Speciation of OH reactivity above the canopy of an isoprene-dominated forest

Measurements of OH reactivity, the inverse lifetime of the OH radical, can provide a top&ndash;down estimate of the total amount of reactive carbon in an air mass. Using a comprehensive measurement suite, we examine the measured and modeled OH reactivity above an isoprene-dominated forest in the southeast United States during the 2013 Southern Oxidant and Aerosol Study (SOAS) field campaign. Measured and modeled species account for the vast majority of average daytime reactivity (80&ndash;95 %) and a smaller portion of nighttime and early morning reactivity (68&ndash;80 %). The largest contribution to total reactivity consistently comes from primary biogenic emissions, with isoprene contributing &sim;&thinsp; 60 % in the afternoon, and &sim;&thinsp; 30&ndash;40 % at night and monoterpenes contributing &sim;&thinsp; 15&ndash;25 % at night. By comparing total reactivity to the reactivity stemming from isoprene alone, we find that &sim;&thinsp; 20 % of the discrepancy is temporally related to isoprene reactivity, and an additional constant &sim;&thinsp; 1 s-1 offset accounts for the remaining portion. The model typically overestimates measured OVOC concentrations, indicating that unmeasured oxidation products are unlikely to influence measured OH reactivity. Instead, we suggest that unmeasured primary emissions may influence the OH reactivity at this site.</p

CMS physics technical design report: Addendum on high density QCD with heavy ions

This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies ,will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction - Quantum Chromodynamics (QCD) - in extreme conditions of temperature, density and parton momentum fraction (low-x). This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include "bulk" observables, (charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high pT hadrons which yield "tomographic" information of the hottest and densest phases of the reaction.0info:eu-repo/semantics/publishe