a. The NRLMSISE-00 model [RN.4] shall be used for calculating both the neutral temperature, and the detailed composition of the atmosphere.
b. The JB-2006 model [RN.5] shall be used for calculating the total atmospheric density above an altitude of 120 km.
c. For altitudes below 120 km, NRLMSISE-00 shall be used for calculating the total air density.
NOTE
This recommendation follows the
advice of the CIRA Working Group, sponsored by
a. The NRLMSISE-00 model for species densities shall not be mixed with the JB-2006 model for total density.
b. For worst case high results and analysis periods not exceeding 1 week high daily short-term values given in Table 6‑3 shall be used as input for daily activity together with the high long-term values for the 81-day average activity.
c. For analysis periods longer than 1 week the long term activities given in Table 6‑3 shall be used as input for both, the daily and the 81-day averaged values.
d. For analysis periods longer than 1 week and conditions specified in 6.2.3c, the daily and 81-day averaged solar activities given in Table A-1 shall be used.
e. Short-term daily high solar activity values shall not be used together with low or moderate long-term solar activity values.
NOTE 1 Both models can only predict large scale and slow variations, on the order of 1 000 km (given by the highest harmonic component) and 3 hours. Spacecraft can encounter density variations with smaller temporal and spatial scales partly since they are in motion (for example, +100% or -50% in 30 s), and partly because smaller-scale disturbances certainly occur during periods of disturbed geomagnetic activity.
NOTE 2 Reference values for the key indices needed as inputs for the atmosphere models are given in Clause 6.
NOTE 3 The F10.7 81-day average activity can also be estimated by averaging three successive monthly predicted values.
NOTE 4 Information on density model uncertainties can be found in G.5 and in [RN.4] and [RN.5].
NOTE 5 For high activities the atmosphere models only give realistic results if high short term values are combined with high 81-day averaged values.
NOTE 6 High Ap values can be used with low, moderate or high solar activities.