Validation of a global reanalysis model in representing synoptic-scale eddies using scatterometer data: A case study

A synoptic-scale cyclonic eddy was captured in the National Centers for Environmental Prediction (NCEP) global reanalysis surface winds in the Bay of Bengal and the Arabian Sea in October 1996. The eddy was formed in the Bay of Bengal in the middle of October 1996. It migrated across southern India, entered the Arabian Sea, and moved along the west coast of India before it turned and propagated across the Arabian Sea toward the Somali coast. The eddy eventually dissipated near Socotra in early November. The performance of the model winds is validated using the National Aeronautics and Space Administration Scatterometer (NSCAT) data along swath measurements. The model is able to resolve the eddy. The results compare well with observations in circulation intensity but differ in eddy center locations and, therefore, in westward propagation speeds in the late stage of the eddy life cycle.