Reconstruct Precipitation

Description

This tool reconstructs precipitation amounts or precipitation days on a monthly basis using a series of stations input by the user (e.g., Burnette and Stahle 2013a).

Discussion of the Output Data
If "Use Consistent Number of Stations" is not checked (see "Reconstruction Input" section below), then all stations with data available for a given month are averaged together into one monthly precipitation amount or precipitation day count. The interquartile range of the precipitation observations is used as a measure of the error in the reconstructed value. These errors can only be calculated when two or more stations are averaged. If only one station is available, then a “-99” will be output for the error.

If "Use Consistent Number of Stations" is checked (see "Reconstruction Input" section below), then HOB Tools will calculate the precipitation reconstruction in the following steps:

  1. The average precipitation value using all stations is found.
  2. Absolute values of the difference between each station and the average calculated in step 1 are found.
  3. The user-specified number of stations with the smallest differences are averaged together and output (i.e., only the user-specified number of stations closest to the network average are used in the reconstruction).

A “-99” will be output if the number of stations available for the monthly calculation is less than the "Number of Stations to Use" (see "Reconstruction Input" section below). Errors are calculated in the same way as above, but only the stations used will be involved in the calculation of an error value.

Input

Precipitation File
Select the precipitation data to analyze by clicking on "Browse" and navigating to the proper file.

Input Data Format
Year / Month / Station 1 / Station 2 / … / Station N

Each "/" is a tab (i.e., data should be tab-delimited). Station 1 through Station N are the names of the individual stations. Only monthly precipitation data are allowed, and all columns must be filled with observations. If a station does not have observations during the particular month, then a “-99” should be entered indicating a missing value.

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

Number of Input Stations
Enter the number of stations that will be used to create a monthly precipitation reconstruction.

Precipitation Data Type
Select the format of the precipitation data. Amounts are selected by default.

Reconstruction Input

Use Consistent Number of Stations
By default, HOB Tools averages all available stations to obtain a reconstruction of precipitation. However, changes in the number of stations over time and poorer data quality at one station relative to the rest of the network could potentially bias the reconstruction. Check this option to force HOB Tools to always use a consistent number of stations, and specify the number to use under "Number of Stations to Use" below.

Number of Stations to Use
If "Use Consistent Number of Stations" is checked, then this field will be enabled. Enter the number of stations HOB Tools will always use to obtain a reconstruction of precipitation.

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.