Implementation of HONO into the chemistry-climate model CHASER (V4.0): roles in tropospheric chemistry
Implementation of HONO into the chemistry-climate model CHASER (V4.0): roles in tropospheric chemistry
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DOI：
10.5194/gmd-2021-385
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发表时间：
2021-12
影响因子：
5.1
通讯作者：
Phuc Thi Minh Ha;Y. Kanaya;F. Taketani;M. D. Andrés Hernández;Ben Schreiner;K. Pfeilsticker;K. Sudo-K.-S
中科院分区：
文献类型：
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作者：
Phuc Thi Minh Ha;Y. Kanaya;F. Taketani;M. D. Andrés Hernández;Ben Schreiner;K. Pfeilsticker;K. Sudo-K.-S
抽象。亚硝酸（HONO）是一种重要的大气气体，它对NOx和HOx的循环有贡献，但它在全球大气光化学中的作用尚未完全了解。本研究首次在化学气候模式CHASER（MIROC-ESM）中实现了HONO形成的三条途径，以探索三种物理现象：气相动力学反应（GRs），直接排放（EM）和云/气溶胶粒子（HRs）的非均相反应。利用OMI的大气观测数据对模拟结果进行了评价（臭氧监测仪器），EANET（东亚酸沉降监测网）/ EMEP（欧洲监测和评价方案）地面静止观测，R/V米拉伊号观测，和飞机上的测量EMeRGe-Asia-2018（特大城市对区域到全球尺度污染物传输和转化的影响）。我们发现，在建模过程中包含HONO化学减少了模型对PM2.5，NO3−/HNO 3，NO2，OH，O3和CO测量的偏差，特别是在对流层下部和北太平洋（NP）地区。我们发现，反演的对流层HONO的全球丰度为1.4 TgN。在三种来源途径中，HRs和EM分别占HONO净产量的63%和26%.我们还观察到，气溶胶表面的反应贡献了更大的HONO（51%）比那些在云表面（12%）。与EMeRGe-Asia-2018的空中测量结果相比，该模型在亚洲近海地区的白天HONO显示出显着的负偏差，表明存在未知的白天HONO源。NO2近地面和对流层中层气溶胶吸收的加强、云吸收和直接HONO排放都是潜在的未知HONO来源。我们还发现，模拟的HONO丰度及其对NOx-O3化学的影响对NO2向HONO（相对于HNO 3）的非均相转化的产率敏感。包含HONO将全球对流层NOx（NO + NO2）水平降低20.4%，从而削弱对流层氧化能力，这反过来又增加了CH 4寿命（13%）和CO丰度（8%）。在以前的模拟研究中被忽略的云粒子表面的HRs是这些影响的主要驱动因素。在夏季期间，由于NOx水平显著降低（50- 95%），NP区域中OH（40- 67%）和O3（30- 45%）水平的显著降低，这种效果尤其显著。相比之下，中国（北京）气溶胶表面的HRs使OH和O3冬季平均水平分别提高了600- 1700%和10- 33%。总的来说，我们的研究结果表明，一个全球模型，不考虑HONO异质机制（特别是HRs云粒子表面）可能会错误地预测HONO在偏远地区和污染地区的影响。
Abstract. Nitrous acid (HONO) is an important atmospheric gas given its contribution to the cycles of NOx and HOx, but its role in global atmospheric photochemistry is not fully understood. This study, for the first time, implemented three pathways of HONO formation in the chemistry-climate model CHASER (MIROC-ESM) to explore three physical phenomena: gas-phase kinetic reactions (GRs), direct emission (EM), and heterogeneous reactions on cloud/aerosol particles (HRs). We evaluated the simulations by the atmospheric measurements from the OMI (Ozone Monitoring Instrument), EANET (Acid Deposition Monitoring Network in eastern Asia) / EMEP (European Monitoring and Evaluation Programme) ground-based stationary observations, observations from the ship R/V Mirai, and aircraft-based measurements by ATom1 (atmospheric tomography) and EMeRGe-Asia-2018 (Effect of Megacities on the Transport and Transformation of Pollutants on the Regional to Global scales). We showed that the inclusion of the HONO chemistry in the modeling process reduces the model bias against the measurements for PM2.5, NO3−/HNO3, NO2, OH, O3, and CO, especially in the lower troposphere and the North Pacific (NP) region. We found that the retrieved global abundance of tropospheric HONO was 1.4 TgN. Of the three source pathways, HRs and EM contributed 63 % and 26 % to the net HONO production, respectively. We also observed that, reactions on the aerosol surfaces contributed larger amounts of HONO (51 %) than those on the cloud surfaces (12 %). The model exhibited significant negative biases for daytime HONO in the Asian off-coast region, compared with the airborne measurements by EMeRGe-Asia-2018, indicating the existence of unknown daytime HONO sources. Strengthening of aerosol uptake of NO2 near-surface and in the middle troposphere, cloud uptake, and direct HONO emission are all potential yet-unknown HONO sources. We also found that the simulated HONO abundance and its impact on NOx-O3 chemistry are sensitive to the yield of the heterogeneous conversion of NO2 to HONO (vs. HNO3). Inclusion of HONO reduces global tropospheric NOx (NO + NO2) levels by 20.4 %, thereby weakening the tropospheric oxidizing capacity, which in turn, increases CH4 lifetime (13 %) and CO abundance (8 %). HRs on the surfaces of cloud particles, which have been neglected in previous modeling studies, are the main drivers of these impacts. This effect is particularly salient for the substantial reductions of levels of OH (40–67 %) and O3 (30–45 %) in the NP region during summer given the significant reduction of NOx level (50–95 %). In contrast, HRs on aerosol surfaces in China (Beijing) enhance OH and O3 winter mean levels by 600–1700 % and 10–33 %, respectively, with regards to their minima in winter. Overall, our findings suggest that a global model that does not consider HONO heterogeneous mechanisms (especially HRs on cloud particle surfaces) may erroneously predict the effect of HONO in remote areas and polluted regions.