Fire weather and lightning fires in a changing climate

野地大火在加拿大屡见不鲜，在过去十年中，每年平均有8000场大火烧毁200万公顷土地。这一地区的大部分烧毁是由林分更新的高强度树冠火灾造成的。这些高强度的火灾可能对社区产生重大影响；例如，2011年的奴隶湖火灾和2003年的基洛纳火灾造成了数亿美元的损失。 这项研究将侧重于考察火灾天气、燃料湿度、闪电、火灾发生预测和气候变化的三项相关研究。这些研究的目标是：1)开发一种使用气象站、雷达和闪电活动的混合方法，通过气象站观测、闪电活动水平和降水雷达数据的内插来估计整个地形的风暴总降雨量；2)开发和确定加拿大1-3天闪电预测模型的准确性；3)为加拿大开发1-3天闪电火灾预测系统，然后将该预测系统与未来气候的环流模型一起使用，以估计21世纪剩余时间的闪电和闪电引发的火灾。 火灾天气的最大挑战之一是确定气象站之间的天气条件，特别是降水的位置和数量。在火灾季节，许多降水本质上是对流的；阵雨和雷阵雨在空间和时间上都有很大的变化。加拿大火灾天气指数系统中的燃料湿度是通过观测温度、降水、风速和相对湿度来确定的。目前，我们只处理降水，因为它是计算整个地区的燃料水分和火灾危险时最大的不确定性来源。我们将根据天气观测、雷达和闪电活动改进降雨量估计。 闪电引起的火灾发生预测模型已经存在多年，大多数模型使用过去24小时内观测到的闪电活动和观测到的燃料湿度来估计火灾发生。未来一两天的预报是可能的，但这些预报是基于观测到的闪电和从天气预报得出的燃料湿度预测的暂缓火灾(在地下冒烟，但在天气条件有利之前不会发展为火焰燃烧)。这种目前的方法是有限的，因为它没有在火灾发生预测中考虑额外的闪电。将为加拿大开发一个三天闪电预报模式。 将为加拿大开发一个闪电引起的火灾发生预测系统。使用这个火灾发生预测系统和三天闪电预测模型以及大气环流模式数据，我们将模拟21世纪剩余时间内由闪电和雷电引起的火灾发生。 拟议的工作将导致火灾研究的进展，这将导致日常火灾管理活动发生有意义的变化，有助于保护加拿大人和我们的社区。

Wildland fire is a common occurrence in Canada with 8000 fires burning 2 million hectares on average every year during the past decade. Most of this area burned results from stand-renewing high-intensity crown fires. These high intensity fires can have significant impact on communities; for example, the fires in Slave Lake in 2011 and Kelowna in 2003 sustained damages measured in 100s of millions of dollars. This research will focus on three related studies examining fire weather, fuel moisture, lightning, fire occurrence prediction and climate change. The objectives of these studies are to: 1) develop a blended method using weather stations, radar and lightning activity to estimate total storm precipitation across the landscape through the interpolation of weather stations observations, the level of lightning activity ( as a proxy for precipitation) and precipitation radar data, 2) develop and determine the accuracy of a 1-3 day lightning forecast model for Canada, and 3) develop a 1-3 day lightning-caused fire occurrence prediction system for Canada and then use this prediction system along with General Circulations Models of future climate to estimate the lightning and the lightning – caused fire occurrence for the rest of the 21st century. One of the largest challenges with the fire weather is determining the weather conditions between weather stations and in particular the location and amount of precipitation. During the fire season much of the precipitation is convective in nature; showers and thundershowers that are highly variable in space and time. Fuel moisture in the Canadian Fire Weather Index System is determined by observations of temperature, precipitation, wind speed and relative humidity. At this time, we are addressing only precipitation because it is the source of the largest uncertainty when calculating fuel moisture and fire danger across the landscape. We will develop improved precipitation estimates from the weather observations, radar and lightning activity. Lightning-caused fire occurrence prediction models have been available for years and most models use observed lightning activity from the last 24 hours and observed fuel moisture to estimate fire starts. Forecasts for the next day or two are possible but these forecasts are for hold-over fires (fires that smoulder underground but don’t progress to flaming combustion until the weather conditions are conducive) based on the observed lightning and forecasted fuel moisture derived from weather forecasts. This current approach is limited as it does not consider additional lightning in the fire occurrence prediction. A three day lightning forecast model will be developed for Canada. A lightning-caused fire occurrence prediction system will be developed for Canada. Using this fire occurrence prediction system and the three day lightning forecast model along with General Circulation Model data we will model lightning and lighting-caused fire occurrence for the rest of the 21st century. The proposed work will lead to advances in fire research that will result in meaningful changes in day-to-day fire management activities that will help protect Canadians and our communities.