Evaluation and intercomparison of wildfire smoke forecasts from multiple modeling systems for the 2019 Williams Flats fire-猫眼课题宝

DOI：

10.5194/acp-21-14427-2021

发表时间：

2021-04

期刊：

Atmospheric Chemistry and Physics

影响因子：

6.3

通讯作者：

中科院分区：

地球科学1区

文献类型：

作者：

X. Ye;Pargoal Arab;R. Ahmadov;E. James;G. Grell;B. Pierce;Aditya Kumar;P. Makar;Jack Chen;D. Davignon;G. Carmichael;G. Ferrada;J. Mcqueen;Jianping Huang;Rajesh Kumar;L. Emmons;F. Herron-Thorpe;M. Parrington;R. Engelen;V. Peuch;Arlindo M. da Silva;A. Soja;E. Gargulinski;E. Wiggins;J. Hair;M. Fenn;T. Shingler;S. Kondragunta;A. Lyapustin;Yujie Wang;B. Holben;D. Giles;P. Saide

抽象。野火烟雾是人类和环境健康最重要的问题之一，与其对空气质量，天气和气候的重大影响有关。然而，生物质燃烧排放物和烟雾仍然是空气质量预测中最大的不确定性来源。在这项研究中，我们评估了美国华盛顿州威廉姆斯公寓火灾期间12个最先进的空气质量预报系统的烟雾排放和羽流预报，2019年8月，在火灾对区域到全球环境和空气质量的影响（FIREX-AQ）实地活动期间进行了集中观察。在同一框架下，基于多个平台的观测结果，对一天内的模型预报进行了相互比较，以揭示其在火灾排放、气溶胶光学厚度（AOD）、地面PM2.5、羽流注入和地面PM2.5与AOD之比方面的性能。烟雾有机碳（OC）排放量的比较表明，模型之间的每日总量范围很大，系数为20至50。有限的昼夜模式和每天的排放量的变化的代表性，突出了需要纳入新的方法来预测时间的演变和减少烟雾排放量估计的不确定性。烟雾AOD（sAOD）预测的评价表明，总体低估的幅度和烟羽面积几乎所有的模型，虽然高分辨率的模型有更好的代表性的细尺度结构的烟羽。基于FRP的火灾排放或同化卫星AOD数据驱动的模式通常优于其他模式。此外，由于低估了7日的排放量，2019年8月8日的sAOD主要在输送的烟羽上的大幅低估揭示了预测烟雾排放时使用的持久性假设的局限性。相比之下，地面烟雾PM2.5（sPM2.5）的预测显示出积极和消极的整体偏差，这些模型，与大多数成员提出更可观的sPM2.5的日变化。过度预测的sPM2.5被发现在夜间基于FRP的排放驱动的模型，这表明有必要提高垂直排放分配内和上方的行星边界层（PBL）。烟雾喷射高度进一步评估使用美国宇航局兰利研究中心的差分吸收高光谱分辨率激光雷达（DIAL-HSRL）在飞行观测期间收集的数据。随着火势在8月3日至8日变得更强，烟羽高度变得更深，每天的范围约为2-9公里。然而，发现所有模型的范围较窄，具有高估浅注入断面的羽流高度和低估显示较深注入的日子的倾向。被歪曲的羽流注入高度导致不准确的垂直羽流分配沿着对应于运输一天的老烟的横断面。表面PM2.5和气溶胶光学厚度的模型性能的离散性进一步建议通过评估它们的比率，这不能通过单独调整烟雾排放来补偿，但更归因于羽流注入的模型表示，除了其他可能的因素，包括PBL深度的演变和气溶胶光学性质假设。通过整合多个预报系统，这些结果为改善烟雾预报的途径提供了战略性见解。

Abstract. Wildfire smoke is one of the most significant concerns of human and environmental health, associated with its substantial impacts on air quality, weather, and climate. However, biomass burning emissions and smoke remain among the largest sources of uncertainties in air quality forecasts. In this study, we evaluate the smoke emissions and plume forecasts from twelve state-of-the-art air quality forecasting systems during the Williams Flats fire in Washington State, the U.S., August 2019, which was intensively observed during the Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field campaign. Model forecasts with lead times within one day are intercompared under the same framework based on observations from multiple platforms to reveal their performance regarding fire emissions, aerosol optical depth (AOD), surface PM2.5, plume injection, and surface PM2.5 to AOD ratio. The comparison of smoke organic carbon (OC) emissions suggests a large range of daily totals among the models with a factor of 20 to 50. Limited representations of the diurnal patterns and day-to-day variations of emissions highlight the need to incorporate new methodologies to predict the temporal evolution and reduce uncertainty of smoke emission estimates. The evaluation of smoke AOD (sAOD) forecasts suggests overall underpredictions in both the magnitude and smoke plume area for nearly all models, although the high-resolution models have a better representation of the fine-scale structures of smoke plumes. The models driven by FRP-based fire emissions or assimilating satellite AOD data generally outperform the others. Additionally, limitations of the persistence assumption used when predicting smoke emissions are revealed by substantial underpredictions of sAOD on 8 August 2019 mainly over the transported smoke plumes, owing to the underestimated emissions on the 7th. In contrast, the surface smoke PM2.5 (sPM2.5) forecasts show both positive and negative overall biases for these models, with most members presenting more considerable diurnal variations of sPM2.5. Overpredictions of sPM2.5 are found for the models driven by FRP-based emissions during nighttime, suggesting the necessity to improve vertical emission allocation within and above the planetary boundary layer (PBL). Smoke injection heights are further evaluated using the NASA Langley Research Center’s Differential Absorption High Spectral Resolution Lidar (DIAL-HSRL) data collected during the flight observations. As the fire became stronger over 3–8 August, the plume height became deeper with the day-to-day range of about 2–9 km a.g.l. However, narrower ranges are found for all models with a tendency of overpredicting the plume heights for the shallower injection transects and underpredicting for the days showing deeper injections. The misrepresented plume injection heights lead to inaccurate vertical plume allocations along the transects corresponding to transported one-day-old smoke. Discrepancies in model performance for surface PM2.5 and AOD are further suggested by the evaluation of their ratio, which cannot be compensated by solely adjusting the smoke emissions but are more attributable to model representations of plume injections, besides other possible factors including the evolution of PBL depths and aerosol optical property assumptions. By consolidating multiple forecast systems, these results provide strategic insight on pathways to improve smoke forecasts.

Evaluation and intercomparison of wildfire smoke forecasts from multiple modeling systems for the 2019 Williams Flats fire

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