杭州湾地波雷达观测的海流数据取样率分析  

Hangzhouwan Bay CODAR observation and the current sampling rate analysis

作　　者：董如洲[1] 魏泉苗[2] 徐小弟[2] 陈琪[1] 梁楚进[1] 

机构地区：[1]国家海洋局第二海洋研究所,浙江杭州310012 [2]国家海洋局东海分局东海海洋预报中心,上海200081

出　　处：《海洋学研究》2008年第4期55-60,共6页Journal of Marine Sciences

摘　　要：根据杭州湾口区两台地波雷达5个半月观测的资料,对其中的3 189个有效观测时次的海流数据取样率(CSR)在空间和时间上的变化规律进行了分析,结果表明,在两台雷达波交叉观测的中心区域各测点的地波雷达观测的海流数据取样率高于外围区域,在中心区域海流数据取样率可达98%以上,向外围区域海流数据取样率逐渐平缓递减,到边缘区域海流数据取样率仅在20%以下;地波雷达观测的海流数据取样率有明显的日变化,白天海流数据取样率明显低于夜间;17时海流数据平均取样率达到最低值(约49%),然后很快上升,至02时达最高值(约74%),然后再缓慢下降至17时为止。同时在10时和20时地波雷达观测的海流数据取样率呈现两个相对低值点,可能与人们在这两个时段通讯繁忙所造成的干扰有一定的关系。海流流速对地波雷达观测的海流数据取样率也有较大影响,呈负相关,流速大时海流数据取样率比流速小时的要低,在海流数据取样率大于98%的中心区域,流速和海流数据取样率的相关系数小于-0.8,在海流数据取样率大于60%的区域,流速和海流数据取样率的相关系数小于-0.6,体现明显的相互关联。地波雷达观测的海流数据取样率和潮汐有着每日4次的良好相干,而似乎和风没有显著的关系。希望这些分析对地波雷达以后的推广使用能积累一些经验和参考意见。Based on five months and a half CODAR data with 3 189 effective hours of observation in the Hangzhouwan Bay, the operational status of the device and the temporal and spatial variation of the current sampling rate are analyzed and discussed. The observation area about 1 500 square kilometer is a rectangle in shape in which there are 177 effective observation points that are 3 km apart from each other both longitudinally and latitudinally. The sampling rate is the result of the number of points with effective data at a time point divided by the total observation points 177 and multiplied by 100. The time series consisted of all the sampling rates at every time points is the main point discussed here, which is still named sampling rate. The analysis shows that the sampling rate at the central area covered by the wave beam of the two CODARs is up to more than 98% and higher than those of surrounding area. At the edge of the observation area the sampling rate is less than 20%. CSR also has obvious time difference. It is high at daytime and low at night evidently. Averagely it reaches its minimum about 49% at 17.00, then rises quickly to the maximum about 74% at 02：00. And then it slowly decreases to its minimum 17：00 again. This process is unsymmetrical. It rises rapidly from 17：00 to 02：00 with nine hours and decreases slowly from 02：00 to 17：00 with fifteen hours. And there are two comparatively low points at 10：00 and 20：00, which may be caused by people＇s busy radio communication at that time. The current speed has considerable influence on CSR. They submit a negative correlation. The CSR is high while current speed is slow and low while current speed is high. The correlation coefficient is less than -80% in the central area where CSR is above 98%. The correlation coefficient is less than -60% in the area where the CSR is above 60%. As for the question about how high passing through the area. But the CSR showed no significant change while the wind speed changed greatly. It is said that seawater

关 键 词：地波雷达 海流数据取样率 相关系数 相干函数 杭州湾 

分 类 号：P731.21[天文地球—海洋科学] TN959[电子电信—信号与信息处理]