pinecone/core-2020-05-10-deduplication huggingface dataset:
Correction to “Changes in Arctic sea ice result in increasing light transmittance and absorption”

In the paper “Changes in Arctic sea ice result in increasing light transmittance and absorption” by Nicolaus\ud
et al. (Geophysical Research Letters, 39(24), L24501, doi:10.1029/2012GL053738, 2012), the presented data on\ud
solar surface irradiance are erroneous. In order to generate monthly means of the solar heat input into the Arctic Ocean, among others, the ERA interim (European Centre for Medium-Range Weather Forecasts) data set of solar surface irradiance was used. The original data set consists of eight time slices with integrated fluxes over 3 h each. But in the presented results, only the mean (not sum) of two slices (from 00:00 to 03:00 and from 12:00 to 15:00) was considered, resulting in too low fluxes, approx. by a factor of eight. As a consequence, two text passages (in paragraph 3.1 and 3.3) and three figures (Figure 4 of the main article and\ud
Figures S3 and S6 of the auxiliary material) contain too low fluxes. However, the main conclusions of the manuscript remain completely valid and unchanged, since those are only based on relative fluxes, which are not affected by this mistake
Remotely induced warming of Antarctic Bottom Water in the eastern Weddell gyre

Four repeat hydrographic sections across the eastern Weddell gyre at 30°E reveal a warming (by ~0.1°C) and lightening (by ~0.02–0.03 kg m−3) of the Antarctic Bottom Water (AABW) entering the gyre from the Indian sector of the Southern Ocean between the mid-1990s and late 2000s. Historical hydrographic and altimetric measurements in the region suggest that the most likely explanation for the change is increased entrainment of warmer mid-depth Circumpolar Deep Water by cascading shelf water plumes close to Cape Darnley, where the Indian-sourced AABW entering the Weddell gyre from the east is ventilated. This change in entrainment is associated with a concurrent southward shift of the Antarctic Circumpolar Current's (ACC) southern boundary in the region. This mechanism of AABW warming may affect wherever the ACC flows close to Antarctica
Overturning circulation driven by breaking internal waves\ud
in the deep ocean

A global estimate of the water-mass transformation by\ud
internal wave-driven mixing in the deep ocean is presented.\ud
The estimate is based on the energy conversion from tidal\ud
and geostrophic motions into internal waves combined with\ud
a turbulent mixing parameterization. We show that internal\ud
wave-driven mixing in the deep ocean can sustain 20–30 Sv\ud
of water-mass transformation. One third or more of\ud
this transformation is attributed to lee waves generated\ud
by geostrophic motions flowing over rough topography,\ud
primarily in the Southern Ocean. While these results are\ud
uncertain due to many assumptions, poorly constrained\ud
parameters and data noise that enter in the calculation, the\ud
result that lee wave-driven mixing plays an important role\ud
in the abyssal ocean circulation is likely robust. The\ud
implication is that lee wave-driven mixing should be\ud
represented in ocean and climate models, but currently\ud
it is not. Citation: Nikurashin, M., and R. Ferrari (2013),\ud
Overturning circulation driven by breaking internal waves in the\ud
deep ocean, Geophys. Res. Lett., 40, doi:10.1002/grl.50542
Limb imaging of the Venus O2 visible nightglow with the Venus Monitoring
  Camera

We investigated the Venus O2 visible nightglow with imagery from the Venus
Monitoring Camera on Venus Express. Drawing from data collected between April
2007 and January 2011, we study the global distribution of this emission,
discovered in the late 70s by the Venera 9 and 10 missions. The inferred
limb-viewing intensities are on the order of 150 kiloRayleighs at the lower
latitudes and seem to drop somewhat towards the poles. The emission is
generally stable, although there are episodes when the intensities rise up to
500 kR. We compare a set of Venus Monitoring Camera observations with
coincident measurements of the O2 nightglow at 1.27 {\mu}m made with the
Visible and Infrared Thermal Imaging Spectrometer, also on Venus Express. From
the evidence gathered in this and past works, we suggest a direct correlation
between the instantaneous emissions from the two O2 nightglow systems. Possible
implications regarding the uncertain origin of the atomic oxygen green line at
557.7 nm are noted.Comment: 7 pages, 3 figure
Interacting length scales in the reactive-infiltration instability

The reactive-infiltration instability, which develops when a porous matrix is
dissolved by a flowing fluid, contains two important length scales. Here we
outline a linear stability analysis that simultaneously incorporates both
scales. We show that the commonly used "thin-front" model is a limiting case of
a more general theory, which also includes convection-dominated dissolution as
another special case. The wavelength of the instability is bounded from below,
and lies in the range 1mm to 1km for physically reasonable flow rates and
reaction rates. We obtain a closed form for the growth rate when the change in
porosity is small.Comment: to be published. in Geophys. Res. Let
THEMIS Observations of the Magnetopause Electron Diffusion Region: Large
  Amplitude Waves and Heated Electrons

We present the first observations of large amplitude waves in a well-defined
electron diffusion region at the sub-solar magnetopause using data from one
THEMIS satellite. These waves identified as whistler mode waves, electrostatic
solitary waves, lower hybrid waves and electrostatic electron cyclotron waves,
are observed in the same 12-sec waveform capture and in association with
signatures of active magnetic reconnection. The large amplitude waves in the
electron diffusion region are coincident with abrupt increases in electron
parallel temperature suggesting strong wave heating. The whistler mode waves
which are at the electron scale and enable us to probe electron dynamics in the
diffusion region were analyzed in detail. The energetic electrons (~30 keV)
within the electron diffusion region have anisotropic distributions with
T_{e\perp}/T_{e\parallel}>1 that may provide the free energy for the whistler
mode waves. The energetic anisotropic electrons may be produced during the
reconnection process. The whistler mode waves propagate away from the center of
the 'X-line' along magnetic field lines, suggesting that the electron diffusion
region is a possible source region of the whistler mode waves
Is land subsidence increasing the exposure to sea level rise in Alexandria, Egypt?

International audienceDelta margins are subject to relatively high rates of land subsidence and have the potential to significantly exacerbate future changes in sea levels predicted by global warming models used in impact studies. Through a combined analysis of GPS and persistent scatterer interferometry data, we determine that most of the coastline of Alexandria has been subject to moderate land subsidence over the past decade (0.4 mm/year on average and up to 2 mm/year locally). This contrasts to previous studies that suggested subsidence in excess of 3 mm/year. Based on our findings, we infer that on multi-century to millennia timescales, land subsidence in the area of Alexandria is dominated by tectonic setting and earthquakes or gravitational collapse episodes of a growth fault, whereas on shorter inter-seismic decadal to century timescales, subsidence rates are likely steady and moderate, in agreement with natural compaction and dewatering of the observed Holocene sediment layer
Extreme densities in Titan's ionosphere during the T85 magnetosheath encounter

We present Cassini Langmuir probe measurements of the highest electron number densities ever reported from the ionosphere of Titan. The measured density reached 4310 cm−3 during the T85 Titan flyby. This is at least 500 cm−3 higher than ever observed before and at least 50% above the average density for similar solar zenith angles. The peak of the ionospheric density is not reached on this flyby, making the maximum measured density a lower limit. During this flyby, we also report that an impacting coronal mass ejection (CME) leaves Titan in the magnetosheath of Saturn, where it is exposed to shocked solar wind plasma for at least 2 h 45 min. We suggest that the solar wind plasma in the magnetosheath during the CME conditions significantly modifies Titan's ionosphere by an addition of particle impact ionization by precipitating protons.Fil: Edberg, N. J. T.. Swedish Institute of Space Physics; SueciaFil: Andrews, D. J.. Swedish Institute of Space Physics; SueciaFil: Shebanits, O.. Swedish Institute of Space Physics; SueciaFil: Agren, K.. Swedish Institute of Space Physics; SueciaFil: Wahlund, J. E.. Swedish Institute of Space Physics; SueciaFil: Opgenoorth, H. J.. Swedish Institute of Space Physics; SueciaFil: Roussos, E.. Max Planck Institute for Solar System Research; AlemaniaFil: Garnier, P.. University of Toulouse; FranciaFil: Cravens, T.  E.. University of Kansas; Estados UnidosFil: Badman, S. V.. University of Leicester; Reino UnidoFil: Modolo, R.. UVSQ/LATMOS-IPSL/CNRS-INSU; FranciaFil: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Dougherty, M. K.. Imperial College London; Reino Unid
Global statistical evidence for chorus as the embryonic source of plasmaspheric hiss

The origin of plasmaspheric hiss, the electromagnetic emission responsible for the gap between the inner and outer radiation belts, has been debated for over four decades. Recently, a new theory proposed that chorus, which is excited in the equatorial region outside the plasmapause, can propagate to low altitudes on the dayside and evolve into plasmaspheric hiss. Here we combine data from six satellites and show that chorus extends along the Earth's magnetic field to high latitudes in the prenoon sector, and, in the equatorial region, there is a clear gap of the order of 1–2 Earth radii between plasmaspheric hiss at L∗<4 and chorus further out, consistent with ray tracing modeling from a chorus source. Our observations confirm two of the key predictions of the new theory and provide the first statistical evidence for chorus as the embryonic source of plasmaspheric hiss
Recurrence Statistics of Great Earthquakes

We investigate the sequence of great earthquakes over the past century. To
examine whether the earthquake record includes temporal clustering, we identify
aftershocks and remove those from the record. We focus on the recurrence time,
defined as the time between two consecutive earthquakes. We study the variance
in the recurrence time and the maximal recurrence time. Using these quantities,
we compare the earthquake record with sequences of random events, generated by
numerical simulations, while systematically varying the minimal earthquake
magnitude Mmin. Our analysis shows that the earthquake record is consistent
with a random process for magnitude thresholds 7.0<=Mmin<=8.3, where the number
of events is larger. Interestingly, the earthquake record deviates from a
random process at magnitude threshold 8.4<=Mmin<= 8.5, where the number of
events is smaller; however, this deviation is not strong enough to conclude
that great earthquakes are clustered. Overall, the findings are robust both
qualitatively and quantitatively as statistics of extreme values and moment
analysis yield remarkably similar results.Comment: 5 pages, 6 figure
Polar cap patch segmentation of the tongue of ionization in the morning convection cell

Two types of poleward moving plasma concentration\ud
enhancements (PMPCEs) were observed during a sequence\ud
of pulsed reconnection events, both in the morning\ud
convection cell: Type L (low density) was associated with a\ud
cusp ﬂow channel and seems likely to have been produced\ud
by ionization associated with particle precipitation, while\ud
Type H (high density) appeared to originate from the\ud
segmentation of the tongue of ionization by the processes\ud
which produced the Type L events. As a result, the Type L\ud
and Type H PMPCEs were interspersed, producing a\ud
complex density structure which underlines the importance\ud
of cusp ﬂow channels as a mechanism for segmenting and\ud
structuring electron density in the cusp and shows the\ud
necessity of differentiating between at least two classes of\ud
electron density patches.STFC grant ST/H002480/1Peer-reviewedPublisher Versio
Intrusive dike complexes, cumulate cores, and the extrusive growth of Hawaiian volcanoes

The Hawaiian Islands are the most geologically studied hot-spot islands in the world yet surprisingly, the only large-scale compilation of marine and land gravity data is more than 45 years old. Early surveys served as reconnaissance studies only, and detailed analyses of the crustal-density structure have been limited. Here we present a new chain-wide gravity compilation that incorporates historical island surveys, recently published work on the islands of Hawai‘i, Kaua‘i, and Ni‘ihau, and >122,000 km of newly compiled marine gravity data. Positive residual gravity anomalies reflect dense intrusive bodies, allowing us to locate current and former volcanic centers, major rift zones, and a previously suggested volcano on Ka‘ena Ridge. By inverting the residual gravity data, we generate a 3-D view of the dense, intrusive complexes and olivine-rich cumulate cores within individual volcanoes and rift zones. We find that the Hāna and Ka‘ena ridges are underlain by particularly high-density intrusive material (>2.85 g/cm3) not observed beneath other Hawaiian rift zones. Contrary to previous estimates, volcanoes along the chain are shown to be composed of a small proportion of intrusive material (<30% by volume), implying that the islands are predominately built extrusively
Identification of a widespread Kamchatkan tephra: A middle Pleistocene tie-point between Arctic and Pacific paleoclimatic records

Very few age controls exist for Quaternary deposits over the vast territory of the East Russian Arctic, which hampers dating of major environmental changes in this area and prevents their correlation to climatic changes in the Arctic and Pacific marine domains. We report a newly identified ~177 ka old Rauchua tephra, which has been dispersed over an area of >1,500,000 km2 and directly links terrestrial paleoenvironmental archives from Arctic Siberia with marine cores in the northwest Pacific, thus permitting their synchronization and dating. The Rauchua tephra can help to identify deposits formed in terrestrial and marine environments during the oxygen isotope stage 6.5 warming event. Chemical composition of volcanic glass from the Rauchua tephra points to its island-arc origin, while its spatial distribution singles out the Kamchatka volcanic arc as a source. The Rauchua tephra represents a previously unknown, large (magnitude >6.5) explosive eruption from the Kamchatka volcanic arc
A model for the viscous dissipation rate in stably stratified, sheared turbulence

[1] A model for the turbulence dissipation rate in stably stratified shear turbulence is developed and validated. The functional dependence of the model is derived from first principles and it represents a conceptually new approach in that it depends on the background temperature field rather than on the fluctuating velocity field. This novel feature makes the proposed model a viable candidate for dissipation rate estimates in measured real-life flows. Direct numerical simulation data are used for a priori assessment of the proposed model. It is demonstrated that the proposed model performs very well, particularly in cases where the background stratification becomes dynamically important. Also, a generalized expression for the mixing coefficient has been rigorously derived from first principles assuming local isotropy of incompressible turbulent flows. The mixing coefficient is shown to depend on the Prandtl number and values are in correspondence with previous studies
On the detectability of internal waves by an imaging lidar

The first results of a multisensor airborne survey conducted off the western Iberian Coast are presented (including visible, lidar, and infrared imagery) and reveal the presence of internal solitary waves (ISWs) propagating into the nearshore region. For the first time, two-dimensional lidar imagery is shown to detect the presence of ISWs, and the results are interpreted in a more comprehensive framework provided by the remaining instrumentation. Sea surface roughness patterns, resulting from the ISWs, are found to be imaged in the lidar data, where specular reflection causes slicks to appear as areas of significantly reduced backscatter. Moreover, the lidar data reveal an unprecedented view into the ISW surface and subsurface structures. Possible interpretations are discussed based on the accumulation of surfactants and air bubble entrainment at the leading edge of the ISWs (where maximum convergence occurs)
Three-dimensional mapping by Cryosat 2 of subglacial lake volumes

We analyze data acquired by the CryoSat-2 interferometric radar altimeter and demonstrate its novel capability to track topographic features on the Antarctic Ice Sheet. We map the perimeter and depth of a 260 km2 surface depression above an Antarctic subglacial lake (SGL) and, in combination with Ice, Cloud and land Elevation Satellite laser altimetry, chart decadal changes in SGL volume. During 2007–2008, between 4.9 and 6.4 km3 of water drained from the SGL, and peak discharge exceeded 160 m3 s−1. The flood was twice as large as any previously recorded and equivalent to ~ 10% of the meltwater generated annually beneath the ice sheet. The ice surface has since uplifted at a rate of 5.6 ± 2.8 m yr−1. Our study demonstrates the ability of CryoSat-2 to provide detailed maps of ice sheet topography, its potential to accurately measure SGL drainage events, and the contribution it can make to understanding water flow beneath Antarctica
New data from borehole strainmeters to infer lava fountain sources (Etna 2011-2012)

In January 2011 eruptive activity resumed at Etna producing a new phase  with frequent lava fountain episodes until April 2012. In November 2011, the first two borehole strainmeters were installed, which  detected negative strain changes (~ 0.15 - 0.8 strain) during the paroxysmal events. A Finite Element Model was set up to estimate accurately the tilt and volumetric strain, taking into account the real profile of the volcano and the elastic medium heterogeneity. The numerical computations indicated an elongated depressurizing source located at 0 km b.s.l., which underwent a volume change of ~2 x 106 m3 which  is the most of the magma volume erupted while a smaller remaining part is  accommodated by the magma compressibility. This shallow source cannot accumulate large magma volumes and, thus, favours short term periodic eruptive events with a fairly constant balance between the refilling and the erupted magma
Decimeter-scale in situ mapping of modern cross-bedded dune deposits using parametric echo sounding : a new method for linking river processes and their deposits

Collecting high-resolution data to quantify the  sedimentary architecture within contemporary alluvial  channels remains one of the outstanding challenges in fluvial  sedimentology. Here, we present data collected using a new  geophysical method, the parametric echo sounder (PES),  which can meet this challenge. From surveys over a field of  sand dunes in the Río Paraná, Argentina, we demonstrate the  unique ability of PES to image the subsurface structure  within active channels at a decimetric resolution. These data  reveal the bounding surfaces between bars and dunes, as  well as the foresets and reactivation surfaces within them.  This provides quantitative in situ data for recent work that  suggests cross-strata preserved by dunes may be more  related to flow depths less than the commonly assumed  bankfull level. These surveys demonstrate that PES can  provide hitherto unobtainable data from alluvial channels  and presents significant opportunities for more detailed  coupled studies of fluvial processes and their depositsFil: Sambrook Smith, Gregory H.. University of Birmingham; Reino Unido;Fil: Best, James L.. University Of Illinois. Urbana - Champaign; Estados Unidos de América;Fil: Orfeo, Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Centro de Ecologia Aplicada del Litoral (i); Argentina;Fil: Vardy, Mark E.. University Of Illinois. Urbana - Champaign; Estados Unidos de América;Fil: Zinger, Jessica A.. University Of Illinois. Urbana - Champaign; Estados Unidos de América
Relative changes in CO emissions over megacities based on observations from space

International audienceUrban areas are large sources of several air pollutants with carbon monoxide (CO) among the largest. Yet measurement from space of their CO emissions remains elusive due to its long lifetime. Here we introduce a new method of estimating relative changes in CO emissions over megacities. A new multi-channel Measurements of Pollution in the Troposphere (MOPITT) CO data product, offering improved sensitivity to the boundary later, is used, to estimate this relative change over eight megacities: Moscow, Paris, Mexico, Tehran, Baghdad, Los Angeles, Sao Paulo and Delhi. By combining MOPITT observations with wind information from a meteorological reanalysis, changes in the CO upwind-downwind difference are used as a proxy for changes in emissions. Most locations show a clear reduction of CO emission between 2000-2003 and 2004-2008, reaching -43% over Tehran and -47% over Baghdad. There is contrasted agreement between these results and the MACcity and EDGARv4.2 inventories
Local late Amazonian boulder breakdown and denudation rate on Mars.

Inactive fan surfaces become smoother and develop desert pavement over time by weathering and erosion. We use this mechanism to estimate late Amazonian boulder breakdown and surface  denudation rates on a young (1.25 Ma) (Schon et al., 2009) fan on Mars. This is done by comparing boulder size and surface relief between lobes of different ages. The boulder breakdown rate is 3.5 m/Myr, surface smoothing (denudation) rate is approximated as\ud
0.89 m/Myr. These rates exceed previous estimates for the Amazonian by orders of magnitude. We attribute this to locality, high initial smoothing rates after morphological activity and obliquity and eccentricity-driven variation in the availability of (metastable) liquid water, which acts as a catalyst for weathering during these periods. The results have major implications for process interpretation of Martian landforms, as they imply that typical small-scale morphology may be subdued within <1 Myr
Quantifying recent acceleration in sea level unrelated to internal climate variability

Sea level observations suggest that the rate of sea level rise has accelerated during the last 20 years. However, the presence of considerable decadal-scale variability, especially on a regional scale, makes it difficult to assess whether the observed changes are due to natural or anthropogenic causes. Here we use a regression model with atmospheric pressure, wind, and climate indices as independent variables to quantify the contribution of internal climate variability to the sea level at nine tide gauges from around the world for the period 1920–2011. Removing this contribution reveals a statistically significant acceleration (0.022 ± 0.015 mm/yr2) between 1952 and 2011, which is unique over the whole period. Furthermore, we have found that the acceleration is increasing over time. This acceleration appears to be the result of increasing greenhouse gas concentrations, along with changes in volcanic forcing and tropospheric aerosol loading