Combined satellite- and ULS-derived sea-ice flux in the Weddell Sea, Antarctica
Combined satellite- and ULS-derived sea-ice flux in the Weddell Sea, Antarctica
复制标题
南极洲威德尔海的卫星和 ULS 综合海冰通量
作者：
M. Drinkwater;Xiang Liu;Sabine Harms
摘要几年来每天微波卫星冰漂移相结合的停泊向上看声纳（ULS）冰草案到一个冰体积通量记录点沿着横跨威德尔海，南极洲的通量门。月冰输运在系泊位置变化，从Joinville岛附近的最大输出0.4 m3 s-1到沿Fimbul和Riiser-Larsen冰架边缘沿着输入的-0.4 m3 s-1。在通量门的每一端都观察到冬季峰值，在那里，高浓度的变形冰沿着海岸线平流进出盆地。相比之下，中央环流的季节性可以忽略不计，输送量要小得多。在ULS重叠运行期间，环流中心以西的月平均综合冰输出量为59 × 103 m3 s-1，东风漂移的输入量为-17 × 103 m3 s-1。ULS数据与ERS卫星观测的雷达后向散射进行了比较，以获得冰厚与后向散射随入射角变化率之间的经验关系。由此产生的代理冰厚度数据与特殊传感器微波/成像仪导出的冰速度相结合，以获得1992 - 1998年期间净冰体积通量的季节性变化估计值。显着的年际变化，观察冰体积通量表示为淡水运输。1992年观测到的年平均最大值为0.054 Sv; 1996年观测到的年平均最小值为0.015 Sv。观察到6年平均运输量为0.032 Sv。季节性冰出口量最大值出现在1992年7月，最小值出现在1996年11月。10年平均面积通量为30 × 103 m2 s-1，净体积通量的年际变化与面积通量的年际变化密切相关，夏季最小值出现在1990/91和1996/97.最大面积输送发生在1991年，虽然这早于ERS-1散射计的数据，但Harms和其他人对冰厚的估计证实1991年是净综合淡水输送的十年高峰。
Abstract Several years of daily microwave satellite ice drift are combined with moored upward-looking sonar (ULS) ice drafts into an ice-volume flux record at points along a flux gate across the Weddell Sea, Antarctica. Monthly ice transport varies at the mooring locations from a maximum export of 0.4 m3 s−1 near joinville Island to −0.4 m3 s−1 imported along the Fimbul and Riiser-Larsen ice-shelf margins. Winter peaks are observed at each end of the flux gate, where high concentrations of deformed ice are advected in and out of the basin along the coastline. The central gyre, in contrast, exhibits negligible seasonality and much smaller volume transports. During the period of overlapping ULS operation, the mean monthly integrated ice export west of the gyre center is 59 × 103 m3 s−1, and the import in the East Wind Drift is −17 x103 m3 s -1. ULS data are compared with ERS satellite observation of radar backscatter to obtain an empirical relationship between ice thickness and the rate of change of backscatter with incidence angle. Resulting proxy ice-thickness data are combined with Special Sensor Microwave/Imager-derived ice velocities to obtain seasonally varying estimates of net ice-volume flux for the period 1992−98. Significant interannual variability is observed in ice-volume flux expressed as fresh-water transport. A maximum annual mean of 0.054 Sv is observed in 1992; with a minimum of 0.015 Sv in 1996. A 6 year mean transport of 0.032 Sv is observed. Maximum seasonal ice export occurs in July 1992, with a minimum in November 1996. The 10 year mean area flux is 30 × 103 m2 s –1 Interannual variations in net volume flux closely follow variations in area flux, with summer minima in 1990/91 and 1996/97. Maximum area transport occurs in 1991, and although this predates the ERS-1 scatterometer data, ice-thickness estimates by Harms and others confirm 1991 as a decadal peak in net integrated fresh-water transport.