Carbon emissions and radiative forcings from tundra wildfires in the Yukon–Kuskokwim River Delta, Alaska
Carbon emissions and radiative forcings from tundra wildfires in the Yukon–Kuskokwim River Delta, Alaska
复制标题
DOI：
10.5194/bg-20-1537-2023
复制
发表时间：
2023-04
期刊：
影响因子：
4.9
通讯作者：
Michael Moubarak;S. Sistla;S. Potter;S. Natali;B. Rogers
中科院分区：
文献类型：
--
作者：
Michael Moubarak;S. Sistla;S. Potter;S. Natali;B. Rogers
抽象的。苔原环境中野火的发生率正在上升，并且由于北极气候的快速变化，预计发生频率将继续增加。苔原野火会在全球范围内释放大量温室气体，影响地球的辐射平衡。在这里，我们开发了一种新方法来估算 2015 年阿拉斯加育空-库斯科奎姆三角洲 (YKD) 苔原野火中的碳损失以及由此产生的气体和气溶胶排放的辐射强迫。我们使用在火灾事件中幸存的两个植物参考点（Sphagnum fuscum 和 Dicranum spp）配对燃烧深度测量。 – 通过测量当地有机质和土壤碳特性来估计生态系统总有机质和碳损失。我们使用 Landsat 8 的火灾严重程度遥感数据来衡量整个受火灾影响区域的测量损失，预计 2015 年 YKD 野火中有机物总损失为 2.04 Tg，碳损失为 0.91 Tg，平均损失有机物为 3.76 kg m−2，碳损失为 1.68 kg m−2。为了证明这些火灾对地球辐射预算的影响，我们开发了一个简单但全面的框架来估计北极野火的辐射强迫。我们综合了关于 CO2、N2O、CH4、O3 及其前体以及火灾气溶胶的气态和气溶胶排放的寿命和辐射强迫的现有研究。该模型显示，火灾后 80 年，使用代表性浓度路径 (RCP) 4.5 的净正累积平均辐射强迫为 3.67 W m−2，使用 RCP 8.5 的净正累积平均辐射强迫为 3.37 W m−2，其中主要是二氧化碳排放。我们的研究结果强调了苔原野火对气候的影响，这些野火通过气体排放的辐射强迫，积极加剧了气候变暖并增加了火灾频率。
Abstract. Tundra environments are experiencing elevated levels of wildfire, and the frequency is expected to keep increasing due to rapid climate change in the Arctic. Tundra wildfires can release globally significant amounts of greenhouse gasses that influence the Earth's radiative balance. Here we develop a novel method for estimating carbon loss and the resulting radiative forcings of gaseous and aerosol emissions from the 2015 tundra wildfires in the Yukon–Kuskokwim Delta (YKD), Alaska. We paired burn depth measurements using two vegetative reference points that survived the fire event – Sphagnum fuscum and Dicranum spp. – with measurements of local organic matter and soil carbon properties to estimate total ecosystem organic matter and carbon loss. We used remotely sensed data on fire severity from Landsat 8 to scale our measured losses to the entire fire-affected area, with an estimated total loss of 2.04 Tg of organic matter and 0.91 Tg of carbon and an average loss of 3.76 kg m−2 of organic matter and 1.68 kg m−2 of carbon in the 2015 YKD wildfires. To demonstrate the impact of these fires on the Earth's radiation budget, we developed a simple but comprehensive framework to estimate the radiative forcing from Arctic wildfires. We synthesized existing research on the lifetime and radiative forcings of gaseous and aerosol emissions of CO2, N2O, CH4, O3 and its precursors, and fire aerosols. The model shows a net positive cumulative mean radiative forcing of 3.67 W m−2 using representative concentration pathway (RCP) 4.5 and 3.37 W m−2 using RCP 8.5 at 80 years post-fire, which was dominated by CO2 emissions. Our results highlight the climate impact of tundra wildfires, which positively reinforce climate warming and increased fire frequency through the radiative forcings of their gaseous emissions.