Katabatic wind intensity and direction over Antarctica derived from scatterometer data
Katabatic wind intensity and direction over Antarctica derived from scatterometer data
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DOI：
10.1029/92gl00970
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发表时间：
1992-05
影响因子：
5.2
通讯作者：
F. Rémy;M. Ledroit;J. Minster
中科院分区：
文献类型：
--
作者：
F. Rémy;M. Ledroit;J. Minster
尽管卫星雷达散射仪最初设计用于测量海洋表面风速和风向，但它们也提供对大陆冰盖的重要观测。对南极洲部分区域的 Seasat 散射仪数据进行分析表明，信号很大程度上取决于观测的入射角，但也取决于方位角 [Ledroit 等人，1992]。反向散射系数（反向散射与入射功率之比）的最小值总是在下降风的方向上观察到。理论分析表明，后向散射系数必须对 sastrugi 坡度和方向非常敏感，sastrugi 是雪面上沿风向形成的流线型特征 [Parish 和 Bromwich，1987]。因此，卫星散射仪可以绘制萨斯特鲁吉斯的特征图，这对于解释冰盖上方的微波测量非常重要；这间接提供了这些非常持久的强风的强度和方向，这些风对南部高纬度地区的大气和海洋的行为起着重要作用。
Although satellite radar scatterometers are initially designed to measure ocean surface wind speed and direction, they also provide important observations over continental ice sheets. Data from the Seasat scatterometer analysed over a sector of Antarctica show that the signal is strongly dependent on the incidence angle of observation, but that it also depends on azimuth [Ledroit et al., 1992]. The minimum values of the backscatter coefficient (the ratio of backscattered versus incident power) are always observed in the direction of katabatic winds. A theoretical analysis shows that the backscatter coefficient must be very sensitive to the sastrugi slopes and orientations, which are streamlined features formed on the snow surface in the wind direction [Parish and Bromwich, 1987]. Satellite scatterometers can thus map the characteristics of sastrugis, of importance for the interpretation of microwave measurements above ice sheets; this indirectly provides the intensity and direction of these very persistent and strong winds, which play a important role in the behaviour of the atmosphere and ocean in high southern latitudes.