Climate change impacts on wildfire risk in seasonally dry forests

近年来，北美西部、澳大利亚和地中海季节性干旱森林的野火对生计、经济、生态系统甚至碳储存产生了创纪录的影响。雷击被认为是这些地区的主要火源，然而，到目前为止，对闪电的有限观测限制了对气候变化中闪电与野火之间关系的评估。因此，人们对气候变化对闪电引发野火的潜在影响知之甚少。在极端炎热和干燥的条件下，当植被处于最干燥和最易燃的时候，野火的点燃不成比例。由于气候变化，这种容易发生火灾的天气条件在全球变得越来越频繁。此外，全球变暖也可能促进陆地上闪电频率的增加。因此，气候变化通过增强森林可燃性和点火机会，呈现出野火发生的复合风险。该项目将通过观测揭示闪电点燃对季节性干旱森林现代野火模式的贡献，随后采用气候模型预测来评估未来气候变化对闪电点燃的影响。该项目将提高人们对未来全球森林野火风险可能如何变化的认识，以帮助社会做好准备和适应不断变化的风险，并优化气候智慧型和火灾智慧型再造林项目的规划。研究方法：在国际监督小组的支持下，学生将：通过结合卫星和地面传感器对闪电和火灾的观测，识别由闪电点燃的野火。评估雷击对野火时空格局的区域影响。检查决定闪电是否引发野火的气候阈值。根据气候模式预测，预测极端天气和闪电复合增加导致的未来野火风险变化。Python/R编程（高级）：数据分析，机器学习，地理空间分析。中国科学院气候模拟暑期学校（https://ncas.ac.uk/study-with-us/climate-modelling-summer-school/）。海外访问加州（2个月）和阿姆斯特丹（1个月）。参观英国气象局，与火和闪电建模者互动。支持参加国际会议并向学术期刊提交研究成果。

Scientific backgroundWildfires in the seasonally dry forests of western North America, Australia, and the Mediterranean have had record-breaking impacts on livelihoods, economies, ecosystems, and even carbon storage in recent years. Lightning strikes have been implicated as a major ignition source in these regions, however limited observations of lightning have until now restricted the assessment of relationships between lightning and wildfire in a changing climate. Consequently, the potential impact of climate change on wildfire ignitions by lightning are poorly understood.Wildfire ignitions occur disproportionately during extremely hot and dry conditions, when vegetation is at its driest and most flammable. Such fire-prone weather conditions are becoming more frequent globally due to climate change. Moreover, global warming might also promote increases in lightning frequency over land. Consequently, climate change presents compound risks of wildfire occurrence by enhancing both forest flammability and ignition opportunities.This project will use observations to unravel the contribution of lightning ignitions to modern wildfire patterns in seasonally dry forests, and subsequently employ climate model projections to evaluate the impact of future climate change on lightning ignitions. The project will improve understanding of how wildfire risks may change across the world's forests in future, with the view to help society prepare and adapt to changing risks and to optimise the planning of climate-smart and fire-smart re/afforestation programmes.Research MethodologyWith the support of an international supervisory team, the student will:identify lightning-ignited wildfires by combining observations of lightning and fire from satellites and ground-based sensors.evaluate the regional impact of lightning strikes on spatial and temporal patterns of wildfire. examine the climatic thresholds that determine whether lightning ignites wildfires.predict future changes in wildfire risk resulting from compound increases in extreme weather and lightning, based on climate model projections.TrainingProgramming with Python/R (advanced level): data analysis, machine learning, geospatial analysis. NCAS climate modelling summer school (https://ncas.ac.uk/study-with-us/climate-modelling-summer-school/).Overseas visits to co-supervisors in California (2 months) and Amsterdam (1 month).Visits to the UK Met Office to interact with fire and lightning modellers. Support to present at international conferences and submit findings to academic journals.