 |
| Titel |
Sources and sinks of HONO in a heterogeneous forest landscape |
| VerfasserIn |
Matthias Sörgel, Dianming Wu, Ivonne Trebs, Andreas Held |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096566
|
| Publikation (Nr.) |
 EGU/EGU2014-12076.pdf |
|
|
|
|
|
| Zusammenfassung |
| Nitrous acid (HONO) profiles were measured on a clearing and at the forest floor in a rural
forest environment. For the forest floor deposition was found to be the predominant process.
At the clearing net deposition was dominating during night whereas during day net emissions
were observed. For selected days it was possible to estimate net fluxes of HONO from
the measured profiles by the aerodynamic gradient method. The emission fluxes
were in the range of 0.02 to 0.07 nmol m-2 s-1 thus in the lower range of previous
results of flux measurements. These fluxes were compared to source strengths of
postulated sources. By measuring different soils samples from both sites an upper
limit for soil emissions fluxes of 0.025 nmol m-2 s-1 could be derived. HONO
formation by light induced NO2 conversion was calculated to be below 0.03 nmol
m-2 s-1 for the respective days, thus being comparable to the potential soil fluxes.
Due to light saturation at low irradiance this reaction pathway was found to be
independent from light intensity most of the day (i.e. only dependent on ambient
NO2).
HONO formation from HNO3 photolysis was calculated based on measured leaf nitrate
loadings and by a) parameterization of HONO formation from photolysis of adsorbed
HNO3 and b) by directly calculating photolysis of surface adsorbed HNO3. Fluxes
calculated by the empirical approach yielded values of the same order as the estimated
fluxes, whereas the fluxes calculated based on kinetic values were much lower. |
|
|
|
|
|
|