Location of the atmospheric data file.  

atmosphere_file file

 
The file must have at least three columns containing the altitude, pressure, and temperature. Missing profiles are filled with 0 (e.g., if you did not specify the ozone profile, there will be no ozone absorption!), with exception of the air density which is calculated from pressure and temperature. Other trace gases may be set by mol_file. The columns are interpreted as follows:

1

Altitude above sea level in km

2

Pressure in hPa

3

Temperature in K

4

air density in cm{}^{{-3}}

5

Ozone density in cm{}^{{-3}}

6

Oxygen density in cm{}^{{-3}}

7

Water vapour density in cm{}^{{-3}}

8

CO2 density in cm{}^{{-3}}

9

NO2 density in cm{}^{{-3}}

The atmosphere is specified top-down, that is, the top level is the first line in the file, the bottom (surface) level the last line. All properties refer to model level z, not to model layer. It is important that the correct units are used, otherwise unpredictable results are guaranteed. Comments start with #. Empty lines are ignored. Please note that there is some redundancy: For air as an ideal gas the density \rho, can be calulated from pressure and temperature, \rho=p/kT. uvspec will check if this relation is fulfilled and will stop if it is not. libRadtran provides the six standard atmospheres by Anderson1986:

afglt

Tropical (tropics)

afglms

Midlatitude Summer (midlatitude_summer)

afglmw

Midlatitude Winter (midlatitude_winter)

afglss

Subarctic Summer (subarctic_summer)

afglsw

Subarctic Winter (subarctic_winter)

afglus

U.S. Standard (US-standard)

which may be chosen by for example  

atmosphere_file tropics

 
or by specifying the full file name. These atmosphere files are found in data/atmmod. If no atmosphere_file is defined, uvspec will automatically select one. If the information time, latitude and longitude are provided in the input file uvspec will choose from the first 5 files, otherwise it takes the U.S. Standard atmosphere.