Desarrollo de la Antártica

Takesi Nagata I THE ADVANCEMENT OF SCIENTIFIC RESEARCH ••• c) Gmvity D~str¡~buti.on The measurements of gravity have been made at more than 6,000 points along various Antarctic inland traverse routes to date. These gravity data have been utilized for determining the bed rack topo– graphy in Antarctica. From tlhe observed gravity anomalies, the thickness of "\Test Antarctic curst has been evaluated to be 25 '-' 35 km, w,hich is in approximate agreement with the result obtained from the seismic surface wave dispersion. The international gravity reference point in Antarctica is located at 69QOO'3 S in latitude and 39935' E in longitude (Syowa Station). The standard gravity value at the reference point of 14. O m in elevation is 982.52630 gals. The gravity chart over Antarctica is now being compiled by the soviet group of SCAR geophysicists and will be soon published by the USSR Academy of ScÍences. d) Geomagnetic Field The geomagnetic field distribution in Antarctica :has been fairly well measured along various traverse routes. iln addition, the satellite– borne magnetic surveys carried out in connectíon with the World Magnetic Survey (WMS) program (Caín and Langel, 1971) :llave sup– plied an almost complete continuous distribution of the geomagnetic fieId over Antarctica. Thus, the International Geomagnetic Reference Field (IGRF) sufficiently covers the Antarctic region. The South mag– netic pole (where the horizontal magnetic force is zero and therefore the magnetic dip angle becomes 90°) is Iocated at present at a point of 67,I'°S and 142.7°E where is close to Dumont d'IUrvifle station. The Antarctic magpetíc charts based on tlhe latest available data are now being compiled by Japanese group of SCAR geophysicists and will be 500n published. Some important results Ihave been derived from the airboTne mag– netic surveys over spedal areas in Antarctica, particularly the vicinity of Mirny station and the neighbourhood of Dufek massif (e.g. Atlas Antarktiki, 1'966). lIt seems that large magnetic anomalies found in these areas suggest the presence of iron-rich ores. § 9. UPPER AnWSPHERE 'P'HYSICS IN At'lTARCTICA Since the time of IGY period, the upper atmosphere physics re¡,earch has been one of the best organized sdentific Pr<lIoOTaIDS in Antarctica. Up to the IGY period, scientific researches of rhe polar upper atmos– phere phenomena including auroral displays had been promoted