Performance and evaluation of the MRI Regional Climate Model with the spectral boundary coupling method
Performance and evaluation of the MRI Regional Climate Model with the spectral boundary coupling method
复制标题
谱边界耦合法MRI区域气候模型的性能与评估
DOI：
10.2151/jmsj1965.78.4_477
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发表时间：
2000
影响因子：
3.1
通讯作者：
H. Kida
中科院分区：
文献类型：
--
作者：
H. Sasaki;Y. Sato;Kazuyoshi Adachi;H. Kida
一个有限区域的模式必须在很长一段时间内集成，以模拟区域气候。本文将谱边界耦合（SBC）方法应用于区域气候模式，以调整外粗网格模式和内细网格模式之间扰动的相移，并抑制模式中不可避免地在侧边界附近产生的噪声。在这项研究中，MRI区域气候模式（MRI/RCM）的水平转换网格大小为40公里（在60°）嵌套在全球分析数据集（GANL），这是由日本气象厅数值预报部门（NPD/JMA）。在1994年1月和8月对模型进行了为期一个月的积分，采用了下列四种不同的边界条件：（i）常规的横向边界条件，即，不使用SBC方法的边界松弛方法（情况A），（ii）用于所有层的SBC方法，并且不使用边界松弛方法（情况B），（iii）仅在σ = 0.5水平以上使用SBC方法且不使用边界松弛方法（情况C），以及（iv）在所有层处使用边界松弛方法且仅在σ = 0.5水平以上使用SBC方法（情况D）。模拟结果与观测结果进行了比较，用一些统计方法进行了验证。统计分析结果表明，当不使用SBC方法时，850 hPa高度场在侧边界附近的均方根误差（RMSE）小于计算区域中心附近的均方根误差。与此相反，当使用SBC方法时，它在中心附近的RMSE小于侧边界附近的RMSE。在夏季个例中，SBC方法对850 hPa高度场有一定的改善作用。但是，对于所有层都使用SBC方法对地面气温和降水的得分并不好。通过使用SBC方法，几乎所有的分数仅在a = 0.5水平以上得到改善。在冬季的情况下，边界松弛方法有效地抑制了噪声，而SBC方法表现出一点改善。然而，最好的分数是从两种方法的组合中获得的。几乎所有的统计值表明，SBC方法仅适用于a = 0.5以上的区域气候模式在整个季节，特别是在夏季的情况下。
A limited area model has to be integrated over a long period to simulate a regional climate. The spectral boundary coupling (SBC) method is used for a regional climate model to adjust the phase shift of disturbances between the outer coarse mesh model and the inner fine mesh model, and to suppress the noise which is inevitably developing near the lateral boundary in our model. In this study, the MRI regional climate model (MRI/RCM) with a horizontal transformed grid size of 40 km (at 60°) is nested in the Global Analysis data set (GANL), which was produced by the Numerical Prediction Division of the Japan Meteorological Agency (NPD/JMA). One-month long integrations of the model are performed for January and August 1994 with the following four different boundary conditions; (i) the conventional lateral boundary condition, namely, the boundary relaxation method without using the SBC method (CASE A), (ii) the SBC method used for all layers and without the boundary relaxation method (CASE B), (iii) the SBC method used only above the σ = 0.5 level and without the boundary relaxation method (CASE C), and (iv) the boundary relaxation method at all layers and the SBC method used only above the σ = 0.5 level (CASE D). The simulated results are verified in comparison with observations using some statistical methods. The results of the statistical evaluation show that when the SBC method is not used, the Root Mean Square Error (RMSE) of the height at the 850 hPa level near the lateral boundary is smaller than that around the center of the calculation domain. In contrast, when the SBC method is used, the RMSE of it around the center is smaller than that near the lateral boundary. In the summer case, the height at the 850 hPa level is improved by using the SBC method. However, using the SBC method for all layers is not good for the scores of surface air temperature and precipitation. Almost all the scores are improved by using the SBC method only above the a = 0.5 level. In the winter case, the boundary relaxation method suppresses noise effectively, while the SBC method shows a little improvement. The best score, however, is obtained from the combination of both the methods. Almost all the statistical values show that the SBC method for only above the a = 0.5 is useful for the regional climate model throughout both the seasons, particularly in the summer case.