1. The objective standard for Asian Dust determination using the instrument in the Republic of Korea SEONG-HEON KIM, HYUK-JE LEE, JAE-YOUNG KIM Observational Technology and Management Division, Korea Meteorological Administration E-mail : shkim@kma.go.kr Asian Dust Monitoring Network Instrument Future Plan  PM10  Recently Global Warming and Industrialization makes rapid progress of the desertification in East Asia.  The intensity and occurrence of Asian dust have gradually increased since 2000 in Korea.  A severe Asian dust event was observed 2-3 times per year in 2000s and affecting public health and industry.  KMA built quantitative Asian Dust Monitoring Network for preventing damage from Asian dust and established Warning System for Asian dust in 2002. Reference Young-Gon Lee and C.-H. Cho, 2007 : Characteristics of Aerosol Size Distribution for a Severe Asian Dust Event Observed at Anmyeon, Korea in April 2006. Journal of the Korean Meteorological Society, 43, 87-96. Asian Dust Monitoring Network  LIDAR KMA LIDAR system Time series of extinction coefficient and depolarization ratio displayed in the KMA intranet Warning System  Alarm - Alarm is issued when an hourly averaged dust concentration(PM10) is expected to exceed 300 ㎍ / ㎥ for over 2 hours  Advisory - Advisory is issued when an hourly averaged dust concentration(PM10) is expected to exceed 400 ㎍ / ㎥ for over 2 hours  Warning - Warning is issued when an hourly averaged dust concentration(PM10) is expected to exceed 800 ㎍ / ㎥ for over 2 hours Objective standard for Asian Dust  KMA is using PM10 and LIDAR for observing the quantitative Asian dust, but the Asian dust is being determined from measuring with observer eyes. Hence, there is a difference of observer opinion and shortage of objectivity.  Especially, it is need to improve the determination criterion of Asian dust observation using the instruments in the case of weak Asian dust.  Background  The present situation  Asia dust is measured with the eye when PM10 concentration is less than 300 ㎍ / ㎥. - Asian dust is determined from the brown dust and sky muddiness measured with the observer eyes. Baengnyeongdo Ganghwa Gwanaksan Bukgyegryelbido Gwangdeoksan Anmyundo Chuncheon Gunsan Cheonan Cheongwon Chupungnyeong Jinju Daegu Andong Yeongdeok Yeongwol Ulleungdo Daegwallyeong Sokcho Gudeoksan Gosan Heuksando Gwangju Munsan Seoul Cheonju Suwon Ulsan Jindo PM10 station : 28 Lidar station : 4  Asian Dust determination of weak Asian Dust (less than 300 ㎍ / ㎥ )  Monitoring Asian dust - Using statistics to distinguish between Asian dust and other dust events  Asian dust determination - Asian dust is determined through observed APS(Aerodynamic Particle Sizer) as PM10 concentration is more than statistics. Local Station month BaengnyeongDoKanghwaKwangdukKwanak 1130170110170 2140170110160 3 180170 4150 140160 5150160130160 690130120170 [㎍/㎥][㎍/㎥] Table for statistic analysis (example) Asian DustNon-Asian Dust Volume Concentration change Increasing the volume concentration of the coarse particle (more than 1.5 ㎛ ) Increasing the volume concentration of the fine particle (less than 1.5 ㎛ ) Volume Concentration Distribution High volume concentration (more than 100 ㎛ 3 / ㎝ 3 ) around 2~5 ㎛ High volume concentration (more than 100 ㎛ 3 / ㎝ 3 ) less than 1 ㎛ Volume Concentration Max. Peak around 3 ㎛ Peak less than 1 ㎛ Criteria by using APS Type-1(Asian Dust) Time series of PM10 data displayed in the KMA intranet KMA PM10 system  The Instrument measuring the number density of particles with the diameter of 10 ㎛ or less  KMA is using PM10 because the diameter of Asian dust particles is mainly 2~6 ㎛.  The observed data is collected every 5 minutes, instantly displayed on Combined Meteorological Information System(COMIS), and used in quantitative Asian dust forecast.  Dual-polarization LIDAR system including polarization analyzer can get the information about the shape and vertical profile of aerosol particles since it observe depolarization and extinction coefficient though the analysis of lager pulse(532nm) holding specific polarization in atmosphere.  Generally, polarization is easily broken in non-globular shaped particles. Therefore, Asian dust observation based on depolarization is useful because aerosol like Asian dust is a not-globular shape.  The observed data is collected every 15 minutes, instantly displayed in Combined Meteorological Information System(COMIS), and used in quantitative Asian dust forecast. Type-2(Asian Dust & Pollution) Type-3(Pollution) Type-4(Sea Fog or Haze)  Studying the objective standard for Asian Dust determination by using the instrument  Applying to forecasting the weak Asian Dust