bluuebunny/crossref_metadata_2025 huggingface dataset:
Drivers for different behaviors in storm-time thermospheric O/N2 ratio and nitric oxide density
Authors: Zhang Yongliang , Wang Wenbin , Paxton Larry
Published: March 2024

Geomagnetic storms lead to significant depletion/enhancement in O/N2 column density and enhancement in nitric oxide (NO) in the thermosphere.  The O/N2 depletion is generally anti-correlated with NO enhancement on a global scale. However, the NO enhancement often extends beyond the equatorward edge of O/N2 depletion in latitude and/or the range of O/N2 depletion in longitude on a local scale. These behaviors are most likely driven by the storm-time equatorward wind that brings the O/N2 depleted and NO enhanced air from high to low latitudes, as well as zonal wind perturbations. On the other hand, the equatorward wind also depends on altitudes. Note that the peak NO density locates at an altitude around 110 km while the O/N2 column density is mostly contributed by local O andN2 density around 140 km and above. The different behaviors between NO and O/N2 are likely due to the altitude variations of the meridional winds during storms as revealed by TIEGCM simulations. The downward advection by vertical winds associated with storm-time meridional circulation perturbations may also contribute to the difference.
Optimal Control Model for Managing Land Subsidence and GHG Emissions in Peatlands
Authors: Verhoeven Dewy
Published: March 2024

Peatlands are crucial carbon reservoirs, containing one-third of global soil carbon. Many peatlands undergo extensive drainage for agriculture, causing land subsidence and substantial greenhouse gas (GHG) emissions. Peatland drainage contributes approximately 5% to global anthropogenic GHG emissions. Rewetting is considered an effective climate and subsidence mitigation strategy, strongly reducing CO2 emissions. However, this comes at the cost of reduced agricultural productivity and can (temporarily) increase methane emissions. This paper addresses these trade-offs by developing a bio-economic optimal control model for managing subsiding peatlands, incorporating social costs and emission impacts.Our model integrates water level management, subsidence dynamics, and monetization of effects on agricultural profits, management costs, and GHG emissions. Through numerical simulations, the model optimizes the groundwater level pathway (g(t)) over time achieved through drainage, maximizing net societal benefits. We model the relation between drainage intensity and the peat thickness (S(t)), and monetize the impacts on agricultural profits (y(S, g, t)), water management costs (m(g, t)), and climate costs (c(S, g, t)), thus considering the objective function:Subject to land subsidence:Where t ∈ [0, T ] represents the exploitation period of peat before full rewetting.We apply our model to the Dutch peat meadows, which suffer from severe subsidence and are responsible for 3% of Dutch yearly GHG emissions. We parametrize our model based on empirical data found in literature, existing physical subsidence models and peatland emission factors. For a welfare analysis, we compare the optimal pathway to a Business-as-Usual (BAU) scenario in which financial net benefits are maximized, ignoring climate costs.Baseline simulations for a typical peatland plot indicate that it is socially optimal to lower drainage intensity from year 0 and reduce the exploitation period before full rewetting, compared to the BAU. Sensitivity analysis reveals that optimal pathways are particularly sensitive to changes in agricultural prices and marginal damage costs of carbon. The net social benefit of adopting the optimal drainage path over BAU is around € 46,800 ha−1 in the baseline, growing considerably with lower discount rates and higher marginal cost of carbon. Using a spatial soil and subsidence data set of Dutch peat meadows, we are able to analyse spatial differences in optimal pathways and identify key areas where (quick) rewetting would be most beneficial.This research underscores the efficacy of a bio-economic optimal control model in designing sustainable subsidence and climate mitigation measures for peatlands. Results suggest that (partial) rewetting of peatlands yields significant long-term social benefits, even with reduced agricultural productivity.
Multiscale matters: when coupling across multiple scales drives the dynamics of solar system plasmas
Authors: Chapman Sandra
Published: March 2024

The sun, solar wind and magnetospheres exhibit non-linear processes that can couple across a broad range of space and time scales. These multiscale processes can be central to the dynamics of far from equilibrium plasmas, where collisionless processes dominate. This talk offers highlights from two interconnected approaches to advancing our understanding of multi-scale processes in solar system plasmas.From the plasma physics: If sufficient simplifications can be made, we can study the plasma dynamics from first principles. The non-linear scattering and acceleration of energetic particles in current sheets, by wave particle interactions, and in shocks, can be approached from non self-consistent single particle dynamics allowing the full non-linear physics, including low-dimensional chaos, to be considered. The physics of shocks, reconnection, and its interplay with turbulence can be approached by fully kinetic self-consistent simulations, albeit with restrictions on physical dimension and the range of scales resolved. If bursty energy and momentum transport is an emergent process, then it can be captured by reduced models.From the data: The full dynamics is revealed in all its richness in observations. A wealth of in-situ and remote observations are available from the fastest physical timescales of interest to across multiple solar cycles. In principle, these afford the study of specific physical process such as reconnection and turbulence, and system-scale processes such as the dynamics of magnetospheres, all of which are fully multiscale and non-linear. In practice, determining the physics from observations relies upon establishing robust, reproducible patterns and relationships from multipoint data in these inhomogeneously sampled, non time-stationary systems. As well as providing fundamental physical insights, these can deliver quantitative estimates of space weather risk.
Diabatic Amplification of Atmospheric River Intensity by Marine Heatwaves: Multi-Scale Air-Sea Interaction and Implications for Marine Heatwave Dissipation
Authors: Renkl Christoph , Seo Hyodae , Beaudin Élise , Wilson Anthony , Miller Art , Di Lorenzo Emanuele
Published: March 2024

The climate along the US West Coast is profoundly affected by the extratropical ocean and air-sea interaction near the coast, influencing moisture transport and valuable precipitation that play an important role in agricultural and water resource management efforts. On a basin scale, seasonal to interannual anomalies in the atmospheric circulation can create persistent upper-ocean temperature anomalies known as marine heatwaves (MHWs). These anomalous SST conditions have direct impact on air-sea fluxes, thereby influencing diabatic processes associated with synoptic-scale weather patterns, such as atmospheric rivers (ARs). Given the heat and moisture pickup by the ARs from the oceans, these multi-scale MHW-AR interactions may also represent a potential mechanism for dissipation of MHWs. This study examines diabatic multi-scale coupled air-sea interaction processes between persistent MHWs and synoptic-scale ARs, and evaluate their downstream effects on the coastal and inland climate.Here, we present a comprehensive analysis based on observations and high-resolution, large-ensemble regional coupled model simulations targeting a series of landfalling ARs that interacted with warm SST anomalies during the Northeast Pacific MHW event in winter 2014/2015. Sensitivity simulations are conducted where various aspects of the observed MHW feature are removed from the ocean component of the coupled model to quantify the diabatic modification of the AR moisture and energy budgets. Our results show that MHWs exert diabatic forcing of the lower troposphere via enhanced latent heat flux from the ocean to the atmosphere and an associated increase in evaporation. This ultimately represents a nontrivial moisture source leading to an amplification of ARs indicated by a robust increase in rainfall intensity. Furthermore, the model results suggest noticeable shifts in the precise landfalling locations of the AR, the statistical significance of which is being assessed via ongoing ensemble simulations. The implications of MHW dissipation arising from the diabatic interaction between ARs and MHW will be discussed.
Decametric-scale buffering of climate extremes in forest understory within a riparian microrefugia: the key role of microtopography
Authors: Ogée Jerome , Walbott Marion , Barbeta Adrià , Corcket Emmanuel , Brunet Yves
Published: March 2024

Riparian corridors often act as low-land climate refugia for temperate tree species in their southern distribution range. A plausible mechanism is the buffering of regional climate extremes by local physiographic and biotic factors. To test this idea, we deployed over 3 years a network of 39 microclimate sensors along the Ciron river, a refugia for European beech (Fagus sylvatica) in southwestern France. Sensor locations spread along the main geomorphological landscapes, vegetation types and microtopographic situations. Across the whole network, canopy gap fraction was the main predictor for spatial microclimatic variations. Two landscape features (elevation above the river and woodland fraction within a 300m radius) were also strong predictors, while geographical variables such as altitude or distance to the river mouth were marginally important, and mainly contributed to explain offsets in winter and spring minimum temperature. However, within the riparian forest only (canopy gap fraction < 25%, distance to the river < 150m), variations of up to -4°C and +15% in summertime daily maximum air temperature and minimum relative humidity, respectively, were still found from the plateau to the cooler, moister river banks, only ~5-10m below. Elevation above the river was then identified as the main predictor, and explained the marked variations from the plateau to the banks much better than canopy gap fraction. The microclimate measured near the river is as cool but moister than the macroclimate encountered at 700-1000m asl further east in F. sylvatica's main distribution range. Indeed, at all locations, we found that air relative humidity was much higher than expected from a temperature-only effect, suggesting that extra moisture is brought by the river. Such strong microclimatic influence of fine-scale topography and river moisture may well explain the distribution of beech trees in this riparian refugium, restricted to the river gorges where microtopographic variations are the strongest.
Estimating core dynamics via the assimilation of magnetic field models into numerical dynamos
Authors: Gwirtz Kyle , Kuang Weijia , Sabaka Terence
Published: March 2024

A significant portion of the Earth’s observed magnetic field is sustained by fluid motion in the planet’s outer core (geodynamo) and varies over time. Records of the past magnetic field come from a variety of sources including, paleo- and archaeomagnetic data. In the modern era, satellite-based observations from missions such as SWARM, have led to a new level of spatial and temporal resolution in our knowledge of the magnetic field. Such observations of the field’s secular variation (SV) can provide a unique window into the deep interior of the Earth. However, understanding the origins and implications of observed SV calls for connecting data to models of Earth’s core dynamics.Over the last 10-15 years, there has been increasing interest in using data assimilation (DA) to connect numerical dynamo simulations with magnetic field observations. DA is a general term for methods by which one can produce a “weighted combination” of numerical models and observations, to estimate a system’s overall state. This approach is widely used in applications such as numerical weather prediction, where DA is used to, for example, determine initial conditions for forecasts.We present recent work in the development of DA as a tool for understanding the Earth’s deep interior, using NASA’s Geomagnetic Ensemble Modeling System (GEMS). In simple terms, we “nudge” an ensemble of numerical geodynamo model runs toward observed magnetic field variations according to an Ensemble Kalman Filter (EnKF) framework. This process has the potential to recover information about dynamics which cannot be directly observed, such as the fluid flow and magnetic field deep within the interior. We highlight recently improved capabilities of GEMS, investigate its ability to constrain the core state, and discuss the impact of SWARM data on this work.
Shoaled glacial Atlantic Ocean Circulation despite vigorous tidal Dissipation: Vertical Stratification matters
Authors: Chen Yugeng , Song Pengyang , Chen Xianyao , Lohmann Gerrit
Published: March 2024

During the Last Glacial Maximum (LGM), tidal dissipation was about three times higher than today, which could have led to a considerable increase in vertical mixing. This would enhance the glacial Atlantic Meridional Overturning Circulation (AMOC), contradicting the shoaled AMOC as indicated by paleo proxies. Here, we conduct ocean model simulations to investigate the impact of background climate conditions and tidal mixing on the AMOC during LGM. Our results show that the shoaled glacial AMOC is mainly due to strong glacial ocean stratification and enhanced glacial Antarctic Bottom Water (AABW), irrespective of enhanced tidal dissipation. Enhanced tides only play an important role if they are applied to a present background climate with relatively weak ocean stratification. Given the critical role of AMOC in (de-)glacial climate evolution, our results highlight the complex interactions of ocean stratification and tidal dissipation that have been neglected so far.
A Geodetic Drought Index Driven by Hydrologic Loading Estimates Calculated from Three-Dimensional GPS Displacements  
Authors: Young Zachary M. , Martens Hilary R. , Hoylman Zachary H. , Gardner W. Payton
Published: March 2024

During periods of drought, quantifying the intensity of water loss within hydrologic reservoirs, both on and below the surface, is critical to sustain water resources. Drought intensity is typically characterized using drought indices which are driven by meteorologic observations, such as precipitation. These drought indices provide good insight into the quantity of water entering the hydrologic system, however, they are unable to quantify the amount of water retained in a watershed or the amount lost due to runoff and evapotranspiration. We address this by leveraging the sensitivity of three-dimensional Global Positioning System displacements to local and regional hydrologic-storage fluctuations, and produce a new geodetic drought index (GDI), derived from estimated hydrologic-storage deviations, to directly characterize hydrologic storage anomalies. The GDI is derived comparably to the Standardized Precipitation Evapotranspiration Index such that it may be easily incorporated into current drought management workflows. We directly compare the GDI to hydrologic observations within California and find strong associations between specific time scales of the GDI and groundwater well, artificial-reservoir storage, and stream discharge observations. The GDI is most sensitive to groundwater, exhibiting a correlation coefficient of 0.87 at the 3-month time scale. Both artificial-reservoir storage and stream discharge exhibit peak correlation coefficients when considering the 1-month GDI, at 0.81 and 0.47 respectively. No relationship is observed with soil moisture observations. The correlation coefficients decline rapidly away from the optimal time scale, indicating the 1- and 3-month GDI are strong predictors of hydrologic variation within California. In addition to capturing long-term trends, rapid changes in the GDI initiate during clusters of large atmospheric-river events that closely mirror fluctuations in the hydrologic observations. The GDI provides an opportunity to improve hydrologic models for drought-management and to advance our understanding of the water cycle. 
Calcareous nannofossils biostratigraphy and paleoecology of the Miocene Qom Formation (Burdigalian, Central Iran) 
Authors: Sharifi-Yazdi Masoud , Wagreich Michael , Granero Ordoñez Paula
Published: March 2024

During the Early Miocene a global cooler interval was followed by warmer paleoclimate conditions. At the end of the Burdigalian, the Miocene Climatic Optimum (MCO) occurred and brought about global warming and resulting changes in paleoecology and paleoceanography. The Qom Basin (Iran) was situated between the Mediterranean Sea and Indian Ocean and is considered as part of the main Tethyan Seaway, established from Oligocene to Miocene times. In this study, two calcareous nannofossil biozones are recognized in the e-member of the Qom Formation (Burdigalian), the NN3 (zone Sphenolithus belemnos) and NN4 (zone Helicosphaera amplipareta) zones, respective. The modifications in paleoecology and climatic conditions played a vital function in the assemblage structure and the frequency of the calcareous nannofossils during the Burdigalian. From the early to the middle Burdigalian, paleoecologic conditions in the Qom Basin changed from oligotrophic with a warm climate to eutrophic, accompanied by an increase in productivity in the basin, coincided with a cooler climate and inferred upwelling conditions. In contrast, in the late Burdigalian, mesotrophic to oligotrophic conditions were dominant in the basin, affected by the predominance of the MCO and global warming. Warming impacted nutrient availability and salinity, and changes in circulation patterns in the Tethyan Seaway because of the stepwise tectonic closure of the Qom Basin. The paleoceanography and tectonic activity thanks to alteration in the connectivity between the Tethyan Seaway and other basins influenced the calcareous nannofossils assemblages.Keywords: Miocene Climatic Optimum, Calcareous nannofossils, Qom Formation, Paleoecology, Burdigalian
Using meteorological reanalysis to identify weather conditions for classifying atmospheric electricity data 
Authors: Mkrtchyan Hripsime , Harrison Giles , Nicoll Keri
Published: March 2024

Atmospheric electricity Potential Gradient (PG) data has typically been classified by local weather conditions, such as by identifying data recorded during “fair weather” (FW) or in the absence of rainfall “no hydrometeors” (NH), to try and obtain globally representative values. In general, this approach is essential in obtaining global atmospheric circuit (GEC) signals. The weather information needed to do this is, however, only available from some of the sites providing atmospheric electricity measurements. For other sites, meteorological reanalysis – of which there are many products available, spanning different times and scales - may provide a data source for such classification of PG data. This study investigates the integration of ERA5 meteorological reanalysis data to identify FW and NH conditions and improves the quality of data used in long-term atmospheric electricity studies.  

Initial findings investigating the meteorological quantities show a strong correlation between wind speed, total cloud coverage and total precipitation from ERA5 and observed ground-based measurements at the Eskdalemuir and Lerwick sites. This is to be applied to classifying past atmospheric electricity data, specifically of the hourly potential gradient (PG), which were obtained at the Lerwick observatory from 1925 to 1984, and Eskdalemuir observatory, which made atmospheric electricity measurements from 1911-1981 (Harrison & Riddick, 2022; Märcz & Harrison, 2003). 

Identified criteria from ERA5 which best match for FW and NH conditions are implemented in historical data from the Lerwick and Eskdalemuir observatories, enhancing the reliability of past studies which is important for atmospheric electricity analyses. This supports the potential of ERA5 data for providing information to identify FW and NH conditions. From this, we are evaluating a range of methods to use the meteorological reanalysis, with the aim of recovering representative FW data at sites lacking meteorological measurements. 
Rapidly forming submarine craters and massive ice outcrops along the Arctic shelf edge: by-products of subsea permafrost degradation
Authors: Paull Charles K. , Hong Jong Kuk , Caress David W. , Gwiazda Roberto , Kim Ji-Hoon , Duchesne Mathieu J. , Lundsten Eve , Paduan Jennifer B. , Rhee Tae Siek , Jin Young Keun , Brake Virginia , Obelcz Jeffrey , Walton Maureen
Published: March 2024

Substantial morphological changes are rapidly occurring along the Canadian Arctic shelf edge (Paull et al., 2022, PNAS). During a 2022 IBRV Araon cruise, autonomous underwater vehicle mapping surveys identified several new craters that formed between 2019 and 2022. Five multibeam bathymetric mapping surveys, each partially covering a 15 km2 study area between 120 and 200 mwd have now been conducted over a 12-year time period. These repeat surveys reveal 65 new depressions developed averaging 6.5 m deep and reaching up to 30 m deep. Remotely operated vehicle investigations also discovered outcrops of massive ice exposed on the flanks of the newest craters. This ice is not believed to be relic permafrost formed during Pleistocene sea-level low-stands because the host sediments were deposited in a submarine setting. The low porewater salinity and light isotopic compositions in the meltwater of ice samples from sediment cores indicate brackish waters reflecting a meteoric source are discharging and freezing in this area. The ascending brackish groundwater is likely derived from melting relict permafrost under the shelf. The ~ -1.4°C bottom water temperatures provide conditions appropriate for freezing brackish porewaters within the near seafloor sediments. Conditions appropriate for the melting of ice also exist nearby where ice is in contact with seawater or warmed by ascending groundwater. Small variations in either temperature or salinity, over time, can shift equilibrium conditions of ice formation and degradation, which leads to repetitive freezing and thawing of ascending brackish groundwater and the development of wide-spread ice layers in the near seafloor sediments. These conditions have produced a dramatic submarine thermokarst morphology riddled with multi-aged depressions captured in the repeat mapping surveys. These findings suggest that the distribution of submarine permafrost ice should be reassessed as it may include extensive areas where ice formed during the Holocene where groundwaters discharge at sub-zero temperatures, in addition to relict Pleistocene permafrost.
Art and music as a teaching aid for STEM subjects
Authors: Heron Philip , Crameri Fabio , Williams Jamie , Lewis-Nimako Janeesa , Narayan Sophia , Hashemi Sara , Canaletti Elisabetta , Osowski Kiona , Harrison Dalton , Rantanen Rosa
Published: March 2024

Science, technology, engineering, and math (STEM) subjects have historically struggled to be inclusive and accessible to students from diverse backgrounds. Furthermore, STEM subjects have often been rigid in their teaching structure, creating barriers to education for students with more complex learning needs. Recently, there has been an increased need for compassionate pedagogy and adaptive education practices to provide multi-modal learning experiences. Our STEM outreach course, Think Like A Scientist, has been running in a number of English prisons since 2019, and started in Canada in 2023. Our students in prison often have diverse learning needs and the classroom presents numerous barriers (sensory, communication, processing, and regulation). This particularly impacts those considered with forms of neurodivergence (e.g., autism, ADHD, OCD, dyslexia, etc). In our teaching in prison, we have been conscious of creating different educational access points that is not focussed on rote learning and reading text (which some students struggle with). In particular, we have been using creative practices, including art, poetry and music, as a teaching aid for geoscience subjects such as climate change.In this submission, we outline how we have created a collaborative space between artist and student to co-create unique art and music that stimulates learning and engagement. Although our outreach programme is tailored to the restrictive prison environment, the application of its core principles to education are fundamental EDI practices that could be beneficial to a wide audience. Our work aims to increase educational engagement for students under the neurodivergent umbrella, fostering a classroom environment that is inclusive and accessible to all.  
Sustained upward discharge of relict high-salinity groundwater through salt marsh tidal creeks
Authors: Zhan Lucheng , Xin Pei , Chen Jiansheng , Chen Xiaogang , Li Ling
Published: March 2024

Salt marshes are fine-grained ecosystems widely distributed in the intertidal zone along global coastlines. Recent studies proved that submarine groundwater discharge (SGD) in salt marshes exports abundant nutrients and carbon supporting marine productivity and carbon sequestration in the ocean. However, due to our limited knowledge of groundwater discharge processes in these low-permeability systems, the accurate quantification of SGD-derived fluxes remains a great challenge. In a salt marsh system in East China, we found numerous high-salinity springs discharging from the bottom of tidal creeks. To determine their origin and trajectory, multiple field investigation methods including time-series thermal monitoring, isotope signatures and high-resolution electrical resistivity tomography were combined. Results suggest that these springs originate deep from the ancient relict marine water in the aquifer and keep discharging even during high tide. Such process represents a long-term re-distribution of the ancient marine water trapped in the unconfined aquifer. This spring-derived groundwater flow indicates a hidden SGD pathway in salt marshes, which has significant implications for studies concerning SGD-derived fluxes in similar multi-aquifer-aquitard coastal systems. These findings shed new light on the complex SGD processes in low-permeability coastal systems, while future studies are still required to further determine its driving forces and make quantitative assessments.
Detection of orbital signals in the sedimentary record through stochastic statistical modeling
Authors: Wang Meng , Li Mingsong , Hajek Elizabeth A. , Kemp David B. , Wu Yujing , Zhu Hanyu , Jin Zhijun
Published: March 2024

The preservation of orbital signals in sedimentary records, a crucial aspect for the reliability of astronomical time scales, has been insufficiently explored, presenting challenges in interpretation. In this study, we focus on the effect of inconsistent sedimentation rates on the preservation of these orbital signals from a modeling perspective. We delve into how inconsistent sedimentation rates influence the retention of these orbital signals. Employing stochastic statistical models, our research simulates diverse sedimentary environments, we show that 405-kyr eccentricity tuning is the most reliable approach for constructing ATS among different tuning strategies, particularly in environments characterized by high energy conditions and unsteady sedimentation such as fluvial or deltaic settings. This discovery holds substantial importance in refining geological time scales. We introduce an innovative approach to evaluate sedimentation rates within these records. Our study demonstrates the robustness of the cyclostratigraphic method and deepens our understanding of the preservation of sedimentary records, thereby enriching our grasp of Earth's intricate geological past.
Combined Radar Quality Index for Quantitative Precipitation Estimation of Heavy Rainfall Events
Authors: Zhang Yang , Liu Liping , Wen Hao
Published: March 2024

For quantitative precipitation estimation (QPE) based on polarimetric radar (PR) and rain gauges (RGs), the quality of the radar data is crucial for estimation accuracy. A combined radar quality index (CRQI) is proposed to represent the quality of the radar data used for QPE and an algorithm that uses CRQI to improve the QPE performance. Nine heavy rainfall events that occurred in Guangdong Province, China, were used to evaluate the QPE performance in five contrast tests. The QPE performance was evaluated in terms of the overall statistics, spatial distribution, near real-time statistics, and microphysics. CRQI was used to identify good-quality data pairs (i.e., PR-based QPE and RG observation) for correcting estimators (i.e., relationships between the rainfall rate and the PR parameters) in real-time. The PR-based QPE performance was improved because estimators were corrected according to variations in the drop size distribution, especially for data corresponding to 1.1 mm < average Dm < 1.4 mm, and 4 < average log10 Nw < 4.5. Some underestimations caused by the beam broadening effect, excessive beam height, and partial beam blockages, which could not be mitigated by traditional algorithms, were significantly mitigated by the proposed algorithm using CRQI. The proposed algorithm reduced the root mean square error by 17.5% for all heavy rainfall events, which included three precipitation types: convective precipitation (very heavy rainfall), squall line (huge raindrops), and stratocumulus precipitation (small but dense raindrops). Although the best QPE performance was observed for stratocumulus precipitation, the biggest improvement in performance with the proposed algorithm was observed for the squall line.
Influences of urbanization on an afternoon heavy rainfall event over the Yangtze River Delta region in East China
Authors: Jiang Xiaoling , Zhang Da-Lin , Luo Yali
Published: March 2024

This study examines the urban impacts associated with a developed city belt on generating an afternoon heavy rainfall event over a coastal developing city that is 70–100 km downwind from the city belt over the Yangtze River Delta region. Observational analyses show pronounced urban heat island (UHI) effects along the upstream city belt prior to convection initiation (CI). A series of cloud-permitting model simulations with the finest grid spacing of 1 km are performed to examine the impacts of urbanization on CI and the subsequent heavy rainfall event. Results reveal the generation of warm anomalies and low-level convergence in the planetary boundary layer along the upstream city belt, thereby inducing upward motion for CI. The southwesterly flows of the monsoonal warm-moist air, enhanced by the UHI effects along the city belt, allow the development of convective cells along the belt. Some of the cells merge during their downstream propagation, promoting to the ultimate generation of the distinct heavy rainfall centers in favor of local convective clusters over the coastal city where atmospheric columns are more moist and potentially unstable under the influences of sea breezes. Sensitivity simulations show small contribution of the downstream city but more influences from the upstream city belt on the heavy rainfall event. The above findings help elucidate how the UHI effects could assist the CI in a weak-gradient environment, and explain why urbanization can contribute to increased downwind mean and extreme precipitation under the influences of favorable regional forcing conditions. These findings have been published in Monthly Weather Review.
HIWIND Balloon and Antarctica Jang Bogo FPI High Latitude Conjugate Thermospheric Wind Observations and Simulations
Authors: Wu Qian , Lin Dong , Wang Wenbin , Qian Liying , Jee Geohwa , Lee Changsup , Kim Jeong-han
Published: March 2024

Using the HIWIND balloon and Antarctic Jang Bogo station high latitude conjugate observations of the thermospheric winds we investigate the seasonal and hemispheric differences between the northern and southern hemispheres in June 2018.   We found that the summer (northern) hemisphere dayside meridional winds have a double hump feature, whereas in the winter (southern) hemisphere the dayside meridional winds have a single hump feature.   We attribute that to stronger summer, perhaps, northern hemisphere cusp heating.   We also compared the observation with NCAR TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation Model) and GTR (GAMERA TIEGCM RCM) models. The TIEGCM reproduced the double hump feature because of added cusp heating.    The summer hemisphere has stronger anti-sunward winds.  This is the first time we have very high latitude conjugate thermospheric wind observations.   
Super El Niño: A product of three-ocean interactions 
Authors: Wang Chunzai , Wang Jiazhen , Fan Hanjie
Published: March 2024

El Niño, the largest climate phenomenon on Earth, profoundly influences global climate, weather, ecosystems, and human societies. Super (or extreme) El Niño, in particular, has a significant impact on climate and extreme weather events, but its formation mechanism remains unknown. This presentation utilizes observations, climate model outputs, and coupled model experiments to demonstrate that interactions among the tropical Pacific, Indian, and Atlantic Oceans contribute to the development of super El Niño. The early onset of El Niño imparts sufficient strength in the summer and fall to trigger the Atlantic Niña and Indian Ocean dipole. Subsequently, the Atlantic Niña and Indian Ocean dipole alternately generate additional westerly wind anomalies over the equatorial western-central Pacific, reinforcing El Niño through the Bjerknes feedback and leading to the emergence of super El Niño. This novel mechanism is termed the Indo-Atlantic booster. The findings emphasize super El Niño as a product of three interactions, suggesting that incorporating both the Indian and Atlantic Oceans and their teleconnections with the Pacific will significantly enhance predictions of super El Niño and climate.
Spatio-Temporal Imaging of Instability and Transport of Pickering Nanodroplets in Porous Media
Authors: Ding Boxin , Ahmadi Seyedeh Hannaneh , Bryant Steven , Kantzas Apostolos
Published: March 2024

Featuring a large specific surface area with associated high reactivity, nanomaterials in various morphologies are ideal candidates for improved oil recovery (IOR), enhanced geothermal systems (EGS) and carbon capture utilization and storage (CCUS).  Encapsulation of solid nanomaterials within an oil-in-water (O/W) emulsion (i.e., Pickering emulsion) has been employed to prevent the aggregation and deposition of the nanomaterials in subsurface reservoirs in recent decades. Here, the dispersed phase droplets were decreased to nanoscale through a utilizable procedure. These nanodroplets were stabilized solely by polymer-coated magnetic iron oxide nanoparticles. Low-field NMR and X-ray CT were employed to constantly monitor the stability of Pickering nanoemulsions until phase separation. The polydisperse nanoemulsions are more easily separated due to the severely inhomogeneous chemical potentials of the emulsion droplets. Experimental and theoretical modeling results reveal that the Ostwald ripening is the main instability mechanism for nanoemulsions due to the very small droplets associated with a high surface area. The insolubility of long-chain hydrocarbons in water acts as a kinetic barrier to Ostwald ripening, making those nanoemulsions, both the Pickering and Classical (which is formed only by polymer) ones, inherently stable to Ostwald ripening. The transport and retention of the Pickering nanodroplets in porous media is examined by X-ray CT imaging. Accordingly, in-situ transport of the nanoemulsions in a water-saturated sandpack was quantified spatiotemporally through X-ray CT. Effluents were collected and analyzed to further comprehend the nanoemulsion displacement and retention in porous media. Experimental results demonstrate that accumulation and retention of the nanodroplets in porous media are stimulated by ionic strength, nanodroplet size distribution, and nanoparticle wettability. Three transport modes in porous media (flow through with minimal retention, migration of accumulated nanodroplets, and retention of accumulated nanodroplets) can be achieved through carefully designing the nanoemulsion system.These findings shed light on the fundamental understanding of the (nano-)colloidal dispersions transport in porous media and provide implications for IOR, EGS, and CCUS.
Evaluation of CMIP6 model simulations of PM2.5 and its components over China
Authors: Ren Fangxuan , Lin Jintai , Adeniran Jamiu A. , Wang Jingxu , Martin Randall V. , van Donkelaar Aaron , Hammer Melanie S. , Horowitz Larry W. , Turnock Steven T. , Oshima Naga , Zhang Jie , Bauer Susanne , Tsigaridis Kostas , Seland Øyvind , Nabat Pierre , Neubauer David , Strand Gary , van Noije Twan , Le Sager Philippe , Takemura Toshihiko ,   ACM Group
Published: March 2024

Earth system models (ESMs) participating in the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) simulate various components of fine particulate matter (PM2.5) as major climate forcers. Yet the model performance for PM2.5 components remains little evaluated due in part to lack of observational data. Here, we evaluate near-surface concentrations of PM2.5 and its five main components over China as simulated by fourteen CMIP6 models, including organic carbon (OC, available in 14 models), black carbon (BC, 14 models), sulfate (14 models), nitrate (4 models), and ammonium (5 models). For this purpose, we collect observational data between 2000 and 2014 from a satellite-based dataset for total PM2.5 and from 2469 measurement records in the literature for PM2.5 components. Seven models output total PM2.5 concentrations, and they all underestimate the observed total PM2.5 over eastern China, with GFDL-ESM4 (–1.5%) and MPI-ESM-1-2-HAM (–1.1%) exhibiting the smallest biases averaged over the whole country. The other seven models, for which we recalculate total PM2.5 from the available components output, underestimate the total PM2.5 concentrations, partly because of the missing model representations of nitrate and ammonium. Concentrations of the five individual components are underestimated in almost all models, except that sulfate is overestimated in MPI-ESM-1-2-HAM by 12.6% and in MRI-ESM2-0 by 24.5%. The underestimation is the largest for OC (by –71.2% to –37.8% across the 14 models) and the smallest for BC (–47.9% to –12.1%). The multi-model mean (MMM) reproduces fairly well the observed spatial pattern for OC (R = 0.51), sulfate (R = 0.57), nitrate (R = 0.70) and ammonium (R = 0.75), yet the agreement is poorer for BC (R = 0.39). The varying performances of ESMs on total PM2.5 and its components have important implications for the modeled magnitude and spatial pattern of aerosol radiative forcing.
Subseasonal forecast of the MJO over Tropical America
Authors: Lazcano Luis , Dominguez Christian
Published: March 2024

The Intraseasonal Oscillation (ISO) is commonly divided into two oscillations: the Madden-Julian Oscillation (MJO), which commonly occurs from November to April in winter, and the Boreal Summer Intraseasonal Oscillation (BSISO), which occurs from May to October. Recent studies have classified these two modes into different types using cluster analysis. Here, we analyze the oceanic and atmospheric variables from the reanalysis ERA5 to determine the influence of MJO and BSISO over the Tropical Americas during the period 1980-2018. We also evaluate how the models of the S2S represent the diverse types of MJO and BSISO by using the Pearson correlation, the root mean square error, and the Brier skill score.The analysis shows that the four MJO types (slow, fast, stationary, and jumping) exhibit no convective signal over the Tropical Americas and the three BSISO types (canonical, north dipole, and east-expansion) have a strong signal on OLR, winds at 850 and 200 mb over the Tropical Americas. Considering the MJO types, the jumping and slow MJO reveal a small warm pool area, areas where the sea surface temperatures (SSTs) are higher than 28.5°C, over the Mexican Pacific, while the stationary and fast MJOs do not reach such high temperatures. Slow (fast) MJO has strong negative (positive) anomalies in SSTs over the central and Eastern Pacific Ocean. Considering the BSISO types, the canonical BSISO has the strongest westerly burst signal before the initiation of the BSISO events over the Maritime Continent, followed by easterly winds later. In contrast, the east-expansion BSISO shows weaker winds and negative OLR anomalies over Mexico. The northward dipole produces a small warm pool area over the Eastern Pacific Ocean when compared to the canonic and east expansion BSISO.We conclude that the MJO and BSISO types have different physical mechanisms for modulating the intraseasonal changes in the atmospheric and oceanic variables over the Tropical Americas. We also find that the ECMWF model has the best correlation skill when compared to other models from the S2S project.
Effects of solar wind density and velocity variations on the Martian ionosphere and plasma transport
Authors: Song Yihui , Lu Haoyu , Cao Jinbin , Wu Xiaoshu , Liu Yang , Li Shibang , Wang Siqi , Wild James A. , Zhou Chenling , Wang Jianxuan , Chen Nihan
Published: March 2024

Solar wind dynamic pressure, consisting solar wind density and velocity, is an important external driver that controls Martian plasma environment. In this study, a 3D magnetohydrodynamic model is applied to investigate the separate influences of solar wind density and velocity on the Martian ionosphere. The spatial distributions of ions in the dayside and near nightside ionosphere under different solar wind density and velocity conditions are analyzed, as well as the ion transport process. We find that for the same dynamic pressure condition, the ionosphere extends to higher altitudes under higher solar wind density, indicating that a solar wind velocity enhancement event is more efficient at compressing the Martian ionosphere. A higher solar wind velocity will result in a stronger induced magnetic field, shielding the Martian ionosphere, preventing the penetration of solar wind particles. For the same dynamic pressure, increasing solar wind density (decreasing velocity) leads to a higher horizontal ion velocity, facilitating day-to-night plasma transport. As a result, the ionosphere extends farther into the nightside. Also, the ion outflow flux is larger for high solar wind density, which may lead to a higher escape rate. Moreover, the strong crustal fields in the southern hemisphere also cause significant effect to the ionosphere, hindering horizontal ion transport. An additional outflow channel is also provided by the crustal field on the southern dayside, causing different responses of flow pattern between local and global scale while the solar wind condition is varied.
Examining Landscape Ecological Dynamics Amid Climate Change in the GBM Delta Region of the Indian Sundarbans
Authors: Mukhopadhyay Anirban , Pal Indrajit , Salehin Mashfiqus , Chowdhury Ahmed Ishtiaque Amin , Pramanick Nilay , Hati Jyoti Prakash , Ghosh Subhajit , Baskota Ayush , Chakraborty Subha , Sanyal Manas
Published: March 2024

The GBM delta stands as one of the world's most densely populated areas, where human activities have profoundly reshaped the landscape amid the challenges posed by recurring climatic disasters. The region, prone to tropical cyclones and flooding, faces a future where these natural hazards are expected to intensify, making the understanding of landscape ecological dynamics imperative for effective environmental management. This study scrutinizes the transformations in land use and land cover (LULC) dynamics within the GBM delta spanning three decades through integrating remote sensing and geographic information systems (GIS). Leveraging Landsat TM and OLI data, the research aims to discern anthropogenic alterations in land use patterns over the study period. Grey-level co-occurrence matrix (GLCM) analysis on Landsat datasets facilitates the identification of land use changes, employing the Support Vector Machine (SVM) as the classifying algorithm. In tandem, the study will document the influence of climatic disasters, assessing the impacts of tropical cyclones and floods in the delta. Rainfall and temperature anomalies will be calculated, while flooded areas will be delineated using Sentinel-1 Synthetic Aperture Radar (SAR) data. Climatic anomalies will be detected by analyzing TRMM, PERSIAN, and MODIS datasets. This research aims to unveil the intricate dynamics of the GBM delta's landscape over time by comprehensively understanding the interplay between anthropogenic activities and climatic events. The insights garnered, including the interests and livelihood operations of local communities, will be instrumental in informing government policies geared towards mitigating the escalating impacts of climatic disasters in the GBM delta.Key Words: Sundarbans, LULC, livelihood, GBM Delta, Policies.
Organising an international summer school from scratch, towards establishing the traditionally held one – HydRoData Summer School
Authors: Kuzmanić Tamara , Lebar Klaudija , Bezak Nejc , Vilfan Mojca , Šraj Mojca , Mikoš Matjaž
Published: March 2024

The first international summer school HydRoData for Master and PhD students was held in September 2023 at the University of Ljubljana, Faculty of Civil and Geodetic Engineering. The summer school was organised by the UNESCO Chair on Water-related Disaster Risk Reduction, University of Ljubljana, Slovenia and Slovenian national IHP programme. The focus of the summer school was data in hydrology. The programme topics included data acquisition, data manipulation and analysis, data curation, data communication, FAIR data principles, and introduction to R programming for hydrology.The teaching-learning process was structured as a combination of lectures, fieldwork, group work, ICT supported learning etc. In the scope of the summer school, participants partook the measurements of hydrological processes on several experimental plots, and visited meteorological station and radar during the field trip. To wrap everything up, the participants had the opportunity to show what they have learned in the competitive quiz in R programming.The official part of the summer school was enriched by social events, enabling the participants to network and get to know each other in more relaxed set-up. Social events included ice breaker trivia quiz pizza party, and a visit to traditional Slovenian tavern.The number of the applications exceeded the number of the available spots, and regardless on the new spots opening, a selection process was made. Finally, the 26 attending participants of 21 nationalities came from 19 universities. According to the feedback questionnaire, the participants evaluated the summer school execution with the average satisfaction grade 9.27 (out of 10). Here, the participant’s feedbacks that will assist in the improvement of the learning procedure, topic selection, schedule etc. will be presented more in detail along with the establishment and realization of the summer school.Since the first edition of the summer school showed to be successful, the second HydRoData summer school is announced, with applications already open. The HydRoData summer school 2024 will be held from 2 September to 6 September in Ljubljana, Slovenia. More information and registration form can be found: https://www.unesco-floods.eu/unesco-floods-summer-school/.