Evaluation of OMI operational standard NO2 column retrievals using in situ and surface-based NO2 observations
Evaluation of OMI operational standard NO2 column retrievals using in situ and surface-based NO2 observations
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DOI：
10.5194/acp-14-11587-2014
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发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Knepp, T. N.
中科院分区：
文献类型：
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作者：
Lamsal, L. N.;Krotkov, N. A.;Knepp, T. N.
我们结合飞机和表面原位测量以及多个地点的地面柱测量和美国大陆上空自下而上的氮氧化物排放清单，评估了从 NASA Aura 卫星上的臭氧监测仪器 (OMI) 检索到的标准操作二氧化氮 (NO2) 数据产品（OMNO2，版本 2.1）。尽管存在相当大的采样差异，OMI 的 NO2 垂直柱密度与飞机对流层 NO2 的原位测量、MAX-DOAS 和 Pandora 仪器对 NO2 柱的地面观测、光解转换器仪器的原位表面 NO2 测量以及自下而上的 NOx 排放清单具有适度的相关性 (r = 0.3-0.8)。总体而言，OMI 检索结果在城市地区往往较低，在偏远地区较高，但通常与其他测量结果一致在 +/- 20% 以内。没有明显一致的季节性偏差。不同数据集之间的对比结果揭示了 NO2 验证背后的复杂性。由于验证数据集稀缺且空间和时间有限，全球产品的验证范围仍然受到时空覆盖范围和检索条件的限制。 OMI 检索中使用的全球建模倡议 (GMI) 化学传输模型 (CTM) 的月平均垂直 NO2 剖面形状与现场飞机测量高度一致，但这些测量的剖面表现出相当大的日常变化，对每日检索的 NO2 柱影响高达 40%。对 OMI 对流层 NO2 柱的评估，以及 OMI 检索的 NO2 柱和模型模拟的 NO2 柱的比较，可以提供模型的诊断评估。
We assess the standard operational nitrogen dioxide (NO2) data product (OMNO2, version 2.1) retrieved from the Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite using a combination of aircraft and surface in situ measurements as well as ground-based column measurements at several locations and a bottom-up NOx emission inventory over the continental US. Despite considerable sampling differences, NO2 vertical column densities from OMI are modestly correlated (r = 0.3-0.8) with in situ measurements of tropospheric NO2 from aircraft, ground-based observations of NO2 columns from MAX-DOAS and Pandora instruments, in situ surface NO2 measurements from photolytic converter instruments, and a bottom-up NOx emission inventory. Overall, OMI retrievals tend to be lower in urban regions and higher in remote areas, but generally agree with other measurements to within +/- 20%. No consistent seasonal bias is evident. Contrasting results between different data sets reveal complexities behind NO2 validation. Since validation data sets are scarce and are limited in space and time, validation of the global product is still limited in scope by spatial and temporal coverage and retrieval conditions. Monthly mean vertical NO2 profile shapes from the Global Modeling Initiative (GMI) chemistry-transport model (CTM) used in the OMI retrievals are highly consistent with in situ aircraft measurements, but these measured profiles exhibit considerable day-to-day variation, affecting the retrieved daily NO2 columns by up to 40 %. This assessment of OMI tropospheric NO2 columns, together with the comparison of OMI-retrieved and model-simulated NO2 columns, could offer diagnostic evaluation of the model.