Multi-scale analyses of wildland fire combustion processes: Small-scale field experiments – atmospheric pressure

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)" small-scale field experiments were designed to investigate how contrasting fuel conditions (e.g., fuel load, particle type, bulk density), fire spread type (e.g., heading vs. backing), and ambient and fire-induced conditions (e.g., seasonality, moisture, flow, temperature) influenced physical processes associated with combustion (e.g., heat transfer, flame propagation, flow) and the scale-dependent coupling of these processes. Additionally, these experiments provide 1) a linkage between small-scale laboratory combustion experiments and large-scale operational prescribed fires, and 2) archived datasets for further model development and evaluation. Our experimental design incorporates complementary approaches, methods, and instrumentation employed at these other scales, to quantify critical properties of the experimental fires’ physics domains (e.g., fuels and ambient conditions) and processes associated with combustion (e.g., heat transfer, flame propagation, flow). The small-scale field experiments include a series of highly instrumented, intermediate-scale experiments conducted on 100 square meter plots at the Silas Little Experimental Forest, New Lisbon, New Jersey. This dataset contains data collected from nineteen burns in 2018. Eight pressure sensors (Bosch BMP 180/ BMP 280) were mounted within the burn block in two different configurations. For burns 1-19 and excluding burns 7-8, pressure sensors (PS) were mounted on the two center trusses at 2.5 to 3.0 meters (m), directly below a sonic anemometer. For burns 7 and 8, PS were mounted at 1.5 m and 3.5 m, above and below the 8 centermost sonics, respectively. These eight pressure sensors were logged at 10 hertz (Hz) on a single CR6 datalogger (Campbell Scientific). In addition, a single pressure sensor (Bosch BMP 180) was added to a control tower, starting with burn 4. The control pressure sensor was mounted at 2.5 m, directly below a sonic anemometer, and were logged at 10 Hz on a single CR1000 datalogger (Campbell Scientific). The control tower was located approximately 50 m south of burn area. The pressure sensor data were used to examine fine-temporal resolution variation in atmospheric pressure associated with the passage of fire fronts. Data include temperature (degrees Celsius (°C)) and air pressure (millibars (mbar)).
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 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/Program-Areas/Resource-Conservation-and-Resiliency/Air-Quality/Fire-Emissions/RC-2641. Please reference the plot layout and documentation data publication (Gallagher et al. 2022) as these data provide the sensor locations of each burn, a detailed description of data collected and a burn summary.