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Does Asian dust play a role as CCN?

Does Asian dust play a role as CCN?. Gill-Ran Jeong, Lance Giles, Matthew Widlansky. Group proposal Aerosol, Cloud, and Climate ( EAS 8802) April 24 th , 2006. O 3 , S O 2 , NO 2 , HNO 3. 1. Motivation: Introduction of a problem.

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Does Asian dust play a role as CCN?

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  1. Does Asian dust play a role as CCN? Gill-Ran Jeong, Lance Giles, Matthew Widlansky Group proposal Aerosol, Cloud, and Climate ( EAS 8802) April 24th, 2006 O3, SO2,NO2, HNO3

  2. 1. Motivation: Introduction of a problem The microphysical and chemical properties of aged mineral dust as a candidate of CCN  sulfate coating in the dust fine mode can become a CCN Controlling factors to CCN 1.Size 2.Composition (Hygroscopic property) Japan spring 2004 (Matsumoto et al., GRL 2006) 1: dust-laden cloud 2: dust-free cloud 3:smoke in dust ACE-Asia spring 2001 (Clarke et al., JGR 2004) Tailland, spring 1998 (Rosenfeld et al., PNAS 2001)

  3. 1. Motivation: Importance of complexity • The limitation of current understanding • Lack of long term dust record downwind of Asian outflow. • Ability to discriminate clouds from dust in current satellite images. • Measurements of CCN during dust and non-dust periods. • 1.Why do we need to do another field experiment in East Asia region? • New A-train land-ocean satellite coverage (launched yesterday) • i) Overcoming of cloud contamination in dust detection • ii) Three dimensional measurement of cloud structure • In addition, aircraft and ground-base measurement • The temporal and spatial resolution of instrumental measurement and are they consistent? • 2. What do we want to see? • During dust and non-dust period: • Vertical profiles of the CCN, clouds, water vapor • Time required for a dust CCN to grow into cloud droplets. • iii) Size resolved chemical composition

  4. 2. Objectives and goals 1. Analyze the previous data on dust, clouds, and precipitation in order to find any relation between dust. clouds and precipitation. 2. Investigate satellite observations pertaining to dust, clouds and precipitation with the same temporal and spatial resolution. (Cloudsat, MODIS and CALIPSO) • Investigate data from airborne and ground-base measurements of dust size • distribution, chemical composition, and pH of precipitation. 4. Compare individual instrumental measurements to map 3-D dust and precipitable water distributions. Goals • Find what roles Asian dust play as CCN? • Investigate effects of mineral dust on the aerosol-cloud-climate system.

  5. 3. Strategy Space 120ºE ~ 150ºE, 20ºN ~ 40ºN Time Spring, 2007 (March, April) Preliminary study Data analysis Visibility, cloud and precipitation from surface meteorological data, ISCCP, GPCP A suit of Measurement Validation of observation Cloud and CCN Precipitation Dust (satellite) Dust (ground-base) 3-D Cloud, CCN distribution Expected results Proof of dust-induced CCN Time series 3-D Dust distribution Dust size radius Time series Fraction of chemical composition Contribution to understanding Climate system Dust – Cloud – Climate

  6. 4. Experimental instruments Measured Quantity Instrument Past long-term dust concentration Surface observation of visibility monthly mean precipitation GPCP 3-hour average cloud ISCCP Cloud profile Liquid and ice contents CloudSat Rain drop and precipitation Aerosol profile CALIPSO(CALIOP) Cloud profile Optical depth of thin cirrus cloud Aerosol optical depth MODIS Particle size TOA radiation budget CERES Dust size distribution OPC IMPACTOR electron and optical microscopy Dust chemical compositions Aerosol mass spectrometer

  7. 4. Experimental Instruments MODIS CloudSat CALIPSO • - Variable resolutions range: - 94-GHz nadir-looking radar measures backscatter - Active lidar instrument (CALIOP) with passive infrared (IIR) and visible imagers (WFC) to probe the vertical structure and properties of thin clouds • 250m (bands 1-2) • 500m (bands 3-7) • 1000m (bands 8-36) • Measure profiles of cloud optical properties • Measure cloud liquid and ice water content • Profile the vertical structure of clouds • (500m vertical resolution) • Will distinguish between cloud condensate (cloud particles) and precipitation • Swath width of 2330km - Cloud and Aerosol products by MODIS: - Polarization-sensitive lidar • Cloud and aerosol optical depths • Particle size information • Cloud-top height • Cloud emissivity - Measures the 1064nm backscatter intensity and the polarized 532nm backscattered signal Sample of Aerosol Optical Depth Measurements:

  8. 5. A contribution to understanding aerosol-cloud-climate Asian dust may suppress or enhance precipitationoutflow of Asian dust region. positive or negative (?) Asian dust Cloud and precipitation negative Hydrological cycle in Asian region (negative or positive feedback) Dust properties Direct impact Indirect impact Radiative radiative forcing at TOA radiative forcing at the sfc heating/cooling actinic flux heterogeneous chemistry on dust surface photolysis Chemical

  9. 5. A contribution to understanding aerosol-cloud-climate Asian dust may suppress or enhance precipitationoutflow of Asian dust region. positive or negative (?) Asian dust Cloud and precipitation negative Hydrological cycle in Asian region (negative or positive feedback) Dust properties Direct impact Indirect impact Radiative radiative forcing at TOA radiative forcing at the sfc heating/cooling actinic flux cloud properties heterogeneous chemistry on dust surface photolysis Chemical CCN Hygroscopic

  10. 5. A contribution to understanding aerosol-cloud-climate

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