日本海西南海域现场观测和卫星高度计获取的海面高度距平的比较研究

Comparison of sea surface height anomalies derived by pressure-sensor-equipped inverted echo sounders and satellite altimetry in the Southwest Japan/East Sea

压力传感逆式回声仪(pressure-sensor-equipped inverted echo sounders,PIES)可以用来测量海底压力和声波从海底到海面的传播时间。海底压力和声波传播时间分别被用来估计水体质量变化(正压)和比容变化(斜压)对海面高度距平的贡献。对由PIES在日本海西南海域现场观测数据得到的海面高度距平(PIES SLA)与卫星高度计海面高度距平(Sat SLA)进行了比较研究。利用相关分析法,对PIES SLA和沿轨T/P卫星、沿轨ERS-2卫星测得的海面高度距平(TP SLA、ERS-2 SLA)进行了比较;对PIES SLA和AVISO网格化海面高度距平进行了比较,估计可能的误差来源,并分析PIES SLA正压部分和斜压部分对SLA的贡献。比较发现,PIES SLA和Sat SLA的相关系数较高,且均方根误差较小,并且对特定区域和特定站点产生误差可能的原因进行了进一步的探讨。通过研究,有以下结论:(1)相对于湾流和黑潮地区,这一区域正压部分对海面高度的贡献相对较大;(2)如果再考虑斜压变化对海面高度的贡献,PIES SLA和Sat SLA相关系数会有所提升;(3)在高能区PIES SLA和Sat SLA相关系数较高,符合得相对比较好。总的来说,在日本海地区,PIES SLA和Sat SLA相关系数较高,具有较高的一致性,能为我国海洋二号(HY-2)等卫星高度计的校验提供一种可靠的方式。该研究对于PIES的研发和设计以及对于PIES的布放位置的选择都有一定的借鉴意义。

Pressure-sensor-equipped inverted echo sounders （PIES） can be used to measure sea bottom pressure and the acoustic-wave propagation time from the seabed to the surface. Bottom pressure and the acoustic propagation time are used to estimate the contribution of the sea surface height anomaly （SLA） to water quality changes （positive pressure） and hema- tocrit changes （baroclinic）, respectively. In this paper, we compare SLAs derived by PIES with SLAs derived from satellite altimetry data in the Southwest Japan/East Sea. Using correlation analysis, we compared the PIES SLAs with SLAs meas- ured by the along-track T/P satellite （TP SLA） and the ERS-2 satellite （ERS-2 SLA）. We then compared the PIES SLA and AVISO gridded SLAs to estimate possible sources of error. We also analyzed the contributions of the PIES SLA positive pressure and baroclinic aspects of the SLA. The comparison results show that the correlation coefficient of the PIES SLA and Sat SLA is relatively high, and the root mean square error is relatively small. Further, we studied data from specific re- gions to identify possible causes of site-specific errors. Based on our results, we draw the following conclusions： （1） with respect to the Gulf Stream and the Kuroshio region, the contribution of positive sea surface height is relatively large; （2） if we consider the contribution of baroclinic changes in sea surface height, the PIES SLA and Sat SLA correlation coefficient will improve; （3） in the high-energy zone, the PIES SLA and Sat SLA correlation coefficient is relatively high and relatively better. Overall, in the Japan/East Sea, the PIES SLA and satellite altimeter SLA correlation coefficient is relatively high with a high level of consistency, providing a reliable way for checking the operation of Ocean II satellite （HY-2） altimeters. The research results have significance for the development and design of PIES, and for the selection of the placement of PIES.