Title | ||
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Investigation of Simultaneous Effects of Aerosol Properties and Aerosol Peak Height on the Air Mass Factors for Space-Borne NO2 Retrievals. |
Abstract | ||
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We investigate the simultaneous effects of aerosol peak height (APH), aerosol properties, measurement geometry, and other factors on the air mass factor for NO2 retrieval at sites with high NO2 concentration. A comparison of the effects of high and low surface reflectance reveals that NO2 air mass factor (AMF) values over a snowy surface (surface reflectance 0.8) are generally higher than those over a deciduous forest surface (surface reflectance 0.05). Under high aerosol optical depth (AOD) conditions, the aerosol shielding effect over a high-albedo surface is revealed to reduce the path-length of light at the surface, whereas high single scattering albedo (SSA) conditions (e.g., SSA = 0.95) lead to an increase in the aerosol albedo effect, which results in an increased AMF over areas with low surface reflectance. We also conducted an in-depth study of the APH effect on AMF. For an AOD of 0.1 and half width (HW) of 5 km, NO2 AMF decreases by 29% from 1.36 to 0.96 as APH changes from 0 to 2 km. In the case of high-AOD conditions (0.9) and HW of 5 km, the NO2 AMF decreases by 240% from 1.85 to 0.54 as APH changes from 0 to 2 km. The AMF variation due to error in the model input parameters (e.g., AOD, SSA, aerosol shape, and APH) is also examined. When APH is 0 km with an AOD of 0.4, SSA of 0.88, and surface reflectance of 0.05, a 30% error in AOD induces an AMF error of between 4.85% and -3.67%, an SSA error of 0.04 leads to NO2 VCD errors of between 4.46% and -4.77%, and a 30% error in AOD induces an AMF error of between -9.53% and 8.35% with an APH of 3 km. In addition to AOD and SSA, APH is an important factor in calculating AMF, due to the 2 km error in APH under high-SZA conditions, which leads to an NO2 VCD error of over 60%. Aerosol shape is also found to have a measureable effect on AMF under high-AOD and small relative azimuth angle (RAA) conditions. The diurnal effect of the NO2 profile is also examined and discussed. |
Year | DOI | Venue |
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2017 | 10.3390/rs9030208 | REMOTE SENSING |
Keywords | Field | DocType |
NO2,air mass factor,DOAS method,aerosol peak height | Optical depth,Air mass,Aerosol,Remote sensing,Albedo,Reflectivity,Geology,Single-scattering albedo | Journal |
Volume | Issue | ISSN |
9 | 3 | 2072-4292 |
Citations | PageRank | References |
4 | 1.02 | 0 |
Authors | ||
6 |
Name | Order | Citations | PageRank |
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Hyunkee Hong | 1 | 6 | 2.77 |
Hanlim Lee | 2 | 13 | 6.22 |
Jhoon Kim | 3 | 7 | 7.02 |
Ukkyo Jeong | 4 | 6 | 3.96 |
Jaeyong Ryu | 5 | 4 | 1.02 |
Dae Sung Lee | 6 | 43 | 9.73 |