Publication: Use and Impact of Satellite-Derived SST Data in a Global Ocean Assimilation System Over the Tropical Indian Ocean
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Date
2023
Journal Title
Journal of the Indian Society of Remote Sensing
Journal ISSN
Volume Title
Publisher
Springer
Abstract
The ocean analysis is crucial for monitoring and predicting�the ocean and also provides an initial condition to coupled atmosphere�ocean model. Due to the lack of in-situ observations, the satellite with high spatial and temporal coverage plays a vital role in improving�the data coverage as well as improving global ocean analysis. In this study, the global Nucleus European Modelling of the Ocean (NEMO)-based three-dimensional variational assimilation system called NEMOVAR is used to understand the impact of satellite-derived sea surface temperature (SST) data assimilation in the Tropical Indian Ocean (TIO). Two different experiments, such as no assimilation of satellite-derived SST called CNTR and assimilation of satellite-derived SST called EXPSST, were carried out during the winter and summer monsoon. The SST increment is much smooth for the�CNTR experiment as compared to the EXPSST experiment. The comparison of daily SST from both experiments with the Research Moored Array for African�Asian�Australian Monsoon Analysis and Prediction (RAMA) buoy observations clearly showed less RMSE and high correlation in the EXPSST experiment in the western part of the southern Indian Ocean and Arabian Sea (AS) regions during the winter monsoon. Further, the EXPSST experiment is cooler than the CNTR experiment in the Bay of Bengal (BoB) and southern Indian Ocean (10��20� S) regions for winter monsoon and AS, BoB and Equatorial Indian Ocean (EIO) regions for summer monsoon. Due to this, the EXPSST experiment lost the net heat flux (NHF) much less than the CNTR experiment. The impact of satellite-derived SST observations on the variational assimilation system through the air�sea interaction is relatively larger during summer monsoon as compared to winter monsoon. Further, it is also suggested that the impact is relatively higher in the BoB region compared to the northern AS and EIO regions extending up to 40�60�m depth during both monsoon seasons. � 2022, Indian Society of Remote Sensing.
Description
Keywords
NEMO model, Ocean data assimilation, Satellite SST, TIO