FORest Canopy Atmosphere Transfer (FORCAsT) 2.0: model updates and evaluation with observations at a mixed forest site
FORest Canopy Atmosphere Transfer (FORCAsT) 2.0: model updates and evaluation with observations at a mixed forest site
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DOI：
10.5194/gmd-2021-104
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发表时间：
2021-04
影响因子：
5.1
通讯作者：
D. Wei;H. D. Alwe;D. Millet;B. Bottorff;M. Lew;P. Stevens;J. Shutter;Joshua L. Cox;F. Keutsch;Q. Shi;S. Kavassalis;J. Murphy;K. Vasquez;H. Allen;E. Praske;J. Crounse;P. Wennberg;P. Shepson;A. Bui;H. Wallace;R. Griffin;N. May;M. Connor;J. Slade;K. Pratt;E. Wood;M. Rollings;B. Deming;Daniel C. Anderson;A. Steiner
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作者：
D. Wei;H. D. Alwe;D. Millet;B. Bottorff;M. Lew;P. Stevens;J. Shutter;Joshua L. Cox;F. Keutsch;Q. Shi;S. Kavassalis;J. Murphy;K. Vasquez;H. Allen;E. Praske;J. Crounse;P. Wennberg;P. Shepson;A. Bui;H. Wallace;R. Griffin;N. May;M. Connor;J. Slade;K. Pratt;E. Wood;M. Rollings;B. Deming;Daniel C. Anderson;A. Steiner
抽象的。上述预测（FORest Canopy Atmosphere Transfer）模式版本1.0通过实施五个主要变化更新为FORCAsT 2.0，包括（1）对操作者分裂的改变，将化学与排放和干沉积分离，这将气相化学的运行时间减少了70%，并产生了更真实的异戊二烯冠层剖面;（2）修改涡动扩散系数参数化，以在边界层中产生更大和更真实的垂直混合，这改善了在充分混合的条件下不切实际的模拟的一天结束时异戊二烯峰值，并提高了白天的气温;（3）更新可用测量的干沉积速度;（4）实施减少的加州理工学院异戊二烯机制（RCIM）以反映异戊二烯氧化的当前知识;和（5）扩展气溶胶模块以包括异戊二烯衍生气溶胶（iSOA）形成。沿着算子分裂、修正垂直混合和干沉降，RCIM改进了第一代异戊二烯氧化产物（甲基乙烯基酮和甲基丙烯醛）和一些第二代产物（如异戊二烯环氧二醇）的估算。在FORCAsT 2.0的气溶胶模块中包含异戊二烯导致7%的iSOA质量产率。最重要的iSOA前体是IEPOX和四官能化合物，它们共同占总iSOA的> 86%。在冠层中，由有机硝酸盐形成的iSOA更为重要，占总iSOA的11%.四官能组成高达23%的总iSOA的形成，突出的命运（即干沉积和气相化学）的后一代异戊二烯氧化产物在估计iSOA的形成的重要性。
Abstract. The FORCAsT (FORest Canopy Atmosphere Transfer) model version 1.0 is updated to FORCAsT 2.0 by implementing five major changes, including (1) a change to the operator splitting, separating chemistry from emission and dry deposition, which reduces the run time of the gas-phase chemistry by 70 % and produces a more realistic in-canopy profile for isoprene; (2) a modification of the eddy diffusivity parameterization to produce greater and more realistic vertical mixing in the boundary layer, which ameliorates the unrealistic simulated end-of-day peaks in isoprene under well-mixed conditions and improves daytime air temperature; (3) updates to dry deposition velocities with available measurements; (4) implementation of the Reduced Caltech isoprene mechanism (RCIM) to reflect the current knowledge of isoprene oxidation; and (5) extension of the aerosol module to include isoprene-derived aerosol (iSOA) formation. Along with the operator splitting, modified vertical mixing and dry deposition, RCIM improves the estimation of first generation isoprene oxidation products (methyl vinyl ketone and methacrolein) and some second generation products (such as isoprene epoxydiols). Inclusion of isoprene in the aerosol module in FORCAsT 2.0 leads to a 7 % mass yield of iSOA. The most important iSOA precursors are IEPOX and tetrafunctionals, which together account for > 86 % of total iSOA. The iSOA formed from organic nitrates are more important in the canopy, accounting for 11 % of the total iSOA. The tetrafunctionals compose up to 23 % of the total iSOA formation, highlighting the importance of the fate (i.e. dry deposition and gas-phase chemistry) of later-generation isoprene oxidation products in estimating iSOA formation.