bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical study on plasma velocities in bottom-side ionosphere over low latitude Hainan station: Digisonde measurement
Authors: Wang Guojun , Shi Jiankui , Wang Zheng , Cheng Zhengwei , Wang Xiao , Shang Sheping
Published: February 2023

In this paper, the data measured with Digisonde at the low-latitude Hainan station from 2003 to 2016 are statistically analyzed to specify the diurnal average variations of the bottom-side F region ionospheric plasma velocity vector V. This is the first comprehensive analysis of Digisonde measurements of low latitude F region plasma velocities in the East Asian sector that use a database covering more than one solar cycle. The vector components VN, VE, and VZ are analyzed for two levels of solar flux and two levels of geomagnetic activity, respectively. The diurnal variations of the average VZ show three positive peaks near the prereversal enhancement (PRE) period, pre-midnight, and before sunrise, respectively, and a prominent valley in the early morning. The averaged VZ significantly increased with solar flux in the period of PRE during equinoxes, but it was only slightly affected by Kp. The VE component was westward in daytime and eastward in nighttime. The average eastward VE increased significantly with solar flux but decreased with Kp, whereas the average westward VE exhibited only a small variation with solar flux and Kp. The average VN was almost southward independent of solar flux and Kp. The plasma velocities over the Hainan station were mainly caused by the electric field and neutral wind. Our results show that the features of the vertical and meridional velocities over the Hainan station in the morning associated with the formation of the equatorial ionization anomaly (EIA).
Analysis of the Effect of Jupiter's Northern Aurora on Juno Microwave Radiometer Observations
Authors: Oyafuso Fabiano A. , Levin Steven , Waite Jack Hunter , Steffes Paul , Bolton Scott
Published: February 2023

Juno's Microwave Radiometer (MWR) is intended to measure Jupiter's thermal emission using six channels that effectively probe different depths of Jupiter’s atmosphere [Li et al. 2017 Geophys. Res. Lett. 44, 531].  However, MWR has also observed non-thermal effects such as lightning [Brown et al. 2018 Nature 558, 7708], synchrotron emission [Levin et al AGU 2022], and reflections due to aurorae [Hodges et al EGU 2022].  Each effect diminishes with increasing channel (i.e. frequency) and is usually significant only in the two or three longest wavelength channels.  In this work we characterize the impact of the northern aurora on measured MWR intensities.  Near the poles significant reductions (up to a few hundred K) in intensities from those expected from Jupiter's thermal emission are found in every orbit in the two longest wavelength channels (~50cm and ~24cm) and for some orbits can be identified at wavelengths as short as 6cm.  They are shown to correlate well with regions poleward of the location of the mean auroral oval measured by Juno's Ultraviolet Imaging Spectrometer (UVS).  Intriguingly, several orbits demonstrate sudden changes in brightness temperatures that vary on timescales of one to two spins of the spacecraft.  These variations are suggestive of a transient phenomenon (on the order of a minute or less) that is coherent on a length scale comparable to a significant fraction of the size of MWR's polar footprints (~0.1 RJ). We will present an analysis of this effect in the MWR data and compare with measurements from UVS and with field and particle measurements of temporal and spatial variations to assess the physical connections between the changes in microwave emissions and auroral processes.
Monitoring Glacial Lakes in High Mountain Asia from 2008 to 2
Authors: Zhang Meimei , Chen Fang
Published: February 2023

Glacial lake outburst floods (GLOFs) are among the most serious natural hazards in mountainous regions in the last several decades. The recent global warming has caused dramatic glacial lake changes and increased potential GLOF risk, particularly in High Mountain Asia (HMA) region. Thus, there is a pressing need to detect and monitor lake area changes and spatial distribution of glacial lakes in this region. In this research, we produce more accurate and complete maps of glacial lake extent in the HMA in 2008, 2012 and 2016 with consistent time intervals using Landsat satellite images and the Google Earth Engine (GEE) cloud computing platform, and further study the formation, distribution and dynamics of the glacial lakes. In total 17016 and 21249 glacial lakes were detected in 2008 and 2016, respectively, covering an area of 1420.15±232.76 km2 and 1577.38±288.82 km2; the lakes were mainly located at altitudes between 4400 m and 5600 m. The annual areal expansion rate was approximately 1.38 % from 2008 to 2016. To explore the cause of the rapid expansion of individual glacial lake, we investigate their long-term expansion rates by measuring changes in shoreline positions. The results show that glacial lakes are expanding rapidly in areas close to glaciers, had a high expansion rate of larger than 20 m/yr from 2008 to 2016. Glacial lakes in the Himalayas show the highest expansion rate of more than 2m/yr, followed by the Karakoram Mountains (1.61 m/yr) and the Tianshan Mountains (1.52 m/yr). The accelerating rate of glacier ice and snow melting caused by global warming is the primary contributor to glacial lake growth. These results may provide information that will help in the understanding of lake detailed dynamics and the mechanism, and also facilitate the scientific recognition of the potential hazards associated with glacial lakes.
Turbulent Dissipation in the Boundary Layer of Precession Driven Flow in a Sphere
Authors: Shih Sheng-An , Triana Santiago Andrés , Dehant Véronique
Published: February 2023

The energy dissipation in the fluid flow near the boundary separating the core and the mantle (i.e. the CMB) of a planet or moon with a fluid interior is a crucial parameter to understand its rotational dynamics. This boundary layer is typically very small compared to the core radius, and can become turbulent under certain conditions, which presents a challenge for global scale simulations of the flow in the fluid core. Here we construct a local Cartesian model to study the boundary layer of a precessing planet or moon. The solutions we derive in the laminar regime, i.e. where the Reynolds number Re is small and the non-linear term is neglected, are consistent with previous studies. This gives us confidence to push the model further into the turbulent regime. We solve numerically the governing equations, i.e., the Navier-Stokes equation and the continuity equation for an incompressible fluid in a rotating frame. We observe that, when the flow is turbulent, the boundary layer dissipation is increased, compared to its laminar counterpart, as expected. Moreover, we found that the velocity profile agrees with the law of the wall, a theory developed to study turbulent flow near a solid boundary. Based on our numerical results, we further construct a turbulence model using similarity theory. Last but not least, due to chemical interaction on the planetary core-mantle boundary, small-scale topography or surface roughness might exist. To investigate this topographic effect, we impose a sinusoidal topography in our local model. Preliminary results show further increase of the dissipation. Our results may provide valuable insight into the boundary layer dissipation near the CMB for both the Earth and the moon.
Observing Multidecadal Changes in Coastal Topography of Svalbard from Satellite Images
Authors: Tseng Kuo-Hsin , Giletycz Slawomir Jack , Liu Chien-Liang , Hsu Hsiao-Jou , Chuang Shu-Ping
Published: February 2023

The warming in the Arctic has induced accelerated changes in coastal topography, such as the retreat of glaciers, thaw of permafrost, and increase of erosion and sedimentation along the coastline. A majority of Svalbard territory has been designated as natural reserves for numerous wildlife, especially on the west coast of Spitsbergen, which has seven locations listed as Ramsar Sites. Therefore, monitoring coastal dynamics is crucial for assessments of the climatic impact on those habitats. This study aims to utilize multiple satellite data, including Sentinel-1, Sentinel-2, and Landsat series to reconstruct time-varying digital elevation models (DEMs) over the intertidal zone of west Spitsbergen. The method includes the following steps: (1) classifying water in an image; (2) stacking images for inundation frequency; (3) converting frequency to elevation via a tide model; (4) repeating the workflow in a five-year temporal window. The latest DEM is verified by ICESat-2 spaceborne LiDAR ATL03 photons. Our preliminary results show that the accuracy of DEM, in terms of standard deviation, achieves 0.5 m level. Slight changes in coastal topography have been observed near Longyearbyen and other outlet glaciers.
Study on the mineralization age of the Akenobe Sn-Cu-W polymetallic deposit in southwest Japan
Authors: Ogasawara Mitsuki , Ohta Junichiro , Ishida Mizuki , Nakamura Kentaro , Yasukawa Kazutaka , Kato Yasuhiro
Published: February 2023

The northern part of Hyogo Prefecture in the southwestern Japan is a unique area having a number of large deposits that had produced various metals of industrial importance. For instance, the Nakaze deposit had been known for its extremely high-grade gold ore. The Ikuno deposit had been one of the major silver mines in Japan. Among them, the Akenobe deposit produced large amounts of tin, copper, zinc, and tungsten, as well as indium which is critical for electronic devices. The mineralization age of the deposit is a key constraint to discuss the ore genesis of such a polymetallic mineralization zone constituting large deposits of industrially important metals. However, the age of the Akenobe deposit was estimated only from the related igneous rocks by K-Ar dating, whereas a direct age determination of the metal veins has not been conducted yet. Here, we aim to directly determine the mineralization age of the veins by rhenium (Re)-osmium (Os) dating method. To apply the Re-Os dating to the veins of Akenobe mine, it is necessary to figure out the distribution of Re and Os within the ore samples. Therefore, we conducted Re-Os mapping by a Laser Ablation (LA)-Multi-Collector (MC)-ICP-MS at Ocean Resources Research Center for Next Generation, Chiba Institute of Technology. This instrument can detect extremely-low-concentrations of Re and Os simultaneously by using multiple ion-counting detectors equipped with discrete dynode type secondary electron multipliers. In the presentation, we will report the results of the Re-Os mapping using LA-MC-ICP-MS and mineralogical observation of the Akenobe ore samples, and discuss implications for the mineralization age in the Akenobe deposit.
Will Taiwan lose its lagoon? Effects of sandbar migration and sediment transport on lagoon siltation in Southwest Taiwan
Authors: Dhian Benedict Andrew , Wang Hsiao-Wen
Published: February 2023

Cigu lagoon in Southwest Taiwan is susceptible to disappear due to sandbar migration and sedimentation issues over the past few decades. According to the Water Resources Agency in Taiwan, the sandbar has retreated more than 800 meters to the landward from 1975 to 2005. As a result, the Cigu lagoon has been shrinking from 10,000 to 1,350 hectares nowadays. In addition, various river and coastal management decisions in the last century have also contributed to the disruption of the natural sediment balance along the Cigu coast. A compounding consequence of these processes continuously occurs, changing the hydrodynamic characteristics and accelerating the siltation process of the lagoon.A deeper understanding of the erosive and deposition processes at play in the Cigu lagoon is essential to inform current coastal management practices in the area. This study combined remote sensing and a 2-D hydrodynamic model to examine the sediment transport and siltation process in the Cigu lagoon. A remote sensing technique is conducted to complement the initial suspended sediment concentration (SSC) on the model. The results of this study indicate that tidal currents and wave forcings primarily influence the sediment transport and siltation process of the Cigu lagoon. The annual siltation of the Cigu lagoon is 0.82 cm, and this process mainly occurs during the winter season. The strong winter wave induces sediment mixing and suspension in the water column, which causes the SSC and sedimentation of Cigu higher than those in the summer.In this particular case, lagoon siltation was also exacerbated by sediment from the sandbar. The overwash phenomenon swept a large amount of sediment from the sandbar to the lagoon. Moreover, based on our sediment budget analysis, about 0.1 million m3 of sediment in the Cigu sandbar is eroded every year, and some sediment is transported to the lagoon by tidal currents and wave actions. The study implies that many elements have contributed to the siltation of Cigu lagoon, and the whole coastal system management needs to be taken into consideration for managing lagoon siltation.
Hydrometeorological processes and controls of the upper-tail floods over China
Authors: Yang Long
Published: February 2023

Characterizing the upper tail of flood peak distributions remains a challenge due to the elusive nature of extreme floods, particularly the key elements of flood-producing storms that are responsible for them. Here I examine the upper tail of flood peaks over China based on a comprehensive flood dataset that integrates systematic observations from 1759 stream gaging stations and 14,779 historical flood surveys. I show that flood peak distributions over China are associated with a mixture of rainfall-generation processes. The storms responsible for the upper-tail floods (with the recurrence intervals beyond 50 years) are characterized with anomalous moisture transport and/or synoptic configurations, with respect to those responsible for annual flood peaks. Anomalous moisture transport (in terms of intensity, pathways, and durations) dictates the space-time rainfall dynamics (relative to the drainage networks) that subsequently lead to anomalous basin-scale flood response. I provide physical insights into extreme flood processes based on downscaling simulations using the Weather Research and Forecasting model driven by the 20th Century Reanalysis fields. Modeling analyses for a collective of extreme flood events highlight the role of interactions between complex terrain and large-scale environment in determining the spatial and temporal variability of extreme rainfall. My analyses contribute to improved understanding of the unprecedented flood hazards over China by establishing the nexus between atmospheric processes and basin-scale flood response. These knowledge gains can be potentially used to the upper tail of flood peak distributions.
The spectrally and vertically decomposed outgoing longwave radiation and its climate trends in the far-infrared
Authors: Huang Han , Huang Yi
Published: February 2023

The outgoing longwave radiation (OLR) at the top of the atmosphere is a critical component of the Earth's radiation energy budget. A substantial portion of the OLR energy lies in the far-infrared (FIR) spectrum, which has not been directly measured for understanding weather and climate variations. Several satellite projects under development, including the Thin Ice Cloud in Far Infrared Experiment (TICFIRE, Blanchet et al. 2011) funded by the Canadian Space Agency, the Polar Radiant Energy in the Far Infrared Experiment (PREFIRE, L’Ecuyer et al., 2021) of U.S. NASA, and the Far-Infrared Outgoing Radiation Understanding and Monitoring (FORUM, Palchetti et al., 2020) of the European Space Agency, are being developed to fill this observation gap. Given that the FIR observation data is not available yet, we use simulations to acquire prior knowledge of the climatological mean distribution of the OLR in FIR, by using a rapid radiative transfer model, RRTMG, to simulate spectrally decomposed OLR in different spectral bands from global instantaneous atmospheric profiles of the fifth generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis (ERA5). Based on the radiative transfer equation, we dissect the OLR by attributing its distribution and variation to spectrally and vertically decomposed contributions of the atmosphere and Earth surface. Our results disclose that the relatively higher far-infrared fraction of the OLR in polar region is due to stronger surface contribution and identify a minimum atmospheric contribution layer around the tropopause. On the other hand, the variability of the spectrally decomposed OLR field is dissected with the aid of a new set of radiative sensitivity kernels. This analysis discovers that the non-cloud longwave climate feedback, as well as its inter-climate model discrepancy, mainly results from the upper tropospheric thermodynamic fields (temperature and water vapor) and their effects on the FIR radiation.
Seismogenic Thickness of the Andean Crust
Authors: Riedel Martin , Tassara Andrés , Cabello Catalina , Leal Denisse , Castillo Mauro
Published: February 2023

The thickness of the seismogenic crust (Ts) controls the location and magnitude of crustal earthquakes. Its upper limit is generally found near the surface and correlates to crustal seismicity onset depth (SOD) while its base correlates to the brittle-ductile transition in the crust and the seismicity cutoff depth (SCD) (Chiarabba & De Gori, 2016; Wu et al., 2017 and Zuza & Cao, 2020). Thus, it is a proxy of the brittle crust thickness and limits how deep earthquake ruptures may propagate, influencing their magnitude. Furthermore, crust with a thin Ts is inherently weaker and may concentrate more earthquakes (Burov, 2010 and Zuza & Cao, 2020). Given these factors, knowledge of Ts can help constrain future earthquake’s locations and magnitudes, aiding in seismic hazard assessment and mitigation.Previous authors have used seismic data to calculate Ts in Italy, California and Taiwan considering the depth distribution of earthquakes (eg., Chiarabba & De Gori; 2016, Wu et al., 2017 and Zuza & Cao, 2020). However, the Chilean case presents a special and complex scenario. Here, the Nazca plate subducts below the South American plate producing an abundance of subduction earthquakes. Comparatively, crustal seismicity is sparse which presents a challenge. Adding to the complexity of the problem, the geometry of subduction as well as crustal thickness change considerably in latitude and longitude.In this work, we present the first attempt at a Ts map of Chile. Following the methodologies of Chiarabba & De Gori, 2016; Wu et al., 2017 and Zuza & Cao, 2020 we divided the study area (ie. the Chilean margin between 15º and 45ºS) into a grid of square cells superposed by 2/3 of their width and calculated the depth distribution of earthquakes in each cell. As no consensus on which depth percentile to use for SOD and SCD exists, we calculated the percentiles 1, 5 and 10 for SOD and 90, 95 and 99 for SCD. Ts was then calculated as the difference between SCD and SOD. We compared the different outcomes.Furthermore, we test a new methodology, relaying on cells of variable radius. Here, cell size changes according to earthquake density. We believe this approach is optimal for heterogenous catalogues, such as is the case in Chile.Our results indicate that Ts in Chile varies latitudinally and longitudinally. Longitudinally it is generally thin at or close to the subduction trench, becomes thicker towards the east, reaching a maximum thickness below the central valley and then becomes thinner once again towards the volcanic arc. Latitudinally, it varies with crustal thickness as well as with subduction geometry (ie. it is thicker above the flat slab region).
Correlations of the seismic activity monitored in three subduction zones belonging to Cocos plate by using the visibility graph method.
Authors: Ramírez-Rojas Alejandro , Flores-Márquez Elsa Leticia
Published: February 2023

The temporal sequences of magnitudes recorded in seismic active zones exhibit complex behavior which is associated with the wide diversity of scales of fractures sizes when an earthquake on the Earth’s crust occurs. Earthquakes can be considered to be nearly, or even critical phenomena exhibiting dynamic phase transitions, where a mainshock is the beginning of a new phase. Near the critical point is where phase transition (order-disorder) occurs, and scaling laws with long-range order correlations are produced, so that the complexity of seismicity allows earthquakes to be characterized by a more diverse and riche phenomenology. In the last years, the ideas linked to nonlinear time series analysis and complex network theory have been related. Among those ideas,  the visibility graph (VG) method has been applied to the study different complex phenomena. One of the characteristics of this method is its ability to capture dynamic properties, such as non-trivial correlations in nonstationary time series, without introducing elaborate algorithms such as detrending. Seismic processes have been of great interest and their complete understanding is still an open problem. In this work we use the VG method to study the temporal correlations in the seismic sequences monitored in three regions of the subduction zone belonging to the Cocos plate. Our analysis allows estimate persistence and the temporal correlations in the seismic activity monitored in Michoacan State, Mexican Flat Slab and Tehuantepec Isthmus, showing differences in all three.
Understanding within-city interaction between surface and air temperatures
Authors: Naserikia Marzie , Hart Melissa A. , Nazarian Negin , Bechtel Benjamin , Nice Kerry A.
Published: February 2023

Urban heat is a local scale warming effect associated with urban areas where most of the world's population live. Due to the scarcity of air temperature (Ta) data, urban heat studies have been mostly focused on Land Surface Temperature (LST) extracted from satellite imagery and a quantitative understanding of how LST interacts with Ta within a city is still lacking. Using crowdsourced weather station data in Sydney, Australia, combined with high resolution satellite images and urban datasets (such as Local Climate Zone (LCZ) and building-level urban data), we explore the interaction between Ta and LST, and their intra-urban variabilities during different seasons. We found that LST and Ta have different characteristics and their dependency varies by season and LCZ. When exploring the relationship between Ta, LST, and variables describing the urban structure, such as building fraction, the correlation between LST and urban structure was stronger and more seasonal dependent than the Ta-urban form relationship. Moreover, stronger correlations between LST and Ta were observed in the less built-up areas within the city. We also found that the determinants of LST variability are different from the contributing factors of Ta. These findings provide new insights for quantitatively investigating surface and canopy urban heat and their relationship with land cover, providing fit-for-purpose information to mitigate the adverse effects of urban overheating at local and global scales. 
An assessment of sea-air CO2 flux in the Arctic Ocean from 1985 to 2018
Authors: Yasunaka Sayaka , Manizza Manfredi , Terhaar Jens , Olsen Are , Yamaguchi Ryohei , Landschützer Peter , Watanabe Eiji , Carroll Dustin , Adiwira Hanani , Müller Jens , Hauck Judith
Published: February 2023

As a contribution to the Regional Carbon Cycle Assessment and Processes phase 2 (RECCAP2) project, we present synthesized estimates of the Arctic Ocean CO2 uptake and their uncertainties from state-of-the-art surface ocean pCO2-observation products, global and regional ocean biogeochemical models and atmospheric inversions. For the period of 1985−2018, the Arctic Ocean represents a net sink of CO2 of 103 ± 19 TgC yr−1 in the pCO2 products and 92 ± 30 TgC yr−1 in the ocean biogeochemical models. While the long-term mean CO2 uptake in the Arctic Ocean is primarily caused by steady-state fluxes of natural carbon, it is enhanced 28% by the atmospheric CO2 increase and 15% by climate change. Moreover, the climate effect in the Arctic Ocean has become more important in recent years. The CO2 uptake peaks in late summer and early autumn, and is low in winter because the sea ice cover inhibits sea-air fluxes. The annual mean of CO2 uptake increased due to the decreasing sea ice concentration both in the pCO2 products and the ocean biogeochemical models. Both, the mean CO2 uptake and the trend, is substantially weaker in the atmospheric inversions. Uncertainty across all estimates is large especially in the estimated surface ocean pCO2 values in the East Siberian Sea and the Laptev Sea, due to scarcity of observations and missing processes in models, such as land-sea fluxes and sediment dynamics.
Investigating Freeze/Thaw soil emissions of nitric oxide using in situ and Tropomi observations
Authors: Hickman Jonathan , Dammers Enrico , Pusede Sally , Miles Madeline , Suyker Andy , Awada Tala , Maul Jude , Groffman Peter
Published: February 2023

Agricultural emissions of nitric oxide (NO) from soils can cause formation of tropospheric ozone and particulate matter pollution, and in the presence of ozone NO is rapidly transformed nitrogen dioxide (NO2), itself an air pollutant. Emissions of NO from soils can be highly episodic, with a large proportion of annual emissions occurring in pulses following fertilization or wetting of dry soils. Freeze-thaw events may also be an important source of NO pulses, but the magnitude of these emissions is poorly understood, as are the mechanisms underlying freeze-thaw NO pulses and their influence on atmospheric composition and air quality.  Here we use daily observations of NO2 and air temperature for 2018-2021 from atmospheric monitoring stations in the Corn Belt of the midwestern United States to evaluate the potential influence of freeze/thaw events on atmospheric NOx.  We supplement these data with retrievals of NO2 from the Tropospheric Pollution Monitoring Instrument (TROPOMI) screened to include acceptable retrievals over snow, retrievals of soil freeze/thaw status from the Soil Moisture Active Passive project (SMAP), and observed and reanalyzed soil temperature.  We find evidence for elevated NO2 concentrations during winter months, including instances of elevated concentrations at the onset of spring thaw.  Freezing degree days—the accumulation of average daily temperature for days with soil temperature maxima of 0°C or less—fail to act as a clear predictor of the magnitude of post-thaw concentrations.  These results will be integrated with complementary high temporal-resolution eddy covariance flux measurements at a long-term agricultural research station in Nebraska, along with soil core incubations involving biogeochemical and molecular analyses, to provide insights into the magnitude of freeze/thaw fluxes and their underlying mechanisms.
The radiation interception and transmission in strip intercropping system
Authors: Dong Liming , Zeng Wenzhi , Lu Yuchao , Huang Jiesheng
Published: February 2023

Intercropping, growing at least two different crop species simultaneously in the same field, is a significant cropping system for global food security with more practice and attention recent years. The most remarkable advantage of intercropping is producing a higher yield or income due to more efficient use of agricultural sources. Specifically, the intercropping system utilizes nutrient and water more efficiently underground and intercepts more radiation aboveground. However, modeling intercropping system by crop model is still difficult and has two dominant challenges. One challenge is to quantify the competition of underground source between intercropped species, and the other one is to determine the radiation partitioning by intercropped species. With the view factor theory applied in radiation transmission, several models were established to simulate the light competition of strip intercropping, but most of the models ignore solar incident angles variation during one day and assume the indirect light traverse a whole hedgerow of the taller canopy. Although many models make great attempt on partitioning the indirect light, the extinction coefficient is not matched with the beer’s law. In our study, the radiation transmission model is based on geometrical relationships of crop height, calculating a beam transmission by spatial and temporal integration. Specifically, the same with direct light, the extinction coefficient of an indirect beam is established a numerical functional relation with the solar incident angle which is defined by crop heights and row widths of intercropped species. Furthermore, Gauss-Legendre integral formula are used to solve the indefinite integral caused by angular relationship during the temporal integration. The optimal number of nodes in Gauss-Legendre integral formula is five in our study and the error is generally less than 1%. Compared with existed models, the radiation interception model in our study is more stable and precise especially when the heights of crops are close or greatly discrepant. Further study including border row effect theory and heterogeneous canopy theory is also able to applied in our model.
UAS applications in high-resolution topographic change, land use classification, and sub-surface geophysical mapping
Authors: Rodgers Mel , Malservisi Rocco , Van Alphen Robert , Sadeghi Chorsi Taha , Dixon Timothy , Connor Charles
Published: February 2023

The use of unoccupied aerial systems (UAS) in geoscience has dramatically improved our ability to collect data at high resolution, minimal cost, and in rapid response to sudden events. The wide range of sensor and platform configurations gives scientists great flexibility in survey design and data collection. Satellite remote sensing data has exceptional spatial coverage and continues to increase its data acquisition to meter-level resolution. UAS data can image to the cm-level resolution but lacks the same spatial coverage as satellite. By combining and comparing UAS data with satellite and ground-based remote sensing data we can utilize the different strengths of these systems. Here we demonstrate various UAS applications in high-resolution topographic change, land use classification, and sub-surface geological mapping. We use UAS payloads such as RTK georeferenced RGB and multispectral images, lidar, and magnetic sensors to image surface changes and sub-surface structures. We demonstrate the need for post-processing (PPK) high precision GNSS rover locations over utilizing only RTK position information.Florida, USA, is home to rapidly changing beaches and wetlands, which are highly susceptible to our changing climate and destructive storm events. We show examples from beaches and wetlands in Pinellas County, Florida, USA where we have a) imaged the emergence and development of a barrier island, b) developed automated land use classification using photogrammetry and multispectral data, c) evaluated the impacts of a major hurricane event on a recently renourished beach. Pacaya Volcano, Guatemala, is an active volcano with frequent lava flows and historical flank collapse events. Using a combination of satellite DEMs, ground-based Terrestrial Radar Interferometry data, and UAS RGB SfM-photogrammetry, we have imaged recent lava flows in high-resolution showing details of lava flow levees and other structures. By comparing our data to pre-eruption satellite DEMs we can evaluate the volume and morphology of recently emplaced lava flows. In addition, we have collected magnetic data over recent lava flows that allows us to image the sub-surface structure of the lava flows and model lava flow properties. UASs are a powerful tool for remote sensing, geodetic, and geophysical data collection. They augment satellite and ground-based methodologies and by combining multidisciplinary data from these platforms we can image the earth in greater spatial and temporal detail than ever before.  
A Deep Learning Method for Detecting Floating Garbage in Urban Rivers
Authors: Nunkhaw Maiyatat , Miyamoto Hitoshi
Published: February 2023

In recent years, plastic pollution in the ocean has become a global environmental problem, deeply affecting the ecosystem as well. In fact, 80 percent of ocean plastic was reported to come from terrestrial river basins, therefore it would be extremely important to recognize how much plastic waste runoff from rivers around the world was. In response to this global environmental problem, an image analysis method for monitoring river waste transport has recently been started to propose. However, this image analysis indicated a difficulty to fully detect plastic waste in various types of waters because it needed to use a color difference in each water to classify the type of waste.This paper tried to develop an automated detection system based on a modified convolutional neural network (CNN) for detecting and counting floating river waste. The CNN used in this research was You Only Look Once (YOLO) architecture with a fine-tuning for adjusting it to the waste detection. The proposed model has further been improved its accuracy through the enlarged image processing. As for the waste counting, an object tracking method, e.g., deep SORT, could be used with the proposed model in video frames of flowing water.  The results showed that the proposed YOLO model with enlarged image processing achieved the evaluation values of mean average precision mAP (%) of can, carton, plastic bottle, foam, glass, paper, and plastic were 95, 89, 94, 97, 92, 71, and 81, respectively. Moreover, the proposed mode with deep SORT has achieved the F1-score (%) of 80, 80, 75, 85, 100, 100, and 50, in each waste type. Consequently, the proposed model could be feasible for identifying and counting flowing river waste accurately. The future research work should improve the counting accuracy and further develop an automated model implementation method.
Applying a Bayesian Framework to Track Binational (Canada-USA) Loads and Sources
Authors: Ouellet Felix , Richards Agnes , Neumann Alexey , Benoy Glenn , Arhonditsis George
Published: February 2023

The Red-Assiniboine River Basin (RARB) spans the Canada-USA border and discharges into Lake Winnipeg via the Red River. Recurrent harmful algal blooms caused by nutrient runoff coined Lake Winnipeg as “Canada’s sickest lake” and “most threatened in the World”. Invasive species such zebra mussels and spiny-water fleas have disrupted the aquatic ecosystem.SPAtially Referenced Regression On Watershed Attributes (SPARROW) is a watershed model that follows a stream network and relates water quality conditions to nutrient sources, landscape delivery factors, nutrient transport, and losses in streams and reservoirs/lakes. We ported components of the first binational SPARROW model (deterministic calibrations) for RARB to a Bayesian framework to account for the main sources of uncertainty: errors resulting from loading estimates, parametric uncertainty (incorporated with prior distributions based on literature values), and model structural error. Open-source languages were used: Python, R, and WinBUGS. The limits of the computational capacity of WinBUGS were tested, with a total of over 70,000 catchments across the RARB.We identified hot spots in Canada and USA at a sub-watershed scale, where wastewater treatment plants and agricultural inputs were the main contributors of Total Phosphorus (TP) to Lake Winnipeg. Within those hot spots, we looked at hot spots at the catchment scale, where wastewater treatment plants were contributing to nearly 100% of the TP loading.We will present various scenarios testing hypotheses on different TP sources, such as the inclusion of urban areas, the subdivision of selected source variables, and the variation of wastewater treatment plant loadings.
Geoheritage of Torres, Southern Brazil: Disseminating its geodiversity and promoting geotourism
Authors: Sander Victória , Batista dos Santos Filho Marcos Antonio , Lopes Diniz Jaqueline , Silva e Souza Leite Luiz Filipe , Candido Mariane , Rodrigues Bruno Mauro Daniel , Ebling Priscila dos Santos , Luft-Souza Fernanda , Vázquez-García Bernardo , Rodrigues Daiane , Nunes Aumond Gustavo , Elisabeth da Roch Maria
Published: February 2023

Situated on the northern coast of the Rio Grande do Sul state, in the southern region of Brazil, the Torres municipality contains beautiful landscapes, with a variety of natural sights such as great dunes, lagoons, and its famous volcanic rock natural towers. The main geological processes that sculpted this region are associated with wind activity and the numerous rises and falls of the sea level that occurred between the Pleistocene to the present day. Torres is a highly popular tourist beach, and sees its population grow by nearly 500% during the summer months. Due to it being a tourism hotspot and its incredible geodiversity, Torres is one of the main areas of the “Caminhos dos Cânions do Sul” Geopark (CCSG), a 2,830 km2 area that encompasses seven municipalities situated at the boundary of the Rio Grande do Sul and Santa Catarina states. The geopark has three pillars, education, geoconservation, and tourism, and it aims to boost the economic, sociocultural, and environmental growth of the region in a sustainable manner. The geopark also seeks to help in the preservation of geological sites that most represent its regional diversity, such as the great Juro-Cretaceous volcano-sedimentary rock towers that give the city of Torres its name (which translates from the Portuguese to “Towers”). These structures, which can be seen throughout Torres’ coastline, are composed mostly of the basalts of the Serra Geral Group, which overlay the sandstones of the Botucatu paleodesert. In this municipality, the CCSG has, through lectures, itinerant exhibitions, training courses, and participation in cultural and scientific events, helped increase public consciousness regarding the importance of preserving and valorizing the area's geoheritage. In this work, we present a project developed through a partnership involving the Torres prefecture, the CCSG, and the GeoRoteiros group, which has as its objective the installation of information plaques about the geological evolution of the “Morros Testemunhos” and the state's Coastal Plain. We plan to install 10 plaques throughout the beach, each displaying didactic images and texts in an accessible language for the general public. The information available on these plaques will be summarized; in case the reader wishes to learn more, a QR Code will be available to take them to the websites of the organizing institutions, where they can not only read additional information, but also watch videos discussing the geosites of the geopark. This is a pilot project which will ascertain the viability of developing similar projects for the other municipalities that compose the CCSG.
Predictions of North Atlantic tropical cyclone activity out to 4 weeks with global MPAS simulations
Authors: Nystrom Robert , Judt Falko
Published: February 2023

The very active month of September 2020 included the formation of 10 named storms, the most on record for the month of September, and 5 concurrent tropical cyclones (TCs) in the North Atlantic basin on September 14th. The Model for Prediction Across Scales (MPAS) is used to explore potential opportunity to predict TC activity out to 4 weeks. First, the MPAS model climatology for September TC activity is established. Next, the predictability of an active September is explored using MPAS simulations with initial atmospheric and oceanic conditions from the global forecast system (GFS) and compared with MPAS climatology. MPAS simulations for 2020 are initialized over the last two weeks of August and run freely through September. The total number of TCs, TC days, accumulated cyclone energy (ACE), and the track density are each evaluated relative to observations. In addition, the simulations resulting in the most and least active month are analyzed in further detail to understand why those model simulations predicted an active or inactive September. Lastly, differences with and without a regionally refined 3 km mesh are explored.
Addressing discoverability, trust and data quality in peer-to-peer distributed databases for citizen science
Authors: Malard-Adam Julien , Krishnankutty Sheeja , Nallusamy Anandaraja , Medema Wietske
Published: February 2023

Peer-to-peer distributed databases show promise for lowering the barrier to entry for citizen science projects. These databases, which do not require a centralised server to store and exchange data, instead use participants’ devices (phones or computers) to store and transfer data directly between project participants. This offers concrete advantages in terms of avoiding usually very costly and time-consuming server maintenance for the research team, as well as improving data access and sovereignty for the participating communities.However, several technical challenges remain to the routine use of distributed databases in citizen science projects. In particular, indexing data and discovering peers who hold data of interest or from the same project; managing safety, trust and permissions; and ensuring data quality all without relying on a central server to perform these functions requires a rethinking of the standard paradigms of database and user account management.This presentation will give a brief overview of the Constellation software for distributed scientific databases before presenting several novel approaches (concentric recursive data search, user network-centric trust, and multiple data quality verification layers) it has adopted to respond to the above-mentioned challenges. Examples of concrete applications of Constellation for data sharing in the fields of hydrology and agronomy will be included.
New GNSS Observations of Crustal Deformation due to Ice Mass Loss in the Amundsen Sea Region, Antarctica
Authors: Wilson Terry , Gómez Demián , Matheny Peter , Bevis Michael , Durkin William J. , Kendrick Eric , Konfal Stephanie , Saddler David
Published: February 2023

Twelve continuous GNSS systems are deployed on bedrock across the Amundsen Embayment region, spanning the Pine Island, Thwaites and Pope-Smith-Kohler (PSK) glacial drainage network of the West Antarctic Ice Sheet.  Continuous daily position time series for these sites range from 4 to 12 years, yielding reliable crustal motion velocity solutions at these fast-moving bedrock sites. Remarkably, multiple stations record sustained uplift of 40-50 mm/yr.  Maximum uplift defined by the current distribution of sites is centered on the Pope-Smith-Kohler glaciers, where rapid thinning and grounding line retreat is well documented. Horizontal bedrock displacements, which are particularly sensitive to the location of changing surface mass loads, show a clear radial pattern with motion outward away from upstream portions of the Pope/Smith glaciers. Several modeling studies suggest there is a viscous deformation response to this decadal mass loss. Our modeling, however, shows that elastic deformation response explains nearly the entire measured signal at the PSK region sites. We will present new modeling results and discuss implications for ongoing cryosphere-solid Earth interactions.
Synchronized mapping of water quantity and quality of a reservoir through an unmanned surface vehicle: A case study of the Daljeon reservoir, South Korea
Authors: Lee Kwang-Hun , Ali Shahid , Kim Yena , Lee Ki-Taek , Kwon Sae Yun , Kam Jonghun
Published: February 2023

This study developed a synchronized mapping technique for water quantity and quality via an unmanned surface vehicle (USV). The USV with the acoustic doppler current profiler (ADCP) and the multiparameter sonde of water quality sensors (YSI EXO2) was used for identifying spatial and seasonal patterns of the Daljeon reservoir in South Korea. With this technique, we measured bathymetry and nitrate concentration from August 2021 through July 2022 at the high resolution spatial resolution and tested the sensitivity of estimated nitrate loads to spatial variations of input variables (water volumes and nitrate concentrations). Results showed that measured bathymetry and nitrate concentration varies over the water surface of the reservoir and time, which are associated with seasonal variations of temperature and precipitation. Despite weak spatial variations of the nitrate concentration, the water level of the reservoirs showed strong spatiotemporal variations depending on the topography of the reservoir and the  rainfall occurrence. Furthermore, we figured out using the mean for nitrate load was underestimated by -20% of the nitrate load estimates by considering spatial variation. High-resolution bathymetry measurement play a role in estimating nitrate loads with a minor impact of spatial variations of measured nitrate concentrations. We found that rainfall occurrences more likely increase estimated nitrate loads when it accounts for spatially variations of input variables, particularly water volumes. This study proved the potential utility of USV in simultaneously monitoring water quantity and quality for integrative water resource management for sustainably development of our communities.
Impacts of forest harvesting on mercury concentration, methylation and demethylation in soils and sediment in Canadian boreal forests 
Authors: Huang Haiyong , Mitchell Carl
Published: February 2023

Methylmercury (MeHg) bioaccumulates through terrestrial and aquatic food webs and can irreversibly damage the central nervous system, particularly in frequent fish consumers. Forest harvesting can result in increased MeHg exports from watersheds. To date, little empirical research has been conducted to examine mercury (Hg) methylation and MeHg demethylation processes happening within soils and sediment of forest-harvested watersheds; and mechanistic details remain relatively scarce. A field investigation was therefore carried out in 5 forest-harvested and 2 unharvested boreal watersheds in northwestern Ontario Canada to better understand MeHg production and degradation in this ecosystem. Total Hg (THg) and MeHg concentrations as well as first-order potential rate constants for Hg methylation and MeHg demethylation potentials (Kmeth and Kdemeth) in soils and stream sediment were determined. Specifically, these values were compared between years before (2019) and after (2020) forest harvesting activities, as well as between harvested and unharvested watersheds in the same years. We found some increases in THg and MeHg concentrations in upland soils in harvested forests, but the overall concentrations were still relatively low. Concentrations of THg and MeHg in wetland/riparian soils remained relatively consistent and some even declined in the first year after harvesting. We found considerable increases in THg and MeHg concentrations, as well as Kmeth in stream sediment in two of the harvested watersheds, both which had significantly narrower than normal vegetated buffer zones. These results suggest that short-term (< 1 year) mercury-related impacts of harvesting activities are mostly constrained within the harvested upland zones but may stretch into downgradient stream sediment when machinery damage is very close to streams. 