基于参数空间分布的海洋生态系统模拟

Marine Ecosystem Modelling Based on Spatial Parameterizations

在模拟大尺度海洋生态系统时,由于子区域的生态系统有着各自的特征,导致参数值在空间上存在差异,因此参数在整个研究区域取常数的做法必须改进。基于此,使用气候模式FOAM的气侯态背景场驱动一个简单的三维海洋生态系统模型,并引入参数的空间分布,在全球尺度上通过伴随方法同化SeaWiFS叶绿素资料。引入参数空间分布后,同化结果得到很大改进:浮游植物表层生物量(氮)的平均差从0.1553减小至0.0606mmol·m-3,下降了60.9%,有效地降低了模拟值与观测值在空间上的差异;浮游植物表层生物量平均值也从0.1031上升至0.1252mmol·m-3,更接近SeaWiFS观测。实验结果表明通过引入参数的空间分布来改进海洋生态系统的模拟是可行的。

In modelling a large scale ecosystem, parameterization for one region should differ from that for another because the regional ecosystem might have the features of itself. Therefore it should be improved that the same set of parameters are used to model a large scale of system. For the improvement purpose, a simple 3D marine ecosystem model with the regional parameterizations is forced by the climate background field output from the FOAM climate model, and the adjoint assimilation technique is applied to the global chlorophll data of the sea WIFS. After the regional parameterizations have been used, the assimilation results become much better. The average error for the surface phytoplankton （N） is reduced from 0. 155 3 to 0. 060 6 mmol·m^-3, with a reducing rate of 60.9%. Therefore, the difference between the model results and the observations becomes effectively decreased. Also the mean value for surface phytoplankton rises from 0. 103 1 to 0. 125 2 mmol·m^-3, being closer to the SeaWiFS value from the observations. It is shown from the results that the regional parameterizations for the marine ecosystem modelling improve ment is feasible.