ANALISA ARAH ANGIN TERHADAP CURAH HUJAN MENGGUNAKAN EQUATORIAL ATMOSPHERE RADAR (EAR) DAN OPTICAL RAIN GAUGE (ORG) DI ATAS KOTOTABANG SUMATERA BARAT

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.