Reprocess:SGP BLC reprocessing status

The BLC data was the subject of a reprocessing 
effort last summer in support of the ARSCL
effort.  As a result three distinct windows of
data with varying levels of processing have been
created.

1) 940401-961031 - not reprocessed.  This data
   has a 110m offset in the reported cloud base
   height (see P980831.1).  No sgpblcprofC1.a1
   data available.  Reprocessing required.

2) 961101-990630 - reprocessed.  The 110m offset
   was corrected in this data and the blcprof
   data were created.  This data still contains
   the defunct field 'operational_state' which
   was determined to be useless and was removed
   in later data.  This data will be reprocessed
   at a later date to remove the operational_state
   field to create a continuity with the current
   data.

3) 990701-present - reprocessed/processed without
   'operational_state' field.  Offset has been
   corrected or no longer exists.  The format of
   this data is the target for the previous two
   data windows.

Reprocess 940401-990630 data to apply offset corrections, 
create sgpblcprofC1.a1 data, and/or remove 'operational_state' field.

• Base height of second cloud detected with threshold algorithm(cloud2)
• Base height of third cloud detected(cloud3)
• Base height of lowest cloud detected(cloud1)
• Base height of third cloud detected by Klett method(kcloud3)
• Base height of lowest cloud detected by Klett algorithm(kcloud1)
• Base height of second cloud detected with Klett algorithm(kcloud2)
• Operational state of the BLC(operational_state)

• (Raw data stream - documentation not supported)

• Base height of second cloud detected with threshold algorithm(cloud2)
• Base height of lowest cloud detected(cloud1)
• Base height of third cloud detected by Klett method(kcloud3)
• Operational state of the BLC(operational_state)
• Base height of second cloud detected with Klett algorithm(kcloud2)
• Base height of lowest cloud detected by Klett algorithm(kcloud1)
• Base height of third cloud detected(cloud3)