The OPAC ftp distribution:
Version
This is Version 3.1a of OPAC. It is the first official release. Further
information can be found here:
Download
OPAC is available here.
Feedback
We don't get any funding for this project and thus we can't spend much
time for it. But we appreciate any hints about problems with the data set
or suggestions for its improvement, and we will try to discuss and include
them in future versions. Please feel free to send
us an email.
Hardware requirements
OPAC consists of ASCII files, which contain the optical properties of cloud
and aerosol components, and of a FORTRAN program, which allows to handle
the data. The FORTRAN program was tested to compile and run under DOS (Microsoft
Fortran 5.0), Linux (GNU f2c converter), DEC Ultrix, HP Unix, and SunOS.
The whole package requires about 3.5 MB storage capacity.
Installation
To install OPAC, please extract the archive in an empty directory:
> gzip -d opac31a.tar.gz
> tar -xvf opac31a.tar
This will create 2 subdirectories and copy all files in their appropriate
places. The tar and gzip programs are also available for DOS (e.g.
here).
If you did already install the Global Aerosol Data
Set (GADS), you should install OPAC in the same directory, since GADS
and OPAC use the same set of optical data of aerosol components, which
are stored in the subdirectory optdat.
Now the FORTRAN program has to be compiled. On most UNIX computers,
this requires something like:
> f77 opac.f -o opac
In this case, opac will be the name of the executable file. Some
compilers give warning errors, which may be ignored. If you want to use
a DOS computer, you must comment out lines 505-507 instead of 501-503 in
opac.f. The "\" character is not understood by all compilers.
The following files belong to OPAC:
-
The optical properties of the clouds and of the 10 aerosol components,
for up to 8 relative humidities and 61 wavelengths are stored in the subdirectory
optdat.
Each cloud or aerosol component has up to 8 files (for the humidity classes),
each containing data for all 61 wavelengths. The filename consists of a
4 letter approximation for the cloud or the aerosol component, combined
with the relative humidity, for which the optical properties have been
calculated. For clouds only 1 file exists, which is attributed to 0% humidity,
indicating that there is no dependence of size distribution with relative
humidity taken into account.
~ |
0% |
50% |
70% |
80% |
90% |
95% |
98% |
99% |
insoluble |
inso00 |
- |
- |
- |
- |
- |
- |
- |
watersoluble |
waso00 |
waso50 |
waso70 |
waso80 |
waso90 |
waso95 |
waso98 |
waso99 |
soot |
soot00 |
- |
- |
- |
- |
- |
- |
- |
sea salt(acc. mode) |
ssam00 |
ssam50 |
ssam70 |
ssam80 |
ssam90 |
ssam95 |
ssam98 |
ssam99 |
sea salt(coa. mode) |
sscm00 |
sscm50 |
sscm70 |
sscm80 |
sscm90 |
sscm95 |
sscm98 |
sscm99 |
mineral (nuc. mode) |
minm00 |
- |
- |
- |
- |
- |
- |
- |
mineral (acc. mode) |
miam00 |
- |
- |
- |
- |
- |
- |
- |
mineral (coa. mode) |
micm00 |
- |
- |
- |
- |
- |
- |
- |
mineral (transported) |
mitr00 |
- |
- |
- |
- |
- |
- |
- |
sulfate droplets |
suso00 |
suso50 |
suso70 |
suso80 |
suso90 |
suso95 |
suso98 |
suso99 |
. |
. |
. |
. |
. |
. |
. |
. |
. |
stratus (continental) |
stco00 |
- |
- |
- |
- |
- |
- |
- |
stratus (maritime) |
stma00 |
- |
- |
- |
- |
- |
- |
- |
cumulus (cont., clean) |
cucc00 |
- |
- |
- |
- |
- |
- |
- |
cumulus (cont., poll.) |
cucp00 |
- |
- |
- |
- |
- |
- |
- |
cumulus (maritime) |
cuma00 |
- |
- |
- |
- |
- |
- |
- |
fog |
fogr00 |
- |
- |
- |
- |
- |
- |
- |
cirrus 1: -25°C |
cir100 |
- |
- |
- |
- |
- |
- |
- |
cirrus 2: -50°C |
cir200 |
- |
- |
- |
- |
- |
- |
- |
cirrus 3: -50°C
(+ small particles) |
cir300 |
- |
- |
- |
- |
- |
- |
- |
-
All other files are stored in the subdirectory OPAC31. Here you
can find the FORTRAN program and additional configuration and data files:
-
opac.f is the FORTRAN program. It is used to calculate data which
are not directly stored in the data base.
-
opac.cfg contains all the microphysical information about the aerosol
and cloud size distributions, the aerosol height profiles, the composition
of aerosol types.
-
extback.dat contains wavelength dependent extinction coefficients
of the background aerosols, i.e. the free tropospheric aerosol, the stratospheric
aerosol and the mineral aerosol in the desert dust layer. These values
are needed for calculating optical depths.
-
solar.dat contains information about the extraterrestrial solar
flux. This is needed for calculations of spectrally weighted broadband
extincion properties in the solar spectral range.
-
ter.dat contains information about the terrestrial emission between
8 µm and 15 µm for a temperature of 300 K. This is needed for
calculations of spectrally weighted broadband extincion properties in the
terrestrial spectral range.
-
wel.dat contains wavelength information for the calculation of spectrally
weighted extinction properties.
There are 2 subdirectories in directory OPAC31:
-
input: Each input file for opac.f, which contains data and parameters
to be extracted from OPAC must be stored in a file in this directory. The
program prompts you for the filename and automatically appends the extension
".inp". As an example, the file opac.inp is provided.
-
result: Here the results of your inquiry are stored. The given filename
is used with the extension ".out". As an example, the file opac.out
belonging to opac.inp is provided.
Using the program
The purpose of the program is to mix optical properties of single cloud
or aerosol components (stored for 1 particle/cm^3) to optical properties
of clouds or aerosol types, which may consist of several components. It
is also possible to calculate optical properties which are not stored in
the data base. These are for instance the optical depth, the extinction
ratio (extinction coefficient divided by mass), or quantities which are
integrated over the solar or terrestrial wavelength range.
Before starting the program, you have to edit an input file in order
to define, which information you want to extract and calculate from the
data base. Since the program prompts you for the name of the input file,
you can use copies of the example and default input file opac.inp.
The program is started by typing opac in the subdirectory
opac31,
if you used the compiler command shown above.
The results are stored in the subdirectory result in files, whose
names consist of the input file name, but with the extension .inp
replaced by .out.
If you have the feeling, that the instructions given in this file, together
with the explanations in the OPAC paper (Hess
et al., 1998) are not sufficient, please
let us know.
This page was created by: Michael
Hess
update: 12. Mar. 1998