Abstract

In this study interior plus Surface Quasi-Geostrophic (isQG) methodology is used to reconstruct subsurface density anomaly using sea surface temperature (SST), sea surface salinity (SSS) and sea surface height (SSH). The study is carried out in the Arabian Sea and Bay of Bengal of the Northern Indian ocean region. isQG is first tested for identical twin experiments, where the surface data and the stability profile (N²) were taken from a numerical ocean model. The root mean square error (RMSE) between isQG and model density anomalies lie within the error bars of model density anomaly in most of the levels. The impact of expected errors in synthetic observations of SST and SSS on isQG retrieved density anomalies was studied and it is found that error in SSS results in greater RMSE in isQG density anomaly profile in the Arabian sea than in the Bay of Bengal. isQG method is then applied to the satellite observations of SST, SSS and SSH and retrieved density profiles are then compared with model outputs and in-situ observations from RAMA buoy for the year 2019. The comparison indicates seasonal dependency and effect of N² on the performance of isQG method.

摘要

在这项研究中，内部加表面准地转 (isQG) 方法用于使用海面温度 (SST)、海面盐度 (SSS) 和海面高度 (SSH) 重建地下密度异常。该研究在北印度洋地区的阿拉伯海和孟加拉湾进行。isQG 首先针对相同的孪生实验进行测试，其中表面数据和稳定性分布 (N ²) 取自数值海洋模型。isQG 和模型密度异常之间的均方根误差 (RMSE) 在大多数级别都位于模型密度异常的误差条内。研究了 SST 和 SSS 综合观测中的预期误差对 isQG 反演密度异常的影响，发现 SSS 中的误差导致阿拉伯海 isQG 密度异常剖面的 RMSE 大于孟加拉湾。然后将 isQG 方法应用于 SST、SSS 和 SSH 的卫星观测，然后将反演的密度剖面与 2019 年的模型输出和 RAMA 浮标的原位观测进行比较。该比较表明 N ²对isQG 方法的性能。