Abstract:
A research on effect of wind direction to rainfall in Kototabang West Sumatera has been
done by analysing the second data of daily data. The data were collected by Equatorial
Atmosphere Radar (EAR) and Optical Rain Gauge (ORG) for one year (May 2014-
April 2015) which were base on the results of study. It was found that the highest
rainfall occurred in Agust 2014, namely 4,94 mm/day with different wind directions and
speed with meridional wind +0,57 m/s, vertical wind -0,02 m/s, and zonal wind -2,56
m/s. The value of rainfall was categorised high which represented rainy season. It was
supposed to be the dry season but in reality it was different because in the area of
research occurred rotation of the wind direction with high air temperatures resulting in
high evaporation that can cause high raifall. In July 2014 it was obtained the lowest
rainfall of 0,7 mm/day with the wind direction and speed were different, namely
meridional wind -0,4 m/s, vertical wind +0,02 m/s, zonal wind +3,71 m/s. Patterns of
rainfall in July 2014 showed an increase in the dry season, where high zonal wind
speed/strong destroyed the formation of convective clouds or rain-forming cloud that
caused low rainfall. Kototabang is an area that almost every month of rain, that cause
rain occured this is because the area of Kototabang is on the equator and is sourrounded
by wide sea, so that in that area, high evaporation always occures.
