ACE SWEPAM/SWICS mreged solar wind proton data release notes:

These are cumulative release notes. As new data are released or old
data are reprocessed, this file will be updated.

Imporant Note: Please also read the release notes for the SWEPAM and
SWICS individual Level 2 data sets, available at
http://www.srl.caltech.edu/ACE/ASC/level2/swepam_l2desc.html
http://www.srl.caltech.edu/ACE/ASC/level2/ssv3_l2desc.html

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March 17 2008:

Initial release. This data set consists of 12-minute averaged solar
wind proton data from SWEPAM, with gaps in the density, bulk
speed, and temperature data filled in using SWICS data, if
available.

Note: the SWICS proton data are NOT available separately from this
merged SWEPAM/SWICS data set.

The SWEPAM Alpha/proton ratio and the SWEPAM vector velocity are
included in this data set, but gaps in these data are not filled with
SWICS data.

Spacecraft position vectors are also included, in GSE and GSM
coordinate systems.

January 17 2010:

New release, with improved SWICS data processing...test version.
Proper release notes TBD.

March 11 2013:

Data update delivery for 2009-2012. This delivery product was 
generated with version 2.0 of the SWICS auxillary channel data 
processing software. No major changes to the data processing
method. Software improvements in V2.0 include:
   Improved efficiency in algorithm implementation
   Improved automated test cases
   Improved design
   Updated file formatting and meta data section

In addition, the following should be noted about the SWEPAM
averaged data:
   1. Each data entry is 12 minutes of averaged SWEPAM data
   2. There are no data entries when SWICS data is not available
   3. The spacecraft position vectors are not averaged or
       interpolated. They correspond to the position at the
       start of a 12 minute period
   4. The spacecraft position vectors can have a time offset of
       up to 64 seconds