ABSTRACT Most satellites observing sea surface winds have sun-synchronous orbits and provide observation data at the same place two times per a day. A daily mean value estimated from these data suffers from sampling errors because the high-frequency variation including a diurnal change in the wind field cannot be neglected. To overcome this problem, the use of multiple satellites is useful. The purposes of this study were to describe the time variation of the accuracy of daily mean wind data in a third-generation Japanese Ocean Flux Data Sets with Use of Remote Sensing Observations (J-OFURO3) and to investigate its causes by comparison with in situ measurement data from moored buoys. The results reveal that the three statistical measures such as bias, Root Mean Square error and cross correlation coefficient have improved over time. A set of scatter diagrams of the number of satellites versus the statistical measures for each year shows strong correlations. The accuracy of daily mean data provided by J-OFURO3 is concluded to depend on the number of satellites. We also focused on specific time intervals for satellite wind observations, particularly the maximum missing time interval (MMTI) within a day. The results showed that the correlations between the three statistical measures and MMTI were quite high. Because the above-mentioned two causes are not independent, we analysed the combined effect of the two causes together. The results show that the accuracy of daily mean data depends more strongly on MMTI than on the number of observations. By applying these results, it is possible to determine the optimal number of sensors and the optimal observation time to achieve maximum target accuracy. This provides very useful information for the design of satellite observation systems for sea surface wind.

中文翻译：

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使用多卫星传感器对日平均海面风数据精度的影响

摘要 大部分观测海面风的卫星都有太阳同步轨道，每天在同一地点提供两次观测数据。根据这些数据估计的日平均值存在采样误差，因为不能忽略包括风场昼夜变化在内的高频变化。为了克服这个问题，使用多颗卫星是有用的。本研究的目的是描述日本第三代海洋通量数据集使用遥感观测（J-OFURO3）日平均风数据精度的时间变化，并通过与原位比较来调查其原因。系泊浮标的测量数据。结果表明，随着时间的推移，偏差、均方根误差和互相关系数等三个统计指标都有所改善。一组卫星数量与每年统计量度的散点图显示出很强的相关性。J-OFURO3 提供的日平均数据的准确性被认为取决于卫星的数量。我们还关注卫星风观测的特定时间间隔，尤其是一天内的最大缺失时间间隔 (MMTI)。结果表明，三个统计量度与MMTI之间的相关性相当高。由于上述两个原因不是独立的，我们一起分析了这两个原因的综合影响。结果表明，与观察次数相比，日均数据的准确性更依赖于 MMTI。通过应用这些结果，可以确定最佳传感器数量和最佳观测时间，以实现最大目标精度。这为设计海面风卫星观测系统提供了非常有用的信息。