Computational tools used to implement the critical-load approach of atmospheric deposition impact often do not elucidate modeling uncertainty making it difficult for environmental policy-makers to know how much confidence to put in its results, also hampering aspects that may need improving. This study evaluated acid deposition modeling for various parameterizations of the planetary boundary-layer (PBL) over the Terrace-Kitimat valley, a physiographically complex region of northwestern British Columbia. Of five schemes, simulations with the Mellor-Yamada-Nakanishi-Niino Level 3 and Mellor-Yamada-Janjic PBL schemes best captured weekly wet deposition fluxes of acidifying ions (SO₄²⁻, NO₃⁻, NH₄⁺) within a factor of 2 of observations at an industrial fence line station. Alongside the Yonsei University PBL scheme, these two schemes slightly overestimated the chemical species at a station that was distant from major anthropogenic precursor sources in the valley, hence useful for worst-scenario projections of atmospheric deposition on the natural environment. Forest soils in the vicinity of a large aluminum smelter in Kitimat was estimated to be in exceedance of critical load of acidity by 30.1–53.5 kg S ha⁻¹ yr⁻¹. Exceedance of critical load of nutrient nitrogen restricted to the Terrace area (≤7 km²), ranged between none and 0.71 kg ha⁻¹ yr⁻¹. This work provides guidance for using PBL schemes in the Weather Research and Forecasting model that is coupled to a deposition model when calculating critical-load exceedance over temperate, rugged, coastal geographies.

用于实现大气沉积影响的临界负荷方法的计算工具通常无法阐明模型的不确定性，这使环境政策制定者难以知道对其结果有多大的信心，也妨碍了可能需要改进的方面。这项研究针对不列颠哥伦比亚省西北部生理复杂地区的Terrace-Kitimat谷地行星边界层（PBL）的各种参数化评估了酸沉降模型。在五种方案中，用Mellor-Yamada-Nakanishi-Niino 3级和Mellor-Yamada-Janjic PBL方案进行的模拟可以最好地捕获每周酸化离子（SO ₄ ²⁻，NO ₃ ⁻，NH ₄ ⁺）在工业围栏线站观测值的2倍之内。除了延世大学的PBL计划外，这两个计划还高估了一个远离山谷中主要人为来源的前驱源的站点的化学物种，因​​此对于在自然环境下最坏的大气沉积预测很有用。据估计，基蒂马特一个大型铝冶炼厂附近的森林土壤比酸性临界负荷超出了30.1–53.5 kg S ha ^-1  yr ^-1。限制在梯田区域（≤7 km ²）的营养氮临界负荷超过，范围在无和0.71 kg ha ^-1  yr ^-1之间。这项工作为在天气研究和预报模型中使用PBL方案提供了指导，在计算温带，崎,、沿海地区的临界负荷超标时，该模型与沉积模型耦合。