Impact of horizontal resolution and the advantages of the nested domains approach in the prediction of tropical cyclone intensification and movement

The prediction of the intensification and movement of the Orissa Super Cyclone (OSC-1999) was studied using the National Center for Atmospheric Research MM5 mesoscale atmospheric model. A case study of the OSC has been chosen as it is noted to be the most intense cyclone over the Bay of Bengal of this century. Experiments were made with a single domain (1D), with two-way interactive nested two domains (2D), and with three domains (3D). The model was integrated for 5 days, and the model-predicted intensity and track positions were compared with observations. Results indicate that the enhancement of resolution produces higher intensity and does not influence the track of the storm. The nested 2D and 3D experiments produce cyclone track closely agreeing with the observations, while the 1D experiments show the deviation of the track toward north and northeast after 48 h, thus with increasing errors. Differences in the simulations with single and nested domains indicate that simulated atmospheric circulation on the eastern parts of the domain contribute to the deviation of the track in the 1D experiment and the successful simulation with 2D and 3D experiments is due to the two-way interactive approach of the nested domains.