Collaborative Research: Testing Hypotheses About Fire Using Data Syntheses and Fire Modeling

该研究项目将利用描述过去和现在火灾变化的数据集，调查环境和人类活动的变化如何随着时间的推移影响火灾。该项目还将开发一个全球火灾模型，以帮助测试关于环境因素和人类在控制区域到全球范围内火灾的位置、规模和频率方面所起作用的假设。该项目将提供有关火灾、气候和其他环境因素与人类活动之间关系的新信息和见解。该项目将有助于在地球系统过程知识方面取得更广泛的科学进展，该项目将提高目前正在将火纳入全球环境模拟的地球系统模型的质量。了解人类活动、气候和其他环境因素过去在区域和全球尺度上影响火灾的方式，对于理解未来火灾的行为方式至关重要。鉴于火灾对人类构成的威胁以及火灾在许多生态系统功能中发挥的关键作用，提高对火灾行为动态的认识具有相当大的实际效用。项目研究结果将有助于改进各种气候和土地利用条件下模型中控制火灾过程的表示，从而为有关自然资源和火灾管理工作的决策提供信息。该项目将为研究生提供教育和培训机会，并将协助编写有关火、自然系统和人类活动之间相互作用的课程材料，供中小学使用。该项目将使用基于卫星的火灾活动重建来验证现代模拟，并将推进数据收集，以研究过去影响火灾动态和影响的因素。调查人员将把过去一千年中仍在扩大的全球火灾数据库的信息与全球火灾建模的结果结合起来。过去的火灾活动将从给定深度的湖泊沉积物中的木炭颗粒以及通过使用放射性碳定年法确定木炭沉积的时间来估计。木炭记录将用于重建一系列气候和土地利用条件下过去的火灾活动水平，并将重建结果与过去全球火灾活动的各种模拟进行比较。将过去和现在的数据集与过去气候的模式模拟相结合，将为理解产生重建和观测到的火灾活动变化的具体过程提供比单独使用现代（卫星）数据集更严格的基础。

This research project will investigate how changes in environmental and human activities have influenced fires over time, using a combination of datasets that describe past and present variations in fire. The project also will develop a global fire model to help test hypotheses about the roles that environmental factors and humans have played in controlling the location, size, and frequency of fires at regional-to-global scales. The project will provide new information and insights about relationships among fire, climate and other environmental factors, and human activities. The project will contribute to broader scientific advances in knowledge regarding Earth system processes, and the project will enhance the quality of Earth system models that now are incorporating fire in simulations of the global environment. Knowledge of the ways that human activity, climate, and other environmental factors have affected fires in the past at both regional and global scales is critical to understanding how fires will behave in the future. Given the threats that fires pose for humans and the critical role that fires play in the functioning of many ecosystems, increased awareness of the dynamics of fire behavior has considerable practical utility. Project findings will facilitate enable improved representations of the processes that control fire in models across a variety of climate and land-use conditions, thereby informing decisions about natural resource and fire management efforts. The project will provide education and training opportunities for graduate students, and it will assist in the development of curricular materials dealing with the interactions among fire, natural systems, and human activities for use in elementary and secondary schools.This project will use satellite-based reconstructions of fire activity to validate modern-day simulations, and it will advance collection of data to study the factors that have influenced the dynamics and impact of fire in the past. The investigators will combine information from a still-expanding global database of fire over the last millennium with the outputs from global fire modeling. Past fire activity will be estimated from charcoal particles in lake sediments at a given depth as well as the time when the charcoal was deposited as determined through the use of radiocarbon dating. The charcoal records will be used to reconstruct past levels of fire activity under a range of climate and land-use conditions, and the reconstructions will be compared with various simulations of past global fire activity. Combining past and present datasets with model simulations of past climate will provide a more rigorous basis for understanding the specific processes that produce reconstructed and observed changes in fire activity than modern-day (satellite) datasets alone.