Use of reanalysis meteorological data fields at regular grid nodes to fill gaps in forest fire hazard data

Under the conditions of escalating global warming, the risks associated with wildfires are significantly increasing. Consequently, the importance of wildfire analytics, particularly in forecasting fire hazard in forests, is growing. Solving these tasks is impossible without using historical data on weather conditions. However, traditional archives of actual meteorological data are not always consistent, often contain gaps, and in some cases, are inaccessible to researchers. In recent years, reanalysis methods have been actively developed, enabling the acquisition of homogeneous and well-structured data (at the nodes of a regular grid), typically calculated using hydrodynamic models with fixed configurations. Some measurements obtained through various international projects are publicly available on the Internet and can be used, for example, to fill in the gaps in existing archives. This is particularly important for improving regional fire hazard rating systems, which are essential for accurate and timely assessments of wildfire threats in natural environments. This study provides an analysis of the main informational products and their sources most suitable for the retrospective calculation of Russian fire hazard indices. Specifically, the ERA5 product variant «ERA5 hourly data on single levels from 1940 to present», developed by the European Centre for Medium-Range Weather Forecasts (ECMWF), allows analyses of such data over an 85-year period (since 1940).