bluuebunny/crossref_metadata_2025 huggingface dataset:
Feature engineering strategies based on GIS and the SCS-CN method for improving hydrological forecasting in a complex mountain basin
Authors: Merizalde María José , Muñoz Paul , Corzo Gerald , Célleri Rolando
Published: February 2023

Hydrological modeling and forecasting are important tools for adequate water resources management, especially in complex systems (basins) characterized by high spatio-temporal variability of runoff driving forces, landscape heterogeneity, and insufficient hydrometeorological monitoring. Yet, during the last decades, the use of machine learning (ML) techniques has become popular for runoff forecasting, and the current research trend focuses on performing feature engineering (FE) strategies aimed both at improving forecasting efficiencies and allowing model interpretation. Here, we employed three ML techniques, the Random Forest (RF) algorithm, traditional Artificial Neural Networks (ANN), and specialized Long-Short Term Memory (LSTM) networks, assisted by FE strategies for developing short-term runoff forecasting models for a 3300-km2 complex basin representative of the tropical Andes of Ecuador. We exploited the information of two readily-available satellite products, the IMERG and GSMaP to overcome the absence of ground precipitation data, and the FE strategies proposed were based on GIS and the Soil Conservation Service Curve Number (SCS-CN) method to synthesize the use of land use and land cover, soil types, slope, among other hydrological concepts. To assess the forecasting improvement, we contrasted a set of efficiency metrics calculated both for the developed specialized models and for referential models without the application of  FE strategies. In terms of results, we were first able to develop accurate forecasting models by exploiting precipitation satellite data powered by ML techniques with different complexity levels. Second, the referential forecasting models reached efficiencies (Nash-Sutcliffe efficiency, NSE) varying from 0.9 (1-hour lead time) to 0.5 (11-hours), which were comparable for the RF, ANN, and LSTM techniques. Whereas for the specialized models, we found an improvement of 5–20 % in NSE-values for all lead times. The proposed methodology and the insights of this study provide hydrologists with new tools for developing short-term runoff forecasting systems in complex basins otherwise limited by data scarcity and model complexity issues.
Is a more physical representation of aerosol activation needed for fog forecasting in perspective of climate change?
Authors: Bhowmik Dr. Moumita , Hazra Dr. Anupam , Ghude Dr. Sachin D.
Published: February 2023

With the changing climate, the study of fog formation is essential and needs of the hour, as the nature of fog has changed due to impact of complexity of natural and anthropogenic aerosols. Chemical and physical properties of condensation nuclei (CN) influence the formation of fog and thus visibility over India. The presences of ample water vapor in the air, microphysical and thermodynamic property of CN are crucial for the occurrence and sustenance of fog. The visibility parameterization is depending on the number of cloud droplets. The aerosol particle and conversion of aerosol to fog droplet, which requires external nuclei for water vapor to condensation, is controlled by the processes of condensation or diffusional growth. The condensation process is controlled by solute effect (Raoult's effect) and the curvature effect (Kelvin effect) and may happen over a pre-existing Aitken aerosol particle. The growth of droplets is determined by the size of CN and a droplet will always try to maintain an equilibrium state if the equilibrium supersaturation is less than the amount of water vapor available in the atmosphere. The Köhler curve portrays the evaporation of droplets under the “curvature effect” and the “solute effect”. Droplets with higher solute concentration have lower critical supersaturation values. Thus, hygroscopicity (κ), which is highly related to the activation of aerosols to CN, takes into account the contribution of aerosol particles to fog droplet formation. The κ-Köhler theory combining the Kelvin's equation and Raoult's law are used for the activation of a deliquesced aerosol particle, which is forming an aqueous solution droplet into a smaller cloud droplet. Hygroscopicity is linked with the water activity and thus the thermodynamics of solution governs the aerosols liquid water and hence, better understanding of hygroscopicity is essential in numerical model for the fog and visibility prediction. The microphysical properties of fog are also regulated by aerosol, which is more strongly reliant on concentration aerosols and its chemistry (hygroscopicity and water activity). The saturation value needed for fog formation can be brought down by aerosol number concentration. It is concluded that the complexity in fog and visibility forecasting is found to be high due to multiple factors having a role at multiple levels. We may propose a revised visibility parameterization over Indian subcontinent. 
Assessing the Sustainability in Water Use under Different Agricultural Management Planning in Yeongsan-River Basin, South Korea
Authors: Jeong Yujeong
Published: February 2023

Assessing the Sustainability in Water Use under Different Agricultural Management Planning in Yeongsan-River Basin, South Korea Yujong Jeong1, Hyun-woo Jo1, YanYan1, Minwoo Noh1, Woo-Kyun Lee1* 1 Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea*E-mail: leewk@korea.ac.kr(Address: Korea University, Anamro 145, Seongbukgu, Seoul 02841, Republic of Korea) Abstract:From the past, South Korea has been experiencing high level of water stress as reported by WRI, in 2013, and chronically imbalanced spatiotemporal water allocation. Yeongsan-river basin, where the biggest national breadbasket is located, is facing unequal water allocation among different water uses and inefficient water management under episodic water shortage conditions. Therefore, the main objective of this study was to analyse current water management and allocation scheme, and to evaluate 3 different agricultural management plans in terms of efficiency and equity. The Soil and Water Assessment Tool(SWAT) was applied to simulate the hydrological process and crop yield in the basin. The model was calibrated and validated using observed outflows to set adequate system parameters for the entire watershed. Crop water productivity and spatial-temporal-sectoral water distribution are utilized as the indices to evaluate different agricultural strategies. The results suggested that there was potential to improve both crop productivity and water allocation at the same time with the suggested plannings. Crop water productivity increased in all three strategies in order of on-farm management measures (precise agriculture), crop diversification (replacing rice to beans) and agroforestry (mixing trees and crops). The crop water productivity of on-farm measurement ranges from 5t/L to 13t/L and rises about 20% on average. In addition, it is found that applying the combination of different agricultural management measures could achieve better water allocation in terms of space and time, and between agriculture and ecosystem. The outcomes of this study can serve scientific-evidence policy and decision-making systems for sustainable agricultural society and ecosystem.Keywords: Hydrological Modelling, SWAT, Crop water productivity, Water allocation, Agricultural Management Planning, Yeongsan-River BasinAcknowledgements: This work was supported under the framework of international cooperation program managed by the National Research Foundation of Korea (No. 2021K2A9A1A02101519).  
Seismic Evidence of Slab Segmentation and Melt Focusing Atop the 410-km Discontinuity in NE Asia
Authors: Song Jung-Hun , Kim Seongryong , Rhie Junkee
Published: February 2023

The geometry of subducting slabs is largely controlled by mantle rheology and time evolving processes of surface plate boundaries. Imaging of a detailed slab distribution and its surrounding can provide information of physical, chemical, and dynamical properties of the upper mantle. Based on new high-resolution 3-D tomography of subducting Pacific slab in northeast Asia, we revealed a prominent gap within the stagnant portions of the slab showing an abrupt change in its lateral trends that follow the trace of plate junctions associated with plate reorganization at the western Pacific margin during the Cenozoic. Focused partial melting above the slab gap was inferred based on the spatial coincidence between the high Vp/Vs anomaly and the negative reflectivities above the 410-km discontinuity from local receiver function studies. The slab gap is possibly filled with low-velocity anomalies within the MTZ as evidenced by wavefield focusing of teleseismic body waves and absolute velocity imaging from previous studies. We explain the spatial coincidence between the low-velocity anomaly within the MTZ and the focused melt layer above the MTZ by the process of mantle dynamics related with secular variation of slab geometries by tearing. Isolated low-velocity anomalies within the MTZ imaged by seismic tomography without previous thermal disturbances (e.g., hot plume) are suggested to be the products of distinct MTZ compositions disturbed by former nearby slab subductions. Our results suggest a close dynamical relationship between the subducting slab and the MTZ, which promotes the formation of multi-scale chemically distinct domains in the deeper upper mantle.
Research in Volcanology: where, when, and by whom? A global bibliometric analysis
Authors: Jenkins Susanna F. , Lerner Geoffrey A. , Williams George T. , Meredith Elinor S. , Barclay Jenni
Published: February 2023

The global and transdisciplinary nature of volcanology means that research takes place across institutions in a wide variety of locations around the world. The concentration of volcanic activity within certain regions means that researchers frequently conduct research outside their own borders. Collaboration between international and local researchers has the potential to produce mutual benefit and improve research. For local scientists, international collaboration can provide niche expertise that may not be currently available in the region where the volcano is located, in addition to resources, analyses, or equipment. For international researchers, in addition to different scientific perspectives, collaboration with local scientists can provide vital knowledge of local and regional information, access to field sites, and greater research relevance to the communities and organizations the research is often intended to benefit.Despite these noted benefits, there is often a lack of inclusivity of local scientists in international research. In this study we use a bibliometric approach to understand who is doing and leading volcanic research, and in which countries the research is taking place. We assessed the metadata of ~24,000 volcanological works from 1901-2021 with 768 volcanoes identified across 68 countries. Our evaluation of affiliations shows that 40% of articles that name a volcano do not include any authors affiliated with the volcano’s country. We also look at case studies of island territories to explore to what extent local scientists are involved in doing research compared to the mainland or foreign countries. We find that only 23% of studies on volcanoes located on island territories have an author affiliated with the territory. Our assessment of bibliometric data provides insights and support for ongoing conversations on the inclusiveness of international research, both spatially and temporally, and can be used to identify geographical areas for improvement, as well as trends in inclusion and leadership.
Understanding vegetation drought legacy effects on carbon cycling using observations from multiple platforms
Authors: Yao Yitong , Wang Yujie , Yin Yi , Frankenberg Christian
Published: February 2023

Drought legacy effects refer to the lasting impacts on the carbon cycle from droughts, being a prime uncertainty in predicting future land carbon sink in a changing climate. While previous studies have been focusing on the drought legacy effects on tree growth using tree ring chronologies, the rapid developments of site and satellite observations over the past decades provide us new opportunities to investigate the effects with improved temporal and spatial coverage. For example, retrievals of canopy structure, photosynthesis, evapotranspiration, and vegetation water content would allow for evaluating the differences in recovery processes in magnitude, timing and duration of the legacy effects. Potential asynchrony and divergence among these multiple legacy indicators result in large uncertainties in understanding the full range of vegetation responses to drought. To address this issue, this study aims to leverage the development of a new generation Earth system model (CliMA) in combination with site and satellite observations to understand the various legacy effects on carbon sink responses from site to regional scales. Through investigating the temporal and spatial patterns of legacy effects, our work will gain a comprehensive understanding of drought related carbon cycle feedback and benefit science-based decision making facing changing climate, especially extreme events. 
Deep learning parameterization of small-scale vertical velocity variability for atmospheric models
Authors: Barahona Donifan , Breen Katherine , Kalesse-Los Heike
Published: February 2023

Small-scale fluctuations in vertical wind velocity, unresolved by climate and weather forecast models play a particularly important role in determining vapor and tracer fluxes, turbulence and cloud formation. Fluctuations in vertical wind velocity are challenging to represent since they depend on orography, large scale circulation features, convection and wind shear. Parameterizations developed using data retrieved at specific locations typically lack generalization and may introduce error when applied on a wide range of different conditions. Retrievals of vertical wind velocity are also difficult and subject to large uncertainty. This work develops a new data-driven, neural network representation of subgrid scale variability in vertical wind velocity. Using a novel deep learning technique, the new parameterization merges data from high-resolution global cloud resolving model simulations with high frequency Radar and Lidar retrievals.  Our method aims to reproduce observed statistics rather than fitting individual measurements. Hence it is resilient to experimental uncertainty and robust to generalization. The neural network parameterization can be driven by weather forecast and reanalysis products to make real time estimations. It is shown that the new parameterization generalizes well outside of the training data and reproduces much better the statistics of vertical wind velocity than purely data-driven models.
Initial radiocarbon (14C) results of compound class persistence across a climate gradient in California grassland soils
Authors: Grant Katherine , Repasch Marisa , Finstad Kari , Broek Taylor , Pett-Ridge Jennifer , McFarlane Karis
Published: February 2023

Soils mediate the rapid cycling of carbon through the critical zone. Soil organic carbon (SOC) is composed of a complex mixture of plant and microbial derived organic compounds with distinct cycling timescales. The residence time of individual SOC components depends on a combination of factors, including compound reactivity, mineral association, and climate conditions, making it difficult to accurately quantify. However, radiocarbon analysis of specific compound classes can disentangle the mixture of SOC ages within a single sample. We modified methods to measure the Δ14C of distinct compound classes (lipids, amino acids, and carbohydrates) from bulk and physically fractionated grassland soils. Additionally, we measured the Δ14C of the water-extractable fraction (WEOC) and the residual acid-insoluble fraction. Samples were collected from a series of grassland meadows across California ranging in climatic conditions including temperature and precipitation. Sites include grassland meadows in Angelo Coast Range Reserve, Hopland Extension Reserve and Sedgwick reserve, and which receives 2160, 940, and 380 mm yr-1 of rainfall and is dominated by Avena spp. We sampled 1m soil pits by ~10cm intervals to study changes in SOC persistence with depth. We used solid state 13C-NMR to measure the relative abundance of the target compound classes in soil. The Δ14C of bulk soil decreased from about +50‰ to about +10‰ in the O-horizons to a range of about -150‰ to about -650‰ in the deepest horizons. At the Hopland site, the clay fraction (<63μm) had higher Δ14C values than both the bulk (<2mm) and sand (<2mm to >63μm) fractions. WEOC Δ14C values ranged from modern to about -45.6‰. Δ14C values of total extracted lipids ranged from 36±4‰ at the surface to -215±3‰ at depth. Quantifying the age distribution of distinct compound classes gives a direct measurement of the persistence between these phases.
Volatile Organic Compound Measurements and Oxidant Modeling at a Remote Mountain Site in the western North Pacific
Authors: Griffith Stephen M. , Liu Wen-Tzu , Chen Fang-I , Hidayati Elmia , Chang Chih-Chung , Wang Jia-Lin , Lin Neng-Huei
Published: February 2023

Anthropogenic pollution, including primary compounds such as nitrogen oxides (NOx) and organics, but also secondary pollutants such as ozone, are a threat to sensitive mountain ecosystems, which are already under continued threat of diminished area, due to climate change. This study analyzes two days of volatile organic compound (VOC) concentrations, including a limited set of carbonyls, at the Lulin Atmospheric Background Station (LABS; 2,862 meters asl), which is a well-known remote sub-tropical site that receives long-range transported air masses from various clean and polluted origins. VOCs were sampled in a canister and analyzed by GC-MS/FID, while carbonyls were trapped on Supelco DNPH-coated cartridges and quantified by HPLC-UV. Routine LABS measurements of ozone, CO, and PM2.5 were also utilized; Copernicus Atmospheric Monitoring Service (CAMS) reanalysis NOx and HNO3 concentrations were further incorporated into an oxidant modeling analysis. In comparing the two sampling days, the first day was characterized by hazier conditions (~3 times higher PM2.5 concentrations) and 2-3 times higher VOC and CO concentrations and calculated OH reactivity values. Based on a HYSPLIT back-trajectory analysis, the first day was influenced by air that had a longer residence time at lower altitudes over South China, while the second day was characterized by higher level transport. Also influential at the site are subsidence events that bring drier air that can contain high ozone and NOy species. The measurement and reanalysis data were incorporated into a 0-dimensional modeling analysis (F0AM) of the gas-phase oxidation chemistry in order to further characterize the different air masses that influence this sensitive mountain area. While the first day also was simulated to have higher level of ozone production, the second day captured an afternoon spike in pollutants and ozone production that was likely driven by upslope mountain valley air sourced for lower altitudes in Taiwan. Thus, the oxidation potential in this environment is characterized by large swings driven by local upslope pollution, subsidence events, and long-range transported pollution from the Asian continent, which ultimately dictate the pollutant exposure for this sensitive ecosystem.
Teleseismic Rayleigh-wave phase velocity tomography in the southern Korean Peninsula
Authors: Kwon Joa , Yoo Hyun Jae , Kang Tae-Seob , Kim Seongryong , Lee Sang-Jun , Rhie Junkee
Published: February 2023

Surface wave dispersion is one of the essential means to study the structure of Earth’s crust and upper mantle. However, complicated structures of the Earth’s surface cause multipathing effects that make accurate phase measurement difficult. In this study, teleseismic Rayleigh-wave tomography was performed to estimate the crustal velocity structure of the southern part of the Korean Peninsula using phase differences between station pairs in a dense array instead of absolute phase arrival times and amplitudes. In order to estimate the phase change across the seismic array, the phase delay time between the nearby stations is inverted using the Eikonal equation. The structural velocity that is more consistent with the actual substructure is derived from adding the amplitude term to the inversion process by the Helmholtz equation. The earthquake data of 219 teleseismic events recorded at 146 broadband stations in the Korean Peninsula and Tsushima Island from 2018 to 2020 were used to build up Rayleigh wave phase velocity maps between the periods of 10 to 100 seconds. The teleseismic events were chosen with a magnitude of 6.0 or larger, a hypocenter depth shallower than 50 km, and an epicentral distance between 5˚ and 115˚. The final phase velocity maps for each period were obtained by stacking the results of the tomographic inversions of each event. Bayesian 1-D joint inversion using the phase velocity data of this study, those from ambient noise tomography and global velocity models is performed to obtain 3-D shear wave velocity models of the study region. The derived shear wave velocity maps show the clear boundary of velocity anomalies at short periods (≤ 20 s), which is parallel with the major geological structures, such as the Gyeongsang Basin and the Okcheon fold belt. At longer periods, we observe a significant velocity contrast between the southwestern and the northeastern region of the Korean Peninsula.
Uncertainty quantification for the retrieval of cloud properties with deep neural networks for TROPOMI / Sentinel-5 Precursor
Authors: Romahn Fabian , Loyola Diego , Doicu Adrian , Molina García Víctor , Lutz Ronny , Argyrouli Athina
Published: February 2023

Due to their fast computational performance, neural networks (NNs) are nowadays commonly used in the context of remote sensing. The issue of performance is especially important in the context of big data and operational processing. Classical retrieval algorithms often use a radiative transfer model (RTM) as forward model with which an optimization algorithm can then solve the inverse problem of inferring the quantities of interest from the measured spectra. However, these RTMs are usually computationally very expensive and therefore replacing them by a NN is desirable to increase performance. But the application of NNs is not straightforward and there are at least two main approaches:1. NNs used as forward model, where a NN approximates the radiative transfer model and can thus replace it in the inversion algorithm2. NNs for solving the inverse problem, where a NN is trained to infer the atmospheric parameters from the measurement directlyThe first approach is more straightforward to apply. However, the inversion algorithm still faces many challenges, as the spectral fitting problem is generally ill-posed. Therefore, local minima are possible and the results often depend on the selection of the a-priori values for the retrieval parameters.For the second case, some of these issues can be avoided: no a-priori values are necessary, and as the training of the NN is performed globally, i.e. for many training samples at once, this approach is potentially less affected by local minima. However, due to the black-box nature of a NN, no indication about the quality of the results is available. In order to address this issue, novel methods like Bayesian neural networks (BNNs) or invertible neural networks (INNs) have been presented in recent years. This allows the characterization of the retrieved values by an estimate of uncertainty describing a range of values that are probable to produce the observed measurement. We apply and evaluate these new BNN and INN methods for the retrieval of cloud properties from TROPOMI in order to demonstrate their potential as operational algorithms for current (Sentinel-5P) and future (Sentinel-4 and Sentinel-5) Copernicus atmospheric composition missions.
A multi-well tracer test for characterizing the preferential flow of the shallow aquifers in the Tatun Volcanic Area
Authors: Tseng Pei-Yun , Chen Yi-Ling , kuo Ching-Huei
Published: February 2023

A multi-well tracer test was conducted in a volcanic area where is mainly composed of sedimentary rocks units and tuff breccia with attitude of the N46E, 18S. in Northern Taiwan. The distance between the injection well #14 and monitoring wells #-2 and #6 are 236 and 682 m, respectively.A Bimodal breakthrough curve was received from both wells indicating the existence of more than one channel in the system. Surprisingly, the first peak arrives simultaneously at both wells with almost a 3 times difference in distance. A much fast flow between Well #14 and #6 was found. This result matches the local orientation of the formation and may show strong geology control groundwater flow of the region resulting in a preferential flow. With the moment analysis, the difference in communication between the injection well and the two monitoring wells can be depicted by 50% of the flow circulation coming from 25% and 30% storage capacity for Well #2 and Well #6, respectively implying that groundwater flows through more fractures between Well #14 and 6.  An obvious tailing breakthrough curve of Well #6 also reflects more fractures than that of Well #2.
Wave Propagation and Growth Dependency to Environmental Moisture: A Case of an Atlantic Tropical Cyclogenesis
Authors: Núñez Ocasio Kelly , Davis Chris
Published: February 2023

In a recent model evaluation of the African Easterly Wave (AEW) that became Helene (pre-Helene; 2006) over the Atlantic, the wave was categorized as a mixed-off-equatorial moisture mode during tropical cyclogenesis as it evolved under weak temperature gradient balance. It was found that the simulated pre-Helene waves were more intense and overall slower than in ERA5, especially the wave that evolved in a more moisture-rich environment. The growth and propagation of the wave were related to the position of the convection with respect to the center of the wave vortex. The influence of environmental moisture on wave propagation before and during genesis remains an open question. Motivated by the recent findings, in this study, moisture sensitivity experiments are performed with a convection-permitting model to further evaluate the moisture dependency of the pre-Helene wave and later tropical cyclogenesis. The Model for Prediction Across Scales (MPAS) regional configuration is used to allow altering initial and lateral boundary conditions of relative humidity (RH) through the entire atmospheric column using ERA5 pressure-level data. Preliminary results reveal that over land the strength of the wave-trough meridional flow is related to mid-to-upper-level diabatic heating tendencies from clouds located in the northerly phase of the wave and to the lack of shallow convection within the vortex. In MOIST (RH x 1.2 experiment), the wave moves slower, yet organized convection propagates out of phase with the wave speed, ultimately weakening the wave and subsequent tropical cyclogenesis. In CONTROL, where the wave propagates faster, the phasing between wave and convection supports a stronger wave prior to genesis and ultimately genesis when compared to MOIST. A moister atmosphere (MOIST) favors a larger fraction of shallow convection (bottom heavy and weaker updrafts) at the center and ahead of the vortex, detraining the mid-troposphere and weakening the mid-tropospheric vorticity. This leads to a wave that weakens prior to genesis compared to CONTROL as well as a more abrupt decrease in speed prior to genesis. The lack of cloud microphysics heating tendencies in DRY (RH x 0.5 experiment) resulted in a weaker mid-to-upper-level circulation but stronger surface-to-low-level winds. The lack of moisture is detrimental to the simulated pre-Helene; however, a moister environment does not necessarily result in a more intense wave or tropical cyclogenesis event. A wave that propagates more slowly (‘moist wave’ versus ‘dry wave’), does not necessarily favor growth. For further growth, convection that is in phase with the vortex should be deep moist convection.
Exploring the Sudden Stratospheric Warming Events in High-top and Low-top Climate Model Large Ensembles
Authors: Liang Yu-Chiao , Wang Yi , Kwon Young-Oh , Frankignoul Claude , Polvani Lorenzo , Suo Lingling
Published: February 2023

Sudden stratospheric warming (SSW) events, followed by a characteristic circulation regime in the lower troposphere, are crucial for the subseasonal weather prediction. What remains controversial is whether or not increasing the height of top layer in a climate model and the vertical resolution improve the representation of SSW events and the subsequent influences on the near-surface climate. In this study, we examine the SSW events simulated in a high-top climate model (the Whole Atmosphere Community Climate Model version6, WACCM6) and those simulated in a low-top model (Community Atmosphere Model version 6, CAM6) with 30 ensemble members. The two sets of experiments are forced by identical observational sea-surface temperature and sea-ice concentration, as well as the radiative forcings, during the 1979-2013 period. We find that WACCM6 produces about two times more SSWs than CAM6 (i.e., 759 v.s. 357 events), and, in terms of occurring frequency, SSWs in WACCM6 happen about 7 times per decade, closer to the SSW frequency in reanalysis datasets. Analyses on the thermodynamical and dynamical components of SSWs, including the sea-level pressure precursor, the preceding Eliassen-Palm fluxes into the stratosphere, the stratospheric temperature increases, and the downward propagation features, reveal that WACCM6 in general gives weaker signals than CAM6. This is likely attributed to the weaker mean stratospheric circulation in WACCM6. We also find that the WACCM6-CAM6 differences can be amplified during the years of El Niño and La Niña events. Finally, we perform the vortex moments diagnostics to gain further insights into the vortex structure and separate the splitting and displacement SSWs. The diagnostics shows that CAM6 generates more symmetric polar vortices than WACCM6, while the vortices from CAM6 deviate less often from the North Pole. However, the ratio of displacement and splitting SSWs in both model is about 70%, larger than about 60% in reanalysis datasets. Our study suggests that the high-top configuration leads to better performance of stratospheric circulation variability.
Air quality deterioration episode associated with typhoon over the complex topographic environment in central Taiwan
Authors: Lin Chuan-Yao , Sheng Yang-Fang , Chen Wan-Chin , Chou Charles, C.K. , Chien Yi-Yun , Chen Wen-Mei
Published: February 2023

 Air pollution is typically at its lowest in Taiwan during summer. The mean concentrations of PM10, PM2.5, and daytime ozone (08:00–17:00 LST) during summer (June–August) over central Taiwan are 35–40 µg m-3, 18–22 µg m-3, and 30–42 ppb, respectively, between 2004 and 2019. Sampling analysis revealed that the contribution of organic carbon (OC) in PM2.5 could exceed 30% in urban and inland mountain sites during July in 2017 and 2018. Frequent episodes of air quality deterioration occur over the western plains of Taiwan when an easterly typhoon circulation interacts with the complex topographic structure of the island. We explored an episode of air quality deterioration that was associated with a typhoon between 15 and 17 July 2018, using the Weather Research Forecasting with Chemistry (WRF-Chem) model. The results indicated that the continual formation of low-pressure systems or typhoons in the area between Taiwan and Luzon island in the Philippines provided a strong easterly ambient flow, which lasted for an extended period between 15 and 17 July. The interaction between the easterly flow and Taiwan’s Central Mountain Range (CMR) resulted in stable weather conditions and weak wind speed in western Taiwan during the study period. Numerical modeling also indicated that a lee side vortex easily formation and the wind direction could be changed from southwesterly to northwesterly over central Taiwan because of the interaction between the typhoon circulation and the CMR. The northwesterly wind coupled with a sea breeze was conducive to the transport of air pollutants, from the coastal upstream industrial and urban areas to the inland area. The dynamic process for the wind direction changed given a reasonable explanation why the observed SO42- became the major contributor to PM2.5 during the episode. SO42- contribution proportions (%) to PM2.5 at the coastal, urban, and mountain sites were 9.4 µg m-3 (30.5%), 12.1 µg m-3 (29.9%), and 11.6 µg m-3 (29.7%), respectively. Moreover, the variation of the boundary layer height had a strong effect on the concentration level of both PM2.5 and ozone. The combination of the lee vortex and land-sea breeze, as well as the boundary layer development, were the key mechanisms in air pollutants accumulation and transport. As typhoons frequently occur around Taiwan during summer and fall, and their effect on the island’s air quality merits further research attention.
Garnet lu-hf speed dating: a novel method to rapidly resolve polymetamorphic histories
Authors: Simpson Alexander , Glorie Stijn , Hand Martin , Spandler Carl , Gilbert Sarah
Published: February 2023

GARNET LU-HF SPEED DATING: A NOVEL METHOD TO RAPIDLY RESOLVE POLYMETAMORPHIC HISTORIESAlexander Simpsona,, Stijn Gloriea,, Martin Handa,, Carl Spandlera, Sarah Gilberta,aDepartment of Earth Sciences, School of Physical Sciences, The University of Adelaide, Adelaide SA-5005, AustraliaAbstractGarnet is a remarkably useful mineral in the study of crustal and lithospheric-scale tectonic systems. A vast body of knowledge exists on its thermodynamic properties, meaning garnet is widely used for determining pressure-temperature conditions.  Traditional methods to date garnet (e.g. Lu-Hf and Sm-Nd) are time consuming and commonly volumetrically imprecise.  Consequently, garnet is generally now dated indirectly using co-existing minerals such as zircon and monazite that can be efficiently analysed using U-Pb age-dating, with their chemical compositions linked to garnet via inferred equilibrium elemental relationships.  The disadvantage of this approach is the age of garnet is inferred, rather than directly determined, and it can be difficult to prove garnet grew contemporaneously with the dated U-Pb minerals. In situ Lu-Hf laser ablation dating of garnet is a comparatively recent development that embodies the efficiency of LAICPMS U-Pb dating. Here, we explore the use of laser ablation garnet Lu-Hf dating to rapidly reveal the metamorphic history of polymetamorphic terranes, producing accurate dates (in excellent agreement with published ages) with precisions as low as 1.5%. For instance, garnets analysed from the Moine supergroup, NW Scotland produce ages that coincide with all major orogenic evets (e.g. ~950 Ma Renlandian Orogeny, 810 - 740 Ma Knoydartian orogeny, and 470 – 420 Ma Caledonian Orogeny). In certain cases, two of these orogenic events are preserved in a single garnet grain, and the high spatial resolution of the laser method allows to accurately resolve such multi-growth histories. In addition, we demonstrate that the laser ablation Lu-Hf technique has the potential to evaluate micron-scale isotopic disturbances (such as diffusion) in garnet.
Mitigating the effects of remanance in magnetic data processing and inversion
Authors: Jian Xiange , Liu Shuang
Published: February 2023

Natural remanance will distort the direction of the total magnetization of the magnetic source away from the direction of induction magnetization, which brings difficulties in magnetic data processing and susceptibility inversion. To solve the problem affected by remanance, a magnetic data processing and three-dimensional inversion strategy under remanance conditions is proposed: A method of the total magnetization direction estimation based on multiple correlations is proposed and applied to the processing of magnetic data, which can eliminate the influence of remanance and oblique magnetization. Moreover, the influence of remanance can be considered in the subsequent inversion of magnetic data. Adding the information on the direction of total magnetization into the inversion can more accurately depict the location of the underground magnetic source and recover the physical property distribution. This strategy is applied to the ground magnetic survey data of a mining area in Jiangsu, China. The effects of remanance and oblique magnetization on the processing and inversion of magnetic data are eliminated, and the physical properties and spatial distribution of underground magnetic bodies are restored, which provides geophysical evidence for the study of geological interpretation.
Mesospheric clouds in Jezero as observed by MEDA Radiation and Dust Sensor (RDS) at twilight
Authors: Toledo Daniel , Gomez Laura , Apéstigue Victor , Arruego Ignacio , Lemmon Mark , Smith Michael , Patel Priya , Munguira Asier , Sanchez-Lavega Agustin , Yela Margarita , Viudez-Moreiras Daniel , Martínez German , Vicente-Retortillo Alvaro , Newman Claire , de la Torre Juarez Manuel , Rodríguez-Manfredi Jose Antonio
Published: February 2023

Clouds on Mars are primary elements for understanding the past and present climate of the planet. Cloud particles can affect the energy balance of the planet, and so the atmospheric dynamic, as well as influence the vertical distribution of dust particles through dust scavenging. The dust scavenging by clouds has critical consequences in the water cycle of the planet; e.g. regions in the atmosphere with insufficient quantity of dust particles (or condensation nuclei) can inhibit the formation of H2O clouds and thus lead to the presence of water vapor in excess of saturation. The study of these interactions requires observations whose analysis allows us to infer simultaneously the properties of both the clouds and dust. To address these observations, the Radiation and Dust Sensor (RDS) is part of the Mars Environmental Dynamics Analyzer (MEDA) payload onboard of the Mars 2020 rover Perseverance.In this work we analysed the RDS observations made during twilight in the period Ls 39◦-262◦ to characterize the clouds above ∼ 30 km over the Perseverance rover site. From the ratio between the irradiance measured at zenith at 450 nm and 750 nm, we inferred that from Ls= 39◦ to 150◦ (referred as the cloudy period), water ice is the main constituent of the detected high-altitude aerosol layers. For Ls 150◦-262◦ dust is the main aerosol present. A total of 161 twilights were analysed in the cloudy period with a radiative transfer code in spherical geometry. Among other results we found: i) signatures of clouds or hazes on the RDS signals in the 58 % of the twilights; ii) most of the clouds were at altitudes between 40 km and 50 km and with particle sizes between 0.6 μm and 2 μm (in effective radius); iii) the cloud activity at sunrise is slightly higher that at sunset (65 % against 52 %), likely due to the differences in temperature; iv) the cloudiest time in Perseverance site and with the greatest cloud opacities is in Ls 120◦-150◦; and v) a notable decrease in the cloud activity around the aphelion (Ls ∼ 70◦), along with lower cloud altitudes and opacities. The drop in cloud activity around Ls ∼ 70◦ indicates lower concentrations of water vapor or cloud nuclei (dust) around this period in the Martian mesosphere. In this presentation, we will discuss the implications of our results on the water cycle of the planet.
Development of global ocean data assimilation system for weak coupling to the KIAPS atmospheric data assimilation system
Authors: Ko Eunbyeol , Clayton Adam , Jang Hyeyeong , Kwon In-Hyuk
Published: February 2023

KIAPS (Korea Institute of Atmospheric Prediction Systems) leads the development of NWP systems for the Korea Meteorological Administration (KMA), and developed the global atmosphere-surface NWP system that was made operational at KMA in April 2020. The system is based on a new atmospheric model called KIM (Korean Integrated Model), and incorporates a hybrid-4DEnVar system for deterministic analyses, and an LETKF for updating perturbations in the 50-member ensemble. During the next 4 years, KIAPS is aiming to develop this atmosphere-surface system into a full Earth system NWP system, to support skillful forecasts out to 30 days. KIM has been coupled with NEMO to provide the ocean component. Here, we report on our progress developing an ocean-only data assimilation for NEMO, configured for eventual use in a weakly-coupled atmosphere-ocean DA system. We focus on two aspects: (1) the impact of changing the surface forcing model from the Met Office Unified Model to KIM, and (2) the impact of reducing the ocean DA window from 24 to 6 hours, to match the atmospheric DA windows. This study will be preliminary results for the development of the coupled DA system.
Interannual Variability of Tidal Dynamics in the Tropical MLT
Authors: Yudin Valery , Goncharenko Larisa , Karol Svetlana , Lieberman Ruth , McInerney Joe , Pedatella Nicholas , Yudin Valery
Published: February 2023

The impact of the stratospheric Quasi-Biennial Oscillations (QBO) and Semi-Annual Oscillations (SAO) and physics of gravity waves (GW) on the dynamics and transport in the Mesosphere and Lower Thermosphere (MLT) has been examined in simulations of two Whole Atmosphere Models (WAM and WACCM-X) during the last decade. In the low-latitude MLT the year-to-year variations of the diurnal tide amplitudes and mean flow of whole atmosphere simulations constrained below 40 km by reanalysis data are in the good agreement with the observed interannual variability. The Mar-Apr diurnal tide amplitudes simulated by models display the observed enhancements (~50-100%) of amplitudes during the westerly QBO years. The observed influence of QBO and SAO on the tidal dynamics in the MLT is well captured by simulations that are capable to reproduce the global and regional tidal variability deduced from the space-borne and ground-based measurements of temperature and winds. Comparisons between simulations and observations, along with the model sensitivity studies highlight needs to quantify and constrain impact of mesoscale GW dynamics and physics in whole atmosphere predictions.
Understanding the impacts of inter-model difference in atmospheric CO2 concentration on terrestrial vegetation
Authors: Park Hee-Jeong , Yeh Sang-Wook
Published: February 2023

The increasing of atmospheric CO2 concentration due to human activities accelerates a warming rate and causes extreme climate events. The atmospheric-terrestrial biosphere carbon cycle is important for achieving the Paris agreement warming target and carbon neutrality with net zero emission. To understand the ecosystem carbon cycle, the Earth system model (ESM) is developed. However, there is a large inter-model uncertainty among ESMs thus reducing this uncertainty through understanding the relationship between atmospheric CO2 concentration and the terrestrial biosphere carbon cycle is important for reliable climate projection. Here, we investigate the impacts of inter-model differences in CO2 concentration over the East Asia on terrestrial carbon cycle using multi-ESMs. There is a larger uncertainty CO2 concentration in ESMs during historical period (1950-2014). To investigate impact of inter-model difference of CO2 concentration in ESMs on terrestrial vegetation in East Asia, we analyze emission-driven historical simulation in CMIP6 by classifying ESMs into two groups based on the averaged CO2 concentration in East Asia. The results show that inter-model difference of CO2 concentration in East Asia is associated with the carbon fertilization effect. ESMs with high CO2 concentration tend to simulate promoted vegetation activity. Furthermore, we analyze the relationship between CO2 concentration, terrestrial biosphere, and climate factors.
Evaluation of salt weathering equations. – a review
Authors: Oguchi Chiaki
Published: February 2023

Salt weathering of building stone is a major cause of loss of historic structures. Many geoheritage sites including stone heritage and geomorphosites have been damaged by this process. In nearly two centuries, research and observation relating salt weathering have accumulated. These studies could be organized focusing on theories, mechanisms, experimental methods, and research tools. This presentation introduce by reviewing many, though not enough, studies to summarize the research history of salt weathering, including the results of subsequent studies, especially focused on an important mechanism of salt weathering, crystallization pressure. Since the concept of crystallization was first proposed in the early 20th century, many equations have been proposed. However, in order to apply them correctly, it is important to consider the type of salt weathering and the surrounding environment, as well as the type and properties of salt and rock (rock properties), and to select and apply the proposed model according to the situation. Although salt weathering studies have been done in a wide variety of research fields, appropriate collaboration among disciplines will lead to meaningful conservation and will be used for practical problems in the future.