GIS-TECHNOLOGIES AND MATHEMATICAL SIMULATION TO PREDICT LIGHTNING-CAUSED FOREST FIRE DANGER

Abstract

Context. The components of the geoinformation system for monitoring, forecasting and assessment of forest fire danger caused by thunderstorm activity are developed. Objective of the work is to create an embedded software tool for physically based forecasting, monitoring and evaluation of the probability of forest fire occurrence as a result of the impact of a lightning discharge on a tree trunk. Method. Structural analysis is used to design elements and information flows inside and outside of the developed geographic information system. Mathematical modeling is used to determine the parameters of tree ignition by the cloud-to-ground lightning discharge. Mathematically, the process of tree trunk heating is described using a system of non-stationary heat conduction equations with a source part responsible for the heat release according to the Joule-Lenz law in the core of the tree trunk. The finite difference method is used to solve the differential heat equation. Finite-difference analogues are solved by the double-sweep method. Program realization is implemented in the built-in high-level language. The probability theory (conditional probability) is used to develop a probabilistic criterion for forest fire danger estimation. Results. A software tool is developed to estimate the tree ignition delay time as a result of the impact of a cloud-to-ground lightning discharge. The GIS-system component is developed in the high-level programming language Python. We have obtained probability distribution of forest fire occurrences from thunderstorms for the territory of the Timiryazevsky forestry in the Tomsk region is obtained. Conclusions. We have proposed a physically proved method for forecasting, monitoring and assessing forest fire danger caused by thunderstorm activity. The deterministic mathematical model is used to simulate tree ignition by the cloud-to-ground lightning discharge in conjunction with the probabilistic criterion for assessing forest fire danger. We have analysed forest fire danger for a typical territory of the Tomsk region (Timiryazevskiy forestry).