Performance of RS92 GRUAN Data Product Version 2

The current data quality status refers to the processed Vaisala RS92 data. Currently we have three quality levels and all data we have received are ranked within these three categories:

Approved (green):

The raw data have been successfully processed and the processed data has passed all quality checks. An approved measurement is considered a valid GRUAN observation, and it is available at NCDC (Link to the GRUAN FTP Server).

Checked (yellow):

The raw data have been successfully processed, however the processed data failed the subsequent quality check. A common reason for failing the quality check is that the estimated uncertainty exceeds the uncertainty specified by the manufacturer. Another common reason is that measurement values during ground check are outside the expected range. Checked soundings often have failed multiple quality checks. Due to the requirement to provide reference quality measurement data, GRUAN quality checks are stricter than the quality checks for operational soundings. As a consequence, soundings that failed the GRUAN quality checks are not automatically worthless, but these data should not be used for long term climate observations as these data might affect the homogeneity of a long term data record. Checked soundings are available upon request at the GRUAN lead centre (email to gruan.lc@dwd.de) Please provide the following details: station, time range, motivation/project.

Rejected (red):

Rejected data could not be processed. Reason may be corrupt data, or bugs in the processing software. Soundings for which the prescribed operational procedure was not followed will also be rejected. This particularly concerns the ground check, because missing or improper ground checks lead to systematic biases in long term data records, which can not be corrected for afterwards.