Weather data

Data from weather stations can be incorporated into the PR41, allowing time graphs to be drawn with environmental data overlaid with soil moisture readings. The are two methods to incorporate the data.

  1. Create a 'dummy' site for the weather station
  2. Enter the data in a separate DWU file for display on the readings screen using a Keydata or Global formula.

Method 1 - Creation of a Weather Station Site

Create a 'Site' for the weather station data. Delete all the depths to indicate that no probe readings will be recorded at this site, but enter a Keydata item for each environmental variable that is being monitored. Users could consider creating a 'Farm' for each weather station, with a new 'Site' for each season

The example below use the Firebaugh weather station, a part of the CIMIS network in California, USA.

From DOS, make a directory for the weather data:

    C:\PROBE> MD C:\PROBE\WEATHER

2 Run the PR41 software, and create a 'farm' for each weather station. In this example for FIREBAUGH :

FullName: Firebaugh Station
Farm Number: 99 (not used at all)
FarmShortName: FBH
Data Path: C:\PROBE\WEATHER

3 If you need to create 'sites' for several years of data, create a standard site using UtilitiesStandardSite, and saved it as CIMIS.CRP>. Set this as the default using Utilities/Defaults.

Default Crop:CIMIS

4 Go to sites level, and create a 'site' for each year. The default settings in CIMIS.CRP> will be loaded as the default, but enter the year as the site number - for 1993 data SiteNum:93

You should now have C:\PROBE\WEATHER\FBHALL.STS> ( the sites screen), and files such as C:\PROBE\WEATHER\FBH93.NPS> which will contain the actual data for the 1993 season.

The environmental data can be entered manually, or it can be automatically posted.

Manual entry

Go to the weather station readings screen, find the next free column and enter the date, time and 'k' for keydata. Then enter the readings in the Keydata area of the spreadsheet.

fig 3 Readings Screen

Automatic Posting

If the weather station has an automatic data logger that can produce a DOS text file output, it may be possible to convert to the Probe software format, for transfer to the readings screen. For details of  PRX> programme contact RSNE attaching a copy of typical output of your weather station (the expor file), and indicate which sensor outputs are required to be posted to the Readings screen.

PRX use import configuration files that can be customised for different loggers and data formats.  These files can be written by RSNE or by the user.

Method 2 - Entering weather data in DWU file

Environmental data can also be entered into DOS files (in DWU format). The advantage of this method is that the data from the file can be used in a keydata formula. For example, if evaporation data was entered in a file called PAN.DWU>, then the Keydata or Global formula:

+PAN.DWU/ProbeDWU

would calculate and display the ratio of crop water use to pan evaporation, which is a measure of the plant 'efficiency'.

Each time new evaporation data becomes available, use a word processor or the MSDOS V5 EDIT programme to add new lines to the end of the file PAN.DWU.

    C:\PROBE> EDIT PAN.DWU

There will need to be a separate DWU file for each environmental variable. The first line in the file is the 'planting' date, in days since Jan 1st, and all following lines are 'days-since-planting', a ",", and the value of the environmental variable - see DWU filesfor a full description.

Note that the Probe software reads the DWU file and interpolates the data. For example if pan data is only measured once per week then a Keydata formula will work out the value of the Pan evaporation on each day of the week assuming that it varied linearly. This could cause a problem if, for example, rainfall is entered in a DWU file.