bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Long-term Trends in Asian Aerosol Optical Depth Using Ground-based Observational Data
Authors: Chai Yujin , Kim Jhoon , Cho Yeseul
Published: March 2024

Aerosols play a crucial role in affecting air quality, climate change, and public health. They show significant differences in concentration across regions and fluctuate over time. Therefore, it's essential to examine long-term changes in aerosol levels and analyze the associated patterns to improve air quality and advance climate change research. This study specifically looks at the long-term trends of Aerosol Optical Depths (AODs) in Asia and compares the trends of Fine-mode Aerosol Optical Depths (FAODs) and Coarse-mode Aerosol Optical Depths (CAODs). AOD indicates how much solar radiation is blocked by aerosols in the atmosphere, serving as an important measure of aerosol quantity. The Aerosol Robotic Network (AERONET) is a ground-based observation network providing detailed information on aerosol properties globally. AERONET has extensive long-term data and ensures continuous observations through daily measurements. Consequently, we analyzed the prolonged trends of AOD using AERONET data. To understand changes in aerosol quantity from human-made sources and natural events like yellow dust, we examined trends in Coarse-mode Aerosol Optical Depths (CAODs) and Fine-mode Aerosol Optical Depths (FAODs), categorizing aerosols by size. By comparing CAODs and FAODs, we identified consistent trends in the analysis across countries or sub-regions. This analysis highlights significant regional differences in aerosol concentrations, influenced by factors such as the local environment and air quality policies of each country.
Monitoring river morphology with Sentinel 2 data: limitations and opportunities across scales 
Authors: Bozzolan Elisa , Bizzi Simone , Brenna Andrea , Surian Nicola , Carbonneau Patrice
Published: March 2024

Satellite imageries are starting to become for geomorphologists a new tool to monitor medium-large river dynamics at high revisit time (weekly or daily). The Sentinel 2 mission, in particular, provides without charges a multi-spectral image of the earth surface at 10 meters resolution every 5 days (cloud cover permitting). Machine learning algorithms can then classify these images, automatically discriminating those river macro-geomorphic features, i.e. water, sediment and vegetation, that describe how a river responds to different hydrological impulses and boundary conditions. When using these tools (Sentinel 2 images + machine learning algorithm), it is important to first identify what geomorphic processes we can reliably detect, i.e. what are the applicability boundaries dictated by the spatio-temporal resolution of these images. In a dynamic, braided reach of the Sesia River (Northern Italy), we assessed how this inherent uncertainty associated with S2's spatiotemporal resolution can impact the interpretation of the active channel (a combination of sediment and water) delineation and evolutionary trajectory. The analysis demonstrates that water is ∼20% underestimated whereas sediments are ∼30% overestimated. These under- and over-underestimations are not random but a function of the mixed pixels present in each classified macro geomorphic unit. Nevertheless, the results show that these spatial errors are an order of magnitude smaller than the geomorphic changes detected in the 5 years analysed, so the derived active channel trajectory can be considered robust. Within these newly assessed applicability boundaries, in the Po River basin we started to explore in similarly dynamic river reaches new geomorphic indicators able to describe river responsiveness to seasonality and to different flood regimes.
3D modelling of internal tide generation
Authors: Le Dizes Cécile , Mercier Matthieu , Grisouard Nicolas , Thual Olivier
Published: March 2024

Internal tides, generated by the interaction of tidal flows with underwater topographies, play a pivotal role in ocean dynamics. They significantly contribute to energy transport in the oceans and can lead to deep-ocean mixing, influencing large-scale ocean circulation and ecosystems through nutrient transport. Their accurate representation in large-scale numerical models is essential to improve our understanding of oceanic processes and assess their impact on climate scenarios. However, implementing internal tide generation is challenging due to the variety of spatial and temporal scales involved. It cannot be tackled by estimations from observations and/or numerically expensive regional models alone. In this context, analytical methods offer insights to accurately describe the internal tide wavefield, enabling more precise parameterizations in global ocean models. Existing analytical approaches are based on specific (limiting) assumptions, often considering two-dimensional situations or weak amplitude topographies.Here, we present a boundary element method to compute the internal tide radiated for a prescribed barotropic tidal flow over any arbitrary localized three-dimensional topography. This method, based on a Green's functions approach, assumes linear Boussinesq generation for harmonic tidal forcing (hence with a weak-amplitude excursion) and uses vertical mode decomposition to express the wave velocity field and the energy flux of the internal waves radiated in all directions. The properties of the internal tide generated by an axisymmetric Gaussian topography for constant stratification are discussed in detail. Results for the sub-critical regime (internal wave slopes larger than the topography) are consistent with the Weak Topography Approximation in the limit of small seamounts and when the influence of the Coriolis frequency is negligible. A specific discussion is made regarding the influence of the Coriolis frequency on the direction of emission for the internal tide radiated by axisymmetric seamounts. An important result is that the direction where the internal tide flux is maximum is controlled by the relative importance of the Coriolis frequency with respect to the tidal frequency, the orientation of the tidal flow, and the geometrical properties of the topography. Interestingly, for topographies elongated in one specific direction, the role of the Coriolis effect becomes negligible; the orientation of the tidal forcing and the one associated with the topography alone control the angular dependency of the energy flux radiated.Our work is a first approach to realistic analytical modeling of internal tide generation. It emphasizes the importance of considering the 3D effects for this problem.
The Influence of Stratospheric Hydration from the Hunga Eruption on Chemical Processing in the Stratospheric Winter Polar Vortices
Authors: Santee Michelle , Manney Gloria , Lambert Alyn , Millan Luis , Livesey Nathaniel , Pitts Michael , Froidevaux Lucien , Read William
Published: March 2024

The January 2022 eruption of the undersea Hunga volcano injected an unprecedented amount of water vapor directly into the stratosphere. In this talk, we will use measurements of gas-phase constituents from Aura MLS (Microwave Limb Sounder) and polar stratospheric clouds (PSCs) from CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) on CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) together with meteorological reanalyses to investigate how the extraordinary stratospheric hydration and accompanying anomalies in stratospheric temperature and circulation from Hunga affected chemical processing and ozone destruction in the polar lower stratosphere. We will focus on the Antarctic ozone hole season of 2023, when the excess moisture led to unusually early and vertically extensive PSC activity and heterogeneous chlorine activation (i.e., depleted HCl and enhanced ClO) in early winter. Although unmatched in the satellite record, the early-winter upper-level chlorine activation was insufficient to induce substantial ozone loss. Chlorine activation, denitrification, and dehydration processes saturated in midwinter, with trace gas evolution essentially following the climatological mean thereafter. Thus, despite the exceptional early-winter conditions, cumulative ozone losses in the 2023 austral spring were mostly unremarkable because stratospheric chemical processing saturated, as typically happens in the Antarctic. We will also discuss the 2022 Antarctic winter, when the Hunga plume was effectively excluded from the southern polar region by the strong transport barrier at the edge of the vortex. As a result, Hunga had little effect on either the vortex itself or the chemical processing and ozone loss that took place within it during the 2022 Antarctic winter/spring. Finally, we will touch briefly on the influence of Hunga on the 2023/2024 Arctic winter that will have just concluded.
Tree canopy characteristics influence human heat stress reduction: comparative case study for two sites in different climates
Authors: Lee Hyunjung , Park Sookuk , Mayer Helmut , Kim Jinkeun
Published: March 2024

Increasing tree canopies is one of the effective measures to reduce heat at different spatial scales in cities. From a human-biometeorological perspective, tree canopies cool the trunk space below by reducing solar radiation, thus providing shade and lowering the net radiation overall. They also reduce the air temperature above them through transpiration, but this process also increases the water vapor pressure, which slightly counteracts a lowering of human heat stress. However, these two effects mainly affect the layer above the tree canopies. Therefore, they are less likely to promote the lowering of outdoor human heat stress at the pedestrian level below the tree canopies.As a valuable benefit for the enhancing of human thermal comfort in urban areas, the cooling potential of tree canopies depends on their dimension, shape and leaf density. Even if trees have comparable physical states, they may influence the micrometeorological variables that control local human thermal comfort differently in various climate zones. In this context, the study shows the human-biometeorologically significant cooling potential of street trees at two exemplary selected urban sites in different climate zones. According to the Köppen and Geiger climate classification, the Jeju site (N 33˚ 49'00'', E 126˚ 50'00''), Republic of Korea, is in the Cfa climate zone, whereas the Stuttgart site (N 48˚ 46'38'', E 9˚ 10'30''), Germany, is in the Cfb climate zone.Based on the validated version of the ENVI-met v5.0.2 software, systematic simulations were conducted on typical summer days to show the effect of various tree canopy characteristics, which refer to two tree dimensions, two values of the leaf area index (LAI), and three shapes of tree crowns (ellipsoid, triangle, and inversed triangle), on the level of outdoor human thermal comfort at both sites.In the simulation results for sunny conditions, it is noticeable that tree canopies in the shape of ellipsoids exhibit the highest reduction in mean radiant temperature (Tmrt), which is considered a key factor in human thermal comfort. In Jeju it varies between 6 and 25 K and in Stuttgart between 11 and 27 K. The remarkable reduction of Tmrt leads to a maximum cooling potential of the physiological equivalent temperature (PET), as quantitative measure for human thermal comfort, of 12 K in Jeju and 14 K in Stuttgart. Assuming that the PET classification applies to both climate zones, the result is that the level of PET classification at both locations in different climate zones decreases from “very hot” to “warm”. This research forms the basis for complementary studies on the human-biometeorologically significant cooling effect of tree canopies with various characteristics that extend to other different climate zones.
Ozone deposition measurements over wheat fields in the North China Plain
Authors: Zhang Xiaoyi , Xu Wanyun , Lin Weili , Zhang Gen , Geng Jinjian , Zhou Li , Zhao Huarong , Zhou Guangsheng , Xu Xiaobin
Published: March 2024

Ozone (O3) deposition contributes 20% to the annual global tropospheric O3 loss, affecting surface air quality,, the ecosystem and climate change. Limited by the instrument and method shortage, O3 deposition in China, experiencing significantly increasing O3 exposure, was less observed and investigated. Here, we conducted a comprehensive measurement of O3 deposition over the wheat canopy at a typical polluted agricultural site of North China Plain using a new relaxed eddy accumulation (REA-O3 flux) system. O3 deposition flux and velocity (Vd) were at the averages of -0.25±0.39 μg m-2 s-1 and 0.29±0.33 cm s-1, respectively. Daytime Vd (0.40±0.38 cm s-1) was obviously higher than in the nighttime (0.17±0.26 cm s-1). Vd played a decisive effect on the diel pattern of deposition flux, while O3 concentration determined the flux variability on the longer timescales. The temporal changes of Vd were mainly determined by crop growth during wheat growing season, with predominantly contribution of stomatal uptake. Both daytime and nighttime Vd exhibited significant increase with decreasing relative humidity, and increasing friction velocity and soil water content, enhanced by higher leaf area index. With rapid increase of soil moisture, simultaneous and following overall increments in Vd were detected, attributed that stomatal conductance increased and opening extended to the night, remarkably strengthening O3 stomatal uptake, and soil NO emission might be strengthened at moist condition, facilitating non-stomatal O3 removals at night. The study suggests the leading effects of crop growth on O3 deposition modulated by environmental condition and the non-negligible influences of nocturnal plant activities, and emphasizes the needs for O3 deposition observation over different surface and accurate evaluation of O3 agricultural impacts based on deposition fluxes.
Data-Driven Discovery of Fokker-Planck Equation for the Earth's Radiation Belts Electrons Using Physics-Informed Neural Networks
Authors: Camporeale Enrico
Published: March 2024

We use the framework of Physics-Informed Neural Network (PINN) to solve the inverse problem associated with the Fokker-Planck equation for radiation belts' electron transport, using 4 years of Van Allen Probes data. Traditionally, reduced models have employed a diffusion equation based on the quasilinear approximation. We show that the dynamics of “killer electrons” is described more accurately by a drift-diffusion equation, and that drift is as important as diffusion for nearly-equatorially trapped ∼1 MeV electrons in the inner part of the belt. Moreover, we present a recipe for gleaning physical insight from solving the ill-posed inverse problem of inferring model coefficients from data using PINNs. Furthermore, we derive a parameterization for the diffusion and drift coefficients as a function of L only, which is both simpler and more accurate than earlier models. Finally, we use the PINN technique to develop an automatic event identification method that allows identifying times at which the radial transport assumption is inadequate to describe all the physics of interest.
Analysis of convective storm characteristics to classify the storm severity information using weather radar variables
Authors: Kang Eunbi , Kwon Soohyun , Lee Seungwoo
Published: March 2024

  Recently, the increase in convective storms that develop rapidly within a short period of time and on a very small area causes severe damage to property and human life. Thus, it is important to understand the characteristics of convective activities and to provide the information about severity of the developing storms.  In order to address these issues, object-based analysis of convective systems is essential to provide severity information on convective precipitation systems including their life-cycle from initiation to dissipation.   In this study, we analyzed the developing stage of convective storms by using the statistics of storms detected by the Fuzzy Logic Algorithm for Storm Tracking (FAST). The Column Maximum (CMAX) was used to provide the information on detection and severity of storms. A convective storm was defined as a CMAX values above 35dBZ and small convective cells with an area less than 20km2 were filtered out. The identified storm was tracked on a fuzzy basis using storm speed and its morphological characteristics. Within the detected storm area, we analyzed the characteristics of the storm by averaging variables such as reflectivity (ZH), echo top height corresponding to ZH, rainfall rate at 1.5km altitude, VIL (Vertical Integrated Liquid) contents, etc.  This study aims to provide quantitative information on severity of individual storms by using these radar variables and storm characteristics. We calculated and modified the threshold values of each predictor for determining the severity of the convective storms. Furthermore, we plan to analyze the intensity and frequency of severe precipitation storms in associated with the occurrence or absence of lightning event during their life cycle.Key words : Weather Radar, convective storms, Radar parameter, storm severity※ This research was supported by the "Development of radar based severe weather monitoring technology (KMA2021-03121)" of "Development of integrated application technology for Korea weather radar" project funded by the Weather 
Observational energy transfers of a spiral cold filament within an anticyclonic eddy
Authors: Qiu Chunhua , Wang Dongxiao
Published: March 2024

The ocean surface mixed layer represents a critical interface linking the ocean and atmosphere. The physical processes determining the surface mixed layer properties and mediate atmosphere-ocean exchange. Submesoscale processes play a key role in cross-scale oceanic energy transformation and the determination of surface mixed-layer properties, including the enhancement of vertical nutrient transport, leading to increased primary productivity. Herein, we presented observations of the spiral chlorophyll-a filament and its influence on turbulence within an anticyclonic eddy in the western South China Sea during August 2021. The filament had a negative Ertel potential vorticity associated with strong upwelled/downward currents (approximately 20-40 m/day). Across-filament sections of the in-situ profiles showed turbulent dissipation rates enhanced in the filament. We suggested this enhancement values can be attributed to submesoscale processes, which accounted for 25% of the total parameterized turbulent dissipation rates. The present parametrized submesoscale turbulent scheme overestimated the in-situ values. The filament transferred kinetic energy upward to anticyclonic eddy via barotropic instability and gained energy from the anticyclonic eddy via baroclinic instability. After kinetic energy budget diagnostic, we suggested besides symmetric instability, centrifugal instability and mixed layer baroclinic instability should also be included in the turbulence scheme to overcome the overestimation. The observed dual energy transfers between the anticyclonic eddy and filament, and the observed high turbulent energy dissipation within the filament, emphasized the need for these processes to be accurately parameterized regional and climate models. 
The Early Silurian diabase dikes in the northern margin of the Yili Block, southwestern CAOB: insight into rift-related magmtism
Authors: Chen Youxin , Wang Meng , Zhu Shengqiang , Cao Ming
Published: March 2024

The Central Asian Orogenic Belt (CAOB) is one of the largest orogenic collages in the world, and preserves important records of accretionary orogeny and Phanerozoic continental growth. The Yili Block is one microcontinent in southwest of CAOB, with Precambrain basement rocks exposed in the northern and southern margin. The Middle to Late Ordovician arc-type magmatic rocks were identified in the northern margin of the Yili Block with a subduction-related calc-alkaline affinity conclude that the southward subduction of the Junggar Ocran beneath the Yili Block, but the Silurian magmatism is rarely reported.Mafic dikes preserve a considerable amount of geological information about geodynamics, crustal evolution and transformation of the regional stress field. Multi-period basic dikes, including Neoproterozoic and Carboniferous, are exposed in the northern margin of the Yili Block, which record important information about the transformation process of regional tectonic system. Recently, we have identified early Silurian diabase dikes in the Precambrian metamorphic rocks in the Wustu area, Wenquan County, northern margin of Yili Block. This paper reports zircon U-Pb age and Lu-Hf isotopic compositions, whole-rock geochemistry and Sr-Nd isotopic compositions for the Wustu diabase dikes and its surrounding rocks. One diabase sample yielded a zircon U-Pb age of 442±7 Ma with positive εHf(t) values (+3.0~+9.1), and its surrounding rock sample (leucogranite) yielded a zircon U-Pb age of 901±3 Ma. The diabase samples have high TFe2O3 contents (8.34%~9.81%) and K2O+Na2O contents (5.72%~6.86%), low MgO contents (3.69%~4.38%) and TiO2 contents (1.69%~2.00%) and belong to the high-K calc-alkaline series. The samples are enriched in the large ion lithophile elements (LILEs, such as Rb, Th, U and K) and have negative anomalies in the high-field-strength elements (HFSEs, e,g. Nb, Ta and Ti), with low Nb/Th ratios (0.13~1.16), Nb/La ratios (0.42~0.45) and high Zr/Hf ratios (39.6~42.2). They also have high initial 87Sr/86Sr ratios (0.707369~0.708637) and positive εNd(t) values (+1.9~+3.6). Our results indicate that they were sourced from a metasomatic sub-continental lithospheric mantle, which mainly composed of spinel iherzolite and garnet iherzolite. The trace element contents and its ratios, such as Zr (212×10-6~242×10-6), Hf (5.16×10-6~6.02×10-6), Nb (6.69×10-6~9.24×10-6), Ta (0.60×10-6~0.81×10-6), Zr/Y (5.21~6.82) and Hf/Th (0.69~0.91), indicate that the diabase dikes formed in an extensional setting during the early Silurian. Finally, we propose that the extensional tectonic setting maybe relate to the change of the subducted slabs angle or tectonic regime transition induced by the collage of the Aktau-Wenquan continental domain to the Yili Block in the end of Ordovician.
Asymmetries between phases of Atlantic Multi-decadal Variability in the CMIP6 multi models
Authors: Baek Haedo , Lee Dong Eun , Kim Yeong-Ho , Park Young-Gyu , Kim Hye-jI , Lee Eun Young
Published: March 2024

The Atlantic Multidecadal Variability (AMV) is a phenomenon in which North Atlantic Sea Surface Temperature Anomalies (SSTAs) occur almost simultaneously in the subpolar and tropical regions, imprinting their impact not only on neighboring countries but also on the global climate system.Due to its long lifespan, the natural variability associated with AMV seriously amplifies the uncertainty of future climate projections, as the exact mechanisms of the AMV remain unknown despite numerous previous studies.In this study, we investigate the asymmetry in two opposite phases of AMV in different models using preindustrial control experiments from 46 different models participating in the Coupled Model Intercomparison Project 6 (CMIP6). Overall, we find a well-fitted positive linear relationship for tropical Atlantic SSTAs with respect to subpolar SSTAs among 46 models. However, when investigating the model sensitivity between two opposite AMV phases in each model, we find that the strength and phase preference in terms of the tropical SSTA sensitivity to subpolar SSTA widely vary, resulting in AMV+ preferred groups, AMV- preferred groups, or symmetric AMV groups.Among the three groups, the characteristics of models in the AMV+ preferred group are found to be most distinctive. It is most notable with the AMV+ preferred models that the net surface heat flux in the subpolar Atlantic adds heat from the atmosphere into the ocean during the positive AMV phase due to a robust hemispheric reduction of the Westerlies and the Trades.In contrast, it is clearly indicated with the AMV+ preferred model during negative phases of AMV, or with all other model groups during both AMV phases, that subpolar SSTAs associated with AMV originate from the ocean, rather than the atmosphere.This contrast in subpolar A-O interaction found in the AMV+ preferred model can be partially explained as the result of competition between subpolar and tropical SST influences, involving surface ocean feedback in the Tropical Atlantic. As the AMV+ positive group shows a significantly larger weakening of the westerlies and trade winds during AMV+, the vertical cold advection due to Ekman divergence becomes significantly weaker during positive AMV, resulting in warm SSTAs. In addition to the Wind-Evaporation-SST feedback, this Wind-upwelling-SST feedback associated with equatorial convergence further intensifies SSTAs and the tropical positive feedback. Further investigation reveals that the reason for the asymmetric AMV+ preference is in the nonlinear feedback mechanism: positive SST anomalies strengthen the stratification to help local warming driven by anomalous downwelling, whereas negative SST anomalies weaken the stratification and hinder local cooling driven by anomalous upwelling.
Field quantification of the water productivity of a peach orchard within an arid climate zone.
Authors: Toumi Ines , Ghrab Mohamed , Zarrouk Olfa , Nagaz Kamel
Published: March 2024

Irrigation management is the key to improving water productivity in fruit orchards growing under marginal conditions in dry areas where the water for irrigation is significantly decreasing. The aim of this work was to determine the yield response to variable water supply of an early maturing peach orchard and to assess the water productivity in an environment where the water is extremely scarce. Field experiments were carried out on peach trees for a private farm in south of Tunisia for two relevant period (2010/2011 and 2013/2015), in an area with sandy soil, hot summer and mild winter conditions.  Old trees were irrigated with different irrigation strategies 100%, 60%, 50%, 40% and 20% of the estimated ETc. In the first experimental period, Flordasar peach trees were subjected to DI40, DI60 and DI20 and gave a variable yields ranged between 23-30 Kg tree-1. The highest WP values were obtained for DI60 et DI40, respectively 4.26 and 3.63 kg m-3. However, experimental work in peach trees under DI50 with two irrigation strategies, average water productivity varied between 2.21-2.24 and 2.81-3.14 kg m-3 respectively when yields was increased from 25.5 to 34.1 Kg tree-1. The yield reductions under low to severe water defcits accompanied by gains in WP may be justifable in the light of anticipated water restriction.
An Integrated Modelling Approach to Support Sustainable Water Resources Management and Climate Change Adaptation for Irrigated Agriculture in the Nile Delta, Egypt.
Authors: Gomaa Samar , Fleskens Luuk , Carvalho Nunes Joao , Badr Marmar
Published: March 2024

Climate change dominates the nexus between water resources management needed for farm farmland irrigation and food security insurance. The challenge increases when the population proliferates and the demand for food and water rises. This study will explore how climate change may affect food production and water use in the Nile Delta, Egypt, through higher temperatures and sea level rise. It also aims to investigate the best management practices (BMPs) that can be used to tackle these issues. In the Delta, where irrigated agriculture is practiced, sea level rise is a major potential impact of climate change since it significantly impacts the salinity of the water and soil. Furthermore, higher temperatures directly influence evapotranspiration, a crucial component of crop yields and water balance. To determine this interdisciplinary nexus between climate, water, and food, integrated hydro/hydrogeological and crop models will be created by calibrating and simulating the current baseline situation. For that purpose, a basic crop model will be merged with the coupled SWAT_MODFLOW hydro(geo)logical simulation software. Additionally, a range of forecasting scenarios will be run to represent the impact of multiple climate change scenarios. The outcomes of operated scenarios will be evaluated regarding socioeconomic and environmental aspects to support the decision-making process and define how far the BMPs can be implemented on ground in this study area.
Performance Assessment of CIMI Electron Precipitation During Geomagnetic Storm
Authors: Sur Dibyendu , Dorelli John C. , Fok Mei-Ching , Buzulukova Natalia Y.
Published: March 2024

The Comprehensive Inner Magnetosphere-Ionosphere Model (CIMI) is designed by coupling the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model (Fok et al., Journal of Geophysical Research: Space Physics, 119, 2014). The model provides electron and ion distribution functions in Earth’s radiation belt, ring current, estimates energies of precipitated electrons and ions in the ionosphere, calculates plasmaspheric density, ionospheric height-integrated Hall and Pedersen conductivities, ionospheric convection potentials. An important feature of CIMI model is calculation of electron precipitation from diffusion-convection equation that accounts both for particle drift in the inner magnetosphere and wave-particle interactions through various plasma waves. In this paper, the performance of the CIMI in terms of precipitating particle energy distribution is evaluated during the geomagnetic disturbed period of May 31 – June 1, 2013 (minimum Dst = -124nT). The performance of CIMI is observed in correspondence with Defense Meteorological Satellite Program (DMSP) satellite observations. Precipitated electrons (30 keV > E > 500eV) from Earth’s plasma sheet go through wave-particle interactions and produce diffuse aurora, that can be simulated with CIMI model. We compare CIMI electron precipitation energy channels for DMSP energy bins and analyze CIMI performance for different energy bins, mean energy and for the total integrated energy flux. In addition, CIMI model has different options for ionospheric conductance model: 1) empirical model of Hardy et al. (Journal of Geophysical Research: Space Physics, 92, 1987) that depends on Kp-index, and 2) Robinson's formulation (Robinson et al., Journal of Geophysical Research: Space Physics, 92, 1987) where ionospheric conductance depends on electron precipitation mean energy and total energy flux. We study CIMI model performance for two different models of ionospheric conductance and evaluate the feedback of electron precipitation on the ring current and ionospheric electric field.
Quantifying the spatial inhomogeneity of ice concentration in mixed-phase stratiform clouds using airborne observations
Authors: Yin Yan , Yang Jing , Deng Yuting , Jing Xiaoqin
Published: March 2024

The distribution of ice particles strongly affects the microphysical processes in mixed-phase clouds, but the inhomogeneity of ice distribution is not well understood. In this presentation the inhomogeneity and clustering of ice distribution in a stratiform cloud system is quantitatively analyzed using the pair correlation function (PCF) method, based on airborne in-situ measurements from northeast China. The results show that ice clusters on scales of a few kilometers dominate the inhomogeneity of the ice distribution. Due to the cumulative impact of ice clusters on different scales, the probability of finding relative high ice concentration within a lag of 80 m can be enhanced by 0.1 to 3.5 times. On average, the scale of ice cluster is ~100 m for a sampling distance of 1 km, and increases to 3.2 km for a sampling distance of 20 km. It is also found that the ice growth is not fast enough to cluster the ice water content (IWC), and the inhomogeneity of IWC is strongly influenced by ice generation in addition to ice growth in the observed clouds. The results provide potentially important information to improve the parameterizations of microphysics in numerical weather prediction and climate models.
Spatial-temporal variation of estuarine acidification in the southeastern Yellow Sea, Korea
Authors: Choi Yujeong , Kim Hyebin Kim , Kim Tae-Hoon
Published: March 2024

Geographically, an estuary is a transition zone where river water and seawater mix. In estuaries, where river water and sea water meet, acidification can occur due to carbon dioxide (CO2) changes due to strong horizontal stratification, long residence time, eutrophication, and weak acid-base buffering capacity.Despite the potential consequences, studies on acidification in Korean estuaries are notably scarce. This research focuses on the seasonal variations in aragonite saturation in the Han River estuary (an open estuary), and the Geum River and Yeongsan River estuaries (constrained by estuary dams) to assess the status of estuary acidification.Seasonal changes in aragonite saturation (Ωarg) recorded values of 1.5±0.5, 1.8±0.8, and 2.1±0.4 at the mouths of the Han River (HRE), Geum River (GRE), and Yeongsan River estuaries (YRE), respectively. Acidification was weak at the YRE, where dissolved inorganic carbon and total alkalinity were high. Conversely, acidification was pronounced at the HRE, where dissolved inorganic carbon (DIC) and total alkalinity (ALK) were low. Remarkably, downstream areas of the estuary, particularly those near large cities like Seoul, exhibited heightened vulnerability to acidification.In all three estuaries, aragonite saturation was lower in the upper reaches, influenced by river water with weaker acid-base buffering capacity than in the lower reaches. This underscores the potential for estuarine acidification to either worsen or alleviate based on future changes in the river's carbonate system, nutrient supply rates, and biological communities.Should estuary acidification intensify, the buffering capacity of estuaries will be compromised, potentially leading to the transfer of acidification to the ocean. This research sheds light on the intricate dynamics of estuarine acidification and emphasizes the need for continued monitoring and understanding of these crucial ecosystems.
Impacts of Direct Assimilation of the FY-4A/GIIRS Long-Wave Temperature Sounding Channel Data on Forecasting Typhoon In-Fa (2021)
Authors: Zhang Lei , Niu Zeyi , Weng Fuzhong , Dong Peiming , Huang Wei , Zhu Jia
Published: March 2024

The Advanced Weather Research Forecast model (WRF-ARW) is used to investigate the potential impacts of assimilating the FengYun-4A (FY-4A) Geostationary Interferometric Infrared Sounder (GIIRS) long-wave temperature sounding channel data on prediction of Typhoon In-Fa (2021). In addition, a series of data assimilation experiments are conducted to demonstrate the added value of the FY-4A/GIIRS data assimilation for typhoon forecasts. It is shown that the higher spectral resolution and broader coverage of GIIRS radiance data can positively impact the model analysis and forecasts with larger temperature and moisture increments at the initial time of simulations, thus producing the better simulation for typhoon warm core aloft, vortex wind structure and spiral rainfall band. Moreover, the assimilation of the GIIRS data can also lead to better storm steering flows and consequently better typhoon track forecasts. Overall, the assimilation of FY-4A/GIIRS temperature sounding channel data shows some added values to improve the track and storm structure forecasts of Typhoon In-Fa.
Effect of interdecadal variation in southern Indian Ocean SST on the relationship between ENSO and summer precipitation in the Asian-Pacific monsoon region
Authors: Gao Ya
Published: March 2024

The relationships between the El Niño-Southern Oscillation (ENSO), Asian-Pacific region summer precipitation and its corresponding atmospheric circulations exhibit interdecadal changes. From the early 1990s to the early 2000s, these relationships were significant. Therefore, we divided this time frame into three periods for analysis: 1979–1991 (P1), 1992–2005 (P2), and 2006–2019 (P3). The possible mechanism underlying these relationships is as follows: the southern Indian Ocean sea surface temperature (SST) over the east of Madagascar exhibits interdecadal variation. During P2, the SST was relatively cold, which induced an anomalously high Mascarene High (MH). The strengthened MH enhanced the Somali jet and Indian monsoon westerlies, which intensified the strong center of the Indian Ocean Walker circulation. Therefore, owing to the strength and location changes of the Indian Walker circulation and the Walker circulation, the connection between the ENSO and the western Pacific vertical motions strengthened, resulting in the close relationship of the ENSO with the atmospheric circulation over the Asian-Pacific region. Hence, ENSO can influence a north-south tripole pattern of precipitation over the Asian-Pacific monsoon region through local vertical activities and meridional Hadley circulation over western Pacific. Numerical experiments using an atmospheric general circulation model, with prescribed three times southern Indian Ocean SST anomalies of 1995–2005 relative to 1979–2019, also lend support to the southern Indian Ocean SST’s contribution to modulating the relationship between ENSO and summer precipitation over the Asian-Pacific monsoon region.
Analysis challenges for spaceborne multi-technique mass-change measurement: Mechanisms and mitigation
Authors: Bettadpur Srinivas , Wang Furun , Childress NIcholas , Krichman Ben , Jacob Geethu
Published: March 2024

Considerable research is underway in the satellite geodesy, spaceflight engineering, and high-precision metrology community that brings to bear modern technology to next generation mass-change estimation. This is motivated by a consensus community desire for ever increasing resolution and accuracy of global mass change - an essential climate variable - for understanding and inference of the Earth system at all spatio-temporal scales.The infusion of high-precision modern technology brings with it additional challenges in the data analysis including fundamental enabling analyses such as attitude and orbit determination, modeling of the observation and its connection to the gravity field parameters, and estimation techniques to maximize the fidelity of spatial patterns and signal amplitudes in estimated mass-change fields.In this paper, we report on our investigations into the mechanisms of aliasing - one of the most visible challenges in mass-change estimation from satellite gravity observations. In prior work, we have presented symptomatic assessments of how aliasing can have orthogonal impacts on gravity field estimated from low-low satellite-to-satellite (SST) tracking and from gravity gradiometry (GG), and shown how a combination of the two in a hybrid configuration can offer the best of both techniques. In this follow-up paper, we present results of closer investigations into the mechanisms of aliasing and their differential impacts on SST and GG, and what this suggests for mitigation in future multi-technique mass-change measurement environment. These results form the basis for recommendations of analysis techniques such as appropriate modifications to the variational methods, scoping the requirements on prior knowledge of rapid mass variability that is the principal cause of aliasing errors, and their mitigation in estimation techniques.
Significant subglacial and proglacial lake drainages in the Canadian Arctic identified by time-stamped ArcticDEM strips
Authors: Zheng Whyjay , Van Wychen Wesley
Published: March 2024

Active subglacial and proglacial lakes drain and fill constantly, contributing to glacier and ice sheet mass balance in a way that is not always easy to quantify. Active subglacial lakes account for about 20% of the first worldwide subglacial lake inventory (published by Livingstone et al., 2022); however, none have been previously identified in the Canadian Arctic. Here, we report at least 28 drainage and fill events identified by analyzing time-stamped ArcticDEM elevation data. We stack all the available 2-m DEM strips (23,691 in total) from the latest ArcticDEM release (October 2022) and calculate the elevation change rate at every 15-m sized pixel in a reference grid. Glacier areas with the following signals are interpreted to be associated with the lake drainage or refill beneath the ice: (1) a significantly higher elevation change rate than the neighboring regions within the same glacier catchment, and (2) no adjacent zones showing reversed elevation change (to avoid surge event being misclassified). If such an area touches the glacier terminus, we interpret the elevation change to be governed by a proglacial lake where the floating ice terminus rises and falls when the lake level changes. These drainage and refill events are scattered throughout the region, from the North Ellesmere Icefields to Penny Ice Cap (South Baffin Island). Almost none of the lake locations have been previously reported, probably due to their small size (a few kilometers wide on average), but some of them caused significant ice elevation drops of up to 100 meters during a drainage event. It is not clear whether these significant drainage events produced outburst floods due to temporal sampling gaps in the data. Nevertheless, the water mass lost or gained during the events should be independently calculated from the land ice budget, and we should keep monitoring these newly discovered lakes for their potential impact on the ice flow dynamics and localized mass balances, especially in the context of rapid Arctic warming.
Sulfur and oxygen isotope ratios constrain riverine sulfate sources and terrestrial pyrite oxidation
Authors: Hu Huiying , Zhao Changqiu , Xu Sen , Wei Rongfei , Zerizghi Teklit , Tan Qiyu , Guo Qingjun
Published: March 2024

Pyrite oxidation, coupled with carbonate weathering, can be a source of carbon dioxide (CO2) in the atmosphere over geological timescales. However, this source of CO2 is an important but not entirely understood component of the long-term carbon cycle. The exact identification of the riverine sulfate sources and terrestrial pyrite weathering flux is crucial for a quantitative understanding of this source, but it still faces great challenges. Sulfur and oxygen isotope ratios are widely used to constrain sulfate sources. Here, we reviewed the effect of pyrite oxidation on the carbon cycle and synthesized sulfur isotope and oxygen isotope data for global rivers. We also figured out the fluxes of riverine sulfate caused by pyrite oxidation in various rivers around the world using a Bayesian model that is based on the sulfur and oxygen isotope ratios in riverine sulfates and local end elements. The highest pyrite-derived sulfate fluxes were found in the Mississippi River (198.3 ± 37.8 Gmol SO42-year-1). Higher pyrite oxidation rates occurred in areas with higher runoff rates, and global climate change may have also affected pyrite oxidation rates. This may assist in re-evaluating the role of chemical weathering on the carbon cycle and improve the theory of the carbon cycle.
Greenhouse gas and short-lived pollutants in the Baltimore, MD and Washington, DC area: Coordinated measurements and models
Authors: Dickerson Russell , Ren Xinrong , Karion Anna , Shepson Paul , Stratton Phil , Sun Jiayang , Sayatan Sahu , He Hao , Daley Hannah
Published: March 2024

The cities of Baltimore, MD and Washington, DC generate substantial amounts of air pollutants with adverse effects on health and climate, but the magnitude and origins of these contaminants remain uncertain.  The State of Maryland has committed to reducing statewide greenhouse gas emissions by 60% (relative to 2006 levels) by the year 2031. A team of scientists from the Maryland Department of the Environment (MDE), the National Institute of Standards and Technology (NIST), the National Oceanic and Atmospheric Administration (NOAA), the University of Maryland, and Stony Brook University have established a coordinated program of measurements and models to quantify and allocate emissions.  These include observations from aircraft, a mobile laboratory, a tower array, and surface monitors as well as Lagrangian and Eulerian models.  Results thus far indicate that methane emissions substantially exceed initial, traditional, bottom-up, inventory data and that leakage from the natural gas delivery system and landfills are major sources.  Urban methane emissions show a strong seasonality, consistent with natural gas usage – the flux in winter was 44% greater than in summer.  Model inversions suggest urban methane emissions in Washington and Baltimore decreased by 4-5%/yr between 2018 and 2021.  Mobile laboratory measurements of GHGs and air pollutants such as black carbon with high temporal and spatial resolution reveal a variety of sources in densely populated urban residential areas related to traffic and industry and with implications for environmental justice.  Analysis of long-term monitoring data with clustering of trajectories identified dominant transport pathways and sources in upwind states that likely contribute in a major way to ambient methane concentrations in the Baltimore/Washington area – these include the Marcellus oil and gas plays in Pennsylvania and West Virginia as well as swine production in North Carolina.  Ongoing and future work includes developing a landfill as a testbed for emissions quantification and control and use of carbon and hydrogen isotopes to partition fossil and biogenic emissions and biogenic losses.  The combination of State, federal, and university resources makes for a powerful tool to tackle air quality and climate problems.  
Linking social and scientific efforts to address arsenic and heavy metals pollution in a mining area in Central Mexico
Authors: Armienta M. Aurora , Del Razo Luz Maria , Ledón Juan Manuel , Labastida Israel , Beltrán Margarita , Sosa Antonio , Morales-Arredondo Ivan , Aguayo Alejandra , Cruz Olivia , Neri Omar
Published: March 2024

For many years, the high concentration of arsenic (As) in deep groundwater, up to 1.2 mg/L, has posed a health risk to the residents of Zimapán, a mining town in Mexico with a population of about 40,000. Additionally, ore processing, mainly through selective flotation, has resulted in the production of thousands of tons of tailings, which have accumulated in the outskirts of the town, causing damage to soils and shallow wells. To address this environmental issue, Mexican and international scientists have conducted studies focused on various environmental compartments. Since the earliest studies, whose aim was to identify the source of As pollution, the local authorities and people of Zimapán have been involved in the research activities.Three years ago, a collaborative working group was formed, including local authorities, scientific and social researchers from various universities, local social organizations, and individuals who were committed to the environment (Environmental Research Network, REA). Their participation has included support for field activities, communication and exchange of knowledge, and the promotion of alternatives identified by scientific and social efforts to high-level authorities.The outcomes of their work have been significant. They have rehabilitated the As removal treatment plant, which was installed about 15 years earlier as a result of this science-social collaboration. Additionally, they have identified local limestone as an option to treat tainted water and acid mine drainage. They have also supported the municipality in building rain harvesting systems in two schools to provide safe water to students. Moreover, they have interacted with miners to propose alternatives to minimize the impact of the tailings, among other achievements. The quality of drinking water supplied to downtown Zimapán is not yet in line with the national As drinking water standards, which require the arsenic level to be below 0.025 mg/L. The current level of arsenic in the water varies between 0.2 and 0.4 mg/L, which is a significant improvement from the previous level of 1.2 mg/L. However, efforts are still underway to achieve a safe water supply that meets the national standards. The REA has been effective in reducing the arsenic concentration in the water and has proven to be a viable social-scientific method for creating a healthier environment in the locality. It is also a model for other areas in Mexico that are impacted by arsenic contamination.