Seasonal variations in oxygen isotope ratios of daily collected precipitation and wind drift samples and in the final snow cover at Dome Fuji Station, Antarctica
Seasonal variations in oxygen isotope ratios of daily collected precipitation and wind drift samples and in the final snow cover at Dome Fuji Station, Antarctica
复制标题
DOI：
10.1029/2004jd004953
复制
发表时间：
2005-06
影响因子：
--
通讯作者：
H. Motoyama;N. Hirasawa;K. Satow;O. Watanabe
中科院分区：
文献类型：
--
作者：
H. Motoyama;N. Hirasawa;K. Satow;O. Watanabe
[1] 1997年2月至1998年1月，在距离最近的海岸约1000公里的Dome Fuji站（77.19°S, 39.42°E，海拔3810米）采集了新鲜降雪、漂流雪和地表雪样本。所有收集的样品都在东京国立极地研究所（NIPR）进行了δ18O分析。边界层（TBL）顶部温度每周至少测量两次。正如预期的那样，所有收集到的样本都表现出季节变化，夏季值较高，冬季值较低。然而，发现不同种类的样品与表面空气温度（Ta）的关系是不同的。在采样年内，使用经典方法测量的地表气温比平均地表温度Ts（定义为10 m深度的第一层温度）高出约3℃。导致新沉积的雪和表面雪层之间差异的一个重要过程是冬季空气水分的升华。近年来，在用gcm解释极地δ2H和δ18O分布模式方面取得了显著进展。在Dome Fuji站的详细观测表明，改进的Rayleigh型模式只能部分解释个别降雪的δ18O值，并且雪沉积后的过程也必须考虑在内。
[1] Freshly fallen snow, drifting snow, and surface snow samples were collected between February 1997 and January 1998 at the Dome Fuji Station (77.19°S, 39.42°E, 3,810 meters above sea level (MASL)) located approximately 1000 km from the nearest coast. All the collected samples were analyzed for δ18O at the National Institute of Polar Research (NIPR) at Tokyo. The temperature at the top of the boundary layer (TBL) was measured at least twice a week. As expected, all collected samples show seasonal variations with higher values in summer and lower values in winter. However, the relationship with the surface air temperature (Ta) was found to be different for each species of samples. During the sampling year, the surface air temperature, which was measured using the classical methods, was found to be about 3°C higher than the mean surface temperature Ts, defined as the firn layer temperature at 10 m depth. One important process that leads to differences between the freshly deposited snow and the surface firn layer is the sublimation of air moisture during the winter months. Remarkable progress has recently been made to explain the δ2H and δ18O distribution patterns for Polar Regions with GCMs. Detailed observations at the Dome Fuji station reveal that δ18O values for the individual snowfalls are only partly explained by the improved Rayleigh type models, and that the processes after snow deposition also have to be taken into account.