Cluster Active Archive Activities

The Cluster Active Archive (CAA) is a pioneering project which aims to make available to the scientific community a full set of data products which are of publishable quality from all the instruments onboard the Cluster spacecraft.  Imperial College is involved in the project by providing calibrated data products from the Fluxgate Magnetometer instruments on each of the spacecraft.  These data products are described in more detail below.

Data products

The three primary Fluxgate magnetometer data products are magnetic field data at three different time resolutions:

• Full resolution: 22 vectors/sec normal mode or 67 vectors/sec burst mode

• 5 vectors/sec

• Spin averaged

All three data products are calibrated using the same calibration file which is valid for the period of one orbit period from perigee to perigee.

There are several auxiliary data products which are listed below:

• Data gap file(lists gaps after data processing)
• Validation gap files(lists gaps introduced at validation stage)
• Calibration accuracy files
• Static experiment caveat file
• Instrument caveat files

Calibration files are also provided and each one is valid for the period of one orbit.  In addition to these, there is a plan to generate calibration refinement files which will make it possible to take account of changes in calibration which occur on a timescale shorter than an orbit.

Archiving procedure

• Calibration analysis: This step requires the most substantial amount of work and more details can be found on the calibration webpage.
• Data processing: The bulk of the data processing is done using the standard data processing software.  One additional step is required which outputs the data in the Cluster Exchange Format(cef) which has been developed for the CAA.
• Validation: The validation is done visually on the 5 vector/sec data.  Despite a certain amount of automation which has been introduced to find data spikes, this is a time intensive step.
• Submission: Once the data have been produced in the correct format they are submitted to the CAA for ingestion into the archive system.