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user_area:fluorescence_explorer_flex [2013/10/15 12:03]
arve
user_area:fluorescence_explorer_flex [2013/10/15 19:20]
arve
Line 32: Line 32:
 resolution((Fontenla,​ J., White, O. R., Fox, P. A., Avrett, E. H., and resolution((Fontenla,​ J., White, O. R., Fox, P. A., Avrett, E. H., and
 Kurucz, R. L.: Calculation of solar irradiances. I. Synthesis of the Kurucz, R. L.: Calculation of solar irradiances. I. Synthesis of the
-solar spectrum, The Astrophysical Journal, 518, 480499, 1999.))+solar spectrum, The Astrophysical Journal, 518, 480-499, 1999.))
 The solar spectrum must have the same units as the fluorescence The solar spectrum must have the same units as the fluorescence
 spectrum. We use units of photons/​nm/​s/​m<​sup>​2</​sup>​ in order to be spectrum. We use units of photons/​nm/​s/​m<​sup>​2</​sup>​ in order to be
Line 40: Line 40:
   source solar ./​UVSPEC_FLUORESCENCE_kurucz_640.0_810.0.dat_vac_0.01_0.01   source solar ./​UVSPEC_FLUORESCENCE_kurucz_640.0_810.0.dat_vac_0.01_0.01
  
-The wavelengths to be covered are set as follows:+Also note that inclusion of fluorescence requires that internally the 
 +transmittance is calculated at the same grid as the solar_file. The 
 +first wavelength in the ''​wavelength_grid_file''​ must be the same as 
 +that specified by ''​wavelength''​. ​The wavelengths to be covered are 
 +set as follows: ​ 
  
   wavelength 750 770 #  O2-A band   wavelength 750 770 #  O2-A band
 +  wavelength_grid_file ​ kurucz_750_801_trans_0.01
  
 Change this to  Change this to 
   ​   ​
   wavelength 677 697 #  O2-B band   wavelength 677 697 #  O2-B band
 +  wavelength_grid_file ​ kurucz_677_801_trans_0.01
  
-for the  O<​sub>​2</​sub>​-B band.+for the  O<​sub>​2</​sub>​-B band. Note that ''​wavelength_grid_file''​ does 
 +not have to be included if ''​raman''​ is specified.
  
 ===== O2-A and B band absorption ===== ===== O2-A and B band absorption =====
Line 103: Line 111:
 abs_lines_per_speciesCreateFromLines abs_lines_per_speciesCreateFromLines
  
-# Atmospheric profiles ​(there is several data in the +# Atmospheric profiles
-# arts-xml-data/​atmosphere directory, fascod includes the standard +
-# atmospheres which we also have in libRadtran (altitude only up to +
-# 95 km !!). When you want to use the molecular_tau_file from arts, +
-# the atmosphere_file for uvspec must correspond to the ARTS +
-# atmosphere files which are defined here!!) ​+
 AtmRawRead( t_field_raw,​ z_field_raw,​ vmr_field_raw,​ abs_species, ​ AtmRawRead( t_field_raw,​ z_field_raw,​ vmr_field_raw,​ abs_species, ​
   "/​home/​arve/​arts/​arts-xml-data-1.1.31/​atmosphere/​fascod/​midlatitude-summer"​ )   "/​home/​arve/​arts/​arts-xml-data-1.1.31/​atmosphere/​fascod/​midlatitude-summer"​ )
Line 143: Line 146:
  
   mol_tau_file abs ./​UVSPEC_FLUORESCENCE_arts-640-810.nc   mol_tau_file abs ./​UVSPEC_FLUORESCENCE_arts-640-810.nc
- 
  
 ===== Atmosphere ===== ===== Atmosphere =====
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   umu 1     # Looking down   umu 1     # Looking down
   zout toa  # top of atmosphere   zout toa  # top of atmosphere
-  ​ 
  
-  ​+===== Rotational Raman scattering ===== 
 +Rotational Raman scattering may be included by adding the following 
 +line. Note that this will increase the computing time by about a 
 +factor of 480. 
 + 
 +  #raman # Uncomment to include rotational Raman scattering. 
 + 
 +===== Miscellanoues ===== 
 +In addition to the above input we need to specify where uvspec may 
 +find additional data files, what radiative transfer solver to use 
 +(only disort can handle fluorescence and rotational Raman scattering 
 +at the moment) 
 + 
 +  data_files_path /​home/​arve/​develop/​libRadtran/​data/​ 
 +  number_of_streams 16 
 +  rte_solver disort 
 + 
 +As output we want solar irradiance (''​edir''​),​ upward irradiance (''​eup''​) and 
 +nadir radiance (''​uu''​ as specified by ''​umu''​ above) ​ as a function 
 +of wavelength 
 + 
 +  output_user lambda edir eup uu 
 + 
 +And we turn of any warning messages. 
 + 
 +  quiet     # Turn of messages. 
 + 
 +===== Complete uvspec input file ===== 
 +With all this in place the complete uvspec input file is (with some 
 +comments included) 
 +<​code>​ 
 +atmosphere_file ./​afglms_95.dat 
 + 
 +# Note that solar_file and fluorescence_file must have the same units. 
 +source solar ./​UVSPEC_FLUORESCENCE_kurucz_640.0_810.0.dat_vac_0.01_0.01 
 + 
 +# Fluorescence and top of canopy reflectance spectra  
 +fluorescence_file ./​UVSPEC_FLUORESCENCE.FLU_ph 
 +albedo_file ./​UVSPEC_FLUORESCENCE.TOC 
 + 
 +#  Use gas absorption calculated by arts. 
 +mol_tau_file abs ./​UVSPEC_FLUORESCENCE_arts-640-810.nc 
 + 
 +# Specify wavelength region 
 +wavelength 750 770 #  O2-A band 
 +wavelength_grid_file ​ kurucz_750_810_trans_0.01 
 +#wavelength 677 697 #  O2-B band 
 +#​wavelength_grid_file ​ kurucz_677_810_trans_0.01 
 +#wavelength 650 800 #  Both, very memory consuming if raman is on. 
 +#​wavelength_grid_file ​ kurucz_650_801_trans_0.01 
 + 
 +sza 30.0 
 +umu 1 # Simulate nadir viewing satellite. 
 +zout toa 
 + 
 +data_files_path /​home/​arve/​develop/​libRadtran/​data/​ 
 +number_of_streams 16 
 +rte_solver disort 
 + 
 +output_user lambda eglo eup uu 
 +quiet 
 +#raman # Uncomment to include rotational Raman scattering. 
 +</​code>​ 
 + 
 +===== Clouds and aerosols ===== 
 +No aerosol nor liquid water and ice clouds are included in this 
 +examples. These may be included as described in the 
 +[[http://​www.libradtran.org/​doc/​libradtran.pdf|libRadtran User'​s 
 +Guide]].  
 + 
 +===== Note on input directory and file names ===== 
 +Note that the input file contains references to other files with input 
 +data. The file path to these files must be correctly set in order to 
 +run this example. As the paths are set they reflect my setup. 
 + 
 +===== Results ===== 
 +uvspec is run with the following command (assuming the input is stored 
 +in the file ''​UVSPEC_FLUORESCENCE.INP''​) 
 + 
 +  uvspec < UVSPEC_FLUORESCENCE.INP > UVSPEC_FLUORESCENCE_650_880_noraman.OUT 
 + 
 +The output from uvspec is at 0.01 nm resolution. We want it at FLORIS 
 +resolution. This is achieved by convolution by a spectral response 
 +function with FWHM of 0.3 nm. We assume it to be triangular and 
 +generate it with the command: 
 + 
 +  make_slitfunction -f 0.3 -r0.001 > SLIT_0.3.dat 
 + 
 +The convolution is carried out with the libradtran ''​conv''​ tool. 
 + 
 +  conv UVSPEC_FLUORESCENCE_650_880_noraman.OUT SLIT_0.3.dat ​ > UVSPEC_FLUORESCENCE_650_880_noraman.OUTc_0.3 
 + 
 +The TOA radiance for the full wavelength region covered by the 
 +O<​sub>​2</​sub>​-A and B bands,is shown in the Figure below at high, 0.01 
 +nm (blue line), and FLORIS, 0.3 nm (magenta line), spectral resolution. The 
 +fluorescence spectrum, multiplied by a factor of 100, is shown in red 
 +while the surface albedo used for the simulation is shown by the green 
 +line. 
 + 
 +{{:​user_area:​fluorescence_explorer_flex:​toa_spectra.png?​600|}} 
 + 
 +The radiance for the O<​sub>​2</​sub>​-B band with and without 
 +fluorescence is shown in the Figure below.  
 + 
 +{{:​user_area:​fluorescence_explorer_flex:​toa_fluor_02b.png?​600|}} 
 + 
 +Rotational Raman scattering was included in the spectra above. The 
 +filling-in with and without fluorescence is given below: 
 + 
 +{{:​user_area:​fluorescence_explorer_flex:​toa_fi_02b.png?​600|}} 
 + 
 +===== Input files ===== 
 +The various input and output files discussed above are available as a 
 +gzipped tar ball 
 +{{:​user_area:​fluorescence_explorer_flex:​flex_example.tgz|}}.
  
 
 
user_area/fluorescence_explorer_flex.txt · Last modified: 2013/10/16 08:55 by arve
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