Development and optimization of a wildfire plume rise model based on remote sensing data inputs – Part 2
Development and optimization of a wildfire plume rise model based on remote sensing data inputs – Part 2
复制标题
基于遥感数据输入的野火羽流上升模型的开发和优化 - 第 2 部分
DOI：
10.5194/acpd-15-9815-2015
复制
发表时间：
2015
影响因子：
6.3
通讯作者：
J. Kaiser
中科院分区：
文献类型：
--
作者：
R. Paugam;M. Wooster;J. Atherton;S. Freitas;M. Schultz;J. Kaiser
抽象的。生物质燃烧是相对较少的自然过程之一，它可以在远高于行星边界层的高度向大气中排放全球大量的气体和气溶胶，在某些情况下，高度超过10公里。因此，生物质燃烧排放的“喷射高度”是在考虑景观尺度火灾产生的烟羽的特征时，特别是在试图模拟其大气传输时需要了解的一个重要参数。在这里，我们进一步扩展了一个流行的一维烟羽上升模型中使用的公式，该模型广泛用于估计景观尺度的火烟羽流喷射高度，并开发和优化了这两个模型，以便它可以运行在更多的遥感观测集上。该模型非常适合应用于旨在了解烟羽下游影响的大气化学传输模型(CTMS)中，虽然有许多野火排放清单可用于此类CTMS，但很少有包括羽流喷射高度的信息。由于CTM分辨率通常在空间上太粗糙，无法捕捉到由景观尺度火灾释放的热量引起的垂直输送，因此估计排放喷射高度的方法通常基于参数化。我们对现有的一维羽流上升模型的扩展考虑了大气稳定性和潜热对羽流上升气流的影响，利用从MODIS卫星对地观测(EO)数据中提取的关于活跃火区和火辐射功率(FRP)的新信息以及ECMWF的大气廓线信息来驱动它。我们通过添加质量守恒方程和新的卷吸方案对模型进行了扩展，并根据与使用MISR EO传感器进行的烟羽高度反演得到的喷射高度的比较，优化了新添加的参数的值。我们的参数优化程序基于双重方法，依次使用模拟退火法和马尔可夫链蒙特卡罗不确定性测试，并试图确保适当收敛到合适的参数值，我们使用的训练数据集仅包含满足多个特定质量标准的火灾，包括从ECMWF和MISR数据得出的本地环境风切变极限，以及在连续MODIS观测之间仅显示相对较小变化的“稳定”羽流和火灾。使用我们的优化烟羽上升模式(PRMv2)，利用2003年在北美上空探测到的所有MODIS探测到的活跃火灾的信息，输出网格到0.1°水平和500米垂直分辨率网格，我们能够推导出野火喷射高度分布，其最大值扩展到实际基于观测的野火羽流数据集中所看到的比通过原始烟羽模型或这里测试的任何其他参数所得到的更高的海拔类型。我们还发现，我们的模型是唯一一个测试过的模型，它更准确地模拟了2003年8月17日加拿大艾伯塔省一场大火造成的非常高的羽流(6至8公里)，尽管即使我们的方法也没有像真正的羽流预期的那样到达平流层。我们的结果使我们相信，我们用来模拟野火羽流喷射高度的PRMv2方法是纳入CTMS以代表这一过程的有力候选者，但我们注意到，向模型提供数据所需数据的时空分辨率的重大进步也很可能带来我们更准确地表示此类现象的能力的关键改进，并且由于羽流高度观测的相对稀疏性以及它们目前相当有限的时间覆盖范围，不一定能很好地匹配火灾最活跃的时候(例如MISR仅限于上午的观测)，因此在详细验证此类模拟方面仍然存在挑战。
Abstract. Biomass burning is one of a relatively few natural processes that can inject globally significant quantities of gases and aerosols into the atmosphere at altitudes well above the planetary boundary layer, in some cases at heights in excess of 10 km. The "injection height" of biomass burning emissions is therefore an important parameter to understand when considering the characteristics of the smoke plumes emanating from landscape scale fires, and in particular when attempting to model their atmospheric transport. Here we further extend the formulations used within a popular 1D plume rise model, widely used for the estimation of landscape scale fire smoke plume injection height, and develop and optimise the model both so that it can run with an increased set of remotely sensed observations. The model is well suited for application in atmospheric Chemistry Transport Models (CTMs) aimed at understanding smoke plume downstream impacts, and whilst a number of wildfire emission inventories are available for use in such CTMs, few include information on plume injection height. Since CTM resolutions are typically too spatially coarse to capture the vertical transport induced by the heat released from landscape scale fires, approaches to estimate the emissions injection height are typically based on parametrizations. Our extensions of the existing 1D plume rise model takes into account the impact of atmospheric stability and latent heat on the plume up-draft, driving it with new information on active fire area and fire radiative power (FRP) retrieved from MODIS satellite Earth Observation (EO) data, alongside ECMWF atmospheric profile information. We extend the model by adding an equation for mass conservation and a new entrainment scheme, and optimise the values of the newly added parameters based on comparison to injection heights derived from smoke plume height retrievals made using the MISR EO sensor. Our parameter optimisation procedure is based on a twofold approach using sequentially a Simulating Annealing algorithm and a Markov chain Monte Carlo uncertainty test, and to try to ensure the appropriate convergence on suitable parameter values we use a training dataset consisting of only fires where a number of specific quality criteria are met, including local ambient wind shear limits derived from the ECMWF and MISR data, and "steady state" plumes and fires showing only relatively small changes between consecutive MODIS observations. Using our optimised plume rise model (PRMv2) with information from all MODIS-detected active fires detected in 2003 over North America, with outputs gridded to a 0.1° horizontal and 500 m vertical resolution mesh, we are able to derive wildfire injection height distributions whose maxima extend to the type of higher altitudes seen in actual observation-based wildfire plume datasets than are those derived either via the original plume model or any other parametrization tested herein. We also find our model to be the only one tested that more correctly simulates the very high plume (6 to 8 km a.s.l.), created by a large fire in Alberta (Canada) on the 17 August 2003, though even our approach does not reach the stratosphere as the real plume is expected to have done. Our results lead us to believe that our PRMv2 approach to modelling the injection height of wildfire plumes is a strong candidate for inclusion into CTMs aiming to represent this process, but we note that significant advances in the spatio-temporal resolutions of the data required to feed the model will also very likely bring key improvements in our ability to more accurately represent such phenomena, and that there remain challenges to the detailed validation of such simulations due to the relative sparseness of plume height observations and their currently rather limited temporal coverage which are not necessarily well matched to when fires are most active (MISR being confined to morning observations for example).
植被火灾火焰发射率中波红外和长波红外灰体假设的实验验证
影响因子：
3.1
作者：
Johnston J
通讯作者：
Johnston J