Remark Codes for Air Temperature Data from Argonne National Laboratory

The following codes have been created to identify the origin of the Argonne National Laboratory air-temperature data values. The codes indicate if the data are original or missing, the method that was used to fill the missing periods, and how it has been transformed into the current statistical base if it is from before 1989.

The codes consist of a three-digit sequence in the form "xyz" that describe the origin and transformations of the data values, where:

The "x" code is the "fill" indicator where:

• 0 - original Argonne QA/QC data
• 1 - Argonne data was missing
• 2 - Argonne data was deemed erroneous
• 3 - non-QA/QC data was considered preferable
• 4 - original Argonne QA/QC data may or may not have been OK but was filled due to bad data at another time during the day. This code applies to wind and solar radiation before 1989, and dewpoint during certain periods, which require filling whole days.

The "y" code is the data source indicator for filled or replaced data:

• 0 - no filling or replacement (corresponds to x = 0)
• 1 - by linear interpolation of data before & after
• 2 - automatically filled by MAGIC
• 3 - by use of data from another series
• 4 - not applicable to air temperature
• 5 - not applicable to air temperature
• 6 - by inserting a missing negative sign
• 7 - by extrapolation (for example, 1-2 hours to finish out a day in the dewpoint data when filling whole days)

The “z” code describes either: (a) the transformation used to convert pre-1989 Argonne data to the Argonne-DAT (1989 to present) base, or (b) the data used for filling in the missing periods and the transformation applied in doing so. The former applies when “y” is not 3, while the latter applies when “y” is 3. Two tables of “z” values follow, one for each of these two cases.

I. “z” codes when “y” is not 3:

As a different transformation applies to each period in the data that was determined to be statistically distinct, what is given here is simply the period corresponding to each "y" code. The transformations are described in Illinois Water Science Center files. The period 10-1-81 to 12-31-83 is not included since there is no Argonne data during this period. Other shorter periods may also be excluded for the same reason.

• 0 - no transformation: Argonne-DAT QA/QC data (1-1-89 to present)
• 1 - Argonne-pre70 (1-1-48 to 11-30-70)
• 2 - Argonne-IBM, period a (12-1-70 to 10-31-74)
• 3 - Argonne-IBM, period b (5-1-75 to 7-31-78)
• 4 - Argonne-IBM, period c (9-1-78 to 9-30-81)
• 5 - Argonne-ARC (1-1-84 to 12-31-88)

II. “z” codes when “y” is 3:

Due to the complexities involved in the filling and transformation process, just the different periods are listed here. The methodology is available in the Illinois Water Science Center files.

• 0 - data was not filled or was filled by interpolation
• 1 - Wheaton-College (1-1-48 to 5-31-66)
• 2 - Wheaton-Arbor (6-1-66 to 12-31-88)
• 3 - St. Charles (1-1-89 to present)