Top-down isoprene emissions over tropical South America inferred from SCIAMACHY and OMI formaldehyde columns
Top-down isoprene emissions over tropical South America inferred from SCIAMACHY and OMI formaldehyde columns
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DOI：
10.1002/jgrd.50552
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发表时间：
2013-06-27
影响因子：
4.4
通讯作者：
Mao, Jingqiu
中科院分区：
文献类型：
--
作者：
Barkley, Michael P.;De Smedt, Isabelle;Mao, Jingqiu
我们使用甲醛（HCHO）垂直柱测量从扫描成像吸收光谱仪大气制图（科学仪器）和臭氧监测仪器（OMI），以及一个嵌套网格版本的全球测地系统化学迁移模型，以推断2006年期间热带南美洲自上而下的异戊二烯排放估计数，在HCHO空气质量因子（AMF）计算中使用不同的模型配置和假设。受生物质燃烧影响的场景被删除，每天使用火灾计数观测，我们使用本地模型的敏感性，以确定空间涂抹的影响很小的位置，虽然这包括在该地区的空间覆盖。我们发现使用HCHO柱数据更严格地限制了SCIAMACHY的总体异戊二烯排放范围从27- 61 TgC到31- 38 TgC，OMI的总体异戊二烯排放范围从45- 104 TgC到28- 38 TgC。自上而下的排放量的中位数不确定性约为60-260%的SCIAMACHY，和10-90%的OMI。我们发现，推断的排放量是最敏感的云分数和云顶压力（差异+/- 10%），先验异戊二烯排放量（+/- 20%），和甲醛垂直柱检索（+/- 30%）的不确定性。建造连续的自上而下的排放图，一般提高了全球测地系统化学模拟的甲醛柱在该地区，相对于SCIAMACHY和OMI数据。然而，如果当地时间自上而下的排放量按比例换算为月平均值，从SCIAMACHY推断的年排放量几乎是OMI的两倍。这种差异不能用传感器的不同采样或AMF计算中的不确定性来解释。
We use formaldehyde (HCHO) vertical column measurements from the Scanning Imaging Absorption spectrometer for Atmospheric Chartography (SCIAMACHY) and Ozone Monitoring Instrument (OMI), and a nested-grid version of the GEOS-Chem chemistry transport model, to infer an ensemble of top-down isoprene emission estimates from tropical South America during 2006, using different model configurations and assumptions in the HCHO air-mass factor (AMF) calculation. Scenes affected by biomass burning are removed on a daily basis using fire count observations, and we use the local model sensitivity to identify locations where the impact of spatial smearing is small, though this comprises spatial coverage over the region. We find that the use of the HCHO column data more tightly constrains the ensemble isoprene emission range from 27-61TgC to 31-38TgC for SCIAMACHY, and 45-104TgC to 28-38TgC for OMI. Median uncertainties of the top-down emissions are about 60-260% for SCIAMACHY, and 10-90% for OMI. We find that the inferred emissions are most sensitive to uncertainties in cloud fraction and cloud top pressure (differences of +/- 10%), the a priori isoprene emissions (+/- 20%), and the HCHO vertical column retrieval (+/- 30%). Construction of continuous top-down emission maps generally improves GEOS-Chem's simulation of HCHO columns over the region, with respect to both the SCIAMACHY and OMI data. However, if local time top-down emissions are scaled to monthly mean values, the annual emission inferred from SCIAMACHY are nearly twice those from OMI. This difference cannot be explained by the different sampling of the sensors or uncertainties in the AMF calculation.