Ocean response to Tropical Cyclone Vayu
- Poster presented during WCSSP 3 - IBF Workshop held at IITM Pune 29-30 Nov 2019.
- You can grab a PDF copy of the poster here.
A very severe cyclonic storm Vayu which is unique in many aspects originated near the southeast Arabian sea with multiple curvatures on 10-June-2019 and made landfall on 17-June-2019. We have simulated the storm using a coupled ocean-atmosphere model. The coupled system has its ocean component as Indian Ocean HYCOM setup at INCOIS and WRF-NMM core as the atmospheric part. Cyclone induced cooling was prominent along the westward recurved path and a maximum cooling of 3.5 °C was observed. Spatial extent and magnitude of model-simulated SST cooling agreed well with satellite observations. During the initial northward movement of the storm, it closely followed the shelf break till it made the first curvature. During this period, warm water (>28 °C) was present along the west coast of India for the entire depth of water column. Thus, warm water on the right side of the cyclone track suppressed the SST cooling before the first curvature. A right-ward bias in maximum mixed layer depth (MLD) is evident in the model simulation, which confirms that wind mixing of the whole water column near the coast. However, the lack of a vertical thermal gradient caused poor surface cooling expected due to entrainment. A shallow mixed layer (MLD<40m) and a low TCHP (<60 kJ/cm^2) might have contributed to the weakening of the storm after the first curvature.
- The inner two nests follows the storm.
- Note that every 10th grid point in x and y direction is plotted here for clarity.
- The following nest movement is from the cycle initialized at 2019-06-11 00UTC.
The following output is compiled by aggregating all 6-hr forecast from each cycle.
