Variability and sensitivity of stability indices at Kototabang (West Sumatera, Indonesia). Issue 1 (September 2020) - Juaeni, I
Abstract: Stability index data obtained from the Radiosonde launch at the Space and Atmospheric Observation Station Agam District (West Sumatera-Indonesia) in 30 August to 2 September 2016 (three times launches a day), 5 March to 9 March 2018 (twice launches a day) and 29 April to 2 May 2019 (once launch a day) used Vaisala RS41-SG. The purpose of this study was to investigate the stability indices variations and finding the best indicators for convective disturbances at Kototabang in the tropical region. The stability indices studied were CINH, CAPE, K-index, Ko-index, S-index, SI, LI, TT-index, and the values of temperature, pressure, and height of the stability layers (LCL, LFC, CCL, and EL). K-index, S-index, and TT-index indicated that atmospheric conditions were always unstable. The indices fluctuated slightly as well as temperatures and pressures at stability level. While CAPE, Ko-Index, LI, SI, CINH, temperature and pressure of EL, and the elevations of LCL, LFC, CCL, El were very fluctuating and showed clearly the stable and unstable conditions. Three different observation periods produced three sets of characters for each index. Based on variability analysis and two assessment derived CAPE, CINH, SI and EL-Z can be used as the rainfall predictors.