Date: April 17, 1997
System: Weather Information Management System (WIMS)
Subject: Station start-up and shut-down
Purpose: To provide users with key information for station start-up and shut-down
Contact: Fire and Aviation Management Applications Helpdesk
Problem: The western fire season is quickly approaching. With that in mind, it is time to start collecting daily weather observations. Enclosed are a few steps to take to help provide accurate NFDRS outputs. These tips apply to stations that are operated year around, as well as seasonal stations.
1. Each spring, approximately 30 days before setting the herbaceous state to GREENUP, set the Herbaceous State to PREGREEN. This will signal the models that GREENUP is approaching. Make sure observations are entered for each day after setting the Herbaceous State to PREGREEN.
2. Once observed GREENUP has started set the Herbaceous State to G for GREENUP. Notice the GREENUP date has changed to reflect that the Herbaceous State was changed.
WIMS will calculate the daily observations and produce the NFDR Outputs daily. As the models dry the Herbaceous State will change from G for GREENUP to T for TRANSITION when the herbaceous moisture drops to 120%. When the herbaceous moisture drops to 30% to the herbaceous state changes to C for CURED. Curing of the herbaceous model does not affect the woody model.
3. After the growing season has ended and the herbaceous plants are dormant or frozen, depending on the station locations, set the Herbaceous State to F for FROZEN. The FROZEN state shuts off the live fuel moisture for both herbaceous and woody.
4. Make sure that GRASS is correctly defined as perennial or annual.
5. If GREENUP has already occurred and the station catalog does not reflect the current greenup date (ie. greenup occurred on 4/1 and today is 5/1 and this is the first OBS for the year.):
a. Backdate the GREENUP date on the ENFDR screen by setting the Effective Date to the desired GREENUP date (4/1), change the Herbaceous State (HS) to G for greenup, enter the GREENUP date in the HERB date. Save the changes (F1). Note: The Effective Date, Greenup Date and Herb Date should all be the same date (4/1).
b. Before entering the first OBS, go to the ENFDR screen, and set the effective date to the current date (5/1). Set the herbaceous, woody, 100 hour, 1000 hour and x-1000 hour values to the values you want today's NFDRS calculations to be based on. (Check your local neighborhood to get a feel for what numbers might be reasonable). Save the changes (F1). Enter today's OBS.
If GREENUP occurred several weeks previously and you have been entering observations daily before or since that time, and you have not signaled GREENUP in the station catalog, you will need to backdate the Greenup date as in step 5b and the perform a RECALC from the GREENUP date through the current date to allow the live fuel moisture model to respond to the greenup signal. Once the RECALC has been completed, it is a good idea to check the daily change in the live and dead fuel moisture values using the DIDX screen and viewing all outputs since the GREENUP date using the "greater than" functionally of the date field (i.e. >01-Apr-97). The live fuel moisture values should start a steady increase on the day following GREENUP.
6. If GREENUP occurred several weeks ago at a year-round station, and the station catalog did not go through the FROZEN and or PREGREEN phases (ie. the herbaceous stage was taken right from CURED to GREENUP and the observation entry was continuous), the station should be RECALCed from the actual greenup date to current. To accomplish this task, the following steps should be followed:
a. From the ENFDR screen, make the Effective Date equal to the GREENUP Date, change the Herbaceous Stage to FROZEN, set the HERB date equal to the GREENUP date and Effective Date. Save the changes.
b. From the EOBS screen, RECALC all the OBS from the old GREENUP date (the current FROZEN date) to the current date.
c. Return to ENFDR screen and make the Effective Date equal to the original GREENUP date. Change the Herbaceous State (HS) from "F" for FROZEN to "G" for Green. Set the Herb Date and the Greenup Date equal to the original Greenup Date. Save the changes.
d. From the EOBS screen, RECALC all the OBS from the Greenup Date to current. Check the trends in the fuel moisture outputs as described in 5.b.
1. Be sure to set the season codes accordingly.
2. Greeness factors for Herbs and Shrubs should also be entered. Get these values from on the ground measurements or see the WIMS USER GUIDE for definitions.
3. Make sure that GRASS is correctly defined as perennial or annual.
4. Make sure that SHRUB type is correctly defined as evergreen or deciduous.
1. KBDI. Make sure that the average annual precipitation is entered in station catalog. When starting KBDI for the first time, use a neighboring station as a starting point. If the station has been running all year, go back and make sure that KBDI reached zero at the conclusion of a long wet period. If zero has been reached and the average annual precipitation has been put into the station catalog, the KBDI value should be accurate.
Thanks: Russ Gripp, R5, and Sue Petersen, WO
**End of TechNote 97-05**
Changes were made to this page 12/06/99.