Current state of cloud seeding in Korea

Recently the airborne experiments for precipitation enhancement have been conducted in Korea using Cessna 206 equipped with the microwave (Ka-band) radar as well as weather modification devices. We have used seeding flares of AgI for cold clouds and CaCl2 for warm clouds, and validated their effects with the airborne or ground-based instruments. The precipitation enhancement experiments have been carried out in cloudy days in winter and early spring for 2008 - 2010, reflecting lower uncertainties in winter as guided by WMO. We have made 20 airborne experiments for the three years, mostly over the Taebaek mountains where orographic clouds are dominant with the easterly wind, and detected enhanced radar-reflectivity and precipitation for 7 cases in targeted areas after the seeding. However, physio-chemical and meteorological verification of the phenomena in the seeded clouds is still challenging. The experiments to be conducted hereafter have several objectives, all related to the methodology and verification. They include characterizing the resulting microphysical changes within the seeded clouds, using the appropriate airborne instruments (e.g., radar and forward scattering spectrometer probe) in the proper places at the desired times. Variables measured simultaneously for supporting these objectives include ice particle sizes and concentrations, ice nucleus concentration, and cloud liquid content as well as horizontal winds, air temperature, and stability parameters. These will result in improving the techniques in cloud seeding, and possibly help understand aerosol and cloud interactions in the atmosphere.

Acknowledgments. This work was supported by the NIMR/KMA project ‘Advanced research on industrial meteorology' and ‘Development of meteorological resources for green growth', and ‘Hydrometeorological Research in the Test-bed Region', and by National Research Foundation of Korea (NRF) grant funded by the Korea government (No. 2009-0085533).