• Issue
    Volume 50, Issue 14
    28 July 2023

Issue Information

Free Access

Issue Information

  • First Published: 10 July 2023

Research Letter

Solid Earth

Open Access

Separating Hydraulic Fracturing Microseismicity From Induced Seismicity by Bayesian Inference of Non-Linear Pressure Diffusivity

  • First Published: 26 July 2023
Key Points

  • Diffusivity can separate microseismicity created by hydraulic fracturing from induced seismicity to permit structural analysis

  • Bayesian quantile regression robustly estimates the linear and non-linear diffusivity parameters required for this segregation

  • We reveal a direct connection between hydraulic fracturing and faults associated with induced seismicity

Oceans

Open Access

Decadal Reorganization of Subantarctic Mode Water

  • First Published: 11 July 2023
Key Points

  • Decadal fluctuations of Subantarctic Mode Water volume regionally exceed long-term trends and exhibit compensating volume changes of lighter and denser water

  • This two-layer density reorganization is imposed by surface heat (Indian, central Pacific) and freshwater (southeast Pacific) fluxes

  • The reorganization is significantly impacted by the Interdecadal Pacific Oscillation, inducing a variability dipole in each basin

Climate

Open Access

The Relationships Between Meridional Position of North Pacific Sea Surface Temperature Anomalies and North American Surface Temperatures Revealed by CMIP6 Models

  • First Published: 24 July 2023
Key Points

  • North American warming anomaly occurs during North Pacific sea surface temperature anomaly events located north

  • The warming anomaly is related to an enhanced Aleutian low anomaly located north and climatological westerly

  • During the events located south, North American surface temperature responses are weak due to a southward-shift Aleutian low anomaly

Oceans

Open Access

Vertical Momentum Transport by Internal Gravity Waves Above the Equatorial Undercurrent at 140°W

  • First Published: 23 July 2023
Key Points

  • Energetic internal waves are found in the highly sheared region above the Equatorial Undercurrent in the Eastern Equatorial Pacific

  • The waves support a large momentum exchange between the westward flowing S. Equatorial Current and the eastward moving Undercurrent below

  • The waves are triggered by nocturnal convection, fueled by wind driven shear, and maintained by over-reflection at a near-surface critical layer

Atmospheric Science

Open Access

Tropical Pacific Influence on Summertime South African High-Frequency Temperature Variability and Heat Waves

  • First Published: 21 July 2023
Key Points

  • El Niño accompanies enhanced summertime high-frequency temperature variability over South Africa

  • Due to enhanced baroclinic energy conversion concomitant with a northward shift of the jetstream and baroclinic zone toward South Africa

  • The enhanced high-frequency variance coincides with warmer seasonal-mean temperatures, leading to more frequent warm extremes

Open Access

Inter-Annual Variability in Atmospheric Transport Complicates Estimation of US Methane Emissions Trends

  • First Published: 13 July 2023
Key Points

  • Atmospheric transport explains an upward trend in observed atmospheric methane enhancements across the US between years 2008 and 2015

  • The time modeled air masses spend over North America varies by 15%–20% among years and correlates with variability in methane enhancements

  • Modeled methane enhancements at satellite and in situ monitoring sites are 19% higher during El Niño than La Niña

Open Access

Resonant Waves Play an Important Role in the Increasing Heat Waves in Northern Hemisphere Mid-Latitudes Under Global Warming

  • First Published: 17 July 2023
Key Points

  • The influence of resonant waves on heat extremes in the Northern Hemisphere mid-latitude summer is increasing, especially in Eurasi

  • The occurrence of resonant waves is closely related to double jets, accompanied by the enhancement of atmospheric blocking

  • The occurrence of resonant waves is accompanied by the weakening of the upward-propagating planetary waves

Climate

Open Access

Extreme Precipitation-Temperature Scaling in California: The Role of Atmospheric Rivers

  • First Published: 25 July 2023
Key Points

  • Precipitation-temperature (P-T) scaling rates during atmospheric rivers (ARs) are larger than other precipitation events in California

  • P-T scaling rates for AR-based events approach the Clausius-Clapeyron rate (7% per °C) when using dew point temperature

  • The differences in P-T scaling rates for ARs versus non-ARs are linked to the sensitivity of moisture content and lifting mechanism to warming

Space Sciences

Open Access

New Perspective on Phase Space Density Analysis for Outer Radiation Belt Enhancements: The Influence of MeV Electron Injections

  • First Published: 18 July 2023
Key Points

  • Rapid and intermittent electron enhancement pattern significantly impacts phase space density (PSD) analysis

  • Inbound spacecraft can observe a temporal PSD peak during rapid electron enhancements driven by injections

  • Quasi-stationary time intervals between enhancements enable accurate determination of PSD radial profiles

Open Access

Substorm Impact on Dayside Ionospheric Currents

  • First Published: 13 July 2023
Key Points

  • Analyses of ground magnetometer data from substorms during northward Interplanetary Magnetic Field (IMF) show that substorms impact the NBZ dayside ionospheric currents

  • During substorms under northward IMF conditions, lobe cells are unusually weak before onset and become more distinct after

  • We suggest possible mechanisms by which magnetotail dynamics can influence dayside ionospheric currents

Hydrology and Land Surface Studies

Open Access

Pre-Vegetation, Single-Thread Rivers Sustained by Cohesive, Fine-Grained Bank Sediments: Mesoproterozoic Stoer Group, NW Scotland

  • First Published: 20 July 2023
Key Points

  • Quantitative paleohydraulic tools indicate that deep, low-sloping rivers were characteristic of 1.2 Ga Stoer Group

  • Paleohydraulic data plot in the single-thread river planform regime in mechanistic frameworks for discriminating channel planform

  • Field observations and theory indicate that the mud in bank sediments can provide sufficient cohesion to maintain deep flows

Atmospheric Science

Open Access

Deep Learning Improves GFS Wintertime Precipitation Forecast Over Southeastern China

  • First Published: 26 July 2023
Key Points

  • A deep learning model based on data augmentation (DA) is proposed to improve the Global Forecast System wintertime precipitation forecast

  • The deep learning model improves the heavy precipitation forecast at lead times within 48 hr

  • DA plays a critical role in the heavy precipitation forecast

Open Access

Quantifying the Efficiency of Stratospheric Aerosol Geoengineering at Different Altitudes

  • First Published: 20 July 2023
Key Points

  • We compare two stratospheric aerosol injection strategies which inject SO2 at different altitudes to meet the same temperature target

  • The low altitude strategy requires two thirds more injection to provide the same amount of cooling

  • We isolate and quantify the different factors which cause the high altitude injection strategy to cool the surface more efficiently

Solid Earth

Open Access

Enhanced Tidal Sensitivity of Seismicity Before the 2019 Magnitude 7.1 Ridgecrest, California Earthquake

  • First Published: 20 July 2023
Key Points

  • Seismicity in the Ridgecrest area is modulated by the solid Earth tides

  • Peak seismicity occurs when tidal Coulomb stress or stress rate favors rupture

  • Strength of tidal triggering is gradually increasing in the rupture area about 2 years before the Mw 7.1 2019 mainshock

Space Sciences

Open Access

IMF Dependence of Midnight Bifurcation in the Thermospheric Wind at an Auroral Latitude Based on Nine Winter Measurements in Tromsø, Norway

  • First Published: 24 July 2023
Key Points

  • The thermospheric wind from a Fabry-Perot interferometer (630 nm) and the ionospheric plasma velocity from a Dynasonde were compared

  • The zonal wind bifurcates immediately before midnight for interplanetary magnetic field By < 0, but for By > 0, it inverts gradually into the postmidnight sector

  • The wind bifurcation signature is different from the ion velocity bifurcation, probably due to advection from the polar cap region

Atmospheric Science

Open Access

Horizontal Wavenumber Spectra Across the Middle Atmosphere From Airborne Lidar Observations During the 2019 Southern Hemispheric SSW

  • First Published: 20 July 2023
Key Points

  • Horizontal wavenumber spectra across the middle atmosphere are computed using airborne lidar observations during the 2019 sudden stratospheric warming (SSW)

  • Horizontal wavenumber spectra are close to k−5/3 in the stratosphere, and become shallower in the mesosphere during the SSW

  • Observational evidence is provided that the mesoscale spectral slope in the middle atmosphere is caused by the occurrence of gravity waves

Oceans

Open Access

Effects of the Hunga Tonga-Hunga Ha'apai Eruption on MODIS-Retrieved Sea Surface Temperatures

  • First Published: 17 July 2023
Key Points

  • Stratospheric sulfate aerosols in Tonga eruption plume affect sea-surface temperature from Moderate Resolution Imaging Spectroradiometer

  • Negative biases of sea-surface temperature were pronounced in Southern Hemispheric tropics initially and spread to mid-latitude after May

  • A negative offset of 11–12 μm brightness temperature difference is due to more absorption by aerosol at 11 μm, opposite to H2O absorption

Cryosphere

Open Access

DNN-Based Retrieval of Arctic Sea Ice Concentration From GNSS-R and Its Effects on the Synoptic-Scale Forecasting as Supplementary Observation Source

  • First Published: 18 July 2023
Key Points

  • An innovative method for retrieving sea ice concentration (SIC) at Global Navigation Satellite Systems Reflectometry (GNSS-R) subsatellite points is presented, considering the marine factors

  • The joint assimilation of retrieved GNSS-R SIC and passive microwave remote sensing SIC is a useful means to improve the forecast accuracy

  • More GNSS-R SIC data in areas with large SIC gradient will bring more useful information to the sea ice forecast

Hydrology and Land Surface Studies

Open Access

Inferring Hillslope Groundwater Recharge Ratios From the Storage-Discharge Relation

  • First Published: 25 July 2023
Key Points

  • Increases in hillslope groundwater storage can be quantified from storage-discharge relations

  • Field measurements of groundwater and vadose zone (VZ) storage corroborate seasonality in recharge ratios (recharge per precipitation input)

  • Recharge ratio increases with decreasing plant-driven VZ (soil and rock) storage deficits, reflecting spatial variations in storage

Climate

Open Access

Seventy-Year Trends in Ship-Reported Oceanic Precipitation Frequency

  • First Published: 20 July 2023
Key Points

  • Significant long-term trends are found in ship reports of precipitation occurrence

  • Trends are mostly positive equatorward of 45° and negative at higher latitudes

  • Reporting biases that could explain the trends cannot be ruled out but have not been identified

Hydrology and Land Surface Studies

Open Access

Multiple Seepage-Faces in Tidal Flat With Very Gentle Slopes

  • First Published: 20 July 2023
Key Points

  • Tidal groundwater flow with strict and explicit seepage-face boundary conditions were numerically simulated

  • Multiple seepage-faces were first found to develop on gentle tidal flat with slope around 1‰

  • Multiple seepage-faces imply multiple local density-dependent groundwater-seawater re-circulations

Open Access

The Role of Anomalous Transport in Long-Term, Stream Water Chemistry Variability

  • First Published: 17 July 2023
Key Points

  • An hydrological catchment system at kilometer scales is shown to exhibit anomalous (non-Fickian) transport over a 36-year period

  • A continuous time random walk suggests two distinct power-law regimes in the distribution of overall catchment travel times

  • In the catchments considered here, preferential flow appears to occur at all length and time scales

Atmospheric Science

Open Access

Response of Tropical Overshooting Deep Convection to Global Warming Based on Global Cloud-Resolving Model Simulations

  • First Published: 26 July 2023
Key Points

  • The Nonhydrostatic Icosahedral Atmosphere Model well reproduces observed spatiotemporal distributions of tropical overshooting deep convections (ODCs)

  • Tropical ODC increases with global temperature on ocean (land) by 7%/K (−1%/K) for ODCs above 15.5 km, 27%/K (10%/K) above 16.9 km, and 90%/K (37%/K) above 18.4 km

  • Response of tropical ODCs that penetrate the tropical cold point tropopause height to global warming is 3%/K, with 6%/K over the ocean and −3%/K on land

Hydrology and Land Surface Studies

Open Access

Barchan Dunes Cruising Dune-Size Obstacles

  • First Published: 10 July 2023
Key Points

  • We show that subaqueous barchans can be blocked, bypass, or pass over dune-size obstacles

  • In some cases, barchans can split in two or more bedforms

  • We propose that the barchan behavior depends basically on two dimensionless parameters

Open Access

Estimation of the Snow Water Equivalent Using Muon Scattering Radiography

  • First Published: 23 July 2023
Key Points

  • We test the suitability of Muon Scattering Radiography to infer the Snow Water Equivalent (SWE)

  • Numerical simulations show the technique can estimate the SWE with a precision of around 12 mm

  • Laboratory measurements confirm the results obtained with simulation

Climate

Open Access

Robust Relationship Between Midlatitudes CAPE and Moist Static Energy Surplus in Present and Future Simulations

  • First Published: 13 July 2023
Key Points

  • Convective available potential energy (CAPE) shows a strong dependence on “moist static energy surplus” and this dependence holds across climate states. These results are robust across models

  • Shifts in CAPE contours under climate change mean that hotter and/or wetter conditions are required to produce a given CAPE

  • Distributional shifts in future midlatitudes CAPE can be well-captured given 3 regional mean changes: surface T and RH, and upper-level T

Atmospheric Science

Open Access

A Gradient Boosting Decision Tree Based Correction Model for AIRS Infrared Water Vapor Product

  • First Published: 23 July 2023
Key Points

  • A Gradient Boosting Decision Tree based correction model for Atmospheric Infrared Sounder (AIRS) infrared (IR) precipitable water vapor (PWV) products is developed and validated

  • The model can significantly enhance the all-weather accuracy of AIRS IR PWV products, especially in dry atmospheric conditions

  • The model reduces the root-mean-squared error of AIRS IR PWV by 21.43% with GNSS PWV, by 17.28% with radiosonde PWV, and by 18.13% with ERA5 PWV

Open Access

WWLLN Energetic Lightning Events Are Different From Optical Superbolts

  • First Published: 11 July 2023
Key Points

  • Optical and World Wide Lightning Location Network (WWLLN) Very Low Frequency energies are compared in superbolt cases

  • Optical superbolts are associated with large megaflashes typically found in stratiform clouds and do not reach the WWLLN 1 MJ threshold

  • WWLLN superbolts do not produce strong optical flashes, and arise in convective thunderstorm cores with low flash rates

Climate

Open Access

Growing Threats From Swings Between Hot and Wet Extremes in a Warmer World

  • First Published: 18 July 2023
Key Points

  • Temporally compounding heat and pluvial events occur about 15% more often than would be expected by chance

  • Increases in hot-wet compound events have largely been linked to warming

  • Vapor-pressure-deficit anomalies are a signature of heat-pluvial versus pluvial-heat sequences, a conclusion drawn from field significance tests

Hydrology and Land Surface Studies

Open Access

Interaction Between Tectonics and Climate Encoded in the Planform Geometry of Stream Networks on the Eastern Tibetan Plateau

  • First Published: 12 July 2023
Key Points

  • Branching angles of major stream networks on the eastern Tibetan Plateau vary systematically with climatic aridity and channel slopes

  • Climatic controls dominate over tectonic drivers in shaping the branching angles in the flat interior of the eastern Tibetan Plateau

  • Tectonic controls dominate over climate in shaping the branching angles in the steep margin of the eastern Tibetan Plateau

Space Sciences

Open Access

Anisotropy of the Near-Field Coseismic Ionospheric Perturbation Amplitudes Reflecting the Source Process: The 2023 February Turkey Earthquakes

  • First Published: 23 July 2023
Key Points

  • Mw 7.8 and Mw 7.7 February 2023 Turkey earthquakes produced typical ionospheric perturbations

  • For the first earthquake, we found small but significant difference in the perturbation amplitudes that cannot be explained by known factors

  • By assuming multiple sources along the fault and interference of acoustic waves from them, we can explain the observed azimuthal asymmetry

Open Access

Post-Sunset Field-Line Resonances at Equatorial Latitudes Observed by Swarm

  • First Published: 13 July 2023
Key Points

  • Field line resonances (FLRs) are identified at the lowest magnetic latitude ever reported

  • The fundamental frequency of our events decreases with increasing magnetic latitude in a uniform trend

  • FLRs detected at conjugate latitudes by two spacecraft at the equatorial ionosphere

Oceans

Open Access

Asymmetry Between Positive and Negative Phases of the Pacific Meridional Mode: A Contributor to ENSO Transition Complexity

  • First Published: 23 July 2023
Key Points

  • Pacific Meridional Mode (PMM) events can be divided into tropical-forced successive events and extratropical-forced stochastic events

  • Successive PMM events are negatively asymmetric, whereas stochastic ones are positively asymmetric

  • Opposite asymmetry of two types of PMM events, respectively, is conducive to more frequent persistent La Niñas and episodic El Niños

Atmospheric Science

Open Access

A Record-Breaking Cyclone Over the Southern Ocean in 2022

  • First Published: 26 July 2023
Key Points

  • The strongest cyclone ever recorded worldwide since 1980 occurred in the Amundsen-Bellingshausen Seas (ABS) in October 2022

  • The event formed from an interplay of dynamical and thermodynamical processes, including strong upper-level forcing and latent heat release

  • This cyclone is representative of a significant increase in extreme cyclones over the Southern Ocean in recent years, especially in the ABS

Open Access

Siege in the Southern Stratosphere: Hunga Tonga-Hunga Ha'apai Water Vapor Excluded From the 2022 Antarctic Polar Vortex

  • First Published: 25 July 2023
Key Points

  • Microwave Limb Sounder (MLS) trace gas data show that the Hunga Tonga-Hunga Ha'apai H2O plume was effectively excluded from the 2022 Antarctic polar vortex

  • Antarctic lower stratospheric vortex strength, size, and longevity were among the largest on record, but within the range of previous years

  • Antarctic chemical ozone loss in 2022 was unexceptional, with MLS ozone and related trace gases observed to be near average

Solid Earth

Open Access

Towards Inverse Modeling of Landscapes Using the Wasserstein Distance

  • First Published: 26 July 2023
Key Points

  • The use of the Wasserstein distance for identifying optimal landscape evolution models is demonstrated

  • This approach can produce simple objective functions, simplifying the search for models that minimize data misfit

  • Accurate amplitudes and locations of uplift can be retrieved from synthetic landscapes generated using different initial conditions

Oceans

Open Access

Freshwater Contributions to Decadal Variability of the Indonesian Throughflow

  • First Published: 26 July 2023
Key Points

  • A global ocean model is used to show how freshwater impacts the decadal variability of transport through the main Indonesian Throughflow pathway

  • Wind-driven advection of South China Sea freshwater induces an upstream pressure gradient that reduces transport

  • Freshwater input is modulated by atmospheric circulation changes associated with Pacific decadal variability

Atmospheric Science

Open Access

The Influence of Weather Patterns and the Madden-Julian Oscillation on Extreme Precipitation Over Sri Lanka

  • First Published: 27 July 2023
Key Points

  • Extreme precipitation in Sri Lanka occurs most frequently in weather patterns associated with the northeast and second intermonsoon seasons

  • In weather patterns with the largest frequency of extreme precipitation events, extreme precipitation can persist for five consecutive days

  • The frequency of extreme precipitation events is enhanced in phases 1–4 of the Madden-Julian Oscillation

Solid Earth

Open Access

Lateral Variations Across the Southern San Andreas Fault Zone Revealed From Analysis of Traffic Signals at a Dense Seismic Array

  • First Published: 11 July 2023
Key Points

  • We detect frequent seismic signals from rail and road traffic in a dense array across the southern San Andreas fault zone

  • We use the traffic signals to image shallow structural properties across the Banning and Mission Creek fault strands

  • The resolved velocity and density contrasts across the Mission Creek fault suggest it is the main active strand of the Southern San Andreas Fault in the area

Climate

Open Access

Decadal Changes in the Linkage Between Autumn Sea Ice and the Winter Eurasian Temperature in the 20th Century

  • First Published: 18 July 2023
Key Points

  • The linkage between autumn Barents-Kara sea ice and winter Eurasian temperature showed decadal changes in the 20th century and is only significant in recent decades

  • The stratospheric pathways and winter Ural Blocking activities can serve as bridges to link autumn sea ice and winter Eurasian temperature variability

  • Coupled Model Intercomparison Project models with realistic stratospheric pathways can capture the observed multi-decadal evolution of autumn sea ice-winter Eurasian temperature linkage

Oceans

Open Access

A Lagrangian Estimate of the Mediterranean Outflow's Origin

  • First Published: 11 July 2023
Key Points

  • Eighty-six percent of Mediterranean outflow originates from the Gulf of Lions, and 13% originates from the Strait of Sicily

  • These two components of the outflow have distinct T-S distributions at the origin, but the distinction is lost when Gibraltar is reached

  • Median transit times to the Strait of Gibraltar are 5 years from the Gulf of Lions and 8 years from the Strait of Sicily

Solid Earth

Open Access

The 2022 Eruption of Wolf Volcano, Galápagos: The Role of Caldera Ring-Faults During Magma Transfer From InSAR Deformation Data

  • First Published: 23 July 2023
Key Points

  • Interferometric synthetic aperture radar data are used to study ground deformation before, during and after the 2022 Wolf eruption

  • A ring fault opening/closure model fits ground deformation of the caldera well

  • Asymmetric opening of the ring fault promotes flank eruptions at Wolf volcano

Atmospheric Science

Open Access

On the Relationship Between Reliability Diagrams and the “Signal-To-Noise Paradox”

  • First Published: 18 July 2023
Key Points

  • The exact relationship between the “signal-to-noise paradox” and standard measures of forecast reliability has remained unclear

  • It is shown that the “paradox” is equivalent to the slope of reliability diagrams exceeding 1, assuming linearity/Gaussianity

  • The value of reliability diagrams as a diagnostic tool for understanding the “paradox” better is discussed

Oceans

Open Access

Response of Future Summer Marine Heatwaves in the South China Sea to Enhanced Western Pacific Subtropical High

  • First Published: 20 July 2023
Key Points

  • Increasing variability in the western Pacific subtropical high (WPSH) leads to more frequent, stronger WPSH events in future projections

  • The total days and intensity of summer marine heatwaves (MHWs) in the South China Sea (SCS) show different responses to the enhanced WPSH

  • Total days of summer MHWs in the SCS increase with the strengthened WPSH, resulting in a high coral bleaching risk

Hydrology and Land Surface Studies

Open Access

Sediment Exchange Across Coastal Barrier Landscapes Alters Ecosystem Extents

  • First Published: 17 July 2023
Key Points

  • Cross-landscape interactions are explored in new model framework connecting entire barrier system from shoreface to mainland forest

  • Simulations suggest barrier migration leads to rapid back-barrier marsh loss, while barrier stability enables back-barrier marsh recovery

  • Bay extent is insensitive to sea-level rise rates because of offsetting responses from barrier migration and marsh-edge erosion processes

Atmospheric Science

Open Access

Non-Monotonic Feedback Dependence Under Abrupt CO2 Forcing Due To a North Atlantic Pattern Effect

  • First Published: 24 July 2023
Key Points

  • Effective climate sensitivity (EffCS) and radiative feedbacks change non-monotonically with increasing CO2 concentrations

  • The non-monotonicity is associated with the formation of a sea-surface temperature cooling pattern over the North Atlantic

  • Results imply an overlooked radiative damping effect on global EffCS from the North Atlantic warming hole

Cryosphere

Open Access

Cold Season Rain Event Has Impact on Greenland's Firn Layer Comparable to Entire Summer Melt Season

  • First Published: 20 July 2023
Key Points

  • A cold-season rainstorm on the Greenland Ice Sheet demonstrates outsized impact of extreme weather events on evolution of the firn layer

  • Firn layer temperature quickly increased by up to 23°C, altering heat fluxes and requiring up to 2 months to thermally recover

  • The liquid water refrozen within the firn layer was ∼20%–100% of the amount of water refrozen during the previous summer

Solid Earth

Open Access

Temporal Variations in urn:x-wiley:00948276:media:grl66160:grl66160-math-0003 and urn:x-wiley:00948276:media:grl66160:grl66160-math-0004 Above a Megathrust Following Episodic Slow-Slip Events

  • First Published: 20 July 2023
Key Points

  • We estimated the long-term temporal variations in urn:x-wiley:00948276:media:grl66160:grl66160-math-0026 and urn:x-wiley:00948276:media:grl66160:grl66160-math-0027 at 20–45 Hz above the megathrust boundary of the Philippine Sea Plate

  • Both urn:x-wiley:00948276:media:grl66160:grl66160-math-0028 and urn:x-wiley:00948276:media:grl66160:grl66160-math-0029 exhibited temporal variations with about 1-year periodicity and spatiotemporal correlations with slow-slip events

  • Systematic differences between urn:x-wiley:00948276:media:grl66160:grl66160-math-0030 and urn:x-wiley:00948276:media:grl66160:grl66160-math-0031 may provide important constraints on attenuation mechanism enhanced by fluids

Planets

Open Access

Ultrahigh-Pressure Acoustic Velocities of Aluminous Silicate Glass up to 155 GPa With Implications for the Structure and Dynamics of the Deep Terrestrial Magma Ocean

  • First Published: 11 July 2023
Key Points

  • We have carried out acoustic wave velocity measurements of (Fe2+, Al)-bearing MgSiO3 glass up to 155 GPa

  • VS profile displays a change at 98 GPa induced by the Si-O coordination number change from 6 to 6+ followed by anomalously steeper trend

  • Results indicate the possible presence of highly dense Al, Fe2+-bearing Si-rich melts in the deep terrestrial magma oceans

Climate

Open Access

Increasing Intensity of Extreme Heatwaves: The Crucial Role of Metrics

  • First Published: 13 July 2023
Key Points

  • The most intense heatwaves of 1950–2021 considerably change if considering intensity indices either based on cumulative or averaged values

  • An appropriate measure of heatwave intensity should be based on cumulative indices allowing to better compare events of different length

  • The most intense heatwaves of 1950–1985 have become up to 10 times more frequent and up to three times more intense during 1986–2021

Atmospheric Science

Open Access

Synergetic Effects of Isoprene and HOx on Biogenic New Particle Formation

  • First Published: 11 July 2023
Key Points

  • Isoprene can suppress or enhance biogenic new particle formation (NPF) depending on the oxidation regime (OH vs. ozone oxidation)

  • Biogenic NPF is affected by both biogenic volatile organic compounds (VOCs) composition and HOx conditions

  • Previous laboratory studies showed seemingly contradicting theories because of the vastly different VOCs and HOx conditions

Open Access

Diurnal Variations on the Initiation Time and Intensification Rate of Rapidly Intensifying Tropical Cyclones

  • First Published: 11 July 2023
Key Points

  • The rapid intensification (RI) of tropical cyclone (TC) is more likely to initiate in the early morning and lasts ∼42 hr on average

  • TC intensification rates of RI events slightly peak in the late afternoon but with a marginal diurnal amplitude

  • Inner-core deep convection likely plays a role in the RI initiation as they are diurnally in phase

Space Sciences

Open Access

Fast Plasma Drifts in the High Latitude Ionosphere

  • First Published: 20 July 2023
Key Points

  • Fast plasma drifts larger than 5 km/s are common in high-latitude ionosphere at all local times, as observed by the Dynamics Explorer-2 Vector Electric Field Instrument

  • The drifts are mostly observed at 64°–82° inv.lat, with some events below 60° in the pre-midnight sector during enhanced magnetic activity

  • The observations show a seasonal dependence such that the faster plasma drifts tend to occur over the dark (winter) hemisphere

Oceans

Open Access

Deconstructing Future AMOC Decline at 26.5°N

  • First Published: 20 July 2023
Key Points

  • Future Atlantic Meridional Overturning Circulation decline is deconstructed by quantifying changes in the Gulf Stream, Deep Western Boundary Current (DWBC), and gyre recirculation

  • In a high emission scenario, Coupled Model Intercomparison Project Phase 6 models show a Gulf Stream weakening of 29% and a DWBC weakening of 47% at 26.5°N by the end of the century

  • 33% of the Gulf Stream weakening is due to changes in winds

Solid Earth

Open Access

Porphyry Copper Deposit Formation: Identifying Garnet and Amphibole Fractionation With REE Pattern Curvature Modeling

  • First Published: 23 July 2023
Key Points

  • Analysis of rare earth element pattern curvature distinguishes between amphibole and garnet fractionation better than element ratios like Dy/Yb or Dy/Dy*

  • Polybaric differentiation or plagioclase fractionation is unlikely to overprint a pre-existing garnet signature

  • We find that garnet fractionation is not necessary for porphyry copper deposit formation

Climate

Open Access

500-Year Periodic Vegetation and Monsoonal Climate Oscillations During the Last Deglaciation in East Asia

  • First Published: 10 July 2023
Key Points

  • Orbital-scale climate warming is evidenced by alterations in broadleaved forests and boreal coniferous forests with tundra steppe

  • Millennial- to centennial-scale vegetation changes in response to monsoonal climate change in East Asia

  • ∼500-yr vegetation cycles are triggered by East Asian monsoon changes linked to the El Niño-Southern Oscillation

Cryosphere

Open Access

The Glacier-Climate Interaction Over the Tibetan Plateau and Its Surroundings During the Last Glacial Maximum

  • First Published: 20 July 2023
Key Points

  • Coupled modeling of the Last Glacial Maximum glaciers and climate over the Tibetan Plateau and its surroundings is necessary

  • The elevated glaciers blocked water vapor transport, reduced precipitation over most of TPS, and increased winter temperature in eastern TPS

  • The coupled glacial modeling decreases glacial area, and with changes in spatial distribution better matches the reconstructions

Oceans

Open Access

Overturning Pathways Control AMOC Weakening in CMIP6 Models

  • First Published: 17 July 2023
Key Points

  • The magnitude of 21st century Atlantic Meridional Overturning Circulation (AMOC) weakening in CMIP6 models is highly correlated with an AMOC pathway into the Indo-Pacific Ocean

  • The real-world “Indo-Pacific diffusive” AMOC pathway inferred from observation-based estimates is used to constrain future AMOC weakening

  • Under high-end greenhouse gas forcing, AMOC weakening based on this emergent constraint relationship ranges from 29% to 61% by 2100

Hydrology and Land Surface Studies

Open Access

Restratification in Late Winter Lakes Induced by Cabbeling

  • First Published: 20 July 2023
Key Points

  • The nonlinear freshwater equation of state leads to creation of a denser mass of water by mixing lighter masses of water (called cabbeling)

  • Cabbeling generates a large scale instability that effectively entrains fluid in a parallel shear flow transporting heat downwards

  • The cabbeling instability drives a competing process that also strengthens the stratification of the interface

Solid Earth

Open Access

Joint Bayesian Modeling of Velocity Break Points, Noise Characteristics, and Their Uncertainties in GNSS Time Series: Far-Field Velocity Anomalies Concurrent With Magmatic Activity in Iceland

  • First Published: 17 July 2023
Key Points

  • The lower limit of velocity change values, where reliable estimates can be derived, depends on noise characteristics of Global Navigation Satellite System time series

  • Increased rift-perpendicular movement before the 2014 Bárðarbunga dike intrusion is inferred with 95% confidence, 120 km north of it

  • Concurrent far-field velocity anomalies and near-field precursors may indicate coupling between distant volcanic systems at a plate boundary

Hydrology and Land Surface Studies

Open Access

Impact of Reservoirs on Local Precipitation-Temperature Coupling Relationships

  • First Published: 25 July 2023
Key Points

  • This study presents the first global-scale analysis of changes in precipitation-temperature coupling relationships caused by reservoirs

  • Reservoirs intensify the sensitivity of precipitation extremes to temperature and frequency of compound precipitation-temperature extremes

  • Reservoirs have the most pronounced climate impacts in warm and arid regions

Solid Earth

Open Access

The Rise and Fall of Laramide Topography and the Sediment Evacuation From Wyoming

  • First Published: 20 July 2023
Key Points

  • Low-T-thermochronological data from type Laramide localities in Wyoming record burial of Laramide ranges and basins between ∼40 and 10 Ma

  • Regional incision and sediment evacuation after <10 Ma increased relief contributed to the attainment of modern topography

  • High-elevation low-relief surfaces in the Wind River Range developed from Laramide erosion and subsequent basin filling and continental-scale basin evacuation

Hydrology and Land Surface Studies

Open Access

How Bed Composition Affects Erosion by Debris Flows—An Experimental Assessment

  • First Published: 20 July 2023
Key Points

  • Small changes in water and clay content of the bed significantly affect debris-flow erosion processes and magnitude

  • Bed-water content increases erosion when the bed is nearly saturated, whereas for clay content an optimum exists for erosion around 3%–4%

  • Water and clay content of the bed affect debris-flow erosion by affecting bed pore pressure when the debris flow overrides the bed

Space Sciences

Open Access

Spectral Analysis of Ionospheric Density Variations Measured With the Large Radio Telescope in the Low-Latitude Region

  • First Published: 24 July 2023
Key Points

  • Giant Metrewave Radio Telescope (GMRT) can demonstrate an order of magnitude better sensitivity than GNSS-based TEC measurements in characterizing ionospheric fluctuations

  • The spectral analysis technique used with GMRT can detect multiple MSTIDs and smaller-scale structures simultaneously

  • GMRT can detect ionospheric variations as small as 10 km. The study also showed waves changing direction unexpectedly during sunrise time

Atmospheric Science

Open Access

Asymmetrical Modulation of the Relationship Between the Western Pacific Pattern and El Niño–Southern Oscillation by the Atlantic Multidecadal Oscillation in the Boreal Winter

  • First Published: 25 July 2023
Key Points

  • The connection between El Niño–Southern Oscillation (ENSO) and the western Pacific pattern (WP) varies markedly in different Atlantic Multidecadal Oscillation (AMO) phases

  • A robust connection between ENSO and the WP in the boreal winter can only be observed during the negative AMO phase

  • The AMO influences the ENSO-WP relationship via modulating the ENSO amplitude and the associated change in atmospheric convection

Oceans

Open Access

Impacts of a Cascadia Subduction Zone Earthquake on Water Levels and Wetlands of the Lower Columbia River and Estuary

  • First Published: 13 July 2023
Key Points

  • Earthquake-induced subsidence results in the movement of ∼93% of intertidal habitat to lower habitat zones

  • Post earthquake, tidal range increases by up to 0.25 m in channels; capturing such changes requires a dynamic model

  • Both subsidence and changes in tidal range alter habitats, especially sandflats and low marshes

Hydrology and Land Surface Studies

Open Access

Cold-Season Methane Fluxes Simulated by GCP-CH4 Models

  • First Published: 17 July 2023
Key Points

  • Cold-season methane (CH4) emissions simulated by 16 Global Carbon Project-CH4 wetland models were analyzed

  • Most models underestimate the cold-season emissions in comparison with observational data

  • Further model improvement by including cold-season processes is required to reduce the model bias and uncertainty

Atmospheric Science

Open Access

Tug-Of-War on Idealized Midlatitude Cyclones Between Radiative Heating From Low-Level and High-Level Clouds

  • First Published: 14 July 2023
Key Points

  • Radiative heating from high clouds leads to a stronger cyclone, radiative heating from low clouds leads to a weaker cyclone

  • Because of this tug-of-war, the overall effect of cloud-radiative heating can be a stronger or weaker cyclone

  • The radiative impact of clouds can be understood from the effect on static stability

Climate

Open Access

Drivers of Dry Day Sensitivity to Increased CO2

  • First Published: 26 July 2023
Key Points

  • AGCM simulations are used to split the dry day response to increased CO2 into fast adjustment versus slower uniform and patterned SST effects

  • None of the three components consistently dominates the global land response of dry days across the selected CMIP6 models

  • The uniform SST warming dominates the regional anomalies, which however do not scale with global warming across the multi-model ensemble

Space Sciences

Open Access

Investigating the Occurrence of Kelvin-Helmholtz Instabilities at Jupiter's Dawn Magnetopause

  • First Published: 14 July 2023
Key Points

  • There is evidence of Kelvin-Helmholtz instability (KHI)-driven waves along Jupiter's dawn flank magnetopause during the Juno prime mission

  • 24 (38.7%) crossings satisfied the KHI condition and 38 (61.3%) crossings did not satisfy the KHI condition

  • Magnetopause crossings that satisfied the KHI condition had, in general, larger velocity shears than those that did not

Atmospheric Science

Open Access

First High-Speed Video Camera Observations of a Lightning Flash Associated With a Downward Terrestrial Gamma-Ray Flash

R. U. Abbasi M. M. F. Saba J. W. Belz P. R. Krehbiel W. Rison N. Kieu D. R. da Silva M. A. Stanley Dan Rodeheffer J. Remington J. Mazich R. LeVon K. Smout A. Petrizze T. Abu-Zayyad M. Allen R. Arimura E. Barcikowski D. R. Bergman S. A. Blake I. Buckland B. G. Cheon M. Chikawa T. Fujii K. Fujisue K. Fujita R. Fujiwara M. Fukushima G. Furlich N. Globus R. Gonzalez W. Hanlon N. Hayashida H. He K. Hibino R. Higuchi K. Honda D. Ikeda N. Inoue T. Ishii H. Ito D. Ivanov H. Iwakura A. Iwasaki H. M. Jeong S. Jeong C. C. H. Jui K. Kadota F. Kakimoto O. Kalashev K. Kasahara S. Kasami S. Kawakami K. Kawata I. Kharuk E. Kido H. B. Kim J. H. Kim J. H. Kim S. W. Kim Y. Kimura I. Komae Y. Kubota M. Kuznetsov Y. J. Kwon K. H. Lee B. Lubsandorzhiev J. P. Lundquist T. Matsuyama J. N. Matthews R. Mayta I. Myers S. Nagataki K. Nakai R. Nakamura T. Nakamura A. Nakazawa E. Nishio T. Nonaka S. Ogio M. Ohnishi H. Ohoka Y. Oku T. Okuda Y. Omura M. Ono A. Oshima S. Ozawa I. H. Park M. Potts M. S. Pshirkov D. C. Rodriguez C. Rott G. I. Rubtsov D. Ryu H. Sagawa N. Sakaki T. Sako N. Sakurai K. Sato T. Seki K. Sekino P. D. Shah Y. Shibasaki N. Shibata T. Shibata J. Shikita H. Shimodaira B. K. Shin H. S. Shin D. Shinto J. D. Smith P. Sokolsky B. T. Stokes T. A. Stroman K. Takahashi M. Takamura M. Takeda R. Takeishi A. Taketa M. Takita Y. Tameda K. Tanaka M. Tanaka S. B. Thomas G. B. Thomson P. Tinyakov I. Tkachev H. Tokuno T. Tomida S. Troitsky R. Tsuda Y. Tsunesada S. Udo T. Uehama F. Urban D. Warren T. Wong M. Yamamoto K. Yamazaki K. Yashiro F. Yoshida Y. Zhezher Z. Zundel
  • First Published: 20 July 2023
Key Points

  • Simultaneous recordings of a downward-directed terrestrial gamma-ray flash (TGF), high-speed video images, and radio emissions

  • TGF events occurred while the leader was already branching below cloud base and even when it was halfway in its propagation to ground

  • Energetic downward-directed TGFs were associated with fast downward leaders that produced high return stroke peak currents

Oceans

Open Access

Sources and Pathways of Glacial Meltwater in the Bellingshausen Sea, Antarctica

  • First Published: 17 July 2023
Key Points

  • Meltwater pathways in the Bellingshausen Sea, Antarctica, are explored using observations from gliders and a high-resolution regional model

  • Meltwater observed at different densities originates from different ice shelves: lighter meltwater layers originate from eastern ice shelves

  • Meltwater from different ice shelves is distinguished by different turbidity signatures, suggestive of different biogeochemical properties

Atmospheric Science

Open Access

Assessing Convective-Stratiform Precipitation Regimes in the Tropics and Extratropics With the GPM Satellite Radar

  • First Published: 20 July 2023
Key Points

  • Areal coverage and echo-top heights of stratiform rain and warm- and cold-topped convection indicate strong geographic variability

  • Stratiform rain fraction is 45% and 85% in the tropics and midlatitudes, respectively, with a rapid transition in the subtropics

  • Statistical analysis suggests unique interactions between cold-top convection and stratiform precipitation in the tropics and extratropics

Oceans

Open Access

The Satellite-Observed Linkages Between Large-Scale Climate Fluctuations and Mesoscale Eddy Movements in the North Pacific

  • First Published: 26 July 2023
Key Points

  • Mesoscale eddies can move faster/slower as a result of the large scale ocean circulation induced by the climate fluctuations

  • Causality analysis verifies that climate fluctuations can modulate eddy propagation speed

  • Large scale climate fluctuations can affect the mass, heat and salt transport by eddy advection in the different climate phases

Solid Earth

Open Access

New Insights Into the Relationship Between Mass Eruption Rate and Volcanic Column Height Based On the IVESPA Data Set

  • First Published: 18 July 2023
Key Points

  • We provide empirical scaling relationships between mass eruption rate (MER) and column height using a new database with 134 volcanic events

  • We constrain bespoke relationships and their uncertainties for four height metrics to support ash dispersion forecasters and researchers

  • We detect no clear atmospheric influence on scaling relationships, highlighting required improvements of scaling models and the database

Atmospheric Science

Open Access

The First GECAM Observation Results on Terrestrial Gamma-Ray Flashes and Terrestrial Electron Beams

  • First Published: 13 July 2023
Key Points

  • During 9-month observation, Gravitational-wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) has detected 147 bright Terrestrial Gamma-ray Flashes (TGFs), 2 typical Terrestrial Electron Beams (TEBs), and 2 special TEB-like events

  • With novel detector design, GECAM can effectively classify TGFs and TEBs, and reveal their fine temporal features

  • We obtained a very high TGF-lightning association rate (∼80%) between GECAM and GLD360 in east Asia region

Climate

Open Access

How Credibly Do CMIP6 Simulations Capture Historical Mean and Extreme Precipitation Changes?

  • First Published: 18 July 2023
Key Points

  • Coupled Model Intercomparison Project Phase 6 (CMIP6) realistically simulates observed changes in mean and extreme precipitation in large parts of Europe and Asia and other land regions

  • In regions with moderate skill and observed precipitation subject to multi-decadal variations the availability of very large ensembles is beneficial

  • Lack of skill occurs primarily in regions where negative precipitation trends are observed but CMIP6 simulates increases

Space Sciences

Open Access

Statistical Evidence for Off-Equatorial Minimum-B-Pocket as a Source Region of Electron Cyclotron Harmonic Waves in the Dayside Outer Magnetosphere

  • First Published: 17 July 2023
Key Points

  • Dayside electron cyclotron harmonic (ECH) waves on bifurcated magnetic field lines are statistically analyzed according to their latitude distance from minimum-B-pocket

  • These dayside ECH waves have larger occurrence rates and amplitude in the vicinity of the off-equatorial minimum-B-pocket

  • The occurrence and amplitude of these dayside ECH waves are asymmetric relative to the off-equatorial minimum-B-pocket

Solid Earth

Open Access

Three-Dimensional Electrical Structure Beneath the Epicenter Zone and Seismogenic Setting of the 1976 Ms7.8 Tangshan Earthquake, China

  • First Published: 20 July 2023
Key Points

  • Detailed three-dimensional crustal structure beneath the Ms7.8 Tangshan earthquake zone is obtained

  • The seismotectonics comprised a resistive anomaly located east of the Tangshan fault (TSF), a resistive belt extending westward and the TSF

  • The Tangshan earthquake was triggered by the prevailing horizontal pushing force from the west and the local uplift of hot material

Open Access

Low-Degree Melt Metasomatic Origin of Global Upper Mantle Fe Isotope Fractionation

  • First Published: 25 July 2023
Key Points

  • Iron isotope study on continental alkali basalts verifies the global significance of low-degree melt metasomatism in causing upper mantle Fe isotope fractionation

  • Low-degree melt metasomatism is a globally effective process to concentrate heavy Fe isotopes at upper mantle conditions

  • The low-degree melt metasomatism associated Fe isotope fractionation could be both recent and ancient