Periodicities of palaeo-climatic records extracted from the Dome Fuji deep core

The Antarctic ice sheet preserves palaeo-climate information in the form of physical and chemical stratigraphy. A deep ice core was continuously drilled down to a depth of 2503m at Dome Fuji Station, East Dronning Maud Land, Antarctica, during the 1993-97 JARE inland operations. A time scale for the Dome Fuji core is calculated from past accumulation rates and an ice flow model. A depth-age profile was obtained for the past 320kyr back in time. The obtained palaeo-temperature profile shows the past three glacial and interglacial periods. The power spectrum for oxygen isotope variation for 320kyr shows three dominant cycles of 107kyr, 40kyr and 21kyr. Each of these three cycles is similar to Milankovitch cycles. Moving-window spectrum analysis, using a 130kyr window stepped by 10kyr over the past 320kyr, found these main cycles in every age. Variations of other chemical concentrations were also recovered from the Dome Fuji ice core, and are inversely correlated to the temperature profile. Concentrations of terrestrial and marine origin substances are high in glacial periods, and low in interglacial periods. Over the past 320kyr, the dominant periodicities of temperature were also detected in almost all chemical records

エンガン カラ ドームフジ ヘ イタル ルート ゾイ ノ コウタク セツメン ノ ブンプ トクセイ

沿岸からドームふじ基地へ至るトラバースルート沿いにおいてサスツルギ,デューン,サーマルクラックといった雪面形態の出現頻度分布の観測を行った.光沢雪面について,1992年,1999年,2002年,2003年,2004年に行われたサーマルクラックの観察結果の比較を行い,サーマルクラックが数年にわたって観察される区間があることが明らかになった.これは光沢雪面が数年間にわたって存在する場合があることを示している.Frequencies of occurrence of snow surface features such as sastrugi, dunes and thermal cracks were observed along the traverse route from the coast to Dome Fuji Station. Comparison of data on thermal cracks in 1992, 1999, 2002, 2003 and 2004 indicates that glazed surface has existed over several years

GPS ソウタイ ソクイ ニ ヨル サイキン ノ ヒガシ ナンキョク ヒョウショウ ノ シラセ リュウイキ オヨビ ドームフジ シュウヘン ノ ヒョウショウ リュウドウ カンソク

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

ナイリク エンガン チイキ (チテン H68) ノ 2002ネン カキ ノ セキセツ キショウ トクセイ

昭和基地からみずほ基地へのルート上地点H68にて,2002年夏期の積雪表面状態および気象状況について調査した.10月末に地形測量によって同地点の主風向に沿った傾斜を明らかにすると共に,積雪断面観測を行った.なお同時に設置した無人気象観測装置から約2カ月間の気象情報を取得した.気象観測結果については,対応する昭和基地のデータとともに紹介した.Snow features and meteorological conditions at H68, on the route between Syowa and Mizuho Stations, was investigated during summer 2002. The observations were carried out in late October, with the setting up of an automatic meteorological station. The snow surface features were measured to make clear the inclination along the prevailing wind direction, and snow observations were made on a vertical dug snow wall. Continuous climatic records in the following two months, obtained by the meteorological station, are introduced together with the corresponding data at Syowa Station

General tendencies of stable isotopes and major chemical constituents of the Dome Fuji deep ice core (scientific paper)

Stable isotope compositions of water and major chemical constituents of the Dome Fuji ice core are analyzed and the data sets over the entire depth of the 2503-m core are presented in appropriate time resolution as consecutive series of average value in definite terms. These results based on the first stage analyses allow a temporal climatic dividing of the three glacial-interglacial cycles present in the records. A Comparison of the climatic and environmental characteristics of these climate stages is presented