Model Inputs
Date Comparison
Model Output
INTRODUCTION: This phenology model/degree-day calculator uses weather data to calculate degree-days, also known as heat units that are used to estimate development of many organisms, such as insects and plants.
This app is essentially a wrapper around the newly re-designed, mobile-friendlier, online model/calculator at: uspest.org/wea - USPEST.ORG (home page). The numerous models served by this app are all driven only by daily maximum and minimum temperatures, using one of many different degree-day calculation formulas, many of which are described at this UC Davis IPM website. Note that this app requires wifi or cellular connectivity and will not work in airplane or off-line mode.
INSTRUCTIONS FOR USE: We split this app into tabbed
sections in 1 or 2 rows near the top of the page. Use the tabs
from left to right. This introduction is in the first tab "Intro".
Notice while using this app, if you see the
icon, click on it to access more explanatory information via a pop-up help window.
The Station Tab
The second tab, "Station", allows selection of a weather station needed
to run the models from a database of around 29,000 weather stations from hundreds of
weather networks throughout
the U.S., with more in Canada and Mexico and some other surrounding places. Most of our
weather data comes from Mesowest in Utah. We also
have data from participating agricultural weather networks (scroll to far bottom of this
page and read the fine print to see some of these).
To find a weather station, enter a known weather station code (e.g. ARAO), a zip code, or a city and state abbreviation. Then click on the button "search for stations" to find 1 or more expandable lists (click on "+" sign to expand, "-" to contract) of the 4-8 nearest stations. Once you click on a station code and you see the text "Selected station:" with a station code and a place name, then you have selected a weather station. Be warned that not all weather stations have valid data so you may need to return to this step!
You may also click on the (MAP) link to open a Google map selection option. With this, you can zoom in, zoom out, pan, and click a station pin to select a station.
The Model Tab
Once you have a station selected, click on the next tab, "Model". This tab
begins with selection of a model category. For example, all models (ca. 115 models), insects (ca.
68 models), weeds (5 models), plant diseases (5 models), and crops (32 models), plus
various combinations based on other criteria, such as invasive insects (22 models),
apple and pear (16 models), stone fruits and nuts (12 models), etc.
see current list.
Note that all categories include "generic degree-day calculator" (see below) as the first option. Also note that none of these models are driven by hourly weather, only by daily max and min temperatures. You may want to try MyPest Page at USPEST.ORG for hourly driven (most plant disease infection risk, plus other), models (not mobile-responsive however).
The end date is usually not critical (as long as it is not set too early), and we have changed the graph output so that it only extends a couple of days beyond the last date of a model event.
Once a model is selected, you may scroll down to review the model information, helping you confirm that you have selected the appropriate model for your needs. Model inputs include information such as thresholds, region of known usage, model events, and links to extension pages and model source information. Many of the 100+ models were derived from one or more scientific publications and combined into a working model by OSU IPPC in the form of a spreadsheet converted to PDF format.
Notes:
1) This forecast option will not be available if you run the model for prior years or you set the
end date earlier than the current date.
2) All available forecast options will be used as future forecasts in the graph output (if the model
end date is 6+ days later than the current date). See example image:
3) Three of these forecast options (past 1 year, 10- and 30-year averages) will
be displayed as "comparison lines" versus current weather station observations if you run
a model setting the end date earlier than the current date.
See example image:
Celsius (temperature scale) Option
This calculator may be run in celsius or Fahrenheit. Brought back by popular demand!
Lower threshold
The lower developmental threshold is an approximate temperature below which, development has slowed
to zero. This value varies depending on the type of organism and even the specific species. Usually
the lower threshold is determined using laboratory or field data, and may be available in the
scientific literature.
Upper threshold
The upper threshold is often not known or well studied. It is recommended that you
use whatever guidelines are available for your organism. Otherwise just leave this at the default
value (currently set at 130F).
The Output Tab
Once the Station and Model have been selected, click on the "Output" or "Graph" tabs
back at the top of the page to see model predictions or output. The default "Output"
consists of an expandable
repeat of the Model Inputs, expandable Date Comparison (see below), and expandable table of
Model Output with
predicted dates (first column) and model events (last column). In between, are the daily max and min
temperatures, rainfall, degree-days for the day, and the cumulative degree-days from the start date to
indicated date. This "collapsed" table includes only rows for dates when a model event occurs.
Check Data QA (Quality Assurance)
Click "show full table" to expand to the full
table (rows for every day from the start to end dates) to review ALL of the temperature data
used to drive the model, not just the small number of days when a model event occurrs. This is
very important because, as mentioned above, not all weather stations have good data, so please examine
the FULL set of temperatures used for the model, and watch for QA tags such as "Px" that
indicate that the
data was missing or in error, and a method ("Px" indicates PRISM map interpolation was used) was
used to estimate the data.
If you see numerous tags like these, you may
want to run the model using a different nearby weather station (click on the "Station" tab again
and expand the Google map to see nearby station locations). If only a few of these tags occur, then you
may not expect much error in the degree-day accumulations (use at your own risk).
The QA column is also where a forecast is indicated, e.g. "Nm" reflects the selection of the NMME forecast. Click on the tag links to further investigate how the temperatures were estimated or forecasted.
Date Comparison
The Date Comparison expansion option allows you to see how, (for the current model inputs
including the start date, threshold temperatures, and calculation method), the Current year degree-day
accumulation compares to Past year degree-days, in particular the prior 2 years and
to the 30-year Normals. For example (in the figure above), the 2018 to-date degree-day accumulation of
1377 DDs was reached 23 days earlier in 2017 and was reached 2 days later in
2016. That degree-day total was never reached using 30-yr Normal data. (note this is a slightly
contrived example as the start date was Sept 1, 2018, but this could apply to fall-planted vegetables
for example).
The Graph Tab
The Graph presents model output as a graph, with dates on the x-axis and cumulative
degree-days on the y-axis. Predicted model events are displayed both with reference to
the degree-days as horizontal
lines of text, and with reference to dates as diagonal lines of text starting along the x-axis.
Close-together events may overlap and be difficult to read. To help overcome this issue,
the graph is interactive and allows
for zooming in on only the portion of the output you wish to see. It will also display the data when
you hover (lightly touch) a graph line or point, and has the option to turn off a data line by
clicking on the legend item at the bottom of the graph. The
options for displaying multiple forecasts are discussed above under Forecast options.
Degree-day model options not included in this version
To help simplify this version of the calculator for use on mobile devices, we have turned off
two features available in an earlier version, at
uspest.org/dd/model. These include 1) Multiple start
dates (added for vegetable phenology models), and 2) Daylength calculations (helpful for species that
are photoperiod-responsive such as insects that use daylength to trigger diapause).
CREDITS
This app was funded primarily by a USDA NIFA CPPM EIP grant to support IPM at the state and regional
level, and by the Oregon State IPM program at IPPC. Other
sources of support include other NIFA funded grant programs, including the Western IPM Center, and from
USDA APHIS PPQ support.
Location search using place names (geo-coding) by OpenCage, using data © OpenStreetMap contributors. IP address search uses GeoLite2 data from MaxMind.
That's all the necessary input. From here, you can study the model details below, or go to the "Output" and "Graph" tabs for your model output.
All data provided "as is" and users assume all risk in its use - see full disclaimer. All NWS derived data is not subject to copyright protection.
This app is produced by uspest.org at the Integrated Plant Protection Center at Oregon State University with support from the USDA National Plant Diagnostic Network, The OSU Agricultural Experiment Station, various USDA CSREES/NIFA grants, USDA SARE, USDA RMA, and USDA IPM Centers - Western Region. Climate map data provided by OSU PRISM Group, real-time public weather data provided by U. Utah Mesowest and other networks including WSU AgWeatherNET, AGRIMET, CPS Adcon Networks, IFPNet Automata, California CIMIS, California PestCast, and others. Geo-coding (location search using place names) by OpenCage, using data© OpenStreetMap contributors.
Previous versions online since May 16, 1997; this is app version 0.93, updated 28 Dec 2018
Contact Len Coop at coopl@science.oregonstate.edu or 541-737-5523 if you have any questions about this program.