car batteries), is increasing worldwide and cobalt control is becoming a matter of national and global energy security. The impact of increasing mining-related activities on local air quality (high NOx is harmful to respiratory systems and crops) is unknown.TROPOMI, onboard ESA’s Sentinel-5 Precursor, is an imaging spectrometer in a sun-synchronous orbit at 824 km of altitude which measures concentrations of relevant atmospheric species (trace gases, aerosols, cloud) with quasi-global daily coverage and at high spatial resolution (~ 3.5 x 5.5 km2 in the case of NO2).We show that mining-related activities (such as extraction, smelting, and refining) can be remotely detected based on their TROPOMI NO2 signature, even in the presence of high background NO2 from biomass burning. Annual TROPOMI NO2 means for 2019, 2020, and 2021 show local enrichments consistent with point sources spatially collocated with both mines and large cities where mining-related activities take place. We have identified temporal trends in NO2 from these point sources and, when possible, we have compared those to production figures from the mining companies involved. We have quantified top-down annual NOx (NO+NO2) emissions for each of the point sources identified by applying the divergence method to the TROPOMI retrievals, using ancillary ERA5 meteorological data. Because in situ NOx measurements are not available, we contrast our emission results with emissions from the CAMS-GLOB-ANT v5.1 inventory.Our results show that NOx emissions from mining-related activities can be quantified remotely, which is important in the absence of local air quality monitoring. They also demonstrate that NO2 trend analysis can be a good indicator of mine production. This is particularly relevant for non-publicly traded mining companies, which are not required to publish their production figures. Lack of TROPOMI SO2 enhancements colocated with our NO2 point sources is consistent with SO2 capture and transformation into H2SO4, which is then used in mining-related processes or commercialized.
Interrogating the influence of shallow convective mixing on low-level clouds with observations of stable water isotopes
Authors: Dee Sylvia , Hu Jun , Bailey Adriana , Nusbaumer Jesse , Sasser Christiana , Worden John
Published: February 2023

Low-cloud feedbacks contribute large uncertainties to climate projections and estimated climate sensitivity. A key physical process modulating low-cloud feedbacks is shallow convective mixing between the boundary layer and the free troposphere. However, there are challenges in acquiring observational estimations of shallow convective mixing with global coverage. To this end, we propose a novel approach to constraining convective mixing using stable water vapor isotope profiles from satellite retrievals. We demonstrate that the vertical gradient of water vapor δD between the boundary layer and free troposphere can be used to track shallow convective mixing, especially over the trade-wind regions. We also evaluate this metric of shallow convective mixing against the EUREC4A experiment data. Analyzing isotopes in water vapor alongside low-cloud properties from satellite retrievals, we find that low-cloud fraction appears insensitive to convective mixing in trade cumulus regions. Our results suggest that satellite-derived observations of the relationship between shallow convective mixing and low-cloud are regionally-dependent, and strong shallow convective mixing is associated with moistening of the free troposphere in the tropics. The new estimations of low-cloud properties and their relationship with changes in convective mixing using water isotopes house potential to improve the simulation of low-cloud feedbacks in numerical simulations, refining estimates of climate sensitivity.
Nutrient pollution impact reduction assessment in a deep estuary, euphotic zone avoidance/bypass considerations
Authors: Khangaonkar Tarang , Yun Su Kyong , Premathilake Lakshitha
Published: February 2023

The feasibility of reducing nutrient pollution impacts by redirecting excess nutrient flux away from the photic zone is investigated. Alternate effluent discharge strategies to avoid or bypass the euphotic zone were tested under the hypothesis that in deep estuaries, depth of the surface exchange outflow layer may be greater than euphotic zone depth, providing opportunity for a fraction of the nutrient pollution to be exported out passively. We used the Salish Sea region in the Pacific Northwest as a test bed for this assessment. Euphotic zone depth in the Puget Sound basin of Salish Sea in U.S waters varies from 8 m to 25 m while the depth of outflow layer is approximately 60m. Sensitivity of biological response and water quality impact were quantified using an established biophysical model of the system, using exposure to low DO levels as the metric (< 2 mg/L hypoxia and < 5 mg/L impairment). Opportunity to reduce nutrient pollution impact was tested through outfall relocation strategies, applied to 99% of the anthropogenic loads currently delivered to the Puget Sound. The results show that relative to natural impairment levels, marine wastewater outfalls are responsible for 36% of increase, while loads from upstream watersheds that enter Puget Sound via river flows, are responsible for 70% of increase in impairment. Results were consistent with the hypothesis in that moving the outfalls to deeper waters resulted in reduced primary production. However, in some basins, the benefits of lower water column respiration were offset by reduced DO production and were accompanied by some loss in the strength of circulation. Puget Sound basin results indicate worsening of DO impairment hours (average +3.0%), while Whidbey Basin showed improvement in DO impairment hours (-6.8%) relative to existing conditions. The results indicate that presence of multiple sills and the associated reflux flows / circulation obstruct the export of nutrients out of the system. The efforts to relocate outfalls to achieve euphotic zone bypass and improve DO impairment were therefore not as effective as hypothesized.
Assessment of centralized and decentralized water reclamation with resource recovery in Leh, India by taking a Nexus approach and applying a MCDA framework
Authors: Gondhalekar Daphne , Bhaduri Anik , Waibel David , Qureshi Areeba
Published: February 2023

Worldwide, urbanization and economic growth are driving up consumption of natural resources such as water, energy and food exponentially particularly in cities, with very serious environmental and climate change implications. These issues are exacerbated by the fact that cities keep implementing resource intensive infrastructures even in water-stressed regions although many cities are already grappling to supply basic services. To counter climate change, cities need to take a more circular Nexus approach to infrastructure development. Leh in the Indian Himalaya in the semi-arid high-altitude region of Ladakh, is a typical rapidly transforming small city facing serious issues of water scarcity and wastewater management due to very rapid economic growth. These are linked to questions of energy and food security and need to be addressed urgently in Leh. To protect drinking water quality the local government is implementing a centralized sewerage system in Leh. However, this is now not working as expected due to various reasons and some parts of Leh need a separate decentralized solution. This project takes a multi-criteria decision analysis framework and uses an expert interview survey to determine in which parts of Leh decentralized water reclamation with resource recovery is socio-economically viable. This research is expected to have implications for rapidly transforming cities worldwide seeking net zero carbon development.
Intra- and inter-annual melt water patterns on George VI Ice Shelf, Antarctic Peninsula, from synthetic aperture radar and optical satellite imagery
Authors: Willis Ian , Deakin Katherine , Dell Becky , Dirscherl Mariel
Published: February 2023

Meltwater retention on the surface of ice shelves may lead to hydrofracturing and ultimately their breakup and collapse. Several methods have been used to map surface meltwater on ice shelves from satellite imagery, but a comparison of the methods and a systematic analysis of the results has not been undertaken. Here we bring together two recent inventories of surface meltwater features that use machine learning technologies to map: i) ponds from both Sentinel-2 optical and Sentinel-1 SAR imagery; and ii) both ponds and slush from Landsat 8 optical imagery. We analyse the meltwater products at a bi-monthly (twice a month) timescale over six austral summers between November 2015 and March 2021 for the George VI Ice Shelf, Antarctic Peninsula. We investigate the data sets to reveal the seasonal evolution of surface and shallow subsurface meltwater in terms of the onset, cessation and therefore duration of slush and ponded water, as well as the persistency of slush and ponded water areas from year to year. We find areas where the evolution follows similar patterns from year to year, but also highly anomalous patterns and timings in other years. Finally, a systematic analysis of Sentinel 1 imagery throughout the winter seasons reveals several perennial shallow surface water bodies.
The first Gravity Geoid Model for Israel
Authors: Sarid Hezi , Dalyot Sagy , Wang Yan-Ming
Published: February 2023

This research introduces the formation of a Geoid model that is based on terrestrial gravity measurements in Israel and its surroundings, together with shipborne gravity measurements and altimetry data over the Mediterranean Sea, using the EIGEN-6C4 as the reference earth gravity model – the first of a kind effort done in Israel to construct such a model. A challenging aspect for establishing this model for this area - that does not exist elsewhere in the world - is that approximately 20% of Israel's land area is located below sea level, some of which is minus 430 meters, mainly along the Dead Sea Rift. This unique topography requires new and challenging computation theories for gravimetric Geoid determination.The results yield a standard deviation value of the gravimetric Geoid of 5.7 cm. The model is also successfully calculated in areas with a negative orthometric altitude, which proves for the first time the potential of the developed methodology of obtaining an accurate geoid model. The hybrid Geoid model significantly improves these values, where the standard deviation value is reduced to 2 cm with an error range of 22 cm. The hybrid Geoid model retains the orthometric datum of the control points while relying on gravimetric data to provide better gradient information about the area. The high accuracy of the hybrid Geoid model will allow the integration of the official national Geoid model and the new gravimetric Geoid model to support precise GNSS measurements used for precise infrastructure engineering projects. The gravimetric geoid can recreate a role with other local gravity models developed by countries surrounding Israel.
Relative contribution of eddies ant atmospheric forcing to the Bay of Bengal non-seasonal Sea Surface Salinity Variability
Authors: Montero Marie , de Boyer Montégut Clément , Vialard Jérôme , Llovel William , Penduff Thierry , Molines Jean-Marc , Leroux Stephanie , Reul Nicolas , Tournadre Jean
Published: February 2023

The Bay of Bengal (BoB) Sea Surface Salinity (SSS) is highly contrasted and variable, in response to the large monsoonal wind and freshwater forcing. In addition to this strong seasonal cycle, previous studies have underlined strong SSS non-seasonal variations associated with the Indian Ocean Dipole (IOD) and mesoscale eddies. In this study, we quantify the relative contributions of externally forced (wind, freshwater) and internally generated (mesoscale eddies) SSS non-seasonal variability in the BoB. To that end, we use Ocean General Circulation Model 10-member ensemble experiments from the IMHOTEP (IMpacts of freshwater discHarge interannual variability on Ocean heaT-salt contents and rEgional sea-level change over the altimetry Period) project.The model reproduces the large forced interannual SSS signals in the Northernmost part of the BoB and along the east coast of India, associated with the East Indian Coastal Current (EICC) modulation by the IOD. The internal SSS variability is largest in boreal fall in the North-Western BoB and more tightly controlled by the climatological SSS gradient distribution than by that of eddy kinetic energy. The external atmospheric forcing dominates the total variability in the regions of strongest variability, near the Ganges mouth and along the east coast of India in boreal fall and winter. Internal variability, however, contributes to 50-70% of the variability further offshore in boreal fall and winter. This confirms the strong role of eddies in controlling the freshwater extension up to ~700 km away from the coast, through stirring of the intense gradient between the coastal fresh and offshore saltier water. We finally discuss the consequences of these findings for comparing model and observations, in view of the chaotic nature of internal eddy variability.
Improved uncertainty estimates for the exponential filter method in a long-term error characterised root-zone soil moisture dataset.
Authors: Pasik Adam , Gruber Alexander , Preimesberger Wolfgang , De Santis Domenico , Dorigo Wouter
Published: February 2023

Root zone soil moisture, as the water available for plant uptake, effects evapotranspiration and has an important role in predicting droughts and agricultural yields. While microwave remote sensing retrievals are limited to observing the topmost few centimetres of the soil, they can be used with a variety of methods to infer the water content in the root zone due to the existing link between the dynamics in both layers. Regardless of their methodologies, most root zone soil moisture datasets do not provide uncertainty estimates.Among the techniques for approximating root zone soil moisture, the exponential filter method stands out as a relatively non-complex approach essentially smoothing and delaying surface observations which are generally characterized by greater temporal dynamics. The uncertainties of the exponential filter method are poorly analysed and typically unavailable. To address this gap, we extend the standard law for the propagation of uncertainties to characterize the random error variances of the exponential filter-based root zone soil moisture estimates. The proposed method considers the uncertainties of the input surface soil moisture retrievals and their availability in time as well as those of the exponential filter’s parameter and the method’s model structural error. The latter two components of the uncertainty budget are temporally-static values estimated from ground reference measurements at various depths. The resulting time-variant uncertainty estimates are realistic both in magnitude and temporal variations. 
Global biogeography of the biodiversity-productivity relationship in forests
Authors: Ma Haozhi , Zohner Constantin , Maynard Daniel , Delavaux Camille , Berdugo Miguel , Bialic-Murphy Lalasia , Mo Lidong , Mirzagholi Leila , Crowther Thomas
Published: February 2023

The biodiversity-productivity relationship (BPR) is central to our understanding of ecosystem functioning and restoration practices. Quantifying variation in the BPR across environmental gradients is thus critical for a spatially-explicit understanding of this key ecosystem property. Here, by integrating plot-level tree occurrence information from the Global Forest Biodiversity initiative (GFBi), satellite-derived net primary productivity, and environmental covariates, we estimated global variation in the BPR of forests along spatial and environmental gradients. The results show that variation in the forest BPR correlates with temperature and water availability, leading to significant differences in the forest BPR across biomes: the highest positive BPR occurs in arid and boreal forests, the lowest BPR in temperate broadleaved and mixed forests. In addition, forest age played a key role in mediating the BPR, with no BPR found in young forests (<100 years) and an increasingly positive BPR found in older forests. By quantifying the main drivers of global variation in the forest BPR, our study aids to a better understanding of forest ecosystem functioning and carbon storage and the global consequences of biodiversity loss.
Applicability of remote sensing evapotranspiration products in reducing uncertainty and equifinality in hydrological model calibration of Oued El Abid watershed.
Authors: Taia Soufiane , Erraioui Lamia , Chao Jamal , El Mansouri Bouabid , Scozzari Andrea
Published: February 2023

Typically, hydrological models are calibrated using observed streamflow at the outlet of the watershed. This approach may fail to mimic landscape characteristics, which significantly impact runoff generation because the streamflow incorporates contributions from several hydrological components. However, remotely sensed evapotranspiration (AET) products are commonly used as additional data with streamflow to better constrain model parameters. Several researchers demonstrated the efficacy of AET products in reducing the degree of equifinality and predictive uncertainty, resulting in a significant enhancement in hydrological modelling. Due to the variety of publicly available AET datasets, which vary in their methods, parameterization, and spatiotemporal resolution, selecting an appropriate AET for hydrological modelling is of great importance. The purpose of this study is to investigate the difference in simulated hydrologic responses resulting from the inclusion of different remotely sensed AET products in a single and multi-objective calibration with observed streamflow data. The GLEAM_3.6a, GLEAM_3.6b, MOD16A2, GLDAS, PML_V2, TerraClimate, FLDAS, and SSEBop datasets were downloaded and incorporated into the calibration of the SWAT hydrological model. The findings indicate that the incorporation of remotely sensed AET data in multi-objective calibration tends to improve model performance and decrease predictive uncertainty, as well as significantly improves parameter identification. Furthermore, AET single-variable calibration results show that the model would have performed well in simulating streamflow even without streamflow data. Moreover, each dataset included in this investigation responded differently. GLEAM_3.6b and GLEAM_3.6a performed the best, followed by FLDAS and PML_V2, while MOD16A2 was the least performing dataset. Thus, this research supports the use of remotely sensed AET in the calibration of hydrological models as a best practice. 