bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction and analysis of algal bloom trend in Yeongsan River using EFDC
Authors: Oh Hye Yeon , Lee Hye Won , Choi Jung Hyun
Published: February 2023

 Green algae, which is called water bloom, refers to a phenomenon in which cyanobacteria proliferate in large quantities and change the color of water to green. Algal bloom is one of the major water quality problems in freshwater ecosystems because it causes oxygen depletion in deep layer, oxygen supersaturation and toxicity in the surface layer, odor generation, fish death, and scum formation. Green algae are caused by hydraulic factors such as increased residence time due to the installation of hydraulic structures such as weirs, as well as physicochemical factors such as excessive influx of nutrients and rise in water temperature. One of Korea's four major rivers, the Yeongsan River, which originates in Damyang-gun, Jeollanam-do and flows into the West Sea, is experiencing water pollution problems, including algae, as the water quality and hydraulic environment change due to the construction and opening of weirs. Accordingly, Gwangju Metropolitan City, a large city where more than 80% of the population of the Yeongsan River basin resides, and Seungchon Weir, one of the two artificial weirs located in the Yeongsan River, were selected as the study area. In this study, the Environmental Fluid Dynamics Code (EFDC), a three-dimensional hydraulic and water quality dynamics model that can simulate various water quality indicators such as Chl-a, DO, T-N, and T-P, which was used to predict the trend of algal bloom in the study area.
Temporal variations of black carbon and nitro polycyclic aromatic hydrocarbons in Morelos, México
Authors: Mugica Violeta , Figueroa Jesús , Valle Brenda , Alvarez Tamara , Gutiérrez Mirella , Torres Miguel
Published: February 2023

Carbonaceous species such as nitro-polycyclic aromatic hydrocarbons (NPAHs) are toxic ubiquitous pollutants contained in the organic fraction of airborne particles, since several of them have mutagenic and carcinogenic properties. Black carbon has been recognized as a short live climatic pollutant which must be controlled in order to mitigate climatic change. Morelos is a little state of Mexico located at the South of the Metropolitan Area of Mexico City which has grown in the last years, but only few studies related with atmospheric pollution have been performed, then, with the aim to have better information related with carbonaceous compounds contained in the PM2.5 of the two main cities of Morelos, a monitoring campaign was carried out in Cuernavaca City, from 2016 to 2018, whereas in the Cuautla city the campaign was performed from 2017 to 2018. PM2.5 were collected with HighVol Tish equipment every six days. Elemental and organic carbon were analyzed with a Sunset Lab and toxic NPAHs were extracted with dichloromethane and sonication and further analyzed by gas chromatography–mass spectrometry (GC-MS). Median annual PM2.5 concentrations were 22.5 ± 7.2 mg m-3 and 19.6 ± 6.1 mg m-3, for Cuautla and Cuernavaca, respectively. Black carbon concentrations were higher in Cuautla than in Cuernavaca with 1.9 ± 0.5 mg m-3, and 1.3 ± 0.4 mg m-3 respectively, since Cuautla is a rural zone with frequent biomass burning The highest NHAPs concentrations were found in Cuautla with medians of 280.74 pg m-3, 90.67 pg/m-3 and 156.61 pg m-3, for the warm dry season (March-June), the rainy season (July-October) and the cold dry season (November-February) respectively. In Cuernavaca, the NHAPs presented lower concentrations in the three seasons with 116.41 pg m-3, 63.82 pg/m-3 and 128.99 pg m-3, respectively. 1-nitronaphtalene, 2-nitrophenentrene and 2-nitroanthracene were the most abundant compounds in both sites. Although PM2.5 Mexican Standard was not exceeded, the high concentrations of black carbon and NPAHs are of concern since black carbon is a climatic pollutant and some of the NHAPs compounds are carcinogenic.
Basic research on application of green dust suppression materials in mines
Authors: Wang Hetang , Zhang Qi
Published: February 2023

Dust suppressant is an important way to improve the efficiency of wet dust removal，but the dust suppressant currently used in mine is generally chemical dust suppressant，which faces challenging problems of low interfacial activity, high cost， poor degradation，as well as environmental pollution and other issues. To synthesis biological dust suppressant (BDS), a new idea of microbial fermentation technology is proposed. Response surface optimization method was used to explore optimal fermentation conditions. These results show that BDS can be produced to the maximum capacity under the conditions of temperature =37.56℃, pH =7.99, rotating speed =220 r/min, inoculant =2.17%, and liquid loading =59.89 ml.XRD, FTIR and HPLC-MS/MS were adopted to explore the structural features of BDS. Its molecular structure shows a cyclic lipopeptide. The wettability was tested with interface rheometer and we found its good wetting ability under the concentration of 0.06wt‰ compared with chemical dust suppressant. At the same time, dust reduction performance was studied with self-developed test system and BDS showed good performance in dust reduction efficiency. Its application prospects are broad, which may open a new situation for green and efficient control of mine dust.
Impacts of regional sea-level changes due to GRD effects on multi-centennial projections of Antarctic Ice Sheet under the ISMIP6-2300 experimental protocol
Authors: Han Holly , Hoffman Matt , Asay-Davis Xylar , Hillebrand Trevor , Perego Mauro
Published: February 2023

Evolution of ice sheets contribute to sea-level change globally by exchanging mass with the ocean, and regionally by causing the solid Earth deformation and perturbation of the Earth’s rotation and gravitational field, so-called “gravitational, rotational and deformational (GRD) effects”. In the last decade, much work has been done to establish the importance of coupling GRD effects particularly in modeling of marine-based ice sheets (e.g., West Antarctic Ice Sheet; WAIS) to capture the interactions between ice sheets, sea level and the solid Earth at the grounding lines. However, coupling of GRD effects has not yet been done widely within the ice-sheet modeling community; for example, GRD effects were not included in any of the ice sheet models that contributed to the most recent recent ice-sheet model intercomparison through 2100 (Ice Sheet Model Intercomparison Project for CMIP6: ISMIP6-2100; Serrousi et al., 2020) cited by the latest IPCC AR6 report.In this work, we couple the US Department of Energy’s MPAS-Albany Land Ice model (which was one of the models that participated in the ISMIP6-2100 project) to a 1D sea-level model and perform coupled simulations of Antarctica under the new ISMIP6-2300 protocol in which climate forcing is extended beyond 2100 to 2300. Comparing to the standalone ice-sheet simulations with fix bed topography without GRD effects, the results from our coupled simulations show multi-decadal to centennial-scale delays in the retreat of the Thwaites glacier in the West Antarctica. Our results further suggest that the strength of the negative feedback of sea-level changes on the WAIS retreat becomes weaker as the strength of the applied forcing increases, implying the pertinence of our commitment to limiting greenhouse gas emissions. In addition, within our coupled ice sheet-sea level modeling frame, we introduce a new workflow work in which the ISMIP6 protocol-provided ocean thermal forcing is re-extrapolated based on the updated ocean bathymetry. Our preliminary results indicate that bedrock uplift due to ice mass loss can block the bottom warm ocean, providing additional negative feedback, but also can block cold water when/if the vertical ocean temperature profile gets inverted due to climate change (e.g., as represented in the UKESM model - SSP585 scenario results).
Three-dimensional interpretation of DC resistivity/IP survey for Lithium exploration using high-precision topographic information from drone-mounted LIDAR.
Authors: Son Jeongsul , Kim Changryol , Bang Eunseok
Published: February 2023

Recently, due to the active spread of electric vehicles, the demand for batteries is increasing fast, and for this reason, the exploration for lithium that is an essential mineral for battery production, is increasing. In Korea, lithium exploration is also being conducted around deposits where lithium was identified in the past. However, most lithium mines are located in very rough terrain, so it is not easy to conduct a surface geological and geophysical exploration. Without considering complex topography, errors may occur in the inversion of surface geophysical exploration data, and in particular, it is necessary to use precise topographic information for the three-dimensional inversion. In this study, we would like to introduce a case study using high-resolution topographic data obtained from a drone-mounted LIDAR in the three-dimensional inversion of surface resistivity and IP data conducted for lithium exploration. The target area is the Boam Mine, located in the Middle East of Korea. Surface geophysical exploration was conducted along a road and ridge of the mountain, which are relatively easy to set up the survey line. Because existing topographic maps that are publically available did not include mining traces related to mining development and topographical changes formed by nearby roads, it is not adequate for the 3D inversion of surface resistivity and IP data. To acquire precise topographical information, aerial photography and LIDAR measurements using drones were performed. A numerical topographic model was constructed using the obtained high-precision DEM (digital elevation map). By applying this to the three-dimensional inversion, the distribution of the underground mineralization zone was estimated. The interpreted results were compared with the existing drilling results performed near the mine. Comparing the two results, drilling surveys using only surface geological information proceeded in the direction in which the mineralization zone did not develop. Drone LIDAR measurement is a costly exploration method and is difficult to use actively at all exploration sites. However, if three-dimensional inversion is required where the surface topography is very complex, as in this survey area, it could give more reliable inversion results.
The Alaska Peatland Experiment: two decades of hydrologic experiments show resilience in peatland CO2 respiration
Authors: Turetsky Merritt , Kane Evan , Euskirchen Eugenie , Dieleman Catherine , Rober Allison , Wyatt Kevin , Keller Jason , Cox William , Webb Hailey
Published: February 2023

Northern peatlands are experiencing some of the most rapid climate warming on the planet, which is compounded by increases in the extent and severity of climate-related disturbances such as drought, wildfire, and permafrost thaw.  Cumulatively these changes lead to both peatland wetting and drying at various scales. Since 2005, we have maintained large-scale flooding and drought experiments in an Alaskan rich fen. While peatland science is dominated by the paradigm that deep catotelm C is protected from mineralization by lack of O2 supply, our results show remarkable resilience or lack of sensitivity of ecosystem respiration to fluctuations in water table position. This presentation will outline the rationale and support for three hypotheses we are testing to explain this trend: 1) changes in food web dynamics between detrital and algal channels promotes resilience in peatland autotrophic respiration; 2) changes in plant species composition in response to wetting or drying, such as increases in sedge abundance affects soil redox pool recharge and ultimately controls the ratio of CO2 to methane production; and 3) humic substances contribute to the regeneration of electron acceptor pools via electron shuttling, leading to more sustained anaerobic respiration rates than previously described.  Support for these hypotheses are not mutually exclusive, and demonstrate that the influence of hydrologic changes on peatland carbon emissions will be mediated by complex vegetation and soil processes.
Anthropogenic Intensification of East Asia Summer Monsoon Frontal Precipitation System
Authors: Moon Suyeon , Utsumi Nobuyuki , Jeong Jee-Hoon , Yoon Jin-Ho , Wang S.-Y. Simon , Shiogama Hideo , Kim Hyungjun
Published: February 2023

Summer monsoon precipitation provides crucial water resources for agriculture, industry, and life in East Asia (EA). Meanwhile, it causes disasters when occurring over highly populated regions. Recently, we have witnessed a series of extreme precipitation events in South Korea, China, and Japan during the summer monsoon season. It remains uncertain whether these events and the EA summer monsoon precipitation system are affected by the ongoing climate changes. The summer precipitation in EA is contributed by various extra-tropical cyclones, fronts, and other weather systems. Here, we focus on the stationary front-induced precipitation, which accounts for more than 30% of EA summer precipitation. Based on objectively detected frontal systems, we found that the intensity of observed frontal rainfall increased by 19.8% during 1991–2015. It was further shown that the intensity increase of frontal rainfall is mainly attributed to anthropogenic greenhouse gas forcing on the basis of the Community Earth System Model Large Ensemble simulations. We found that the reinforced western North Pacific subtropical high makes enhanced water vapor convergence in the lower troposphere along its rim. This study confirms that the frontal summer monsoon precipitation system over EA has been intensified significantly by human-induced global warming, which will likely enhance further in the future.
Evaluation of the density distribution in bentonite-sand buffer blocks manufactured by floating die press method
Authors: Lee Deuk-Hwan , Yoon Seok , Lee Gi-Jun
Published: February 2023

For the safe disposal of high-level radioactive waste, several performances of the compacted buffer block are required, such as low hydraulic conductivity, high thermal conductivity, adequate swelling pressure, and good mechanical properties. Furthermore, it is well recognized as the performance of these buffers is highly correlated with the density of buffer blocks. Therefore, it is an essential task to fabricate the compacted buffer block with a homogenous density distribution. In this study, the manufacturing characteristics of bentonite-sand buffer were evaluated to identify the required density relationship in accordance with the pressure of floating die press and the homogeneity of the dry density distribution in the buffer blocks.
Data acquisition and processing of multi-frequency oscillatory hydraulic tomography in a granular aquifer
Authors: Nefzi Aymen , Paradis Daniel , Lefebvre René , Bour Olivier
Published: February 2023

Transport of solutes in aquifers is controlled by the heterogeneous spatial distribution of hydraulic properties, but the characterization of aquifer heterogeneity is quite challenging with conventional methods. Hydraulic tomography (HT) was developed to define the heterogeneous distribution of hydraulic conductivity (K) and specific storage (Ss). HT involves the emission of a series of hydraulic head perturbations in a stressed well and the recording of this signal at several levels in the stressed and observation wells. All recorded hydraulic head responses are simultaneously analyzed through numerical inversion, which provides the spatial distribution of hydraulic properties at a scale relevant for local site investigations.This communication reports on a tomographic experiment carried out in a heterogeneous and highly anisotropic granular aquifer at the Saint-Lambert research site near Quebec City, Canada. This site has already been the object of detailed characterizations with multiple hydraulic methods: pumping tests, packer slug tests, flowmeter profiles, vertical interference tests, and slug test tomography. A relatively new approach named oscillatory hydraulic tomography (OHT) was tested, in which multi-frequency oscillatory head perturbations are induced in an interval isolated by packers of the stressed well by a submerged rod that is electronically controlled by a winch system. Hydraulic responses are measured in the stressed intervals and in multiple intervals of an observation well.This study was primarily aimed at testing, first on an operational level, if the OHT signal could be generated in the stressed well and propagated to the observation well in a highly anisotropic granular aquifer. Second, the study developed a rigorous workflow for the treatment of the measured hydraulic heads. Third, in terms of characterization efficacy, the study aimed to determine if multiple controlled frequencies would allow the assessment of K spatial distribution.Results show that the field experiment provided clear measured hydraulic responses that could be used to obtain the 2D distribution of hydraulic properties from the inversion of OHT measurements. Comparison was made of inversion results using a single oscillatory frequency and multiple frequencies. Under conditions of realistic field measurement noise and uncertainty, it will be valuable in future work to compare the imaging capabilities of oscillatory hydraulic tomography against other tomographic methods. Further investigation is also needed to examine the information content of oscillatory hydraulic tomographic data for characterizing K and Ss heterogeneities through a sensitivity and resolution analysis. This study demonstrates the practical potential for the implementation of OHT experiments in relatively low permeability and highly anisotropic granular aquifers.
The Joint Effort for Data Assimilation Integration (JEDI): A unified data assimilation framework for Earth system prediction supported by NOAA, NASA, U.S. Navy, U.S. Air Force, and UK Met Office
Authors: Heinzeller Dom , Abdi-Oskouei Maryam , Herbener Stephen , Lingerfelt Eric , Trémolet Yannick , Auligné Tom
Published: February 2023

The Joint Effort for Data assimilation Integration (JEDI), is an innovative data assimilation system for Earth system prediction, spearheaded by the Joint Center for Satellite Data Assimilation (JCSDA) and slated for implementation in major operational modeling systems across the globe in the coming years. Funded as an inter-agency development by NOAA, NASA, the U.S. Navy and Air Force, and with contributions from the UK Met Office, JEDI must operate on a wide range of computing platforms. The recent move towards cloud computing systems puts portability, adaptability and performance across systems, from dedicated High Performance Computing systems to commercial clouds and workstations, in the critical path for the success of JEDI.JEDI is a highly complex application that relies on a large number of third-party software packages to build and run. These packages can include I/O libraries, workflow engines, Python modules for data manipulation and plotting, several ECMWF libraries for complex arithmetics and grid manipulations, and forecast models such as the Unified Forecast System (UFS), the Goddard Earth Observing System (GEOS), the Modular Ocean Model (MOM6), the Model for Prediction across Scales (MPAS), the Navy Environmental Prediction sysTem Utilizing the NUMA corE (NEPTUNE), and the Met Office Unified Model (UM).With more than 100 contributors and rapid code development it is critical to perform thorough automated testing, from basic unit tests to comprehensive end-to-end-tests. This presentation summarizes recent efforts to leverage cloud computing environments for research, development, and near real-time applications of JEDI, as well as for developing a Continuous Integration/Continuous Delivery (CI/CD) pipeline. These efforts rest on a newly developed software stack called spack-stack, a joint effort of JCSDA, the NOAA Environmental Modeling Center (EMC) and the U.S. Earth Prediction Innovation Center (EPIC). Automatic testing in JEDI is implemented with modern software development tools such as GitHub, Docker containers, various Amazon Web Services (AWS), and CodeCov for testing and evaluation of code performance. End-to-end testing is realized in JCSDA’s newly developed Skylab Earth system data assimilation application, which combines JEDI with the Research Repository for Data and Diagnostics (R2D2) and the Experiments and Workflow Orchestration Kit (EWOK), and which leverages the AWS Elastic Compute Cloud (EC2) for testing, research, development and production.
Large contributions of aged organic carbon to Arctic fjord sediments in Svalbard
Authors: Kim Dahae , Kim Jung-Hyun , Ahn Youngkyu , Jang Kwangchul , Jung Ji Young , Nam Seung-Il
Published: February 2023

Svalbard fjords are hotspots of organic carbon (OC) burial because of their high sedimentation rates. To identify sedimentary OC sources in Arctic fjords, we investigated surface sediments collected from eight Svalbard fjords using bulk and molecular geochemical parameters. All fjord surface sediments investigated were depleted in △14Corg (–666.9±240.3‰, n=28), suggesting that more recently fixed terrestrial and marine biomass is not the only contribution to the sedimentary OC. However, the source could not be determined by the most commonly used bulk indicators (i.e., Norg/TOC ratio and δ13Corg) in the Arctic realm. Thus, we applied a three-endmember model based on △14Corg and lignin phenols to disentangle the relative contributions of petrogenic, subglacial, and marine OC to the sedimentary OC pool. The fjord sediments (n=48) comprised on average of 79.3±26.1% petrogenic OC, 17.7±26.2% subglacial OC, and 3.0±2.5% marine OC. This three-end-member approach highlights the substantial contribution of petrogenic and subglacial OC to the present-day sedimentary OC in Svalbard fjords. Accordingly, under predicted warming worldwide, accelerated contributions of petrogenic and subglacial OC to fjords can be expected as a consequence of rapid glacier retreat, which may play an important role in the active carbon cycle as a potential CO2 source to the atmosphere.
The Unprecedented Pacific Northwest Heatwave of June 2021: Causes and Impacts
Authors: White Rachel , Anderson Sam , Booth James F. , Braich Ginni , Draeger Christina , Fei Cuiyi , Harley Christopher D. G. , Henderson Sarah B. , Jakob Matthias , Lau Carie-Ann , Mareshet Admasu Lualawi , Narinesingh Veeshan , Rodell Christopher , Roocroft Eliott , Weinberger Kate R. , West Greg
Published: February 2023

In late June 2021 a heatwave of unprecedented magnitude impacted the Pacific Northwest (PNW) region of Canada and the United States. Many locations broke all-time maximum temperature records by more than 5°C, and the Canadian national temperature record was broken by 4.6°C, with the highest recorded temperature 49.6°C. Local records were broken by large margins, even when compared to local records broken during the infamous heatwaves in Europe 2003, and Russian in 2010. A region of high pressure that became stationary over the region (an atmospheric block) was the dominant cause of this heatwave; however, trajectory analysis finds that upstream diabatic heating played a key role in the magnitude of the temperature anomalies. Weather forecasts provided advanced notice of the event, while sub-seasonal forecasts showed an increased likelihood of a heat extreme with 10-20 day lead times, with an increased likelihood of a blocking event seen in forecasts initialized 3 weeks prior to the heatwave peak. The impacts of this event were catastrophic. We provide a summary of some of these impacts, including estimates of hundreds of attributable deaths across the PNW, mass-mortalities of marine life, reduced crop and fruit yields, river flooding from rapid snow and glacier melt, and a substantial increase in wildfires—the latter contributing to devastating landslides in the months following. These impacts provide examples we can learn from, and a vivid depiction of how climate change can be so devastating.
Characterization of atmospheric methane release at hotspots in the outer Mackenzie River Delta
Authors: Wesley Daniel , Dallimore Scott , MacLeod Roger , Sachs Torsten , Risk Dave
Published: February 2023

Spatio-temporal patterns of methane (CH4) and carbon dioxide (CO2) release from natural sources needs to be better understood across the Arctic region. Climate change in the Arctic is occurring at a pace that may be 2 to 4 times the global average, and existing measurements derive from a limited number of field sites, and most originate during the growing season although important studies show that release continues during winter. The Mackenzie River Delta in the western Canadian Arctic holds thin and destabilizing permafrost, high organic content soils, a high proportion of wetlands, and vast natural gas occurrences at depth, all of which create high methane potential. In the present study, we conducted atmospheric CH4 and CO2 measurements using a mobile laboratory equipped with a greenhouse gas analyzer during the summer and winter. We also visited known aquatic and terrestrial CH4 flux hotspots, including pingos, lakes, river channels and wetlands, where we measured concentration transects and stable carbon isotope (13C-CH4) values to characterize CH4source and spatial pattern. Source stable carbon isotope (δ13C-CH4) signatures at hotspots ranged from -42 to -88 ‰ δ13C-CH4. Active surface microbial production was responsible for at least 4 of the 8 hotspots investigated, indicating that microbial production may be responsible for a greater number of CH4 hotspots than is indicated by previous studies in the region. Mobile surveys showed that shrubland, grassland and deep water were the most important ecosystems for CH4 and CO2 production during the wintertime and that low lying areas of the Delta had the highest atmospheric mixing ratios of CH4.
Estimation of the radiogenic heat production rate of fractured granitic rock mass based on in-situ natural gamma logging
Authors: Kim Myungsun , jo Yeonguk , Park In Hwa
Published: February 2023

Among many parameters needed to characterize subsurface rock mass related to underground storage and disposal projects, an important one is the heat production rate of the bedrock itself.The rock produces heat from the decay of radioactive isotopes consisting of minerals and its gamma-ray emissions, of which the magnitude is dominated by contents of major radioactive isotopes, e.g., uranium, thorium, and potassium. The heat production rate is generally calculated from the rock density and the radiogenic isotope contents, which can be measured from the spectrometry of drilled cores or rock fragments. However, such approaches are rarely available in deep boreholes because recovering rock samples from several hundred meters to a few kilometers is quite difficult.A recent geophysical logging technique for deep boreholes is available where the uranium, thorium, and potassium contents are measured from the gamma-ray spectrum. However, this technique requires the density to be measured separately, and the measurement depth of the equipment is still limited. As an alternative method, a natural gamma-ray logging tool was adopted to estimate briefly the heat production from the total gamma activity, which is relatively easy to measure. This study introduces the development of the proposed method for evaluating the heat production of a granitic rock mass with domestic commercial borehole logging tools, as well as its application and verifications in deep boreholes.
Making best use of atmosphere- and inventory-based approaches for quantifying and understanding emissions of greenhouse gases and ozone-depleting substances on a range of spatial scales.
Authors: Montzka Stephen , Hu Lei , DeCola Phil , Godwin Dave , Vimont Isaac , Croes Bart , Kuwayama Toshi , Dutton Geoff , Nance David , Hall Brad , Sweeney Colm , Andrews Arlyn
Published: February 2023

The likelihood for successful emission control and mitigation efforts of trace gases having adverse environmental effects can be enhanced by using a multi-faceted framework for quantifying and understanding emissions. While bottom-up activity-based inventories provide a quantification of various source sectors, appropriately designed atmosphere-based (top-down) approaches are able to independently evaluate the inventory and further refine temporal changes and spatial distributions.  Differences between bottom-up and top-down estimates are oftentimes observed and represent prime opportunities for increasing understanding and refining estimates of emissions.  Here we will present results derived from atmospheric observations made in the remote global atmosphere as well as from our North American measurement network.  The remote global observations enabled the identification of an apparent violation of the Montreal Protocol.  After our atmospheric measurements identified this unexpected issue, fairly quick resolution appears to have been achieved, in part due to the additional understanding of likely underlying causes provided by industry experts. Our North American measurement network also allows for trace-gas emission estimates on national and state scales.  Results from these efforts will be discussed, with an emphasis on describing how the interaction between inventory-derived and atmosphere-based information has led to an improved understanding of emission magnitudes along with identifying areas needing additional study.
Urban Growth of Houston, Texas over the Last Two Decades: Implications for Heat Stress
Authors: Nair Udaysankar , Blackford Andrew , Bonucchi Joey , Freitag Brian , Maskey Manil , Kaulfus Aaron
Published: February 2023

Houston is also one of the coastal cities in the US that has shown considerable growth in urban land cover over the last two decades. We utilized the National Land Cover Database derived from Landsat satellite imagery and coherent land products derived from NASA Moderate Resolution Imaging Spectroradiometer to analyze the urban growth of Houston. Our analysis shows an increase in the area of urban and builtup land cover in excess of 20% during this time period. We also constructed decadal averages of land surface temperature (LST) for the time periods 2000-2009 and 2010-2019. Spatial patterns of decadal average daytime LST show contiguous regions LST increase in the southwestern part of the city (increases of up to 3K). The region of anomalous LST also persists during nighttime, although with reduced amplitudes. We also utilized the Center for Disease Control (CDC)/Agency for Toxic Substances and Disease Registry (ATSDR) social vulnerability index (SVI) to categorize changes in decadal average LST and also MODIS-derived Normalized Difference Vegetation Index (NDVI) as a function of poverty. Our analysis shows that economically disadvantaged populations are subject to higher exposure to urban-enhanced heat stress and potentially, less access to green spaces.
Seasonal prediction and predictability of wind power potential over North America
Authors: Yang Xiaosong , Delworth Thomas , Jia Liwei , Johnson Nathaniel , Lu Feiyu , McHugh Colleen
Published: February 2023

The capacity factor (CF) is a critical indicator for quantifying wind turbine efficiency, and therefore has been widely used to measure the impact of interannual wind variability on wind energy production. Using the seasonal prediction products from GFDL’s Seamless System for Predicton and Earth System (SPEAR), we assess the seasonal prediction skill of CF over North America. SPEAR shows high skill in predicting winter CF over the western United States. The seasonal wind speed and CF variations associated with large-scale circulation anomalies are examined to understand the predictability mechanism of CF. The source of the skillful seasonal CF prediction can be attributed to year-to-year variations of ENSO and North Pacific Oscillation, which produce large-scale anomalous wind patterns over North America. The skillful seasonal prediction of CF is potentially beneficial to various stakeholders in the energy sector, including wind energy production, trading, and transmission.  
Widespread fracture movements during the 2019–2021 volcano-tectonic unrest on the Reykjanes Peninsula from TerraSAR-X interferometry
Authors: Ducrocq Cécile , Árnadóttir Thóra , Einarsson Páll , Jónsson Sigurjón , Drouin Vincent , Geirsson Halldór , Hjartardóttir Ásta Rut
Published: February 2023

Fractures and tectonic structures have been related to dyke emplacements, eruption location or dynamics in several volcanic areas around the world. Mapping of active faults is therefore key for assessing the potential tectonic and volcanic hazard within a region. The 2021 eruption in the Fagradalsfjall volcanic area (Reykjanes Peninsula, SW Iceland) was preceded by two years of volcanic unrest, including four non-eruptive unrests in the Svartsengi and Krýsuvík volcanic areas and a dyke intrusion in the Fagradalsfjall volcanic segment. Nine earthquakes of magnitudes M 5–5.6 were recorded during this time period and were widely felt by the surrounding population. Using interferometric synthetic aperture radar (InSAR) applied to TerraSAR-X data collected over 2019–2021, we mapped fracture movements over the Reykjanes Peninsula. We identified ~1250 active structures across 54 interferograms during this time period, complementing previously mapped structures. Our study reveals extensive fracture movements across most of the Peninsula, extending from Reykjanes to NE Krýsuvík volcanic areas. We particularly highlight previously undetected structures beneath the town of Grindavík as well as a N45°E striking structure in the Fagradalsfjall volcanic area, active during summer-autumn 2020, prior to the 2021 dyke intrusion. We propose that this structure influenced the location of the longest lasting vent of the 2021 eruption. The observations presented in this study have important implications for improving our understanding of volcano-tectonic interactions and hazard assessments in Iceland and worldwide.
Direct radiative effects of black carbon and brown carbon from Southeast Asia biomass burning with the WRF-CMAQ two-way coupled model
Authors: Huang Yeqi , Lu Xingcheng , Li Zhenning , Fung Jimmy , Wong David
Published: February 2023

Black carbon (BC) and brown carbon (BrC) have been considered light-absorbing components of particulate matter and affect weather and climate. Biomass burning (BB) emission from Southeast Asia (SEA) is a key source of BC and BrC on the planet. In this study, the Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) two-way coupled model was used with the Global Fire Emissions Database Version 4, to investigate the direct radiative effect (DRE) of BC and BrC in March 2015 over SEA. The Rapid Radiative Transfer Model for the Global Circulation Model was employed in the WRF-CAMQ to calculate the aerosol optical properties in 14 shortwave spectral bands. Parameterization of the light absorption property of BrC described by Saleh et al. (2014) is coded and embedded into the WRF-CMAQ. The light absorption property of BrC is determined by the BB BC to organic carbon ratio in each grid and each time step, which is more in line with the smog chamber experiments compared to the originally fixed coefficient in the model. Experiments with and without BC/BrC DRE were conducted. Preliminary results show that the monthly mean DRE from BB BC can reach 18.3 W/m2 in the Indochina region and 3.0 W/m2 in southern China, decreasing the surface temperature by up to 0.2 and 0.1 °C, respectively. The monthly DRE from BB BrC can reach 1.3 W/m2 in the Indochina region but only around 0.1 W/m2 in southern China. Meanwhile, the maximum instant DRE of BrC can reach 10.0 W/m2, which is expected to exert a local synoptic scale influence.
Statistics of the high-speed electron flows in the magnetotail
Authors: Liu Huijie , Li Wenya , Tang Binbin , Norgren Cecilia , Graham Daniel , Khotyaintsev Yuri , Gershman Daniel , Burch James , Wang Chi
Published: February 2023

High-speed electron flows play an important role in the energy dissipation and conversion in the terrestrial magnetosphere and are widely observed in regions related to magnetic reconnection, e.g., the vicinity of electron diffusion regions (EDRs), and separatrix layers. NASA’s Magnetospheric Multiscale mission was designed to resolve the electron-scale kinetic processes of Earth’s magnetosphere. Here, we perform a systematic survey of high-speed electron flows in the terrestrial magnetotail using the MMS observations from 2017 to 2021. The high-speed electron flows are characterized by electron bulk speeds larger than 5000 km/s. We identified 649 events. Those events demonstrate unambiguous dawn-dusk asymmetry, and 73% of them locate in the dusk magnetotail. The selected events are found in EDRs, the reconnection separatrix boundary layer, and the lobe region. More than 70% of the events are identified in the separatrix boundary layer and the lobe region and are aligned with the ambient magnetic field. 75 cases, with magnetic field magnitude smaller than 5 nT, locate near the plasma-sheet neutral line. Approximately 20 cases among them have EDR signatures, and those high-speed electron flows are directed arbitrarily with respect to the ambient magnetic field. We also show other statistical properties of the events, including electron bulk speed, electron number density, and temperature anisotropy. 
Optimal Operation Rules for Parallel Reservoir Systems with Distributed Water Demands
Authors: Meng weisa , Wan wenhua , Zhao jianshi , Wang zhongjing
Published: February 2023

This paper addresses the doubts regarding the spatial characteristics of the commonly used rules for parallel reservoir system operation. The rules based on aggregation-decomposition determine the system total release first and then assign this release to individual reservoirs, without considering the water demand distribution in the river network. In this paper, a conceptual model for parallel reservoir systems with distributed water demands is proposed. Three specific optimality conditions are derived for determining the optimal analytical solution. A rigorous proof shows that the aggregation-decomposition-based rules are a special case of the derived rules. An efficient algorithm is then developed based on the optimality conditions and shortage allocation index (SAI), in which a larger SAI indicates taking a higher percentage of the system water shortage, as release or storage. Unlike traditional algorithms that modify the violated variables empirically, we propose a criterion in terms of relative deviation indicators to determine the crucial priority of variable modification. This criterion can effectively address constraint violations. The optimal rules along with the solution algorithm are then demonstrated by the operation of a parallel reservoir system in the Shiyang River Basin, China. The results show that the proposed rules and algorithm are more efficient and effective than traditional algorithms and aggregation-decomposition-based rules, especially in dry seasons with more binding constraints.
Isotopic exploration of eco-hydrological connectivity in the riparian zones of Southern Western Ghats, India
Authors: Puthalath Saranya , Krishnan Sreelash , Thulaseedharan Akhil , Rahman Abdur , Laskar Amzad , Kumar Sanjeev
Published: February 2023

Understanding the route of precipitation through the soil-vegetation-atmosphere continuum is significant for partitioning evapo-transpiration (ET) into its components. The δ18O of water has been used in the present study to understand the eco-hydrological connectivity in the tropical humid Western Ghats, India. We conducted spatially distributed sampling of stream water, xylem, groundwater, root, and soil pore water. The results suggest that the vegetation mostly accessed water from the intermediate soil layer and not from the streams. Though the shallow roots exhibited enriched isotopic signatures due to the availability of evaporated soil water, the xylem water exhibited rather depleted signatures suggesting that the dominant uptake happened from the layers beneath the topsoil. While a significant Isotopic elevation effect (-0.09/100 m elevation) was observed in the stream water, the xylem water elevation effect was not significant. The major discontinuity of the Western Ghats, the Palghat Gap, exhibited the circulation of 18O enriched water in the soil-vegetation-atmosphere continuum due to the evaporative enrichment of source water and the subsequent abstraction by trees. The calculated leaf water enrichment at the evaporative site of the leaf (∆Le) and the ET fluxes recorded in the weighing lysimeters as well pointed towards the isotopic enrichment in the Palghat Gap. Additionally, the lysimeter ET flux and the mixing model-based partitioning of ET show the transpiration component to be 88%.
Glacial lake outburst debris flows in the Himalayas in response to climate change
Authors: Zou Qiang , Zhou Bin , Chen Siyu , Zhou Wentao , Jiang Hu , Yao Hongkun
Published: February 2023

Global warming has led to environmental changes in the alpine Himalayan mountains, with significant glacier retreat, an increase in the area and number of glacial lakes, and an increase in the frequency and scale of glacial lake outburst debris flows, causing significant damage to people and facilities in downstream. In this study, we analyzed the spatial heterogeneity and variations of disaster-forming environments on the north and south areas of the Himalayan, identified the distribution patterns of glacial lake outburst debris flows, and predicted debris flows’ changing trends in the Himalayas. The results demonstrate that the distribution and variations of glaciers and glacial lakes in the Himalayan region have apparent spatial heterogeneity. The Central and South Himalayas are where glaciers and glacial lakes undergo the most dramatic changes. Glacial lakes are widely distributed in the Central Himalayas and southern slopes, with an increase in area and number from 1990-2015. New glacial lakes at higher elevations and alterations in moraine lakes dominate glacial lake variations across the region. Since the 20th century, there have been 249 outbursts of 113 glacial lakes in the Himalayan, Karakorum, and Southeast Tibetan regions, with the majority of outbreaks occurring in the Central and Eastern Himalayas along steep sections of main rivers. In the period 1901-2019, the inflection point for glacial lake outburst hazard is 1966+37/-31 years (median and 95% HDI), and the frequency of glacial lake outbursts proliferates before the inflection point and slowly increases after the break-point; the annual mean temperature changes have opposite trends before and after the inflection point, reflecting the lag effect of glacial lake outbursts on temperature changes. In addition, the measured data were calibrated and down-scaled the future simulated climate prediction data to reveal the spatial and temporal trends of glacial lake outburst debris flow disaster risk under the influence of future climate-causing factors. The annual mean temperature and precipitation in the Himalayas generally exhibited an upward trend in the 21st century, with higher increment speeds of warming and humidification on the northern slopes; Increasing very high and high glacial lake outburst debris flow hazard zones are a consequence of climate change, with a more concentrated distribution in the centre and northwest of the Himalayan Mountains.
Ionospheric indices GIX and SIDX for the regional characterization of ionospheric perturbations degree
Authors: Cahuasquí Juan Andrés , Nykiel Grzegorz , Hoque Mainul , Jakowski Norbert
Published: February 2023

The total electron content (TEC) measured along different satellite-receiver links is strongly sensitive to severe spatial gradients and rapid changes in the ionosphere. Therefore, key information on space weather conditions and, in particular, on the perturbation degree of the ionosphere is crucial to assure stable and reliable services using Global Navigation Satellite Systems (GNSS) signals. By using dual-frequency GNSS measurements, the German Aerospace Center has developed the Gradient Ionospheric indeX (GIX) and the Sudden Ionospheric Disturbance indeX (SIDX) as proxies capable of estimating spatial and temporal perturbations degree of the ionosphere instantaneously, without the necessity to include historical data in the analysis.In this talk, we present our advances for characterizing spatial and temporal ionospheric perturbations by utilizing GIX and SIDX in the framework of the Coordinated Ionospheric Study of Scales and Indices (CISSI) initiative, within the scientific activities of the Committee on Space Research (COSPAR). Namely, we report on the outcomes achieved with these approaches when applying them to GNSS datasets acquired over Europe and South America during a stormy and a quiet period of geomagnetic activity in 2015 (Day of Year 75-78 and 142-145, respectively). Moreover, we examine the scientific potential of these ionospheric perturbation indices at different GNSS configurations, latitudinal zones and distance ranges, and discuss their applicability in space weather services.
Dynamical downscaling of ERA5-based high-resolution streamflow dataset over the Geum River basin, South Korea via VIC-river routing model (1950-2021)
Authors: Kim Byeong-Hee , Kam Jonghun
Published: February 2023

The Geum River basin, located in the west-central part of the Korean Peninsula, is the third largest and minimally human-disturbed river basin in South Korea. Streamflow and available water resources from this basin is critical for water supply for agriculture. Due to the increased population, industrialization, and climate change, changes in streamflow and available water resources for the Geum River are expected. However, there are limitations in analyzing water resource changes in the Geum River Basin with discontinuous and relatively short observational streamflow records.In this study, we propose to dynamically downscale daily surface and base runoff data from the 10-km ERA5 reanalysis product via VIC-River Routing model. The VIC-River Routing model was ran at the 90-meter spatial resolution with geographical information to reconstruct long-term naturalized streamflow data over 1950-2021. In the VIC-River Routing model, the flow direction, stream order, and slope estimated from the 90-meter digital elevation model (DEM) over Geum River basin as the topographical parameters. This downscaled natural streamflow data will provide an opportunity to investigate hydroclimatic changes of the hydrologic regime of Geum River.
Evaluation of the sub-seasonal forecasting skill of SubX models for precipitation during recent multi-year droughts over the Korean Peninsula
Authors: Park Chang-Kyun , Kam Jonghun
Published: February 2023

Daily to monthly variations of precipitation directly affect the propagation of an emerging drought. To cope with adverse impacts, a skillful sub-seasonal forecast of precipitation is essential to track the evolution of the emerging drought and provide actionable information for stakeholder and water resources managers. This study evaluates the predictive performances of the Subseasonal Experiment (SubX) models (ECCC-GEPS6, EMC-GEFSv12, ESRL-FIMr1p1, GMAO-GEOS_V2p1, and RSMAS-CCSM4) for the precipitation variations during two recent long-term drought events (2007−2010 and 2013−2016) over the Korean Peninsula. Sub-seasonal prediction skill of SubX models are quantitatively evaluated via multiple verification metrics for ensemble, deterministic, and categorical forecasts. Results show that during the emergence of multi-year droughts, the intensification and persistence of drought severity are generally better predicted by SubX models than the weakening and recovery of the drought severity in all forecast times (1−4 weeks). The multi-model ensemble approach shows the best prediction skill, and EMC-GEFSv12 which has the most ensemble member presents the better predictive performance than other models. In addition, results from the sensitivity test to ensemble member size show that multiple ensemble member can enhance the prediction skills significantly up to eight ensemble members. Overall results suggest that the forecast of SubX on multi-year Korean Peninsula droughts can provide actionable information that helps manage water resources in a timely manner.