科研之友
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摘要
As the most important quantities needed in numerical modelling of sea ice dynamics, the form drag on pressure ridges and the air-ice drag coefficient are generally analysed based on wind velocities and sea-ice conditions. However, it is difficult to give exact values because these quantities have not been measured. Based on a large data set measured by a helicopter-borne laser altimeter during the Winter Weddell Outflow Study 2006, the influences of pressure-ridge morphologies and sea-ice surface roughness on the form drag of pressure ridges and the air-ice drag coefficient were considered to seek a novel strategy for analysing these two essential quantities. The results show that the contribution of form drag on pressure ridges to total air-ice drag increases at greater ridging intensity (the ratio of mean ridge height to spacing), but decreases with increasing roughness length. The air-ice drag coefficient shows a similar trend to the contribution of form drag with increasing ridging intensity. Moreover, a ridging intensity threshold was determined for the air-ice drag coefficient. These results imply that large values of the air-ice drag coefficient could be caused by form drag on pressure ridges as well as by skin drag over rough ice surfaces. Finally, the present results are consistent with reported measurements in the north-western Weddell Sea.
- 出版日期2018-6
- 单位南阳师范学院; 大连理工大学; 海岸和近海工程国家重点实验室
