Optimum Weather Conditions for Prescribed Burning in the Flint Hills Region

Highlights The subjectivity of landowner decisions in prescribed burning was influenced by solar radiation and relative humidity. Landowners preferred to burn when there was less cloud cover, which promoted O3 generation. Proposed optimum weather conditions will reduce the smoke impact on O3. Abstract. Land managers use weather conditions to determine when meteorological and fuel conditions are suitable for prescribed burning. The objectives of this study were: 1) to characterize meteorological parameters’ sensitivities and identify the influential weather parameters connected to daily fire activities; and 2) to identify optimum weather conditions that are practical for mitigating the smoke impact associated with prescribed fires in the Flint Hills region. Machine learning techniques using random forest (RF) with Shapley additive explanation (SHAP) values and Pearson correlation were used to identify the relative importance of weather variables and their impact on landowner burn decisions in the Flint Hills region based on historic data from 2003-2019. Results showed that less cloud cover demonstrated superior predictive power in landowner decisions for prescribed burning and largely resulted in elevated ambient ozone (O3). We found out that six days per burning season on average provided the proposed optimum weather conditions, where cloud cover ranged from 10+ to 55%. However, 62% of the total burned area occurred when the cloud cover was less than 10+% during 2003-2019. By changing the current burning occurrence to the proposed optimum weather conditions in our study, the probability of 70+ ppb O3 occurrence could be reduced from 35% to 9% on heavy fire days. Keywords: Cloud cover, Optimum weather conditions, Ozone, Prescribed burning.