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Arctic Mechanisms of Interaction Between the Surface and the Atmosphere (AMISA)

Arctic Mechanisms of Interaction Between the Surface and the Atmosphere (AMISA). PI: Al Gasiewski 1 Co-PIs: Ola Persson 2 , D on Cavalieri 3 , Markus Thorsten 3 , and Michael Tjernström 4 1 Center for Environmental Technology/ Univ. of Colorado, Boulder, Colorado

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Arctic Mechanisms of Interaction Between the Surface and the Atmosphere (AMISA)

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  1. Arctic Mechanisms of Interaction Between the Surface and the Atmosphere (AMISA) PI: Al Gasiewski1 Co-PIs: Ola Persson2, Don Cavalieri3, Markus Thorsten3, and Michael Tjernström4 1Center for Environmental Technology/ Univ. of Colorado, Boulder, Colorado 2CIRES/NOAA/ESRL/PSD, Boulder, Colorado 3NASA Goddard, Greenbelt, MD 4Dept. of Meteorology, Univ. of Stockholm, Stockholm, Sweden • Other participants: • V. Leuski, D. Kraft, grad student, CET at U. of CO • B. Brooks, U. of Leeds, UK – aerosol sampling • E. Sukovich, CIRES - microphysics Funding obtained from U.S. National Aeronautics and Space Administration (NASA)

  2. NASA McDonnell-Douglas DC-8-72 research aircraft - flexible altitudes, extended range (300-14,000 m; 5400 nm) - prolonged flight duration (12 hr) - large scientific payload capability (30,000 lbs)- on-board laboratory environment Airborne measurements over/in vicinity of R/V Oden with in-situ and remote sensors on NASA DC-8. Six flights during Aug 11-29, 2008. To be based in Kiruna, Sweden Measurements focused on A. Synoptic/mesoscale structure of clouds, dynamics parameters, and surface features B. Testing and validation of satellite retrieval techniques C. In-situ sampling of cloud microphysics, aerosol species, and size distributions White area: sea ice extent 9/3/2007 Magenta line: median sea ice extent 1979-2000 (NSIDC) ASCOS Planning Meeting

  3. SCIENCE OBJECTIVES Specific Objectives 1) in-situ validation for ship, aircraft, satellite data 2) determine processes linking cloud radiative/microphysical properties to synoptic/mesoscale disturbances, boundary-layer structure, and surface energy budgets near freezeup 3) determine type and size distribution of aerosols in/near high-latitude, low-level clouds and thermal inversion 4) aircraft/satellite sea-ice imaging/mapping and atmospheric radiometric profiling 5) validate/improve NASA Aqua AMSR-E sea-ice concentration algorithm under fall transition conditions, esp. atmospheric correction 6) evaluate C-/L-band for lead/meltpond discrimination ASCOS Planning Meeting

  4. Instrumentation ASCOS Planning Meeting

  5. Instrumentation CAPS: Cloud Aerosol and Precipitation Spectrometer PSR on aircraft Aerosol sampling: Leeds airborne VACC 1. MetOne Condensation Particle Counter (CPC) - total aerosol load per ml for particles R > 3nm; Data rate 10 Hz 2. Scanning Mobility Particle Sizer (SMPS) - give number concentration for 3 nm < R < 150 nm. - spectrum generated every 2.5 min 3. Volatility System. - provides physio-chemical information about the sampled aerosol - obtain size-segregated composition of aerosol and estimate of population mixing state - volatility spectrum obtained every 10 min ASCOS Planning Meeting

  6. Mesoscale/mid-altitude track Flight Tracks Synoptic, high-altitude track Synoptic/mesoscale sampling track 1) high-level passes (10 km) on way to Oden (black dot) and mid-level (1 km) in vicinity of Oden 2) use dropsondes (D) and remote sensors for mapping and profiling Obtain 1) synoptic thermodynamic/kinematic structure of environment upwind and near Oden 2) integrated water & CLW - pseudo profile with up/down & sfc DCR 3) radiative flux divergence of low-level cloud tops Low-level track & liquid cloud penetration Low-altitude transect & liquid cloud penetration Obtain 1) particle size distributions of liquid drops/cloud ice, CLW -CAPS 2) integrated water & CLW - pseudo profile with up/down & sfc DCR 3) sub-cloud broadband radiative flux divergence 4) detailed mapping of surface meltponds/leads ASCOS Planning Meeting

  7. Key Dates May 12-13: testing dropsondes in Palmdale, CA July 17-25: installation/integration of sensors on DC-8, Palmdale CA Aug. 8: Transit of DC-8 to Kiruna Aug. 11: First possible sortie Aug. 29: Last possible DC-8 sortie • Outstanding Issues • Building mounting ferrings for dual-channel radiometers • Building mounting ferrings for broadband radiometers • Building/testing dropsondes in conjunction with Yankee Technology • Finalizing CAPS probe procurement, training staff on system • Finalizing/procuring aerosol inlet system • Procuring accommodations for science staff in Kiruna • Coordination logistics with R/V Oden • (items 4,5 from ARCTAS participants?) ASCOS Planning Meeting

  8. END SLUT FIN ENDE ASCOS Planning Meeting

  9. AMISA SCIENCE OBJECTIVES 3) Validate the NASA Aqua AMSR-E sea-ice concentration retrievals under summer conditions (pre-melt, meltponds, and freezeup) Summer conditions are particularly difficult for the retrieval of sea ice concentration because melt, freeze, meltpond development greatly modify the sea ice and snow emissivities. From Markus and Dokken, 2002 The figure shows modeled sea ice concentration from the NASA Team (NT) and enhanced NASA Team (NT2) for different summer sea ice conditions. The top and bottom figure how the atmosphere is handled. ASCOS Planning Meeting

  10. AMISA SCIENCE OBJECTIVES 4) Validate the atmospheric correction portion of the NASA Aqua AMSR-E sea-ice concentration algorithm The standard AMSE-E sea ice concentration algorithm (NT2; Markus and Cavalieri, 2000) includes an atmospheric correction scheme, which is particularly important in the marginal sea ice zone and during summer. ASCOS Planning Meeting

  11. AMISA SCIENCE OBJECTIVES 5) Develop a microwave (C-/L-band) capability for distinguishing between meltponds and open water areas (leads and polynyas) Meltponds are a critical error source in the determination of sea ice concentration. The sensitivity of water emissivity to salinity may make it possible to distinguish between freshwater meltponds and open ocean areas. Although this sensitivity decreases with decreasing temperature (see Figure). The utilization of lower frequency channels will be explored. 2.65 GHz ASCOS Planning Meeting From Klein and Swift, 1977

  12. Map showing: (a) two primary aircraft sampling regions, and (b) sample high-level transit flight track at 7.5 km altitude to the Oden area. In (b), the Oden is marked by the large black dot, transit legs are shown as black lines, and approximate dropsonde locations marked by “D”. The “S” marks the spiral descents or ascents. The maps also show marginal ice zone and perennial ice on August 17, one day after the historic mean date of freezeup.The box near the Oden shows the primary surface-characterization area. ASCOS Planning Meeting

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