Mechanism of initiation and regeneration of convective cell in Bandung Basin, Indonesia

Abstract

The mechanism of convective cell initiation and regeneration in the Bandung Basin ($$107.35^\circ \text{E}-107.95^\circ \text{E};6.75^\circ \text{S}-7.25^\circ \text{S}$$ 107 . 35 ∘ E - 107 . 95 ∘ E ; 6 . 75 ∘ S - 7 . 25 ∘ S ), Indonesia, is investigated using a Weather Research and Forecasting model. Based on the Cumulative Distribution Function and Regeneration Index, model simulations were conducted using case studies in February–March 2019. Upslope wind flows to the mountain peak in north and south of the basin due to solar heating, carrying water vapor from the bottom of the basin. Therefore, low-level convergence is formed due to the convergence of winds from the bottom of the basin and from outside the basin. The low-level convergence causes the developing updraft, makes atmosphere unstable, and generates convective initiation. The convective system will be developed in the mountains region, produced precipitation, and formed cold pools on the surface. The cold pool will fall down the slopes and convective activity from the mountains will continue to the bottom of the basin. The convective system’s outflow causes the cold pool to move in the west–east direction. The cold pool will collide with warmer air from the opposite direction, resulting in an updraft at the cold pool leading edge, and convection will be re-initiated (convective regeneration) in the Bandung Basin, with the new convective system tending to move eastward.