Monsoon squalls over Thumba during the year 1966





In this paper monsoon squall is considered as distinct from thunder squall of low wind speed and is defined as the sudden increase in wind speed to 15kt or more with less than 25° change indirection. The main features of such squalls recorded at Thumba by the electrical anemographs at three different altitudes (58,136 and 200ft)during the monsoon season of 1966 are discussed with reference to their diurnal variation, duration, speed and direction.


The monsoon squall data has been analysed and scatter diagrams of mean squall wind profiles upto 200 ft height have been constructed, The mean vertical wind shears in two different layer3 136-58 ft and 200-136 ft under squally weather conditions are described with the help of shear vector diagrams. The mean vertical shear does not exceed 5 kt/30m. Monsoon squall wind veers with height.


The wind in the layer 58-200 ft is found to obey the power law-

u/u1 = (z/z1)p


under squally weather conditions. The computed values of power index p=0.115 and the atmospheric turbulence parameter n=0.2 are described briefly.




How to Cite

V. NARAYANAN, “Monsoon squalls over Thumba during the year 1966”, MAUSAM, vol. 19, no. 4, Oct. 1968.



Shorter Contribution