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| Titel |
Modelling the impact of satellite retrieved scaled cloud optical thickness on surface UV irradiance and photolysis frequencies for NO2, using Tropospheric Ultraviolet and Visible radiation model |
| VerfasserIn |
Praveen Pandey, Koen De Ridder, Didier Gillotay, Nicole Van Lipzig |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046097
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| Zusammenfassung |
| Clouds affect surface solar irradiance, hence, UV irradiance and also photodissociation, as it
mainly occurs under UV range of solar spectrum. In order to investigate this effect,
Tropospheric Ultraviolet and Visible radiation (TUV) modelling study is conducted over two
stations in Belgium, Ostende (51Ë 14′N, 2Ë 56′E) and Redu (50Ë 00′N, 5Ë 09′E),.for June
2006
Tropospheric Ultraviolet and Visible(TUV) radiation model is a state-of-the-art designed
for studying, among others, the effect of clouds on surface UV radiation and photolysis
frequencies for a range of photolytic dissociation reactions.
Remotely sensed scaled cloud optical thickness (scot) retrieved from Spinning Enhanced
Visible & Infrared Imager (SEVIRI) and solar zenith angle (θ) are major inputs for this
study.
Parametric functions are proposed for UV irradiance under clear sky condition and under
cloudy condition as a function of scot & θ. Photolysis frequency for NO2, as a function of
scot & θ, based on TUV results, is parameterised as well.
Modelling results of UV irradiance are compared with station based measurements. The
comparison is also done with total solar irradiance at the surface. A good agreement between
modelled UV-A and observed UV-A approves the proposed parameterisation. Calculated
photolysis frequencies are also very promising as they were never larger than a few percent of
the typical daytime value of JNO2 ~ 0.01 s-1 when compared to that of earlier studies. |
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