bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of global fire simulations in CMIP6 Earth system models
Authors: Li Fang , Song Xiang , Harrison Sandy , Lin Zhongda
Published: March 2024

       Fire is the primary form of terrestrial ecosystem disturbance globally and a critical Earth system process. So far, most Earth system models (ESMs) have incorporated fire modeling, with 19 out of them submitted fire simulations to the CMIP6. Transitioning from CMIP5 to CMIP6, much more models submitted fire simulations and the dominant fire scheme has evolved from GlobFIRM to the Li scheme. However, it remains unknown how well CMIP6 ESMs perform in fire simulations. This study provides the first comprehensive evaluation of CMIP6 fire simulations, through comparisons with multiple satellite-based datasets and the Reading Paleofire Database of global charcoal records (RPD).        Our results show that most CMIP6 models simulate the global amounts of present-day burned area and fire carbon emissions within the range of satellite-based products, and reproduce observed major features of spatial pattern and seasonal cycle as well as the relationships of fires with precipitation and population density, except for models employing the GlobFIRM fire scheme. Additionally, most CMIP6 models can reproduce the response of interannual variability of tropical fires to ENSO, except for some models incorporating the SPITFIRE fire scheme. From 1850 to 2015, CMIP6 models generally agree with RPD, with some discrepancies in southern South America before 1920 and in temperate and eastern boreal North America, Europe, and boreal Asia after 1990. Compared with CMIP5, CMIP6 has solved the serious issues of CMIP5 which simulates the global burned area less than half of observations, fails to capture the high burned area fraction in Africa, and underestimates seasonal variability. CMIP6 fire carbon emissions simulations are also closer to RPD. However, CMIP6 models still fail to capture the present-day significant decline in observed global burned area and fire carbon emissions partly due to underestimation in anthropogenic fire suppression, and fail to reproduce the spring peak in NH mid-latitudes mainly due to an underestimation of crop fires. Based on our findings, we identify potential biases in fire and carbon projection based on CMIP6 models. We also provide suggestions for the fire scheme development, and bias correction methods when generating multi-source merged ﬁre products.
Dynamic Interplay of Dune Patterns and Sediment Characteristics: Unraveling the Complex Nexus of Land Use and Environmental Responses in the Eastern Shore of Lake Wuliangsu ,China
Authors: Wang Zhuoran
Published: March 2024

In the sandy regions of the eastern shore of Lake Wuliangsu, the evolution of dune patterns and the response of sediment particle characteristics to land cover changes hold significant scientific importance. This study aims to delve into the variations in dune patterns in the region and explore the relationship between sediment particle characteristics and land cover dynamics. Through systematic analysis of remote sensing imagery and field measurements in the eastern sandy areas of Lake Wuliangsu, we unveil the trends in dune patterns over recent years. Our focus encompasses changes in the number, morphology, distribution,and spatial correlations of dunes. These data contribute to a more comprehensive understanding of the land cover evolution processes in the region. Simultaneously, sediment samples were collected, and particle size analysis methods were employed to study the soil particle size distributions. These particle size characteristics are believed to be closely associated with factors such as climate, hydrodynamics, landforms and land use changes. Our research aims to identify potential correlations between changes in sediment particle size and the evolution of dune patterns, providing a deeper understanding of environmental changes in the eastern sandy areas of Lake Wuliangsu. This study introduces innovative insights into the intricate relationships governing dune dynamics in sandy terrains and their interplay with environmental factors. We anticipate that our in-depth investigation of this unique area will provide valuable insights for land use and resource management in arid regions. Furthermore, it lays a solid scientific foundation for the conservation and sustainable development of desert ecosystems.
Methane seeps features characterization on the Moñito continental shelf, Colombian Caribbean, through a multi-scale and multi-method approach
Authors: Varzi Andrea Giulia , Galimberti Giulia , Micallef Aaron , Savini Alessandra , Ramirez Zapata Paula Andrea
Published: March 2024

When referring to gas in marine sediment, we mean natural gas trapped in the sub-bottom sediments and escaping from the sub-seafloor into the marine environments. Among gases, methane is the most common one, and may have diverse origins, including both thermogenic or microbial sources. Natural seepages are globally distributed, with notable occurrences along  continental margins. They significantly affect the local marine ecosystems and the surrounding substrate, other than being a wake-up call in terms of geohazards.Since the discovery of the Chuchupa and Ballenas fields in the 1970s, the offshore Colombian Caribbean has been considered a gas province mainly dominated by methane, most likely generated by microbial/thermogenic activities. Nevertheless, there is still little knowledge of this area. Since methane is a potent greenhouse gas, it is important to evaluate the contribution of seabed emissions to the global budget. This is particularly true when they are located in relative shallow waters since they represent an important source of the methane flux from lithosphere to hydrosphere and finally atmosphere. Moreover, methane-enriched environments are peculiar habitats and hot-spot of biodiversity.The Colombian project “Methane Seep Hunting: a multi-scale and multi-method approach” aims at developing a multi-scale and multi method approach to detect methane seeps, determine their current/past seepage activity, and identify their source using the state of art technology in the Colombian Caribbean. Specifically, it aims at the characterization of the methane seeps discovered in the Moñito continental shelf.Ship-based MEBS data collection over about 220 km2 of seafloor performed in May 2022 revealed the presence of more than 20.000 pockmarks, at places associated to the presence of flares in the water column. In addition, other positive morphologies have been recognized, depicting the presence of a past and/or present fluid flow system.Keywords: geomorphology; methane seeps; pockmarks; fluid flow system; Colombian Caribbean; tropics; climate change 
Magnetic map-making for advanced applications: Quantitative comparison of frequency dependent features, errors, and uncertainties in gridded magnetic data
Authors: Duff Patrick , Nielsen Aaron
Published: March 2024

Existing models of the Earth’s lithospheric magnetic field (e.g.; World Digital Magnetic Anomaly Map (WDMAM-2) and Earth Magnetic Anomaly Grid (EMAG2v3)) are composed of short wavelength information (< 100 km) from near-surface survey data and long wavelength information (> 300 km) from satellite data. In oceanic areas, compilations of ship trackline data provide the near-surface measurements used to construct global-scale gridded maps of the magnetic anomaly field. Although these maps have been used widely for tectonic and geodynamic studies, advanced applications, including complex inversions and the use of magnetics for alternative (to GPS) navigation, require renewed attention as to how gridded maps are made. Data selection, including detection of anomalous tracklines, knowledge of the sampling and power spectra of the potential field, quantification of uncertainty and an accurate representation of the gradients in the estimated field all represent areas of interest for advanced applications.
We approach the problem of magnetic map-making for advanced applications by developing a means of quantitative comparison of magnetic data which we apply to each length scale of the underlying magnetic measurements and interpolated grids as a function of potential field frequency (spatial wavelength). Magnetic anomaly maps of the same region generally reproduce comparable long wavelength features. Further comparison of these maps indicates that dominant differences occur at short spatial wavelengths. Coherence analysis provides a technique to make a wavelength dependent comparison quantitatively, which can be used for data selection as well as to measure length-scale dependent errors and uncertainties. Coherence can help to assess if individual tracklines are consistent with the overall dataset and could help determine if these tracklines should be included in a final map product. Such a methodology could help automate or semi-automate the trackline selection and grid generation procedure. An understanding of the uncertainty at different length scales provides important information for the development and tuning of navigation algorithms and can provide an analytical framework for understanding different methods of map construction. In areas with high-quality reference maps this type of analysis can help inform scale dependent uncertainty models.
Isotopic mapping of sedimentary organic matter in the northwestern Pacific marginal sea (Yellow Sea, East China Sea, East Sea)
Authors: Kim Seung-Hee , Lee Dong-Hun , Joo Huitae , Youn Seok-Hyun , Go Young-Shin
Published: March 2024

We investigated physio-chemical properties, sedimentary bulk elements (C, N, S contents and heavy metals concentration), and isotopic compositions (δ13C, δ15N, 87Sr/86Sr) in the northwest Pacific marginal sea (Yellow Sea, East China Sea and East Sea; R/V Tamgu 3 and 9, February in 2019) to trace the distribution, origin, and reactivity of sedimentary organic matter (OM). Together with hydrodynamic influence (mainly freshwater input) near Yellow Sea and East China Sea, the spatial patterns of sedimentary bulk elements consider that there may be the potential accumulation of natural/anthropogenic derived-OMs transported from regional (Korea-China) river systems. Furthermore, δ13C and δ15N values in surface sediments may be characteristic of the mixture of autochthonous (e.g., algae)/allochthonous (e.g., C3 plant, soil, fertilizer) origins, suggesting the discriminative source contribution on the sedimentary OM distributions. Especially, compared to the isotopic end-members reported from Korean and China river estuaries, isotopic signatures of sedimentary OM may be regarded as the discriminative contribution of various terrestrial derived-origins within the Yellow Sea and East China Sea. Further, 87Sr/86Sr ratio indicated discriminative weathering impact and terrestrial origin OM transportation within the Korean and China river estuaries. Hence, with respect to the increase of anthropogenic activities near northwest Pacific marginal sea, the source tracing approach estimated via the multi-isotopic mapping may provide important insights for effectively understanding dramatic change of biogeochemical OM cycles from water column to sediments.
Feature scale and identifiability: quantifying the information that point hydraulic measurements provide about heterogeneous head and conductivity fields
Authors: Hansen Scott K. , O'Malley Daniel , Hambleton James
Published: March 2024

We consider the optimal inference of spatially heterogeneous hydraulic conductivity and head fields based on three kinds of point measurements that may be available at monitoring wells: of head, permeability, and groundwater speed. We have developed a general, zonation-free technique for Monte Carlo (MC) study of field recovery problems, based on Karhunen-Loève (K-L) expansions of the unknown fields, whose coefficients are recovered by an analytical adjoint-state technique. This allows unbiased sampling from the space of all possible fields with a given correlation structure and efficient, automated gradient-descent calibration. The K-L basis functions have a straightforward notion of period, revealing the relationship between feature scale and reconstruction fidelity, and they have an a priori known spectrum, allowing for a non-subjective regularization term to be defined. We have performed automated MC calibration on over 1100 conductivity-head field pairs, employing a variety of point measurement geometries and quantified the mean-squared field reconstruction accuracy, both globally and as a function of feature scale.We present heuristics for feature scale identification, examine global reconstruction error, and explore the value added by both groundwater speed measurements and by two different types of regularization. We show that significant feature identification becomes possible as feature scale exceeds four times measurement spacing and identification reliability subsequently improves in a power law fashion with increasing feature scale.
The Observational Products for End-Users from Remote Sensing Analysis (OPERA) Project: Status, Access, Applications, Tools, and More
Authors: Handwerger Alexander L. , Chan Steven , Bekaert David ,   OPERA Team
Published: March 2024

Remote sensing satellites provide key data that can be used to better understand the Earth, respond to hazardous events, and to make decisions related to climate change, population growth, and more. For decades, many space agencies have provided high quality remote sensing data free of charge for their end-users. Although these data have been accessible, and widely used, the raw remote sensing measurements can be challenging to analyze for non-specialists. Furthermore, the large quantity of data available today makes it nearly impossible to perform large scale analysis on personal computers. To overcome these barriers, the Observational Products for End-Users from Remote Sensing Analysis (OPERA) project, led by the Jet Propulsion Laboratory, with project partners from NASA, USGS, and academia, are producing three analysis ready data products derived from satellite-based synthetic aperture radar (SAR) and optical data. These products were designed to meet the needs of U.S. federal agencies that were identified by the Satellite Needs Working Group (an initiative of the U.S. Group on Earth Observations). The OPERA analysis ready data products are derived from the NASA/USGS Landsat 8/9 sensors, ESA’s Sentinel-1 and -2, and NASA-ISRO SAR Mission (NISAR). Specific products include: (1) a near-global Dynamic Surface Water eXtent (DSWx) product suite from optical and SAR data, (2) a near-global Surface Disturbance (DIST) product suite from optical and SAR data, and (3) a North America Displacement (DISP) product suite from SAR data. In addition, OPERA is producing intermediate-level products including: (1) a North America Land Coregistered Single-Look Complex (CSLC) product from SAR data, and (2) a near-global land surface Radiometric Terrain Corrected (RTC) SAR backscatter product from SAR data. These two intermediate SAR products allow for user-customized product generation. All OPERA products are freely available and all OPERA software are open-access (https://github.com/opera-adt). More information on OPERA can be found at https://www.jpl.nasa.gov/go/opera. Here, we present the latest OPERA project updates. We provide an overview of OPERA’s in-production products, which include DSWx, DIST, RTC, and CSLC, and information about OPERA’s future DISP product. We will showcase product use-cases, with a focus on detection and monitoring of hazards such as floods, wildfires, earthquakes, and landslides. We also discuss how the free and open OPERA data can be accessed through the NASA Distributed Active Archive Centers. Finally, we demonstrate our open OPERA application tools (https://github.com/OPERA-Cal-Val/OPERA_Applications) that are designed to increase data use and discoverability.
The Response of Geomagnetic Daily Variation and Ionospheric Currents to the Annular Solar Eclipse on 21 June 202
Authors: Liu Xiaocan , Chen Junjie , Han Peng , Lei Jiuhou
Published: March 2024

According to the ampere's law, the geomagnetic variations caused by the ionosphere current can detect the ionosphere electrodynamic process during a solar eclipse. Due to the lack of observation, the previous research on the geomagnetic effect of solar eclipse focused on the range of one or several geomagnetic stations, which makes the latitude and local variation characteristics of the geomagnetic effect and the corresponding ionosphere electrodynamics process are not totally studied. The annular solar eclipse on June 21,2020 passed through China during the daytime, and the regional high density observation of the Geomagnetic Network Center of China, Institute of Geophysics, China Earthquake Administration and International Real-time Magnetic Observatory Network provides a good opportunity for the study of this issue.
In this work, we studied the latitude and local time dependences of the geomagnetic-solar eclipse effect of the June 21,2020 annular eclipse event in China and the neighbour areas, and analyzed the electrodynamics process of the ionosphere. The results are as follows:

The eclipse weakens the intensity of three components for the geomagnetic daily variations. Among them, the effect of the north-south component ΔX has a clear latitude dependence, that is, the decrease of intensity significantly below the center of the Sq current vortex and is slightly weaker above the focus, while the eclipse effect of ΔX near the center of the current vortex is almost absent. In addition, the effect of the east-west component ΔY increases as latitude decreases and the eclipse obscuration rate increases .
The eclipse effect of ΔY along the totality from noon to afternoon shows a local time dependent, while the eclipse effect of ΔX component is not so regular like ΔY, it is roughly stronger from early afternoon to early afternoon than that in the late afternoon. The eclipse effect of the vertical component ΔZ was weak, mainly in the early afternoon period on the totality path.
The eclipse effects of the geomagnetic daily variation simulated by the TIEGCM are generally consistentwith those by the ground magnetometer data. It was demonstrated that the ionospheric current system caused by the eclipse has a counter-Sq pattern and thus weakens the background Sq current system.

 
Keywords: Geomagnetic Daily Variation, Ionospheric Currents, Solar Eclipse
Climate Change Studies through SWOT Phenomenology Research
Authors: Fayne Jessica
Published: March 2024

Climate change is driving extreme spatial and temporal variability in surface water resources. This is particularly important for lake and wetland features, which have been under-characterized on the global scale. This under-characterization is largely due to the complex structural properties of these surfaces relative to available remote sensing data.  
The Surface Water and Ocean Topography Mission, as the first-of-its-kind 2D mapping and satellite interferometer using Ka-band SAR, was developed for mapping water surface extents and water surface elevations, providing a significant improvement in how we characterize and monitor surface water. Because of the novelty of the Ka-band SAR data for surface mapping, there have been limited studies of additional utilities SWOT can provide to complement water surface extent and elevation observations.  
First-look images from SWOT over Toulouse, France and Long Island, New York, USA, revealed strong signal returns over non-water surfaces, including agricultural fields and urban regions. Subsequent images highlighted by the SWOT Science Team also demonstrated wind-driven water surface signal variability, akin to NASA-JPL airborne AirSWOT investigations.  
This project provides early assessments of SWOT phenomenology for estimating characteristics that could contribute to novel datasets, such as wind speed, wind direction (for long wave formations), vegetation moisture, vegetation structure, and land surface moisture fraction. This work provides the foundation for a multi-year study to further develop the Ka-band Phenomenology Scattering Model (KaPS), and the wind model Ka-SWOT Model (Ka-SMOD), and will additionally discuss necessary reference datasets, models, and in-situ sampling necessary to complete this these assessments.
This project will increase the utility of the SWOT mission for studying diverse water and land features and significantly improve our understanding of fine-scale terrestrial hydrology. Given the relatively short temporal availability of the preliminary SWOT data, this work will focus on spatial variability across global sites, within the fast-sampling orbit, for observations taken for available dates in 2023. This preliminary analysis of the spatial and temporal variability of SWOT-derived phenomena aims to demonstrate how SWOT can be used in novel ways to study climate change. 
Can in-field NIR spectroscopy provide an option for soil carbon monitoring?
Authors: Underwood Jessica , Keith Aidan , Leggatt Alister , Collins Christopher
Published: March 2024

Current soil sampling methods are expensive, time consuming and destructive. These constraints result in a standard practice that combines samples from a W transect across a field, into one composite sample for laboratory analysis. This presents a challenge for farmers, policy makers and industry, as this method of sampling doesn’t give the required detail about the variability of soil properties across the field. The heterogenous nature of soil means that differences between monitoring results across years could be due to changes in sample location, and the natural variability of the soil. This is of particular concern for farmers and policy makers monitoring soil carbon under the transition to sustainable farming methods, as they want to be sure that the change they see is due to management changes, not inherent variability.Simple, handheld, near-infrared (NIR) spectroscopy devices can be used in the field by practitioners. They are cheap, quick and non destructive. This allows for more samples to be taken across a field, and GPS allows repeat sampling of the same location over time. This paper looks at how accurate in-field soil spectroscopy performs compared to laboratory results, how variable soil properties are across a field, and how different sampling methods (W transect, random sampling) capture that variability.
Assessing Blue Carbon Storage in an Urbanized Coastal Region: Insights from Hong Kong's Seagrass Ecosystems
Authors: Zhao Man , Gaitán-Espitia Juan Diego
Published: March 2024

Seagrass meadows are globally important blue carbon sinks, accumulating organic carbon within their beds from both seagrass and the burial of non-seagrass organic matter.  To date, substantial attention has been attracted on this nature-based carbon offsetting solution, especially for countries with large blue carbon resources (e.g., Australia, Indonesia, and USA). However, the carbon sink potential of small coastal regions characterized by high carbon densities of blue carbon ecosystems and its contribution to regional climate change mitigation efforts remain largely unclear. This study focusses on the quantification of seagrass carbon stock in an urbanized coastal area, Hong Kong. We collect 1-meter sediment cores from four sites (i.e., San Tau, Yam O, Sheung Pak Nai and Ha Pak Nai) covering two seagrass species (i.e., Halophila beccarii and Halophila ovalis). Our investigation encompasses the analysis of total organic carbon (OC%), organic carbon sources (δ13C and δ15N), labile and recalcitrant organic carbon pools, and organic carbon accumulation rates (Pb210) at various depths within the sediment cores. The results of this study will shed light on the extent to which seagrass ecosystems can contribute to Hong Kong's Nationally Determined Contributions, as assessed under the IPCC Tier-II framework.
A Lagrangian Perspective of Coastally Trapped Kelvin Waves
Authors: Deogharia Rahul , Gupta Hitesh , Sil Sourav
Published: March 2024

The Bay of Bengal (BoB) annually experiences four phases of Coastally Trapped Kelvin Waves (CTKWs), namely, the first upwelling (January–March), first downwelling (April–June), second upwelling (July–September), and second downwelling (October–December). The upwelling and downwelling CTKWs are associated with propagating patches of negative and positive Sea-Surface Height Anomaly (SSHA) respectively. The second downwelling CTKW is the strongest and travel farthest . Given that the CTKWs are known to be confined near the coast, their behavior can also be effectively understood using the hyperbolic Lagrangian Coherent Structures (hLCSs) approach, wherein such structures act as barriers to material advection. The hLCSs are a set of material surfaces with pointwise maximal (minimal) repulsion and are referred to a repelling (attracting) hLCSs. 
In this study, we have computed the repelling hLCSs from the climatological (1993–2020) geostrophic currents derived from Archiving, Validation and Interpretation of Oceanographic (AVISO) altimetry data. These hLCSs were found to show close correspondence with the climatological SSHA signatures of the different phases of the CTKWs in the BoB. An even better correspondence was seen between these repelling hLCSs and the gradient of climatological SSHA fields. Moreover, these repelling hLCS were found to be located almost at a distance of Rossby Radius of Deformation (Rd) away from the coast. 
The hLCSs associated with the CTKWs have major implications on the advection patterns of passive tracer fields such as sea surface temperature, sea surface salinity, and chlorophyll-a. Since, these hLCSs act as material barriers, they were found to separate water masses with different thermodynamic and biological properties on either side of the hLCs. This can potentially result in distinct coastal circulations and biological productivity near the coast.
Simulation and Analysis of Disastrous earthquakes in the plains of SW Taiwan
Authors: Wen Strong , Yeh Yulien , Tu Kuan-Ting
Published: March 2024

There are many types of natural disasters in the world, among which earthquakes are sudden and highly uncertain, which may cause direct or indirect disasters, resulting in casualties, property losses, and infrastructure damage. Local seismic hazard analysis has been studied for a long time. This study uses historical earthquake data and virtual earthquake sources to simulate the propagation of seismic waves in urban areas in SW Taiwan. However, due to the limited number of existing free-field seismic stations and insufficient installation density, the accuracy of earthquake damage assessment is directly affected. Past research has pointed out that the use of scenario earthquake simulation can effectively simulate ground motions in local areas. Therefore, the goal of this study is to use numerical methods to construct a 3D seismic wave simulation, using numerical data and virtual seismic observation stations to simulate regional scales. However, due to limitations in computing resources and underground structure information, seismic waves calculated by 3D seismic wave propagation simulations can only cover relatively low-frequency (1 Hz) to calculate the vibration process and seismic resistance of the structure. Therefore, the goal of this study is to calculate low-frequency and high-frequency seismic waves separately, and to obtain broadband seismic waves containing low-frequency and high-frequency information through a hybrid method. The findings could be applied to future earthquake risk and building damage assessments.
Impact of near-surface hydraulic gradient on the interrillerosion process
Authors: Wang Yujie , Wang Bin , Wang Chenfeng , Wang Yunqi
Published: March 2024

The impact of near-surface hydraulic gradients on interrill erosion is still obscure. The objective of this study is to distinguish the dominant interrill erosion process in areas impacted by near-surface hydraulic gradients. A series of rainfall simulations were conducted on a clay loam soil subjected to near-surface hydraulic gradients that shifted from drainage/saturation conditions to seepage conditions under three rainfall intensities (30, 60 and 90 mm hr−1) and two slope gradients (5 and 10). The results showed significant differences in soil loss between all the treatments. The sediment concentrations for seepage conditions were 0.57 to 7.02 times greater than those for drainage conditions. The correlation analysis indicated that the near-surface hydraulic gradient was a governing factor affecting interrill erosion. The critical flow rate was larger than 90 mm hr−1, suggesting that thin sheet flow does not have sufficient power to detach soil particles without raindrop impact. Furthermore, the detachment rates by raindrop impact were 1.12 to 4.60 times greater for seepage conditions than for drainage conditions. As the near-surface hydraulic gradient shifted from drainage conditions to seepage conditions, it transitioned from transport-limited to detachment-limited, and the contribution of interrill erosion to overall erosion increased from 20.19 to 75.30%. The critical point of dominant interrill erosion process transition existed between saturation (SA) and artesian seepage in 20 cm of hydrostatic pressure head (SP20). The results emphasize the importance of the near-surface hydraulic gradients’ impact on the interrill erosion process. Further investigations need to be verified in different soil types, steeper slopes and natural storms.
Modeling simulation of aerosol light absorption: the impact of mixing state and aging process
Authors: Du Huiyun , Li Jie , Chen Xueshun
Published: March 2024

Black carbon has an important effect on global climate change. Uncertainty surrounding the absorption property of BC-containing aerosols still exists. In this study, the optical property of PM2.5 in Beijing in November 2018 was investigated using Mie theory based on observed and simulated PM2.5. The results showed that the  absorption coefficient under uniform internal mixing is the highest, followed by core-shell mixing and calculation for external mixing is the lowest. The calculated BC absorption at 630 nm under a mixed mixing state (fraction of internal mixing constraint by observation) was reasonably close to the measured mean value. The simulations of the NAQPMS reproduced the temporal distribution of PM2.5 and its components in Beijing well. Under the same mixing state, the absorption coefficient can be highly impacted by the simulation of PM2.5 components. The aging process of BC can be reproduced by advanced microphysical module (APM) in NAQPMS. Then the fraction of aged BC can be used as a proxy for internal mixing proportion, and the absorption coefficient was reasonably reproduced. This study will provide a reference for the three-dimensional model simulation of black carbon aerosol radiation effect.
Mid-Holocene relative sea-level reconstruction from digital surface models of coral microatolls at Pulau Semakau, southwestern Singapore 
Authors: Aung Lin Thu , Tan Nural Syafiqah , Quye-Sawyer Jennifer Susan , Tab Fangyi , Komori Junki , Aw Zihan , Yeo Jing Ying , Neo Wan Lin , Baltz Maya , Maltzner Aron
Published: March 2024

Coral microatolls are coral colonies that grow with distinct morphologies consisting of living polyps on their outer perimeters and dead upper surfaces with concentric rings in planform. Their upward growth is limited by the lowest tides, allowing them to be used as precise indicators of relative sea-level (RSL) change. Therefore, detailed morphological investigation of fossil microatolls provides an important proxy for the reconstruction of past RSL. We present a preliminary RSL reconstruction from Pulau Semakau (Semakau Island), southwestern Singapore, based on digital surface models (DSMs) of fossil corals captured by portable iPhone LiDAR integrated with field survey data and radiocarbon analysis. Pulau Semakau is the largest field site in Singapore, with an intertidal flat extending more than 2 km long by 0.4 km wide, on which we observed 79 living and 65 fossil microatolls containing well preserved, concentric rings. In this study, we reconstruct mid-Holocene RSL using seven fossil, Diploastrea heliopora microatolls, relative to living counterparts on the island. DSMs indicate that three of these fossil corals are lower in elevation at the center with higher outer rings, indicating gradual RSL rise between ~7700 and 7500 cal yr BP. Conversely, three fossil corals are observed to decrease in elevation from the innermost to outermost rings, indicative of RSL fall between ~7350 and 7200 cal yr BP. These observations are consistent with but more well constrained than the existing sea-level curve of Singapore based on sea-level index points (SLIPs) and limiting dates from intertidal mangrove and shallow marine sediments. RSL records between ~7500 and 7350 cal yr BP are largely uncertain due to erosion of a fossil coral, and this remains as future work. The initial results reflect mid-Holocene RSL fluctuations at Pulau Semakau, from ~7700 to 7200 cal yr BP.
Palaeoseismology and tectonic geomorphology for detecting the seismic behaviour of the Pidima-Anthia Fault, south Greece
Authors: Koukouvelas Ioannis , Ganas Athanassios , Zygouri Vasiliki , Tsimi Christina
Published: March 2024

Geomorphologic analysis and data from paleoseismological sites across segmented active faults help the evaluation of past and future seismic faulting. The study of paleo-earthquakes on the Pidima-Anthia Fault provides an opportunity to unravel the seismic behaviour of the Eastern Messinia Fault Zone (EMFZ) that defines the western border of the N-S trending Taygetos Mtn range in Peloponnese (southern Greece). This fault zone is segmented and includes a complex system of primarily normal fault- segments dipping westwards, with a traceable length from 6-10 km. We applied geomorphological and palaeoseismological analysis across the Pidima-Anthia Fault segment. The palaeoseismological trench data provide evidence for five M >6.4 earthquakes and indicate an apparent slip rate of 0.23 mm/a. Geomorphologically, the modelling of a footwall series of triangular facets, attest to a slip-rate estimation in the order of 0.28-0.44 mm/a. These data highlight that the slip rate of the fault is remarkably stable for the Quaternary period but particularly over the last 17 ka period, as well as that this duration is enough for a morphogenic active fault to create seismic landscapes. The Holocene earthquake history of the Pidima-Anthia Fault allows its comparison with six other known active normal faults of southern Greece. The overall data indicate a pattern of earthquake clustering in the southern Greece faults ("Wallace-type" behaviour). In particular, the Pidima-Anthia Fault's seismic history resembles with time predictable earthquakes and clustering during the Holocene. However, the Pidima-Anthia Fault during the current period (i.e., post 1 Ka AD) does not display cluster time-predictable behaviour, and a strong earthquake can happen at any time.
Farming digital data: Even when the cows come home
Authors: Triantafilis John , Van Zadelhoff Feiko , Ardo James , Edwards Peter , Kumar Kishor , Jagath Ekanayake , McNally Sam
Published: March 2024

Increasingly, multinational brands, manufacturers, and retail customers want to demonstrate where individual components of their supply chain have come from, and they have been made sustainably using a triple-bottom-line approach (i.e., social well-being, environmental health, and a just economy). One example is the need for farmers to demonstrate they are transforming their operations into climate-smart landscapes, decarbonising their operations (i.e., minimising inputs) and supply chains to contribute to global net zero, while at the same time being financially sustainable. Others include reduction in inputs including but not limited to precision application of fertilisers (e.g., nitrogen and phosphorus), ameliorants to overcome soil acidity (e.g., lime) and water for irrigation. In the first instance, this requires information on various soil ‘conditions’ including the ‘capacity’ of soil to be improved in terms of its soil ‘capability’. In this presentation we demonstrate how we develop digital soil maps (DSM) of soil ‘capacity’ including but not limited to i) physical (mineral surface area [MSA]), ii) biological (carbon [C] and nitrogen [N]), iii) chemical (cation exchange capacity [CEC], and P-sorption [P]), and iv) hydrological (permanent wilting point [PWP], field capacity [FC], plant available water [PAW]), on the Lincoln University Dairy Farm. In this regard, the DSM are developed using digital data collected using either remote (i.e., LiDAR) or proximal sensed (i.e., gamma-ray spectrometry and electromagnetic (EM) induction) data. In this presentation, we show how the individual DSM are stored online (ArcGIS web app) and the rationale for ‘Farming digital data’ described (ArcGIS Story Map). The final DSMs are described in terms of how knowledge of the heterogeneity of different soil ‘capacity’ enables a farmer to understand how the ‘capability’ of soil can be improved, respectively, and in terms of; i) where best to invest in soil organic carbon sequestration initiatives (MSA), ii) how to monitor carbon dioxide/nitrous oxide emissions and microbial population (C:N ratio), iii) more precisely apply fertilisers (e.g., N and P) and ameliorants (e.g., lime and gypsum), and iv) improve water use efficiency with variable rate irrigation (PAW). Brief insights into how these DSMs underpin the development of a Digital Agriculture framework are also presented ‘Even when the cows come home’.
Characteristics of PM2.5 distribution and its Hot Spot using Scanning LiDAR 
Authors: Lee Gahye , Lee Dasom , Kim Seongmin , Park jeong-min , Kim Kwanchul , Kim Sangcheol , Jung Youndae , Yang Ilkwon
Published: March 2024

Over recent decades, air quality has become major concern over the Korean peninsula. Because of the growing concern, the Korean government regulated air pollutants management policies and developed the technologies for improving air quality. Thus, the long-term trends of PM10 emissions are gradually decreased. However, industrial complexes including various industries are concentrated and distributed with insufficient prevention management for air pollutant emission facilities. In addition, these facilities are emitted high concentrations of PM2.5 and the emissions are dispersed nearby residential areas, which can have a direct adverse effect on the environment and health. Therefore, it is judged that efficient management of the emission of air pollutants in industrial complex areas is necessary. So this study to identify major and illegal emission sources in industrial complexes and propose management measures.In this study, we investigated that the characteristics of the concentration of PM2.5 from the industrial complex in Siheung-si, Gyeonggi-do are using Scanning LiDAR for analyzing spatiotemporal distribution and identifing Hot Spots. We were analyzed hourly, daily, and monthly average of PM10 and PM2.5 concentrations based on scanning LiDAR measurement datasets. Distributions of Hot Spots in PM2.5 were selected and visualized using the GIS Heat map technique. The result showed that the concentration of hourly averaged PM2.5 gradually increased from 08:00 to work. And from 09:00 to 13:00, the high concentration phenomenon appeared. And the concentration increased again from 15 to 17:00, and then the concentration gradually decreased from 18:00. Heat map showed that a total of 7 Hot Spots from A to G were identified within the Scanning LiDAR observation area. Moreover, it was found that high-concentration of PM2.5 was emitted in the three areas of E, F, and G. The three main emission sources were classified into manufacturing industries such as food manufacturing and metal steel factory. Therefore, it can be used as basic data for efficient emission sources and hotspot management improving air quality.Acknowledgment: This research was supported by a grant (2023-MOIS-20024324) of Ministry-Cooperation R&D Program of Disaster-Safety funded by Ministry of Interior and Safety (MOIS, Korea) and Metropolitan Environment Management Office in Gyeonggi-do Province, Korea.
Projected changes in Compound Extremes under low to high emission SSPs Scenarios
Authors: Chaubey Pawan Kumar , Attada Raju
Published: March 2024

The compound extremes of rainfall and temperature increase globally under the warming climate. Over the past few decades, the frequency and intensity of compound extremes, such as extreme rainfall events and heat waves, have increased across various climatic zones in India. This study aims to analyze the changes in these compound extremes at specific thresholds (percentiles) from CMIP6-based Multi-Model Ensemble (MME). We further examine the future changes in extremes in different time frames, i.e., near (2015-2040), mid (2041-2070), and far (2071-2099) future at annual and seasonal time scales. The projected extremity under the new Shared Socioeconomic Pathways (SSPs) showed an increasing trend in consecutive dry (wet) stages over an increase in northern (central) parts of India. Intense and frequent heat waves are mainly concentrated over the north-central region under the low to high-emission scenarios. Also, India's northern, central, and western regions may experience more extremity under high-emission (SSP5-8.5) scenarios that highlight the importance of developing long-term adaptation and mitigation strategies aimed at reducing climate vulnerability.
Feasibility of Retrieving Lunar Near-Surface Dust Density Using Radio Occultation Measurements 
Authors: Oudrhiri Kamal , Yang Oscar , Erwin Daniel A. , Withers Paul , Buccino Dustin R.
Published: March 2024

Lunar charged-dust dynamics (levitation and transportation) could be one of the primary sources to dominate the near-surface plasma environment on the Moon. Charged dust grains could reached up to a few kilometers above the moon surfaces and forming a complex dusty plasma environment. The findings of NASA’s LADEE Lunar Dust Experiment confirms the dust density variations at different altitudes above the surface. Additionally, previous research has reported the detection of the Moon’s electron density profiles using radio occultation measurements; these radio signals were made from Lunar missions, including Chandrayaan, Luna-19, Luna-22, LRO, GRAIL, and SELENE, providing accurate phase measurements with Allan deviations between 10-12 – 10-13. In this research, we will present a feasibility assessment of using the lunar radio occultation measurements to estimate the near-surface dust concentrations. Understanding the nature of near-surface dust density and dynamics is essential to assessing the dusty plasma environment impacts on future human and lander missions on the Moon.
Anomalous Seawater Radiocarbon Depletion Event during Glacial Interval in the Equatorial Indian Ocean Thermocline
Authors: Jena Sanjit Kumar , Bhushan Ravi , Jena Partha Sarathi , Bharti Nisha , Athiyarath Krishnan Sudheer , Shivam Ajay , Dabhi Ankur
Published: March 2024

The role of intermediate water mass in ocean circulation is well acknowledged from the global oceanographic and climatic perspectives. Abnormal depletions in the upper oceanic radiocarbon concentrations during the last deglaciation have been attributed to the southern ocean sourced aged CO2 ventilations via Antarctic intermediate waters. However, the fundamental origin and nature of the source, and its spatio-temporal variability still remains a question.The present study reconstructs the radiocarbon records of the upper Equatorial Indian Ocean (EIO) over the last 44 ka using the radiocarbon dating of depth-specific planktonic foraminifers. The results reveal an extremely depleted radiocarbon interval in the EIO thermocline between 25-34 ka during the Marine Isotopic Stage 3 – Marine Isotopic Stage 2 (MIS3-MIS2) transition. The Reunion hotspot and/or the Amsterdam Island appear to be the responsible source(s) of contemporaneous hydrothermal dead carbon supply into the EIO thermocline. However, the deglacial thermocline radiocarbon depletions were primarily caused by the southern ocean sourced aged CO2 ventilations only. The radiocarbon records also indicate a well stratified upper oceanic condition prevailing over the EIO during the last 44 ka.
Heat, humidity and health impacts: How causal diagrams can help tell the complex story
Authors: Sivaraj Sidharth , Buzan Jonathan , Romppainen-Martius Olivia , Vicedo-Cabrera Ana M.
Published: March 2024

The global health burden associated with exposure to heat is a grave concern and is projected to further increase under global warming. While physiological studies have demonstrated the role of humidity alongside temperature in exacerbating heat stress for humans, epidemiological findings remain conflicted to date. Understanding the intricate relationships between heat, humidity, and health outcomes are crucial for future adaptation and mitigation. This project introduces 'directed acyclic graphs' (DAGs) as causal models to elucidate the analytical complexity in observational epidemiological studies focusing on humid heat related health impacts. DAGs are employed to delineate implicit assumptions often overlooked in such studies, depicting humidity as a confounder, a mediator, or an effect modifier. The complexities arising from using composite heat-stress indices such as wet-bulb temperature, emphasizing the limitations induced in extracting individual effects of humidity are also portrayed through DAGs. Theoretical generalisations for regression models corresponding to each of the causal assumptions are also discussed. The goal of the study is not to prioritize one causal model, but to explicitly discuss the potential causal models suitable for representing associations between heat, humidity, and related health impacts. In the process, we highlight the implications of selecting one model over another. The project aims to inspire further quantitative studies on the topic and motivate researchers to explicitly characterize the assumptions underlying the analytical models with DAGs, facilitating accurate interpretations of the findings. This extends beyond analysing the role of humidity in heat-related health impacts, encompassing similarly complex research questions associated with other compound events.