Numerical Modeling of Low Level Horizontal Penetration Seeding of Supercooled Cloud with Liquid Carbon Dioxide

Sohaila Javanmard, Norihiko Fukuta, Koji Nishiyama, Yoshinori Suzuki, Kenji Wakimizu

Research output: Contribution to journalArticle

Abstract

Numerical modeling of low level horizontal penetration seeding of supercooled cloud using liquid carbon dioxide (Fukuta 1996) has been carried out for the first time. The model is time-dependent, two-dimensional, covering a region 4 km × 6 km in the x and z directions with 50 m grid intervals. We assume a supercooled cumulus cloud has already been formed and the liquid water content as constant with height. The motion of ice crystal thermal in cloud is assumed like that of cumulus cell according to Scorer (1972). The ice crystals are assumed to be spherical shape and grow by consuming supercooled cloud entrained into the ice thermal. The model shows Roll up Expansion of the Twin Horizontal Ice crystal Thermal (RETHIT) due to buoyancy. Rise of horizontal ice crystal thermal while rotating, expanding and entraining the supercooled cloud volume leads to formation of ice crystals which possess sufficiently large size and necessary fall velocity in a large cloud volume within a likely cloud lifetime at the cloud top. Creation of large crystals with fast fall velocity assures subsequent changes for effective precipitation development. The centrifugal force is also found to act on ice particles and help them spread. Optimal seeding rate of liquid carbon dioxide is assessed as about 10 gram per second.

Original languageEnglish
Pages (from-to)239-255
Number of pages17
JournalJournal of the Faculty of Agriculture, Kyushu University
Volume43
Issue number1-2
Publication statusPublished - Nov 1 1998

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Agronomy and Crop Science

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