亚太地区空间地球动力学研究计划(APSG)首期VLBI联测结果

1997年 1 0月中国科学院上海天文台与美国宇航局Goddard空间飞行中心(GSFC)成功组织实施了亚太地区空间地球动力学研究计划 (APSG)首期联测中的VLBI观测 .共 6个VLBI站参加 ,包括中国上海和乌鲁木齐站、美国阿拉斯加Gilcreek站和夏威夷Kokee站、日本鹿岛 (Kashima)站及澳大利亚塔斯玛尼亚的Hobart站 .各站之间的基线长度为 1 90 0～ 1 1 0 0 0km ,基线测量重复率约为 1 0× 1 0 ^-9.利用上述台站以往的VLBI观测 ,并结合全球VLBI观测数据进行了综合解算 ,获得了上述 6个VLBI站的基线变化率及台站的运动速率 .特别是检测到上海台和乌鲁木齐站相对于欧亚板块稳定区域分别存在向东 8mm/a和向北偏东 1 4mm/a的运动 ,这些结果直接验证了印度大陆的向北运动影响到了我国西北和东部地区的地壳运动.     

Measurements of the VLBI experiments during the first campaign of the Asian-Pacific space geodynamics (APSG) program

During the first campaign of the Asian-Pacific space geodynamics (APSG) program in October 1997, two VLBl experiments were successfully organized and coordinated by the Astrometry and Geodesy VLBl Group of Shanghai Astronomical Observatory, the Chinese Academy of Sciences, cooperated with geodetic VLBl group, GSFC, NASA, USA. Six VLBl stations participated in the experiments, including Seshan and Urumqi station of China, Gilcreek station in Alaska and Kokee station in Hawaii of USA, Kashima station of Japan and Hobart station at Tasmania of Australia. Baseline lengths are from 1 900 to 11 000 km and the mean relative uncertainty of the baseline length measurements is 1.0 x 10^-9. In addition, the rates of the baseline lengths among the six stations and their three-dimensional velocities are solved out via global analysis of the two APSG sessions and the historical observations of the six stations as well as other VLBl observations from the global observation network. These results are appreciable to the studies of the modern crustal movement in the Asian-Pacific region. Especially,an 8 mm/a eastward motion and a 14 mm/a north by northeast motion are detected respectively for Seshan and Urumqi stations relative to the stable part of the Eurasian plate. The motions directly illustrate the effect of the northward movement of Indian plate on the modern crustal motions of the northwestern and the eastern part of China, which is of important significance to the study of the modern crustal motion of China.