A document by Rosa Isabella Cuppari. Click on the document to view its contents.

The Jovian magnetodisk plays an essential role in the dynamics of the Jupiter system by coupling its various components. Here, we investigate the Juno (JADE, JEDI and MAG) observations of the magnetodisk within 20-80 Jupiter radii (RJ) in the 0-6 hour local time sector. JADE and JEDI data are combined to generate equatorial plane distributions of density, pressure, temperature, and anisotropy of electrons, protons, and heavy ions. Results show: (1) Heavy ions dominate both the number density and pressure. (2) The number density and pressure of all species decrease with radial distance. (3) The temperature increases for electrons and heavy ions and decreases for protons as radial distance increases. (4) On average, the parallel pressure exceeds the perpendicular pressure for all species. Based on these distributions, we explore the equilibrium and dynamics of the magnetodisk and show that: (1) Radial force balance is primarily achieved between the inward magnetic stress and the outward plasma anisotropy force. (2) An examination of the kappa parameters indicates that electrons, protons, and heavy ions primarily undergo adiabatic motion, magnetic moment diffusion, and stochastic motion, respectively. (3) A radial diffusion coefficient is derived from the radial profile of mass, providing an estimate of the timescale for radial transport from 20 to 80 RJ of  7 hours. (4) The total mass (\(5\times10^7\) kg) and thermal energy(\(3.8\times10^{37}\) eV) of the magnetodisk between 20 and 80 RJ are obtained.

Methane is the second most important anthropogenic greenhouse gas causing warming after carbon dioxide, and the emission reductions potentials are known to be limited due to the difficulty of abating agricultural methane. We explore in this study the emerging option of atmospheric methane removal (MR) that could complement carbon dioxide removal (CDR) in mitigation pathways. MR is technologically very challenging and potentially very expensive, so the main question is at which cost per ton of methane removed is MR more cost effective than CDR. To address this question, we use an intertemporal optimization climate-GHG-energy model to evaluate the MR cost and removal potential thresholds that would allow us to meet a given climate target with the same or a lower abatement cost and allowing for equal or higher gross CO2 emissions than if CDR through BECCS were an option. We also compare the effects of MR and CDR on the cost-effective mitigation pathways achieving four different climate targets. Using the ACC2-GET integrated carbon cycle, atmospheric chemistry, climate and energy system model, we consider a generic MR technology characterized by a given unit cost and a maximal removal potential. We show that to totally replace bioenergy based CDR with MR, the MR potential should reach at least 180 to 320 MtCH4 per year, i.e., between 50% and 90% of current anthropogenic methane emissions, with maximum unit cost between 10,000 and 34,000 $/tCH4, depending on the climate target. Finally, we found that replacing CDR by MR reshapes the intergenerational distribution of climate mitigation efforts by delaying further the mitigation burden.

Ozone is an important atmospheric constituent, exerting a pivotal influence on atmospheric chemistry, air quality, and climate change. The monitoring of its distribution and variation is crucial for advancing our   understanding of ozone development and related processes. This study presents the first spatial and temporal distributions of total ozone columns (TOC) retrieved from the Geostationary Interferometric Infrared Sounder (GIIRS), launched on board China’s FengYun-4B satellite (FY-4B/GIIRS) in 2021. Particularly, we focus on the variations of TOCs in East Asia from diurnal to seasonal time scales. Retrievals are implemented using spectra from March, June, September and December, representing different seasons. The results show that the degree of freedom for the signal (DOFS) typically exhibited a range of 0.8 to 1.4, with the vertical detection sensitivity of GIIRS peaking in the upper troposphere/lower stratosphere (UTLS) region, where the ozone variability is the highest. Collocation comparisons with the Infrared Atmospheric Sounding Interferometer (IASI) retrievals, the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA5) simulations and in situ ozone observations show good agreement. The comparisons of TOCs between GIIRS and ERA5 at different latitudes and different time scales demonstrate that FY-4B/GIIRS is effective in capturing the temporal and latitudinal variations of TOCs, particularly at middle and high latitudes. Our work demonstrates that FY-4B/GIIRS is of good capability to track ozone variations from diurnal to seasonal in East Asia, which will contribute to the understanding of the regional and global ozone variations.

A document by Rob Schmitz. Click on the document to view its contents.

This study introduces a machine learning approach to address the critical challenge of limited real-time flow data in river basins, particularly for calibrating large-scale hydrologic models. These models often rely on uncertain parameter transfers from gauged to ungauged regions, hindering accurate predictions. To mitigate this, we propose utilizing long short-term memory (LSTM) networks to estimate historic streamflow in ungauged watersheds, effectively creating “surrogate gauges.” Our innovative method treats watersheds as interconnected systems, leveraging downstream flow information to constrain and improve upstream flow estimates. By training and testing the LSTM on synthetic networks of conceptual ”leaky bucket” watershed models, we demonstrate its ability to outperform traditional methods. Notably, by representing watersheds as paired upstream-downstream networks, this concept can be generalized to any ungauged portion of a real basin, enhancing flow estimates in data-scarce scenarios. This research represents a proof of concept, highlighting the potential for significantly enhancing hydrologic modeling in data-scarce regions and providing a scalable method for watershed network analysis. Future work will focus on applying the model to real-world basins to validate its performance and scalability for continental-scale applications. Ultimately, this research aims to contribute to the development of more accurate and reliable hydrologic predictions.

Since the early 21st century, the Yellow River Source Basin (YRSB) has faced multiple flow disruptions, threatening water security for nearly one million downstream residents. Efforts such as the Ngoring Reservoir and Sanjiangyuan Ecological Reserve initially mitigated these issues. However, global climate change and the decommissioning of the Ngoring Reservoir have renewed these concerns. This study integrates multi-source satellite data (altimetry and imaging) and in-situ measurements (station and field) to simulate runoff in the YRSB from 2000 to 2020 and predict it with the IPCC data from 2021 to 2070 by long short-term memory (LSTM) model. Calculation results indicate that from 2000-2020, water storage in Lake Gyaring and Lake Ngoring increased by 0.47 billion m³ and 0.65 billion m³, respectively, with soil water rising by approximately 0.60 billion m³. About 40% of Lake Ngoring’s water comes from Lake Gyaring, crucial for mitigating extreme events if ecological integrity is maintained. Simulation runoff in high temperature is more sensitive to precipitation changes, while runoff in low temperature is more affected by evapotranspiration. Prediction results shows that under the most probable future, SSP 370 scenario, runoff recharge is expected to increase until mid-century but decline significantly thereafter due to rising evaporation, when the YRSB may be at risk of breakage.

The Arctic is warming rapidly, significantly reducing the Greenland ice sheet (GrIS) surface mass balance (SMB) and raising its contribution to global sea-level rise. Since these trends are expected to continue, it is essential to explore the GrIS SMB response to projected climate warming. We compare projections from three polar regional climate models, RACMO, MAR, and HIRHAM, forced by the Community Earth System Model CESM2 under a high-end warming scenario (SSP5-8.5, 1970-2099). We reveal different modeled SMB by 2100, including a twofold larger annual surface mass loss in MAR (-1735 Gt/yr) and HIRHAM (-1698 Gt/yr) relative to RACMO (-964 Gt/yr). Discrepancies primarily stem from differences in projected runoff, triggering melt-albedo positive feedback and subsequent modelled ablation zone expansion. In addition, we find different responses of modeled meltwater production to similar atmospheric warming. Our analysis suggests clear avenues for model developments to further improve SMB projections and contribution to sea-level rise.

This study investigates how the marine sediment proxies signal reflects dissolved oxygen levels in fjord basin water, to improve our understanding of the coastal marine deoxygenation that has been associated with the ongoing climate change. We use western Norwegian fjords to test how marine sediment proxies for dissolved oxygen perform. Such knowledge is needed to evaluate if recent reduced renewal of fjord basin waters is driven by anthropogenic impact or is within the range of natural variability. We have explored the potential and limitations of Mn/Ca, δ¹³C, benthic foraminiferal diversity, the calcareous and agglutinated foraminifera ratio, and the benthic foraminifera indicator species Stainforthia fusiformis, as potential proxies for bottom water oxygen concentrations. Among the fjords investigated in western Norway, seven stations are well-oxygenated, one is close to hypoxic oxygen levels, and one shows nearly anoxic conditions. The relative abundance of S. fusiformis shows the strongest potential as a tool for reconstructing past oxygen concentrations. The Mn/Ca and δ¹³C measured in the seawater also strongly correlate with dissolved oxygen. The foraminiferal diversity indices follow the oxygenation gradient in the fjords. The calcareous/agglutinated species ratio has limitations under anoxic conditions, where almost monospecific assemblage dominated by calcareous S. fusiformis was found. The signal of Mn/Ca and δ¹³C measured in shells of species Hyalinea balthica was difficult to assess due to low species abundance at some fjord sites. Hence, further analyses are necessary to employ the Mn/Ca and δ¹³C in foraminiferal shells as proxies for reconstructing past oxygen concentrations in fjords.

Atmospheric rivers (ARs) are filamentary structures within the atmosphere that account for a substantial portion of poleward moisture transport and play an important role in Earth’s hydroclimate. However, there is no one quantitative definition for what constitutes an atmospheric river, leading to uncertainty in quantifying how these systems respond to global change. This study seeks to better understand how different AR detection tools (ARDTs) respond to changes in climate states utilizing single-forcing climate model experiments under the aegis of the Atmospheric River Tracking Method Intercomparison Project (ARTMIP). We compare a simulation with an early Holocene orbital configuration and another with CO2 levels of the Last Glacial Maximum to a pre-industrial control simulation to test how the ARDTs respond to changes in seasonality and mean climate state, respectively. We find good agreement among the algorithms in the AR response to the changing orbital configuration, with a poleward shift in AR frequency that tracks seasonal poleward shifts in atmospheric water vapor and zonal winds. In the low CO2 simulation, the algorithms generally agree on the sign of AR changes but there is substantial spread in their magnitude, indicating that mean-state changes lead to larger uncertainty. This disagreement likely arises primarily from differences between algorithms in their thresholds for water vapor and its transport used for identifying ARs. These findings warrant caution in ARDT selection for paleoclimate and climate change studies in which there is a change to the mean climate state, as ARDT selection contributes substantial uncertainty in such cases.

Global climate models and reanalysis products have revealed large, persistent downwelling shortwave radiation biases over the Southern Ocean and coastal Antarctica. The biases are hypothesized to be caused by the incapability of models to accurately simulate the frequent occurrence of low-level mixed-phase clouds in these regions. In this study, we use the ground-based observations collected at Davis, Antarctica during the Precipitation over Land and The Southern Ocean (PLATO) field campaign in austral summer of 2019 to assess the capability of the high-resolution regional Unified Model (UM) to reproduce precipitating clouds off coastal Antarctica. We test the new UM double-moment Cloud AeroSol Interacting Microphysics (CASIM) scheme, running at the spatial resolution of 1.5-km and 100-m. We compare it to the previous single-moment cloud microphysics scheme at the same resolutions. The atmospheric configurations with double-moment cloud microphysics exhibit marginally degraded meteorological conditions relative to single-moment configurations compared with observations. For cloud properties, the UM regional models can generally simulate the phase, vertical structure and timing of events during the sublimation and precipitation periods. Nevertheless, overestimated ice water path and potentially underestimated liquid water path contribute to positive surface shortwave biases and negative longwave biases. The single moment microphysics simulates more liquid water path, though we suggest for the wrong reasons due to its ice nucleating parameterization. Our results suggest that the new double-moment cloud microphysics scheme, while having reduced performance in some respects, has large potential to better represent low-level mixed phase clouds for this region.

An advanced hodograph technique was applied to extract quasi-monochromatic, linear gravity wave (GW) packets from simultaneous wind and temperature measurements by a ground-based Doppler-Rayleigh-Mie-Raman lidar located in Kühlungsborn (54\,\textdegree N, 12\,\textdegree E). During the night of 11 to 12 February 2022, the stratospheric polar vortex was slightly elongated towards Central Europe. The polar night jet’s (PNJ) core was located nearly above the lidar. This unique meteorological situation allowed horizontal wind and temperature measurements in a stratospheric high-wind speed regime. GW refraction in the strong vertical gradient of the horizontal winds associated with the PNJ was observed. In addition, the subsequent low-pass filtering of upward and downward propagating GWs in the strong winds of the PNJ was demonstrated. A pair of upward and downward propagating GWs at the top and bottom edge of the PNJ’s core could be the result of shear excitation in the PNJ. A statistical analysis of intrinsic GW parameters is provided for all resolved linear GWs. Approximately 35\,\% of the resolved GWs propagate downward, and there is stronger filtering of the downward waves compared to the upward waves by the PNJ core. ECMWF-IFS horizontal winds and temperatures had a lower variability than the lidar and a poorer overall agreement above 50\,km. Stratospheric temperatures in ECMWF show a cool bias of greater than 2\,K.

Anthropogenic climate change has resulted in extreme rainfall and flooding on both a global and local scale. Flooding of urban areas can redistribute historical and present-day soil, sediment, and water contamination across affected areas and leave behind a sediment later laced with a suite of metals. This sediment layer poses a direct human health risk to the residents who live within these affected communities as well as the workers tasked with its cleanup. This study evaluated relative differences of total (Al, Fe, Co, Cr, Ni, Zn, Cu, As, Ba, Pb) and human bioaccessible (Zn, Cu, As, and Pb) metal concentrations in river flood sediment deposits in two urban communities in Philadelphia, P.A. (U.S.) (Manayunk and East Falls), which border the Schuylkill River, and have relative differences in historical industrial land use (Manayunk >>East Falls). Sediment deposits were collected immediately following a near record flooding event associated with the remnants of Hurricane Ida in September 2021. Statistically higher concentrations of Cr, Fe, Cu, Zn, As, and Pb in the Manayunk neighborhood suggests remobilization of contaminated soils as well as sediments from a historical industrial canal. Statistical analysis results also suggest the influence of roadway derived materials. Total metal and bioaccessible lead concentrations in excess of regulatory thresholds for residential soils suggests the sediments pose a substantial health risk to those who live and work in these areas. Collectively, the study results elucidate the public health risk associated with the deposition of flood sediment in urban areas.

The advent of under-ice profiling float and biologging techniques has enabled year-round observation of the Southern Ocean and its Antarctic margin. These under-ice data are often overlooked in widely used oceanographic datasets, despite their importance in understanding seasonality and its role in sea ice changes, water mass formation, and glacial melt. We develop a monthly climatology of the Southern Ocean (south of 40°S and above 2,000 m) using Data Interpolating Variational Analysis, which excels in multi-dimensional interpolation and consistent handling of topography and horizontal advection. The climatology successfully captures thermohaline variability under sea ice, previously hard to obtain, and outperforms other observation-based products and state estimate simulations in data fidelity, with smaller root-mean-square errors and biases. To demonstrate its multi-purpose capability, we present a qualitative description of the seasonal variation, including 1) the surface mixed layer, 2) the water mass volume census, 3) the Antarctic Slope Front, and 4) shelf bottom waters. Particularly, the circumpolar variation in the extent of dense shelf water and the annual volume overturning rate of water masses are revealed for the first time. The present work offers a new monthly climatology of the Southern Ocean and the Antarctic margin, which will be instrumental in investigating the seasonality and improving ocean models, thereby making valuable winter observations more accessible. We further highlight the quantitative significance of under-ice data in reproducing ocean conditions, advocating for their increased use to achieve a better Southern Ocean observing system.

Upwelling and decompression of mantle plumes is the primary mechanism for large volumes of intraplate volcanism; however, many seamounts do not correlate spatially, temporally, or geochemically with plumes. One region of enigmatic volcanism in the ocean basins that is not clearly attributable to plume-derived magmatism are the Geologist Seamounts and the wider South Hawaiian Seamount Province (∼19°N, 157°W). Here we present new bathymetric maps as well as 40Ar/39Ar age determinations and major and trace element geochemistry for six remote-operated vehicle recovered igneous rock samples (NOAA-OER EX1504L3) and two dredged samples (KK840824-02) from the Geologist Seamounts. The new ages indicate volcanism was active from 90–87 Ma and 74–73 Ma, inferring that, in conjunction with previous ages of ~84 Ma, seamount emplacement initiated near the paleo Pacific-Farallon spreading ridge and volcanism continued for at least ~17 m.y. Geochemical analyses indicate that Geologist Seamounts lava flows are highly alkalic and represent low-degree partial mantle melts primarily formed from a mixture of melting within the garnet and spinel stability field. The ages and morphology infer the seamounts were likely not related to an extinct plume. Instead, we build upon previous models that local microblock formation corresponded with regional lithospheric extension. We propose the microblock was bounded by the Molokai and short-lived Kana Keoki fracture zones. Regional deformation and corresponding volcanism among the Geologist Seamounts associated with the microblock potentially occurred in pulses contemporaneous to independently constrained changes in Pacific Plate motion —indicating that major changes in plate vectors can generate intraplate volcanism.

This study explores the relationship between dinoflagellate cyst (dinocyst) assemblages and the mixed layer depth (MLD) using canonical correspondence analyses. Our results demonstrate that wintertime deepening of MLD, in response to deep convection events, can influence dinocyst assemblages and especially the relative abundance of Nematosphaeropsis labyrinthus, which can thus be used as a proxy of MLD and the associated deep convection intensity. The analysis of Holocene N. labyrinthus percentage records in the subpolar North Atlantic, along with quantitative reconstructions of MLD from dinocyst assemblages, further reveals a westward migration of potential deep convection region around 6 ka BP, from the Nordic Seas and eastern subpolar gyre (SPG) during the Early Holocene, to the western to central SPG during the Middle and Late Holocene. The intensification of deep convection in the Labrador Sea towards a modern-like situation started during the Late Holocene, one or two thousand years later than the major transition around 6 ka BP in other parts of the subpolar North Atlantic. These results strengthen the hypothesis of reduced deep-water formation in the eastern North Atlantic from the early to late Holocene.

Mountain building reorganizes drainage networks, influencing riverine biodiversity. Northern Italy offers a natural experiment in the impact of tectonic and geomorphic processes on aquatic species distributions. We combined geomorphic analysis with environmental DNA from rivers to assess the influence of tectonically driven drainage reorganization on genetic diversity, targeting an endemic fish species, Telestes muticellus (A. Risso, 1827). In the Northern Apennines, horizontal shortening and topographic advection in an orogenic wedge have been hypothesized as leading to river capture and drainage divide migration. In addition, slab rollback has produced a spatial transition from contraction to extension, which is more pronounced from north to south, with normal faulting producing range-parallel drainage only in the southern regions. In contrast, the adjacent Ligurian Alps are a remnant of the Alpine orogen with little modern deformation. We found distinct zones of geomorphic characteristics from north to south, including divide asymmetry and frequency of range-parallel drainage. Analysis of DNA sequences shows cross-divide assemblage characteristics that correlate with the geomorphic zonation. The Northern Apennines show higher values of the directional measures of assemblage change gain, loss, and turnover; the Ligurian Alps show higher values of overlap and nestedness. There is a positive correlation between divide asymmetry and genetic distance, and gain, loss, and turnover of DNA sequences from Adriatic to Ligurian sites; there is a negative correlation with overlap and nestedness. Since the species is confined to freshwater environments, tectonically driven drainage reorganization is one of the only mechanisms that can explain its spatial genetic differentiation.

Accurately predicting Greenland’s ice mass loss is crucial to understanding future sea level rise. Approximately 50% of the mass loss results from iceberg calving at the ice-ocean interface. Ice mélange, a jammed, buoyant granular material that extends for 10 kilometers or more in Greenland’s largest fjords, can inhibit iceberg calving and discharge by transmitting shear stresses from fjord walls to glacier termini. Direct measurements of these resistive force dynamics are not possible in the field, thus, we created a scaled-down laboratory experiment to elucidate the most salient features of ice mélange mechanics. We captured videos of the mélange surface motion and sub-surface profile during slow, quasistatic flow through a rectangular fjord, and recorded the total force on a model glacier terminus. We find that when the wall friction is low, the ice mélange remains jammed, but moves as a solid plug with little or no particle rearrangements. When the wall friction is larger than the internal friction, shear zones develop near the walls, and the buttressing force magnitude and fluctuations increase significantly. Associated discrete particle simulations illustrate the internal flow in both regimes. We also compare our experimental results to a continuum, depth-averaged model of ice mélange and find that the thickness of the mélange at the terminus provides a good indicator of the net buttressing force. However, the continuum model cannot capture the stochastic nature of the rearrangements and concomitant fluctuations in the buttressing force. These fluctuations may be important for short-time and seasonal controls on iceberg calving rates.