Mineral and Sea-Salt Aerosol Fluxes over the Last 340 kyr Reconstructed from the Total Concentration of Al and Na in the Dome Fuji Ice Core

A quantitative analysis of the total concentrations of Al and Na in the Antarctic ice sheet during the past 340 kyr was performed by applying the acid digestion method to the Dome Fuji ice core. Atmospheric fluxes of mineral and sea-salt aerosol to Dome Fuji were calculated from the total concentration. The average fluxes of mineral aerosol to Dome Fuji in the periods of glacial maximum, 18.6 ± 10.1 mg·m–2·yr–1, were larger than the value in the interglacial periods, 3.77 ± 2.20 mg·m–2·yr–1. Conversely, the fluxes of sea-salt have no significant difference between the average value of glacial maximum, 130 ± 55 mg·m–2·yr–1, and that of interglacial, 111 ± 54 mg·m–2·yr–1. The results obtained in this study suggest that the variation of mineral aerosol flux in Dome Fuji, together with climate change, was much larger than that of sea-salt aerosol flux. This result may have occurred because the variety in the intensity of the source and transport during the glacial-interglacial cycle is more significant for mineral aerosol than that for sea-salt aerosol.

Variations of Atmospheric Carbon Dioxide Concentration and Greenhouse Effect at Syowa Station (69°00'S, 39°35'E), Antarctica

On the basis of the analysis of atmospheric carbon dioxide concentration variations and the annual mean air temperature at Syowa Station, Antarctica in the period of 1984-1988, the following results are easily obtained:(1) The annual mean values of the atmospheric carbon dioxide concentration are gradually increased and equal to 342.59, 343.80, 345.15, 346.83 and 348.82 ppmv for 1984, 1985, 1986, 1987 and 1988, respectively. Its annual increase rates are 1.21, 1.35, 1.68 and 1.99 ppmv/yr. For 1984-1985, 1985-1986, 1986-1987 and 1987-1988, respectively and are raised year by year.The seasonal variations are observed and the maximum concentration is in spring and the minimum one is in late-summer or early-autumn.(2)The increasing tendency of the concentration of the atmospheric carbon dioxide is consistent with that of the a.ir temperature.

Shallow Reflection Surveys of the East Ongul Island, the Lützow-Holm Complex, East Antarctica

The shallow reflection surveys were carried out in 2007 and 2010 austral summers in East Ongul Island, the Lützow-Holm Complex (LHC), East Antarctica. LHC is identified by geologically as one of the Pan-African terrains of Eastern Dronning Maud Land. The multi-channel reflection surveys targeted to achieve the image of laminated layering of metamorphic rocks near the surface (the depths down to a few hundreds of meters) of the crystalline crust. Two surveys were conducted in total length of the profiles about 500 m along a main traffic load across the East Ongul Island. The multi-channel acquisition systems were utilized with combining the dense geophones along the profiles. Seismic sources were adopted by combining the boom of a power shovel, a weight drop and hammer shots with their intervals in a few tens of meters. The obtained data include clear first P-arrivals in far offset distance. The energy of P-S converted waves was enhanced because of the characteristics of the seismic sources. Pre-stacked images could be expected to the information on metamorphic layering for several lithological structure composed by hornblende gneiss, garnet gneiss and pyroxene gneiss appearing as the surface bedrocks. The conducted shallow reflection surveys would give rise to one step for understanding tectonic formation of LHC, as one of the Pan-African mobile belts in Gondwana super-continent.

Passive Seismic Deployments from the Lützow-Holm Bay to Inland Plateau of East Antarctica: The Japanese IPY Contribution to Structure and Seismicity

Deployments of seismic stations in Antarctica are an ambitious project to improve the spatial resolution of the Antarctic Plate and surrounding regions. Several international programs had been conducted in wide area of the Antarctic continent during the International Polar Year (IPY 2007-2008). The “Antarctica’s GAmburtsev Province (AGAP)”, the “GAmburtsev Mountain SEISmic experiment (GAMSEIS)” as a part of AGAP, and the “Polar Earth Observing Network (POLENET)” were major contributions to the IPY. The AGAP/GAMSEIS was an internationally coordinated deployments of more than few tens of broadband seismographs over the wide area of East Antarctica. Detailed information on crustal thickness and mantle structure provides key constraints on an origin of the Gamburtsev Mountains;and more broad structure and evolution of the East Antarctic craton and sub-glacial environment. From POLENET data obtained, local and regional signals associated with ice movements were recorded together with a significant number of teleseismic events. Moreover, seismic deployments have been carried out in the Lützow-Holm Bay (LHB), East Antarctica, by Japanese activities. The recorded teleseismic and local events are of sufficient quality to image the structure and dynamics of the crust and mantle, such as the studies by receiver functions suggesting a heterogeneous upper mantle. In addition to studies on the shallow part of the Earth, we place emphasis on these seismic deployments’ ability to image the Earth’s deep interior, as viewed from Antarctica, as a large aperture array in the southern high latitude.

Intensity variations of the postnoon auroral bright spots observed at Zhongshan Station, Antarctica on August 8, 1999

In this paper we use the high speed multi channel meridian scanning photometer data and all sky TV camera images to analyze the intensity variations of the postnoon auroral bright sports of 557.7 nm and 630.0 nm emissions. Several results can be obtained from this paper. (1) Bright spots are rather transient features lasting typically for only a few minutes. (2) The intensity of the postnoon bright spots of 557.7 nm emissions can surpass 11 kR. The occurrence of the bright spots seems rather frequent. (3) The ratios of I(427.8)/I(630.0) and I(427.8)/I(557.7) during the bright spots occurring time show a positive peak and negative peak respectively. It qualitatively indicates that the average precipitating electron energies along the meridianal scan above Zhongshan Station increased as the bright spot appeared. And the intensification of the spot mainly was caused by the increasing of high energy (3 10 keV) flux. (4) Usually the bright spots are accompanied with the magnetic pulsation and the occurrence of multi band arcs.

Infrasonic Waves in Antarctica: A New Proxy for Monitoring Polar Environment

Characteristic infrasound waves are clearly recorded at Syowa Station (SYO), East Antarctica, involving physical interaction in surrounding environments at the continent and SouthernOcean. A Chaparral microphone type infrasound sensor is deployed at SYO during the International Polar Year (IPY2007-2008), the most diverse international science program held recently. Continuous recorded data in 2008-2010 indicate a contamination of background oceanic signals (microbaroms). The characteristic signals are identified as the “microbaroms” with peaks between 4 and 10 s in the records. The peak amplitudes of microbaroms may be enhanced by the extratropical cyclonic storms and wind noises in Southern Ocean. The microbaroms has relatively lower amplitudes during austral winters, which may be caused by the larger amount of the sea-ice extent around theLützow-HolmBaynear SYO, with decreasing the ocean wave loading effects. In addition, the large energy with intrinsic periods between 12 and 30 s are observable under excellent storm conditions, particularly in local winter. The oceanic effects appearing on infrasound data are modulated by the presence of sea-ice and explained by a relationship between the atmosphere-ocean-cryosphere systems. Microbaroms measurements could be a useful tool for characterizing ocean wave climate, as well as a new proxy for monitoring a regional environmental variation inAntarctica.

Observation and Data Archiving System of a Superconducting Gravimeter at Syowa Station, Antarctica

A superconducting gravimeter (SG, model TT70#016, GWR Instruments) was deployed for the first time in Antarctica in 1992 at Syowa Station. Observations began in April 1993. Although the SG was equipped with a 10 K cryocooler, its liquid helium (LHe) required refilling twice a year to maintain its superconducting state. The LHe was produced by a separate helium liquefier. After continuous gravity measurement with the SG for 11 years, it was replaced by a second SG (CT#043) with a 4 K cryocooler in December 2003 in order to reduce loads of person in charge for LHe production. Because the manufacturer could not supply a replacement 4 K cryocooler, this SG ceased measurement in November 2009. In January 2010, a new superconducting gravimeter (OSG#058) was installed and had recorded high-quality gravity time series with data acquired every second for more than five years without interruption. Because the personal computer (PC) controlling the observation and data acquisition is connected with PCs in Japan through an Intelsat satellite communication link, we can check the status of observations in real time. It is also possible to fix remotely certain problems with the gravimeter. The observed gravity data are transferred daily to a data server in Japan. Also included in the upload are diagnostic data of the gravimeter such as the temperature of the coldhead and environmental data such as atmospheric pressure. Plots of the daily data are publicly available. The raw data with a 1 s sampling interval are also released to registered researchers. The released gravity time series along with the environmental data are greatly useful for investigating solid earth dynamics especially in the long period bands. We provide necessary information to use these long-range data sets.

午后极光强度与太阳风-磁层耦合函数的相关

利用1997年和1998年南极中山站多通道扫描光度计的地面观测数据和Wind卫星在弓激波上游对行星际磁场和太阳风参数的观测数据,对午后高纬极光强度与太阳风-磁层耦合函数之间的相关性进行定量研究．研究表明,午后630．0 nm极光强度与太阳风-磁层耦合函数间有很好的相关,而557．7 nm的相关性差一些;在考察的所有耦合函数中,午后极光受太阳风电场和能量的影响更直接;同时,行星际磁场的时钟角对午后极光也有很强的控制作用．

Surface mass balance on Glacier No. 31 in the Suntar–Khayata Range, eastern Siberia, from 1951 to 2014

This study presents a 64-year （1951-2014） reconstruction of the surface mass balance of Glacier No. 31, located in the Suntar-Khayata Range of the eastern Siberia, where the ablation zone is characterized by the extensive dark ice surface. We use a temperature index-based glacier mass-balance model, which computes all major components of glacier mass budget and is forced by daily air temperature and precipitation from a nearby meteorological station. The glacier shows a mean annual mass balance of -0.35 m w.e.a-1 during the past 64 years, with an acceleration of -0.50 m w.e. a^-1 during the recent years. A cumulative mass loss of the glacier is -22.3 m w.e. over the study period, about 56% of which is observed during 1991-2014. In addition to the contribution of temperature rise and precipitation decrease to recent mass loss of the glacier, an experimental analysis, in which the clean and dark ice surfaces are respectively assumed to cover the entire ablation zone, indicates that dark ice surface, caused by insoluble impurities consisting of mineral dusts, eryoconite granules, and ice algae, plays a crucial role in the changing mass balance through enhancing melt rates in the ablation zone of the glacier.

Anthropogenic trace metals in an ice core at Vestfonna,Svalbard, Norway

A 211 m depth ice core observation was carried out at the top of the Vestfonna Ice Cap in Nordaustlandet, Svalbard, Norway in 1995. Chronology of the ice core was determined by tritium analysis and comparison to the volcanic eruption of Laki; the resulting accumulation rate is 0.34 0.35 m water eq.·yr -1 for the last 400 year. Concentrations of Al, V, Cr, Fe, Cu, Zn, As, Ag, Cd, Pb and U in an ice core have been determined by an inductively coupled plasma mass spectrometry (ICP MS) with a desolvated micro concentric nebulizer, which is a recent development and can achieve high sensitivity with low uptake rate of 60 mL/min. The concentrations of Pb, Cu, and Zn had increased from 1940s declined from 1970s to present. However, the profiles of Pb, Cu, and Zn were different and they seem to be influenced by the difference of sources. Since the ratios between Cu, Pb, and Zn in Svalbard is similar to that in French Alps, the source area of these elements is estimated to be Europe.

The extremely intense CNA events observed at Zhongshan Station in July, 2000

Using the ground observation data at Zhongshan Station of Antarctica during July 13 to 17, 2000, the intense absorption events associated with the activities of the solar active region R9077 are analyzed. It was shown that an intense polar cap absorption event lasted more than 3 days, which was caused by the solar proton event associated with the X5/3B major flare at 1024 UT on July 13. The polar cap event started at about 1040 UT on July 14, and lasted to about 1940 UT on July 17, with a typical day night variation. At the same time, the intense solar activities extremely disturbed the magnetosphere, therefore aurora substorms occurred frequently. The energetic particle precipitation from the magnetosphere caused several absorption spikes superposing on the background of polar cap absorption. One distinct event is the absorption enhancement that started at about 0300 UT on July 15, reached its peak of 26 dB at about 0645 UT and recovered at about 1110 UT on the same day, which was the strongest absorption event observed at Zhongshan Station since the imaging riometer installed in February, 1997. Another outstanding absorption spike with pulsation occurred at about 1753 UT on 14th, its peak reached to 6 dB.

Gravity Survey along the Mizuho Traverse Routes, East Antarctica: SEAL Seismic Exploration in 1999-2000

A gravity survey was conducted along the Mizuho traverse routes in austral summer of 1999-2000 by the 41st Japanese Antarctic Research Expedition (JARE-41). The main purpose of the survey was to obtain detail gravity anomaly along the traverse routes, where deep seismic exploration was simultaneously conducted in order to obtain a fine crustal structure of the Mizuho Plateau. By using SCINTREX (CG-3M) gravity meter, the survey was carried out at 160 sites with about 1 km interval in a distance of 190 km from S16 to Z20 on the traverse routes. Free-air and Bouguer anomalies were calculated using precise locations by GPS measurements, by taking into account an effect of the thick icesheet. The furrowed negative Free-air anomalies are identified around H192, where middle points of the whole traverse routes. Two bedrock elevation models derived both by seismic refraction analyses and radio-echo sounding might correspond to the bottom and the top of a mixture layer composed from ice-moraine rocks over the bedrock surface. Thickness of the crust estimated by Bouguer anomalies is 0.5 - 1 km larger toward inland at the terminal point of Z20 along the profile.

Infrasound Signals in Coastal Environment at Jang Bogo Station, Terra Nova Bay, Antarctica

Infrasound signals in Antarctica reflect physical interaction in the surface environments around the recorded area. In December 2015, an infrasound array by three sensors in the detectable frequency range of 0.1 - 200 Hz, combined with one broadband barometer was deployed at Jang Bogo Station, Terra Nova Bay, Antarctica. The two years of data by the broadband barometer contain characteristic signals that caused by surface environment nearby the station, mixing with local noises such as katabatic winds. Clear continuous signals by oceanic swells (microbaroms) were recorded with a predominant frequency of around 0.2 s. Variations of frequency context and amplitudes in the Power Spectral Density were considered as affected by sea-ice dynamics surrounding the Terra Nova Bay. Monitoring of microbaroms could contribute to understanding ocean wave climate, with other oceanographic, cryospheric and geophysical data in Antarctica. Infrasound data in Terra Nova Bay might be a new proxy for estimating environmental variations affected by global warming, cryosphere dynamics, together with volcanic eruptions in Victoria Land.

The polar ionosphere at Zhongshan Station on May 11, 1999, the day the solar wind almost disappeared

The solar wind almost disappeared on May 11,1999: the solar wind plasma density and dynamic pressure were less than 1cm^(-3) and 0.1 nPa respectively, while the interplanetary mag- netic field was northward. The polar ionospheric data observed by the multi-instruments at Zhong- shan Station in Antarctica on such special event day was compared with those of the control day (May 14). It was shown that geomagnetic activity was very quiet on May 11 at Zhongshan. The magnetic pulsation, which usually occurred at about magnetic noon, did not appear. The iono- sphere was steady and stratified, and the F_2 layer spread very little. The critical frequency of day- side F_2 layer, f_0F_2, was larger than that of control day, and the peak of f_0F_2 appeared 2 hours earlier. The ionospheric drift velocity was less than usual. There were intensive auroral E_s appearing at magnetic noon. All this indicates that the polar ionosphere was extremely quiet and geomagnetic field was much more dipolar on May 11. There were some signatures of auroral substorm before midnight, such as the negative deviation of the geomagnetic H component, accompanied with auroral E_s and weak Pc3 pulsation.

1999年5月11日太阳风几乎消失时的极区电离层

1999年5月11日太阳风几乎消失,其等离子体密度不到1 cm^(-3),动压不到0.1nPa,而行星际磁场持续北向.对这一特殊事件日和控制日(1999年5月14日)南极中山站极区电离层多手段观测结果进行了对比分析.结果表明中山站在1999年5月11日地磁活动极为宁静,通常在地磁当地时的中午前后出现的地磁脉动在这一天几乎没有;电离层成层明显而稳定,F_2层扩展很小;日侧F_2层临界频率明显高于控制日,且f_oF_2的峰值早约2 h出现;电离层漂移速度有所减小;在地磁当地时的中午附近出现了很强的极光E层,这一切都说明极区电离层异常平静,地磁场的偶极化更为明显.但子夜前出现有类似极光亚暴的征兆,如地磁H分量明显的负扰。

Multiple ground-based observations at Zhongshan Station during the April/May 1998 solar events

Simultaneous observations at Zhongshan Station, Antarctica, during May 1-7, 1998 are presented to show the responses of the polar ionosphere to the April/May 1998 solar events. One of the main geo-effects of the solar events resulted in the major magnetic storm on May 4. At the storm onset on May 2 the ionosphere F2 layer abruptly increased in altitude, the geomagnetic H-component started negative deviation and the spectral amplitude of the ULF wave intensified. Both large isolated riometer absorption and large negative deviation of the geomagnetic H-component occurred at about 0639UT. There was a time lag of about one hour and ten minutes between the storm onset and the IMF southward turning, as measured by the WIND satellite. The polar ionosphere was highly disturbed, as shown by frequent large deviations of the geomagnetic H-component, large riometer absorption events and strong ULF waves in all the courses of the storm. The absorption increased greatly causing the digisonde to be blackout most of the time. However, the data still showed a substantial decrease in the F2 electron density and oscillation of the F2 layer peak height with an amplitude exceeding 200 km.