A quasi chemistry-transport model mode for EMAC
A quasi chemistry-transport model mode for EMAC
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DOI：
10.5194/gmd-4-195-2011
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发表时间：
2011-01-01
影响因子：
5.1
通讯作者：
Hoor, P.
中科院分区：
文献类型：
--
作者：
Deckert, R.;Joeckel, P.;Hoor, P.
针对ECHAM/MESY大气化学数值模拟系统，提出了一种准化学输送模式(QCTM)。它允许通过抑制化学和动力学之间的任何反馈来量化化学信号。否则噪音会干扰得太厉害。该信号由两个QCTM模拟、参考模拟和灵敏度模拟的差值计算而成。为了避免反馈，模拟采用了以下离线化学场：(A)辐射活性物质的离线混合比进入辐射方案，(B)离线硝酸混合比进入极地平流层云的再分配和沉积方案，(C)离线甲烷氧化是化学水汽倾向的唯一来源。任何一组离线字段都足以抑制反馈，尽管可能与模拟设置不一致。使用参考模拟的设置，可以从非QCTM模拟产生足够的离线气候集合。测试模拟揭示了与(A)相关联的足够的离线字段的特殊重要性。当使用适当的硝酸场时，(B)的不一致可以忽略不计。可以接受的小的不一致来自(C)，但如果有足够的化学水蒸气倾向的处方，这些不一致应该会消失。QCTM和非QCTM之间的切换是通过名称列表开关完成的，不需要重新编译源代码。
A quasi chemistry-transport model mode (QCTM) is presented for the numerical chemistry-climate simulation system ECHAM/MESSy Atmospheric Chemistry (EMAC). It allows for a quantification of chemical signals through suppression of any feedback between chemistry and dynamics. Noise would otherwise interfere too strongly. The signal is calculated from the difference of two QCTM simulations, a reference simulation and a sensitivity simulation. In order to avoid the feedbacks, the simulations adopt the following offline chemical fields: (a) offline mixing ratios of radiatively active substances enter the radiation scheme, (b) offline mixing ratios of nitric acid enter the scheme for re-partitioning and sedimentation from polar stratospheric clouds, (c) and offline methane oxidation is the exclusive source of chemical water-vapor tendencies. Any set of offline fields suffices to suppress the feedbacks, though may be inconsistent with the simulation setup. An adequate set of offline climatologies can be produced from a non-QCTM simulation using the setup of the reference simulation. Test simulations reveal the particular importance of adequate offline fields associated with (a). Inconsistencies from (b) are negligible when using adequate fields of nitric acid. Acceptably small inconsistencies come from (c), but should vanish for an adequate prescription of chemical water vapor tendencies. Toggling between QCTM and non-QCTM is done via namelist switches and does not require a source code re-compilation.