bluuebunny/crossref_metadata_2025_split huggingface dataset:
Martian Atmospheric Aerosols Composition and Distribution Retrievals During the First Martian Year of NOMAD/TGO Solar Occultation Measurements: 1. Methodology and Application to the MY 34 Global Dust Storm
Authors: Stolzenbach Aurélien , López Valverde Miguel‐Angel , Brines Adrian , Modak Ashimananda , Funke Bernd , González‐Galindo Francisco , Thomas Ian , Liuzzi Giuliano , Villanueva Gerónimo , Luginin Mikhail , Aoki Shohei , Grabowski Udo , Lopez Moreno José Juan , Rodrìguez Gòmez Julio , Wolff Mike , Ristic Bojan , Daerden Frank , Bellucci Giancarlo , Patel Manish , Vandaele Ann‐Carine 
Published: November 2023

AbstractSince the beginning of the Trace Gas Orbiter (TGO) science operations in April 2018, its instrument “Nadir and Occultation for MArs Discovery” (NOMAD) supplies detailed observations of the IR spectrums of the Martian atmosphere. We developed a procedure that allows us to evaluate the composition and distribution's parameters of the atmospheric Martian aerosols. We use a retrieval program (RCP) in conjunction with a radiative forward model (KOPRA) to evaluate the vertical profile of aerosol extinction from NOMAD measurements. We then apply a model/data fitting strategy of the aerosol extinction. In this first article, we describe the method used to evaluate the parameters representing the Martian aerosol composition and size distribution. MY 34 GDS showed a peak intensity from LS 190° to 210°. During this period, the aerosol content rises multiple scale height, reaching altitudes up to 100 km. The lowermost altitude of aerosol's detection during NOMAD observation rises up to 30 km. Dust aerosols reff were observed to be close to 1 μm and its νeff lower than 0.2. Water ice aerosols reff were observed to be submicron with a νeff lower than 0.2. The vertical aerosol structure can be divided in two parts. The lower layers are represented by higher reff than the upper layers. The change between the lower and upper layers is very steep, taking only few kilometers. The decaying phase of the GDS, LS 210°–260°, shows a decrease in altitude of the aerosol content but no meaningful difference in the observed aerosol's size distribution parameters.
Filling the Gap of Wind Observations Inside Tropical Cyclones
Authors: Tridon F. , Battaglia A. , Rizik A. , Scarsi F. E. , Illingworth A. 
Published: November 2023

AbstractThe WIVERN (WInd VElocity Radar Nephoscope) mission, currently under the Phase‐0 of the ESA Earth Explorer program, promises to provide new insight in the coupling between winds and microphysics by globally observing, for the first time, vertical profiles of horizontal winds in cloudy areas. The objective of this work is to explore the potential of the WIVERN conically scanning Doppler 94 GHz radar for filling the wind observation gap inside tropical cyclones (TCs). To this aim, realistic WIVERN notional observations of TCs are produced by combining the CloudSat 94 GHz radar reflectivity observations from 2007 to 2009 with ECMWF co‐located winds. Despite the short wavelength of the radar (3 mm), which causes strong attenuation in presence of large amount of liquid hydrometeors, the system can profile most of the TCs, particularly the cloudy areas above the freezing level and the precipitating stratiform regions. The statistical analysis of the results shows that, (a) because of its lower sensitivity, a nadir pointing WIVERN would detect 75% of the clouds observed by CloudSat (45% of winds with 3 m s−1 accuracy, in comparison to CloudSat sampling of clouds), (b) but thanks to its scanning capability, WIVERN would actually provide 53 times more observations of clouds than CloudSat in TCs (30 times more observations of horizontal winds), (c) this corresponds to about 350 (200) million observations of clouds (accurate winds) every year. Such observations could be used to shed light on the physical processes underpinning the evolution of TCs and in data assimilation in order to improve numerical weather prediction.
The Emerging Golden Age of Satellite Altimetry to Prepare Humanity for Rising Seas
Authors: Hamlington B. D. , Willis J. K. , Vinogradova N. 
Published: November 2023

AbstractWith the success of the Sentinel‐6 Michael Freilich satellite, the satellite radar altimetry record of sea level has now surpassed 30 years in length. This reference satellite mission has continued uninterrupted alongside a significant expansion of the satellite sea‐level observing network in the past decade. This expansion was punctuated by the launch of the Surface Water and Ocean Topography mission in December 2022, which will bring higher resolution measurements of sea level closer to the shore than ever before. Here, we take stock of where we are now in terms of using satellites to measure sea level, and what is still needed to address the growing need of those living along the coast for information to support planning and adaptation efforts.
A Country Wide Evaluation of Sweden's Spatial Flood Modeling With Optimized Convolutional Neural Network Algorithms
Authors: Panahi Mahdi , Khosravi Khabat , Rezaie Fatemeh , Ferreira Carla S. S. , Destouni Georgia , Kalantari Zahra 
Published: November 2023

AbstractFlooding is one of the most serious and frequent natural hazards affecting human life, property, and the environment. This study develops and tests a deep learning approach for large‐scale spatial flood modeling, using Convolutional Neural Network (CNN) and optimized versions combined with the Gray Wolf Optimizer (GWO) or the Imperialist Competitive Algorithm (ICA). With Sweden as an application case for nation‐wide flood susceptibility mapping, this modeling approach considers ten geo‐environmental input factors (slope, elevation, aspect, plan curvature, length of slope, topographic wetness index, distance from river, distance from wetland, rainfall, and land use). The GWO and ICA optimization improves model prediction by 12% and 8%, respectively, compared with the standalone CNN model performance. The results show 40% of the land area, 45% of the railroad, and 43% of the road network of Sweden to have high or very high flood susceptibility. They also show the aspect to have the highest input factor impact on flood susceptibility prediction while, for example, rainfall ranks only seven of the total 10 considered geo‐environmental input factors. In general, accurate nation‐wide flood susceptibility prediction is essential for guiding flood management and mitigation efforts. This study's approach to such prediction has emerged as well‐performing and cost‐effective for the case of Sweden, calling for further application and testing in other world regions.
Aerosol Shortwave Radiative Heating and Cooling by the 2017 and 2023 Chilean Wildfire Smoke Plumes
Authors: de Graaf Martin , Tilstra L. Gijsbert , Stammes Piet 
Published: November 2023

AbstractThe aerosol shortwave, direct radiative effects of smoke plumes from Chilean wildfires in 2017 and 2023 were derived from satellite observations in both cloud‐free and cloud scenes. At the top of the atmosphere, the aerosol DRE changes sign when aerosol overly clouds or open ocean, confirmed by both measurements and a simulation study. The cloud‐free daily‐mean DRE, computed using an offline radiative transfer model (RTM), was 66 W m−2 in 2023 and 42 W m−2 in 2017, due to absorption by smoke. However, the total radiative effects were larger in 2017 due to a larger plume size compared to 2023. The method presented here provides a new conceptual model to quickly assess the radiative effects of wildfire smoke plumes using satellite measurements and pre‐computed RTM results. The presented estimates are strongly affected by the uncertainty of aerosol optical thickness retrievals from satellite, which can be large in the presence of clouds.
Using Tidally‐Driven Elastic Strains to Infer Regional Variations in Crustal Thickness at Enceladus
Authors: Berne Alexander , Simons Mark , Keane James T. , Park Ryan S. 
Published: November 2023

AbstractConstraining the spatial variability of the thickness of the ice shell of Enceladus (i.e., the crust) is central to our understanding of the internal dynamics and evolution of this small Saturnian moon. In this study, we develop a new methodology to infer regional variations in crustal thickness using measurements of tidally‐driven elastic strain that could be made in the future. As proof of concept, we recover thickness variations from synthetic finite‐element crustal models subjected to diurnal eccentricity tides. We demonstrate recovery of crustal thickness to within ∼2 km of true values across the crust with ∼10% error in derived spherical harmonic coefficients at degrees l ≤ 12. Our computed uncertainty is significantly smaller than the inherent ∼10 km ambiguity associated with crustal thickness derived solely from gravity and topography measurements. Therefore, future measurements of elastic strain can provide a robust approach to probe crustal structure at Enceladus.
The Contribution of Plasma Sheet Bubbles to Stormtime Ring Current Buildup and Evolution of Its Energy Composition
Authors: Sciola A. , Merkin V. G. , Sorathia K. , Gkioulidou M. , Bao S. , Toffoletto F. , Pham K. , Lin D. , Michael A. , Wiltberger M. , Ukhorskiy A. 
Published: November 2023

AbstractThe formation of the stormtime ring current is a result of the inward transport and energization of plasma sheet ions. Previous studies have demonstrated that a significant fraction of the total inward plasma sheet transport takes place in the form of bursty bulk flows, known theoretically as flux tube entropy‐depleted “bubbles.” However, it remains an open question to what extent bubbles contribute to the buildup of the stormtime ring current. Using the Multiscale Atmosphere Geospace Environment Model, we present a case study of the 17 March 2013 storm, including a quantitative analysis of the contribution of plasma transported by bubbles to the ring current. We show that bubbles are responsible for at least 50% of the plasma energy enhancement within 6 RE during this strong geomagnetic storm. The bubbles that penetrate within 6 RE transport energy primarily in the form of enthalpy flux, followed by Poynting flux and relatively little as bulk kinetic flux. Return flows can transport outwards a significant fraction of the plasma energy being transported by inward flows, and therefore must be considered when quantifying the net contribution of bubbles to the energy buildup. Data‐model comparison with proton intensities observed by the Van Allen Probes show that the model accurately reproduces both the bulk and spectral properties of the stormtime ring current. The evolution of the ring current energy spectra throughout the modeled storm is driven by both inward transport of an evolving plasma sheet population and by charge exchange with Earth's geocorona.
Large Scale Traveling Ionospheric Disturbances During Geomagnetic Storms of 17 March and 23 June 2015 in the Australian Region
Authors: Kishore Amol , Kumar Sushil 
Published: November 2023

AbstractLarge scale traveling ionospheric disturbances (LSTIDs) can be detected using the critical frequency of F2 layer (foF2) of the ionosphere. The HF interferometry (HF‐int) technique is applied to the ionosonde data from low and mid latitude stations over Australia. For the first time, we present a comparison of TIDs detected during the geomagnetic storms of 17 March and 23 June 2015. The TID response for these two comparable superstorms is significantly different owing to the differing storm evolution patterns. The storm associated TIDs are more intense and longer compared to the solar terminator. Results demonstrate that the morphology of parameters continually varies over time due to highly dynamic ionospheric response to geomagnetic storms. For the March storms, TIDs velocities were 400–700 m/s at the onset phase, ∼500 m/s during the main phase and ∼600 m/s during the recovery phase. Their propagation directions were equatorward with east/west deviations. Lower period (∼60 min) TIDs were determined during storm onset whereas higher periods (∼140 min) were detected during the recovery phase. The June storm produced a different response. The TID velocity at the onset phase was ∼500 m/s but during the main and recovery phases the velocities were greater than 1,000 m/s. There were large deviations in velocity vectors at the different stations suggesting multiple sources of TID generation and possible resonating effects at middle and low latitude stations. Our findings indicate that while TID detection and storm phases co‐occur, the propagation characteristics of TIDs change dramatically throughout the storm.
Do Subducted Seamounts Act as Weak Asperities?
Authors: Lee Sungho , Choi Eunseo , Scholz Christopher H. 
Published: November 2023

AbstractThe additional work of ploughing makes seamounts more resistant to subduction and more strongly coupled than smoother areas. Nevertheless, the idea that subducted seamounts are weakly coupled and slip aseismically has become dominant in the last decade. This idea is primarily based on the claim that a seamount being subducted in the southern Japan Trench behaves this way. The key element in this assertion is that large M ∼ 7 earthquakes that abut the leading edge of the seamount require that the seamount be aseismically sliding to initiate them. More recent observations show instead that the surrounding region is aseismically sliding while the seamount acts as a stationary buttress. Here we re‐examine this case and model it with both weak and strong asperity assumptions. Our modeling results show that only a strong asperity model can produce this type of earthquake. Strong asperities also rupture the seamount in great earthquakes with long recurrence times. This provides the previously unknown source for a series of great tsunami earthquakes that have occurred along the southern Japan Trench, the most recent being the 1677 M8.3–8.6 Enpo Boso‐oki tsunami earthquake. The “weak asperity” hypothesis is thus found to be false in this foundational example.
The Effects of Aerosol on Small‐Scale Cloud‐Environment Mixing: Implications for Simulating and Observing Inhomogeneous Mixing
Authors: Kainz Johannes , Hoffmann Fabian 
Published: November 2023

AbstractEntrainment‐mixing modulates the number and size of cloud droplets, and thus affects the optical properties of clouds and their role in the climate system. Using a statistical turbulence model coupled with Lagrangian cloud microphysics, we analyze the role of aerosol in the entrainment‐mixing process, which, for instance, prevent the full evaporation of cloud droplets, leaving behind haze particles. To test a commonly applied indicator for inhomogeneous mixing, a set of different mixing scenarios is simulated. We conclude that if a hard separation radius between cloud droplets and haze particles is chosen, the typical classification into homogeneous and inhomogeneous mixing can be wrong because larger haze particles might be misidentified as cloud droplets, making the mixing appear more homogeneous. Furthermore, we show that the growth of cloud droplets on the expense of other hydrometeors due to differences in aerosol loading and particle curvature (Ostwald ripening) can produce cloud microphysical signatures indistinguishable from inhomogeneous mixing. Finally, we investigate how the consideration of haze particles can mitigate the previously reported negative impacts of inhomogeneous mixing on the cloud albedo. These findings should be considered when interpreting observations and simulations of small‐scale entrainment‐mixing.
Martian Atmospheric Aerosols Composition and Distribution Retrievals During the First Martian Year of NOMAD/TGO Solar Occultation Measurements: 2. Extended Results, End of MY 34 and First Half of MY 35
Authors: Stolzenbach Aurélien , López Valverde Miguel‐Angel , Brines Adrian , Modak Ashimananda , Funke Bernd , González‐Galindo Francisco , Thomas Ian , Liuzzi Giuliano , Villanueva Gerónimo , Luginin Mikhail , Aoki Shohei , Grabowski Udo , Lopez Moreno José Juan , Rodriguez‐Gomez Julio , Wolff Mike , Ristic Bojan , Daerden Frank , Bellucci Giancarlo , Patel Manish , Vandaele Ann‐Carine 
Published: November 2023

AbstractThis is the second part of Stolzenbach et al. (2023, https://doi.org/10.1029/2022JE007276), named hereafter Paper I, extends the period to the end of MY 34 and the first half of MY 35. This encompasses the end phase of the MY 34 Global Dust Storm (GDS), the MY 34 C‐Storm, the Aphelion Cloud Belt (ACB) season of MY 35, and an unusual early dust event of MY 35 from LS 30° to LS 55°. The end of MY 34 overall aerosol size distribution shows the same parameters for dust and water ice to what was seen during the MY 34 GDS. Interestingly, the layered water ice vertical structure of MY 34 GDS disappears. The MY 34 C‐Storm maintains condition like the MY 34 GDS. A high latitude layer of bigger water ice particles, close to 1 μm, is seen from 50 to 60 km. This layered structure is linked to an enhanced meridional transport characteristic of high intensity dust event which put the MY 34 C‐Storm as particularly intense compared to non‐GDS years C‐Storms as previously suggested by Holmes et al. (2021, https://doi.org/10.1016/j.epsl.2021.117109). Surprisingly, MY 35 began with an unusually large dust event (Kass et al., 2020, https://ui.adsabs.harvard.edu/abs/2020AGUFMP039…01K) found in the Northern hemisphere during LS 35° to LS 50°. During this dust event, the altitude of aerosol first detection is roughly equal to 20 km. This is close to the values encountered during the MY 34 GDS, its decay phase and the C‐Storm of the same year. Nonetheless, no vertical layered structure was observed.
Using Normalize Difference Vegetation Index to Infer Wetlands Salinity and Organic Contribution to Vertical Accretion Rates
Authors: Cortese L. , Jensen D. J. , Simard M. , Fagherazzi S. 
Published: November 2023

AbstractVegetation is a key component controlling soil accretion in coastal wetlands through production of belowground organic matter and enhanced deposition of mineral sediments. Vegetation structure is a proxy for wetland health and degradation that can be monitored at large scales with remote sensing. Among different multispectral indices, the Normalized Difference Vegetation Index (NDVI) is generally used for this purpose. Using Google Earth Engine (GEE), NDVI time‐series are extracted around 45 monitoring stations of the Coastwide Reference Monitoring System (CRMS) located in Terrebonne Bay, Louisiana, USA. NDVI tends to increase from saline to freshwater wetlands. Using these NDVI observations and in situ measurements of salinity, soil accretion rates, and geomorphic metrics (i.e., elevation, distance from the bay or from the nearest channel bank), empirical models were developed to derive maps of organic mass accumulation rates and salinity. The analysis shows that NDVI can be used to reproduce the salinity gradient in Terrebonne Bay, as the index captures differences in vegetation cover, which depend on salinity. A negative relationship between NDVI and organic accumulation mass rates is also found, indicating that saline marshes tend to accumulate more organic material compared to fresh wetlands.
The Effect of Sediment Supply on Pool‐Riffle Morphology
Authors: Lei Yunlong , Hassan Marwan A. , Viparelli Enrica , Chartrand Shawn M. , An Chenge , Fu Xudong , Hu Chunhong 
Published: November 2023

AbstractDownstream width variations can generate pool‐riffle morphology under experimental conditions, in numerical simulations and natural river channels. The present understanding of how pool‐riffle morphology varies with sediment supply and caliber, however, is insufficient due to the limited range of sediment supply rates explored in previous experiments and the little attention paid to sand supply and sediment size distribution in the laboratory and in the field. We present a model of river morphodynamics that can account for the spatial variability of channel width, and we validate the model with experimental data. Model validation shows how this one‐dimensional model can capture pool‐riffle formation, growth, and equilibration with errors that are comparable with those of other 1D models of river morphodynamics. We then apply the validated model to study the effects of sediment supply rate and caliber on pool‐riffle morphology. Model results show that pool‐riffle morphology is resilient to the range of tested sediment supply (i.e., five‐fold the sediment amount, 41‐fold the sand amount and coarsening the gravel supply). Bed and water surface slopes are sensitive to all types of change of sediment supply, whereas the sensitivity of bed surface sediment grain size varies with the type of change. These findings support prior research emphasizing the role of downstream width variations for the development/maintenance of pool‐riffle morphology and can help in the restoration and recovery of pool‐riffle gravel‐bed rivers.
Unraveling population trends in Italy (1921–2021) with spatial econometrics
Authors: Alaimo Leonardo Salvatore , Ciaschini Clio , Mariani Francesca , Cudlinova Eva , Postigliola Michele , Strangio Donatella , Salvati Luca 
Published: November 2023

AbstractTesting density-dependence and path-dependence in long-term population dynamics under differentiated local contexts contributes to delineate the changing role of socioeconomic forces at the base of regional disparities. Despite a millenary settlement history, such issue has been rarely investigated in Europe, and especially in highly divided countries such as those in the Mediterranean region. Using econometric modeling to manage spatial heterogeneity, our study verifies the role of selected drivers of population growth at ten times between 1921 and 2021 in more than 8000 Italian municipalities verifying density-dependent and path-dependent dynamics. Results of global and quantile (spatial) regressions highlight a differential impact of density and (lagged) population growth on demographic dynamics along the urban cycle in Italy. Being weakly significant in the inter-war period (1921–1951), econometric models totalized a high goodness-of-fit in correspondence with compact urbanization (1951–1981). Model’s fit declined in the following decades (1981–2021) reflecting suburbanization and counter-urbanization. Density-dependence and path-dependence were found significant and, respectively, positive or negative, with compact urbanization, and much less intense with suburbanization and counter-urbanization. A spatial econometric investigation of density-dependent and path-dependent mechanisms of population dynamics provided an original explanation of metropolitan cycles, delineating the evolution of socioeconomic (local) systems along the urban-rural gradient.