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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >CONVECTIVE TRANSPORT OF BIOMASS BURNING EMISSIONS OVER BRAZIL DURING TRACE A
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CONVECTIVE TRANSPORT OF BIOMASS BURNING EMISSIONS OVER BRAZIL DURING TRACE A

机译：轨迹A期间巴西上空生物量燃烧排放的对流传输

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A series of large mesoscale convective systems that occurred during the Brazilian phase of GTE/TRACE A (Transport and Atmospheric Chemistry near the Equator-Atlantic) provided an opportunity to observe deep convective transport of trace gases from biomass burning. This paper reports a detailed analysis uf flight 6, on September 27, 1992, which sampled cloud- and biomass-burning-perturbed regions north of Brasilia. High-frequency sampling of cloud outflow at 9-12 km from the NASA DC-8 showed enhancement of CO mixing ratios typically a factor of 3 above background (200-300 parts per billion by volume (ppbv) versus 90 ppbv) and significant increases in NO, and hydrocarbons, Clear signals of lightning-generated NO were detected; we estimate that at least 40% of NOx at the 9.5-km level and 32% at 11.3 km originated from lightning, Four types of model studies have been performed to analyze the dynamical and photochemical characteristics of the series of convective events. (1) Regional simulations for the period have been performed with the NCAR/Penn State mesoscale model (MM5), including tracer transport of carbon monoxide, initialized with observations. Middle-upper tropospheric enhancements of a factor of 3 above background are reproduced. (2) A cloud-resolving model (the Goddard cumulus ensemble (GCE) model) has been run for one representative convective cell during the September 26-27 episode. (3) Photochemical calculations (the Goddard tropospheric chemical model), initialized with trace gas observations (e.g., CO, NOx, hydrocarbons, O-3) observed in cloud outflow, show appreciable O-3 formation postconvection, initially up to 7-8 ppbv O-3/d. (4) Forward trajectories from cloud outflow levels (postconvective conditions) put the ozone-producing air masses in eastern Brazil and the tropical Atlantic within 2-4 days and over the Atlantic, Africa, and the Indian Ocean in 6-8 days, Indeed, 3-4 days after the convective episode (September 30, 1992), upper tropospheric levels in the Natal ozone sounding show an average increase of similar to 30 ppbv (3 Dobson units (DU) integrated) compared to the September 28 sounding. Our simulated net O-3 production rates in cloud outflow are a factor of 3 or more greater than those in air undisturbed by the storms, Integrated over the 8- to 16-km cloud outflow layer, the postconvection net O-3 production (similar to 5-6 DU over 8 days) accounts for similar to 25% of the excess O-3 (15-25 DU) over the South Atlantic. Comparison of TRACE A Brazilian ozonesondes and the frequency of deep convection with climatology [Kirchhoff et al., this issue] suggests that the late September 1992 conditions represented an unusually active period for both convection and upper tropospheric ozone formation. [References: 17]
机译：在巴西GTE / TRACE A阶段（赤道-大西洋附近的运输和大气化学）期间发生的一系列大型中尺度对流系统，为观察生物质燃烧产生的痕量气体的深度对流运输提供了机会。本文报告了1992年9月27日进行的第6航班的详细分析，该采样对巴西利亚北部的云和生物量燃烧扰动区域进行了采样。距离NASA DC-8 9-12公里处的云流出的高频采样表明，CO混合比的提高通常比背景高3倍（200-300十亿分之体积（ppbv）对90 ppbv），并且显着增加在NO和碳氢化合物中，检测到闪电产生的NO的清晰信号;我们估计，在9.5公里的水平上至少有40％的NOx和在11.3公里的水平上有32％的NOx来自闪电。已经进行了四种类型的模型研究，以分析一系列对流事件的动力学和光化学特征。 （1）使用NCAR / Penn州中尺度模型（MM5）进行了该时期的区域模拟，包括一氧化碳的示踪物迁移，并通过观测进行了初始化。再现了对流层中上层比背景高3倍的增强。 （2）在9月26日至27日的情节期间，已经为一个代表性对流单元运行了一个云解析模型（戈达德积云集合（GCE）模型）。 （3）光化学计算（戈达德对流层化学模型），以云流出时观察到的微量气体观测值（例如，CO，NOx，碳氢化合物，O-3）初始化，显示出对流后可观的O-3形成，最初高达7-8 ppbv O-3 / d。 （4）来自云层流出水平（对流条件）的前向轨迹使巴西东部和热带大西洋中产生臭氧的空气团在2-4天之内，而大西洋，非洲和印度洋在6-8天之内，确实在对流事件发生后3-4天（1992年9月30日），纳塔尔臭氧测深的对流层高层显示出与9月28日测深相比平均增加了30 ppbv（3个Dobson单位（DU））。对流后的净O-3产量（在类似的情况下，在8至16公里的云流出层上综合计算），我们在云流出中模拟的O-3净净生产率比未受风暴干扰的空气高3倍或更多。到8天达到5-6 DU），相当于南大西洋上空O-3（15-25 DU）过量的25％。 TRACE A巴西臭氧探空仪和深对流频率与气候学的比较[Kirchhoff等，本期]表明，1992年9月下旬的条件代表了对流和对流层臭氧形成的异常活跃时期。 [参考：17]

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