Papavasileiou Georgios, Giannaros Theodore M
Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Lofos Koufou, 15236 Penteli, Greece.
Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Lofos Koufou, 15236 Penteli, Greece.
Sci Total Environ. 2024 May 15;925:171715. doi: 10.1016/j.scitotenv.2024.171715. Epub 2024 Mar 17.
The identification of the large-scale atmospheric circulation patterns which are associated with extreme fire weather is of great importance for developing early warning systems, management strategies, and for increasing awareness and preparedness of all the involved entities, including both the public and practitioners. Such a forecasting approach is currently missing in Greece and many other countries. Furthermore, considering climate projections over the Mediterranean, which indicate an environment more conducive to wildfire activity, the need for timely forecasting of extreme fire weather becomes increasingly urgent. Here, we present an alternative fire weather forecasting framework using ERA5 reanalysis data of atmospheric variables and fire weather indices of the Canadian Forest Fire Weather Index System (CFFWIS) during the period June-October from 1979 to 2019. Within this framework, we define the critical fire weather patterns (CFWPs) of Greece associated with different levels of fire weather severity by applying Self-Organizing-Maps (SOMs) on mid-tropospheric geopotential height. We quantify the fire weather conditions associated with each CFWP. Using a set of CFFWIS indices and key fire weather variables, our SOM-based analysis reveals five distinct CFWPs linked to different levels and characteristics of fire weather severity. The lowest fire weather severity is associated with lower than average geopotential heights, and anomalous cold and moist weather. The highest fire weather severity is associated with higher than average geopotential heights, and anomalous hot, dry, and windy conditions, suggesting the potential for wind-driven wildfires. Our analysis yields elevated fire weather severity linked to a CFWP, when hot and dry conditions are accompanied by atmospheric instability, suggesting the potential for plume-driven wildfires and the potential for pyroconvection. The main advantage of this forecasting framework is that it could be used for providing valuable information regarding the upcoming fire weather conditions even up to 7-12 days in advance depending on the atmospheric predictability.
识别与极端火灾天气相关的大规模大气环流模式对于开发预警系统、管理策略以及提高包括公众和从业者在内的所有相关实体的认识和准备程度至关重要。目前希腊和许多其他国家缺少这样一种预测方法。此外，考虑到地中海地区的气候预测表明该环境更有利于野火活动，对极端火灾天气进行及时预测的需求变得越来越迫切。在此，我们提出一种替代性的火灾天气预测框架，该框架使用1979年至2019年6月至10月期间大气变量的ERA5再分析数据以及加拿大森林火灾天气指数系统（CFFWIS）的火灾天气指数。在这个框架内，我们通过对对流层中层位势高度应用自组织映射（SOM）来定义希腊与不同火灾天气严重程度水平相关的关键火灾天气模式（CFWP）。我们对与每个CFWP相关的火灾天气条件进行量化。使用一组CFFWIS指数和关键火灾天气变量，我们基于SOM的分析揭示了五个不同的CFWP，它们与火灾天气严重程度的不同水平和特征相关。最低的火灾天气严重程度与低于平均位势高度以及异常寒冷潮湿的天气有关。最高的火灾天气严重程度与高于平均位势高度以及异常炎热、干燥和有风的条件有关，这表明存在风驱动野火的可能性。我们的分析表明，当炎热干燥的条件伴有大气不稳定时，与CFWP相关的火灾天气严重程度会升高，这表明存在羽流驱动野火和热对流的可能性。这个预测框架的主要优点是，根据大气可预测性，它甚至可以提前7 - 12天用于提供有关即将到来的火灾天气状况的有价值信息。
