Modeling Study of the Air Quality Impact of Record‐Breaking Southern California Wildfires in December 2017
Modeling Study of the Air Quality Impact of Record‐Breaking Southern California Wildfires in December 2017
复制标题
DOI：
10.1029/2019jd030472
复制
发表时间：
2019-06
期刊：
影响因子：
--
通讯作者：
Hongrong Shi;Zhe Jiang;Bin Zhao;Zhanqing Li;Yang Chen;Y. Gu;Jonathan H. Jiang;Meemong Lee
中科院分区：
文献类型：
--
作者：
Hongrong Shi;Zhe Jiang;Bin Zhao;Zhanqing Li;Yang Chen;Y. Gu;Jonathan H. Jiang;Meemong Lee
我们利用化学天气研究和预测模型，结合卫星和地面观测，调查了 2017 年 12 月 5 日至 18 日期间南加州破纪录的野火对空气质量的影响。这次野火事件是由干燥而强劲的圣安娜近海风驱动的，它在火灾形成和空气污染物输送中发挥了关键作用。通过利用高分辨率 (375 × 375 m2) 可见红外成像辐射计套件主动火灾探测得出的火灾排放物，模拟的细颗粒物 (PM2.5) 浓度的大小和时间演变与表面观测结果相当吻合（归一化平均偏差 = 4.0%）。同时，该模型通常可以从卫星观测中捕获气溶胶光学深度的空间模式。灵敏度测试表明，对火灾排放使用高空间分辨率并合理处理羽流上升（在表面注入的排放和上升到高层的排放之间公平分配）对于获得良好的 PM2.5 模拟结果非常重要。在圣安娜风最强期间，由于可能低估燃烧面积和风场变化的不确定性，PM2.5 模拟的偏差相对较大（约 50%）。 2017 年 12 月的火灾事件使顺风地区 14 天平均 PM2.5 浓度增加高达 231.2 微克/立方米，大大超过美国空气质量标准，可能对健康造成不利影响。在受火羽影响的地区，人类暴露于火灾引起的 PM2.5 的情况占全年 PM2.5 暴露总量的 14-42%。
We investigate the air quality impact of record‐breaking wildfires in Southern California during 5–18 December 2017 using the Weather Research and Forecasting model with Chemistry in combination with satellite and surface observations. This wildfire event was driven by dry and strong offshore Santa Ana winds, which played a critical role in fire formation and air pollutant transport. By utilizing fire emissions derived from the high‐resolution (375 × 375 m2) Visible Infrared Imaging Radiometer Suite active fire detections, the simulated magnitude and temporal evolution of fine particulate matter (PM2.5) concentrations agree reasonably well with surface observations (normalized mean bias = 4.0%). Meanwhile, the model could generally capture the spatial pattern of aerosol optical depth from satellite observations. Sensitivity tests reveal that using a high spatial resolution for fire emissions and a reasonable treatment of plume rise (a fair split between emissions injected at surface and those lifted to upper levels) is important for achieving decent PM2.5 simulation results. Biases in PM2.5 simulation are relatively large (about 50%) during the period with the strongest Santa Ana wind, due to a possible underestimation of burning area and uncertainty in wind field variation. The 2017 December fire event increases the 14‐day averaged PM2.5 concentrations by up to 231.2 μg/m3 over the downwind regions, which substantially exceeds the U.S. air quality standards, potentially leading to adverse health impacts. The human exposure to fire‐induced PM2.5 accounts for 14–42% of the annual total PM2.5 exposure in areas impacted by the fire plumes.