大气混合比率的氢氧自由基相对较短的寿命(微秒的顺序)。建模时空气质量或天气,时间步通常远远大于羟基的半衰期。这是如何计算数值稳定?是数值稳定的问题简单地忽略了?
2答案
氢氧自由基化学不是空气质量模型中显式地建模,所以数值的稳定性不是问题。相反,哦在pseudo-steady-state举行。例如,看到CMAQ的文档州:
CMAQ的气相,哦是假定为pseudo-steady状态,它不是一个运输的物种。这是因为氢氧自由基反应往往是催化(例如,消费和生产)。在水相化学,哦,是被云吸收水和在一个开放的云模型(即。,the design approach currently employed), absorbed species (e.g., OH) would be replenished via gas-to-cloud partitioning. However, due to operator splitting, aqueous and gas-phase chemistry are not solved simultaneously. To account for this and other uncertainties in predicted OH aqueous phase concentrations (e.g., neglect of production reactions (H2O2 + hv -> 2 OH) not currently implemented in aqchem), a steady-state assumption for OH is adopted in the aqueous chemistry routine.
通常,如果你想模型类似的氢氧自由基,可以使用盒模型如麦加,而不是化学传输模式。