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Author

Hideki Narita

Bio: Hideki Narita is an academic researcher from Hokkaido University. The author has contributed to research in topics: Ice core & Dome (geology). The author has an hindex of 18, co-authored 62 publications receiving 3161 citations. Previous affiliations of Hideki Narita include National Institute of Polar Research.
Topics: Ice core, Dome (geology), Snow, Ice stream, Firn


Papers
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Journal ArticleDOI
09 Sep 2004-Nature
TL;DR: An undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period, shows a slow decline in temperatures that marked the initiation of the last glacial period.
Abstract: High-resolution record of Northern Hemisphere climate extending into the last interglacial period

2,522 citations

Journal ArticleDOI
Hiroshi Fukazawa1, Ken Sugiyama1, Shinji Mae1, Hideki Narita1, Takeo Hondoh1 
TL;DR: In this article, the authors measured the Raman spectra of the junctions where three crystal grains met (triple-junctions) in polycrystalline ice from two Antarctic sites (Nansen ice and South Yamato ice) in order to obtain direct evidence that sulfuric and nitric acids are present as liquid at the triple junctions.
Abstract: We measured the Raman spectra of the junctions where three crystal grains met (triple-junctions) in polycrystalline ice from two Antarctic sites (Nansen ice and South Yamato ice) in order to obtain direct evidence that sulfuric and nitric acids are present as liquid at the triple-junctions. We found that Raman spectra of Nansen ice have a peak (1050 cm−1) of HSO4− and NO3− in sulfuric and nitric acid solutions when the measured temperatures of the ice are −8 ∼ −35°C. Thus, sulfuric and nitric acids dissociate to HSO4− and NO3− at the triple-junctions of Nansen ice. Raman spectra of South Yamato ice have a peak (980 cm−1) of SO42− in sulfuric acid solution when the measured temperatures of the ice are −8 ∼ −20°C. Thus, sulfuric acid dissociates to SO42− at the triple-junctions of South Yamato ice. The results showed that aqueous solutions of the acids exist at Antarctic ice-sheet temperatures.

105 citations

Journal ArticleDOI
TL;DR: In this paper, a 100m ice core from site G 15 (accumulation rate 0.1 m water yr−1, mean annual temperature −38°C) on the Mizuho plateau, Dronning Maud Land, East Antarctica, has been analyzed using the DE technique.
Abstract: A 100-m ice core from site G 15 (accumulation rate 0.1 m water yr−1, mean annual temperature −38°C) on the Mizuho plateau, Dronning Maud Land, East Antarctica, has been analysed using the dielectric profiling (DEP) technique. The capacitance and conductance of the core were measured at ac frequencies (20 Hz-300 kHz). The high-frequency conductivity profile shows variations that are primarily related to the strong acids derived from volcanic activity. The Tambora (1815) eruption can be identified with the aid of an approximate chronology based on the firn densification rate, other historic eruptions can then be recognised. Beyond about 300-years historical observations are very few, however if a constant overall accumulation rate is assumed, a well-known eruption of 1259 A.D. can be found near the bottom of the core. Other peaks in the conductivity profile can then be assigned dates accurate to within a few years. Using the conductivity profile it is possible to estimate the relative acid deposition fluxes produced by the main eruptions with reasonable accuracy. The estimated acid deposisition fluxes realtive to the Tambora (1815) eruption, of Agung (1963) is 27%, Krakatoa (1883), 25%, the signal of 1601, 28%, and that of 1259, 53%.

97 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive study of ice-crystal fabrics and textures was conducted on the Dome F (Antarctica) ice core and the results indicated that nucleation-recrystallization does not take place at Dome F. The general feature of textural and fabric development through a 2500 m long core was obtained by a 20 m interval study.
Abstract: A comprehensive study of ice-crystal fabrics and textures was conducted on the Dome F (Antarctica) ice core. Crystal ,-axis orientations, crystal sizes and crystal shape were measured on thin sections with an automatic ice-fabric analyzer. The general feature of textural and fabric development through a 2500 m long core was obtained by a 20 m interval study. Crystal size steadily increases with depth except for depths of about 500,1800, 2000, 2200 and 2300 m, at which depths crystal size decreases suddenly. There is a clear correlation between crystal-size and ´18O values. Crystals tend to elongate horizontally with depth, and the aspect ratio (long axis vs short axis of a grain) increases twofold at 1600 m depth and fluctuates below that depth. The .-axis orientation fabrics gradually change with depth from a random orientation pattern near the surface to a strong vertical single maximum at 2500 m. These are very similar to those from the GRIP (Greenland) core The observations of crystal shape and the fabric measurements indicate that nucleation-recrystallization does not take place at Dome F.

58 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the total friction coefficient of two hard sintered snow plates, ranging roughly from 0.2 to 0.8, which were separated into velocityindependent dry friction and linearly dependent viscous friction; only at velocities larger than 15 m/s did friction increase parabolically, evidence of turbulent friction.
Abstract: Snow and ice friction was investigated with a shear cell in which two surfaces of annular snow and/or ice samples were in contact and sheared by rotation. The temperature ranged from 0 to −25 °C, normal stress from 205 to 1292 Pa, and velocity from 0.9 to 25.3 m/s. The total friction coefficients measured by friction of two hard sintered snow plates ranged roughly from 0.2 to 0.8, which were separated into velocity‐independent dry friction and linearly dependent viscous friction; only at velocities larger than 15 m/s did friction increase parabolically, evidence of turbulent friction. The dry friction coefficient (μD) was found to consist of Coulomb friction and adhesion, both of which were strongly dependent on temperature and hardness of snow; μD decreased linearly with lowering temperature from 0.47 at 0 °C to 0.22 at −25 °C. Viscosity was found to be dependent on snow type (grain characteristics) but independent of temperature; the average kinematic viscosity was roughly 5×10−5 m2/s for snow of density around 350 kg/m3. The total friction coefficient for ice‐ice friction was an order of magnitude smaller than that of snow‐snow friction, typically less than 0.04; its magnitude increased with velocity but at lower temperatures (e.g., −35 °C) it decreased exponentially with velocity. The minimum Coulomb friction coefficient as small as 0.008 was observed at −11 °C. All the friction coefficients for snow‐snow, snow‐ice, and ice‐ice friction were summarized in temperature‐velocity diagrams, which conveniently show the overall behaviors of snow and ice friction.

54 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP.
Abstract: Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.

2,800 citations

Journal ArticleDOI
06 May 2005-Science
TL;DR: A 5-year-resolution absolute-dated oxygen isotope record from Dongge Cave, southern China, provides a continuous history of the Asian monsoon over the past 9000 years, and shows that some, but not all, of the monsoon variability at these frequencies results from changes in solar output.
Abstract: A 5-year-resolution absolute-dated oxygen isotope record from Dongge Cave, southern China, provides a continuous history of the Asian monsoon over the past 9000 years. Although the record broadly follows summer insolation, it is punctuated by eight weak monsoon events lasting approximately 1 to 5 centuries. One correlates with the "8200-year" event, another with the collapse of the Chinese Neolithic culture, and most with North Atlantic ice-rafting events. Cross-correlation of the decadal- to centennial-scale monsoon record with the atmospheric carbon-14 record shows that some, but not all, of the monsoon variability at these frequencies results from changes in solar output.

2,139 citations

Journal ArticleDOI
15 May 2008-Nature
TL;DR: It is found that atmospheric carbon dioxide is strongly correlated with Antarctic temperature throughout eight glacial cycles but with significantly lower concentrations between 650,000 and 750,000 yr before present, which extends the pre-industrial range of carbon dioxide concentrations during the late Quaternary by about 10 p.p.m.v.
Abstract: Changes in past atmospheric carbon dioxide concentrations can be determined by measuring the composition of air trapped in ice cores from Antarctica. So far, the Antarctic Vostok and EPICA Dome C ice cores have provided a composite record of atmospheric carbon dioxide levels over the past 650,000 years. Here we present results of the lowest 200 m of the Dome C ice core, extending the record of atmospheric carbon dioxide concentration by two complete glacial cycles to 800,000 yr before present. From previously published data and the present work, we find that atmospheric carbon dioxide is strongly correlated with Antarctic temperature throughout eight glacial cycles but with significantly lower concentrations between 650,000 and 750,000 yr before present. Carbon dioxide levels are below 180 parts per million by volume (p.p.m.v.) for a period of 3,000 yr during Marine Isotope Stage 16, possibly reflecting more pronounced oceanic carbon storage. We report the lowest carbon dioxide concentration measured in an ice core, which extends the pre-industrial range of carbon dioxide concentrations during the late Quaternary by about 10 p.p.m.v. to 172-300 p.p.m.v.

1,977 citations

Journal ArticleDOI
TL;DR: In this paper, a new common stratigraphic timescale for the North Greenland Ice Core Project (NGRIP) and GRIP ice cores is presented, which covers the period 7.9-14.8 kyr before present and includes the Bolling, Allerod, Younger Dryas, and early Holocene periods.
Abstract: [1] We present a new common stratigraphic timescale for the North Greenland Ice Core Project (NGRIP) and GRIP ice cores. The timescale covers the period 7.9–14.8 kyr before present and includes the Bolling, Allerod, Younger Dryas, and early Holocene periods. We use a combination of new and previously published data, the most prominent being new high-resolution Continuous Flow Analysis (CFA) impurity records from the NGRIP ice core. Several investigators have identified and counted annual layers using a multiparameter approach, and the maximum counting error is estimated to be up to 2% in the Holocene part and about 3% for the older parts. These counting error estimates reflect the number of annual layers that were hard to interpret, but not a possible bias in the set of rules used for annual layer identification. As the GRIP and NGRIP ice cores are not optimal for annual layer counting in the middle and late Holocene, the timescale is tied to a prominent volcanic event inside the 8.2 kyr cold event, recently dated in the DYE-3 ice core to 8236 years before A. D. 2000 (b2k) with a maximum counting error of 47 years. The new timescale dates the Younger Dryas-Preboreal transition to 11,703 b2k, which is 100–150 years older than according to the present GRIP and NGRIP timescales. The age of the transition matches the GISP2 timescale within a few years, but viewed over the entire 7.9–14.8 kyr section, there are significant differences between the new timescale and the GISP2 timescale. The transition from the glacial into the Bolling interstadial is dated to 14,692 b2k. The presented timescale is a part of a new Greenland ice core chronology common to the DYE-3, GRIP, and NGRIP ice cores, named the Greenland Ice Core Chronology 2005 (GICC05). The annual layer thicknesses are observed to be log-normally distributed with good approximation, and compared to the early Holocene, the mean accumulation rates in the Younger Dryas and Bolling periods are found to be 47 ± 2% and 88 ± 2%, respectively.

1,789 citations

Journal ArticleDOI
10 Aug 2007-Science
TL;DR: It is suggested that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records.
Abstract: A high-resolution deuterium profile is now available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage 20.2, ∼800,000 years ago. Experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation. We assessed the general correspondence between Dansgaard-Oeschger events and their smoothed Antarctic counterparts for this Dome C record, which reveals the presence of such features with similar amplitudes during previous glacial periods. We suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records.

1,723 citations