Adjust Daily Temperature Data

Description

Historical climate studies have adjusted daily temperature data relative to a homogeneous reference series (cf., Jones and Lister 2002; Moberg et al. 2002; Vincent et al. 2002). This tool first calculates monthly averages of the daily temperature data and then compares these averages with the monthly data from the homogenous reference series. This comparison yields a correction value that can then be applied to the daily data in one of two ways. The first is a straight-forward adjustment on all daily data for that month. For example, if the average daily data are 0.3 degrees C cooler than the homogeneous monthly data in January 1900, then all daily temperature values in January 1900 are increased by 0.3 degrees C. This method can introduce discontinuities at the beginning and end of each month, so the second way the daily data can be adjusted is by interpolating between the monthly adjustments using the 15th day of each month as the "center point." For example, if the daily data are 0.3 degrees C cooler in January 1900 and 0.2 degrees cooler in February 1900, then the daily temperature on 15 January are increased by 0.3 degrees but from 16 January to 15 February, the adjustments on the daily temperatures gradually approach 0.2 degrees C. Obviously, interpolation cannot be performed during the first half of the start month or on the last half of the end month due to the lack of data. Thus, HOB Tools will simply adjust these data by the derived monthly correction value.

Output Data
The output file specified by the user (see "Output" section below) contains the adjusted daily temperature data. An additional file is also output with a name similar to output file specified by the user except with the word "Adjustments" appended to the end of the name. This file contains the monthly adjustment values. Interpolations between these adjustment values were performed on the output data if requested by the user.

Daily Temperature Input

Daily Temperature Data File
Select the daily temperature data to analyze by clicking on "Browse" and navigating to the proper file.

Daily Temperature Input Data Format
Year / Month / Day / Data

Each "/" is a tab (i.e., data should be tab-delimited). Missing Data should be denoted as "-99", and should be in the same units as the "Monthly Temperature Data File" selected below. In addition, these data should start and end at the same time as the "Monthly Temperature Data File" selected below (e.g., if the "Monthly Temperature Data File" starts on January 1900, then the "Daily Temperature Data File" should start on 1 January 1900).

Start Row
This input is the row number where the main data to be processed begin in the daily temperature file selected above. An example of how row numbers are entered is shown in Figure 2 located in the Running HOB Tools topic.

Adjustment Type
Select whether interpolation should be used to adjust the daily temperature data relative to the monthly reference series.

Monthly Reference Series Input

Monthly Temperature Data File
Select the monthly temperature data to analyze by clicking on "Browse" and navigating to the proper file.

Monthly Temperature Input Data Format
Year / Month / Data

Each "/" is a tab (i.e., data should be tab-delimited). Missing Data should be denoted as "-99", and should be in the same units as the "Daily Temperature Data File" selected above. In addition, these data should start and end at the same time as the "Daily Temperature Data File" selected above (e.g., if the "Daily Temperature Data File" ends on 31 December 2008, then the "Monthly Temperature Data File" should end with December 2008).

Start Row
This input is the row number where the main data to be processed begin in the monthly temperature file selected above. An example of how row numbers are entered is shown in Figure 2 located in the Running HOB Tools topic.

Output

Output File
Select the file where the numerical results will be stored.

Output File Header
Information entered here will be output in the first line of the output file.