Try to find the absorption coefficients of the atmiospheric constituents (ozone, water vapour, CO2, methane...) in the Radiative Transfer Codes such as MODTRAN, LibRadTran, and many others. They are all similar and they all have the same problem: the absorption coefficients of aerosols are the lest well known.
you need to do the calculations by yourself, it is pretty simple. Unless someone has already generated Atmospheric Transmittance (which depends on Atmospheric Profiles you selected or inputted), and suit your needs..
i thank everyone for their help and i'm glad that so many people replied, but if nobody has given me what i asked what should i say?
In the first i only specified what i needed replying the previous question, in the second reply i just said that nothing provided still helped me. I don't think to have replied in a bad way. Anyway, THANK YOU for your advice.
i need a text file inside which there is a two column data (lambda and transmission or absorption %) of a typical atmospheric transmission or absorption. The lambda range has to start at least from 300 nm. Since i have no time to calculate it with the various softwares and i can't install them i only need this file instead of a plot. That's all...
Only to clarify the things and then i'll quit this conversation because i don't want to quarrel and i don't have time to waste.
No one has obliged anyone to answer my question and who answered made it by his own. I only specified with THAT'S ALL that my request was simpler that what it seemed.
And i wanted to specify that if anyone has this file ready could give it to me and if they haven't it doesn't bother, i will make without it!sincerely i don't know why you continue woth this silly discussion.
I am also searching the values of absorption cross section for various reactive species. For example, for hydroxyl radical it is 1.2 x 10^-16 cm^2 at 309 nm. Could someone help me with the absorption cross section of Nitric oxide with its wavelength ? Is there any way of calculation ?
Are you looking for actual instrumented measurement of atmospheric spectra? If so, there are no easy answers to your question. Indeed, I don't know of ANY simple/txt etc files of this sort. However, you can (with a lot of work) get the satellite etc data, and then convert those file formats to whatever you like.
QUESTION: are you looking for spectra of the radiation that:
1) Arrives from the Sun?
2) Arrives at the Earth's surface?
3) Is radiated from the Earth's surface as seen from space/satellites?
You may wish to start by getting a hold of this: "GEWEX Radiative Flux Assessment (RFA)" (i.e. http://www.wcrp-climate.org/ documents/GEWEX%20RFA-Volume% 201-report.pdf)
Some other sources are as reported by the WMO earlier this year are (and I quote):
"Surface Radiation Budget data (https://gewex-srb.larc.nasa.gov/common/php/SRB_data_products.php) are ready for a long term release and CERES (https://ceres.larc.nasa.gov/order_data.php) is updating to their Edition 4. There is also a MEASURES Project that will recalibrate and issue a new ERBE data set (https://science.larc.nasa.gov/erbe/). "
Once again, the datasets of instrumented measurements at those and other locations come in a somewhat complex data format since they represents many many sweeps by satellites from many locations and many angles etc etc. I have written some code to "translate" some of those data files into something useful (e.g. to "load into a spreadsheets" etc), but my code is NOT ready for "prime time".