References of "Geophysical Research Letters"
     in
Bookmark and Share    
Peer Reviewed
See detailA 3400 year lacustrine paleoseismic record from the North Anatolian Fault, Turkey: Implications for bimodal recurrence behavior
Avsar, Ulas; Hubert, Aurelia ULg; De Batist, Marc et al

in Geophysical Research Letters (2014), 41(2), 377-384

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of ... [more ▼]

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of paleoearthquakes. A robust sediment chronology, spanning the last 3400 years, is constructed by radiocarbon dating and time-stratigraphical correlation with the precisely dated Sofular Cave speleothem record. Yeniçağa sedimentary sequence contains 11 seismically induced event deposits characterized by siliciclastic-enriched intervals. Some of the event deposits are also associated with implications of sudden lake deepening, which may be related to coseismic subsidence. The paleoearthquake series having an average recurrence interval of ca. 260 years are interrupted by two possible seismic gaps of ca. 420 and 540 years. [less ▲]

Detailed reference viewed: 37 (14 ULg)
Peer Reviewed
See detailA 3400 year lacustrine paleoseismic record from the North Anatolian Fault, Turkey: Implications for bimodal recurrence behavior
Avsar, Ulas; Hubert, Aurelia ULg; De Batist, Marc et al

in Geophysical Research Letters (2014), 41(2), 377-384

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of ... [more ▼]

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of paleoearthquakes. A robust sediment chronology, spanning the last 3400 years, is constructed by radiocarbon dating and time-stratigraphical correlation with the precisely dated Sofular Cave speleothem record. Yeniçağa sedimentary sequence contains 11 seismically induced event deposits characterized by siliciclastic-enriched intervals. Some of the event deposits are also associated with implications of sudden lake deepening, which may be related to coseismic subsidence. The paleoearthquake series having an average recurrence interval of ca. 260 years are interrupted by two possible seismic gaps of ca. 420 and 540 years. [less ▲]

Detailed reference viewed: 37 (14 ULg)
Full Text
Peer Reviewed
See detailCusp observation at Saturn’s high-latitude magnetosphere by the Cassini spacecraft
Jasinski; Arridge; Lamy et al

in Geophysical Research Letters (2014)

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailThe multiple spots of the Ganymede auroral footprint
Bonfond, Bertrand ULg; Hess, Sébastien; Bagenal, Fran et al

in Geophysical Research Letters (2013), 40

The interaction between the moons and the magnetosphere of giant planets sometimes gives rise to auroral signatures in the planetary ionosphere, called the satellite footprints. So far, footprints have ... [more ▼]

The interaction between the moons and the magnetosphere of giant planets sometimes gives rise to auroral signatures in the planetary ionosphere, called the satellite footprints. So far, footprints have been detected for Io, Europa, Ganymede, and Enceladus. These footprints are usually seen as single spots. However, the Io footprint, the brightest one, displays a much more complex morphology made of at least three different spots and an extended tail. Here we present Hubble Space Telescope FUV images showing evidence for a second spot in the Ganymede footprint. The spots separation distance changes as Ganymede moves latitudinally in the plasma sheet, as is seen for the Io footprint. This indicates that the processes identified at Io are universal. Moreover, for similar Ganymede System III longitudes, the distance may also vary significantly with time, indicating changes in the plasma sheet density. We identified a rapid evolution of this distance 8 days after the detection of a volcanic outburst at Io, suggesting that such auroral observations could be used to estimate the plasma density variations at Ganymede. [less ▲]

Detailed reference viewed: 46 (12 ULg)
Full Text
Peer Reviewed
See detailRapid loss of firn pore space accelerates 21st century Greenland mass loss
van Angelen, J.; Lenaerts, J.; van den Broeke, M. et al

in Geophysical Research Letters (2013), 40

Mass loss from the two major ice sheets and their contribution to global sea level rise is accelerating. In Antarctica, mass loss is dominated by increased flow velocities of outlet glaciers, following ... [more ▼]

Mass loss from the two major ice sheets and their contribution to global sea level rise is accelerating. In Antarctica, mass loss is dominated by increased flow velocities of outlet glaciers, following the thinning or disintegration of coastal ice shelves into which they flow. In contrast, ∼55% of post‒1992 Greenland ice sheet (GrIS) mass loss is accounted for by surface processes, notably increased meltwater runoff. A subtle process in the surface mass balance of the GrIS is the retention and refreezing of meltwater, currently preventing ∼40% of the meltwater to reach the ocean. Here we force a high‒resolution atmosphere/snow model with a mid‒range warming scenario (RCP4.5, 1970–2100), to show that rapid loss of firn pore space, by >50% at the end of the 21st century, quickly reduces this refreezing buffer. As a result, GrIS surface mass loss accelerates throughout the 21st century and its contribution to global sea level rise increases to 1.7 ±0.5 mm yr−1, more than four times the current value. [less ▲]

Detailed reference viewed: 20 (7 ULg)
Full Text
Peer Reviewed
See detailEvapotranspiration amplifies European summer drought
Teuling, Adriaan J.; Van Loon, Anne F.; Seneviratne, Sonia Isabelle et al

in Geophysical Research Letters (2013)

Drought is typically associated with a lack of precipitation, whereas the contribution of evapotranspiration and runoff to drought evolution is not well understood. Here, we use unique long-term ... [more ▼]

Drought is typically associated with a lack of precipitation, whereas the contribution of evapotranspiration and runoff to drought evolution is not well understood. Here, we use unique long-term observations made in four headwater catchments in Central and Western Europe to reconstruct storage anomalies and study the drivers of storage anomaly evolution during drought. We provide observational evidence for the ‘drought-paradox’ in that region: a consistent and significant increase in evapotranspiration during drought episodes which acts to amplify the storage anomalies. In contrast, decreases in runoff act to limit storage anomalies. Our findings stress the need for the correct representation of evapotranspiration and runoff processes in drought indices. [less ▲]

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailIo's volcanism controls Jupiter's radio emissions
Yoneda, Mizuki; Tsuchiya, F.; Misawa, H. et al

in Geophysical Research Letters (2013)

Jupiter's sodium nebula showed an enhancement in late May through beginning of June, 2007. This means Io's volcanic activity and the magnetosphere's plasma content increased during this period. On the ... [more ▼]

Jupiter's sodium nebula showed an enhancement in late May through beginning of June, 2007. This means Io's volcanic activity and the magnetosphere's plasma content increased during this period. On the other hand, Jupiter's radio emission called HOM became quiet after the sodium nebula enhancement. The HOM emission is considered to be related to activity of aurorae on Jupiter. These observation results therefore suggest that the increase in plasma supply from Io into Jupiter's magnetosphere weakens its field aligned current, which generates the radio emissions and aurorae on Jupiter. By comparing our observation results to recent model and observation results we add supporting evidence to the possibility that Io's volcanism controls Jupiter's magnetospheric activity. [less ▲]

Detailed reference viewed: 51 (9 ULg)
Full Text
Peer Reviewed
See detailAssessing the potential of calcium-based artificial ocean alkalinization to mitigate rising atmospheric CO2 and ocean acidification
Ilyina, Tatiana; Wolf-Gladrow, Dieter; Munhoven, Guy ULg et al

in Geophysical Research Letters (2013), 40(22), 5909-5914

Enhancement of ocean alkalinity using calcium compounds, e.g., lime has been proposed to mitigate further increase of atmospheric CO2 and ocean acidification due to anthropogenic CO2 emissions. Using a ... [more ▼]

Enhancement of ocean alkalinity using calcium compounds, e.g., lime has been proposed to mitigate further increase of atmospheric CO2 and ocean acidification due to anthropogenic CO2 emissions. Using a global model, we show that such alkalinization has the potential to preserve pH and the saturation state of carbonate minerals at close to today's values. Effects of alkalinization persist after termination: Atmospheric CO2 and pH do not return to unmitigated levels. Only scenarios in which large amounts of alkalinity (i.e., in a ratio of 2:1 with respect to emitted CO2) are added over large ocean areas can boost oceanic CO2 uptake sufficiently to avoid further ocean acidification on the global scale, thereby elevating some key biogeochemical parameters, e.g., pH significantly above preindustrial levels. Smaller-scale alkalinization could counteract ocean acidification on a subregional or even local scale, e.g., in upwelling systems. The decrease of atmospheric CO2 would then be a small side effect. [less ▲]

Detailed reference viewed: 33 (2 ULg)
Full Text
Peer Reviewed
See detailAuroral signatures of multiple magnetopause reconnection at Saturn
Radioti, Aikaterini ULg; Grodent, Denis ULg; Gérard, Jean-Claude ULg et al

in Geophysical Research Letters (2013)

Detailed reference viewed: 16 (5 ULg)
Full Text
Peer Reviewed
See detailBursty magnetic reconnection at Saturn's magnetosphere
Badman, S. V.; Masters, A.; Hasegawa, H. et al

in Geophysical Research Letters (2013)

Detailed reference viewed: 15 (3 ULg)
Full Text
Peer Reviewed
See detailMeasurement and modeling of ablation of the bottom of supraglacial lakes in western Greenland
Tedesco, Marco; Luthje, M.; Steffen, K. et al

in Geophysical Research Letters (2012), 39(L02502), 5

We report measurements of ablation rates of the bottom of two supraglacial lakes and of temperatures at different depths collected during the summers of 2010 and 2011 in west Greenland. To our knowledge ... [more ▼]

We report measurements of ablation rates of the bottom of two supraglacial lakes and of temperatures at different depths collected during the summers of 2010 and 2011 in west Greenland. To our knowledge, this is the first time that such data sets are reported and discussed in the literature. The measured ablation rates at the bottom of the two lakes are of the order of ∼6 cm/day, versus a rate of ∼2.5–3 cm/day in the case of bare ice of surrounding areas. Though our measurements suggest the presence of a vertical temperature gradient, it is not possible to draw final conclusions as the measured gradient is smaller than the accuracy of our temperature sensors. In-situ measurements are compared with the results of a thermodynamic model forced with the outputs of a regional climate model. In general, the model is able to satisfactorily reproduce the measured quantities with RMSE of the order of 3–4 cm for the ablation and ∼1.5°C in the case of water temperature. Our results confirm that the ablation at the bottom of supraglacial lakes plays an important role on the overall lake volume with the ablation in the case of ice covered by a lake being 110–135% of that over bare ice at nearby locations. Beside ice sheet hydrological implications, melting at the bottom of a supraglacial lake might affect estimates of lake volume from spaceborne visible and near-infrared measurements. [less ▲]

Detailed reference viewed: 13 (4 ULg)
Full Text
Peer Reviewed
See detailAuroral evidence of Io's control over the magnetosphere of Jupiter
Bonfond, Bertrand ULg; Grodent, Denis ULg; Gérard, Jean-Claude ULg et al

in Geophysical Research Letters (2012), 39

Contrary to the case of the Earth, the main auroral oval on Jupiter is related to the breakdown of plasma corotation in the middle magnetosphere. Even if the root causes for the main auroral emissions are ... [more ▼]

Contrary to the case of the Earth, the main auroral oval on Jupiter is related to the breakdown of plasma corotation in the middle magnetosphere. Even if the root causes for the main auroral emissions are Io's volcanism and Jupiter's fast rotation, changes in the aurora could be attributed either to these internal factors or to fluctuations of the solar wind. Here we show multiple lines of evidence from the aurora for a major internally-controlled magnetospheric reconfiguration that took place in Spring 2007. Hubble Space Telescope far-UV images show that the main oval continuously expanded over a few months, engulfing the Ganymede footprint on its way. Simultaneously, there was an increased occurrence rate of large equatorward isolated auroral features attributed to injection of depleted flux tubes. Furthermore, the unique disappearance of the Io footprint on 6 June appears to be related to the exceptional equatorward migration of such a feature. The contemporary observation of the spectacular Tvashtar volcanic plume by the New-Horizons probe as well as direct measurement of increased Io plasma torus emissions suggest that these dramatic changes were triggered by Io's volcanic activity. [less ▲]

Detailed reference viewed: 30 (15 ULg)
Full Text
Peer Reviewed
See detailMorphometric dating of the fluvial landscape response to a tectonic perturbation
Demoulin, Alain ULg

in Geophysical Research Letters (2012), 39

Despite constant progress in numerical and field studies of landscape evolution, time evolution is still poorly constrained in many uplifted areas where low denudation rates prevent the use of low ... [more ▼]

Despite constant progress in numerical and field studies of landscape evolution, time evolution is still poorly constrained in many uplifted areas where low denudation rates prevent the use of low temperature thermochronology, especially outside high relief mountainous areas. Here, I show that regional statistics of the landscape metric R involving hypsometric integrals at three nested levels of a catchment are able to isolate the time effect on landscape geometry during the latter’s transient response to a tectonic perturbation. Analysis of 210 catchments from 9 regions of known uplift age worldwide shows that the regionally characteristic, R-derived SR index is in inverse power law relation with the time elapsed since a base level lowering. Suggesting a response time of 5 My, this finding has important implications for quantifying the rate of landform evolution and determining whether a landscape has reached steady-state form. [less ▲]

Detailed reference viewed: 21 (4 ULg)
Full Text
Peer Reviewed
See detailSimultaneous Cassini VIMS and UVIS observations of Saturn's southern aurora: Comparing emissions from H, H2 and H3+ at a high spatial resolution
Melin, H.; Stallard, T.; Miller, S. et al

in Geophysical Research Letters (2011), 38

Here, for the first time, temporally coincident and spatially overlapping Cassini VIMS and UVIS observations of Saturn's southern aurora are presented. Ultraviolet auroral H and H[SUB]2[/SUB] emissions ... [more ▼]

Here, for the first time, temporally coincident and spatially overlapping Cassini VIMS and UVIS observations of Saturn's southern aurora are presented. Ultraviolet auroral H and H[SUB]2[/SUB] emissions from UVIS are compared to infrared H[SUB]3[/SUB][SUP]+[/SUP] emission from VIMS. The auroral emission is structured into three arcs - H, H[SUB]2[/SUB] and H[SUB]3[/SUB][SUP]+[/SUP] are morphologically identical in the bright main auroral oval (˜73°S), but there is an equatorward arc that is seen predominantly in H (˜70°S), and a poleward arc (˜74°S) that is seen mainly in H[SUB]2[/SUB] and H[SUB]3[/SUB][SUP]+[/SUP]. These observations indicate that, for the main auroral oval, UV emission is a good proxy for the infrared H[SUB]3[/SUB][SUP]+[/SUP] morphology (and vice versa), but for emission either poleward or equatorward this is no longer true. Hence, simultaneous UV/IR observations are crucial for completing the picture of how the atmosphere interacts with the magnetosphere. [less ▲]

Detailed reference viewed: 19 (4 ULg)
Full Text
Peer Reviewed
See detailQuasi-periodic polar flares at Jupiter: A signature of pulsed dayside reconnections?
Bonfond, Bertrand ULg; Vogt, M. F.; Gérard, Jean-Claude ULg et al

in Geophysical Research Letters (2011), 38

The most dynamic part of the Jovian UV aurora is located inside the main auroral oval. This region is known to regularly show localized but dramatic enhancements on timescales of several tens of seconds ... [more ▼]

The most dynamic part of the Jovian UV aurora is located inside the main auroral oval. This region is known to regularly show localized but dramatic enhancements on timescales of several tens of seconds, called polar flares. They have often been associated with the polar cusp, based on their location in the polar cap. The present study is based on the longest high-time resolution image sequences ever acquired by the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. We report the first observations of a regularity in the occurrence of these flares, with a timescale of 2-3 minutes. We use a magnetic flux mapping model to identify the region corresponding to these emissions in the equatorial plane: the radial distance ranges from 55 to 120 Jovian radii and the local times are between 10: 00 and 18: 00. The analogy with similar phenomena observed at Earth suggests that these quasi-periodic auroral flares could be related to pulsed reconnections at the dayside magnetopause. Indeed, the flares' projected location in the equatorial plane and their rate of re-occurrence show some similarities with the properties of the flux transfer events observed by the Pioneer and Voyager probes. [less ▲]

Detailed reference viewed: 27 (8 ULg)
Full Text
Peer Reviewed
See detailEnhanced ocean temperature forecast skills through 3-D super-ensemble multi-model fusion
Lenartz, Fabian ULg; Mourre, B.; Barth, Alexander ULg et al

in Geophysical Research Letters (2010), 37(L19606),

Detailed reference viewed: 32 (15 ULg)
Full Text
Peer Reviewed
See detailVenus OH nightglow distribution based on VIRTIS limb observations from Venus Express
Soret, Lauriane ULg; Gérard, Jean-Claude ULg; Piccioni, Giuseppe et al

in Geophysical Research Letters (2010), 37

The full set of VIRTIS‐M limb observations of the OH Venus nightglow has been analyzed to determine its characteristics. Based on 3328 limb profiles, we find that the mean peak intensity along the line of ... [more ▼]

The full set of VIRTIS‐M limb observations of the OH Venus nightglow has been analyzed to determine its characteristics. Based on 3328 limb profiles, we find that the mean peak intensity along the line of sight of the OH(deltaV = 1 sequence) is 0.35 MR and is located at 96.4 ± 5 km. The emission is highly variable and no dependence of the airglow layer altitude versus the antisolar angle is observed. The peak brightness appears to decrease away from the antisolar point even if the variability at a given location is very strong. Some correlation between the intensity of the OH and the O2(a1Delta) emissions is also observed, resumably because atomic oxygen is a common precursor to the formation of O2(a1Delta) and O3, whose reaction with H produces excited OH. Comparing our results with predictions from a photochemical model, a constant H flux does not match the simultaneous OH and O2 airglow observations. [less ▲]

Detailed reference viewed: 35 (13 ULg)
Full Text
Peer Reviewed
See detailVariation of Saturn's UV aurora with SKR phase
Nichols, J. D.; Cecconi, B.; Clarke, J. T. et al

in Geophysical Research Letters (2010), 37

It is well known that a wide range of kronian magnetospheric phenomena, including the Saturn kilometric radiation (SKR), exhibit oscillations near the planetary rotation period. However, although the SKR ... [more ▼]

It is well known that a wide range of kronian magnetospheric phenomena, including the Saturn kilometric radiation (SKR), exhibit oscillations near the planetary rotation period. However, although the SKR is believed to be generated by unstable auroral electrons, no connection has been established to date between diurnal SKR modulations and UV auroral power. We use an empirical SKR phase determined from Cassini observations to order the 'quiet time' total emitted UV auroral power as observed by the Hubble Space Telescope in programs during the interval 2005-2009. Our results indicate that both the northern and southern UV powers are dependent on SKR phase, varying diurnally by factors of similar to 3. We also show that the UV variation originates principally from the morning half of the oval, consistent with previous observations of the SKR sources. Citation: Nichols, J. D., B. Cecconi, J. T. Clarke, S. W. H. Cowley, J.-C. Gerard, A. Grocott, D. Grodent, L. Lamy, and P. Zarka (2010), Variation of Saturn's UV aurora with SKR phase, Geophys. Res. Lett., 37, L15102, doi: 10.1029/2010GL044057. [less ▲]

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailEvaluation of sinks and sources of CO2 in the global coastal ocean using a spatially-explicit typology of estuaries and continental shelves
Laruelle, Goulven G; Durr, Hans H; Slomp, Caroline P et al

in Geophysical Research Letters (2010), 37

The exchange of CO2 between the atmosphere and the global coastal ocean was evaluated from a compilation of air-water CO2 fluxes scaled using a spatially-explicit global typology of inner estuaries ... [more ▼]

The exchange of CO2 between the atmosphere and the global coastal ocean was evaluated from a compilation of air-water CO2 fluxes scaled using a spatially-explicit global typology of inner estuaries (excluding outer estuaries such as large river deltas) and continental shelves. The computed emission of CO2 to the atmosphere from estuaries (+0.27 +/- 0.23 PgC yr(-1)) is similar to 26% to similar to 55% lower than previous estimates while the sink of atmospheric CO2 over continental shelf seas (-0.21 +/- 0.36 PgC yr(-1)) is at the low end of the range of previous estimates (-0.22 to -1.00 PgC yr(-1)). The air-sea CO2 flux per surface area over continental shelf seas (-0.7 +/- 1.2 molC m(-2) yr(-1)) is the double of the value in the open ocean based on the most recent CO2 climatology. The largest uncertainty of scaling approaches remains in the availability of CO2 data to describe the spatial variability, and to capture relevant temporal scales of variability. Citation: Laruelle, G. G., H. H. Durr, C. P. Slomp, and A. V. Borges (2010), Evaluation of sinks and sources of CO2 in the global coastal ocean using a spatially-explicit typology of estuaries and continental shelves, Geophys. Res. Lett., 37, L15607, doi:10.1029/2010GL043691. [less ▲]

Detailed reference viewed: 117 (2 ULg)
Full Text
Peer Reviewed
See detailHolocene carbon cycle dynamics
Kleinen, Thomas; Brovkin, Victor; von Bloh, Werner et al

in Geophysical Research Letters (2010), 37

We are investigating the late Holocene rise in CO2 by performing four experiments with the climate-carbon-cycle model CLIMBER2-LPJ. Apart from the deep sea sediments, important carbon cycle processes ... [more ▼]

We are investigating the late Holocene rise in CO2 by performing four experiments with the climate-carbon-cycle model CLIMBER2-LPJ. Apart from the deep sea sediments, important carbon cycle processes considered are carbon uptake or release by the vegetation, carbon uptake by peatlands, and CO2 release due to shallow water sedimentation of CaCO3. Ice core data of atmospheric CO2 between 8 ka BP and preindustrial climate can only be reproduced if CO2 outgassing due to shallow water sedimentation of CaCO3 is considered. In this case the model displays an increase of nearly 20 ppmv CO2 between 8 ka BP and present day. Model configurations that do not contain this forcing show a slight decrease in atmospheric CO2. We can therefore explain the late Holocene rise in CO2 by invoking natural forcing factors only, and anthropogenic forcing is not required to understand preindustrial CO2 dynamics. [less ▲]

Detailed reference viewed: 10 (2 ULg)