ESA Earth Home Missions Data Products Resources Applications
    24-Jul-2014
EO Data Access
How to Apply
How to Access
Index
  Acknowledgements and contact
List of figures and tables
List of tables
 Additional information on the GOMOS measurements
Periods of data unavailabilities
Evolution of the IPF
Glossary
List of abbreviations and acronyms
Product types and structure
Other sources of information
GOMOS-related ESA web pages
Publications (peer-reviewed publications and proceedings of conferences)
Secondary products
Scintillation and turbulence
Aerosols and PSC
Product validation
NO2 and NO3 measurements
O3 measurements
CAL/VAL activities
Retrieval and processing issues
Assimilation of GOMOS products
Mesosphere
Specific events
GOMOS-related theses
Other technical reports by members of GOMOS SAG, ESL and QWG
Level2 processing
How to
FAQ
Access tools
GOMOS products toolbox
EnviView
Data selection
PCD summary in the Level2 products
Obliquity
Star properties
Data availability
Presentation of the GOMOS products
Description of the products
Product content
Product structure
Time availability
Data size
Presentation of the instrument and the measurements
Scientific achievements
Validation results
Measurement characteristics
Accuracy
Occultation obliquity
Geographical and time coverage
Star characteristics
Mission planning
Modified mission scenario since August 2005
Instrument description and measurement principle
Calibration phase and monitoring activities
Measurement technique
GOMOS Product Handbook
Content of the products
Services
Site Map
Frequently asked questions
Glossary
Credits
Terms of use
Contact us
Search


 
 
 


1.5.3 Occultation obliquity

The occultation obliquity is defined as the angle between the motion of the line of sight (with respect to the atmosphere) and the direction of the Earth's centre. The altitude chosen to calculate the obliquity is fixed to 35 km for any occultation. For a tangent occultation, this altitude may be never reached, and in that case, the obliquity is arbitrarily fixed to 90°. For a purely vertical occultation, the obliquity is equal to 0°. The obliquity varies in the same direction as the azimuth direction of the line-of-sight. This is illustrated in Figure 1.7 for an example set of 5000 occultations. For occultations taking place in the orbital plane (azimuth value close to 0), the obliquity is close to 0 (close to vertical occultations). Occultations measured with a field-of-view outside the orbital plane (larger azimuth value) are oblique.

graphic

Figure 1.7: Occultation obliquity (°) versus instrument azimuth direction (°) (measurements made between 08/03/2004 and 20/03/2004).