caa a22 4500 475823303 CHVBK 20180406123824.0 cr unu---uuuuu 170329e20000901xx s 000 0 eng 10.1023/A:1006322926426 doi (NATIONALLICENCE)springer-10.1023/A:1006322926426 The Impact of Precipitation Scavenging on the Transport of Trace Gases: A 3-Dimensional Model Sensitivity Study [Elektronische Daten] [Paul Crutzen, Mark Lawrence] With the global Chemistry-Transport model MATCHsensitivity simulations were performed to determinethe degree to which especially upward transport ofgases from the earth's surface is limited byconvective and large-scale precipitation scavenging.When only dissolution of species in the liquid phaseis taken into account, mixing ratio reductions in themiddle and upper troposphere by ≈10% arecalculated for gases with a Henry's Law constant H of103 mol/l/atm. The removal increases to ≈50% forH = 104 mol/l/atm, and to 90% for H =105 mol/l/atm. We also consider scavenging by theice phase, which is generally much less efficient thanby the aqueous phase. In fact, rejection of gases fromfreezing water droplets may be a source of trace gasat higher altitudes.H2O2 and the strong acids (H2SO4,HNO3, HCl, HBr, HI) have such large solubilitiesthat they become largely removed by precipitation.When significant concentrations of these gases andsulfate aerosol exist above the liquid water domain ofthe atmosphere, they have likely been produced thereor at higher altitudes, although some could have comefrom trace gas rejection from ice particles or fromevaporating hydrometeors. Several other gases areaffected by precipitation, but not strongly enough toprevent fractional transfer to the middle and uppertroposphere: e.g., HNO4, HNO2 at pH ≤5,CH2O, the organic acids at pH ≤6,CH3SOCH3, HOCl, HOBr, and HOI. NH3 islargely removed by liquid phase scavenging at pH ≤7 and SO2 atpH ≥7. At pH less thanabout 6, upward transport of SO2 should largelydepend on the efficiency of oxidation processes in thewater droplets by O3 and H2O2.Most gases have solubilities which are too low forsignificant precipitation scavenging and aqueous phaseoxidation to occur. This holds, e.g., for O3, CO,the hydrocarbons, NO, NO2, HCN, CH3CN,CH3SCH3, CH3O2H, CH3CHOandhigher aldehydes, CH3OH and higher alcohols,peroxyacetylnitrate (PAN), CH3COCH3 andother ketones (note that some of these are not listedin Table I because their solubilities are below 10mol/l/atm). Especially for the short-lived gases,transfer from the boundary layer to the middle andupper troposphere is actually promoted by the enhancedupward transport that occurs in clouds. Kluwer Academic Publishers, 2000 precipitation scavenging nationallicence Henry's Lawdependence nationallicence global model study nationallicence convection nationallicence gasrejection on freezing nationallicence trace gas vertical transport nationallicence Crutzen Paul Max Planck Institute for Chemistry, Joh. Joachim-Becher-Weg 27, 55128, Mainz, Germany aut Lawrence Mark Max Planck Institute for Chemistry, Joh. Joachim-Becher-Weg 27, 55128, Mainz, Germany aut Journal of Atmospheric Chemistry Kluwer Academic Publishers 37/1(2000-09-01), 81-112 0167-7764 37:1<81 2000 37 10874 https://doi.org/10.1023/A:1006322926426 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1006322926426 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Crutzen Paul Max Planck Institute for Chemistry, Joh. Joachim-Becher-Weg 27, 55128, Mainz, Germany aut NATIONALLICENCE 700 1- Lawrence Mark Max Planck Institute for Chemistry, Joh. Joachim-Becher-Weg 27, 55128, Mainz, Germany aut NATIONALLICENCE 773 0- Journal of Atmospheric Chemistry Kluwer Academic Publishers 37/1(2000-09-01), 81-112 0167-7764 37:1<81 2000 37 10874 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer