Abstract

This work is part of a study on the impact of black carbon (BC) transfer from various sources to the Arctic on climate change in the region. The main objectives are to develop software for analyzing the Lagrangian transport of air particles; assessing the deposition of aerosol particles by precipitation and the concentration of particles in the atmosphere; and obtaining, for specific conditions of atmospheric circulation during severe fires in the years of maximum reduction in the Arctic sea ice area, estimates of the relative residence time of air particles emitted by these fires over the Arctic Basin (AB), as well as the proportion of BC deposited in the AB from fires. This software package contains a module for calculating Lagrangian trajectories from a 4-dimensional wind array (u, v, ω, t), which contains horizontal wind components and an analog of vertical speed available from reanalysis, as well as modules for the postprocessing of the found trajectories, which allow us to obtain in a given area the residence time estimates, 3-dimensional BC concentration, and BC deposition on the surface, also using reanalysis data and some empirical constants. Since the main decrease in the Arctic sea ice area occurred in 2 years, 2007 and 2012, it was supposed to analyze the fires of these years; however, in 2007, there were no great fires, and in 2012 one fire was much larger than the others (K-217, March–June). This fire was chosen for the experiments: several sets of trajectories were obtained for it, corresponding to various options for choosing the initial conditions, and estimates were obtained for the fraction of trajectories that passed over the Arctic basin, the time spent there, and the fraction of BC deposited in the AB. Together, these estimates led to the conclusion that Siberian fires can hardly be the leading cause of the accelerated melting of Arctic sea ice.

中文翻译：

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西伯利亚严重森林火灾至北极盆地的黑碳远距离大气迁移

摘要

这项工作是关于黑碳（BC）从各种来源转移到北极对该地区气候变化影响的研究的一部分。主要目标是开发用于分析空气粒子拉格朗日传输的软件；通过降水评估气溶胶颗粒的沉积情况以及大气中颗粒的浓度；并针对北极海冰面积最大减少年份中严重火灾期间大气环流的具体条件，获得这些火灾排放的空气颗粒在北极盆地（AB）上空的相对停留时间的估计值，以及由于火灾而沉积在 AB 中的 BC 的比例。该软件包包含一个用于根据 4 维风阵列（u、v、 ω 、t）计算拉格朗日轨迹的模块，其中包含水平风分量和可从再分析中获得的垂直速度模拟，以及用于后处理的模块发现的轨迹，使我们能够获得给定区域的停留时间估计、3 维 BC 浓度和表面的 BC 沉积，同时还使用再分析数据和一些经验常数。由于北极海冰面积的减少主要发生在2007年和2012年这两年，因此应该对这几年的火灾进行分析；然而，2007 年没有发生大火，2012 年的一场火灾比其他火灾大得多（K-217，3 月至 6 月）。选择这场火灾进行实验：获得了几组轨迹，对应于选择初始条件的各种选项，并获得了经过北极盆地的轨迹部分、在那里花费的时间以及BC 的一部分存入 AB 中。总之，这些估计得出的结论是，西伯利亚大火很难成为北极海冰加速融化的主要原因。