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| Titel |
Year-round observations of NOx mixing ratios and fluxes above the coastal snow pack at Halley, Antarctica. |
| VerfasserIn |
Shital Shirsat Rohekar, Neil Brough, Phil Anderson, Anna Jones, Markus M. Frey |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101132
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| Publikation (Nr.) |
 EGU/EGU2015-227.pdf |
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| Zusammenfassung |
| Measurements of NOx (NO + NO2) concentrations at Halley (750S 260W) were carried out
year-round (January – December 2007) for the first time, to provide us with an insight on
its seasonal variability, relationship with various atmospheric parameters and its
influence on surface ozone concentrations. Measurements were done at 7m above
the surface snowpack, and for a few days during each season an additional inlet
was placed at 0.1m to estimate the NOx flux based on the flux-gradient method.
Supporting measurements included 3-D wind vectors with a sonic anemometer,
boundary layer depth with an acoustic SODAR, actinic fluxes with a spectrometer and
meteorology.
The average (± standard error) NOx mixing ratios during summer months (Jan-Feb’07 &
Nov-Dec’07) were 10.4(±0.1) & 8.5(±0.03) pptv, respectively, about 3-5 times greater than
the spring (Mar-Apr’07) and autumn average (Aug-Sept-Oct’07) of 2.7 (±0.02) & 3.04
(±0.017) pptv. During winter (May-June-July’07) the average NOx mixing ratio was below
the detection limit of 5 pptv. A clear diurnal pattern in the NOx concentration was detected
from late spring (Oct) through the summer, with maxima occurring between 1700-1900 hrs
LT. Generally, atmospheric vertical mixing dilutes snowpack emissions of NOx, as indicated
by the weak but significant negative correlation between NOx mixing ratios and the turbulent
diffusivity of heat (Kh) (r = -0.1291, p |
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