Difference between revisions of "Grow Degree Calculator"

Revision as of 12:08, 12 June 2017

Grow Degree Calculator application.

The Grow Degree Calculator (GDC) project is based on the WRF Hindcast project and calculates the Grow Degree values for either crops or insects. Users can enter the temperature parameters, location, and start and end dates for the organism of interest. Output includes an image of the total accumulated values over the target sector, a plot of accumulated values over time, and a text report.

Accumulated grow degree values are important for agriculture because it can accurately predict organism behavior. For example, knowing the accumulated grow degree values throughout a season, farmers can say when orchard trees will blossom, or when insects will hatch, and more. Click here to use the GDC application.

Procedure

The GDC application calculates a location's accumulated grow degree value from historical WRF Hindcast data stored on our server. The user customizes the calculation request by entering temperature parameters, location, and run dates. The application determines which sector and data pixel to use, gets historical daily minimum and maximum temperatures, calculates and accumulates the grow degree units over the run dates given for the pixel location.

Calculation of Grow Degree

Links of Interest

Input Form

The input form of the application is divided into three components: temperature, location, and run dates.

Temperature

Organisms (plants and insects) have a range of temperatures in which they can grow. The base input value is the lowest temperature for the organism to grow. Likewise, the upper input value is the highest temperature for the organism to grow. Temperatures values are in Celsius.

Location

Location input requires decimal degree latitude and longitude values. If values are not within the active sectors, error messages will appear in the text report panel of the application. See WRF Hindcast for current operational sectors.

Run Dates

The start and end date specify when to accumulate the grow degree values. Dates are given in the YYYYMMDD format, eg. March 5, 2017 would be 20170305.

Output

GDC Image

GDC Plot

1. Temps (celsius)

Organisms (plants and insects) have a range of temperatures in which they can grow. Example: 5, 30

    base  5
      The base input value (celsius) is the lowest temperature at which the organism can grow.
    upper  30
      The upper input value (celsius) is the highest temp at which the organism can grow.

2. Location (dec. deg)

The latitude and longitude values of the area of interest, in decimal form. Example: 32.25049, -106.74516

    latitude  32.25049

    longitude  -106.74516

3. Rundates (yyyymmdd)

The start and end date specify when to accumulate the grow degree values. Dates are given in the YYYYMMDD format, eg. March 5, 2017 would be 20170305. Example: January 1, 2017; April 6, 2017

    start  20170101

    end  20170406

4. Apply

Run the application with the provided values of Temps, Location, and Rundates

5. 3 tabs: 3.3km, 10km, 30km

Based on the latitude and longitude values provided by the user, clicking on a tab will display the processed accumulated Grow Degree image of the area of interest. All 3 images are 171 x 171 pixels in size but the 'resolution' of each pixel varies in each of the 3.

    3.3km  each pixel in this image represents an area approx. 3.3 km high by 3.3 km wide.

    10km   each pixel in this image represents an area approx. 10 km high by 10 km wide.

    30km   each pixel in this image represents an area approx. 30 km high by 30 km wide.

Clicking on the '+' in the image will 'zoom-in' the image.

Clicking on the '-' in the image will 'zoom-out' the image.

Clicking on the 'house' in the image will restore the image to its initial display size and position.

Clicking and holding down the left button on the mouse enables moving the image.

You should see a small blinking black square in the image. Your latitude and longitude of interest will be inside this square. Use the '+' sign or the wheel on your mouse to zoom in.

If you don't see the small blinking black square it's because the underlying or surrounding area is also black or blackish. In this case move the mouse around in the image and look at the latitude and longitude values displayed in #6 until you have homed in on the desired area.