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In the recent study, unique ecosystemic existence became clear in the lakes around the Syowa Station. On the lake bottom of Naga, Hotoke, and Kuwai Lakes in Skarvsnes on the Sôya Coast, a cone-shaped biological community structure mainly consisting of mosses, algae and cyanobacteria have been confirmed. On the other hand, the process leading to fixation and growth from the invasion of the creature has not been elucidated. Conventionally, these lake surveys have been carried out by scuba diving. However, an extensive, effective investigation is difficult because time limitation is rigid for a diving investigation in the low-temperature environment. Therefore, it is difficult to investigate the distribution of lake bottom communities widely and efficiently in various lakes, and it is one of the major factors that limit the progress of research. In this study, we aimed to create visual information as “Habitat mapping” from the lake surface and underwater by developing a new ROV, which is usable at the Antarctic lake surveys during the 58th and 59th Japanese Antarctic Research Expeditions.

At Syowa Station, Antarctica, the baseline values, or the difference between the absolute and continuous measurements, vary relatively significantly in summer. They are possibly due to artificial disturbances from magnetized objects, and/or changes of the instrumental environment such as involving the tilt and temperature of the sensor for continuous observations. To evaluate the effect of the sensor tilt, we continuously monitored its behavior with electronic tiltmeters over two successive summer seasons (Jan.-Feb. 2013, Nov. 2013-Feb. 2014), while also intensifying the frequency of the absolute observation. The variability of the tilt was found such that, its angular changes in the East-West and North-South directions were 30 to 50 and 10 arcseconds, respectively. The observed variations of the baseline values can be attributed primarily to the sensor tilt changes, with its contribution estimated to be up to 60 to 100% for the D component and 30 to 40% for the H and Z components.

The air-based solar heating system was mounted on external walls of the sustainable energy hut at Syowa Station, Antarctica for the first time. To confirm the usefulness of the heating system, the plans of measurement of thermal condition in the building were prepared by National Institute of Polar Research. A part of the measurement was executed in the wintering of 2017 by the 57th Japanese Antarctic Research Expedition. Using the results of the field measurement, basic performance of air-based solar heating system adopted in the building at Antarctic region was assembled. For being put to practical use of the air-based solar heating system in cold regions like Antarctic, Some preliminary tests were executed in March 2009 at Tomakomai City, Hokkaido, one of the cold region in Japan. The heating system used in the demonstrating test at Tomakomai had same specifications of solar panels constructed later at Syowa Station. The result which was compared and inspected about heat collection efficiency of solar panel at Syowa Station and the cold region of Japan (Tomakomai, Hokkaido) was indicated in this paper. The air heating system will be practicable to use on cold regions as Syowa Station, Antarctica in the sunny season. Long time of daylight will be expected on the facilities of the building-wall as the sun moves on low orbit at Syowa Station.

1973年11月22日,南極地域観測統合推進本部の総会において,以下の22の地名が新たに命名された.なお,国立極地研究所の創立にともない,南極地名委員会は,国立極地研究所所長に対する助言機関として再発足した.

International audience; The expansion of human activities in offshore maritime regions has outpaced the development of scientific knowledge and cooperative governance across these areas beyond national jurisdiction (ABNJ). In this context, current negotiations by the United Nations aim for an international legally-binding instrument to improve governance and sustainable use of biodiversity in ABNJ. Penguins are among the most threatened seabird groups today, notably at sea from fisheries and oiling. Here, we examine the available information on penguins’ movements and evaluate their use of ABNJ across species and life-cycle stages. We highlight that in most of the 18 extant penguin species, the birds may undertake spectacular migrations, seasonally or throughout life-cycle stages. Long-range movements were reported in 16 species, with trans-jurisdictional distribution in 14 species, including 13 in ABNJ. Species richness in ABNJ varied extensively according to oceanic region, and also varied according to season. Transboundary movements, notably to ABNJ, are thus remarkably prevalent among penguin species. Consequently, provisions of the treaty under negotiation may crucially benefit penguin conservation, notably by creating a uniform legal framework to designate protected areas in ABNJ, and by promoting the precautionary approach to extraction activities. However, the seasonally-dynamic utilisation of ABNJ by penguins supports the pertinence of adding innovative protection tools, such as mobile Marine Protected Areas, to the negotiations for a more adequate protection of marine biodiversity. Underlining penguins’ remarkable connectivity to the high seas can thus further strengthen this instrument aiming to protect a global ocean commons heritage of mankind.

This study was financially supported by the following institutions: the WWF-UK through R. Downie, the Japanese Mombukagakusho and the Japanese Society for the Promotion of Science, the Zone Atelier Antarctique et Subantarctique –LTER France of the CNRS. The Southern Ocean is currently experiencing major environmental changes, including in sea‐ice cover. Such changes strongly influence ecosystem structure and functioning and affect the survival and reproduction of predators such as seabirds. These effects are likely mediated by reduced availability of food resources. As such, seabirds are reliable eco‐indicators of environmental conditions in the Antarctic region. Here, based on 9 years of sea‐ice data, we found that the breeding success of Adélie penguins (Pygoscelis adeliae) reaches a peak at intermediate sea‐ice cover (ca. 20%). We further examined the effects of sea‐ice conditions on the foraging activity of penguins, measured at multiple scales from individual dives to foraging trips. Analysis of temporal organisation of dives, including fractal and bout analyses, revealed an increasingly consistent behaviour during years with extensive sea‐ice cover. The relationship between several dive parameters and sea‐ice cover in the foraging area appears to be quadratic. In years of low and high sea‐ice cover, individuals adjusted their diving effort by generally diving deeper, more frequently and by resting at the surface between dives for shorter periods of time than in years with intermediate sea‐ice cover. Our study therefore suggests that sea‐ice cover is likely to affect the reproductive performance of Adélie penguins through its effects on foraging behaviour, as breeding success and most diving parameters share a common optimum. Some years, however, deviated from this general trend, suggesting that other factors (e.g. precipitation during the breeding season) might sometimes become preponderant over the sea‐ice effects on breeding and foraging performance. Our study highlights the value of monitoring fitness parameters and individual behaviour concomitantly over the long‐term to better characterize optimal environmental conditions and potential resilience of wildlife. Such an approach is crucial if we want to anticipate the effects of environmental change on Antarctic penguin populations. Postprint

9 pags., 3 figs., Mercury is a pollutant of global concern, especially in the Arctic, where high levels are found in biota despite its remote location. Mercury is transported to the Arctic via atmospheric, oceanic and riverine long-range pathways, where it accumulates in aquatic and terrestrial ecosystems. While present-day mercury deposition in the Arctic from natural and anthropogenic emissions is extensively studied, the control of past climate changes on natural mercury variability remains unknown. Here we present an Arctic mercury record covering the Last Glacial Termination to the early Holocene epoch (15.7–9.0 thousand years before 2000 ce), collected as part of the East Greenland Ice-Core Project. We find a threefold increase in mercury depositional fluxes from the Last Glacial Termination into the early Holocene, which coincided with abrupt regional climate warming. Atmospheric chemistry modelling, combined with available sea-ice proxies, indicates that oceanic mercury evaporation and atmospheric bromine drove the increase in mercury flux during this climatic transition. Our results suggest that environmental changes associated with climate warming may contribute to increasing mercury levels in Arctic ecosystems., It is supported by funding agencies and institutions in Denmark (A. P. Møller Foundation, University of Copenhagen), USA (US National Science Foundation, Office of Polar Programs), Germany (Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research), Japan (National Institute of Polar Research and Arctic Challenge for Sustainability), Norway (University of Bergen and Trond Mohn Foundation), Switzerland (Swiss National Science Foundation), France (French Polar Institute Paul-Emile Victor, Institute for Geosciences and Environmental research), Canada (University of Manitoba) and China (Chinese Academy of Sciences and Beijing Normal University). A.S. acknowledges the ‘Programma di Ricerca in Artico’ (PRA, project number PRA2019-0011, Sentinel) for supporting this work. A.S.-L. received funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation Programme (project ERC-2016-COG 726349 CLIMAHAL). This work represents a contribution to CSIC Thematic Interdisciplinary Platform PTI POLARCSIC. A.S.M. acknowledges the Indian Institute of Tropical Meteorology (IITM), funded by the Ministry of Earth Sciences (MOES), Government of India (GOI). F.W. received funding from the Canada Research Chairs Program. T.E., C.M.J. and C.Z. acknowledge the long-term support of ice-core research by the Swiss National Science Foundation (SNSF) under the project numbers 200020_172506, 200020B_200328 and 20FI21_164190 as well as the Oeschger Center for Climate Change Research. H.A.K. received funding from the DFF Inge Lehmann grant 1131-00007B ‘Holocene sea ice variability in the Arctic’. ELGA LabWater, High Wycombe, UK, supplied the pure-water system used in this study.

北極ヘイズが頻繁に出現する春季(3-4月),清浄な大気へ変化する時期(5-6月)の北極対流圏内のエアロゾル粒子の組成とその混合状態の空間分布に関して知見を得るため,日本-ドイツ共同で航空機を用いたエアロゾル観測を2000年3-4月(ASTAR 2000)と2004年5-6月(ASTAR 2004)にスバールバル諸島周辺で実施した.春季には酸性状態の硫酸粒子が主要だったのに対し,夏季に移行する時期(6月)には中性の硫酸塩粒子(おそらく(NH_4)_2SO_4)の割合が増加していた.北極ヘイズ現象下ではススを含む粒子の割合が増加し,その多くは外部混合状態で存在していた.一方,バックグラウンド時(非北極ヘイズ時)には,スス粒子の割合は減少し,多くが硫酸(塩)粒子と内部混合した状態だった.ここでは,海塩粒子変質の鉛直変化や土壌粒子の空間分布についても報告を行う., Airborne aerosol measurements around the Svalbard Archipelago were carried out in March-April, 2000 (ASTAR 2000) and in May-June, 2004 (ASTAR 2004) for better understanding of the spatial distribution of aerosol constituents and their mixing states. Major aerosol particles were sulfate particles in both campaigns. In ASTAR 2000 (spring), acidic sulfate particles (mostly H_2SO_4 droplets) were dominant, whereas the relative abundance of neutralized sulfate particles (probably (NH_4)_2SO_4) increased in the transition period (ASTAR 2004). Under Arctic haze conditions, higher relative abundance of aerosol particles containing soot was observed. Most of the soot collected during the haze was present as "external mixing states". In contrast, soot dominantly existed as "internal mixture" with sulfate particles under the background (non-haze) conditions. In the transition period (June in ASTAR 2004), the relative abundance of aerosol particles containing soot decreased clearly. Vertical features of sea-salt modification and spatial distribution of mineral particles are also reported.

「海鷹丸を用いた南極研究ワークショップ2008」を東京海洋大学品川キャンパスにおいて2008年8月8日に開催した.参加者は36名であった.2002/03年,2004/05年,2005/06年,2007/08年シーズンに行われた東京海洋大学「海鷹丸」の南極海研究航海(それぞれ,UM0203,UM0405,UM0506,UM0708航海)で得られた結果が報告された後,得られたデータやサンプルの管理及び成果取りまとめについて議論した., A workshop "Southern Ocean Study by RT/V (research and training vessel) Umitaka-Maru, 2008" was held on 8th August 2008 at the Shinagawa Campus of the Tokyo University of Marine Science and Technology (TUMSAT), with 36 participants. Results obtained during RT/V Umitaka-Maru (TUMSAT) cruises in austral summer of 2002/03 (UM0203), 2004/05 (UM0405), 2005/06 (UM0506), and 2007/08 (UM0708) and the current status of data were reported. Data management and synthesis of scientific results were discussed.

第49次日本南極地域観測隊(第49次)夏隊において,湖沼観測として湖沼環境観測,生物・生態学的研究試料としての湖水と湖底の生物群集採取,及び現場実験を宗谷海岸露岩域にある複数の湖沼で実施した.この湖沼観測報告は南極観測事業第VII期計画の一般プロジェクト研究(P3)「極域環境変動と生態系変動に関する研究」及びモニタリング研究観測(M4)「生態系変動のモニタリング」の両課題にかかわる観測を記録したものである.野外観測は2007年12月22日から2008年2月13日の期間,砕氷船「しらせ」が昭和基地沖近傍に滞在中に実施した.今回は夏季の湖沼環境変動と湖底の生物(藻類群集)の応答を集中的に観測すべく,スカルブスネスの長池にて観測とサンプリング・現場実験を繰り返し実施する一方,きざはし浜生物観測小屋から徒歩日帰り圏内にある周辺の14湖沼,及びヘリコプターを利用した日帰り観測にてスカルブスネス東部の4湖沼,及び他の露岩,スカーレンにあるスカーレン大池,ラングホブデ域の雪鳥池・東雪鳥池,ぬるめ池にて湖沼水質環境観測と試料採集を適宜実施した.このうち,スカルブスネス東部のなまず池 (仮称)では潜水による水中設置ビデオ装置の回収と,湖底のコケ類・藻類が作り上げている「とさか・筍状」の群落の採集,ラングホブデぬるめ池では湖底から小型カイアシ類の定量サンプリングを実施,これらを研究試料として日本に持ち帰ることができた.また,第47次隊により雪の堤防の決壊の発見(第46次越冬期間中に決壊したとみられる)が報告されたラングホブデ南部の平頭氷河末端にあった「氷河池」(仮称)の現状視察も実施,決壊前後での3m以上と思われる大幅な水位変動痕からフィルム状の生物試料を採集し持ち帰った., Observations on the limnological properties, samplings of waters and bottom assemblages for biological and ecological studies, and some field experimental studies at several lakes in Soya Coast ice-free areas, were carried out during the austral summer season in the 49th Japanese Antarctic Research Expedition (JARE), 2007-2008. These studies were planned as one of the research projects named, "Studies on the changes of polar environments and ecosystems (P-3)" and the monitoring studies named "Monitoring for ecosystems (M-4)" during the 7th term of the Japanese Antarctic Research Expedition Plans. Field studies were done from 22 December 2007 to 13 February 2008, while our Ice Breaker Shirase stayed at/near off Syowa Station. To clarify the relationships among seasonal changes of environmental factors and biological responses, frequent field observations were performed at Naga Ike, one of the freshwater lakes in the Skarvsnes ice-free area. General limnological and biological samplings at the other lakes in the area (14 lakes near the Kizahasi Beach field base camp) were also done during the term. Observations and samplings distant from the base camp, four lakes in eastern Skarvsnes, a lake in Skallen, and three lakes in Langhovde, were also done using a helicopter for transportation. From Namazu Ike (temporary name) in eastern Skarvsnes, submersible video cameras were retrieved and so-called `algal crest', benthic moss-algal assemblages, were sampled by scuba diving. Benthic copepods were sampled quantitatively from Nurume Ike in Langhovde. From Hyoga Ike (temporary name), a snow-dammed glacial lake which lost its water by recent breakage (during the JARE-46 wintering period), thin bio-film samples were collected from the present lake shore formerly part of the lake bed.

1992年から氷床流動観測を目的としたGPS (Global Positioning System: 全地球測位システム)観測が開始された.最初は沿岸からドームふじ基地へのトラバースルート沿いに設けた11地点を基本観測点として,内陸旅行中に適宜GPS観測を行った.その後,白瀬流域の主流線沿いと等高線沿い,ドームふじ基地南方へと観測地域を拡大した.氷床流動に関しては,白瀬流域の下流ほど氷床流動速度が大きい.また白瀬流域において,従来から観測されている氷床表面の低下が確認され,この低下速度は0.1-0.2m/年であった., Surface ice sheet flow velocity has been observed using the differential GPS (Global Positioning System) method since 1992. The basic GPS stations along traverse routes from S16 to Dome Fuji were set up at 11 sites and the GPS observations were performed during inland traverse expeditions. After that, the observational area was expanded along contour lines and the main stream line in the Shirase drainage basin to the south of Dome Fuji Station. The flow velocities at GPS stations are reported. The thinning of the ice sheet surface reported from the past was observed in Mizuho Glacier basin. The thinning rates were 0.1-0.2m/year.

南極中央高地は水蒸気量が極めて少なく低温で,かつ気流の乱れが少ないため,地球上で最も優れた天体観測が行える場所である可能性が高い.その調査の一環として,ドームふじ基地においてSODARによる接地境界乱流の測定を,第48次南極地域観測隊に委託して行った.2006年12月21日～2007年1月14日の連続25日間の有効な測定データ(乱流強度,3次元風速)が得られたので報告する.太陽高度に対応した乱流層高度の明瞭な日変化が見られた.また装置輸送時に測定した加速度計の記録も合わせて報告する., The Antarctic plateau can be the best astronomical observatory site on the earth because of its very dry air and low temperature. We have observed atmospheric turbulence in the boundary layer (up to the altitude of 1000m above ice surface) by SODAR during JARE-48. We obtained valid continuous data of turbulence strength and three dimensional wind speed from Dec. 21, 2006 to Jan. 14, 2007. Our data show clear correlation between turbulent layer height and solar elevation. Also reported is the jolt measured during transportation from Cape Town to Dome Fuji.

南極医学医療研究集会は,わが国の南極医学研究と医療問題についての研究成果を報告・討論し,次期の観測隊における医学研究に寄与することを目的として毎年行われている.2006年の本研究集会は8月26日,国立極地研究所講堂で行われた.27施設から42名が参加し18の演題報告がなされ,近年では最大規模の研究集会となった. 参加者は越冬経験医師をはじめ,共同研究を行っている大学や研究機関の研究者,関連領域の研究を行っている宇宙開発機構やスポーツ科学研究所などの研究者,南極に興味のある一般病院の臨床医など多彩であった. 2004年より昭和基地に導入されたテレビ会議システムを活用して,昭和基地の医師もリアルタイム映像で討論に参加した.また韓国,中国の越冬医師が初めて参加した.これは3カ国の極地研究所による事前の準備と連携により実現した.集会では各国の南極基地の医療状況や医学研究活動が報告され,活発な意見交換がなされた.南極医学医療研究分野におけるアジア連携の端緒となることが期待される., A workshop on Antarctic Medical Research and Medicine 2006 was held at the National Institute of Polar Research (NIPR) on 26 August, 2006. Forty two participants from 27 institutes attended. The members consist of medical doctors with Antarctic experience, human biologists, research scientists in other fields, logistic staff members of the expedition and also medical doctors interested in Antarctica. The current resident doctor at Syowa Station joined the discussion through a telecommunication system. Doctors with Antarctic experience from China and Korea also participated in the workshop. They gave presentations on their Antarctic activities, followed by an active discussion session. Eighteen presentations were given on various topics, including the International Polar Year (IPY) 2007-2008 in medical research, space medicine, telemedicine, an international comparative study of medical operations, psychological surveys, Antarctic high-altitude medicine, Legionella surveillance and nutritional studies.

The Adelie penguin, Pygoscelis adeliae, an important component of the Antarctic marine ecosystem, is closely associated with sea ice. Ten breeding populations along the Soya Coast of Lutzow-Holm Bay have been monitored since the 1960s by the Japanese Antarctic Research Expedition and shown to be increasing. In most colonies, small peaks of population increase were observed in the late 1980s with a rapid increase from the mid 1990s. Frequent sea ice break-ups in Lutzow-Holm Bay in the mid 1980s and since the late 1990s are thought to have induced the population increase through increased subadult survival and preferred prey availability. Population monitoring therefore needs to be continued carefully in relation to the environmental changes.

Despite a number of limitations, stomach temperature recorders are still commonly used to determine feeding activity in free-ranging marine predators. In this regard, it is important to improve the detection rate of these systems by, for instance, increasing the probability that a cold prey touches the sensors. In the present study, we compared the detection rates and mass estimations of water and fish prey ingested by captive king penguins using a two-point temperature recorder (STL) and a single, but large, point recorder (SICUP). Prey items were of different masses (5-45 g) and delivered at different frequencies (high vs. low). Ingestions were recorded as precipitous drop followed by an exponential rise (PDER). Overall, 57.9, 56.0 and 70.0% of the ingestions were detected by the SICUP and the upper and lower sensors of the STL, respectively. Our study confirmed that employing two sensors improves the detection of prey ingestion, but the detection of very small prey items remains insufficient and prey items swallowed at short intervals are detected as cumulative ingestion events. Nonetheless, the total mass of food ingested can be estimated with more than 70% confidence.

NORPAC net samplings at three stations along a south-north transect on ca. 140°E were conducted in the Indian sector of the Southern Ocean from March 10 to 12 in 2002 during the 43rd Japanese Antarctic Research Expedition. The survey was held to examine the community structure and abundance of Copepoda in the seasonal ice zone of the Southern Ocean. A total of 15 species of copepod were identified at the stations. For nine species of copepod, Microcalanus pygmaeus, Calanus simillimus, Rhincalanus gigas, Euchaeta antarctica, Clausocalanus laticeps, Scolecithricella minor, Metridia lucens, Haloptilus oxycephalus and Oithona frigida, disparities of the distributions between the south of the Southern Boundary (SB) and the north became apparent. As here was a distinct difference of, about 2°C, in the sea surface temperature between the south and north of the SB, these disparities were considered to be influenced by the difference in the physical structure in the ocean, in particular by the water temperature, which was driven by the SB. Among Calanoides acutus, Calanus propinquus, and R. gigas, the earlier copepodite stages were observed at higher latitudes at all stations. This trend was considered to be a result of the sea ice retreat, which caused a later spawning period for Copepoda. In addition, an interaction between the sea ice conditions and the community structure of copepod along 140°E was suggested.

The Alfred Wegener Institute for Polar and Marine Research (AWI) has in the past operated two ski equipped aircraft (Dornier Do228-101) for scientific and logistic purposes in polar regions-called POLAR 2 and POLAR 4. Both aircraft are easily able to be adapted to different science programs. Aero-geophysical instrumentation and various atmospheric systems are available. In recent years, a long and fruitful cooperation with the National Institute of Polar Research (NIPR), Tokyo, has been established, whereby so far three joint airborne campaigns have been already performed in the Arctic, namely ASTAR 2000 (Arctic Study of Tropospheric Aerosol and Radiation), AAMP 2002 (Arctic Airborne Measurement Program), and ASTAR 2004. The ANTSYO (Antarctic flight missions at Syowa region: Airborne Geophysical, Glaciological, and Atmospheric Research in East Antarctica) operations of the AWI research aircraft, POLAR 2, started in the season 2005/06, from S17, near Syowa Station in December 2005. Running such surveys presents a logistical challenge that can only be met with the combined support of Alfred Wegener Institute, Bremerhaven, and the NIPR, Tokyo. Therefore, both national Antarctic programs put their logistical capabilities together in order to perform the first extensive airborne missions in this area over a period of three Antarctic summer seasons (2005/06 till 2007/08).

平成18年2月2,3日に国立極地研究所講義室にて,「両極域から視た地球内部の不均質構造とダイナミクスに関する研究集会」が開催された(参加者計32名).極域の固体地球物理科学に関連する研究者が集まり,最新の研究成果の発表と学際的な情報交換を行い,また今後の研究の取り組み方を議論した.第1部(極域から視た地球内部の科学的成果)では,地球中心核・最下部マントル～不部マントル・地殻における様々な地震学的不均質構造とその変動現象(ダイナミクス)に関する発表をはじめ,南極プレート周辺の地震活動,また2004年12月のスマトラ沖巨大地震に関連した研究が紹介された.第2部(極域における将来計画の展望)では,地震波伝搬モデリングなどについての今後導入すべき解析手法,インフラサウンド観測や高サンプリングGPS観測等,極域における様々な時空間スケールでの特徴的な振動現象を解明するための斬新なアイデアが紹介された.2日目は,国際極年2007-2008に関連した観測計画の紹介をはじめ,東ドロンニングモードランドを中心に今後の国際共同研究の具体的な進め方について議論した., A workshop on "Heterogeneous structure and dynamics of the Earth's interior viewed from polar regions" was held on 2nd-3rd February 2006, at the National Institute of Polar Research with 32 participants. The meeting provided the opportunity to exchange valuable information involving solid Earth studies around the polar region, followed by a discussion about future plans. The first section of the workshop covered the present status of scientific results, such as insights of the inner structure and dynamics of the Earth viewed from high latitude. Significant results concerning the heterogeneous structure were demonstrated from the depths ranging from the deep interior of the Earth to the upper mantle and overlying crust. Several remarkable topics concerning the Sumatra Earthquake on December 2004, were also presented involving seismic activity of the Antarctic Plate, free oscillation of the Earth, Tsunami waves, dynamic triggering, and so on. The second section of the workshop treated future plans both for the development of new analytical methods and for observations in the polar regions. Multidisciplinary studies, moreover, were proposed for the Antarctica including high-density super-conducting gravimetric network, infrasonic observations, high sampling GPS recording, ice-quake monitoring, etc. Finally, several international activities in Eastern Dronning Maud Land were discussed with regard to the International Polar Year (IPY) in 2007-2008.

Vertical distributions of atmospheric aerosol particles were measured nine times up to 5200 m a.s.l. using an aircraft over Syowa Station, East Antarctica during September-December 2004. Measurements were made for number concentrations of condensation nuclei (CN, Dp>10 nm), number-size distribution larger than 0.3 μm diameter, air temperature, humidity, and GPS position. During spring, the vertical profile of CN concentration showed large variability (100-1000 cm^(-3)), but it was mostly constant in summer. Vertical profiles of number-size distribution larger than 0.3 μm showed a systematic shift at altitudes greater than 4000 m. Both concentrations of aerosol number for Dp>0.3 μm and integrated volume between 0.3 and 1.0 μm showed constantly lower values at altitudes greater than 4000 m. These data suggest that the shift of aerosol parameters results from depletion of coarse particles such as sea salts. Maximum concentrations of the volume and CN were obtained respectively from the profiles on 7 October and 29 November 2004. These events are interpreted as sources and transport processes based on synoptic meteorological data, an ocean color index produced by SeaWiFS, and backward air trajectory analysis.

弱光環境の定着氷下で高濃度のクロロフィルaが存在する要因を明らかにするため,2004-05年夏季にオングル海峡にて海洋観測を行った. 観測されたクロロフィルa濃度は,これまで報告された値より小さく,最大で7.6 mg/m3であった.しかし,観測期間中の表層の硝酸塩,リン酸塩の減少量は大きく,定着氷下の一次生産は活発であったと考えられる.一方,定着氷下の流向及び流速は,概ね北向きに平均4.4 cm/sの流れが存在した.それゆえオングル海峡の定着氷下の水塊は,8日間前には約30 km南方の海域に存在したと考えられる.リュツォ・ホルム湾宗谷海岸の定着氷は,オングル海峡周辺より融解が早く,海中光量が増加して植物プランクトンの増殖できる環境が早く整う. したがってオングル海峡の定着氷下で観測される多量の植物プランクトンは,宗谷海岸沖の開水面域・薄氷域で増殖し,海流に乗って輸送され存在する可能性が考えられる., Time series oceanographic observation was carried out in Ongul Strait during the austral summer of 2004/05 in order to clarify the reason why dense chlorophyll a can exist under fast ice where the light condition is unfavorable for ordinary phytoplankton. Chlorophyll a concentration observed in this study was smaller than that previously reported, and the maximum was 7.6 mg/m3. However, the decrease of nitrate and phosphate concentration in surface water during the observation period was large, and primary production under the fast ice seemed to be active. At the same time, a northward surface current of 4.4 cm/s was observed under the fast ice. Therefore, the water mass in Ongul Strait is believed to have been about 30 km south of the strait 8 days earlier. The fast ice in the Sôya coastal area in southeastern Lützow-Holm Bay melts earlier than that around Ongul Strait. Underwater light intensity increases and a favorable condition for multiplication of phytoplankton exists in early summer. Consequently, it is believed that the high biomass of phytoplankton observed under fast ice in the Ongul Strait increased in open water and under thin ice in the southern area (off the Sôya Coast area) and was transported northward by the current.

A Micro-Pulse Lidar (MPL) has been operated in Ny-Alesund, Svalbard (78°55'N, 11°56'E, 0.010 km msl) to collect zenith scattering profiles of aerosols and clouds since 1998. The Ice, Cloud, and land Elevation Satellite (ICESat) was launched by NASA in January 2003 with a single payload instrument, the Geoscience Laser Altimeter System (GLAS), designed for active remote sensing of the atmosphere as well as ice sheet height change in the cryosphere. Overpass experiments for ground validation of the ICESat/GLAS atmospheric measurements were performed in 2003 and 2004. Two case-studies comparing lidar measurements from space-borne GLAS and ground-based MPL in the Arctic are described here for a geometrically thick but optically thin cloud and a geometrically thin but optically thick cloud. The result validates the basic procedure for cloud signal processing and attenuation correction of the GLAS data.

南極・昭和基地では,2004年2月よりインテルサット衛星回線を利用した通信システムが立ち不がり,基地外との情報交換・通信能力が格段に向不した.昭和基地の地震モニタリング観測で収録される波形データは,これまでもインマルサット衛星回線によりUnix-to-Unix-Copy(UUCP)伝送を行ってきたが,収録サーバーを更新(geotail; IP:133.57.32.60)し,インテルサット回線を用いた伝送方式に変更した.短周期地震計(HES)と広帯域地震計(STS-1)の20 Hz連続サンプリングデータが,定期的に国内(国立極地研究所サーバー)へ自動伝送される.また常時IP接続により国立極地研究所から直接に,昭和基地の収録装置(geotail, 及びAD変換機Q680; IP:133.57.32.67)への遠隔ログインと各種コマンド操作が可能になり,国内から観測機器への制御が格段に容易になった.さらに,ネットワークカメラサーバーによるリモート監視を行うことで,データ収録状況の常時モニタリングが可能になり,現地での見回りの労力が半減した. 本稿では,インテルサット衛星回線の導入に伴う昭和基地の地震モニタリング観測・データ伝送システムの具体的な向不点について紹介する.また,将来のリモートデータ収録を視野に入れた,インテルサット回線を利用した遠隔データ収録試験について報告する.さらに,伝送データのアーカイブ方法と公開内容についても紹介する., The seismic observation system at Syowa Station, Antarctica, was partially improved in association with introduction of the INTERSAT communication link from February 2004. The workstation used for acquisition of the seismic signals was replaced by a new one (geotail; IP:133.57.32.60) at the Earth Science Laboratory (ESL). Digital waveform data have been automatically transmitted from a 24-bit A/D converter (Q680; IP:133.57.32.67) to the workstation on TCP/IP protocol by using `Comserv' software. Among several kinds of seismic signals, 20 Hz continuous data of both short-period (HES) and broadband (STS-1) seismometers have been automatically transferred once a day to the National Institute of Polar Research (NIPR) by using the Unix-to-Unix-Copy (UUCP) protocol via the INTERSAT link. Besides remote operations and monitoring data from NIPR to the acquisition system at ESL, Internet access to the observation system at Syowa Station has significantly improved. For instance, network cameras were introduced both in ESL and the Seismological Hut, which provide real-time images for monitoring related instruments, analogue recorders and room temperature measurements, even when nobody can approach the ESL or Hut during severe weather. The above improvements involving the INTERSAT link have brought several advantages not only to the data transport/communication processes but also to reduce daily maintenance efforts at the Station. In this report, several topics are demonstrated concerning improvements of seismic monitoring observations associated with the INTERSAT link, followed by introduction of the data archive and publication via the Internet.

Large mafic to ultramafic blocks in felsic gneisses on the northern part of the Howard Hills, Napier Complex, East Antarctica are accompanied by phlogopite-bearing pyroxene granulite occurring in the margins of the block. In order to understand the crustal evolution of the Napier Complex, especially regarding the thermal history after peak metamorphism, Rb-Sr, Sm-Nd and U-Pb isotopic analyses have been carried out on different minerals from the phlogopite-bearing pyroxene granulite and adjacent orthopyroxene felsic gneiss. Zircon grains from the orthopyroxene felsic gneiss yielded near concordant U-Pb isotopic ages of about 2.5Ga by conventional isotope dilution methods and defined a discordia with 2.44±0.02Ga lower intercept age. This age shows the waning stage of UHT granulite facies metamorphism in the Howard Hills. Rutile fractions from pyroxene granulite yielded a near concordant U-Pb isotopic age of about 1.5Ga. This age is interpreted as the final thermal episode, excepting local igneous intrusions, in the Howard Hills region. Fluorophlogopite fractions from pyroxene granulite yielded Rb-Sr model ages of about 1.85Ga, although evidence of retrograde metamorphism with fluid activity or deformation were poor in the pyroxene granulite. An internal Sm-Nd isochron of whole rock and orthopyroxene and feldspar separated from the same sample shows 1.85±0.15Ga. The Rb-Sr phlogopite model age, along with the Sm-Nd internal isochron age, records the time when the rocks of the Howard Hills underwent medium to high grade metamorphism at temperatures well above the currently accepted closure temperature of biotite (about 300-350°C ).

Mafic metamorphic rocks are widely distributed through the Lutzow-Holm Complex (LHC) of East Antarctica, as layers between or enclaves within metasedimentary and metaigneous lithologies. It has been inferred that the peak metamorphic grade of the LHC progressively increases in a southwestern direction from amphibolite-facies to granulite-facies conditions, with mineral assemblages in the mafic metamorphic rocks changing from hornblende (magnesiohornblende)±biotite+plagioclase to orthopyroxene+clinopyroxene±hornblende (pargasite, magnesiohasting-site and tschermakite)±biotite±garnet+plagioclase. Field relationships suggest that amphibolite-grade mafic metamorphic rocks derive from mafic magma intruded into metasedimentary units, whereas granulite-facies mafic metamorphic rocks are a mixture of detrital blocks and mafic sill or intrusions. Major and trace element compositions of mafic metamorphic rocks are similar to those of igneous rocks of tholeiite affinity, and can be divided into volcanic-arc basalt (VAB)-type or mid-ocean ridge basalt (MORB)-type compositions. On a regional scale, VAB-type lithologies are predominant in amphibolite-facies areas, and MORB-type lithologies predominate in granulite-facies areas. On the basis of HFSE concentrations and Nb/Y ratios, MORB-type lithologies have T-type and E-type MORB compositions with oceanic plateau basalt and back-arc basin basalt affinities, and are occasionally found in the field intercalated with metasedimentary layers, characteristic of magmatism and sedimentation cycles in a marginal sea basin setting. Such field relationships provide information on the tectonic environment of protolith formation in the LHC. Various crustal components have been amalgamated into a relatively narrow mobile belt, which was subjected to high-grade metamorphism during the final closure of oceanic basins as a result of continent-continent collision.

We report here the geology of Byobu Rock and Gobanme Rock outcrops hitherto unmapped in the Prince Olav Coast, East Antarctica. Both these outcrops expose high-grade metamorphic and igneous rocks. The metamorphic rock units comprise mainly of gneisses migmatized to variable extent and amphibolites, whereas igneous rocks comprise of granites and pegmatites. Preliminary structural data obtained from the outcrops identified the regional, steep to moderately dipping foliation trend in the WNW-ESE at Byobu Rock, whereas they trend in the NW-SE direction at Gobanme Rock. Two generations of folding were identified, an earlier tight isoclinal intrafolial folds and a late regional open fold. The three deformational events identified are comparable and consistent with those reported in the neighboring outcrops in the Prince Olav Coast. Metamorphic P-T conditions estimated based on various geothermobarometries indicate that the rocks have experienced granulite grade conditions during peak metamorphism (770-880°C and 6-9kbar). The finding of orthopyroxene at Byobu Rock in this study extends the orthopyroxene-in isograd in the progressive metamorphic zone in the Lutzow-Holm Complex further eastward beyond Tenmondai Rock. Inclusions of kyanite within garnet in metapelitic rocks suggest a clockwise P-T path, consistent with the P-T paths suggested for the Lutzow-Holm Complex. Preliminary bulk rock geochemical investigations indicate that granitic rocks and quartzo-feldspathic gneiss mostly belong to volcanic arc granite suite, though their origin remains indistinct. Electron microprobe dating of monazites from representative rocks gave Pan-African ages (557±33Ma), consistent with the regional metamorphic ages reported earlier. Thus, based on the similarities on structural, petrological, geochemical and geochronological data, the Byobu Rock and Gobanme Rock are considered to be integral part of the Pan-African Lutzow-Holm Complex with analogous geological history.

Monazites in high-grade metapelites from the Lutzow-Holm Complex and Napier Complex have been examined in terms of U, Th, Pb and rare earth element (REE) chemistry using an electron microprobe. The studied samples include four granulite-facies garnet-biotite-bearing metapelites from Skallen within the Lutzow-Holm Complex, and a re-hydrated garnet-sillimanite gneiss from the Mt. Riiser-Larsen area within the UHT zone of the Napier Complex. Two out of four garnet-bearing metapelitic samples from Skallen gave simple 560-500Ma monazite U-Th-Pb ages, whereas the other two samples yielded two age populations, i.e., 560-500Ma and 650-580Ma. The younger age group is consistent with the 550-520Ma metamorphic ages reported by SHRIMP. The older>580Ma monazites are relatively enriched in Nd, Sm, Gd, Dy (MREE) and depleted in Si (Ca and Th) compared with the younger (560-500Ma) ones. These older monazites possibly formed through M-HREE-enriched conditions such as garnet-free conditions, suggesting that the growth of these monazites pre-dated the peak metamorphism. Garnet-sillimanite gneiss from the Mt. Riiser-Larsen area shows various post-UHT re-hydration textures such as biotite-sillimanite aggregates, and fine-grained biotite flakes around or intracrystalline fractures within garnet porphyroblasts. Monazites enclosed within garnet cores have 2480-2440Ma U-Th-Pb ages consistent with the reported zircon and monazite SHRIMP dates. On the other hand, those associated with re-hydrated zones gave fluctuating 2200-700Ma ages. These younger ages are thought to reflect the incomplete chemical disturbance during the post-UHT crustal processes.