Nadir Brightness Temperature
*FLG section specifies the NAD flag for downward viewing through a plane parallel atmosphere; the BBT flag to output the brightness temperature spectrum and, mandatory with nadir-viewing, the SFC flag indicating that surface conditions are to be specified.
In the *SEC section the value 1.015 corresponds to sec ( 10 deg ), i.e., viewing 10 degress off-nadir.
The *SFC section specifies the surface temperature (288.2 K, in this case the same as the temperature of the lowest level of the atmosphere) and the surface emissivity 1.0 (the emissivity is optional, had it not been specified a value of 1.0 would have been assumed anyway).
*HDR 19AUG13 RFM Example: nadir brightness temperature *FLG NAD BBT SFC *SPC 1220 1230 0.1 *GAS CH4 H2O N2O *ATM ../atm/usa.atm *SEC 1.0 *HIT ../hit/hitran_2012.bin *SFC 288.20 1.0 *END