Program - 95
Don Schukraft, Certified Consulting Meterologist, Weather Network, Inc.
|A stubborn high-pressure ridge blocked Pacific storms from
scouring pollution out of the Sacramento Valley during the fall of 1995. The result was a
very stagnant weather pattern and the least amount of acreage burned for straw management
since the inception of the burning program in 1981.
Ironically, the fall burning period was the longest on record - running 80 days from September 15 to December 3. Growers burned a total of just over 98,200 acres. This compares with 113,000 acres the previous year. The daily average of rice acres burned dropped from nearly 2,000 acres in 1994 to just over 1,200 last year.
The largest acreage burned on any one day was 7,250 on December 1. On only three other days did total acreage burned exceed 4,000 acres: 4,500 on October 11, 4,400 on November 9 and 5,900 on November 21.
There were a total of 22 "no burn" days declared last fall. In addition to the official no burn days, there were an additional eight days in which prunings only were recommended for burning. On these days a few isolated rice fields were burned. The combination of these restricted days gave growers only 60 percent of the fall burn period to do any significant field burning.
Air Quality Monitoring
Air quality as measured by the .coefficient of haze' (COH) was not very good last fall. The COH was quite high throughout much of the fall burn period. A reading of 3.0 or greater, in combination with an air inversion strength of 17 degrees or higher, triggers a no burn day. There were 41 days last fall when the COH was 3.0 or greater. It was predominantly on these days, however, when burning was not allowed or was allowed in very small allotments.
Weather Network meteorologists note that high COH readings are indicative of very stagnant air flow. All pollutants, including emissions from automobiles and industrial sources, are trapped in the valley under these conditions. There is little correlation between rice field burning and the dirtiest air quality days in the Sacramento Valley air basin.
On the days when COH readings were the highest last fall, no rice fields were being burned. Specifically, on November 14 and again on November 29, both no burn days, the COH reached highs of 4.90 and 5.47 respectively. The day prior to the 5.47 reading was also a no burn day.
Complaints regarding rice straw burning are not necessarily a good indication of the success of the program. There were a total of 138 complaints logged during the fall burn. On October 16 smoke from one burn inundated the Marysville and Yuba City areas, resulting in 28 complaints that day. A meeting of all groups participating in the bum program met the non day to discuss the situation and ways to prevent future occurrences.
The eyes and ears of the fall bum program are the Automated Meteorological Observing Stations (AMOS) strategically located throughout the Sacramento Valley. Weather Network person- nel visited most AMOS sites in late August and early September to check sensors, datalogger, radio and modem. Rain gauges were upgraded at several weather stations and added to others.
A telephone line was installed at the Oroville weather station to ensure data reception from this valuable site. Other stations with telephone access are located in Woodland, Chico and the Sutter Buttes. Remaining stations are accessed via radio transmissions.
In addition to these hardware improvements, computer software up- grades were made at eight key stations (Chico, Artois, Maxwell, Biggs, North Yuba, Lincoln, Natomas and Woodland). The frequency of data output will increase from hourly to every 30 minutes. This change should help provide more current weather information to reduce or eliminate problems caused by sudden weather changes.
Public pressure, more stringent agricultural burning rules and a conservative approach to acreage allocation continue to influence management of the fall burn program. Nonetheless, the program continues to be very successful in minimizing the impact of rice stubble burning on the overall air quality of the Sacramento Valley.