Landskrona, Sweden April 14-18, 2008 ASCOS Planning Meeting 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 2 CIRES/NOAA/ESRL/PSD, Boulder, Colorado 3 NASA Goddard, Greenbelt, MD 4 Dept. of Meteorology, Univ. of Stockholm, Stockholm, Sweden Other participants: 1)V. Leuski, D. Kraft, grad student, CET at U. of CO 2)B. Brooks, U. of Leeds, UK – aerosol sampling 3)E. Sukovich, CIRES - microphysics Funding obtained from U.S. National Aeronautics and Space Administration (NASA)

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting NASA McDonnell-Douglas DC-8-72 research aircraft 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, To be based in Kiruna, Sweden - 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 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 (NSIDC)

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting 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

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting Instrumentation InstrumentDescriptionObservables Polarimetric Scanning Radiometer (PSR) Multiband polarimteric radiometric imaging system; Airborne AMSR-E equivalent high resolution sea ice mapping; cloud cover; integrated water vapor Dual-channel radiometer (DCR) 21/31 GHz, up/downlookingintegrated water vapor & cloud liquid water above/below aircraft Scanning Low Frequency Microwave Radiometer (SLFMR) L-band salinity mappingL-band brightness; mapped salinity with ~5 ppt precision for lead/meltpond discrimination Cloud, aerosol, and precipitation spectrometer (CAPS) From Droplet Measurements Technology Cloud droplet and ice particle spectra, liquid water content, droplet/ice discrimination Expendable digital dropsondes Yankee TechnologySub-aircraft profiles of temperature, pressure, humidity, and wind OAT Rosemount probeOutside air temperature adjusted for Mach number Air temperature Solar flux pyranometers (SFPs) Hemispheric integrating thermopile irradiance sensors Up- and downwelling shortwave fluxes Volatile Aerosol Concentration and Composition (VACC) University of Leeds' systemAerosol number concentration spectra and aerosol composition

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting Instrumentation 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 Aerosol sampling: Leeds airborne VACC PSR on aircraft CAPS: Cloud Aerosol and Precipitation Spectrometer

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting Flight Tracks 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 Synoptic, high-altitude track 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 Mesoscale/mid-altitude track Low-level track & liquid cloud penetration

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting 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 1)Building mounting ferrings for dual-channel radiometers 2)Building mounting ferrings for broadband radiometers 3)Building/testing dropsondes in conjunction with Yankee Technology 4)Finalizing CAPS probe procurement, training staff on system 5)Finalizing/procuring aerosol inlet system 6)Procuring accommodations for science staff in Kiruna 7)Coordination logistics with R/V Oden (items 4,5 from ARCTAS participants?)

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting END SLUT FIN ENDE

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting 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. 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. From Markus and Dokken, 2002

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting 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.

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting 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. AMISA SCIENCE OBJECTIVES 2.65 GHz From Klein and Swift, 1977

Landskrona, Sweden April 14-18, 2008ASCOS Planning Meeting 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.