UNIVERSITY OF LEEDS Institute for Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT VACC - Volatility Aerosol Composition and Concentration

UNIVERSITY OF LEEDS Institute for Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT VACC – Science Summary Is CN mixed into cloud from above and/or below? –Out of cloud deep profiles –Porpoise through area to look for variation in CN –Characterise CN concentration and composion below and above cloud If isolated cloud available characterise CN concentration and composition of inflow and outflow –orbits at different levels or straight and level legs perpendicular to wind. (depends on the extent of the cloud)

UNIVERSITY OF LEEDS Institute for Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT VACC – flight leg requirements CPC – N (R > 5 nm) 10 Hz data flow controlled at 3 l/min all levels No special flight requirements SMPS – dN/dR (5 nm < R < ~200 nm) Scan every 2.5 minutes Sample flow controlled at 1 l/min all levels Sheath flow controlled at 10 l/min all levels Flight requirements: Constant altitude for duration of scan Preferably straight but can deal with wide angle turn/orbit OPC – Volatility – constant temperature – dN/dR (50 nm < R < 1 µm) 1 Hz data Sample flow controlled at 0.12 l/min at all levels No special flight requirements OPC – Volatility – scanning temperature - dN/dR (50 nm < R < 1 µm) Scan every 8 minutes Sample flow controlled at 0.12 l/min at all levels Flight requirements: Constant altitude for duration of scan Preferably straight but can deal with wide angle turn/orbit Summary Flight speed as slow as possible Altitude profiles of CPC and OPC-volatility-set temperature obtainable For SMPS or OPC-volatility – scanning temperature: require straight and level or level in slow turn flight legs. Minimum operational pressure 500 mb ~6000m Cannot operate in cloud

UNIVERSITY OF LEEDS Institute for Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT B047 – 09:22 (UTC)

UNIVERSITY OF LEEDS Institute for Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT No particles R > 0.55μm 75°C 100°C 130°C 160°C 200°C 230°C 260°C 300°C Sample can be considered dry. Ammonium Hydrogen Sulphate Ammonium Sulphate Sodium Hydrogen Carbonate Ammonium Nitrate MSA / Sulphuric acid

UNIVERSITY OF LEEDS Institute for Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT External/Internal Mixing.