The 6 model atmospheres in MODTRAN® differ most significantly in their temperature profiles, and in their H2O and O3 profiles. The temperature profiles are illustrated in Figure 1. Not surprisingly, the Sub-Arctic Winter Atmosphere has the coolest surface temperature; the Mid-Latitude Winter Atmosphere has the next coolest surface temperature. The Tropical and Mid-Latitude Summer Atmospheres have the warmest surface temperatures. At the tropopause, the temperature of the Tropical Atmosphere is the coolest and the temperature of the Sub-Arctic Summer Atmosphere is the warmest. For all 6 atmospheres, a secondary temperature peak occurs near 50 km; here the Sub-Arctic Summer temperature is the warmest, essentially equal to that of the Mid-Latitude Summer. The Sub-Arctic Winter temperature is the coolest at this altitude. The 1976 U.S. Standard Atmosphere temperature profile provides an effective median for the set of profiles.
Figure 2 contains the density profiles for H2O and O3. Total vertical column amounts for the 12 ambient band model species are listed in Table 1; the CO2 mixing ratio used in creating this table was 380 ppmV. The 6 model atmospheres provide a nice spread of boundary layer and lower tropospheric water densities.
Mol\Atm | Tropical | Mid Lat Summer | Mid Lat Winter | Sub Arc Summer | Sub Arc Winter | US Standard |
H2O | 5119.4 | 3635.9 | 1059.7 | 2589.4 | 517.73 | 1762.3 |
O3 | 0.27727 | 0.33176 | 0.37681 | 0.34492 | 0.3755 | 0.34356 |
CO2 | 305.87 | 305.13 | 305.99 | 303.47 | 304.21 | 304.48 |
CO | 0.087663 | 0.08774 | 0.090032 | 0.088048 | 0.090924 | 0.088742 |
CH4 | 1.3243 | 1.2684 | 1.2806 | 1.2556 | 1.2719 | 1.3203 |
N2O | 0.24649 | 0.23743 | 0.24037 | 0.2192 | 0.23993 | 0.24593 |
O2 | 168230 | 167820 | 168290 | 166910 | 167320 | 167460 |
NH3 | 0.00016986 | 0.00017121 | 0.00018032 | 0.00017393 | 0.00018409 | 0.00017517 |
NO | 0.00031691 | 0.00032271 | 0.00030953 | 0.00032243 | 0.00030233 | 0.0003139 |
NO2 | 0.00021091 | 0.00021814 | 0.00019842 | 0.00021543 | 0.00018654 | 0.00020418 |
SO2 | 0.00010799 | 0.00010838 | 0.00011245 | 0.00010928 | 0.00011391 | 0.00010997 |
HNO3 | 0.00037983 | 0.00038298 | 0.00035617 | 0.00037403 | 0.00033808 | 0.00036287 |