An improved scheme for time-dependent boundary conditions in atmospheric general circulation models
An improved scheme for time-dependent boundary conditions in atmospheric general circulation models
复制标题
大气环流模型中时变边界条件的改进方案
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
F. Zwiers
中科院分区：
文献类型：
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作者：
J. Sheng;F. Zwiers
摘要大气环流模式（AGCMs）经常与边界条件或气候系统其他方面的时变观测相耦合。 一个典型的例子是大气模型相互比较项目（AMIP）实验协议，该协议要求根据观测到的月平均值确定海面温度和海冰范围。AGCM通常通过在每个时间步评估插值函数来合并规定的条件。典型的方案，例如加拿大气候模拟与分析中心（CCC）第二代GCM（GCM 2）中使用的方案，不保留月平均值，并且对插值时间序列具有平滑效应，这往往会降低年周期的幅度和海表温度（SST）的年际变化。通过求解一个大型线性方程组，可以得到一个简单的线性时间插值方案，该方案保留了观测到的月平均SST及其变率。新方案改进了以前在CCC GCM 2中使用的方案，消除了年际变率的大量损失（高达20%）和年周期的小衰减（平均小于4%）与旧方案。改进后的线性插值格式也易于适用于其他量。
Abstract Atmospheric general circulation models (AGCMs) are often “coupled” with time varying observations of boundary conditions or some other aspect of the climate system. A typical example is the Atmospheric Model Intercomparison Project (AMIP) experimental protocol, which required the specification of sea surface temperature and sea-ice extent from observed monthly means. AGCMs ordinarily incorporate the prescribed conditions by evaluating an interpolating function at each time step. Typical schemes, such as that used in the second generation GCM (GCM2) of the Canadian Centre for Climate Modelling and Analysis (CCC), do not preserve monthly means and have a smoothing effect on the interpolated time series which tends to reduce the amplitude of annual cycle and interannual variability of sea surface temperature (SST). By solving a large set of linear equations, a simple linear time-interpolation scheme that preserves the observed monthly mean SST and hence its variability can be obtained. The new scheme improves upon that used previously in CCC GCM2 by eliminating the substantial loss of interannual variability (up to 20%) and the small attenuation of the annual cycle (less than 4% on average) incurred with the old scheme. The improved linear interpolation scheme is easily adapted to other quantities.