MainScreen

 

SolarCalc Help Screen

 

Overview

This program is designed to estimate the hourly incoming solar radiation

at a particular field site.

 

The necessary inputs are:

  1. Latitude, longitude, and elevation of the field site.
    1. Latitude is in degrees: latitudes south of the equator are negative, with north positive.
    2. Longitude is in degrees: longitudes west are negative, with east positive.
    3. Elevation is in meters

 

  1. Optionally, daily weather data. See below for format requirements.

 

Main Program Input Screen:

 

Entries for the latitude, longitude, elevation, and year to model are performed in this initial dialog box.

 

Selecting "Search US Zip Code" will enable the user to search for latitude/longitude by enetering the US zip code in the pop-up dialog window:

 

After the zip code is found the corresponding latitude and longnitude are placed in the text entry boxes.  The name of the town and state are also displayed in the dialog box between the latitude and longitude labels to ensure proper selection.

 

Selecting "Completed"  conitnues the data entry with the Weather Data entry described below.

 

Selecting "Help"  brings up this help information.

 

 

Weather Data:

 

The next dialog box will ask if you wish to select the daily weather file:

 

 

 

Selecting YES will bring up an Open File dialog so that you can select the yearly weather file.

 

 

Selecting NO will run the simulation without site specific weather data (not recommended).

Without the daily weather – there will be no correction to the recorded weather at the site.  This will result in severe over predicting of the solar radiation by the model.

 

Selecting CANCEL will exit the program.

 

Daily Weather File Format

Day of year, min. air temp, max. air temp, rainfall

Each day of year is on a separate line, missing values can be skipped.

 

 

 

 

Following the weather dialog the program will prompt you for the output filename.  This is where the modeled hourly solar output will be saved. 

 

 

 

 

The file format is in an EXCEL date compatible CSV file:

 

DATE/TIME, Solar Radiation (W m-2) , delta Temperature, Tao (atmospheric transmistivity = τ)

 

(hourly data)

 

 

The model will display a real time graphical representation of the peak daily solar radiation value as well as a table with the real time calculations (shown below).

 

 

 

 

 

The delta temperature and tao were debugging outputs, but have been left so the user can see the value used for tao in the modeling.

 

 

 

If you have trouble extracting the source code please send an email to spokas@morris.ars.usda.gov and I will gladly send you the *.java files.

 

 

 

Written by Kurt Spokas at the USDA-ARS, Morris, MN 56267

 

 

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