CIPS Data Overview
Last updated 20090526

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The CIPS instrument [McClintock et al., 2009] consists of four wide-angle cameras that measure 265-nm radiation scattered by the atmosphere over a wide range of scattering angles. The fundamental measurement is an albedo, which is the measured radiance divided by the input solar irradiance. On each orbit, around 27 images are acquired with each camera over the summer pole, between the terminator and about 40 degrees latitude on the sunlit side, with overlapping successive images.

The CIPS data products are listed below; more details can be found in documentation specific to the individual levels (see the highlighted text).CIPS data for levels 2, 3, and 4 are currently available online. It is anticipated that users interested mainly in a qualitative picture of where/when CIPS observed PMCs will be most interested in level 3 data. Users interested in quantitative mapping of the PMCs will be most interested in level 2 data, and users interested in cloud parameters (frequency, albedo, radius, ice water content) will be most interested in level 4 data.

Data Products:

Level 0: Raw, uncalibrated images. Images are binned on-chip to 170 x 340 pixels (cross track by along track) for each camera. Effective spatial resolution varies from around 2.4 km x 2 km (nadir) to around 4.5 km x 3 km (forward & aft cameras).

Level 1a: Calibrated and geolocated albedo. NetCDF files contain all images from a single camera over one orbit, so there are 4 files per orbit (one per camera).
Documentation -->

Level 1b: Map-projected albedo calculated from level 1a at 5 km x 5 km resolution. One NetCDF file per orbit. These files register all measurements of a single location into data "stacks" to facilitate analysis of phase functions (albedo vs. scattering angle).

Level 1c: Same as level 1b, but with the Rayleigh scattering background subtracted. One NetCDF file per orbit.

Level 2: PMC albedo over a single orbit, calculated by merging overlapping images from level 1c. Cloud albedo is normalized to 90 degree scattering angle and nadir view. One NetCDF file per orbit; 5 x 5 km resolution.

Level 3a: Daily maps of combined orbits from Level 2. 5 x 5 km resolution. One .png file per day.
Documentation -->

Level 3b: Level 3b: Movies of daily maps for an entire PMC season. One MPEG4 file per season.

Level 4: Cloud presence retrievals, albedo, ice water content and particle radius. For convenience, this data is available in multiple formats:

• 15 km x 15 km resolution orbit strips. One netCDF file per orbit. This data is available at http://aim.hamptonu.edu/sds/. To access more than a month's worth of these netCDF files, please contact aim.sds@lasp.colorado.edu with details of your needs.
  
  File reading tools and additional documentation can be downloaded by clicking the links below:

  Level 4 Documentation
  CIPS Tools

• Level 4 Season Summary Files. These are ASCII text files that contain the primary CIPS level 4 retrieval products and associated auxiliary data for each orbit over an entire PMC season. Data are binned in 5-degree latitude bins. There are nine files for each season, which are described in more detail in the level 4 season summary file documentation, and which can be accessed from the level 4 data tab.
  
  Note: Improved flatfield corrections have recently been incorporated into Level 4 Summary Files. If you have Summary Files that are older than July 30, 2009, please download the most recent files.
  
  
• Common Volume (CV) Season Files. These are ASCII text files that contain the primary CIPS level 4 retrieval products and associated auxiliary data in the CV for each orbit over an entire PMC season. Data are given for each individual pixel within the CV. There is one file per season, which is described in more detail in the CV season file documentation, and which can be accessed from the level 4 data tab.

Reference: McClintock, W.E., et al., The cloud imaging and particle size experiment on the Aeronomy of Ice in the Mesosphere mission: Instrument concept, design, calibration, and on-orbit performance, doi: 10.1016/j.jastp.2008.10.011, 2009.

For questions or comments, please contact Cora Randall (randall at lasp.colorado.edu).