Data Quality (new)
Gross errors in energy flux monthly means are due to severe maintenance problems, instrument and data acquisition system failures and/or data processing mistakes. They are systematic or random. They distort the result of any data analysis and must therefore be detected, for instance by quality control procedures (QCPs). Values suspected of being erroneous by a QCP are flagged. A flagged value is checked against its datasource and is duly corrected if a typographical error occurred. No other corrections are applied to the values, since only the station scientist is in a position to give a correct answer to the problem of definitively indentifying and possibly correcting erroneous values.
Currently, QCP No.1 ("physically possible" value test) is beeing applied to all monthly means. The resulting quality flag is given together with each value in the energy flux file for download. Monthly means of energy balance components within the intervals in the following table are considered as being correct. In this table, toa(l,m) is the solar radiation at the top of the atmosphere calculated for each integer latitude and for the 15th of each month. ai(s) and aa(s) are the minimal (maximal) albedo of the surface type at the station. The lower boundaries -120 and -610 W/m2 are estimates, such that the interval is wide enough not to filter out values measured in extreme climates.