Utilization of surface meteorological data, Himawari-8 satellite data, and radar data to analyze landspout in Sumenep, East Java, Indonesia (case study of 20 November 2017)

Abstract

One of the extreme weather that happened in Indonesia is landspout. Landspout is virtually a tornado that forms from a thunderstorm that is not a supercell. On November 20, 2017 at 08.00 UTC there was a landspout in the village of Kertasada, Kalianget District, Sumenep Regency of Madura, East Java, Indonesia which caused damage to dozens of houses and many shops and warehouses. The study was done to determine the differences condition of the atmosphere before, during, and after the phenomenon based on synoptic analysis, atmospheric instability analysis, satellite image analysis, and radar image analysis. The results of the synoptic analysis of two weather parameters, pressure and temperature, also supported the occurrence of landspout phenomenon. Pressure and air temperature for two days before the occurrence of the landspout had a relatively similar pattern, but the average pressure appeared higher on the day of the incident. Temperature patterns showed a decrease from one hour before the incident, which was 3.2°C. The surface wind analysis showed wind speed during the day of the incident was higher than the previous two days, with a difference of 6 m s-1. The analysis of atmospheric instability when the incidence of the Lifted-Index (LI) values indicates the ‘unstable atmosphere and possible thunderstorm criteria. K-Index (KI) shows the possible to become moderate convetive’ The total index (TT) showed a stronger convective, local lightning potential and a value were higher than the previous two days. Severe Weather Threat Index (SWEAT) showed the potential of lightweight thunderstorm with greater instability value than the previous day while the Convective Avalilable Potential Energy (CAPE) index showed a large and potentially stormy energy. Then, in this research used Himawari-8 satellite and Radar C-band to detected convective clouds. According to Satellite Animation and Interactive Diagnosis (SATAID) satellite data, there is a Cumulonimbus (cb) cloud clump in the Sumenep region of Madura, which is meant to be potentially a landspout.