During the 2019-20 summer season, Australia experienced frequent heatwave events with scorching temperatures and massive bushfires with dense smoke. These catastrophic heatwaves and bushfires resulted in huge socio-economic and ecological losses. The frequency and intensity of both heatwaves and bushfires are projected to increase in the future warming world. While considerable effort has been directed at understanding the physical mechanisms of these individual extreme events, an investigation of their interaction is lacking. We focus on the relationship between heatwaves and bushfire fuels by considering dead fine fuel moisture content, a critical factor that regulates the intensity, spread rate and the likelihood of profuse spotting of fires. We investigate the relationship by exploring the statistical correlations between various heatwave characteristics (frequency, duration, magnitude, and amplitude) and mean dead fine fuel moisture content over southeast Australia in the peak heat and fire season. This relationship varies among different heatwave characteristics as well as with regions. The prolonged duration of a heatwave is well associated with dead fine fuel dryness around the southeastern parts of the Southeast Australian region, whereas the hotter heatwave season favours the lower dead fine fuel moisture content over the Northeast parts of the Southeast Australia and central Victorian region. Results also suggest that dead fine fuel moisture content is significantly decreased on heatwave days compared to non-heatwave days. Lastly, we explored the effects of rainfall deficit on the relationship between heatwave and mean dead fine fuel moisture content by splitting the seasons based on the Standard Precipitation Index (SPI). Results show that the correlation strength is both seasonally and regionally dependent.

在2019-20夏季，澳大利亚经历了频繁的热浪事件，高温，浓密的大火和浓烟。这些灾难性的热浪和丛林大火造成了巨大的社会经济和生态损失。预计在未来的变暖世界中，热浪和丛林大火的频率和强度都会增加。尽管已经作出大量努力来理解这些个别极端事件的物理机制，但仍缺乏对其相互作用的研究。我们通过考虑燃料细末水分的含量，着重研究热浪和丛林火燃料之间的关系，这是调节强度，扩散率和大火点可能性的关键因素。我们通过探讨在热浪和火季高峰期间澳大利亚东南部各种热浪特征（频率，持续时间，幅度和振幅）与平均死细燃料水分含量之间的统计相关性来研究这种关系。这种关系在不同的热波特性之间以及随区域而变化。热浪的持续时间与东南澳大利亚地区东南部附近的细小燃料干死有关，而热浪旺季则有利于东南澳大利亚东北部地区和维多利亚州中部地区的细小燃料干湿物含量较低。结果还表明，与非热浪天相比，热浪天的死细燃料水分含量显着降低。最后，我们通过根据标准降水指数（SPI）划分季节，探索了降雨不足对热浪与平均死细燃料水分含量之间关系的影响。结果表明，相关强度既与季节相关，也与区域相关。