Improvement in Track and Intensity Prediction of Indian Seas Tropical Cyclones with Vortex Assimilation - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 221

4.2 Improvement in Intensity Prediction
The intensity prediction is analysed in terms of minimum central sea level
pressure (CSLP; hPa) and maximum sustainable wind (MSW, ms -1 ). In case of
Aila, the best-fit minimum CSLP of 968 hPa and MSW of 31 ms -1 were
observed. Similarly, the minimum CSLP of 920 hPa with MSW of 65 ms -1
were observed for Gonu.
The marginal improvement is seen in the intensity prediction for both the
tropical cyclones Aila and Gonu (Figures not shown). Figure 4 represents the
spatial distribution of minimum central sea level pressure (hPa) for cyclone
Aila as simulated from the initial condition of 12 UTC 23 May 2009 (all cases
not shown) with CNTL and DA experiments. Figure 4 (a-c) corresponds to the
initial, 24 hr and 48 hr forecast with the CNTL simulation and Figure 4 (d-f)
represents the corresponding time forecast with DA experiments respectively.
At the initial time of the model integration, the intensity prediction does not
show much improvement whereas significant improvement is noticed in the
subsequent forecast hour. With the initial condition of 12 UTC 23 May 2009,
the model could simulate the minimum CSLP of 970 hPa and 968 hPa with
CNTL and DA experiments, respectively. But, the spatial distribution does not
provide such information. So, in order to estimate the error associated with the
intensity forecast, we have evaluated the CSLP and MSW error in both CNTL
and DA experiments and presented in Fig. 5. Similar to Fig. 2, the landfall
time with different initial conditions are highlighted through oval shape. It is
Fig. 4: Minimum central sea level pressure (hPa) as simulated from the initial condition
of 12 UTC 23 May 2009 (Aila cyclone) with CNTL and DA experiments.