Last updated: 23MAY05
The IDL program l1c.pro (which replaces the old lv2pp.pro) reads
a MIPAS L1B file and a
list of microwindows,
spectra and extracts the microwindows writing them as a
L1C file, suitable
for input to MORSE.
The main program l1c.pro and associated procedures l1c_*.pro
are available as a compressed tar file:
Note that the main program contains a !PATH = ... statement
which should be edited to point to the directory where the other modules are
stored unless all in the local directory.
There is also an IDL procedure read_l1c.pro
which can be used to read in L1C data into a structure, with the microwindow
information conveniently sorted.
To run, eg type .run l1c from the IDL> prompt.
Three terminal inputs are then required:
- L1B file:
- Enter name of the MIPAS L1B file.
- Note that the entered response is saved in a local file
l1c_l1bfil.save, so if the program is run subsequently the prompt will
be L1B file [<CR>= use l1c_l1bfil.save]:
and the user has the option of hitting the carriage return to reuse the same
- Microwindow list [=none]:
- Enter the name of the file containing the list of required microwindows.
- See MORSE inputs
for definition of an input .lst file.
- The file format allows several
such files to be simply appended, eg
mwlist.lst, which contains all the nominal
microwindows used in the MIPAS Off-line processor.
The absorber indices (following the altitude ranges) are not read by
- If the user types carriage return, no apodisation is performed and the
output will simply contain a list of scan/sweep headers (which may be useful
for examining the locations of L1B spectra).
- First,Last Scan Nos [=1, 72]:
(where eg 72 is the number of scans in the L1B file)
- Enter the first and last scan numbers required for processing,
separated by a space or a comma.
- If carriage return is typed, all scans within the L1C file are processed.
- Scans containing a different number of sweeps to the nominal number are
Outputs are written to files
ooooo is the Absolute Orbit Number and ss is the
for definition of the L1C format.
Main differences from lv2pp
Radiance outputs are slightly different to Lv2PP due to the different FFT
and NB apodisation but differences should be a couple of orders of magnitude
less than the NESR.
- About an order of magnitude quicker, mainly due to use of 2^N rather than
2^N + 1 points in FFT.
- Prompts user for microwindow list rather than assuming fixed filename
- Should also work for different spectral resolutions (determined by L1B
- Writes L1C sweep header even for sweeps where no valid MWs are found
- <CR> in response to prompt for L1B filename gives last
L1B filename used,
if any, in current directory (saved in file l1c_l1bfil.save)
- <CR> in response to prompt for list of microwindows simply writes out the
sweep headers (useful for extracting time/location information from
scans/sweeps in L1B file).
- Change of output format to L1C v2.0. Only difference
is an extra record after the format identifier. Can also handle nominal
altitudes for 27 sweeps (assumed to be the new scan pattern 6, 7.5 ... 70km).
To continue generating output as v1.5, change line in l1c.pro
L1CFMT = 2.0
L1CFMT = 1.5
- Fix bug in module l1c_inpmds which misread spectra following
corrupt L1B bands, eg if AB band was corrupt, A microwindows were OK, AB
microwindows were excluded (as required) but B, C and D band microwindows
were extracted from the wrong parts of the spectrum.
- Main changes from previous version (19NOV04)
- Addition of internal parameter RESFAC to allow the output
resolution to be changed (eg to simulate low resolution data)
- Output microwindows according to nominal rather than actual altitude
- Add nominal altitude to output files, L1C format updated from
v1.4 to v1.5 accordingly.