Creating spectroscopic look-up tables
ArchNEMESIS includes functionality to create line-by-line or correlated-k look-up tables compatible with both archNEMESIS and NEMESIS. These programs are based on the spectroscopic calculations made with the LineData class, so we also encourage the users to also explore this tutorial to better understand how the calculations are performed.
In this notebook, we provide some examples showing how archNEMESIS can be used to create these look-up tables.
[1]:
import archnemesis as ans
import matplotlib.pyplot as plt
import numpy as np
from archnemesis.Data.path_data import archnemesis_path
1. Creating a line-by-line look-up table
We are going to create a look-up table for the main isotope of CO (ID=5, ISO=1) using spectroscopic line data from HITRAN2024, together with the partition sums from TIPS2025.
The main function for creating these look-up tables is called calc_lbltable() and is stored in the Spectroscopy_0.py file. A description of the input parameters is defined below:
[2]:
help(ans.calc_lbltable)
Help on function calc_lbltable in module archnemesis.Spectroscopy_0:
calc_lbltable(outname, gasID, isoID, npress, p0, pn, ntemp, t0, tn, ispace, nwave, wavemin, delwave, iproc, wn_calc_window, wn_approx_window, self_frac, line_database, pf_database='/home/alday/Documents/Projects/archnemesis-dist/archnemesis/Data/partition_functions/tips2025.h5', cont_database=None, include_pressure_shift=True)
Calculate a line-by-line look-up table for a given gas
at specified pressure and temperature levels
Input parameters
-----------------
@param gasID: int
Nemesis gas identifier
@param isoID: int
Nemesis isotopologue identifier
@param npress: int
Number of pressure levels
@param p0: float
Minimum pressure level (atm)
@param pn: float
Maximum pressure level (atm)
@param ntemp: int
Number of temperature levels
@param t0: float
Minimum temperature level (K)
@param tn: float
Maximum temperature level (K)
@param ispace: int
Spectral unit (0 - wavenumbers (cm-1); 1 - wavelength (um))
@param nwave: int
Number of wavenumber/wavelength points
@param wavemin: float
Minimum wavenumber/wavelength (cm-1/um)
@param delwave: float
Wavenumber/wavelength step (cm-1/um)
@param iproc: int
Lineshape identifier (see possible cases in SpectroscopicLineProfileEnum)
@param wn_calc_window: float
Wavenumber window for lineshape calculation (cm-1)
@param wn_calc_window: float
Wavenumber window for lineshape wing approximation (cm-1)
@param self_frac: float
Self-broadening fraction (0 - complete self-broadening, 1 - complete air broadening)
@param line_database: str
Path to archnemesis spectroscopic database to use ('HITRAN','GEISA', etc.)
@param pf_database: str
Path to archnemesis partition function database (default = TIPS2025)
@param cont_database: str
Path to archnemesis pseudo-continuum database (default = None). If None, it is assumed
it is the same as the line_database
@param include_pressure_shift: bool
If True, include pressure shift in the waveumber of the lines
[20]:
#lbl-table inputs
################################################################################
#CO
gasID = 5 ; isoID = 1
outname = "example_co"
npress = 10 ; p0 = 1.0e-6 ; pn = 1.0e-2
ntemp = 10 ; t0 = 130. ; tn = 250.
ispace = 0 #wavenumber (cm-1)
vmin = 2050. ; delv = 0.001 ; nwave = 12001
iproc = 0 #Voigt lineshape
wn_calc_window = 25. #Caclculation window (cm-1)
wn_approx_window = 75. #Caclculation window (cm-1)
self_frac = 0.5 #fraction of self-broadening
line_base = archnemesis_path()+"/tests/files/linedata/CO_1_ambient_AIR.h5"
pf_base = archnemesis_path()+'/archnemesis/Data/partition_functions/tips2025.h5'
#Performing calculations
###################################################################################
#Calculating lbl-table
ans.calc_lbltable(outname, #Name of the output .lta file
gasID,isoID, #Gas information
npress,p0,pn, #Pressure grid
ntemp,t0,tn, #Temperature grid
ispace,nwave,vmin,delv, #Wavenumber grid
iproc, #Lineshape identifier
wn_calc_window, #Wavenumber calculation window (cm-1)
wn_approx_window, #Wavenumber window at which an approximation for the wings is applied (cm-1)
self_frac, #Self-broadening fraction
line_base, #Database
pf_database=pf_base, #Partition function database (default = TIPS2025)
cont_database=None, #Pseudo-continuum database (If not None, it will use the same as the line_database)
include_pressure_shift=True, #Flag to include pressure shift in the waveumbers
)
INFO :: read_tables :: Spectroscopy_0.py-1467 :: Reading tables
INFO :: read_tables :: Spectroscopy_0.py-1474 :: RUNTIME calculation is loading desired wavenumber range from databases
INFO :: read_tables :: Spectroscopy_0.py-1480 :: Reading table self.LOCATION_LD[igas]='/home/alday/Documents/Projects/archnemesis-dist/tests/files/linedata/CO_1_ambient_AIR.h5' wavemin=2050.0 wavemax=2062.0
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
LineData_0::fetch_partition_fn()
Actually getting the partition function
LineData_0::fetch_partition_fn()
Actually getting the partition function
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
INFO :: calc_klbl_online :: Spectroscopy_0.py-2113 :: Gas 5, Isotope 1 - Calculating line-by-line cross sections at runtime...
[21]:
#Reading the table
#Initialising spectroscopy class with ILBL = 2 (line-by-line)
Spectroscopy = ans.Spectroscopy_0(ILBL=2)
Spectroscopy.NGAS = 1 #We define two gases in the class
Spectroscopy.LOCATION = [outname+'.lta']
#Reading the header information
Spectroscopy.read_header()
#Printing summary information
Spectroscopy.summary_info()
WARNING :: read_header :: Spectroscopy_0.py-1281 :: self.NGAS=1 self.LOCATION=PathRedirectList(['example_co.lta'], redirects = {})
INFO :: summary_info :: Spectroscopy_0.py-461 ::
#===== SUMMARY =====#
Spectroscopy_0 instance at memory location 138921419979216
Calculation type ILBL :: (<SpectralCalculationModeEnum.LINE_BY_LINE_TABLES: 2>, ' (line-by-line)')
Number of radiatively-active gaseous species :: 1
Gaseous species :: ['CO (1)']
Number of spectral points :: 12001
Wavelength range :: (np.float64(2050.0), '-', np.float64(2062.0))
Step size :: 0.0010000000002037268
Number of temperature levels :: 10
Temperature range :: (np.float32(130.0), '-', np.float32(250.0))
Number of pressure levels :: 10
Pressure range :: (np.float32(1e-06), '-', np.float32(0.01))
#===================#
[22]:
#Reading the information in the lbl-tables in a specified spectral range
Spectroscopy.read_tables()
fig,(ax) = plt.subplots(Spectroscopy.NGAS,1,figsize=(12,5),sharex=True)
ipress = 0 ; itemp = 0
ax.plot(Spectroscopy.WAVE,Spectroscopy.K[:,ipress,itemp,0],label='Pressure :: '+str(Spectroscopy.PRESS[ipress])+' atm - Temperature :: '+str(Spectroscopy.TEMP[itemp])+' K')
ipress = 0 ; itemp = -1
ax.plot(Spectroscopy.WAVE,Spectroscopy.K[:,ipress,itemp,0],label='Pressure :: '+str(Spectroscopy.PRESS[ipress])+' atm - Temperature :: '+str(Spectroscopy.TEMP[itemp])+' K')
ipress = -1 ; itemp = 0
ax.plot(Spectroscopy.WAVE,Spectroscopy.K[:,ipress,itemp,0],label='Pressure :: '+str(Spectroscopy.PRESS[ipress])+' atm - Temperature :: '+str(Spectroscopy.TEMP[itemp])+' K')
ipress = -1 ; itemp = -1
ax.plot(Spectroscopy.WAVE,Spectroscopy.K[:,ipress,itemp,0],label='Pressure :: '+str(Spectroscopy.PRESS[ipress])+' atm - Temperature :: '+str(Spectroscopy.TEMP[itemp])+' K')
ax.set_yscale('log')
ax.set_ylabel('Absorption cross section (cm$^2$)')
ax.set_title(gasname[i])
ax.legend()
ax.grid()
ax.set_facecolor('lightgray')
ax.set_xlabel('Wavenumber (cm$^{-1}$)')
plt.tight_layout()
INFO :: read_tables :: Spectroscopy_0.py-1467 :: Reading tables
INFO :: read_tables :: Spectroscopy_0.py-1524 :: Reading table self.LOCATION[igas]='example_co.lta' wavemin=0.0 wavemax=10000000000.0
