bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation on the refractive index of ambient aerosols as fine- and coarse-mode volume size distribution
Authors: Shin Juseon , Sim Juhyeon , Kim Dukhyeon , Noh Youngmin
Published: February 2023

The refractive index (RI) of aerosol is an important parameter that reflects the scattering and absorption capacity of aerosol and is widely used in atmospheric models and remote sensing studies. It depends on several properties such as chemical species, moisture content, etc. RI is usually obtained by the chemical method using a volume mixing ratio of known chemicals and by the optical method based on extinction, scattering and/or absorption coefficient using Mie theory. However, these methods are complicated and are mainly for singular particles. In this study, we tried to make a simple method to estimate RI by measuring the extinction coefficient from camera images and size distribution from the optical particle counter (OPC). We used the wavelength of Red-Green-Blue color as 597, 534, and 459 nm to calculate the extinction coefficient and the number size distribution to retrieve the volume size distribution obtained by OPC. The volume size distribution is expressed by six parameters of two gaussian graphs for fine and coarse-mode particles. We got the volume, median radius, and standard deviation of fine and coarse aerosol peaks. The measurement site was the port area in Busan, Korea. We sometimes discovered the emission of particles but mainly measured for clear days. We effectively retrieved six parameters determining the volume size distribution of ambient aerosols and tried to inverse RI as total, fine, and coarse particles using the nonlinear optimization method. We mainly considered the scattering effects of ambient aerosols, so we focused on the real part of RI. The retrieved RI was from 1.27 to 1.50 and showed different values on fine- and coarse-mode size particles. The results were lower than other RI measurement studies, so we need to validate more. However, we identified the possibility of retrieving the RI of aerosols using the known size distribution retrieved from OPC and the three-color extinctions from the camera.
What are the controls for delta front slope failure? Insights from detailed monitoring at Squamish Delta, British Columbia.
Authors: Zulkifli Zaki , Clare Michael , Minshull Timothy
Published: February 2023

Submarine slope failures pose a hazard to seafloor infrastructure and coastal communities. Given the high population densities, slope failures can have a particularly significant impact around river deltas, generating damaging tsunamis and breaking critical telecommunications connections. Despite the risks they pose, a lack of detailed monitoring means that the factors that lead to slope collapse remain poorly constrained. Numerical modelling is typically used to assess future slope stability. Still, sparse existing data ensure that we cannot yet determine how submerged delta slopes evolve and progress to failure at the field scale. Here, we aim to close this gap by analysing repeat seafloor surveys of the submerged Squamish prodelta, British Columbia, to determine the physical controls on slope instability. Multibeam bathymetric surveys were performed on 93 consecutive weekdays in 2011, during which time at least five large (>50,000 m3) delta slope collapses occurred, as well as numerous smaller slope failures. These surveys allow us to determine how the delta slope and geometry changes on an unusually detailed timeframe (i.e. daily) in the build-up to slope collapse and how it relates to variable sediment supply from the feeding river and tidal fluctuations. Analysis of the five large collapses reveals that a single mechanism is not responsible for every failure. So, we investigated how different parts of the delta encounter major failure at different times and locations by measuring and mapping out the delta head and associating it with sediment input and tide high. From this, we found that slope failure is likely due to a combination of enhanced slope geometry due to delta lip progradation and pore pressure fluctuations relating to sediment loading and tidal effects.
Spatial distribution and historical trend of microplastic pollution in sediments from enclosed bays of South Korea
Authors: Eo Soeun , Hong Sang Hee , Song Young Kyoung , Cho Youna , Han Gi Myung , Shim Won Joon
Published: February 2023

Seaﬂoor sediment is an important sink for microplastics, and vertical profile of microplastic accumulation in a sediment core can provide historical pollution trend. However, microplastic pollution in coastal sediment has not been addressed well, and a few studies have investigated the trends of microplastic pollution in age-dated core sediments. In this study, the microplastics in surface sediments in urban, aquafarm and reference areas of South Korea were analyzed to evaluate the pollution characteristics of microplastic according to different sea area use patterns. In addition, the historical trend of microplastic pollution was investigated in core sediments in the urban and aquafarm areas. The abundance of microplastics in surface sediment were in order of urban area (6,887 ± 6,100 particles/kg d.w.), aquafarm area (5,121 ± 2,428 particles/kg d.w.), and reference area (2,474 ± 522 particles/kg d.w.). Polymer types were diverse in the urban area, and expanded polystyrene used for buoys was dominant in the aquafarm area. Fragment type microplastic was dominant in all three areas, and the proportion of fiber was higher in urban and aquafarm areas than in reference area. The polymer composition of fiber was different in urban (polyester 51% and polypropylene (PP) 29%) and aquafarm areas (PP 84% and polyamide 13%). These results support that the characteristics of microplastic pollution well reflect the sea area use patterns. Historical trend of microplastic pollution has increased since the 1980s and the increasing rate steeply increased around the early and mid-2000s in both the core samples. Their increasing trend reflected the influence of population or surrounding input sources (i.e. effluent discharge amount of a wastewater treatment plant). The clear increasing trend of historical microplastic pollution up to now indicates that more efforts is highly required to reduce the microplastic pollution. 
Accurate quantification of sediment conveyance following the 2016 Kaikōura earthquake, New Zealand
Authors: Jones Katie , Howarth Jamie , Massey Chris , Sirguey Pascal , Lague Dimitri , Bernard Thomas
Published: February 2023

Evaluating the influence of earthquakes on erosion, landscape evolution and sediment-related hazards requires quantifying the volume and velocity of post-seismic sediment cascades. However, accurate estimates of post-earthquake sediment transfers remain rare. Following the 2016 MW7.8 Kaikōura earthquake in New Zealand, the volume of post-seismic erosion was quantified directly by measuring the ground surface change between 4 lidar surveys captured in 2016, 2017, 2019 and 2021 using the multiscale model-to-model cloud comparison (M3C2) algorithm. The lidar surveys covered the 62 km2 Hapuku and 66 km2 Kowhai river catchments within the Seaward Kaikōura Range, representing the two catchments with the highest density of co-seismic landsliding.The total co-seismic landslide source volume for the Hapuku Catchment was 30 ± 6 M m3,the catchment being dominated by a 17 M m3 rock avalanche which dammed the Hapuku River. In the 5 years after the earthquake a total of 10.60 ± 0.22 M m3 of sediment was post-seismically eroded (equivalent to ~26% of the co-seismic landslide debris volume when considering bulking of the landslide deposit). A total of 9.71 ± 0.23 M m3 of sediment was delivered to the riverbed resulting in considerable riverbed aggradation and 3.58 ± 0.28 M m3 was inferred to have been transported beyond the rangefront of the Seaward Kaikōura Range (equivalent to ~9% of the co-seismic landslide debris). The total co-seismic landslide source volume for the Kowhai Catchment was only 13 +4/-3 M m3. Over the 5 years 2.02 ± 0.10 M m3 of sediment was post-seismically eroded, equal to ~13% of the co-seismic landslide debris volume within the catchment. The volume delivered to the riverbed, 1.29 ± 0.10 M m3 and 0.85 ± 0.13 M m3 is presumed to have been transported beyond the rangefront (equivalent to ~5% of the co-seismic landslide debris).From these volumes, the rates at which the co-seismic landslide sediment was eroded from hillslopes, delivered off-slope to channels and exported from the range front were calculated. When projected, these rates of sediment conveyance suggest the volume of co-seismically generated sediment is likely to be evacuated from the rangefront within or close to the recurrence interval for ground motions equivalent to the Kaikōura earthquake. The Hapuku and Kowhai river catchments being examples of where co-seismic landsliding counterbalanced uplift.
How do differences in interpreting seismic images affect estimates of geological slip rates?
Authors: Hu Wan-Lin
Published: February 2023

Uncertainties of geological structural geometry constructed based on seismic reflections can stem from data acquisition, processing, analysis, or interpretation. Uncertainties arising from structural interpretations and subsequent estimates of geological slip have been particularly less quantified and discussed. To illustrate the implications of interpretation uncertainties for seismic potential and structural evolution, I use an example of a shear fault-bend fold in the central Himalaya. I apply a simple solution from the kinematic model of shear fault-bend folding to resolve the geological input slip of given structure and then compare the result with a previous study to show how differences in structural interpretations could impact dependent conclusions. The findings show that only a little variance in interpretations owing to subjectivity or an unclear seismic image could yield geological slip rates differing by up to about 10 mm/yr, resulting in significantly different scenarios of seismic potential. To reduce unavoidable subjectivity, this study also suggests that the epistemic uncertainty in raw data should be included in interpretations and conclusions.
Late Cenozoic Crustal Reactivation of the North Tibetan Foreland, Western Hexi Corridor, Beishan, and Gobi Corridor: Implications for Intraplate Fault Networks, Mountain Building Processes and Earthquake Hazards in Slowly Deforming Regions of Central Asia
Authors: Cunningham Dickson , Yang Haibo , Zhang Jin
Published: February 2023

The active deformation field between northern Tibet and central Mongolia is dominated by diffuse sinistral transpressional reactivation of the southern Altaids Phanerozoic terrane collage.   The angular relationship between NE-directed SHmax and pre-existing basement trends is the dominant control on Quaternary fault kinematics.  Along Tibet’s northern margin, the Altyn Tagh system is widening northwards by transpressional duplexing.  The Nanjieshan and Sanweishan comprise sinistral oblique-slip thrust ridges within a regional asymmetric flower structure centered on the Altyn Tagh Fault.  In the southern Beishan, interconnected lensoidal domains of transpressional and transtensional faulting are subtly indicated by Quaternary fault scarps, low-relief rejuvenated landscapes and alluvial sedimentation.  The SE Beishan and western Hexi Corridor region contain numerous Late Quaternary fault systems including the Heishan-Jinta'Nanshan sinistral strike-slip corridor and the Helishan-Longshoushan fault array that connects eastwards with the transtensional grabens of the Yabrai and Langshan in the eastern Alxa Block.  Further north, the Paleozoic terrane collage of the Gobi Corridor was repeatedly reactivated during the Permo-Triassic, Jurassic, Cretaceous and Neogene.  Late Cenozoic reactivation was likely facilitated by thermal weakening of the crust due to Jurassic-Miocene volcanism, and diffuse Cretaceous rifting and crustal thinning.  Although terrane boundaries and other faults are reactivated in many areas, thrust and oblique-slip reactivation of WNW striking shallowly dipping sedimentary bedding and metamorphic fabrics is equally important.  Conversely, modern E-W trending strike-slip faults in the Gobi Altai typically crosscut older basement trends. In the Altai and Gobi Altai, the Late Cenozoic fault array has created a transpressional  basin and range physiographic province.  Coalescence of separate ranges into topographically continuous mountain belts in the Altai, Gobi Altai and easternmost Tien Shan is an important mechanism of transpressional mountain building not predicted by classical plate tectonic models.  Throughout the vast deforming region north of Tibet, tectonic loading is shared amongst a diffuse fault network challenging assumptions about earthquake recurrence intervals and seismic hazard forecasting.
A multiple-benefit framework for implementing nature-based solutions using conservation finance
Authors: Maurer Tessa , Seipp Kimberly , Elias Micah , Saksa Phil
Published: February 2023

Sitting at the intersection of knowledge production and project implementation, our work as conservation finance project developers leverages economic and other benefits of environmental restoration to attract new and diverse funding sources for nature-based solutions (NBS). Our work supports project activities ranging from variable density thinning and prescribed burning to low-tech and process-based riparian restoration. In our experience, NBS presents a powerful, cost-effective opportunity to create scaled improvements in ecosystem function. However, funding NBS projects can be challenging, as some NBS outcomes are only achieved through large-scale landscape restoration, which is expensive, or are realized gradually over a period of time following restoration activities. Conservation finance is one tool that can catalyze meaningful NBS work at scale by providing the necessary upfront capital for projects while contracting funding commitments based on outcomes over time. Using several examples of successful NBS projects, we present a process-based, multiple-benefit framework to demonstrate how NBS can be leveraged to increase funds and enable financing. This framework is grounded in western U.S. forest management to address catastrophic wildfire, but can be applied in other regions and for other types of restoration activities. This approach addresses the logistical, governance, and sociocultural challenges we have encountered to leveraging NBS within a conservation finance framework. We also propose future avenues of research to help increase investment based on NBS. These include formalizing metrics for measuring and monitoring of different NBS activities, managing the uncertainty and expectations around outcomes of NBS projects, and incorporating the future impacts of climate change into NBS models and planning. By describing this work in a U.S. context, we hope to catalyze a discussion about how the needs and opportunities identified in our projects can inform work in Europe and vice versa.
The importance of underestimated local vertical land motion component in sea-level projections: A case study from the Oka estuary, northern Spain
Authors: Li Tanghua , García-Artola Ane , Walker Jennifer , Cearreta Alejandro , Horton Benjamin
Published: February 2023

Vertical land motion (VLM) is an important component in relative sea-level (RSL) projections, especially at regional to local scales and over the short to medium term. However, VLM is difficult to derive because of a lack of long-term instrumental records (e.g., GPS, tide gauge). Geological data offer an alternative, revealing RSL histories over thousands of years that can be compared with glacial isostatic adjustment (GIA) models to isolate VLM.Here, we present a case study from the Oka estuary, northern Spain. We apply two GIA models for the Atlantic coast of Europe with different ice model inputs (ICE-6G_C and ANU-ICE) but the same 3D Earth model. Both models fit well with the late Holocene RSL data along the Atlantic coast of Europe, with misfit statistics < 1.5, except the Oka estuary region, where both models show notable misfits with misfit statistics > 4.5. The significant misfits of both models in the Oka estuary region are indicative of local subsidence. The nearby GPS (station SOPU) with 15 years records shows a VLM rate of -0.96 ± 0.57 mm/yr (subsiding) compared to -0.15 ± 0.40 mm/yr to -2.48 ± 0.37 mm/yr elsewhere along the Atlantic coast of Europe. The VLM rate of SOPU accounts for the misfit between the GIA models and late Holocene RSL data, which decreases by ~90% from > 4.5 to ~0.5 after the subsidence correction of the late Holocene RSL data. The VLM rate incorporated in IPCC AR6 projections in Oka estuary is ~0.18 mm/yr (uplifting), which is contradictory in direction. Therefore, the projected sea-level rise rate is underestimated by 19 - 25% by 2030, 14 - 20% by 2050 and 9 - 26% by 2100 under the five Shared Socioeconomic Pathway (SSP) scenarios (SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). Our study indicates the importance of considering local/regional VLM component in sea-level projections.
The Effect of Horizontal Advection on the Nocturnal Surface Urban Heat Island Using MODIS Satellite over Birmingham and the West Midlands, United Kingdom
Authors: Feng Jiali , Wang Yuexia , Cai Xiaoming , Chapman Lee
Published: February 2023

It has been well-recognised that the horizontal advection can modulate the downwind footprint of the urban heat island (UHI). However, limited studies have considered the urban heat advection (UHA) generated from this boundary-layer process, mainly due to the lack of a dense network of sensor to sufficiently resolve the local climate in a city. For the first time, this study explores the possible influence of the horizontal advection on the nocturnal surface urban heat island sensed by the MODIS satellite (sUHA) over a ten-year period. Results show that the heat transport from urban to downwind areas can be observed by the satellite instrument. A significant warming up to 0.5 ºC and 1.7 ºC were found at city (Birmingham) and regional scale (West Midlands area), respectively. The amplification of the sUHA at regional scale was largely attributed to the topography effects according to the significant correlation between sUHA and a topography index (i.e. R2=0.53). An approximate 0.5 ºC can be corrected for sUHA after minimising the topography impact by applying a statistical method. Overall, this study highlighted the value of the satellite instrument to investigate the UHA at both city and regional scale. However, more importantly, the topography was found to have considerable influences on regulating the heat transfer from urban to its downwind areas, which provides further implications for urban planning and risk management with respect to the UHI.
UAV and SnowModel Estimates of Wind Driven Snow in Eastern USA Avalanche Terrain
Authors: Wagner Cameron , Hunsaker Adam , Jacobs Jennifer
Published: February 2023

Mount Washington, New Hampshire’s east aspect glacial cirques are subject to frequent wind slab avalanche problems due to high winds and ample snowfall in fetch areas above the cirques.  Quantification of these slabs’ location, extent and depth is in integral part of avalanche forecasting and risk assessment. This research used SnowModel, a spatially distributed snow-evolution modeling system, to model wind slab depth maps using Mount Washington Observatory weather station data on a 1-meter grid scale. SnowModel’s SnowTran-3D, a snow redistribution by wind algorithm, is tested for one of the first times in the Eastern United States. Snowpack seasonal evolution and accumulation event-based model performance is calibrated and validated using 15 snow depth maps. These maps were constructed via structure from motion (SfM) analysis photogrammetry. SfM maps were derived from optical imagery collected using an Unmanned Aerial System (UAS) and were able to quantify wind slab depth with a 5cm spatial resolution.
Changes in soil chemical properties along afforestation chronosequence in the dried Aral Sea bed, Kazakhstan, from 1990-2019
Authors: Kim Gaeun , Ahn Jieun , Chang Hanna , An Jiae , Son Yowhan
Published: February 2023

Desiccation of the Aral Sea left a vast area of unstable, saline, and barren seafloor. In response, afforestation using indigenous trees, mainly Haloxylon species, has been performed to ameliorate the soil. This study examined 1) changes in topsoil chemical properties after vegetation establishment based on 30-year chronosequence of afforested sites and 2) dynamics in the topsoil properties in two cases of naturally vegetated versus afforested areas. In August 2019, soils were sampled from the northeastern Aral Sea bed, Kazakhstan, where the shoreline retreated during the 1970s. We selected a non-saline area without any vegetation, a visibly salinized area without any natural vegetation, and 12 paired sites with predominantly sandy soil texture that were naturally vegetated or afforested during 1990, 2000, 2005, 2008, 2013, and 2017. In the 0‒10 cm soil layer, 3 points were sampled in each site and we analyzed soil pH, electrical conductivity (EC), total dissolved solids (TDS), exchangeable sodium percentage (ESP), total nitrogen (TN) and carbon (TC), total organic carbon (TOC), available phosphorus concentration (P2O5), exchangeable cation concentrations (K+, Mg2+, Ca2+, and Na+), and cation exchange capacity (CEC). The soil samples in chronosequence sites showed a wide range of EC, without any significant temporal trend. The pH ranged between 8.5 and 10.0, characterized soil as alkaline. CEC ranged from 9 to 45 cmolc kg-1. Soil pH, EC, and TDS variations among the chronosequence sites (natural or afforested) were not statistically significant. In contrast, we observed marginal increases in K+ and P2O5 after the vegetation establishment. Also, TN and TOC concentrations increased over time, significantly faster in afforested than in naturally vegetated sites. However, TC contents showed a sudden decrease in the oldest natural vegetation. This result may be partly attributed to the spatial variability in sampling locations used for the chronosequence analysis. Lastly, there were strong positive correlations among TOC, TN, K+, and P2O5; which imply an increase in soil organic materials’ contribution to nutrient accumulation and overall soil quality. In conclusion, afforestation contributed to soil amelioration but this effect was also observed in naturally vegetated sites.
Can process-based BGC models simulate drought-induced tree mortality worldwide?
Authors: Jo Nanghyeon , Agossou Casimir , Kim Eunsook , Lim Jong-Hwan , Kang Sinkyu
Published: February 2023

Drought-induced tree mortality has been increasing worldwide under climate change; therefore, forests will become more vulnerable as warming continues. With growing interest in tree decline due to increased climate variability, ecophysiological roles and dynamics of non-structural carbohydrates (NSCs) have drawn wide attention recently. Accordingly, a lot of field data have been collected, but these achievements were not well incorporated in process-based vegetation models yet, where NSCs ecophysiology was implicitly applied or ignored. In this study, we addressed five key modeling issues in simulating spatial and temporal patterns of NSCs dynamics across different scales as follows: (1) interconversion between dual NSCs pools (i.e., rapid soluble sugar and slown starch pools), (2) incorporation of the sink-limited growth allocation strategy, (3) hydraulic limitation of NSCs transports between organs, (4) feedback mechanisms between tree NSCs and root symbionts, and (5) large-scale simulations of NSCs dynamics. In addtion, we applied key issues (1) and (2) of NSCs to the BIOME-BGC model and evlauated across biomes. As a result, modified BGC model (BGC-NSCs) successfully simulated vegetation traits across different biomes, such as seasonal and interannual variations of St (mean R2 of, 0.55, 0.62), and site-specific SS-to-St ratios, while the model did not simulate the SS temporal variation well. Nevertheless, in the factor analysis of several variables for the global tree mortality data, physiological variables such as NSCs and PLC (Percent loss of conductivity) produced in the BGC-NSCs model were important. Despite limitations of the current BGC modeling and simple assumptions of mortality mechanisms, this study demonstrated a potential to use key ecophysiological variables for simulating widespread drought-induced mortality across different biomes and climate regions. 
Extended 3He-rich time periods observed by Solar Orbiter
Authors: Kouloumvakos Athanasios , Mason Glenn M. , Ho George C. , Allen Robert C. , Rouillard Alexis P. , Rodríguez-Pacheco Javier R. , Wimmer-Schweingruber Robert F. , Gómez-Herrero Raúl
Published: February 2023

Solar energetic particle (SEP) observations from Suprathermal Ion Spectrograph (SIS) which is part of the Energetic Particle Detector (EPD) suite on board the Solar Orbiter (SolO) mission, provide an unprecedented opportunity to study the composition and evolution of SEPs close at the Sun and to understand where SEPs are accelerated at the Sun and when released from their sources to interplanetary space. In this study, we examine 3He-rich time periods that last for many days. These extended 3He-rich periods that observed by SIS are particularly interesting because this rare isotope of He is not abundant in the solar corona and events rich of 3He are usually associated with transient and small "impulsive" SEP events. First, we compile a catalogue of extended 3He-rich time periods that were observed during the first three years of SolO mission and we determined and registered their characteristics (duration, composition, etc.). We also examined the spacecraft’s magnetic connectivity during these time periods and the characteristics of the connected regions. We find that, during the extended 3He-rich time periods, SolO is stably magnetically connected to an active region(s) for most cases. The connectivity usually changes near the boundaries of the time periods so the connectivity to the source region is an important element for the observation of these 3He-rich time periods. The active region(s) where SolO is magnetically connected during the time periods are typically very productive of solar events (flares, jets, CMEs). 
Loading effect on wave pumping driven seawater-groundwater circulation in submarine aquifer
Authors: Yu Shengchao , Zhang Xiaolang , Jiao Jiu Jimmy , Li Hailong
Published: February 2023

Tide and wave are both significant driven forces of submarine groundwater discharge (SGD). The hydrodynamic process of tidal SGD is well studied while wave induced part is still challenging to quantify. In this paper, an analytical study was performed to investigate wave pumping-driven SGD in subsea sediments. The loading effect of seawater weight overlying the seabed has been considered in the groundwater flow equation. Two dimensional simulations governed by this analytical solution were applied to examine water head fluctuations within permeable sediments. The analytical solution was validated by simulated water head fluctuations, which revealed the influence of poro-elastic property of sediment on the hydrodynamic process within the permeable seabed. The analytical and simulated results may provide guidance for assessing the wave-induced SGD and shed light on modeling the biogeochemistry process in wave dominated porous seabed environment.
Does surface warming over Western Europe affect the occurrence frequency of contrail forming regions?
Authors: Li Yun , Rohs Susanne , Krämer Martina , Petzold Andreas
Published: February 2023

The decade, 2012 to 2021, was the warmest on record, with the global mean near-surface air temperature in the most recent seven years, 2015 to 2021, keeping hitting record high. Europe, with an increase of 1.94 to 2.01 °C in the mean annual temperature since pre-industry level, is warming much faster than the global average (1.11 to 1.14 °C) (https://www.eea.europa.eu/ims/global-and-european-temperatures). Surface warming disrupts upper-air temperature, which will affect the humidity fields in the upper troposphere. Both ambient temperature and relative humidity with respect to ice (RHice) are key factors determining the formation and persistence of contrail cirrus clouds, which exert a net warming radiative forcing among aviation emissions (Lee et al., 2009; Lee et al., 2021).Previous studies have provided insights into the long-term trend and seasonal variability of upper-air temperature and relative humidity using airborne, radiosonde and reanalysis datasets (Petzold et al., 2020; Chen et al., 2015; Philandras et al., 2017; Essa et al., 2022). The variation of RHice in relation to the changing upper tropospheric temperature because of surface warming has, however, rarely been investigated.In this work, we use the temperature and RHice measurements over Western Europe from the European research infrastructure IAGOS (In-Service Aircraft for a Global Observing System; www.iagos.org) to study how the upper-air temperature and RHice distributions in the warmest seven years have changed seasonally and regionally compared to the IAGOS-MOZAIC period, 1995 to 2010, when the surface warming was not so drastic. We will focus on whether the occurrence frequency of contrail forming regions, i.e., slightly ice subsaturated to supersaturated regions in the upper troposphere, would be affected by the increasing warming climate, which could promote our understanding of contrail mitigation.[Note: This work is carried out under the frame of EU H2020 Research and Innovation Action “Advancing the Science for Aviation and Climate (ACACIA)”, Grant Agreement No. 875036.]
A Study on the Role of High-Low Satellite-to-Satellite Tracking (SST) in Combination with Low-Low SST for Gravity Field Estimation
Authors: Saadat Niusha , Bettadpur Srinivas , Nagel Peter
Published: February 2023

Satellite gravimetry missions continue to provide data to produce high resolution gravity models of the Earth for over 20 years. The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) exemplifies the current state-of-the-art mission architecture. GRACE-FO consists of a pair of twin satellites flying in the same orbit with an onboard laser ranging interferometer (LRI) system and GNSS receivers. The LRI is used for accurately tracking low-low satellite range change. The GNSS receivers are used for high-low SST to GNSS satellites, contributing information for satellite positioning, timing, and long-wavelength gravity field information. We present results from a numerical simulation study to assess possible variations of the high-low component of the architecture relative to the GRACE-FO configurations. Aspects of the setup such as measurement observables, measurement and bias parameterization, and noise characteristics are evaluated to fully characterize how high-low SST and its errors impact gravity field estimation. We anticipate the results to be useful in the architecture and science data analysis algorithms for future mass change missions. 
A generalised failure criterion for rooted soils
Authors: Karimzadeh Ali Akbar , Leung Anthony Kwan
Published: February 2023

Plant roots are generally known to increase soil shear strength because of mechanical root reinforcement. Because of the anisotropic root distribution in soil, the shear strength of rooted soils is stress path-dependent, which is crucial to the engineering analysis and design of the stability of vegetated soil slopes. Existing failure criteria of rooted soils, which were mostly established based on direct-shear test results, were unable to account for the strength anisotropy of rooted soils under general loading conditions. In this presentation, we will propose and derive a new generalised 3-D anisotropic failure criterion for rooted soils. The anisotropic effects of root network and soil fabric on the shear strength of rooted soils upon various effective stress paths was captured by employing of the projection of the microstructure fabric tensors of soil and root network on stress tensors. To verify the proposed model, we will present the test results of drained compression and extension triaxial tests of saturated soil samples cultivated with deep-rooted vetiver grass (Chrysopogon zizanioides L.) under different over consolidation ratios (OCR; i.e., 1 and 3) and effective confining pressures (i.e., 50, 100 and 150 kPa). We discovered that upon compression stress path, the presence of roots increased the contractive behaviour of soil in normal consolidated samples, whereas the rooted soils were more dilative than bare soil in over consolidated samples. The presence of roots increased dilative behaviour of rooted soil following extension, irrespective to OCRs, because majority of the vetiver roots were grown vertically in a direction perpendicular to that of the major principal stress, resulting in greater mobilisation of the root tensile strength. Based on the calibrated model, we showed the anisotropies of both the cohesion and friction angle of the rooted soils. We also demonstrated why most of the studies that used the direct shear apparatus as a means of testing reported that roots affected almost exclusively the cohesion but not the friction angle. Indeed, the stress paths that direct shear followed are within section I of the deviatoric plane, where the effects of soil anisotropy on friction angle are not significant.
Preliminary Results of the GMAP/SIJAQ Campaign: Remote Sensing Measurements of Air Pollution over Korea
Authors: Bae Kangho , Song Chang-Keun , Richter Andreas , Wagner Thomas , Roozendael Michel van , Lange Kezia , Boesch Tim , Ziegler Steffen , Merlaud Alexis , Park Sang Seo , Park Jong-Uk , Hong Hyunkee
Published: February 2023

GEMS (Geostationary Environmental Monitoring Spectrometer), the world’s first geostationary environmental satellite was successfully launched in February 2020 and keeps monitoring the trace gases around East Asia. For improving the GEMS retrieval algorithms and validation of the products, NIER (National Institute of Environmental Research) organized two international field campaigns in Korea: GMAP2021 (GEMS MAP of Air Pollution) and SIJAQ2022 (Satellite Integrated Joint monitoring of Air Quality), respectively in winter and summer season. In the framework of these campaigns, to fill the gap of the reference ground remote sensing observation network, additional Pandora and MAX-DOAS instruments were installed in SMA (Seoul Metropolitan Area), Ulsan, and Busan. In addition, we operated Car-DOAS and GCAS (GeoCAPE Airborne Simulator) flight measurements around the SMA and the Southeastern region to catch the detailed distribution of emission sources. Preliminary results indicate different diurnal variation patterns of NO2 columns in SMA and the Southeastern region, visible both in ground-based and GEMS data. Car-DOAS measurements show a detailed distribution of trace gases at city level and for a few days during the summer season (SIJAQ2022), Car-DOAS even caught some well-synchronized high SO2 and HCHO signals with NO2, which can be related to anthropogenic emissions around the industrial area and in the case of the SMA emission estimation measurement, nice plumes were observed along the wind direction on good meteorological condition days.
A model-based estimate of the climate and carbon cycle response to negative CO2 emissions over multi-centennial timescales
Authors: Jayakrishnan Koramanghat Unnikrishnan , Bala Govindasamy
Published: February 2023

Anthropogenic emissions of carbon dioxide since the beginning of industrialization have led to an increase in global surface temperature. This rapid increase in global surface temperature is unprecedented over the past 2000 years. The increase in frequency of natural disasters such as extreme rainfall, floods and heatwaves indicate that immediate action is required to prevent further impact of climate change. The Paris agreement targets to keep warming below 2°C above the preindustrial state, while pursuing efforts to limit the increase to 1.5°C . While climate mitigation strategies such as reducing fossil fuel emissions and deforestation are currently implemented, recent studies show that artificially removing atmospheric CO2 (negative emissions) might be necessary to achieve the targets set by the Paris agreement. Therefore, understanding the response of climate system towards artificial removal of atmospheric CO2 or equivalently negative emissions is essential.In this study, using a coupled climate and carbon cycle model, we simulate the response of the climate system to net negative emissions in 9 idealized simulations each having a positive emission phase and an equal and opposite negative emission phase such that the cumulative emissions since preindustrial period is zero in each simulation. We specifically address the following two questions: 1) For the same total emissions in the positive phase, does the timescale of emissions have any impact on the long-term response of the climate system? 2) If the timescale of emissions is the same, what is the sensitivity to the magnitude of total emissions in the positive phase? The results from our nine climate-carbon model simulations will be discussed at the meeting.
Effects of the Pacific Antarctic Circumpolar Current on the extant coccolithophore Emiliania huxleyi
Authors: Morgan Ellis , Saavedra-Pellitero Mariem , Malinverno Elisa
Published: February 2023

During the last decades, the Southern Ocean (SO) has been experiencing physical and chemical drastic changes which are affecting the distribution and composition of pelagic plankton communities. Coccolithophores (small-sized haptophyte algae) are the most prolific carbonate-producing phytoplankton group, playing a key role in biogeochemical cycles at high latitudes.In this work we investigated the biogeographical distribution and calcification patterns of the ecologically dominant species Emiliania huxleyi across a latitudinal transect in the Pacific sector of the SO (from ~40°S to ~54°S). We aimed to assess the response of E. huxleyi to steep environmental gradients across the frontal system of the Antarctic Circumpolar Current.The plankton samples were collected during International Ocean Discovery Program Expedition 383: Dynamics of Pacific Antarctic Circumpolar Current (DYNAPACC, May-July, 2019) onboard the R/V JOIDES Resolution (https://iodp.tamu.edu/scienceops/expeditions/dynamics_of_pacific_ACC.html). In situ environmental data (such as sea surface temperature, total alkalinity and pH) were measured at each sampling location.The samples were prepared and analysed at the University of Portsmouth using a combination of electron backscatter diffraction (EBSD), Scanning Electron Microscope (SEM) and light microscopy techniques.
Meteoric Ca Ion Transport From ∼80 to 300 km in the Midlatitude Nighttime Ionosphere
Authors: Jiao Jing
Published: February 2023

We report a world record of lidar profiling of metallic Ca+ ions up to 300 km in the midlatitude nighttime ionosphere during geomagnetic quiet time. Ca+ measurements (∼80–300 km) were made over Beijing (40.42°N, 116.02°E) with an Optical-Parametric-Oscillator-based lidar from March 2020 through June 2021. Main Ca+ layers (80–100 km) persist through all nights, and high-density sporadic Ca+ layers (∼100–120 km) frequently occur in summer. Thermosphere-ionosphere Ca+ (TICa+) layers (∼110–300 km) are likely formed via Ca+ uplifting from these sporadic layers. The lidar observations capture the complete evolution of TICa+ layers from onset to ending, revealing intriguing features. Concurrent ionosonde measurements show strong sporadic E layers developed before TICa+ and spread F onset. Neutral winds can partially account for observed vertical transport but enhanced electric fields are required to explain the results. Such lidar observations promise new insights into E- and F-region coupling and plasma inhomogeneities.
Warming of Tibetan Plateau and continual winter-spring drought in Southwest China in the background of global warming
Authors: Shi Huijie , Tian Rongxiang , Lou Xiangyuan , Jin Zhan
Published: February 2023

In the context of global warming, the Tibetan Plateau, as the “third pole”, is still unclear about the impact of climate warming on the climate anomalies in the surrounding areas. Using mathematical statistics and climate diagnosis, we compared the anomalies of thermal and dynamic field caused by plateau warming during winter-spring with the continuous drought events in Southwest China from 1991 to 2020. Here we show that, there is a three-year lagged correlation between the plateau climate warming and southwest China precipitation. The correlation coefficient between sensible heat and drought degree exceeds -0.498 and confidence level is greater than the 95%. The warming of the Tibetan Plateau leads to the positive vorticity change around the plateau, which strengthens the westerly circulation of the southern branch, weakens the westerly (cold) wind of the northern branch. Thus, the Southwest China is controlled by a single dry and warm air mass,  and eventually leads to continual winter-spring drought events. When the plateau warming is accompanied by the La Niña event, the drought will last longer and be stronger. The results are of  reference value for the prediction of extreme climate under the action of special terrain, and have certain significance for local disaster prevention.
Simulation of Precipitation with a Variable Characteristic Adjustment Time Scale Parameter of Deep Convection in a Global AGCM
Authors: Wang Minghao , Wang Lanning
Published: February 2023

The characteristic adjustment time scale τ is always defined as the time allowed for dissipation of Convective Available Potential Energy (CAPE) in convective parameterization schemes. Previous studies indicate that, in the cloud ensemble, τ is one of the most important parameters that have  the greatest influences on the global mean precipitation. Some research work has improved the Kain–Fritsch scheme in the regional model to realize the variable parameters. In the global model, some studies have used machine learning methods to optimize the parameters of the deep convection trigger function. However, changing constant parameters into variable parameters in the global model has not been explored. In our study, the Zhang-McFarlane (ZM) deep convection scheme is improved to realize the variable characteristic adjustment time scale parameter, so as to reduce the precipitation deviation in a global model. In the ZM deep convection scheme, τ is usually the default constant. While in this paper, we use CAPE to modulate τ and propose a calculation formula of τ. In the region where the mean precipitation amount bias is improved, the new scheme mainly increases the deep convective precipitation and reduces the large-scale and shallow convective precipitation. The modified scheme significantly improves the simulation of precipitation over the eastern equatorial Pacific Ocean and some steep terrain regions. The root mean square error of the mean precipitation amount over the eastern equatorial Pacific Ocean and the central Indo-Pacific Warm Pool in boreal summer is reduced after the new scheme is adopted in a global model with the horizontal resolution of 1° longitude and 1° latitude. Moreover, the simulations of precipitation over the Tibet Plateau and South America are also improved. The new scheme reduces the frequency of deep convective precipitation and increases the amount of deep convective precipitation each time.
Comparing quasi-3D soil moisture derived from electromagnetic induction with 1D moisture sensors and correlation to barley yield in variable duplex soil
Authors: Shaukat Hira , Flower Ken , Leopold Matthias
Published: February 2023

Farms in Western Australia (WA) are highly variable in soil texture and water retention capacity; therefore, spatial information of soil moisture status in the field is important for crop management. In practice, farmers often rely on point sensors to determine soil moisture in their fields for crop planning. The limitation of point measurements to account for spatial variability highlights the need to develop methods to assess soil moisture across variable broadacre fields. This information could be used for more effective site-specific crop management practices. In this study, we used a mobile nonintrusive electromagnetic induction (EMI) sensor to map soil apparent electrical conductivity (ECa) and to predict soil moisture levels across the field at three depths (0 – 0.5, 0.5 – 0.8 and 0.8 – 1.6m). The predicted soil moisture was compared with the point measurements of soil moisture sensors and soil samples. The inverted electrical conductivity (EC) from EMI surveys was converted into soil moisture using calibrations between electrical resistivity tomography (ERT) to volumetric moisture, which were developed for the different soil textural classes of the field, with R2 of 0.97 to 0.99. The soil moisture variability of the field was also compared with the spatial distribution of 2019 barley yield production. No significant difference was found between the EMI estimated soil moisture values and the point moisture measurements, as well as moisture extracted from soil samples for 0 – 0.5m and 0.5 – 0.8 m depths with Pearson R values of 0.62 and 0.73 respectively. Barley yield was not correlated with mapped soil moisture or soil texture, which may be due to relatively high initial moisture levels following two years of fallow rotation. This study successfully demonstrated spatial soil moisture estimation using EMI sensor in a field with horizontally and vertically variable soil texture.
A national flood awareness system for ungauged catchments in complex topography for Aoetearoa New Zealand.
Authors: Cattoen Celine , Conway Jono , Fedaeff Nava , Blackett Paula , Shankar Ude , Steinmetz Tilmann , Carey-Smith Trevor , Moore Stuart , Measures Richard
Published: February 2023

Floods cause over $40 Billion of damage worldwide every year. In Aotearoa New Zealand, it is the most frequent natural disaster, with an average annual cost of NZ$100 million for residential properties. Effectively forecasting and communicating flood hazards at national or continental scales is critical to reducing the impacts of flooding. However, developing national-scale river flow forecasting systems remains a challenge due to the predominance of ungauged catchments in often complex and steep terrain. We will present the model development, communication, and evaluation of New Zealand’s first national flood awareness system prototype, the Aotearoa Flood Awareness System, AFAS (Cattoën et al., 2022). To produce river forecasts, a high-resolution convective-scale atmospheric model drives an uncalibrated and semi-distributed hydrological model. The system includes statistical perturbations in rainfall, soil moisture and baseflow to generate a 50-member ensemble. We implemented a relative flow and flood exceedance threshold framework to evaluate hourly forecasts across six categories from below normal to extremely high. We assessed forecast performance categorically against observations, for a 2.5-year reforecast period, at 272 flow sites nationwide, up to 48 hours ahead. AFAS produces skilful streamflow forecasts in catchments with complex topography, even with operational delays ingesting observations. We explored a novel approach to river forecast communication using daily videos and will present feedback gathered from stakeholder workshops and semi-structured interviews. Finally, we will share our experience providing real-time AFAS forecast information during flood responses on the West Coast in 2021 and 2022. AFAS appears to be the first river forecasting system to produce public-friendly videos to communicate streamflow forecasts in their topographical context. Further development of AFAS would benefit from a federated approach across national and regional agencies, including sharing real time weather observations, forecasting tools and expertise.Cattoën, C., Conway, J., Fedaeff, N., Lagrava, D., Blackett, P., Montgomery, K., Shankar, U., Carey-Smith, T., Moore, S., Mari, A., Steinmetz, T., & Dean, S. (2022). A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand. Journal of Flood Risk Management, e12864. https://doi.org/10.1111/jfr3.12864