Contribution of biomass burning to black carbon deposition on Andean glaciers: consequences for radiative forcing
Contribution of biomass burning to black carbon deposition on Andean glaciers: consequences for radiative forcing
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DOI：
10.1088/1748-9326/acb371
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发表时间：
2023-01
影响因子：
6.7
通讯作者：
E. Bonilla;L. Mickley;E. Beaudon;L. Thompson;W. Rodriguez;Cruz Encarnación;C. Whicker;M. Flanner;G. Schmitt;P. Ginot
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作者：
E. Bonilla;L. Mickley;E. Beaudon;L. Thompson;W. Rodriguez;Cruz Encarnación;C. Whicker;M. Flanner;G. Schmitt;P. Ginot
自 20 世纪 60 年代以来，安第斯冰川迅速融化。虽然部分融化可能是由于温室气体增加导致的人为气候变化造成的，但黑碳 (BC) 等吸光颗粒的沉积也可能发挥了作用。我们假设亚马逊盆地和其他地方的火灾产生的黑碳可能沉积在安第斯冰川上，从而降低了地表反照率并导致进一步融化。在这里，我们通过将大气化学模型与秘鲁四个山区（奎尔卡亚、瓦斯卡兰、亚纳帕查和沙拉普）和玻利维亚一处地点（伊利马尼）雪或冰中的碳黑观测相结合，研究了碳黑沉积对安第斯山脉2014-2019年反照率变化的作用。我们发现，化学输运模型 GEOS-Chem 模拟的 2014-2019 年年平均冰 BC 浓度与最长记录地点 Huascarán 观测到的浓度大致一致，高估了 15%-40%。根据地点的不同，火灾产生的烟雾占总湿沉积通量和干沉积通量的 20%–70%。沉积的其余黑碳来自化石燃料燃烧。使用雪反照率模型，我们发现在晴空条件下，仅烟雾BC沉积在雪上的年平均辐射强迫范围为+0.1至+3.2 W m−2，相应的平均反照率降低为0.04%–1.1%。这些范围取决于地点和雪粒大小。这一结果意味着亚马逊生物质燃烧对安第斯山脉的辐射强迫可能产生重大的气候影响。
Andean glaciers have melted rapidly since the 1960s. While some melting is likely due to anthropogenic climate change driven by increasing greenhouse gases, deposition of light-absorbing particles such as black carbon (BC) may also play a role. We hypothesize that BC from fires in the Amazon Basin and elsewhere may be deposited on Andean glaciers, reducing the surface albedo and inducing further melting. Here we investigate the role of BC deposition on albedo changes in the Andes for 2014–2019 by combining atmospheric chemistry modeling with observations of BC in snow or ice at four mountain sites in Peru (Quelccaya, Huascarán, Yanapaccha, and Shallap) and at one site in Bolivia (Illimani). We find that annual mean ice BC concentrations simulated by the chemical transport model GEOS-Chem for 2014–2019 are roughly consistent with those observed at the site with the longest record, Huascarán, with overestimates of 15%–40%. Smoke from fires account for 20%–70% of total wet and dry deposition fluxes, depending on the site. The rest of BC deposited comes from fossil fuel combustion. Using a snow albedo model, we find that the annual mean radiative forcing from the deposition of smoke BC alone on snow ranges from +0.1 to +3.2 W m−2 under clear-sky conditions, with corresponding average albedo reductions of 0.04%–1.1%. These ranges are dependent on site and snow grain size. This result implies a potentially significant climate impact of biomass burning in the Amazon on radiative forcing in the Andes.