A 20-Year Climatology of a NICAM AMIP-Type Simulation
A 20-Year Climatology of a NICAM AMIP-Type Simulation
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DOI：
10.2151/jmsj.2015-024
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发表时间：
2015-01-01
影响因子：
3.1
通讯作者：
Sugi, Masato
中科院分区：
文献类型：
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作者：
Kodama, Chihiro;Yamada, Yohei;Sugi, Masato
首次使用14公里网格的非静水二十面体大气模型（NICAM）进行20年积分，以获得模拟大气的气候平均值和日年际变化。使用云微物理方案明确计算云，没有积云对流方案。模拟是在大气模型比对项目类型条件下进行的，不同之处在于使用板片海洋模型将海面温度推向观测到的历史值。分析结果的重点是热带扰动，包括热带气旋 (TC) 和马登-朱利安振荡 (MJO)。NICAM 模拟了大气气候平均状态和变化的许多方面。降水的地理分布，包括年际、季节和日变化，都得到了很好的再现。对纬向平均基本态、云和大气层顶部辐射进行了定性模拟，但存在一些严重偏差，例如低估的低云、短波反射、温暖的表面和热带对流层上层。TC和MJO是模拟的主要焦点。在模拟中，由于模拟热带气旋的真实强度，以最大风速的客观阈值来检测热带气旋。各洋盆TC生成的季节变化得到了很好的模拟。 MJO 和热带波的统计特性在时空功率谱中得到了很好的再现，与之前的 NICAM 研究一致。这意味着平流层的变化也被再现，正如本研究部分揭示的那样。亚洲季风分析表明，气候学上的北太平洋西部季风爆发发生在观测爆发点附近，并且在一定程度上再现了拜乌锋。一些显着的模型偏差仍然存在，这表明需要进一步改进模型。结果表明，高分辨率全球非静水力模型有可能揭示气候系统中的多尺度现象。
A 20-year integration by the nonhydrostatic icosahedral atmospheric model (NICAM) with a 14 km mesh was conducted for the first time to obtain a climatological mean and diurnal to interannual variability of a simulated atmosphere. Clouds were explicitly calculated using a cloud microphysics scheme without cumulus convection scheme. The simulation was performed under the atmospheric model intercomparison project-type conditions, except that sea surface temperature was nudged toward observed historical values using the slab ocean model. The results are analyzed with a focus on tropical disturbances, including tropical cyclones (TCs) and the Madden-Julian oscillation (MJO).NICAM simulates many aspects of atmospheric climatological mean state and variability. The geographical distributions of precipitation, including interannual, seasonal, and diurnal variations, are well reproduced. Zonal mean basic states, clouds, and top-of-atmosphere radiation are qualitatively simulated, though some severe biases such as underestimated low clouds, shortwave reflection, warmer surface, and tropical upper troposphere exist.TCs and MJO are the main focus of the simulation. In the simulation, TCs are detected with the objective thresholds of maximum wind speed due to the realistic intensity of simulated TCs. The seasonal march of TC genesis in each ocean basin is well simulated. The statistical property of the MJO and tropical waves is well reproduced in the space-time power spectra, consistent with previous NICAM studies. This implies that the stratospheric variability is also reproduced, as partially revealed in this study. Asian monsoon analysis shows that climatological western North Pacific monsoon onset occurs near the observed onset, and that the Baiu front is reproduced to some extent. Some significant model biases still exist, which indicates a need for further model improvements. The results indicate that a high-resolution global nonhydrostatic model has the potential to reveal multiscale phenomena in the climate system.