Some aspects of a numerical glaciogenic artificial cloud seeding experiment using liquid carbon dioxide over kupang, Indonesia

Abstract

Artificial cloud seeding is currently being explored as a method for mitigating drought in certain regions of the Indonesian archipelago. Most ongoing projects have performed hygroscopic seeding using sodium chloride (NaCl) as the seeding agent. Although some positive effects have been observed, the statistical results of previous hygroscopic seeding experiments have generally been inconclusive. Given concerns related to the effectiveness of glaciogenic cloud seeding in tropical areas such as Indonesia, a new seeding approach must be devised from the standpoint of precipitation enhancement. As such, this study introduces a glaciogenic cloud seeding method using liquid carbon dioxide as an alternative technique. Since numerical modeling is a key component of weather modification research, this paper reports a numerical simulation conducted using the Weather Model Forecasting version 3.1.1 to investigate glaciogenic seeding experiments over the Kupang region in Indonesia’s Nusa Tenggara Province, located on the island of Timor. Simulation results indicate that the rainfall enhancement induced could be separated into two stages, the first of which concerns the direct effects of cloud seeding that enhance the intensity of rainfall from the seeded cloud. During the second stage, the interaction of the remaining cloud ice and activated convective cells under the seeded cloud that emerged after the seeding treatment enhanced precipitation in the study area by approximately 40%. The activated convective cells are thought to be strongly influenced by the sea-breeze convergence zone over Timor, indicating that the interaction of the sea-breeze convergence zone and remaining cloud ice caused by glaciogenic seeding are crucial to enhancing rainfall.