bluuebunny/crossref_metadata_2025 huggingface dataset:
Data-driven Estimation of Cloud Effects on Surface Irradiance atXianghe, a Suburban Site on the North China Plain
Authors: Liu Mengqi , Zhang Jinqiang , Shi Hongrong , Fu Disong , Xia Xiangao
Published: March 2024

Clouds are a dominant modulator of the energy budget. The cloud shortwave radiative effect at the surface (CRE) is closely related to the cloud macro- and micro-physical properties. Systematic observation of surface irradiance and cloud properties are needed to narrow uncertainties in CRE. In this study, 1-min irradiance and Total Sky Imager measurements from 2005 to 2009 at Xianghe in North China Plain are used to estimate cloud types, evaluate cloud fraction (CF), and quantify the sensitivities of surface irradiance with respect to changes in CF whether clouds obscure the sun or not. The annual mean CF is 0.50, further noting that CF exhibits a distinct seasonal variation, with a minimum in winter (0.37) and maximum in summer (0.68). Cumulus occurs more frequently in summer (32%), which is close to the sum of the occurrence of stratus and cirrus. The annual CRE is –54.4 W m–2, with seasonal values ranging from –29.5 W m–2 in winter and –78.2 W m–2 in summer. When clouds do not obscure the sun, CF is a dominant factor affecting diffuse irradiance, which in turn affects global irradiance. There is a positive linear relationship between CF and CRE under sun-unobscured conditions, the mean sensitivity of CRE for each CF 0.1 increase is about 1.2 W m–2 [79.5° < SZA (Solar Zenith Angle) < 80.5°] to 7.0 W m–2 (29.5° < SZA < 30.5°). When clouds obscure the sun, CF affects both direct and diffuse irradiance, resulting in a non-linear relationship between CF and CRE, and the slope decreases with increasing CF. It should be noted that, although only data at Xianghe is used in this study, our results are representative of neighboring areas, including most parts of the North China Plain.
CAMELS-CZ: A catchment attribute database for hydrological and climatological studies using a large sample of catchments
Authors: Jenicek Michal , Tyl Radovan , Nedelcev Ondrej , Ledvinka Ondrej , Šercl Petr , Bernsteinová Jana , Langhammer Jakub
Published: March 2024

Hydrological methods based on the analysis of data from a large sample of catchments with different characteristics (large-sample hydrology; comparative hydrology) allow a comprehensive analysis of the hydrological regime and thus a description of hydrological variability and change in the components of the water balance. These methods provide insight into hydrological processes shaped by environmental and climatic factors and allow more general conclusions to be drawn. However, besides climate and runoff data, catchment attributes, such as geology, soils, topography and vegetation, are essential for effective hydrological behaviour analysis. For these reasons, the global hydrological community has recently developed a number of freely available large-scale datasets known as CAMELS (Catchment Attributes and MEteorology for Large-sample Studies), which provide catchment attributes, as well as hydrological and meteorological time series, in a comparable structure at national scales. The aim of this contribution is to present the current state of preparation of the CAMELS database for Czechia (CAMELS-CZ) as a reference data platform for analysis and modelling, using a large sample of catchments.The database contains 389 catchments in Czechia maintained by the Czech Hydrometeorological Institute (CHMI) for which daily runoff data are available for at least 30 years. Catchments cover a variety of elevations (200–1600 m a.s.l) and runoff regimes (from pluvial to nival). Climate attributes were calculated from newly created daily climate grids (mean daily precipitation, mean daily air temperature) available in spatial resolution 1 km. Vegetation attributes are calculated based on Landsat data and the Corine Land Cover database. Soil texture database, hydraulic soil characteristics and geology maps are used for soil and geology attributes calculation. The subset of the catchments included in the upcoming CAMELS-CZ database has already been used for several purposes, mostly in mountain areas to analyse changes in snow cover and their influence on both low and high flows. For this subset, simulations of the conceptual hydrological model have been performed and used. The future goal is to prepare runoff simulations for all catchments included in the CAMELS-CZ database which will be publicly available for use among the hydrological community.
The role of anti-repeating earthquakes in seismic sequences and swarms
Authors: Cesca Simone , Niemz Peter , Dahm Torsten , Ide Satoshi
Published: March 2024

Repeating earthquakes have overlapping rupture patches, similar focal mechanism and magnitudes. They are often detected based on highly similar waveforms using template matching techniques, which help to reconstruct complex sequences and swarms. Here, we investigate earthquakes with highly anti-correlated waveforms. Such poorly known observation implies the occurrence of reversed seismogenic processes at close hypocentral locations. We introduce the terms true and quasi anti-repeating earthquakes to denote cases affecting the same rupture patch or neighboring patches, respectively. We report about a number of observations of anti-repeating earthquakes in different environments, such as volcano, induced and intermediate-depth seismicity, and then review conceptual models to explain them. Some of these observations occurred during seismicity unrests, in the form of seismic sequences and swarms. Both true and quasi anti-repeating earthquakes are indicators for stress perturbation transients or local stress heterogeneities, often controlled by fluid migration processes. Therefore, their analysis may help the identification and tracking of fluids in the subsurface.
Light and temperature limitation of poleward coral reef expansion during past warm climates
Authors: Kruijt Anne , Brachert Thomas , Middelburg Jack , Sluijs Appy
Published: March 2024

The latitudinal range of shallow-water tropical corals is controlled by temperature, and presently limited to waters warmer than 16-18 °C yearround. However, even during Cenozoic climates with such temperatures in polar regions, coral reefs are not found beyond >50° latitude. Here, we test the hypothesis that daily available solar radiation limited poleward expansion of coral reefs during warm climates, using a new box model of shallow marine coral calcification. Our results show that calcification rates start to decline beyond 40° and more quickly beyond 50°, suggesting that winter light intensity and day length prohibits further poleward expansion. This implies that fossil coral reef distribution is not a robust proxy for water temperatures and that poleward expansion of reefs is not an expected carbon cycle feedback of climate warming.
Carbon cycling in coexisting marine ecosystems: Cold seeps and coral reefs in Northern Norway
Authors: Sert Muhammed Fatih , Dølven Knut Ola , Petters Sebastian , Kekäläinen Timo , Jänis Janne , Corrales-Guerrero Jorge , Ferré Bénédicte
Published: March 2024

Cold seeps and cold water corals (CWCs) coexist on Northern Norway's continental shelf at the Hola trough between Lofoten and Vesterålen. Here, cold seeps release methane from the seabed, yet only a limited amount reaches the atmosphere. The remaining methane dissolves and disperses in nearby seeps. Methane is unreactive for most microorganisms in the water column, yet it is a unique energy and carbon source for methane-oxidizing bacteria (MOB). MOBs metabolize methane and release carbon dioxide as the end product of oxidation. Increasing carbon dioxide may constrain pH-sensitive CWCs in the region. We investigated the biogeochemistry of carbon, carbon isotopes, nutrients, dissolved organic matter (DOM) compositions and microbial diversity through water column profiles and water samples collected in June 2022. Preliminary results indicated that elevated methane increases dissolved inorganic carbon concentrations and modifies carbon isotopic compositions. Additionally, DOM compositions implied a positive correlation between prokaryotic diversity and protein-like DOM components at cold seeps and the entire water column near CWCs, suggesting analogous microbial modifications. Our preliminary conclusion suggests cold seeps and CWCs symbiotically coexist in Northern Norway continental shelves; however, enhanced water temperatures and consequent increase in methane release at cold seeps may mitigate the functioning of CWCs in future.This study is supported by the Research Council of Norway, project number 320100, through the project EMAN7 (Environmental impact of Methane seepage and sub-seabed characterization at LoVe-Node 7).
Adaptation of the SWIM hydrological model for forecasting the flow of the Zhabay River during floods/floods.
Authors: Nurbatsina Aliya , Tursunova Aisulu , Makpal Kanay , Salavatova Zhanat , Didovets Iulii
Published: March 2024

This study examines climate and hydrology changes in the Zhabay River basin in Kazakhstan and their impact on potential floods in the city of Atbasar. There has been a sustained increase in air temperature in the region since 2000. Significant events, such as the severe flood in 2014 and destructive waves in 2017, have posed a threat to the lives of Atbasar residents.Utilizing hydraulic modeling with HEC-RAS, researchers determined an extreme hazard level in the eastern part of the city and a high level in the south. Climate change forecasts for 2030 and 2040 indicate further temperature and precipitation increases in the Zhabay River basin, potentially leading to intensified snowmelt and increased precipitation.The hydrological model SWIM was modified to adapt to the conditions of the plains rivers in Kazakhstan. The study evaluated the model's potential for short-term operational hydrological forecasting. Results demonstrated the effective reproduction of flow dynamics by the SWIM model, aligning with actual observations. SWIM proved promising for operational forecasting of water regimes in Kazakhstan's plains rivers. The article also provides an assessment of short-term hydrological forecasts using the SWIM model, showing high accuracy during flood periods, making it valuable for operational forecasting of water discharge and volume.This research is intended for decision-makers in water resource management under changing climate conditions. The findings are also useful for water supply and emergency services to take measures for population protection and infrastructure development.
Generation of secondary gravity waves in idealized UA-ICON simulations
Authors: Zülicke Christoph , Amiramjadi Mozhgan , Borchert Sebastian
Published: March 2024

Gravity waves are an important driver of the circulation in the mesosphere / lower thermosphere and connect it to the atmospheric layers below. This vertical coupling is realized in multiple steps – primary waves rise, break and initiate secondary waves, which further rise. We study this process for stationary mountain waves in idealized simulations with the upper-atmosphere extension of the ICON model. The setup is for constant wind and stratification up to 120 km, where a sponge layer begins. In a series of simulations with various winds and mountain sizes, we follow the evolution of mountain waves including their breaking. Particular focus is on the diagnosis of wave-mean flow interaction and the associated generation of secondary gravity waves. In the vertical wavenumber spectra we find three peaks of them, all associated with lower frequency and longer horizontal wavelengths than the primary mountain wave. The parameters of primary and secondary waves are closely correlated, which adds to the understanding of multi-step vertical coupling.
Explaining agricultural land use changes in Spain (2004 – 2021): Markets, climate and water resources.
Authors: Arbonès Domingo Gabriel , De Stefano Lucia , Garrido Alberto
Published: March 2024

In Spain, from 2004 to 2021, irrigation has increased by 500,000 hectares, the percentage of cultivated land with irrigation has increased from 18% in 2004 to 23% in 2021. The literature points to intensive irrigated agriculture as one of the main causes of the destruction of biodiversity, the worsening of the quality of water bodies, changes in the rural economy, among others. The study analysis the dynamics of land use changes in Spain particularly in irrigated crops, from 2004 to 2021 at provincial level. It aims to understand and promote sustainable land use transitions by identifying factors influencing farmers' decisions in altering land use and crop surfaces. To this end, several public open-access databases were used to analyse, on one hand, the land use changes at a detailed level, and on the other hand, guided by the literature to examine the factors behind the observed land use change. Findings reveal agricultural intensification trends in Spain, marked by the abandonment of less productive croplands and the intensification of highly productive lands, through the implementation of irrigation. The intensification, driven by the introduction of irrigated woody crops, mostly olives, vineyards, and almonds, predominantly occurred in the water-constrained southern region of the country. This was achieved by overcoming water limitations through increased exploitation of groundwater, and the widespread adoption of drip irrigation technology. Additionally, market trends driving increased demand for these commodities and changes in the Common Agricultural Policy (CAP) have further contributed to their expansion. We explain why some provinces intensify, via more irrigated and intensive crops, and reduce cultivated land, whereas others intensify and expand the total cultivated land. The study suggests that agricultural land change is a complex dynamic process, resulting from a combination of policy impact, market incentives, mature technologies, available resources and changing climate.
Analysis of active fault morphotectonic behavior and seismic deformation during the September 2022 earthquakes in eastern Taiwan
Authors: Xu Jun-Yang , Hsu Yung-Wei , Chang Kuo-Jen
Published: March 2024

Taiwan situated on an active orogenic between the Eurasian plate and the Philippine Sea plate with an annual contraction rate of >8 cm, possesses therefore high seismicity and frequent geological hazards. Furthermore, many of the seismogenic faults pass across dense population areas and cause severe damages. In September 2022, several large earthquakes occurred in Longitudinal Valley, caused more than 100 casualties and damage roads, bridges and houses. However, exception of a few apparent surface cracks, the location, total length and actual deformation of the faults remain incomplete in most areas. In order to better constrain deformation and faulting behavior and potential threats, we focus on the Longitudinal Valley fault and Central Range fault in eastern Taiwan. To better estimate ground deformation around the active fault, large-area high-resolution geoinformatic datasets before and after the earthquake are critical. In this study, we use DMC aerial images, taken in April and September 2022, to produce DTM and orthomosaic images. Based on paired orthoimages before and after the earthquake, the particle image velocimetry (PIV) method was used to calculate the horizontal ground deformation. Vertical displacements near the fault were estimated from digital terrain models (DTM) of differences (DoD) pre- and post-earthquake. The results showed that the maximum horizontal displacement was greater than 2-3 meters and was been verified on field.
Operational hydrodynamic modeling as a tool to predict risks on underwater cultural heritage sites. Demonstration for the Algarve Coast.
Authors: Garzon Juan L. , Mills Lara , Martins Flávio
Published: March 2024

Submerged underwater cultural heritage (UCH) provides insight into past human behavior and history and thus the preservation of these artifacts at the site of discovery is crucial. However, marine environmental conditions such as physical, chemical, and biological processes directly impact the degradation of these underwater historical sites. Under the frame of the Horizon Europe project THETIDA (Technologies and methods for improved resilience and sustainable preservation of underwater and coastal cultural heritage to cope with climate change, natural hazards and environmental pollution), which runs between 2023 and 2026, the current work aims to demonstrate the suitability of process-based numerical models to (1) predict in real-time hazards threatening UCH sites associated with currents and sediment abrasion and (2) to estimate the risks associated with these oceanic conditions. This general approach is demonstrated for the Coast of Algarve (southern coast of Portugal), focusing specifically on the B-24 wreck. This WWII bomber airplane rests on the bottom of the coastal shelf at 20 m deep and approximately three kilometers offshore of Praia de Faro. The methodology couples a wave model (SWAN) to an existing operational hydrodynamic system SOMA powered by the MOHID model, which will provide inputs to run a non-cohesive sediment transport model. In-situ measurements and laboratory experiments will be used to determine deterioration rates that will provide insights into risk categorization and impacts on UCH sites. The final product will be a demonstrative operational ocean model for UCH management, assessment, and emergency response.Acknowledgement: This research has been funded by the European Union’s Horizon Europe research and innovation programme under THETIDA project (Grant Agreement No. 101095253) (Technologies and methods for improved resilience and sustainable preservation of underwater and coastal cultural heritage to cope with climate change, natural hazards and environmental pollution). The authors also acknowledge Fundação para a Ciência e Tecnologia (FCT), under the project LA/P/0069/2020 granted to the Associate Laboratory ARNET and UID/00350/2020 CIMA (https://doi.org/10.54499/UIDP/00350/2020).
Assessment of landslide, Sediment Production and Disaster Prevention in in mountainous watersheds in Taiwan
Authors: Hsu Yung-Wei , Xu Jun-Yang , Chang Kuo-Jen
Published: March 2024

            Since the Chi-Chi earthquake in 1999 and the subsequent Typhoon Morakot in 2009, mass movements such as landslides have become a prominent focus of study. Particularly noteworthy are significant disasters like the Shiaolin Village debris flow and the Yushuishi debris flow in the Southern Cross-Island Highway, which have had a substantial impact on the environment and people's livelihoods. Consequently, the issue of sediment-related disasters has continued to gain attention and expand in recent years. However, estimating the volume of colluvium debris on the slope within the watershed, as well as understanding the transport and deposition of materials in the river channels, poses a challenging issue. This challenge arises from the complexity of geological factors and causes, the prolonged duration of these processes, and the difficulty of implementing engineering solutions. Therefore, effective estimation of the volume, transport, and deposition of sediment, especially in high-risk areas, along with the assessment of potential disaster risks, can be achieved with minimal human resources. This approach can provide effective early warning and reduce the impact of disasters, preventing them before they occur.           The vigorous development of geospatial information technology has not only yielded positive results in land monitoring but has also gradually extended to other application fields. Hazard monitoring is one of its crucial applications. Geospatial information can be obtained through surveying and mapping technology, and through multi-temporal geospatial data, the production, migration, and accumulation of debris deposits can be quantitatively evaluated in a reasonable time and space within the catchment scale.         For these purposes, this study focuses on the Laonongshi catchment, which has experienced past disasters and still retains a substantial amount of residual colluvium on its slopes. This study is dedicated in multi-temporal aerial photogrammetry and dataset generation. By combining surface geological investigations with various existing remote sensing images.Detailed DTMs and Orthomosaic images were established, since pre-Typhoon Morakot in 2009, and post events, including 2009, 2013, 2015, and 2018 with 2 meter resolution. The result reveals significant changes in the river channel and numerous reactivation of landslide debris accumulation.
Mapping the end of the world: Understanding plausible routes to collapse from 2°C of warming
Authors: Stephenson Sam , Kemp Luke
Published: March 2024

Climate risk is systemic risk. Despite this, extreme risk cascades from climate change are underexplored. This is a mistake since such cascades are likely to occur even at relatively low temperature rises of 1.5-2°C. Such heating risks triggering six or more tipping elements in the Earth system.  Here we use a novel form of expert elicitation and systems mapping to trace out potential paths from climate impacts to societal collapse at 2°C of warming. We contacted 8 experts from a range of different fields, including climatology, earth systems science, and existential risk studies, and had them compose systems diagrams of the most likely scenarios in which expected climate impacts cascade into widespread systems failures. We then compared and synthesised these to identify key, common feedbacks and pathways. These include food crises and extreme weather events undermining state legitimacy and triggering socio-political violence. Climate resilience efforts need to account for such extreme cascades.  
Impact of biomass burning emission variability on precipitation over tropical oceans
Authors: Zhang Xiaoyan , Xu* Xiyan , Jia Gensuo , Liang Yue
Published: March 2024

Numerical simulations mostly constrain the total amount of biomass burning aerosols but rarely prescribe the realistic emission variability. Ignoring high heterogeneity of emission variability may lead to uncertainties in climate projections. Based on the Community Earth System Model version 2 Large Ensemble Community Project (CESM2-LE), we investigated the impact of interannual variability of biomass burning emissions on tropical precipitation and extremes. Our results revealed that global carbonaceous aerosol emission was 180-320 Tg over the period 1990-2020. Tropical regions (30°S-30°N) had the largest emission flux and variability. Higher interannual variability triggered increasing precipitation and extremes in tropics where spatial heterogeneity of precipitation anomalies can be detected. More precipitation and northward ITCZ shift occurred in central and western Pacific Oceans, while precipitation reduction together with southward ITCZ rain-belt over eastern Pacific and Atlantic Basins. The asymmetries were attributable to weakened Walker circulation and its uplifting branch tilted toward the Southern hemisphere. Correspondingly, nonlinear aerosol-cloud interactions increased (reduced) the total and high cloud cover over the southern central-western Pacific (eastern Pacific and Atlantic) Oceans. Convective activities were then strengthened (weakened) due to lower (higher) outgoing longwave radiation at top of atmosphere, which drove the cross-equatorial heat transport variations, and ultimately led to southward (northward) shift of ITCZ. Our results revealed the synergistic mechanisms between biomass burning emission variability, radiation and cloud characteristics, and large-scale circulation modes, thereby gaining new insights into the tropical hydrological cycle.
Driving of the QBO by gravity waves and global-scale waves: a comparison between satellite data and reanalyses
Authors: Ern Manfred
Published: March 2024

The quasi-biennial oscillation (QBO) is the dominant mode of atmospheric variability in the tropical stratosphere. It has effects on the weather and climate in the tropics and the extratropics. The QBO is a wave-driven circulation pattern of alternating easterly and westerly winds that propagate downward with time. Climate models have problems in simulating a realistic QBO because of problems in simulating the QBO wave driving in a realistic way. Both mesoscale gravity waves and global-scale tropical waves contribute to the wave driving of the QBO, but the relative contribution of the different wave types is not well known.For the period 2018 until mid 2023 we estimate the QBO driving by gravity waves from the residual in the TEM momentum budget for three modern reanalyses (ERA5, MERRA2, and JRA55) and compare absolute values of the QBO gravity wave driving with estimates derived from temperature observations of the SABER satellite instrument. Qualitatively, good agreement is found, but MERRA2 gravity wave driving seems to be too strong in the upper stratosphere. Further, we derive the QBO eastward driving by global-scale Kelvin waves for the reanalyses and from SABER observations. The QBO eastward driving by Kelvin waves is similarly strong as the gravity wave eastward driving, and again good agreement is found between SABER and the reanalyses. In the reanalyses below 30km the total westward driving of the QBO by global-scale waves, however, seems to be weaker than the estimated gravity wave driving.
Spatiotemporal characteristics of drought in the Yili River basin in Northwest China over the past 40 years
Authors: Huang Mengzhen , Lu Ruijie , Li Peiru , Han Yutong
Published: March 2024

The Yili River basin is commonly referred to as a "wet island" in the Central Asian Dry Zone. It functions as a vital security barrier in the western part of China. Droughts frequently occur in the basin due to global change and pose a significant threat to food security and ecological stability in the region. Currently, droughts in the basin have not received the attention they deserve, and the mechanisms behind the occurrence, development, and impacts of drought in the basin have not yet been clarified. Based on the Standardized Precipitation Evapotranspiration Index (SPEI), this research identified drought events over the past 40 years, extracted drought characteristics and drought trends, and explored future drought. The following results were found: 1) The basin has experienced frequent wet and dry changes on monthly and seasonal scales, and entered a period of high drought since 2005, specifically the successive severe droughts of 2007-2009 and 2012-2015. 2) There were drought events approximately one-quarter of the time in the basin. Each drought event lasted an average of 2.23 months with a medium intensity. The most prominent droughts occurred in spring and summer. Droughts in the middle and southwest of the basin had short durations but higher intensities, which significantly impacted the area. 3) Over the last 40 years, there has been a general increase in aridity in the basin, especially in spring and summer. The aridity trend was more severe in the northwestern part. 4) In the future, annual drought is predicted to decrease but will increase in summer. It’s recommended that emergency management of drought disasters in the basin be strengthened and, in particular, to improve the monitoring, early warning and prevention in summer.
New horizons for the Data Store Infrastructure at ECMWF
Authors: Lopez Alos Angel , raoult Baudouin , correa Ricardo , obregon Andre , stewart Chris , varndell James , comyn-platt Edward , damasio da-costa Eduardo , Zanacchi Marcus
Published: March 2024

Since its official launch in 2018 supporting the implementation of the Copernicus Climate Change Service (C3S), the Climate Data Store (CDS) software infrastructure has evolved in many ways driven by an expanding catalogue of resources, a growing user community and the evolution of technologies and standards. On 2020 a twin instance, the Atmosphere Data Store (ADS), as support of the Atmosphere Monitoring Service (CAMS) was released. Since then, Infrastructure was renamed as Climate and Atmosphere Data Store (CADS). Combined, CDS and ADS, provide nowadays service to more than 270k registered users, delivering over 130 TBs of data on daily average in the form of more than 700k processed requests.In 2024, a modernized CADS will take over. A configurable framework built on cloud oriented and state-of-the-art technologies providing more scalable, wider, and open access to data and services which will foster the engagement with a broader user community and will facilitate interaction with different platforms in the future EU Green Deal Data Space.Despite changes, CADS foundational principles of simplicity and consistency remains along with FAIR. A rigorous content management methodology is at the core of the system, supported by automatic deployment tools and configuration files that range from web portal content to metadata, interactive forms, dynamic constraints, documentation, adaptors, and quality control. This versatile mechanism provides huge flexibility for adaptation to different standards and FAIR principles. In addition to improved capabilities for discovery, search and retrieve, the modernized system brings new or re-engineered components aiming to improve the usability of resources,  such as compliant OGC APIs, integrated and interactive Evaluation and Quality Control (EQC) function, open-source expert python packages (earthkit) for climate and meteorological purposes able to deploy & run anywhere, or Serverless Analysis-Ready Cloud Optimized (ARCO) Data and Metadata Services supporting responsive WMS/WMTS interfaces.Modernization also involves the underlaying Cloud Infrastructure which aligned with the ECMWF’s Strategy for a Common Cloud Infrastructure (CCI) brings extended compute and storage resources and more importantly, closer, and efficient access to ECMWF resources, data, and services.All new capabilities combined power a new generation of interactive user applications, training material, EQCs functions, and efficient access mechanisms to large data volumes driven among others by ML/AI requirements.  Here we describe the new horizons that the modernized Data Store infrastructure open to users, introduce the broad spectrum of functionalities, open-source code, and material currently available and we open for debate the expectations and requirements that will foster the future evolution of the different components of the infrastructure.
Collocation of multi-source satellite imagery for ship detection based on Deep Learning models
Authors: La Tran-Vu , Pham Minh-Tan , Chini Marco
Published: March 2024

The development of the world economy in recent years has been accompanied by a significant increase in maritime traffic. Accordingly, numerous ship collision incidents, especially in dense maritime traffic zones, have been reported with damage, including oil spills, transportation interruption, etc. To improve maritime surveillance and minimize incidents over the seas, satellite imagery provided by synthetic aperture radar (SAR) and optical sensors has become one of the most effective and economical solutions in recent years. Indeed, both SAR and optical images can be used to detect vessels of different sizes and categories, thanks to their high spatial resolutions and wide swath.To process a mass of satellite data, Deep Learning (DL) has become an indispensable solution to detect ships with a high accuracy rate. However, the DL models require time and effort for implementation, especially for training, validating, and testing with big datasets. This issue is more significant if we use different satellite imagery datasets for ship detection because data preparation tasks will be multiplied. Therefore, this paper aims to investigate various approaches for applying the DL models trained and tested on different datasets with various spatial resolution and radiometric features. Concretely, we focus on two aspects of ship detection from multi-source satellite imagery that have not been attentively discussed in the literature. First, we compare the performance of DL models trained on one HR or MR dataset and those trained on the combined HR and MR datasets. Second, we compare the performance of DL models trained on an optical or SAR dataset and tested on another. Likewise, we evaluate the performance of DL models trained on the combined SAR and optical dataset. The objective of this work is to answer a practical question of ship detection in maritime surveillance, especially for emergency cases if we can directly apply the DL models trained on one dataset to others having differences in spatial resolution and radiometric features without the supplementary steps such as data preparation and DL models retraining.When dealing with a limited number of training images, the performance of DL models via the approaches proposed in this study was satisfactory. They could improve 5–20% of average precision, depending on the optical images tested. Likewise, DL models trained on the combined optical and radar dataset could be applied to both optical and radar images. Our experiments showed that the models trained on an optical dataset could be used for radar images, while those trained on a radar dataset offered very poor scores when applied to optical images.
Pond emissions of CO2 and CH4 in a rewetted peatland 
Authors: Kudsk Karoline , Carlsen Kathrine Lindblad , Larsen Klaus Steenberg , Christiansen Jesper Riis
Published: March 2024

Natural peatlands are crucial for global terrestrial carbon storage but have historically been extensively drained. Mitigating enhanced greenhouse gas (GHG) emissions linked to peatland drainage often involves rewetting, leading to pond formation. While rewetting is perceived to contribute to net GHG reduction, observational data of carbon dioxide (CO2) and methane (CH4) emissions from these restored ecosystems remains highly variable and overall insufficient. Ponds created after rewetting may be hot spots for CH4 emissions and this study focused on assessing net CO2 and CH4 emissions from a pond in a rewetted peatland over a one-month period in 2023.The field study took place on a former fen at Mårumhus Pond in Gribskov, Denmark, rewetted in 2008 by clear-cutting a Norway spruce plantation and blocking ditches. This intervention resulted in a permanent pond covering the entire former fen area, with water depths ranging from approximately 0.5 to 1 meter. CO2 and CH4 fluxes were measured using automated chambers (AC) and manual bubble traps (BT). The study, conducted from September 19th to October 18th, 2023, involved eight AC and BT devices deployed along a 50-meter transect perpendicular to the pond's shore.Throughout the measurement period, the daily average CO2 efflux from all eight AC chambers ranged between 3663 – 9074 mg CO2 m-2 d-1. Concurrently, daily average net CH4 emission from these AC chambers ranged from 224 – 1231 mg CH4 m-2 d-1, contrasting significantly with the average BT-derived CH4 flux range of 30 – 91 mg CH4 m-2 d-1. AC measurements indicated ebullition as the primary emission pathway, with one main hotspot across the transect, a pattern also observed by the BT. Interestingly, CO2 and CH4 emission patterns showed no correlation with water depth but demonstrated a clear response to the disruption of thermal stratification during the measurement period, attributed to wind-driven mixing of the water column. CH4 emissions measured with the AC increased during sudden air pressure drops.AC and BT displayed substantial differences in measured fluxes, with AC showing CH4 fluxes nearly ten times higher than BT, which also failed to capture valid CO2 emissions. These difference can be attributed to method specific limitations, which will be discussed. The observed variations in CO2 fluxes using the AC method align with literature values, while CH4 emissions are notably higher. This study underscores the need to include spatiotemporal variations in both fluxes and environmental drivers and emphasizes the need for further research and method development of GHG emissions from ponds in rewetted peatlands, as these environments may serve as significant hotspots for CH4 emissions.
Analysis of Aerosol Pollution over North-Western Nigeria
Authors: Sa’id S. Rabia , Hussain Shettima
Published: March 2024

This paper analyzes the optical properties and air mass trajectory of aerosol pollution over North-West (NW) Nigeria. The paper studied the Aerosol Optical Depth (AOD), Angstrom Exponent (AE), Single Scattering Albedo (SSA) and air mass trajectory analysis of aerosols pollution over NW Nigeria from 2018 to 2022. For this purpose, the use of satellite products from Ozone Monitoring Instrument (OMI), the Moderate Resolution Imaging Spectroradiometer (MODIS), and back trajectories of air movements calculated using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) were employed. AOD values were found to reach peak values (~1 at 500 nm) across the years in the study except in 2020, which, showed a steep decline in AOD values during the period. It is surmised that the decline might have been due to the lock down due to Covid19 when vehicular movement that generate particulate matter and black carbon, construction that generate dust plumes were minimal. Analysis of the optical characteristics of the aerosols studied, supported the observation that the pollution consists of mainly Saharan dust and anthropogenic aerosols with a well-defined seasonal cycle. This assumption was confirmed by HYSPLIT backward trajectories and MODIS images. Keywords: MODIS, Aerosol Optical Depth, Single Scattering Albedo, Angstrom Exponent, Ozone Monitoring Instrument, HYSPLIT.
No evidence for large mercury release from the Greenland Ice Sheet: recent conclusions on global mercury budget invalidated. 
Authors: Jørgensen Christian Juncher , Søndergaard Jens , Larsen Martin Mørk , Kjeldsen Kristian Kjellerup , Rosa Diogo , Sapper Sarah Elise , Heimbürger-Boavida Lars-Eric , Kohler Stephen G. , Wang Feiyue , Gao Zhiyuan , Armstrong Debbie , Albers Christian Nyrop
Published: March 2024

Local glaciers and ice caps in the Northern Hemisphere and the Greenland Ice Sheet (GrIS) have recently been suggested to be important parts of the Arctic mercury (Hg) budget. Based on ice-core data, the recently estimated total glacial Hg pool is approximately 2,400 tons, approximately 97% of which is in Greenland1. With Hg concentrations in pre-industrial ice being significantly lower than in ice formed during the 19th and 20th centuries, the dominating source of glacial Hg and input to the Arctic Hg budget is ascribed to long-range transport of anthropogenic Hg emissions2.Alarming concentrations of Hg in meltwater from the western margin of the GrIS were recently reported3. With Hg concentrations reported as being 100 - 1000 times higher than what is known for other freshwater systems of Greenland and a postulated increase in Hg export to downstream environment following climate warming and asserted global importance of Hg fluxes from the GrIS, these extraordinary concentrations and conclusions calls for independent verification.In our current study4, we expand the sampling of subglacial meltwater from 21 representative outlets at GrIS in 2021 and 2022 to get a better scientific basis for conclusions on the magnitude of glacial Hg sources in Greenland. Results from our study consistently show that both total and dissolved Hg concentrations in glacial meltwater over space and time are very low (generally
Mapping of climate to flood extremes in the European Alps: a multidisciplinary approach
Authors: Viglione Alberto , Arnone Enrico , Corti Susanna , Ferguglia Olivia , Giuntoli Ignazio ,  von Hardenberg Jost , Lombardo Luca , Mazzoglio Paola , Palazzi Elisa
Published: March 2024

As our climate system climbs through its current warming path, temperature and precipitation are greatly affected also in their extremes and there is a general concern about the effects on river floods. While a wide body of literature on the detection of flood changes is available, the identification of their underlying causes (i.e. flood change attribution) is still debated. In this work, we aim at better understanding how floods of different kind are related to climate extremes (of precipitation and temperature) and how these extremes are related to large scale predictors (e.g. climate oscillations, teleconnections). The study area is the Greater Alpine Region, which is an ideal laboratory for analysing complex effects of climate on floods because of the interplay of heavy precipitation and snow processes in controlling flood generation, and also because the European Alps divide the Mediterranean and Continental Europe with different responses to climate oscillations. Through a novel integrated modeling chain, we aim at identifying the climate extreme indices that better relate to river floods, the large-scale climate phenomena controlling their dynamics, their expected modifications due to climate change and the associated uncertainties. The research plan of a multidisciplinary team of climatologists and hydrologists will be presented together with preliminary results. We believe that this research will strengthen our knowledge on flood risk in the future and contribute to improve existing methods for disaster risk assessment and management.
Waveform behaviour in pressure varying debris flow models
Authors: Mckinnell Daniel , Johnson Chris
Published: March 2024

Debris flows are composed primarily of densely packedparticles of rock, surrounded by water. Excess pressure (that is greaterthan hydrostatic) in the water decreases the stress supported thegranular matrix, and correspondingly reduces the overall frictionalresistance of the debris flow, allowing for larger velocities. Waves inthese flows can increase their run-out by creating deeper fronts of highfluid concentration and high fluid pressure. Continuum models of debrisflows have been refined with the inclusion of variation in excess fluidpressure. In this talk we will aim to examine the mechanisms in thismodel by studying the idealised case of flow on an inclined plane. Wewill solve for periodic waveforms to show the impact of varying fluidpressure throughout the wave, and examine unexpected behaviour withinthe model.
Midlatitude heatwave variability modulated by a shifting storm track
Authors: Wicker Wolfgang , Russo Emmanuele , Domeisen Daniela
Published: March 2024

Both the circulation response to climate change as well as internal atmospheric variability are marked by a meridional displacement of the extratropical storm track. It remains to be quantified how such changes in the storm track modulate the occurrence of heatwaves. We combine a composite analysis of reanalysis data with idealized model experiments to investigate the response in heatwave frequency to variations in the storm track latitude in two different datasets. In the idealized model, a forced poleward storm track shift leads to an increase in upper-tropospheric Rossby wave phase speed, and vice versa, which in turn reduces and increases heatwave frequency and duration across the mid-latitudes. A similar relationship between storm track latitude, Rossby wave phase speed, and heatwave duration is found for internal variability in reanalysis data. However, in reanalysis, a reduction in phase speed does not necessarily lead to an increased heatwave frequency due to geographically phase-locked wave trains induced by zonal asymmetries. These results shed new light on the dynamical drivers for heat extremes.
SCS-CN parameter determination from observed rainfall runoff data. A critical review.
Authors: Soulis Konstantinos , Palli Gravani Stergia , Kalivas Dionissios
Published: March 2024

One the most difficult challenges in applied hydrology is predicting runoff in ungauged or poorly gauged watersheds. Thus, simple approaches for runoff estimation are especially useful in hydrologic applications. A simple, well established, and widely used technique for predicting the direct runoff depths of rainfall events is the Soil Conservation Service - Curve Number (SCS-CN) method. Due to its straightforward but well-proven approach, readily available and well documented environmental inputs, and incorporation of numerous variables influencing runoff generation into a single CN parameter, it quickly rose to prominence among engineers and practitioners. Tables can be used to identify the CN parameter values corresponding to prevailing soil, land cover and land management conditions. However, it is always better to estimate the CN value using observed rainfall-runoff (P-Q) data when available. Estimating appropriate CN values for additional soil – land cover conditions and additional regions is also critical for extending and updating the method’s documentation given that the SCS-CN approach is extremely sensitive to variations in the CN values.However, even when the CN value is determined from measured P-Q data, the estimated CN values vary substantially from storm to storm on any given watershed. For this reason, various methods to estimate the CN value characterizing each watershed have been proposed up to know, and many theories on the reasons behind the observed relationships between CN and P for each watershed have been stated. Though, after many years of research, there isn’t still a unique agreed method to estimate the CN values characterizing a watershed or a soil-land cover complex, while the proposed methods lead to different CN values and in many cases neglect spatial variability. Further, an increasing number of modified SCS-CN versions are continuously developed, and new parameters are introduced complicating the situation even more.Accordingly, this study attempts to collect, categorize, and systematically analyze the huge number of studies on SCS-CN method published in the last 30 years. We selected this period as 30 years ago, in 1993, R.H. Hawkins published his emblematic study on the “Asymptotic determination of runoff curve numbers from data” (J. Irrigat. Drain. Div. ASCE, 119(2): 334–345). In this review study, specific attention is given to the methods focusing on CN value determination from measured P-Q data. The advantages and limitations of the various approaches are investigated, as well as trends and gaps in existing literature. The analysed methods are classified and the main paths are identified. Based on the obtained results, conclusions on the current status are being made, and the more promising approaches are highlighted.  Then, ideas on future research pathways towards the target of a unified CN values determination approach are discussed.
Anoxic Ocean inhibited the formation of porphyry copper deposits
Authors: Sun Min , Wang Xiangsong , Zhao Guochun
Published: March 2024

Abundant porphyry copper deposits (PCDs) are distributed in the Central Asian Orogenic Belt (CAOB), but the majority are concentrated in the Circum-Balkhash and Tuva-Mongolia micro-continents (BM), limited deposits have been identified in the Circum Junggar Collage (CJC), the mechanisms that drive uneven distributions of PCDs remain controversial. We provide a compilation of published elemental and isotopic data of magmatic rocks from the CAOB, which show that the CJC arc rocks possess lower Cu concentrations, V/Sc and Sr/Y ratios, and zircon ∆FMQ values, but higher zircon δ18O values compared to the BM rocks, demonstrating the CJC rocks has lower porphyry ore potential and magmatic oxidation states that were triggered by the addition of reduced sediments. Substantial biogenic sediments within the accretionary complex belts in the CJC imply widespread anoxia of the Junggar ocean due to isolation from wider Paleo-Asian Ocean, which promoted the generation of reduced arc magmas and further inhibited the formation of PCDs. The arc magmatic oxygen fugacity shift indicates that the ocean redox state was recorded in the deep Earth and significantly control the generation of PCDs in arcs.Acknowledgements: The present study was financially supported by Hong Kong Research Grant Council Joint Laboratory Funding Scheme (JLFS/P-701/18), NSFC Major Project (41890831) and Hong Kong RGC grants (17307918 and 17308023), and HKU Internal Grants for Member of Chinese Academy of Sciences (102009906) and Distinguished Research Achievement Award (102010100). This work is a contribution of the Joint Laboratory of Chemical Geodynamics between the University of Hong Kong and Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. 