Cyclone and Storm Surge - Iczmpwb.org

2.13
May 126.00 7.8 4.98
June 260.10 16.0 11.55
July 358.65 22.1 15.27
August 326.14 20.1 13.55
September 243.31 15.0 12.26
October 130.60 8.0 6.38
November 51.56 3.2 2.05
December 6.09 0.4 0.50
Total 1625.09 100.0 71.0
The mean maximum and minimum temperatures are about 32°C and 15.7°C occurring in May &
January respectively. The temperature begins to rise from early February & starts falling from mid-
October. Southerly winds start blowing from the middle of March and Nor’westers make their
appearance in April and May. The humidity is about 86 percent of saturation from mid-June to mid-
October and is about 75 percent in winter.
2.4.4. Winds
Strong winds provoke two phenomena: wind set-up and wind waves. Long lasting wind, blowing in
the same direction, like the monsoon, leads to a raise of the mean sea level near the lee-side coasts,
which increases the high water levels but also the low water levels. This phenomenon is known as
wind set-up. Usually the tidal amplitudes reduce when the mean sea level rises.
The long lasting wind causes a water flow in the direction of the wind near the surface which in turn
results in a flow in the opposite direction near the bottom. This return flow near the bottom carries
sometimes significant volumes of silt towards the sea.
Another phenomenon is the wind waves. These waves develop on top of the wind set-up. They are
not only formed at sea but also in the wide sections of the network of waterways in the Sundarban
area. The height of the waves depends on the velocity of the wind, the fetch; this is the length the
wind skims over the water surface, and to a lesser extent on the water depth, assuming that the
duration of the wind is long enough to allow the waves to be fully developed.