Preliminary Study of Horizontal and Vertical Wind Profiles of Quasi-Linear Convective System over Western Java Region, Indonesia Using Weather Radar Data

One of the weather phenomenon that potentially causes extreme weather condition is the linear-shaped mesoscale convective system, including squall lines. The phenomenon that can be categorized as squall line is a convective cloud pairs with linear pattern of more than 100 km length and 6-hours lifetime. A new theory explained that cloud system with same morphology as squall line without longevity threshold can be developed on land and have significant effects. Such cloud system is so-called Quasi-Linear Convective System (QLCS), which strongly influenced by ambient dynamic processes, include horizontal and vertical wind profiles.

This research is intended as a preliminary study of horizontal and vertical wind profiles of QLCS developed over Western Java region using Doppler weather radar data from Tangerang radar site, Banten, Indonesia. The following parameters were analyzed in this research, include direction pattern and spatio-temporal significance of wind speed, divergence profile, deformation profile, vertical wind shear (VWS) direction and intensity profiles, and vertical velocity profile. Subjective and objective analysis were applied to explain the characteristics and effects of those parameters to the orientation of cloud system's propagation, relative direction and speed of the cloud system's movement and its lifetime. The results of analysis showed that the movement of the system is affected by wind direction and velocity patterns. The divergence profile combined with the vertical velocity profile representing inflow which can supply water vapor for QLCS convective cloud cluster. Furthermore, we found that the deformation profile combined with the VWS direction profile can be used to estimate QLCS propagation's orientation by 30 degrees corrections.