Simulations of atmospheric OH, O3 and NO3 reactivities within and above the boreal forest

D. Mogensen, R. Gierens, J. N. Crowley, P. Keronen, S. Smolander, Andrey Sogachev, A. C. Nölscher, L. Zhou, M. Kulmala, M. J. Tang, J. Williams, M. Boy

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Abstract

Using the 1-D atmospheric chemistry transport model SOSAA, we have investigated the atmospheric reactivity of a boreal forest ecosystem during the HUMPPA-COPEC-10 campaign (summer 2010, at SMEAR II in southern Finland). For the very first time, we present vertically resolved model simulations of the NO3 and O-3 reactivity (R) together with the modelled and measured reactivity of OH. We find that OH is the most reactive oxidant (R similar to 3 s(-1)) followed by NO3 (R similar to 0.07 s(-1)) and O-3 (R similar to 2 x 10 5 s(-1)). The missing OH reactivity was found to be large in accordance with measurements (similar to 65 %) as would be expected from the chemical subset described in the model. The accounted OH radical sinks were inorganic compounds (similar to 41 %, mainly due to reaction with CO), emitted monoterpenes (similar to 14 %) and oxidised biogenic volatile organic compounds (similar to 44 %). The missing reactivity is expected to be due to unknown biogenic volatile organic compounds and their photoproducts, indicating that the true main sink of OH is not expected to be inorganic compounds. The NO3 radical was found to react mainly with primary emitted monoterpenes (similar to 60 %) and inorganic compounds (similar to 37 %, including NO2). NO2 is, however, only a temporary sink of NO3 under the conditions of the campaign (with typical temperatures of 20-25 degrees C) and does not affect the NO3 concentration. We discuss the difference between instantaneous and steady-state reactivity and present the first boreal forest steady-state lifetime of NO3 (113 s). O-3 almost exclusively reacts with inorganic compounds (similar to 91 %, mainly NO, but also NO2 during night) and less with primary emitted sesquiterpenes (similar to 6 %) and monoterpenes (similar to 3 %). When considering the concentration of the oxidants investigated, we find that OH is the oxidant that is capable of removing organic compounds at a faster rate during daytime, whereas NO3 can remove organic molecules at a faster rate during night-time. O-3 competes with OH and NO3 during a short period of time in the early morning (around 5 a.m. local time) and in the evening (around 7-8 p.m.). As part of this study, we developed a simple empirical parameterisation for conversion of measured spectral irradiance into actinic flux. Further, the meteorological conditions were evaluated using radiosonde observations and ground-based measurements. The overall vertical structure of the boundary layer is discussed, together with validation of the surface energy balance and turbulent fluxes. The sensible heat and momentum fluxes above the canopy were on average overestimated, while the latent heat flux was un-derestimated.
Original languageEnglish
JournalAtmospheric Chemistry and Physics
Volume15
Issue number7
Pages (from-to)3909-3932
Number of pages24
ISSN1680-7316
DOIs
Publication statusPublished - 2015

Bibliographical note

© Author(s) 2015. CC Attribution 3.0 License

Keywords

  • METEOROLOGY
  • CONTINENTAL BOUNDARY-LAYER
  • VOLATILE ORGANIC-COMPOUNDS
  • SCOTS PINE
  • ACTINIC FLUX
  • SULFURIC-ACID
  • SPECTRAL MEASUREMENTS
  • OXIDATION CAPACITY
  • SEASONAL-VARIATION
  • PHOTOCHEMICAL DATA
  • DATA ASSIMILATION

Cite this

Mogensen, D. ; Gierens, R. ; Crowley, J. N. ; Keronen, P. ; Smolander, S. ; Sogachev, Andrey ; Nölscher, A. C. ; Zhou, L. ; Kulmala, M. ; Tang, M. J. ; Williams, J. ; Boy, M. / Simulations of atmospheric OH, O3 and NO3 reactivities within and above the boreal forest. In: Atmospheric Chemistry and Physics. 2015 ; Vol. 15, No. 7. pp. 3909-3932.
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abstract = "Using the 1-D atmospheric chemistry transport model SOSAA, we have investigated the atmospheric reactivity of a boreal forest ecosystem during the HUMPPA-COPEC-10 campaign (summer 2010, at SMEAR II in southern Finland). For the very first time, we present vertically resolved model simulations of the NO3 and O-3 reactivity (R) together with the modelled and measured reactivity of OH. We find that OH is the most reactive oxidant (R similar to 3 s(-1)) followed by NO3 (R similar to 0.07 s(-1)) and O-3 (R similar to 2 x 10 5 s(-1)). The missing OH reactivity was found to be large in accordance with measurements (similar to 65 {\%}) as would be expected from the chemical subset described in the model. The accounted OH radical sinks were inorganic compounds (similar to 41 {\%}, mainly due to reaction with CO), emitted monoterpenes (similar to 14 {\%}) and oxidised biogenic volatile organic compounds (similar to 44 {\%}). The missing reactivity is expected to be due to unknown biogenic volatile organic compounds and their photoproducts, indicating that the true main sink of OH is not expected to be inorganic compounds. The NO3 radical was found to react mainly with primary emitted monoterpenes (similar to 60 {\%}) and inorganic compounds (similar to 37 {\%}, including NO2). NO2 is, however, only a temporary sink of NO3 under the conditions of the campaign (with typical temperatures of 20-25 degrees C) and does not affect the NO3 concentration. We discuss the difference between instantaneous and steady-state reactivity and present the first boreal forest steady-state lifetime of NO3 (113 s). O-3 almost exclusively reacts with inorganic compounds (similar to 91 {\%}, mainly NO, but also NO2 during night) and less with primary emitted sesquiterpenes (similar to 6 {\%}) and monoterpenes (similar to 3 {\%}). When considering the concentration of the oxidants investigated, we find that OH is the oxidant that is capable of removing organic compounds at a faster rate during daytime, whereas NO3 can remove organic molecules at a faster rate during night-time. O-3 competes with OH and NO3 during a short period of time in the early morning (around 5 a.m. local time) and in the evening (around 7-8 p.m.). As part of this study, we developed a simple empirical parameterisation for conversion of measured spectral irradiance into actinic flux. Further, the meteorological conditions were evaluated using radiosonde observations and ground-based measurements. The overall vertical structure of the boundary layer is discussed, together with validation of the surface energy balance and turbulent fluxes. The sensible heat and momentum fluxes above the canopy were on average overestimated, while the latent heat flux was un-derestimated.",
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author = "D. Mogensen and R. Gierens and Crowley, {J. N.} and P. Keronen and S. Smolander and Andrey Sogachev and N{\"o}lscher, {A. C.} and L. Zhou and M. Kulmala and Tang, {M. J.} and J. Williams and M. Boy",
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Mogensen, D, Gierens, R, Crowley, JN, Keronen, P, Smolander, S, Sogachev, A, Nölscher, AC, Zhou, L, Kulmala, M, Tang, MJ, Williams, J & Boy, M 2015, 'Simulations of atmospheric OH, O3 and NO3 reactivities within and above the boreal forest', Atmospheric Chemistry and Physics, vol. 15, no. 7, pp. 3909-3932. https://doi.org/10.5194/acp-15-3909-2015

Simulations of atmospheric OH, O3 and NO3 reactivities within and above the boreal forest. / Mogensen, D.; Gierens, R.; Crowley, J. N.; Keronen, P.; Smolander, S.; Sogachev, Andrey; Nölscher, A. C.; Zhou, L.; Kulmala, M.; Tang, M. J.; Williams, J.; Boy, M.

In: Atmospheric Chemistry and Physics, Vol. 15, No. 7, 2015, p. 3909-3932.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Simulations of atmospheric OH, O3 and NO3 reactivities within and above the boreal forest

AU - Mogensen, D.

AU - Gierens, R.

AU - Crowley, J. N.

AU - Keronen, P.

AU - Smolander, S.

AU - Sogachev, Andrey

AU - Nölscher, A. C.

AU - Zhou, L.

AU - Kulmala, M.

AU - Tang, M. J.

AU - Williams, J.

AU - Boy, M.

N1 - © Author(s) 2015. CC Attribution 3.0 License

PY - 2015

Y1 - 2015

N2 - Using the 1-D atmospheric chemistry transport model SOSAA, we have investigated the atmospheric reactivity of a boreal forest ecosystem during the HUMPPA-COPEC-10 campaign (summer 2010, at SMEAR II in southern Finland). For the very first time, we present vertically resolved model simulations of the NO3 and O-3 reactivity (R) together with the modelled and measured reactivity of OH. We find that OH is the most reactive oxidant (R similar to 3 s(-1)) followed by NO3 (R similar to 0.07 s(-1)) and O-3 (R similar to 2 x 10 5 s(-1)). The missing OH reactivity was found to be large in accordance with measurements (similar to 65 %) as would be expected from the chemical subset described in the model. The accounted OH radical sinks were inorganic compounds (similar to 41 %, mainly due to reaction with CO), emitted monoterpenes (similar to 14 %) and oxidised biogenic volatile organic compounds (similar to 44 %). The missing reactivity is expected to be due to unknown biogenic volatile organic compounds and their photoproducts, indicating that the true main sink of OH is not expected to be inorganic compounds. The NO3 radical was found to react mainly with primary emitted monoterpenes (similar to 60 %) and inorganic compounds (similar to 37 %, including NO2). NO2 is, however, only a temporary sink of NO3 under the conditions of the campaign (with typical temperatures of 20-25 degrees C) and does not affect the NO3 concentration. We discuss the difference between instantaneous and steady-state reactivity and present the first boreal forest steady-state lifetime of NO3 (113 s). O-3 almost exclusively reacts with inorganic compounds (similar to 91 %, mainly NO, but also NO2 during night) and less with primary emitted sesquiterpenes (similar to 6 %) and monoterpenes (similar to 3 %). When considering the concentration of the oxidants investigated, we find that OH is the oxidant that is capable of removing organic compounds at a faster rate during daytime, whereas NO3 can remove organic molecules at a faster rate during night-time. O-3 competes with OH and NO3 during a short period of time in the early morning (around 5 a.m. local time) and in the evening (around 7-8 p.m.). As part of this study, we developed a simple empirical parameterisation for conversion of measured spectral irradiance into actinic flux. Further, the meteorological conditions were evaluated using radiosonde observations and ground-based measurements. The overall vertical structure of the boundary layer is discussed, together with validation of the surface energy balance and turbulent fluxes. The sensible heat and momentum fluxes above the canopy were on average overestimated, while the latent heat flux was un-derestimated.

AB - Using the 1-D atmospheric chemistry transport model SOSAA, we have investigated the atmospheric reactivity of a boreal forest ecosystem during the HUMPPA-COPEC-10 campaign (summer 2010, at SMEAR II in southern Finland). For the very first time, we present vertically resolved model simulations of the NO3 and O-3 reactivity (R) together with the modelled and measured reactivity of OH. We find that OH is the most reactive oxidant (R similar to 3 s(-1)) followed by NO3 (R similar to 0.07 s(-1)) and O-3 (R similar to 2 x 10 5 s(-1)). The missing OH reactivity was found to be large in accordance with measurements (similar to 65 %) as would be expected from the chemical subset described in the model. The accounted OH radical sinks were inorganic compounds (similar to 41 %, mainly due to reaction with CO), emitted monoterpenes (similar to 14 %) and oxidised biogenic volatile organic compounds (similar to 44 %). The missing reactivity is expected to be due to unknown biogenic volatile organic compounds and their photoproducts, indicating that the true main sink of OH is not expected to be inorganic compounds. The NO3 radical was found to react mainly with primary emitted monoterpenes (similar to 60 %) and inorganic compounds (similar to 37 %, including NO2). NO2 is, however, only a temporary sink of NO3 under the conditions of the campaign (with typical temperatures of 20-25 degrees C) and does not affect the NO3 concentration. We discuss the difference between instantaneous and steady-state reactivity and present the first boreal forest steady-state lifetime of NO3 (113 s). O-3 almost exclusively reacts with inorganic compounds (similar to 91 %, mainly NO, but also NO2 during night) and less with primary emitted sesquiterpenes (similar to 6 %) and monoterpenes (similar to 3 %). When considering the concentration of the oxidants investigated, we find that OH is the oxidant that is capable of removing organic compounds at a faster rate during daytime, whereas NO3 can remove organic molecules at a faster rate during night-time. O-3 competes with OH and NO3 during a short period of time in the early morning (around 5 a.m. local time) and in the evening (around 7-8 p.m.). As part of this study, we developed a simple empirical parameterisation for conversion of measured spectral irradiance into actinic flux. Further, the meteorological conditions were evaluated using radiosonde observations and ground-based measurements. The overall vertical structure of the boundary layer is discussed, together with validation of the surface energy balance and turbulent fluxes. The sensible heat and momentum fluxes above the canopy were on average overestimated, while the latent heat flux was un-derestimated.

KW - METEOROLOGY

KW - CONTINENTAL BOUNDARY-LAYER

KW - VOLATILE ORGANIC-COMPOUNDS

KW - SCOTS PINE

KW - ACTINIC FLUX

KW - SULFURIC-ACID

KW - SPECTRAL MEASUREMENTS

KW - OXIDATION CAPACITY

KW - SEASONAL-VARIATION

KW - PHOTOCHEMICAL DATA

KW - DATA ASSIMILATION

U2 - 10.5194/acp-15-3909-2015

DO - 10.5194/acp-15-3909-2015

M3 - Journal article

VL - 15

SP - 3909

EP - 3932

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

SN - 1680-7316

IS - 7

ER -