摘要
在测流过程中和资料整理时会有各种各样误差引进。但是,其中有三种误差是主要的: 1.船体的影响。铁船体本身具有磁性。它能改变海流计中磁罗经的方向,船体对表层海流流速也有影响,一般来说铁船体可使流向差的方均根值达30°～49°,流速差的方均根值达4～10厘米/秒。 2.余流是低频的流动,具有3、5、10,15天,甚至更高的变化周期。在一个定点站只观测25小时的海流资料,是得不出准确的余流值,要尽可能延长观测资料的时间序列长度。 3.用观测24小时的海流资料序列来分析余流要比用25小时海流资料序列分析余流误差大,引起最大误差可达±4%。
There are three main error sources in the process of current measurement and data analysis.
1) Ship body has a big influence upon the direction and speed of currents. Iron ship body can chang the compass direction of the current meter. The square-mean roots of the direction errors are from 30°to 49°. Ship body can also influence the speed of surface currents. The square-mean roots of speed errors are from 4 to 10cm/sec.
2) Residual current is a kind of low-frequency flow. It has 3, 5, 10, 15, day and longer periods. Observation data with 25 hours duration cannot derive correct residual current. In practice we must get as a long time series as possible.
3) Culculated residual current using 24-hours-duration data has larger error than the 25-hours-duration data. Its maximum error is about ±4% of the tidal current speed.
出处
《海洋湖沼通报》
CSCD
北大核心
1990年第2期17-23,共7页
Transactions of Oceanology and Limnology
