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SciaL1C Command-line Tool


blue arrow DESCRIPTION

The SCIAMACHY Calibration and Extraction Tool (SciaL1C), version 3.2, is an application for processing SCIAMACHY Level 1b products. This application allows you to select specific calibrations to apply to Level 1b data, which are in the case of SCIAMACHY, defined as not fully calibrated Level 0 channel information in combination with calculated calibration data. 

What is SciaL1C?

  • Calibration and extraction tool for SCIAMACHY Level 1b data
  • Command-line based utility
  • UNIX-like syntax, e.g. SciaL1C –option1 –option2   L1b-product-name
  • Batch processing allowed

System requirements

SciaL1C version 3.2 is available for the following platforms:

  • Linux on x86 (i686-pc-linux-gnu)
  • Linux on amd64 (x86_64-pc-linux-gnu)
  • Windows (i686-pc-windows)

What can the SciaL1C tool do?

A complete description of the SciaL1c functionalities can be found in the SciaL1C Command-line Tool Software User Manual.

Features include:

  • List all measured states on a Level 1b product
  • Extract data sets from a Level 1b product – selecting on:
    • measurement time
    • geolocation
    • data set type (e.g. Nadir, Limb, Monitoring)
    • refined selection options within a data set (see below)
  • Perform Level 1b to Level 1c processing:
    • apply all default calibrations, or
    • apply only specified calibrations.

Selection options within a data set:

  • Extract data containing a specific SCIAMACHY Measurement Category
  • Extract data from user-specified clusters (i.e. spectral ranges, this requires knowledge of the SCIAMACHY cluster configuration available from SOST website.
  • Extract PMD measurements
  • Extract fractional polarisation values.

Selection of calibration options:

No calibration – do not apply any calibration step (DEFAULT)
0 =  memory - application of memory effect (channel 1-5) and non-linearity (channel 6-8)
1 =  leakage - application of dark signal correction
2 =  ppg -  application of Pixel-to-Pixel Gain
3 =  etalon - application of etalon correction (channels 1-5).  Since etalon correction is already applied to the new Level 1b version 8 products, the calibration step is skipped selecting –cal all and –allcal. Option compat permits to force usage of etalon correction.
4 =  straylight - application of stray-light correction
5 =  spectral - application of wavelength calibration
6 =  polarisation - application of polarisation correction
7 =  radiance - application of radiometric calibration
8 =  sun - PMD sun normalisation
mfactor =  mfactor - application of M-factor file. Since degradation correction is already applied to the new Level 1b version 8 products, the calibration step has to be forced with the new compatibility option.
all =  allcal - application of all calibrations (0-8 but etalon)

Installation and syntax example

The SciaL1C software is provided as binary executable file. It only requires to be copied into an appropriate path on your platform (for example /usr/bin or some other convenient path which is set in your PATH variable), and to be started launching the scial1c command with proper options (or you may alias to the installation path and tool name with an alias name).

Syntax examples are provided within the Software User's Manual. As an example, to select and fully calibrate all Nadir and Limb data (measurement categories 1 and 2) in SCIAMACHY channel 3, select option: –cat 1,2 –nadircluster 17,18,19,20,21,22,23  –limbcluster 13 –allcal

Input data

SciaL1C version 3.2 is designed in accordance with the SCIAMACHY operational processing for Level 1b baseline version 8.

Download a sample Level 1b version 8 product: SCI_NL__1PYDPA20020802_193334_000060272008_00157_02215_0000.N1 (316 MB)

md5sum 6f74ff1bd2105ee965933bd3844ba1bc

The entire SCIAMACHY Level 1b version 8 dataset, resulting from the latest full-mission reprocessing campaign completed in 2016, is available to users via Fast Registration. Details are available from the SCIAMACHY Products Information page.

M-Factors are used for the correction of instrument degradation affecting the light path. Starting from SCIAMACHY Level 1 processing baseline version 8, M-Factors are already applied to the Level 0-1b processing step and enclosed into the Level 1b products. The external input of M-factor files (provided by the University of Bremen) is thus no longer required.