Wet removal of black carbon in Asian outflow: Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign
Wet removal of black carbon in Asian outflow: Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign
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DOI：
10.1029/2011jd016552
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发表时间：
2012-02-08
影响因子：
4.4
通讯作者：
Kim, Y. J.
中科院分区：
文献类型：
--
作者：
Oshima, N.;Kondo, Y.;Kim, Y. J.
2009年3月至4月，在东亚上空进行了东亚气溶胶辐射强迫（A-FORCE）飞机活动。在A-FORCE活动期间，在行星边界层（PBL）和自由对流层中获得了120个黑碳（BC）和一氧化碳（CO）的垂直廓线。本研究使用A-FORCE数据检验了BC在亚洲外流中的湿迁移。2009年3月30日黄海上空3-6 km高度采样的空气中BC和CO的浓度大大增强，这与北方中国上空的一个气旋导致的向上输送有关。2009年4月23日，东海上空5-6 km处的大气中CO浓度较高，但BC浓度没有明显增加，这是由于中国中部地区的积云对流伴随大量降水而导致的上升造成的。在整个A-FORCE期间，2 km以上采样的空气包裹中BC的传输效率（TEBC，即传输过程中未去除的BC颗粒比例）主要随着垂直传输过程中空气包裹经历的降水量的增加而下降，尽管它们的相关性不大（r（2）= 0.43）。TEBC还取决于从边界层输送的空气包裹的高度和它们在源区局部抬升的纬度。在A-FORCE期间，来自中国北方（北纬33度以北）并在2-4 km和4-9 km高度采样的空气包裹的TEBC中值分别为86%和49%。这些中位值系统地大于来自中国南方（北纬33度以南）的航空包裹的相应中位值（分别为69%和32%）。使用A-FORCE数据集将有助于减少全球和区域尺度模型中BC湿去除过程中的大的不确定性。
The Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign was conducted over East Asia in March-April 2009. During the A-FORCE campaign, 120 vertical profiles of black carbon (BC) and carbon monoxide (CO) were obtained in the planetary boundary layer (PBL) and the free troposphere. This study examines the wet removal of BC in Asian outflow using the A-FORCE data. The concentrations of BC and CO were greatly enhanced in air parcels sampled at 3-6 km in altitude over the Yellow Sea on 30 March 2009, associated with upward transport due to a cyclone with modest amounts of precipitation over northern China. In contrast, high CO concentrations without substantial enhancements of BC concentrations were observed in air parcels sampled at 5-6 km over the East China Sea on 23 April 2009, caused by uplifting due to cumulus convection with large amounts of precipitation over central China. The transport efficiency of BC (TEBC, namely the fraction of BC particles not removed during transport) in air parcels sampled above 2 km during the entire A-FORCE period decreased primarily with the increase in the precipitation amount that air parcels experienced during vertical transport, although their correlation was modest (r(2) = 0.43). TEBC also depended on the altitude to which air parcels were transported from the PBL and the latitude where they were uplifted locally over source regions. The median values of TEBC for air parcels originating from northern China (north of 33 degrees N) and sampled at 2-4 km and 4-9 km levels were 86% and 49%, respectively, during the A-FORCE period. These median values were systematically greater than the corresponding median values (69% and 32%, respectively) for air parcels originating from southern China (south of 33 degrees N). Use of the A-FORCE data set will contribute to the reduction of large uncertainties in wet removal process of BC in global- and regional-scale models.