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3.3.3 Obliquity

Occultations are considered as vertical or close to vertical if their "verticality" is lower than 10°. This information is provided in the Summary Quality GADS of the Level2 products (temperature and atmospheric constituents products and residual extinction products). Because of the less reliable scintillation correction for oblique occultations at altitudes between 20 km and 40 km (see section, vertical profiles retrieved from these oblique occultations should be considered cautiously at these altitudes.

As detailed in section, the validity altitude range of HRTP profiles is larger for vertical occultations (the upper limit of this range depending on the scintillation strength); and the best accuracy is reached for vertical occultations (see Table 3.3 ).

HRTP data outside the validity altitude range (18 km-35 km for vertical occultations) should be considered cautiously.

Vertical occultations

Oblique occultations

validity altitude range

18 km-35 km

20 km-30 km


1-2K in 18 km-30 km

lower accuracy

Table 3.3: HRTP validity altitude range for vertical occultations and for oblique occultations and altitude range for best accuracy.