This memo has been sent to alert users of the final production flight-level netCDF data for the NCAR/RAF EC-130Q Hercules aircraft of an error in one of the measurements.
In December 2001, Cynthia Twohy (Oregon State U) discovered differences between CONCF_LPI, FSSP-100 Concentration (all cells), and CFSSP_LPI, FSSP-100 Concentration (per cell). By totaling all the bin values in CFSSP_LPI, one should get the same total as CONCF_LPI. Such is not the case with this data set; instead CONCF_LPI is generally less--up to about 8% at the highest concentrations.
Upon analyzing this descrepancy, RAF found that a correction equation from Darrel Baumgardner was applied to the CFSSP_LPI calculation but omitted from the CONCF_LPI calculation. To obtain a correct value for CONCF_LPI, one needs to sum up all the values in CFSSP_LPI and use that total instead.
Because the data are recoverable within the data files, RAF is not planning to reissue a "corrected" data set at this time.
RAF Data Manager
NCAR/EOL/RAF