• Issue

    Geophysical Research Letters: Volume 49, Issue 21

    16 November 2022

Issue Information

Free Access

Issue Information

  • First Published: 27 October 2022

Research Letter

Climate

Open Access

Stronger Response to the Aerosol Indirect Effect Due To Cooling in Remote Regions

  • First Published: 21 October 2022
Key Points

  • The forcing efficacy from an enhanced aerosol indirect effect is larger than unity

  • The aerosol indirect effect induces remote cooling at mid- to high-latitudes, in contrast to the local cooling from the direct effect

  • The different spatial patterns of temperature change from the aerosol direct and indirect effects excite different feedbacks

Oceans

Free Access

Monthly Gravity Field Solutions From Early LEO Satellites' Observations Contribute to Global Ocean Mass Change Estimates Over 1993∼2004

  • First Published: 21 October 2022
Key Points

  • New Tongji-LEO2021 solutions developed from Early Low Earth Orbit (LEO) satellites' observations are first used to estimate the global mean ocean mass changes for 1993–2004

  • LEO-derived global ocean mass changes are within a monthly mean error of 3.98 mm relative to Altimetry-Steric estimates

  • The ocean mass changes contribute ∼36% of the global mean total sea-level change rate (2.36 ± 0.30 mm/year) over 1993–2004

Planets

Open Access

Acoustics Reveals Short-Term Air Temperature Fluctuations Near Mars' Surface

  • First Published: 06 October 2022
Key Points

  • Sound speed derived temperature is used to study the microscale turbulence at an unprecedented short response time

  • Air temperature experiences fluctuations as high as ±7 K/s, which has never been reported in situ, nor resolved by mesoscale atmospheric models

  • Sonic temperature fluctuations follow the daytime turbulence pattern and find their origin in complex surface-atmosphere interactions

Solid Earth

Open Access

Development of Lattice-Preferred Orientations of MgO Periclase From Strain Rate Controlled Shear Deformation Experiments Under Pressure up to 120 GPa

  • First Published: 25 October 2022
Key Points

  • Strain rate controlled shear deformation experiments on MgO were conducted under lowermost mantle pressure (120 GPa) for the first time

  • Large strain deformation experiments on MgO show that the {100}<011> slip is dominant in the D″ layer

  • A {100}<011> slip of MgO by shear deformation results in VSH > VSV shear splitting, consistent with seismic observations in the D″ layer

Open Access

Small Magnitude Events Highlight the Correlation Between Hydraulic Fracturing Injection Parameters, Geological Factors, and Earthquake Occurrence

  • First Published: 25 October 2022
Key Points

  • We use supervised machine learning to investigate the relationship between hydraulic fracturing operation parameters and induced seismicity

  • Geological properties and a limited number of operational parameters predominantly influence the probability of an induced earthquake

  • The approach has the potential to guide detailed investigations of injection parameters critical for inducing earthquakes

Research Letters

Oceans

Free Access

The Ocean's Biological Pump: In Situ Oxygen Measurements in the Subtropical Oceans

  • First Published: 25 October 2022
Key Points

  • The geographic distribution of the downward flux of biological organic carbon from the upper ocean (the ocean's biological pump) is uncertain and difficult to determine from observations

  • T, S, and pO2 measurements from 21 profiling floats in the world's subtropical oceans are interpreted in terms of the net biological oxygen production in the upper ocean

  • The measured net biological oxygen flux is higher in the northern hemisphere subtropics than in the southern subtropics and correlated with surface-water iron concentration

Research Letter

Solid Earth

Free Access

The Impact of Plate Motions on Long-Wavelength InSAR-Derived Velocity Fields

  • First Published: 25 October 2022
Key Points

  • Rigid plate motions, coupled with line-of-sight variation, introduce long-wavelength spatial gradients in Interferometric Synthetic Aperture Radar (InSAR)-derived velocity maps

  • Plate motion effects dominate the long-wavelength components in InSAR velocities after ionospheric correction

  • Plate motion effects can be easily accounted for using plate motion models, improving long-wavelength deformation mapping from InSAR

Free Access

MCADAM: A Continuous Paleomagnetic Dipole Moment Model for at Least 3.7 Billion Years

  • First Published: 08 November 2022
Key Points

  • Continuous dipole moment models for the past 3.7–4.2 billion years are presented

  • Our model reproduces salient features of the paleomagnetic dipole field

  • Paleomagnetosphere estimates suggest Precambrian atmospheric shielding was much weaker than present day

Oceans

Free Access

Weakened Submesoscale Eddies in the Equatorial Pacific Under Greenhouse Warming

  • First Published: 31 October 2022
Key Points

  • Submesoscale eddies in the equatorial Pacific and their associated vertical heat flux are weakened under greenhouse warming

  • The weakened vertical submesoscale eddy heat flux under greenhouse warming acts as negative feedback on the El Niño-like warming pattern

Solid Earth

Open Access

Revealing Crustal Deformation and Strain Rate in Taiwan Using InSAR and GNSS

  • First Published: 18 October 2022
Key Points

  • This study combines Interferometric Synthetic Aperture Radar and Global Navigation Satellite System and produces high-resolution 3-D interseismic crustal velocities and strain rate estimates in Taiwan

  • Strain rate measurements show high surface strain cumulation along east and southwest Taiwan

  • The surface strain rates and the earthquake hazard models based on seismology and field study are in good agreement

Oceans

Free Access

Nitrous Oxide Consumption in Oxygenated and Anoxic Estuarine Waters

  • First Published: 17 October 2022
Key Points

  • Nitrous oxide (N2O) consumption rates were measured in the oxygenated and anoxic waters of the Chesapeake Bay, revealing large N2O consumption potential

  • N2O consumption rates showed a strong dependence on oxygen and N2O substrate concentration

  • Clade II nitrous oxide reductase genes were more abundant than clade I nitrous oxide reductase genes in the Chesapeake Bay

Planets

Free Access

Mars-Ward Ion Flows in the Martian Magnetotail: Mars Express Observations

  • First Published: 08 November 2022
Key Points

  • Mars-ward ion flows in the magnetotail occur more frequently and with a higher flow flux during solar maximum

  • The occurrence rate and flux of planetward flows at Martian magnetotail are relatively lower than the case at Venusian magnetotail

  • A strong correlation between crustal fields and Mars-ward flows is identified

Cryosphere

Open Access

Quantifying Ice-Sheet Derived Lead (Pb) Fluxes to the Ocean; A Case Study at Nioghalvfjerdsbræ

  • First Published: 25 October 2022
Key Points

  • Helium and neon show strong evidence for a subglacial source of Pb discharging onto the NE Greenland Shelf

  • Contrasting inflowing and outflowing waters beneath the floating ice tongue of Nioghalvfjerdsbræ shows a 2-3-fold dPb enrichment

  • The dissolved Pb flux from Nioghalvfjerdsbræ (2.2 ± 1.4 Mg·yr−1) is comparable to small Arctic rivers, with ∼90% of a sedimentary origin

Planets

Open Access

An Evolved Early Crust Exposed on Mars Revealed Through Spectroscopy

  • First Published: 10 October 2022
Key Points

  • Nine feldspar-rich regions of intermediate silica compositions were identified in Terra Sirenum/Cimmeria (TSC)

  • The feldspar-rich terrains are excavated crustal materials supporting a pre-Noachian evolved crust at TSC

  • An early evolved crust on Mars suggests that early crusts in the solar system were not restricted to basaltic

Climate

Free Access

Hurricanes and Anomalous Heat in the Caribbean

  • First Published: 25 October 2022
Key Points

  • Areas around tropical cyclones have heat index (HI) values significantly warmer than average, a result insensitive to storm strength

  • Positive HI anomalies occur after the cyclones passage in all storms; the maximum anomalies range from 0.3°C to 5.2°C

  • Anomalous heat can be observed in areas 100s of kilometers away from the central location of the tropical storm

Solid Earth

Free Access

Velocity Gradients Below the 410-km Discontinuity Beneath Eastern Asia and Its Implication on Water Content Distribution

  • First Published: 25 October 2022
Key Points

  • An abnormal X phase is identified from seismic waves sampling the mantle transition zone beneath south and southwest China

  • The existence/lack of the X phase is controlled by the velocity gradient below the 410-km discontinuity

  • The existence of the X phase indicates a uniform water content; the lack of it suggests a water content decreasing from 410-km downward

Climate

Free Access

Multidecadal Variation in the Seasonal Predictability of Winter PNA and Its Sources

  • First Published: 21 October 2022
Key Points

  • The Pacific-North American (PNA) is more predictable at the two ends of the 20th century since it is mainly linked to El Niño-Southern Oscillation (ENSO)

  • During the middle 20th century, the seasonal predictability of the PNA was affected by both ENSO and the Pacific decadal oscillation

  • The air-sea coupling process in the extratropical North Pacific is important for improving the seasonal prediction of the PNA

Oceans

Open Access

Changes in Deep Ocean Contribute to a “See-Sawing” Gulf Stream Path

  • First Published: 31 October 2022
Key Points

  • The Gulf Stream (GS) path has an oscillating spatial pattern, which is induced by declining water density at deep layer

  • A new index for the strength of GS is proposed

Solid Earth

Free Access

New Inferences on Magma Dynamics in Melilitite-Carbonatite Volcanoes: The Case Study of Mt. Vulture (Southern Italy)

  • First Published: 07 November 2022
Key Points

  • Micro-thermometric analyses show the occurrence of high-density CO2-rich fluid inclusions hosted by minerals within wehrlite xenoliths

  • Ascent rate between melilitite-carbonatite (≈20 m/s) and kimberlite (≈45 m/s) magma is comparable

  • Melilitite-carbonatite volcanoes can be hazardous even after long time of quiescence (>105 years)

Planets

Open Access

The Arid Regolith of the Moon

  • First Published: 31 October 2022
Key Points

  • The upper limit for water in the lunar exosphere is ∼3 molecules/cc

  • The lunar exosphere does not transport meteoritic water to polar cold traps

  • Lunar regolith is arid

Oceans

Open Access

Chromium Cycling in Redox-Stratified Basins Challenges δ53Cr Paleoredox Proxy Applications

  • First Published: 03 October 2022
Key Points

  • Non-quantitative Cr removal at the chemocline drives chromium (Cr) isotope fractionation and the accumulation of light Cr in euxinic deep waters

  • Authigenic sediment δ53Cr differs from overlying water, contrary to paleoproxy application assumptions, and is similar to continental crust

  • δ53Cr signals in these settings may therefore reflect internal redox processes and not fractionation due to oxidative subaerial weathering

Planets

Free Access

Constraining Early Mars Glacial Conditions From Paleodischarge Estimates of Intracrater Inverted Channels

  • First Published: 31 October 2022
Key Points

  • Paleodischarge estimates for individual intracrater inverted channel segments vary from ∼2 to 7,000 m3/s

  • High end discharges would require supraglacial melting rates of >2,000 mm/hr

  • Predicted range of paleodischarges and melting rates corresponds to either gradual or cataclysmic end-member warming scenarios

Cryosphere

Free Access

Abrupt Northern Baffin Bay Autumn Warming and Sea-Ice Loss Since the Turn of the Twenty-First Century

  • First Published: 31 October 2022
Key Points

  • A reduction in October northern Baffin Bay ice cover is observed around 2001 and is characterized by a westward retreat of the ice edge

  • The spatiotemporal shift in the ice cover coincided with observed warming of surface air and ocean temperatures to inhibit ice growth

  • An ocean model suggests the ice loss is spatially coherent with Atlantic water mass warming on the eastern flank of northern Baffin Bay

Atmospheric Science

Open Access

Heat Extremes Driven by Amplification of Phase-Locked Circumglobal Waves Forced by Topography in an Idealized Atmospheric Model

  • First Published: 31 October 2022
Key Points

  • The inclusion of topography in an idealized model setup yields global-scale slow-moving Rossby waves with preferred longitudinal locations

  • When these slow-moving Rossby waves amplify they lead to an increased frequency of concurrent heatwaves in preferred longitudinal locations

  • In the model, zonal wavenumbers 5 and 6 exhibit the strongest anomalies, which strongly impact temperature and heatwave frequency

Hydrology and Land Surface Studies

Free Access

Sediment Pickup Rate in Bare and Vegetated Channels

  • First Published: 31 October 2022
Key Points

  • Time-averaged bed-shear stress models significantly underestimated sediment pickup rate in vegetated channels

  • New turbulence-based models predicted sediment pickup rate in both bare and vegetated channels

  • Pickup rate resulting in either suspended load or bedload can be described by the same law

Planets

Free Access

Deducing Lunar Regolith Porosity From Energetic Neutral Atom Emission

  • First Published: 25 October 2022
Key Points

  • Reflection of solar wind protons from lunar regolith is simulated with SDTrimSP-3D

  • A precise agreement with spacecraft measurements of energetic neutral atom emission is only found for highly porous regolith structures

  • A lunar regolith porosity of urn:x-wiley:00948276:media:grl65047:grl65047-math-0002 is derived from solar wind proton reflection, which could also be applied to other airless bodies

Atmospheric Science

Open Access

Future Changes in Active and Inactive Atlantic Hurricane Seasons in the Energy Exascale Earth System Model

  • First Published: 31 October 2022
Key Points

  • We project future change in active and inactive Atlantic hurricane seasons driven by El Niño—Southern Oscillation and the Atlantic Meridional Mode

  • Future Atlantic tropical cyclone (TC) frequency increases during active and inactive seasons, with greater increases in the active season

  • Increased potential intensity and relative humidity and decreased shear support stronger and more frequent TCs in the future

Free Access

Improvement of the Aerosol Forecast and Analysis Over East Asia With Joint Assimilation of Two Geostationary Satellite Observations

  • First Published: 21 October 2022
Key Points

  • A new quality-control method making the best quality of Fengyun-4A aerosol products for data assimilation is proposed

  • It is the first attempt to simultaneously assimilate aerosol optical thicknesses (AOTs) from two geostationary satellites with an advanced data assimilation system

  • Jointly assimilating AOTs of two geostationary satellites significantly enhances model performances over East Asia

Planets

Free Access

Planetary Waves Traveling Between Mars Science Laboratory and Mars 2020

  • First Published: 21 October 2022
Key Points

  • Both rovers observe 1.5–30 sol waves in multiple variables during northern spring with amplitudes agreeing with a reanalysis

  • Mars Science Laboratory (MSL) and Mars 2020 observations alternatively correlate and anti-correlate, pointing to planetary waves originating in different hemispheres

  • North-south propagating waves vacillate between first occurring at MSL or Mars 2020, suggesting waves grow from multiple types of instabilities

Oceans

Free Access

Airborne Observations of Shoaling and Breaking Internal Waves

  • First Published: 07 November 2022
Key Points

  • We present novel high-resolution airborne observations of the kinematics of shoaling and breaking internal waves

  • We find that the active breaking regions of the internal wave drive strong convergence/divergence

  • The spatial variability of the internal wave is shown to occur over a broad range of scales, from a few to a few hundred meters

Planets

Open Access

Complex Crater Formation by Oblique Impacts on the Earth and Moon

  • First Published: 21 October 2022
Key Points

  • We have simulated the formation of complex impact craters at a range of impact angles and velocities

  • Complex craters formed at oblique angles are larger than existing scaling laws predict

  • The overall effect of impact obliquity on crater populations is not as strong as earlier calculations suggested

Climate

Free Access

Slowdown in Landfalling Tropical Cyclone Motion in South China

  • First Published: 31 October 2022
Key Points

  • Translation speed of landfalling tropical cyclones in south China has experienced a significant slowdown by 1.2 m s−1 during 1979–2019

  • The slowdown is a balance of the opposite effects of the negative phase of the Pacific Decadal Oscillation and the Indian Ocean sea surface temperature warming

  • The results suggest that the effects of climate change and natural variability on tropical cyclone translation speed can offset each other

Cryosphere

Open Access

Modeling Ocean Wave Transfer to Ross Ice Shelf Flexure

  • First Published: 07 November 2022
Key Points

  • Model predictions of Ross Ice Shelf flexure in response to ocean waves, incorporating real shelf thickness and seabed profiles

  • Model validated against observations, and swell and infragravity waves found to generate maximum flexural strains of similar magnitude

  • Predictions will empower studies of ocean wave influence on crevasse expansion, rift propagation, and iceberg calving

Planets

Open Access

Influence of Planetary Surface Temperature on the Tectonic Transition From Heat Pipes

  • First Published: 31 October 2022
Key Points

  • High surface temperatures delay the transition from heat pipes

  • Lithospheric failure is highly sensitive to the rheological parameter space and is not solely controlled by the yield stress

  • The heat flow, mantle temperature, and time of the transition out of heat pipes are determined by the efficiency of subsolidus convection

Oceans

Open Access

Ultra-Oligotrophic Waters Expansion in the North Atlantic Subtropical Gyre Revealed by 21 Years of Satellite Observations

  • First Published: 21 October 2022
Key Points

  • The lowest chlorophyll-a waters in the North Atlantic Subtropical Gyre (NASTG) are spatially expanding and increasing in frequency, as seen by 21 years of satellite data

  • NASTG core shows a shift to a dominant quasi-permanent ultra-oligotrophic condition

  • Ocean warming's role in sharpening oligotrophy is more complex than local stratification increase only

Commentary

Climate

Open Access

ENSO Teleconnections More Uncertain in Regions of Lower Socioeconomic Development

  • First Published: 08 November 2022
Key Points

  • Uncertainty in historical El Niño Southern Oscillation teleconnections is examined using an ensemble reanalysis product

  • Regional climate responses to El Niño and La Niña are more uncertain in poorer regions

  • This inequality in climate information must be addressed to increase resilience to extremes

Research Letter

Solid Earth

Open Access

Episodic Slow Slip Hosted by Talc-Bearing Metasomatic Rocks: High Strain Rates and Stress Amplification in a Chemically Reacting Shear Zone

  • First Published: 31 October 2022
Key Points

  • Contrasting actinolite microstructures in talc-free and talc-bearing subduction interface metasomatic rocks record stress variations

  • Stress amplification in actinolite from talc-actinolite schist results from high strain rate deformation of surrounding talc

  • High strain rates reflect episodic slow slip localized in talc-actinolite schist under high pore fluid pressures during metasomatism

Planets

Open Access

First Assimilation of Atmospheric Temperatures From the Emirates Mars InfraRed Spectrometer

  • First Published: 10 October 2022
Key Points

  • We assimilate atmospheric temperature profiles from Emirates Mars Mission-Emirates Mars InfraRed Spectrometer (EMM-EMIRS) over a 79-sol period in Mars Year 36 shortly before northern summer solstice

  • EMIRS’ near-hemispheric spatial coverage is used to analyze complete weather systems; we deduce the structure and motion of a warm front

  • The horizontal wind diurnal cycle is retrieved by assimilation based on EMM-EMIRS’ extended local time coverage of atmospheric temperatures

Space Sciences

Open Access

On Magnetosheath Jet Kinetic Structure and Plasma Properties

  • First Published: 29 October 2022
Key Points

  • Ions in an observed jet exhibit complex distribution functions, with a cold/fast jet beam and hotter/slower background population

  • Jet interaction with the background magnetosheath is studied by comparing partial moments of the jet population with the full ion moments

  • The derived properties of the cold/fast population connect the jet's origin to upstream solar wind and foreshock structures

Oceans

Free Access

Obliquity Induced Latitudinal Migration of the Intertropical Convergence Zone During the Past ∼410 kyr

  • First Published: 10 November 2022
Key Points

  • Core U1483 surface seawater δ18O reflects precipitation at the southern margin of the Intertropical Convergence Zone (ITCZ)'s latitudinal displacement on the obliquity band

  • Obliquity dominated latitudinal migration of the ITCZ by modulating the North Atlantic sea ice cover

Space Sciences

Free Access

Statistics and Empirical Models of the Plasmasphere Boundaries From the Van Allen Probes for Radiation Belt Physics

  • First Published: 25 October 2022
Key Points

  • We deduce the electron plasma density from Electric Field and Waves and Electric and Magnetic Field Instrument Suite and Integrated Science measurements (2012–2019) and extract the plasmasphere boundaries

  • New plasmasphere boundary statistics and laws, binned by L, magnetic local time, and geomagnetic indices are generated to be used in space weather codes

  • A density-based boundary is more frequently defined than is a gradient-based boundary, and yields a more frequently applicable model

Atmospheric Science

Free Access

The Role of Wave Breaking in the Development and Subseasonal Forecasts of the February 2021 Great Plains Cold Air Outbreak

  • First Published: 21 October 2022
Key Points

  • The February 2021 cold air outbreak (CAO) involved an extended period of extremely cold air in the Great Plains of the United States

  • The event evolution featured two Rossby wave breaks; one in the East Siberian Sea and one in the Labrador Sea

  • Ensemble members of subseasonal dynamical models that captured the wave breaks produced more accurate forecasts of the CAO

Oceans

Free Access

Carbon Sequestration of the Middle Miocene Sunda Shelf Facilitated Global Climate Change

  • First Published: 31 October 2022
Key Points

  • Organic carbon (OC) burial on the Sunda Shelf is essential to the global carbon cycle during the middle Miocene

  • The OC burial rate of the Middle Miocene Climate Transition (MMCT) was faster than that of the Miocene Climatic Optimum

  • Expanded terrestrial carbon reservoirs and enhanced organic matter burial efficiency promoted the MMCT

Solid Earth

Open Access

Gas Migration Episodes Observed During Peridotite Alteration in the Samail Ophiolite, Oman

  • First Published: 18 October 2022
Key Points

  • This paper presents hydrophone array data from a borehole in an actively serpentinizing terrain contain acoustic signals from bubble swarms discharging into the hole

  • Free gas accumulates in the formation and migrates rapidly in discrete swarm episodes when a pressure threshold is reached

  • Results reveal a gas migration mechanism associated with peridotite alteration, a process which enhances the kinetics of peridotite weathering

Open Access

Ring Fault Slip Reversal at Bárðarbunga Volcano, Iceland: Seismicity During Caldera Collapse and Re-Inflation 2014–2018

  • First Published: 18 October 2022
Key Points

  • Fault motion reverses on the same fault structure between the eruptive and post-eruptive periods

  • Tightly constrained focal mechanisms show motion on steeply dipping faults

Cryosphere

Free Access

δ18O of O2 in a Tibetan Ice Core Constrains Its Chronology to the Holocene

  • First Published: 25 October 2022
Key Points

  • We present the profile of δ18O of paleoatmospheric O2 and its implied gas chronology of a Tibetan ice core

  • The trapped air δ18O synchronization with the Antarctic Siple Dome ice core yields an upper age limit of 9.799 ka

  • The age deduced from the trapped air δ18O confirms the Holocene origin of the Chongce ice core

Space Sciences

Free Access

In Situ Observations of Lower Hybrid Drift Waves at the Inner Edge of the Ring Current by the Van Allen Probe-A

  • First Published: 31 October 2022
Key Points

  • Lower hybrid drift (LHD) waves are locally excited through the lower hybrid drift instabilities due to diamagnetic drift with hot proton density gradient

  • LHD waves mainly exhibit uniform magnetic local time distribution inside plasmapause while others distribute near the dusk outside plasmapause

  • Our results confirm the necessity of distinguishing between fast magnetosonic waves and LHD waves in the inner magnetosphere

Oceans

Free Access

Three Types of Antarctic Intermediate Water Revealed by a Machine Learning Approach

  • First Published: 21 October 2022
Key Points

  • An unsupervised learning approach, the profile classification model (PCM), is applied to classify Argo temperature and salinity profiles

  • PCM identifies three types of Antarctic Intermediate Water (AAIW) in the Southern Ocean and reveals their locations and boundaries

  • The Polar Frontal Zone in the South Pacific sector is established as the source region for AAIW formation

Atmospheric Science

Free Access

Potential Urban Barrier Effect to Alter Patterns of Cloud-To-Ground Lightning in Beijing Metropolis

  • First Published: 21 October 2022
Key Points

  • The strong synoptic forcing, strong wind speed, and weak urban heat island were in favor of the formation of a barrier effect in the built-up area of Beijing

  • When thunderstorms passed over city, the bifurcation of low-level airflow and splitting of convergence line was a result of the urban barrier effect

  • The size of a city and its building density might influence the occurrence and strength of a barrier effect

Solid Earth

Free Access

Paleogeographic Reconstruction of the Paleozoic Lhasa Terrane Through Detrital Zircon Mixing Modeling

  • First Published: 31 October 2022
Key Points

  • Detrital zircon mixing modeling indicates that the Lhasa Permo-Carboniferous sediments came mainly from the Perth basin, Australia

  • The Paleozoic Lhasa terrane spanned the boundary interval between Australian Gondwana and Indian Gondwana

  • The inverse Monte Carlo modeling method based on large-n detrital zircon data can be used in paleogeographic reconstructions of continents

Atmospheric Science

Open Access

Integrated Dynamics-Physics Coupling for Weather to Climate Models: GFDL SHiELD With In-Line Microphysics

  • First Published: 01 November 2022
Key Points

  • A new integrated dynamics-physics coupling framework is designed to enhance dynamics-physics interaction and thermodynamic consistency

  • In-line microphysics coupling shows significant improvements to weather prediction skills in Geophysical Fluid Dynamics Laboratory System for High-resolution prediction on Earth-to-Local Domains

  • Integrated physics shows promise for improved simulation of high-impact weather events such as hurricane

Solid Earth

Open Access

Eikonal Tomography With Physics-Informed Neural Networks: Rayleigh Wave Phase Velocity in the Northeastern Margin of the Tibetan Plateau

  • First Published: 25 October 2022
Key Points

  • We present a method for eikonal tomography with physics-informed neural networks

  • We apply it to a dense seismic array in the northeastern Tibetan Plateau with good validation compared with traditional approaches

  • Traveltime reconstruction inversion mitigates traveltime measurement error and the number of traveltime sets can be significantly reduced

Climate

Open Access

Sustained Water Storage in Horn of Africa Drylands Dominated by Seasonal Rainfall Extremes

  • First Published: 10 October 2022
Key Points

  • Rising terrestrial water storage in Horn of Africa Drylands

  • Increasing high-intensity rainfall events, particularly during October-November-December season

  • Terrestrial water recharge correlates with seasonal high-intensity rainfall

Solid Earth

Open Access

Geochemical Evidence for Diachronous Uplift and Synchronous Collapse of the High Elevation Variscan Hinterland

  • First Published: 10 October 2022
Key Points

  • Sr/Y-La/Yb ratios of igneous rocks quantitatively track Variscan crustal thickness and elevation

  • Thick crust capable of supporting high elevations developed by ca. 350 Ma and expanded westward

  • Results consistent with chemical weathering of the Variscan hinterland as a contributor to late Paleozoic environmental change

Free Access

Simultaneous Rupture Propagation Through Fault Bifurcation of the 2021 Mw7.4 Maduo Earthquake

  • First Published: 08 November 2022
Key Points

  • Geodetic imaging, back-projection, multiple point source and finite fault inversions are conducted for the Maduo earthquake

  • We show a stable rupture speed (∼2.5 km/s) of the entire rupture and a simultaneous rupture through bifurcated fault branches

  • The stopping phase on the southern branch likely stopped the rupture on the northern branch

Planets

Open Access

Evidence for Amorphous Sulfates as the Main Carrier of Soil Hydration in Gale Crater, Mars

  • First Published: 31 October 2022
Key Points

  • The amorphous component of Gale crater soils contains hydrated sulfates

  • The Eolian dust deposits are not the carrier of the identified hydrated sulfates

  • Water-limited acidic conditions may have led to the formation of these phases

Cryosphere

Open Access

Rapid and Gradual Permafrost Thaw: A Tale of Two Sites

  • First Published: 18 October 2022
Key Points

  • Changes in the state of permafrost can be highly variable in both space and time

  • Disturbance or changes in climate and precipitation influence the long-and short-term trajectory of permafrost and seasonally frozen ground

  • Geophysical measurements and monitoring complement direct permafrost observations by providing high resolution information at depth

Solid Earth

Free Access

Nonlinear Earthquake Response of Marine Sediments With Distributed Acoustic Sensing

  • First Published: 31 October 2022
Key Points

  • AutoCorrelation Functions (ACFs) of earthquakes recorded by a distributed acoustic sensing (DAS) experiment exhibit phase delays with increasing ground motions

  • ACF phase delays are converted to relative velocity drops in the medium that characterize soil nonlinearity

  • DAS is used to infer the nonlinear behavior of soils with an unprecedented spatial resolution

Climate

Open Access

Hydrothermal Ore Deposits Record the Oxygen Isotope Composition of Meteoric Paleo-Waters in the San Juan Volcanic Field, Colorado, USA

  • First Published: 17 October 2022
Key Points

  • Continental hydrothermal systems record meteoric water oxygen isotope compositions over broad space- and time-scales

  • Isotopic alteration in hydrothermal systems in the San Juan Volcanic Field, Colorado, USA provides a test of this approach

  • Inverse modeling suggests a decrease in meteoric oxygen isotope ratios between 23 and 15 Ma, consistent with 2–3 km of surface uplift

Cryosphere

Open Access

Hydraulic Conditions for Stick-Slip Tremor Beneath an Alpine Glacier

  • First Published: 21 October 2022
Key Points

  • Seismogenic stick-slip tremor occurs at the confluence of two subglacial channels during diurnal high-melt periods on an Alpine glacier

  • During tremor, the seismic moment released by stick-slip sliding is ∼10 times higher than outside of tremor periods

  • An extended spring-loaded slider-block model describes tremor activity with asperity loading from viscous creep and cavity formation

Open Access

Contrasting Export of Particulate Organic Carbon From Greenlandic Glacial and Nonglacial Streams

  • First Published: 31 October 2022
Key Points

  • Particulate organic carbon (POC) carried by glacial Zackenberg river shows uniform composition despite diverse inputs from tributaries

  • Geology and hydrologic conditions control POC composition in small periglacial streams with rain events eroding more ancient carbon

  • Organic matter in soils and river sediments throughout Zackenberg valley is largely associated with minerals

Oceans

Free Access

Millennial Variability in Intermediate Ocean Circulation and Indian Monsoonal Weathering Inputs During the Last Deglaciation and Holocene

  • First Published: 31 October 2022
Key Points

  • We present a 17 kyr record of foraminiferal Nd isotopes from the intermediate-depth northern Indian Ocean with a resolution of ∼200 years

  • Both regional Himalayan weathering inputs and intermediate water advection from the Southern Ocean influenced the record

  • Different interhemispheric relationships are revealed between Antarctic Intermediate Water and the Indian Summer Monsoon during the last deglaciation compared to the Early Holocene

Solid Earth

Open Access

How Clay Mineral Assemblages Affect Instability on the Upper Slope of the Hikurangi Subduction Zone, New Zealand

  • First Published: 31 October 2022
Key Points

  • Hikurangi trench-slope sediments, including muds within the Tuaheni landslide complex, contain high concentrations of detrital smectite

  • Smectite is abundant enough to reduce the bulk sediment's coefficient of friction, with little stratigraphic variability

  • The homogeneous mud composition results from strong currents and does not change significantly along inferred slip surfaces or weak layers

Space Sciences

Free Access

Non-Adiabatic Acceleration of Injected Electrons in the Inner Magnetosphere: Joint Observations by the Van Allen Probe and the BeiDa Imaging Electron Spectrometer

  • First Published: 21 October 2022
Key Points

  • Substorm injection of energetic electrons was simultaneously observed by radially separated spacecraft within the geosynchronous distance

  • The radial phase space density gradient turned into negative by the arrival of the injected electrons

  • The negative phase space density gradient indicated a non-adiabatic acceleration of the injected electrons

Oceans

Open Access

Future Changes in Eddy Kinetic Energy in the California Current System From Dynamically Downscaled Climate Projections

  • First Published: 21 October 2022
Key Points

  • Eddy kinetic energy (EKE) is projected to increase throughout the California Current System by the end of the 21st century

  • Future changes in EKE are associated with a warmer, more stratified ocean

Open Access

In Situ Particle Measurements Deemphasize the Role of Size in Governing the Sinking Velocity of Marine Particles

  • First Published: 18 October 2022
Key Points

  • Ex situ studies typically find size to be a strong predictor of sinking velocity; strong correlations are rarely observed in situ however

  • Increased homogeneity of other particle characteristics ex situ (e.g., density, composition) are responsible for this discrepancy

  • Results suggest importance of these other factors when predicting particle sinking velocities and fluxes using size-scaling relationships

Open Access

Challenging Radiocarbon Chronostratigraphies in Central Arctic Ocean Sediment

  • First Published: 31 October 2022
Key Points

  • Fish otolith radiocarbon age distributions in surface sediments illustrate the mixing of Holocene and pre-Last Glacial Maximum populations

  • Low sedimentation rates, particle winnowing and sedimentary gaps may impact microfossil mixing and 14C chronologies

  • Published paleoclimate/paleoceanographic records from similar sites might thus require some reinterpretation

Planets

Open Access

Observation of a Core-Diffracted P-Wave From a Farside Impact With Implications for the Lower-Mantle Structure of Mars

  • First Published: 31 October 2022
Key Points

  • We have identified a core-diffracted wave from a farside impact

  • We infer the lower mantle P-wave velocity structure hitherto unconstrained

  • We find indications for a lower mantle structure that appears to be incompatible with a compositionally- and thermally-homogeneous mantle

Climate

Free Access

Urban-Rural Gradient in Urban Heat Island Variations Responsive to Large-Scale Human Activity Changes During Chinese New Year Holiday

  • First Published: 21 October 2022
Key Points

  • The urban heat island intensity (UHII) decreases by −0.19 K in the day and −0.30 K at night during the Chinese New Year (CNY) holiday over 31 capitals in China

  • The UHII reduction is more pronounced in city core (0.54 K) than in city periphery (0.071 K)

  • The CNY-holiday impacts on UHII differ greatly by climate zone and by hour of day

Free Access

The Mode-Water-Induced Interannual Variation of the North Pacific Subtropical Countercurrent and the Corresponding Winter Atmospheric Anomalies

  • First Published: 31 October 2022
Key Points

  • The interannual variation of subtropical countercurrent (STCC) velocity is closely related to the volume of low potential vorticity (PV) water in the western subsurface ocean in winter

  • With more subsurface low PV water masses Lagrangian tracked southwestwardly, an enhanced baroclinic current exists to the west of STCC

  • Accompanied by the sea surface temperature gradient anomalies near STCC, a corresponding interannual variation of atmospheric winter westerly jet was revealed