Agricultural Burn
Program - 93



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Don Schukraft, Certified Consulting Meterologist, Weather Network, Inc., Chico, CA

The Agricultural Burn Program is a strong affirmation of the California rice industry's commitment to the air quality of the Sacramento Valley. Through an extensive network of computerized air monitoring stations and the application of meteorological science, the program continues to prove itself an effective method of managing increasingly limited burning of rice straw and stubble. Last year saw the legislatively mandated phase down in allowable acreage burned increase to 20 Percent; in 1994 it will be 30 percent.

Burning Summary

The 1993 Fall Bum will be remembered as a year when weather and practices in releasing acreage for burning resulted in the lowest total acres burned since the program started in 1981. A total of just under 108,000 acres were burned between September 15 and November 30. That compares with 165,000 the year before, a 35 percent reduction.

Five days accounted for 41 percent of the acreage burned, and only one of these, Nov. 22, was more than 10,000 acres. There were 18 no burn days; three of which were revised to allow limited burning. The daily average acreage burned fell to its lowest level ever: 1,418 acres.

In spite of the fact that fewer acres were burned on fewer days, citizen complaints nearly doubled over the previous year: up to 101. A sizable number of these complaints (38), however, stemmed from a tule burn on the first day of the fall burn.

System Maintenance

Preparation for last fall's burn began in early summer 1993, when personnel from Weather Network visited the weather monitoring sites, nicknamed "AMOS" (Automatic Meteorological Observing Station). Proper operation of each station's sensor array, datalogger, radio and modem were checked.

At the Sutter Buttes site, a telephone line was installed. Weather Network said this step was taken to ensure consistent observations since increasing radio interference have made this important weather station more difficult to reach.

Atmospheric Conditions

Whether it was due to a lack of days with good atmospheric dispersion or just more caution on the part of participants in the ag burning program, very little acreage was burned last fall. In fact, a Weather Network meteorologist said that were it not for a three-day period in late November, less than 100,000 acres would have been burned.

South winds, which are conducive to good burning conditions, were "uncharacteristically rare" last fall, while north winds were about normal. The meteorologist also noted that the main difference in atmospheric conditions last year was the variable winds that occurred one out of four days - more than double typical fall conditions.

On A Clear Day

To borrow from a popular song: On a clear day they were probably burning a rice field somewhere. Again, the ag burn program is proving its worth in working with nature to optimize burning and also to demonstrate that other forces are at work contaminating Sacramento Valley air. The highest Coefficient of Haze (COH) readings were associated with days when little or no agricultural burning was allowed. Conversely, days with high acreage burned coincided well with periods of very low COH readings. "This strongly suggests that the program continues to be very successful in minimizing the impact rice straw burning has on the air quality in the valley, Weather Network reports.

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