Role of Sea Surface Temperature in Simulation of Arabian Sea Cyclone - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 344

from NCEP/NCAR reanalysis are used to provide surface and boundary
conditions to the model.
In the present section, we discuss about the changes in intensity due to
changes in the SST owing to projected warming of SST. The cyclone intensity
from initial to landfall for CSST and PSST experiments have been computed
and shown in Table 3. It is seen from the table that the intensity of the cyclone
is same in both the experiments till day-1. The rate of intensity in PSST is
becoming more than CSST from day-2. From day-1 to day-2, the central
pressure drop (CPD) in CSST is 10 hPa, while it is 11 hPa in PSST. From day-
2 to day-3, the CPD is about 18 hPa in CSST, whereas it is 34 hPa in PSST
which indicates around 46% increase in CPD at intense stage of the cyclone
during future warming era. When the cyclone reaches close to the landfall i.e.
on day-4, the CPD is about 22 hPa in CSST and 44 hPa in PSST. This indicates
that the increase in intensity will be more at the peak intense stage (~100%)
than other stage of the cyclone. This indicates that the cyclone will be more
severe in the warming era and the strength of the cyclone will be higher at the
peak intense stage. The result suggests that the intensity of the cyclone may
increase on an average 10% to 50% during future warm SST conditions.

Table 3: Cyclone intensity in terms of central pressure (hPa)

00 UTC of forecast JTWC Current SST Projected SST

day (date) (SST from 27-33 °C) (SST from 29-33 °C)

Initial (06.05.2002) 1002 1003 1003

Day-1 (07.05.2002) 994 1003 1003

Day-2 (08.05.2002) 997 1000 999

Day-3 (09.05.2002) 994 992 976

Day-4 (10.05.2002) 991 988 966

4. Conclusions

To examine the sensitivity of SST and its gradient on tropical cyclone track
and intensity, two sets of experiments are conducted with different SST over
Arabian Sea. In the first set, the influence of different SST and its gradient in
simulation of cyclone track and intensity has been studied. For this four different
SSTs are used namely (i) same as NCEP skin temperature (Control), (ii)
generated no gradient SST in which the value of SST is constant (=27°C)
throughout the Arabian Sea (same SST), (iii) SST gradient has been incorporated
virtually over some places (where the positive SSHA are present) in experiment
(ii) (Inserted SST grad), and (iv) SST is converted from SSHA keeping the
gradient same (SSHA2SST). In the second set, two different SSTs are generated
from SSHA in which the ranges of SST is kept 27-33°C for the first experiment
(CSST) and 29-33°C in the second experiment (PSST). The broad conclusions
of the present study are given below.