Multi-scale analyses of wildland fire combustion processes: Large-scale field experiments – three-dimensional wind and temperature

The United States Department of Defense (DoD) Strategic Environmental Research and Development Program (SERDP) funded project: Multi-scale Analyses of Wildland Fire Combustion Processes in Open-canopied Forests using Coupled and Iteratively Informed Laboratory-, Field-, and Model-based Approaches (RC-2641) conducted a large-scale (management-scale) field experiment during an operational prescribed burn to quantify how atmospheric dynamics across a wide range of spatial and temporal scales affect fire propagation, energy exchange, and fuel consumption. This experiment also provided an opportunity to fully examine how combustion related processes transfer across scales of particles and simple fuel beds in the laboratory, wind tunnel, small-scale, and operational prescribed burns as instrumentation used in small-scale field experiments was embedded in this experiment. In addition, the large-scale experiment also provides data necessary for simulation and model testing of coupled atmosphere-fire behavior prediction systems (e.g., WRF-SFire, WFDS, QUIC-Fire, FIRETEC) and coupled atmosphere-canopy-smoke dispersion prediction systems (e.g., ARPS-Canopy/FLEXPART). The large-scale field experiment includes data from a heavily instrumented ~12.1 hectare (ha) management-scale fire conducted at the Silas Little Experimental Forest in the Pinelands National Reserve (PNR) on March 13, 2019. This data publication contains data collected from 22 sonic anemometers (81000v, R.M. Young Inc.). Fifteen sonic anemometers were mounted on 5 meteorological towers within the burn area and a 3 sonics were mounted on the control tower approximately 225 meters (m) outside the burn permitter to the north. Three sonics anemometers were mounted on each tower at approximately 3, 10 and 19 m above the ground. Four additional sonics where installed around the west tower at approximately 3 m to compare with the 10 x 10-meter burns (small-scale field experiments). Sonic anemometers were logged at 10 hertz (Hz) using CR3000 dataloggers (Campbell Scientific). The Sonic data were used to explore fine-scale patterns of vertical turbulence above flame fronts. Pre-fire data were used to quantify ambient wind conditions before and after fire front passage, turbulence, sensible (convective) heat fluxes, and momentum fluxes above flame fronts during fires. Data include sampled horizontal and vertical wind speed (meters per second [m/s]) and temperature (degrees Celsius [°C]).Many DoD facilities utilize low intensity prescribed fire to manage hazardous fuels, restore ecological function and historic fire regimes, and encourage the recovery of threatened and endangered species in the forests they manage. Current predictive models used to simulate fire behavior during low-intensity prescribed fires (and wildfires) are empirically based, simplistic, and fail to adequately predict fire outcomes because they do not account for variability in fuel characteristics and interactions with important meteorological variables. This study used a suite of measurements at the fuel particle, fuel bed, field plot, and stand scales to quantify how variability in fuel characteristics and key meteorological factors interact to drive fire behavior during low intensity prescribed burns. These experiments were designed to inform the development and evaluation of mechanistic, physics-based models that explicitly account for combustion, turbulent transfer, and energy exchange by coupling and scaling individual component processes. These datasets provide measurements to improve the understanding of, and ability to accurately predict, fire behavior under a wide range of management scenarios.A summary of the SERDP Project RC-2641 can be found at the RC-2641 Project Overview (serdp-estcp.org): https://www.serdp-estcp.org/projects/details/a4a4642d-f2be-4e52-b678-454fe06afbc2/rc-2641-project-overview. Please reference the burn layout and documentation data publication (Gallagher et al. 2023, https://doi.org/10.2737/RDS-2022-0089) as these data provide the sensor locations of each burn, a detailed description of data collected and a summary of the conditions during the burn periods.

美国国防部（United States Department of Defense, DoD）战略环境研究与发展计划（Strategic Environmental Research and Development Program, SERDP）资助的项目：冠层开阔林分野火燃烧过程多尺度分析：采用耦合迭代的实验室、现场与模型方法（RC-2641），依托一次作业性计划性受控火烧开展了大规模（经营尺度）野外试验，旨在量化多时空尺度大气动力学过程如何影响火势蔓延、能量交换与可燃物消耗。由于小型野外试验所用的仪器嵌入本次试验中，该试验还为全面探究燃烧相关过程在实验室、风洞、小型样地以及作业性计划性火烧的颗粒尺度与简单可燃物床层间的跨尺度传递规律提供了契机。
此外，该大型野外试验还为耦合大气-火行为预测系统（如WRF-SFire、WFDS、QUIC-Fire、FIRETEC）以及耦合大气-冠层-烟雾扩散预测系统（如ARPS-Canopy/FLEXPART）的模拟与模型验证提供了必要的数据支撑。
该大型野外试验于2019年3月13日在松树带国家保护区（Pinelands National Reserve, PNR）内的赛拉斯·利特尔试验林开展，涉及一处经过密集仪器布设的约12.1公顷（ha）经营尺度火烧样地。本次数据发布包含从22台超声风速仪（sonic anemometer，81000v，R.M. Young公司）采集得到的数据：其中15台超声风速仪安装在火烧区域内的5座气象塔上，另有3台安装在火烧边界北侧约225米（m）外的对照塔上。每座塔上分别在距地面约3米、10米和19米高度处布设3台超声风速仪。此外，还在西侧塔周边约3米高度处额外布设了4台超声风速仪，用于与10×10米火烧样地（小型野外试验）的观测结果进行对比。超声风速仪通过CR3000数据采集器（Campbell Scientific公司）以10赫兹（Hz）的频率进行数据记录。
超声风速数据被用于探究火焰锋面上方的垂直湍流精细格局。火烧前的观测数据被用于量化火烧锋面过境前后的环境风况、湍流特征，以及火烧过程中火焰锋面上方的显热（对流）热通量与动量通量。本次数据集包含采样得到的水平与垂直风速（单位：米每秒[m/s]）以及气温（单位：摄氏度[°C]）。
美国国防部的诸多设施会利用低强度计划性火烧来管控危险可燃物、恢复生态功能与历史火制度（fire regime），并促进其所经营森林中受威胁与濒危物种的恢复。当前用于模拟低强度计划性火烧（以及野火）火行为的预测模型均基于经验，结构简化，且无法充分预测火行为结果，因为它们未考虑可燃物特征的变异性以及与关键气象变量的相互作用。本研究通过在可燃物颗粒、可燃物床层、样地以及林分尺度开展一系列观测，量化可燃物特征变异性与关键气象因子的相互作用如何驱动低强度计划性火烧过程中的火行为。本试验的设计初衷是，通过耦合并缩放各独立组分过程，为构建并评估显式考虑燃烧、湍流输送与能量交换的机理型物理模型提供支撑。本数据集可为提升对多种经营场景下火行为的认知与精准预测能力提供观测依据。
有关SERDP项目RC-2641的详细摘要可参见RC-2641项目概述页面（serdp-estcp.org）：https://www.serdp-estcp.org/projects/details/a4a4642d-f2be-4e52-b678-454fe06afbc2/rc-2641-project-overview。请务必引用火烧布局与相关文档的数据出版物（Gallagher等人，2023，https://doi.org/10.2737/RDS-2022-0089），该文献提供了各火烧样地的传感器布设位置、采集数据的详细说明以及火烧期间的环境条件总结。