|
The GOME ozone monitoring instrument |
|||||||||||||||||
Tropospheric
|
||||||||||||||||||
|
monitoring |
|
NO2
- global - central Europe CH2O - global CO - global |
|
|
|
UV
- UV index - UV dose |
|
related gases |
|
Ozone
- total column - global field - ozone bulletin - ozone profiles BrO - global field |
|
|
|
Aerosol
- AOD - aerosol index Methane - global Clouds - cloud info |
|
emissions |
|
Volcanic plume
- SO2 & AAI |
|
|
23 January 2004
Subjects:
- General introduction
- Monitoring of ozone and other species
- Example: retrieval of the ozone column from the spectra
- ERS orbit and GOME's global coverage
- Data delivery
Retrieval of the ozone column from the spectra
To illustrate briefly how information is retrieved from spectra, consider
the retrieval of the total ozone column from the spectral features around
330 nm with a method named DOAS (Differential Optical Absoption
Spectroscopy), which uses the reflectivity, the ratio between the
Earthshine and solar spectrum. The figure on the right shows the
reflectivity in the relevant wavelength window for the same example as shown
above.
The specific absorption structures, their depth and width, in the
reflectivity are a measure for the amount of ozone along the lightpath
through the atmosphere. This value is then converted into the total ozone in
a vertical column of air above the ground pixel that GOME measured.
The latter step is a rather complex procedure and involves knowledge
the various effects that affect the absorption structures:
the viewing geometry (in what direction is GOME actually looking), the
position of the Sun in the sky, the temperature of the atmosphere,
information of clouds in the line of sight, etc.
Subjects:
- General introduction
- Monitoring of ozone and other species
- Example: retrieval of the ozone column from the spectra
- ERS orbit and GOME's global coverage
- Data delivery