• Issue

    Geophysical Research Letters: Volume 49, Issue 5

    16 March 2022

Research Letter

Cryosphere

Free Access

A Weak Precipitation Sensitivity of Glacier Runoff

  • First Published: 21 February 2022
Key Points

  • Glacier runoff is relatively insensitive to the interannual variability of precipitation

  • The above property is independent of the climate setting of the glacier

  • A temperature-sensitive glacier runoff and a precipitation-sensitive off-glacier runoff determine the climate response of catchment runoff

Oceans

Free Access

Impact of Sea Ice Production off Sabrina Coast, East Antarctica

  • First Published: 24 February 2022
Key Points

  • High sea ice productivity during 2003–2015 resulted from intensified northward winds and sea ice drift, and interior divergence of pack ice

  • Minimum sea ice production and summer sea ice drift divergence suppressed Shelf Water formation during 2009–2011

  • An input of 157.5 Gt/yr of meltwater from local glaciers and ice shelves resulted in the overall freshening of subsurface Thermostat Water

Climate

Open Access

Increased Variability of Biomass Burning Emissions in CMIP6 Amplifies Hydrologic Cycle in the CESM2 Large Ensemble

  • First Published: 01 March 2022
Key Points

  • Increased biomass burning emissions variability in Coupled Model Intercomparison Project Phase 6 amplifies hydrologic cycle in Community Earth System Model version 2

  • Column-integrated precipitable water, evaporation, and precipitation all increase poleward of 40°N

  • Several moderating factors act to mitigate hydrologic cycle amplification

Space Sciences

Open Access

Reflection and Refraction of the L-O Mode 5 kHz Saturn Narrowband Emission by the Magnetosheath

  • First Published: 21 February 2022
Key Points

  • The 5-kHz narrowband emissions (NB) from Saturn can be reflected by density structures in the magnetosheath

  • Reflection leads to depolarization and trapping of NB inside Saturn's magnetosphere

  • The upper frequency limit of trapped NB depends on variations in the magnetosheath and the solar wind

Cryosphere

Open Access

Storstrømmen and L. Bistrup Bræ, North Greenland, Protected From Warm Atlantic Ocean Waters

  • First Published: 02 March 2022
Key Points

  • Storstrømmen Glacier, Greenland (27-cm sea level rise equivalent) stands in cold waters behind shallow bathymetry

  • The frontal regions are 100 m deeper than expected but access of warm Atlantic Intermediate Water (AIW) is limited by a wide and shallow ridge

  • Retreat of Storstrømmen and L. Bistrup Bræ glaciers has operated relatively independent of changes in AIW temperature in Dove Bugt

Atmospheric Science

Free Access

Cold Air Outbreaks Promote New Particle Formation Off the U.S. East Coast

  • First Published: 24 February 2022
Key Points

  • New particle formation is more prevalent off the U.S. East Coast in winter rather than summer

  • Ratio of particle number above 3 versus 10 nm peaks above cloud top regardless of season

  • Cold and dry conditions during cold air outbreaks coincide with new particle formation

Planets

Free Access

A Dynamo Simulation Generating Saturn-Like Small Magnetic Dipole Tilts

  • First Published: 09 March 2022
Key Points

  • We simulate Saturn's dynamo using an anelastic dynamo without a stably stratified layer

  • The model generates a magnetic field with an extremely small angle between the magnetic dipole axis and the planetary spin axis

  • Axisymmetric zonal flows and equatorially symmetric convection are the main factors pushing the dipole tilt angle to small values

Cryosphere

Free Access

Helheim Glacier's Terminus Position Controls Its Seasonal and Inter-Annual Ice Flow Variability

  • First Published: 21 February 2022
Key Points

  • Calving has been controlling Helheim's speed variability since 2007

  • Averaging the calving rate over 60 days does not change the glacier behavior significantly

  • Constraining a calving law is critical to model the future of Helheim's mass balance

Oceans

Open Access

Quality Not Quantity: Prioritizing the Management of Sedimentary Organic Matter Across Continental Shelf Seas

  • First Published: 07 March 2022
Key Points

  • Within most shelf sediments organic matter (OM) is generally of low reactivity (i.e., low labile OM content) and resistant to remineralization

  • Muddy nearshore sediments hold large quantities of high reactivity OM which is at risk of remineralization when disturbed

  • Policy interventions that seek to protect reactive OM should prioritize near-shore sediment OM over the resilient OM in many shelf seas

Atmospheric Science

Open Access

Improved Representation of Extratropical Cyclone Structure in HighResMIP Models

  • First Published: 16 February 2022
Key Points

  • The strength of cyclone wind speeds are underestimated by CMIP6 models

  • HighResMIP models represent the structure and intensity of cyclones better than CMIP6 models

  • Elements of the large-scale environment surrounding cyclones are not improved in HighResMIP simulations

Climate

Open Access

An Optimal Precursor of Northeast Pacific Marine Heatwaves and Central Pacific El Niño Events

  • First Published: 28 February 2022
Key Points

  • A large-scale precursor to Northeast Pacific marine heatwaves (MHWs) with anomalies in both the North and Tropical Pacific is identified

  • This optimal precursor includes initial sea surface height anomalies that are key to MHW growth

  • The initial condition leading to optimal development of Northeast Pacific MHWs can also lead to subsequent Central Pacific El Niño events

Oceans

Open Access

On Timescales and Reversibility of the Ocean's Response to Enhanced Greenland Ice Sheet Melting in Comprehensive Climate Models

  • First Published: 21 February 2022
Key Points

  • Sudden increase in Greenland freshwater release is turned into century scale change by deep ocean dynamics

  • Upper ocean responses to moderately enhanced freshwater release from Greenland reverse on the same timescale once release ceases

  • Ocean model formulation affects regional expressions but basin-scale responses are robust, so is the timing on decadal to centennial scales

Free Access

Linking the Subsurface Indian Ocean Dipole to Central Pacific ENSO

  • First Published: 02 March 2022
Key Points

  • Some subsurface Indian Ocean dipole (Sub-IOD) events occur in winter-to-spring, independent of the surface Indian Ocean Dipole

  • Central Pacific (CP) El Niño–Southern Oscillation (ENSO) events that peak in winter-to-spring are connected to these Sub-IOD events by inducing an anomalous Walker circulation

  • Only CP ENSO events with a westward-located sea surface temperature anomaly center favor Sub-IOD events in spring

Climate

Free Access

Effects of Improved Simulation of Precipitation on Evapotranspiration and Its Partitioning Over Land

  • First Published: 21 February 2022
Key Points

  • The underestimated ratio of transpiration (T) to evapotranspiration (ET) can be largely attributed to too frequent light rain

  • The improved rainfall intensity spectrum greatly impacts evapotranspiration by directly reducing wet leaf fraction and canopy evaporation

  • The associated changes in solar radiation and other factors also affect evapotranspiration by increasing vegetation transpiration

Solid Earth

Free Access

High-Temperature Equation of State of FeH: Implications for Hydrogen in Earth's Inner Core

  • First Published: 24 February 2022
Key Points

  • We obtained the P-V-T equation of state of FeH based on volume measurements up to 142 GPa and 3660 K using a diamond-anvil cell

  • ΔVH, the volume increase of Fe by H atom, was determined as functions of P and T, enabling estimates of the H content in non-magnetic FeHx

  • We estimate the maximum H content in the inner core and discuss the possible compositional range of the Fe-H-Si-S inner core

Open Access

Anisotropic Tomography and Dynamics of the Big Mantle Wedge

  • First Published: 07 March 2022
Key Points

  • The first 3-D radial anisotropy model beneath NE Asia is obtained

  • East-west structural variations in the big mantle wedge (BMW) are revealed

  • A possible convection pattern in the BMW is proposed

Climate

Free Access

Understanding the Complicated Relationship Between ENSO and Wintertime North Tropical Atlantic SST Variability

  • First Published: 21 February 2022
Key Points

  • A robust linkage between ENSO and wintertime NTA SST variability could be established by considering the previous summer NTA SST state

  • The NTA initial state is in part traced to the preceding ENSO conditions, and also partially attributable to the local disturbance

  • The understanding of the ENSO–wintertime NTA SST relationship has implications for extending the seasonal predictability for the NTA SST

Space Sciences

Free Access

Structure of Energy Precipitation Induced by Superbolt-Lightning Generated Whistler Waves

  • First Published: 15 February 2022
Key Points

  • The electron precipitation signature induced by a superbolt lightning event is modeled, which agrees with previous spacecraft observation

  • The precipitation is decomposed into contributions from different wave frequency components and resonance modes to study its structure

  • The spatiotemporal signature of global precipitation is analyzed. The total precipitation energy is >100x stronger than typical lightning

Oceans

Open Access

Simulated Twentieth-Century Ocean Warming in the Amundsen Sea, West Antarctica

  • First Published: 28 February 2022
Key Points

  • An ensemble of ice-ocean simulations is used to study conditions in the Amundsen Sea over the twentieth century

  • The simulations show a long-term ocean warming trend on the continental shelf, which is not yet clear in the shorter observational record

  • The trends are partly driven by anthropogenic forcing, suggesting the ocean and ice shelves may also be sensitive to future climate policy

Planets

Free Access

Downward Oxidant Transport Through Europa's Ice Shell by Density-Driven Brine Percolation

  • First Published: 10 February 2022
Key Points

  • We synthesize available observations and show that Europa's near-surface O2 abundance may be two times higher than previous estimates

  • Near-surface brines generated during the formation of chaotic terrains drain downward through the ice shell in porosity waves

  • More than 80% of surface oxidants entrained into the brines may be delivered to the internal ocean

Atmospheric Science

Free Access

First Super-Pressure Balloon-Borne Fine-Vertical-Scale Profiles in the Upper TTL: Impacts of Atmospheric Waves on Cirrus Clouds and the QBO

  • First Published: 02 March 2022
Key Points

  • Profiles from a long-duration balloon reveal equatorial waves with wide extent but very fine-vertical scales that are unresolved in models

  • 97% of the cirrus clouds observed in the upper tropical tropopause layer (above 17 km) are related to these waves

  • The analyzed waves provide strong QBO forces, pointing to a possible mechanism to improve the simulation of the QBO and its climate impacts

Space Sciences

Free Access

Ducted Chorus Waves Cause Sub-Relativistic and Relativistic Electron Microbursts

  • First Published: 28 February 2022
Key Points

  • We demonstrate the first electron microburst observation by spinning Electron Losses and Fields INvestigation CubeSats

  • We present a comparison between ducted and nonducted chorus-driven electron precipitation

  • Simulation shows ducted chorus cause electrons microbursts over energy 100s keV and above

Atmospheric Science

Free Access

Persistent Layers of Enhanced Gravity Wave Dissipation in the Upper Mesosphere Revealed From SABER Observations

  • First Published: 02 March 2022
Key Points

  • Gravity waves (GW) action and its scale height derived from Sounding of the Atmosphere using Broadband Emission Radiometry observations reveal persistent layers of enhanced GW dissipation over the past 20 years

  • The enhanced dissipation is mainly centered at 80–85 km with a vertical range of 8–20 km, and it can constrain GW dissipation in model

  • The enhanced dissipation occurs above the eastward (westward) jet in winter (summer) and around the wind reversals in spring and autumn

Free Access

Satellite Observations Reveal a Large CO Emission Discrepancy From Industrial Point Sources Over China

  • First Published: 28 February 2022
Key Points

  • Tropospheric Monitoring Instrument observations reveal a large Carbon monoxide (CO) emission discrepancy from industrial point sources over China

  • Regional emission inventory probably underestimated CO emissions of certain industrial point sources over China

  • Future CO satellite constellation together with monitoring local emissions could support environment policy

Hydrology and Land Surface Studies

Free Access

Human Impacts Overwhelmed Hydroclimate Control of Soil Erosion in China 5,000 Years Ago

  • First Published: 21 February 2022
Key Points

  • Hydroclimate controlled soil erosion before the mid-Holocene in China

  • Direct linkages between sediment accumulation rates and Chinese population were detected across China

  • Human impacts started to control soil erosion in China 5,000 years ago, at least 1,000 years earlier than the global average

Climate

Free Access

The Decadal Variation of Eastward-Moving Tropical Cyclones in the South China Sea During 1980–2020

  • First Published: 16 February 2022
Key Points

  • The number of eastward-moving tropical cyclones (TCs) in the South China Sea has experienced a decadal variation since 1980

  • The zonal shift of Western Pacific Subtropical High (WPSH) is the main factor of the decadal variation of eastward-moving TCs

  • The eastward-retreated WPSH together with strong intraseasonal oscillation favors TCs moving eastward during 1994–2004

Atmospheric Science

Open Access

Enhanced Nighttime Fog and Low Stratus Occurrence Over the Landes Forest, France

  • First Published: 21 February 2022
Key Points

  • Fog and low stratus (FLS) cloud cover is enhanced over the French Landes forest at night

  • FLS cloud cover enhancement is most pronounced in summer and fall

  • Low wind speed and low temperatures over the forest are potential drivers of FLS enhancement

Oceans

Free Access

Quasi-Antiphase Diel Patterns of Abundance and Cell Size/Biomass of Picophytoplankton in the Oligotrophic Ocean

  • First Published: 01 March 2022
Key Points

  • Picophytoplanktonic quasi-antiphase diel cycles in abundance and cell size/biomass are likely a general feature of the oligotrophic ocean

  • Grazing pressure on Prochlorococcus and Synechococcus is as high during the day as during the night

Atmospheric Science

Free Access

Asymmetric Warming/Cooling Response to CO2 Increase/Decrease Mainly Due To Non-Logarithmic Forcing, Not Feedbacks

  • First Published: 28 February 2022
Key Points

  • The global surface temperature responds asymmetrically to increased and decreased CO2 levels, in both abrupt and transient cases

  • Effective climate sensitivity is higher with warming (2×, 4×, 8×CO2) than with cooling (1/2×, 1/4×, 1/8×CO2), in two different coupled models

  • The non-logarithmic nature of the CO2 forcing is primarily responsible for the asymmetry, not the radiative feedbacks

Climate

Open Access

Rapid Growth of Large Forest Fires Drives the Exponential Response of Annual Forest-Fire Area to Aridity in the Western United States

  • First Published: 28 February 2022
Key Points

  • We developed a database of western United States wildfires and examined why annual forest area burned grows exponentially with aridity

  • Individual fires grow at compounding rates, so fire enlargement driven by aridification is most rapid among large fires

  • Approximately two-thirds of the increase in 1984–2019 forest burned area is shaped by each year's largest 10% of forest fires

Hydrology and Land Surface Studies

Open Access

The Impact of Intermittency on Bed Load Sediment Transport

  • First Published: 16 February 2022
Key Points

  • Sediment transport near the threshold of motion is intermittent, making it hard to measure average flux, which is crucial for predictions

  • We use bifurcation theory in the presence of multiplicative noise to understand and describe the intermittency

  • Applying this to flume experiments, we find a new way of measuring the threshold of motion and predicting when intermittency will be present

Atmospheric Science

Free Access

Feedback of Tropical Cyclones Over the Western North Pacific on La Niña Flavor

  • First Published: 28 February 2022
Key Points

  • The stronger (weaker) the tropical cyclones (TCs) over the western North Pacific (WNP), the more the eastern (central)-Pacific La Niña months

  • The TCs over the WNP affect La Niña flavor by modulating the Walker circulation and thermocline

  • TCs are shown to be essential to improve the prediction skill of the two flavors of La Niña events during the peak time

Open Access

Role of the Tropics in State-Dependent Improvements of US West Coast NOAA Unified Forecast System Precipitation Forecasts

  • First Published: 21 February 2022
Key Points

  • Nudging tropical fields in the Unified Forecast System toward the observed state improves wintertime Weeks 3–4 precipitation forecasts over the United States West Coast

  • A subset of initial states identified by multivariate k-means clustering exhibits greater precipitation forecast improvements with nudging

  • Improved simulation of tropical intraseasonal variability when a strong Aleutian Low is present leads to these greater forecast improvements

Space Sciences

Free Access

Quasi-Trapped Electron Fluxes Induced by NWC Transmitter and CRAND: Observations and Simulations

  • First Published: 24 February 2022
Key Points

  • CRAND is the main source of 200–700 keV quasi-trapped electrons at L = 1.7 when NWC transmitter is at dayside

  • For quasi-trapped 206 keV electrons at L = 1.7, pitch angle diffusion is the main source mechanism when NWC station operates at nightside

  • The urn:x-wiley:00948276:media:grl63824:grl63824-math-0001 from NWC needs to be approximately 10−6 to 10−5 s−1 to reproduce the satellite observations of quasi-trapped 206 keV electrons at L = 1.7

Cryosphere

Free Access

Arctic Snow Depth, Ice Thickness, and Volume From ICESat-2 and CryoSat-2: 2018–2021

  • First Published: 10 March 2022
Key Points

  • For 2018–2021, the decline in mean Arctic sea ice thickness of ∼0.28 m in spring is largely explained by ∼0.50 m thinning of multiyear ice

  • Satellite-derived snow depth estimates, when compared to climatology, provide a thinner Arctic ice thickness especially during the fall

  • Satellite records since 2003 show a loss of one-third of the winter sea ice volume driven by the decline in multiyear ice coverage

Space Sciences

Free Access

Immediate Impact of Solar Wind Dynamic Pressure Pulses on Whistler-Mode Chorus Waves in the Inner Magnetosphere

  • First Published: 07 March 2022
Key Points

  • A stronger solar wind pressure pulse has a greater likelihood to change the magnetospheric chorus amplitude particularly on the dayside

  • Positive (negative) pressure pules can immediately increase (decrease) chorus amplitudes in the inner magnetosphere

  • These pulses mainly alter the linear growth of chorus waves by modifying the source electron distributions in the inner magnetosphere

Free Access

Recurrent Large-Scale Solar Proton Events Before the Onset of the Wolf Grand Solar Minimum

  • First Published: 21 February 2022
Key Points

  • Multiple abrupt increases in carbon-14 content were found during the transition time of solar activity into the grand minimum state

  • They occurred at solar activity maximum or at the declining phase of solar cycles, suggesting that they originate from solar proton events

  • The Wolf minimum may provide a unique opportunity to potentially deepen the understanding of the solar dynamo

Climate

Open Access

Oceanic and Atmospheric Drivers of Post-El-Niño Chlorophyll Rebound in the Equatorial Pacific

  • First Published: 07 March 2022
Key Points

  • The observed post-El Niño chlorophyll anomaly, “chlorophyll rebound,” in the equatorial Pacific is successfully simulated in GFDL-ESM4.1

  • This rebound is primarily driven by surfacing high iron anomalies propagated from western Pacific via Equatorial Undercurrent

  • High dust-iron deposition anomalies arising from dry land conditions augment the post-El Niño chlorophyll rebound

Planets

Free Access

Nanophase Iron Particles Derived From Fayalitic Olivine Decomposition in Chang'E-5 Lunar Soil: Implications for Thermal Effects During Impacts

  • First Published: 21 February 2022
Key Points

  • Subsolidus fayalitic olivine decomposition forming unique vesicular nanophase iron particles in Chang'E-5 soils was confirmed

  • Nanophase iron particles in the uppermost olivine layer are embedded with numerous vesicles containing possible O2 or SiO component

  • Unique microstructural features on fayalitic olivine rims shed light on the diversity of space weathering effects on the lunar surface

Oceans

Open Access

Increasing Nutrient Fluxes and Mixing Regime Changes in the Eastern Arctic Ocean

  • First Published: 21 February 2022
Key Points

  • Nutrient fluxes are higher in the western compared with the eastern Laptev Sea

  • Episodic mixing above the slope might significantly contribute to Pan-Arctic vertical nitrate supply

  • In the central Laptev Sea, a thinning halocline and shoaling Atlantic Water indicate an emerging regime shift in line with Atlantification

Free Access

Topographic Stabilization of Ocean Rings

  • First Published: 09 March 2022
Key Points

  • Coherent surface-intensified vortices with scales greater than the radius of deformation are stabilized by rough bottom topography

  • The lifespan of large vortex rings increases with the increasing amplitude of bottom topography

  • A critical threshold of the depth variance exists, above which the vortices are linearly stable

Atmospheric Science

Free Access

Quantification of Electric Fields in Fast Breakdown During Lightning Initiation From VHF-UHF Power Spectra

  • First Published: 21 February 2022
Key Points

  • Electric fields that drive fast breakdown (FB) processes are quantified using 1–750 MHz VHF-UHF spectral measurements

  • FB spectra exhibit a −10 dB cutoff frequency of 430 MHz that implies an E-field of 2.0 Ek driving streamer growth inside the FB process

  • This field is >7 times higher than the large-scale field, implying that the FB process involves a narrow electrically conducting structure

Space Sciences

Free Access

Simultaneous Observations of EMIC-Induced Drifting Electron Holes (EDEHs) in the Earth's Radiation Belt by the Arase Satellite, Van Allen Probes, and THEMIS

  • First Published: 16 February 2022
Key Points

  • “EMIC-induced drifting electron hole (EDEH)” was simultaneously detected by four satellites in the radiation belt

  • The radial profiles of phase space density indicate the local losses of relativistic electrons caused by EMIC waves

  • Multisatellite observations reveal that the flux at L* = 5.2–5.4 gradually decreases in a few tens of minutes

Oceans

Free Access

Turbulent Mixing in the Barrier Layer of the Equatorial Pacific Ocean

  • First Published: 24 February 2022
Key Points

  • Direct turbulence measurements and data-based mixing estimates reveal high occurrence of BL mixing in the western-central equatorial Pacific

  • BL mixing is associated with significant cooling, salting, and deepening of the mixed layer, and cooling, salting, and weakening of the BLs

  • The frequent BL mixing shows regular seasonal and interannual variations and may impact the El Niño development via modulating SSTs

Solid Earth

Open Access

Continental Break-Up Under a Convergent Setting: Insights From P Wave Radial Anisotropy Tomography of the Woodlark Rift in Papua New Guinea

  • First Published: 04 March 2022
Key Points

  • P wave radial anisotropic structure beneath the young and highly extended Woodlark rift is constrained from teleseismic tomography

  • Downwelling of slab relics bordering the rift zone may contribute to ultra-high pressure rock exhumation and rift development

  • Slab-pull drives rift initiation and induces decompression melting in the upper mantle under the rift zone by horizontal stress transfer

Oceans

Open Access

Double Diffusion As a Driver of Turbulence in the Stratified Boundary Layer Beneath George VI Ice Shelf

  • First Published: 21 February 2022
Key Points

  • Year-long borehole mooring data in the George VI Ice Shelf ice-ocean boundary layer are analyzed

  • Observed dissipation rates do not vary with mean-flow speed suggesting turbulence is not shear-driven

  • Double-diffusive convection can explain the observed dissipation rates and melt rates, providing a route for parameterization

Free Access

Differentiating the Causes of Aged Organic Carbon in Marine Sediments

  • First Published: 28 February 2022
Key Points

  • A mathematical index is described to differentiate the causes of sedimentary aged OC

  • Lateral transport exerts a strong influence on the age spectrum of OC in marine sediments

  • Lateral transport and terrestrial inputs both contribute to old ages of OC in marine sediments

Hydrology and Land Surface Studies

Free Access

Process Controls on Flood Seasonality in Brazil

  • First Published: 28 February 2022
Key Points

  • Flood peaks tend to occur at the same time of year as annual soil moisture peaks and lag behind annual rainfall peaks by 3 weeks

  • Flood seasonality is linked mainly with soil moisture peaks in Amazonia and central Brazil, where soil storage capacity is high

  • Flood timing is highly correlated with rainfall and soil moisture peaks in the south and southeast, where soil storage capacity is low

Solid Earth

Free Access

A Unifying Model for Pyroclastic Surge Genesis and Pyroclastic Flow Fluidization

  • First Published: 15 February 2022
Key Points

  • We present a coherent model for the high-fluidity of small-volume pyroclastic flows and for the genesis of ash-cloud surges

  • Conclusions are drawn from field observations at Merapi volcano, laboratory experiments and numerical models

  • The movement of the rock fragments on the steepest slopes of the volcano both creates the pyroclastic surge and induces large runouts

Climate

Open Access

No Internal Connections Detected Between Low Frequency Climate Modes in North Atlantic and North Pacific Basins

  • First Published: 21 February 2022
Key Points

  • A multi model large ensemble archive and modified statistical assumptions provide a framework for studying climatic relationships

  • An analysis of relationships between leading Northern Hemisphere climate modes does not show any internal connections

  • External forcing such as global warming is shown to be a possible confounding factor in climate relationships

Research Article

Oceans

Free Access

Autonomous Wintertime Observations of Air-Sea Exchange in the Gulf Stream Reveal a Perfect Storm for Ocean CO2 Uptake

  • First Published: 07 February 2022
Key Points

  • Surface waters in the subtropical mode water formation region are lower in pCO2 than in the atmosphere in winter by ∼50 μatm

  • Strong wintertime winds drive atmospheric CO2 into the ocean near the Gulf Stream with high spatial and temporal variability

  • Uncrewed surface vehicles provide an opportunity to refine quantification and understanding of CO2 exchange near western boundary currents

Research Letter

Hydrology and Land Surface Studies

Free Access

Benthic Biolayer Structure Controls Whole-Stream Reactive Transport

  • First Published: 01 March 2022
Key Points

  • Storage in non-reactive sublayer causes long contaminant survival times

  • Reach-scale reaction kinetics cannot be captured by constant rate model

  • Upscaled model quantifies all aspects of reaction and mass transfer

Climate

Free Access

Enhanced Summer Convection Explains Observed Trends in Extreme Subdaily Precipitation in the Eastern Italian Alps

  • First Published: 02 March 2022
Key Points

  • We present a method for analyzing extreme precipitation trends based on the separation of storm intensity and occurrence frequency

  • Our approach reproduces observed trends in annual maxima and allows to quantify trends on rare return levels

  • Observed trends in the Eastern Italian Alps are explained by an increased proportion of heavy convective storms in the summer

Planets

Free Access

Cooling Crusts Create Concomitant Cryovolcanic Cracks

  • First Published: 21 February 2022
Key Points

  • Orbital eccentricity variations on 100 Myr timescales drive changes in ice shell thickness

  • Downward-propagating cracks can reach the subsurface ocean on Enceladus but do not reach Europa's ocean

  • On Enceladus, eruptions are likely sustained by decompression boiling

Climate

Open Access

Impacts of Precipitation Modeling on Cloud Feedback in MIROC6

  • First Published: 24 February 2022
Key Points

  • Acceleration of global warming by cloud altitude feedback is enhanced in MIROC6 when a prognostic precipitation scheme is introduced

  • Cloud altitude feedback is associated with high clouds in the present climate, which is better represented by prognostic precipitation

  • Cloud altitude feedback in CMIP models is suggested to increase when their underestimation of high-level clouds is mitigated

Space Sciences

Free Access

The First Observation of Additional Ionospheric Layers Over Arecibo Using an Incoherent Scatter Radar

  • First Published: 02 March 2022
Key Points

  • Events of an additional ionospheric (F3) layer are first reported at Arecibo

  • The formation of the F3 layers is mainly due to the gradient of the vertical ion drift

  • The height variation of the vertical ion drift is largely due to the zonal electric field

Climate

Free Access

Latitudinal Variation of the Lifetime Maximum Intensity Location of Atlantic Tropical Cyclones Controlled by the Atlantic Multidecadal Oscillation

  • First Published: 21 February 2022
Key Points

  • The negative correlation between the Atlantic multidecadal oscillation (AMO) and latitudinal variation of Atlantic tropical cyclone lifetime maximum intensity (LMI) is reaffirmed

  • Effects of variations in dominant track patterns and intra-pattern LMI location are almost equally important

  • Both variations of track patterns and intra-pattern LMI location are attributable to the AMO-related environments

Solid Earth

Free Access

Line-Source Model Based Rapid Inversion for Deriving Large Earthquake Rupture Characteristics Using High-Rate GNSS Observations

  • First Published: 28 February 2022
Key Points

  • We propose a new method for the rapid inversion of large earthquake rupture characteristics using high-rate Global Navigation Satellite System data

  • The fault rupture length, direction, and pattern (unilateral or bilateral) can be rapidly determined with considerable accuracy

  • The estimates of the rupture characteristics are expected to refine ground shaking predictions for large earthquakes (Mw > 6)

Atmospheric Science

Open Access

Satellite Observations of the Impact of Individual Aircraft on Ice Crystal Number in Thin Cirrus Clouds

  • First Published: 21 February 2022
Key Points

  • New satellite retrievals of ice crystal number concentration allow to assess microphysical effects of aviation on existing cirrus clouds

  • Comparison of ICNC profiles on existing cirrus clouds shows increase after aircraft by 25% and 54% ICNC

  • The signal is the largest 300–540 m below the flight altitude

Climate

Open Access

Southern China Winter Rainfall Modulated by South China Sea Warming

  • First Published: 03 March 2022
Key Points

  • Tropical air-sea interaction indices sometimes fail to identify strong southern China (SC) winter rainfall

  • The role of the South China Sea (SCS) in modulating SC winter rainfall under large-scale tropical air-sea interactions is revealed

  • A warmer SCS supports large nonlinear moisture transport from the SCS toward SC, resulting in strong SC winter rainfall

Atmospheric Science

Open Access

Large CO2 Emitters as Seen From Satellite: Comparison to a Gridded Global Emission Inventory

  • First Published: 28 February 2022
Key Points

  • We have retrieved some instantaneous CO2 emissions for one third of the large emission cells of a global high-resolution hourly inventory

  • The emission retrievals explain more than one third of the inventory variance at the corresponding cells and hours

  • Consistent temporal variations of median emissions suggest that trends can be robustly calculated when more data become available

Space Sciences

Open Access

First Observations of Large Scale Traveling Ionospheric Disturbances Using Automated Amateur Radio Receiving Networks

  • First Published: 21 February 2022
Key Points

  • Amateur radio data provides a new method for studying Large Scale Traveling Ionospheric Disturbances and HF communications impacts

  • Large Scale Traveling Ionospheric Disturbances are seen for the first time simultaneously in amateur radio, SuperDARN, and GNSS TEC data

  • Observed midlatitude Large Scale Traveling Ionospheric Disturbances are likely driven by auroral zone electrojet surges and Joule heating

Climate

Free Access

Concentrated and Intensifying Humid Heat Extremes in the IPCC AR6 Regions

  • First Published: 24 February 2022
Key Points

  • From 1979 to 2019, extreme wet-bulb temperatures intensified in most IPCC AR6 regions, though to varying degrees

  • Patterns in interannual clustering of extreme humid heat show signals of the overall warming trend and the El Niño-Southern Oscillation

  • In some arid regions, extreme humid heat days often occur in close temporal proximity to one another and to precipitation events

Atmospheric Science

Open Access

Streamer Discharges in the Atmosphere of Primordial Earth

  • First Published: 10 February 2022
Key Points

  • We perform simulations of electron avalanches and streamers in different gas mixtures for Primordial and Modern Earth

  • Ionization rates are higher in strongly reducing gas mixtures, such as used by Miller and Urey, than in weakly reducing mixtures

  • In the Miller and Urey gas mixture streamers incept at ≈114 Td; in weakly reducing atmospheres, suggested by Kasting, at 140–180 Td

Space Sciences

Free Access

Successive Dipolarization Fronts With a Stepwise Electron Acceleration During a Substorm in Saturn's Magnetotail

  • First Published: 01 March 2022
Key Points

  • Four successive dipolarization fronts (DFs) are identified in Saturn's magnetotail during one substorm

  • Three of the successive DFs cause a type of stepwise electron acceleration, generating energetic electrons

  • According to the electron pitch-angle distribution, the stepwise electron acceleration is identified as the Fermi acceleration mechanism

Climate

Open Access

Quantification of Seasonal and Interannual Variations of the Tibetan Plateau Surface Thermodynamic Forcing Based on the Potential Vorticity

  • First Published: 02 March 2022
Key Points

  • The Tibetan Plateau surface potential vorticity index (TP-SPVI) includes the effects from orographic thermal and dynamical forcing

  • The seasonal variation in the proposed TP-SPVI is consistent with the time evolution of the Asian summer monsoon precipitation

  • The surface PV can be used as a metric for the identification of the TP surface forcing in reanalysis data and for model evaluation

Cryosphere

Free Access

Positive Priming Effects Induced by Allochthonous and Autochthonous Organic Matter Input in the Lake Sediments With Different Salinity

  • First Published: 21 February 2022
Key Points

  • Allochthonous and autochthonous OM input can induce positive priming effect (PE) in saline lake sediments

  • Allochthonous OM input caused stronger PE intensity than autochthonous OM in saline lake sediments

  • Positive PE intensity increased with decreasing salinity of saline lakes

Solid Earth

Free Access

Constraints on Absolute Magma Chamber Volume From Geodetic Measurements of Trapdoor Faulting at Sierra Negra Volcano, Galapagos

  • First Published: 21 February 2022
Key Points

  • An upper bound on magma chamber volume is between 13.6 and 20.6 km3, depending on trapdoor fault dip (near-vertical faults favored)

  • The lower bound on volume is one-half the upper bound

  • These volume estimates are inversely proportional to the shear modulus (10 GPa here)

Free Access

Dynamic Rupture Modeling of Coseismic Interactions on Orthogonal Strike-Slip Faults

  • First Published: 15 February 2022
Key Points

  • Nucleation location effectively controls whether multifault rupture occurs on orthogonal strike-slip fault systems

  • A stopping phase from rupture reaching the end of one fault is often required to initiate rupture on the cross fault

  • Only a narrow range of regional stress orientations allows both cross-faults to rupture

Planets

Open Access

Silicate Volcanism on Europa's Seafloor and Implications for Habitability

  • First Published: 03 February 2022
Key Points

  • For volcanism to provide life-sustaining reactants to Europa's ocean, asthenospheric-formed melt must traverse the cold thick lithosphere

  • Dikes can propagate across the entire lithosphere if either the fracture toughness or the flux into the dike is large

  • Volcanism plausibly provides reactants to Europa's ocean every several thousand years, but seafloor volcanism is far from assured

Climate

Free Access

Termination 1 Millennial-Scale Rainfall Events Over the Sunda Shelf

  • First Published: 15 February 2022
Key Points

  • A new stalagmite record reveals for the first time distinct Bølling-Allerød and Younger Dryas oxygen isotope variations in northern Borneo

  • The stalagmite oxygen isotope pattern strongly resembles the recent iCESM transient annual rainfall simulation from 20 to 11 ka

  • Borneo drying during Heinrich 1 and the Younger Dryas may be attributed to an anomalous boreal winter Western North Pacific anticyclone

Solid Earth

Free Access

Orbital Forcing of Climatic Changes on the Central Tibetan Plateau Reveals Late Oligocene to Early Miocene South Asian Monsoon Evolution

  • First Published: 21 February 2022
Key Points

  • Paleoclimate evolution in the Lunpola Basin response to orbital forcing

  • The South Asian monsoon penetrated into central Tibet at least at ∼25.5 Ma

  • Low-magnetic units of the studied section mainly result from the reductive dissolution of hematite

Atmospheric Science

Free Access

Characteristics of Low-Frequency Pulses Associated With Downward Terrestrial Gamma-Ray Flashes

  • First Published: 28 February 2022
Key Points

  • Downward terrestrial gamma-ray flashes (TGFs) in winter thunderstorms of Japan can be classified into two types based on low-frequency (LF) observations

  • Three events were single-pulse TGFs coincident with high peak-current LF pulses of return strokes

  • Four events were followed by moderate peak-current LF pulses, and three of them are multi-pulse TGFs

Hydrology and Land Surface Studies

Open Access

Peatland Dissolved Organic Carbon Export to Surface Waters: Global Significance and Effects of Anthropogenic Disturbance

  • First Published: 28 February 2022
Key Points

  • Peatlands contribute 91 ± 54 Tg dissolved organic carbon (DOC) to surface waters and from 12% to 20% of the global organic carbon transferred to oceans

  • Air temperature explains the variability in DOC fluxes for undisturbed sites when it is discharge for disturbed sites

  • Major peatland areas are lacking from this synthesis, emphasizing the urgent need for fluvial carbon export evaluation from peatlands

Atmospheric Science

Open Access

Improving the Vertical Modeling of Tropospheric Delay

  • First Published: 02 March 2022
Key Points

  • New method for precise modeling of the zenith hydrostatic and wet delays from the Earth surface up to an altitude of 14 km

  • Tropospheric delay vertical modeling precision of better than 3 mm is achieved on a global scale

  • The method provides numerical weather model-derived precise tropospheric augmentation correction for real-time space geodetic techniques

Climate

Free Access

Impact of Climate Change on Hunter-Fisher-Gatherer Cultures in Northern Japan Over the Past 4,400 Years

  • First Published: 01 March 2022
Key Points

  • Cellulose oxygen isotope ratios of Sphagnum and vascular plants in peat cores were used to reveal the precipitated water oxygen isotopes

  • The results showed that the climate in northern Japan was governed by the position of westerlies and the Tsushima Warm Current strength

  • The climate changes affected the development of inland and marine cultures differently

Issue Information

Free Access

Issue Information

  • First Published: 24 February 2022