92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Wednesday, 25 January 2012
Recent Results in the Cloud Seeding Experiments in the Mountainous Area in Korea
Room 244 (New Orleans Convention Center )
Chulkyu Lee, National Institute of Meteorological Research, Korea Meteorological Administration, Seoul, South Korea; and J. W. Jung, J. Y. Jeong, H. Y. Yang, J. Y. Bae, S. K. Seo, K. H. Chang, J. W. Cha, and Y. J. Choi

Weather modification has been carried out in the airborne cloud seeding and fog dissipation in Korea by National Institute of Meteorological Research (NIMR). Drought frequently takes place in Korea in spring. There were feasibility studies on the cloud seeding before 2008. Since that, the cloud seeding experiments have substantially been conducted in the airborne and ground-based methods in orographic clouds to enhance precipitation. The seeding experiments were designed, based on the contact freezing and/or hygroscopic processes, assuming that seeding material was transferred by the air flow. To validate the effects such as enhanced snowfall or rainfall on the ground, the data from KMA operational weather radars and AWS as well as Micro Rain Radar and PARSIVEL disdrometer installed at the targeted areas was analyzed qualitatively and quantitatively. The airborne experiments use Cessna 206 equipped with the microwave (Ka-band) radar as well as weather modification devices. An airborne 35 GHz Ka-band radar is employed to detect development of cloud droplets through the cloud seeding by using the physical variation of its reflectivity signals, verifying the effect of the cloud seeding. We use the seeding flares of AgI for cold clouds and CaCl2 for warm clouds. The airborne experiments are mostly done in the orographic clouds at the mountainous area in Korea in cold seasons (i.e., winter and early spring), reflecting lower uncertainties in winter as guided by WMO. We have made the 20 airborne experiments for last three years, and detected 7 precipitations by the snow depth meter or rain gauge on the ground; six in the AgI seeding and one in the CaCl2 seeding. The ground-based cloud seeding experiments are mostly done in the orographic clouds (or fog) with high humidity on the Daegwallyeong Plateau (842 m above sea level) in the mountainous area in the cold seasons since 2005. We make experiments by combusting AgINH4 solution with two seeding rates, CR1 = 0.63 AgI g/min and CR2 = 1.24 AgI g/min. The snowfall increments are mostly found in the CR1 seeding in clouds with cloud droplets of >8 mm in diameter.

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