The influence of data assimilation on the age of air calculated with a global chemistry‐transport model using ECMWF wind fields
The influence of data assimilation on the age of air calculated with a global chemistry‐transport model using ECMWF wind fields
复制标题
使用 ECMWF 风场通过全球化学输运模型计算数据同化对空气年龄的影响
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
P. van Velthoven
中科院分区：
文献类型：
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作者：
E. Meijer;B. Bregman;A. Segers;P. van Velthoven
空气年龄是一个代表运输过程的有用的综合量。大多数大气模型低估了空气的年龄，特别是在使用数据同化系统的风场时。尽管如此，数据同化对于提供真实的风是必要的。欧洲中期天气预报中心(ECMWF)对不同的预报时段使用不同的同化程序，预报使模式能够从同化程序的非物理调整中恢复过来。在这项研究中，我们通过对空气年龄的模拟来检验不同同化过程和预报周期对ECWMF风场的影响。对于所有数据集，空气的年龄都太年轻，对于45年的再分析数据(ERA-40)，它甚至异常年轻，这必须归因于ERA-40使用的数据同化程序。延长预测期在一定程度上解决了空气老化的问题，但不能令人满意。
The age of air is a useful integrated quantity that represents transport processes. Most atmospheric models underestimate the age of air, especially when wind fields from data assimilation systems are used. Nonetheless data assimilation is necessary to provide realistic winds. The European Centre for Medium‐Range Weather Forecasts (ECMWF) uses different assimilation procedures with various forecast periods, where forecasting allows the model to recover from the non‐physical adjustments of the assimilation procedure. In this study we examine the impact of different assimilation procedures and forecast periods on ECWMF wind fields by performing simulations of the age of air. For all data sets the age of air is too young, and for the 45‐years re‐analysis data (ERA‐40) it is even anomalously young, which has to be attributed to the data assimilation procedure used in ERA‐40. Extending the forecast period partially remedies the low ages of air, but to an unsatisfactory degree.