SEAC4RS Payload Payload Synergies Synergies

Complementarity between aircraft can be considered to fall into three categories. Each has considerations for flight planning: Direct connections – multiple observations of the same parameter; requires comparison; allows aircraft to operate independently (if necessary) Indirect connections – observing the same phenomenon but from a different perspective; combining these perspectives yields new insight; requires the aircraft to fly in close coordination Unique measurements – may feed indirect connections; may enable science only possible with a single aircraft.

Table of measurements with all direct connections highlighted. Need for comparison between all aircraft is evident. DC-8 vs. GV is critical DC-8 or GV vs. ER-2 should be sufficient. N2O is unique to DC-8 and ER-2 Total Water is unique to GV and ER-2

Gas Phase Composition - Tracers Fingerprinting (and quantifying) Sources: Pollution – enhanced NMHCs and Halocarbons Fires – CH3CN, HCN, enhanced NMHCs in absence of CFC enhancement Terrestrial Biosphere – Isoprene and oxidation products Marine – DMS, Methyl Iodide, Methyl nitrate, Bromocarbons Volcanism – SO2, HCl Stratosphere – O3, CO, CO2, N2O, H2O, CFCs Convective Transport (lifetime): Isoprene (~ 1 hour), DMS (~1 day), CH3I (a few days), CO, CO2 Air Mass Ageing (chemistry and mixing): Requires known emission ratio and reactivity; relative measure of processing

Gas Phase Composition – Photochemical Indicators Reactive Nitrogen Partitioning: Oxidation pathways (organic nitrates only on DC-8) Convective Enhancement of Radical Reservoirs: H2O2, CH3OOH, CH2O Convective Enhancement and Solubility: H2O2, CH3OOH, CH2O, HNO3, organic acids Photochemical Clocks: NOx/HNO3, CH3OOH/H2O2 VOC Oxidation and Organic Aerosol (DC-8): organic acids and isoprene products Photochemical Response: Actinic flux

Spectral and Broadband Irradiance (3 Levels) and Multispectral AOD from (DC-8 only): Cloud and aerosol radiative impacts Impact of aerosol layers above and below clouds Flux Divergence and Heating rates Spectral behavior: Asymmetry parameter and Angstrom Exponent Absorption coefficient Albedo Satellite/ER-2 remote sensor validation Demonstration of ACE concepts Aerosol number and size distributions: Fundamental information on aerosol loading and volatility Information on aerosol loadings above 14 km will have to come from remote sensing observations from the DC-8 and ER-2 Radiation and Aerosol Number and Size Distributions

Detailed observations of aerosol composition and optical properties are only available from the DC-8, but is critical to interpretation of remote sensing observations from ALL aircraft. Profiles of optical properties to relate aerosol loading and composition to radiative impacts Aerosol composition makes a critical contribution to the fingerprinting of sources Aerosol Optical Properties and Composition

Cloud particle distribution and habit: Cirrus formation and persistence (complemented by high resolution met data) Importance of habit to heterogeneous chemistry Relevance to radiative impacts Remote Sensing focus is on Aerosols and Clouds (DIAL O3 is the exception) and relies heavily on information from the lower flying aircraft for: Broadband and spectral radiation impacts of aerosols and clouds Aerosol loading, optical properties, and composition Trace gases? Cloud Probes and Remote Sensing