Experimental Tropical Cyclone Forecasts Using a Variable-Resolution Global Model
Experimental Tropical Cyclone Forecasts Using a Variable-Resolution Global Model
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DOI：
10.1175/mwr-d-15-0159.1
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发表时间：
2015-10-01
影响因子：
3.2
通讯作者：
Jablonowski, Christiane
中科院分区：
文献类型：
--
作者：
Zarzycki, Colin M.;Jablonowski, Christiane
在三角洲x; 14公里水平分辨率（0.1258）的热带气旋（TC）预报是使用社区大气模式（CAM）中的可变分辨率（V-R）网格完成的。2012年和2013年8月1日至10月31日，每天两次对预报进行整合，高分辨率的嵌套中心位于北大西洋和东太平洋盆地。使用CAM版本5（CAM 5）的物理参数化包，区域细化显着提高TC路径预报技巧相对于未细化网格（Dx; 55公里，0.58）。对于典型的TC预报积分周期（约1周），V-R预报能够几乎完全相同地再现全球统一的高分辨率预报的流场。模拟的强度一般太强，不能预报72小时以上。这种强度偏差是强大的，无论预测是否被迫与观测或气候的海面温度，并没有显着减轻一套敏感性模拟，旨在调查模型的时间步长和CAM的深对流参数化的影响。替换组件的默认物理与云层统一的Binormals（CLUBB）在较长的前置时间预测强度产生统计上显着的改善，虽然预测TC存在显着的结构差异。CAM预测飓风桑迪转向进入美国东北部的时间比使用相同初始条件的全球预报系统（GFS）模型早60小时，表明TC预测对模型配置的敏感性。与全球统一的高分辨率模拟相比，与V-R模拟相关的计算成本显著降低，表明变分辨率技术是未来数值天气预报应用的有前途的工具。
Tropical cyclone ( TC) forecasts at Delta x; 14- km horizontal resolution ( 0.1258) are completed using variableresolution ( V- R) grids within the Community Atmosphere Model ( CAM). Forecasts are integrated twice daily from 1 August to 31 October for both 2012 and 2013, with a high- resolution nest centered over the North Atlantic and eastern Pacific Ocean basins. Using the CAM version 5 ( CAM5) physical parameterization package, regional refinement is shown to significantly increase TC track forecast skill relative to unrefined grids ( Dx; 55 km, 0.58). For typical TC forecast integration periods ( approximately 1 week), V- R forecasts are able to nearly identically reproduce the flow field of a globally uniform high- resolution forecast. Simulated intensity is generally too strong for forecasts beyond 72 h. This intensity bias is robust regardless of whether the forecast is forced with observed or climatological sea surface temperatures and is not significantly mitigated in a suite of sensitivity simulations aimed at investigating the impact of model time step and CAM's deep convection parameterization. Replacing components of the default physics with Cloud Layers Unified by Binormals ( CLUBB) produces a statistically significant improvement in forecast intensity at longer lead times, although significant structural differences in forecasted TCs exist. CAM forecasts the recurvature of Hurricane Sandy into the northeastern United States 60 h earlier than the Global Forecast System ( GFS) model using identical initial conditions, demonstrating the sensitivity of TC forecasts to model configuration. Computational costs associated with V- R simulations are dramatically decreased relative to globally uniform high- resolution simulations, demonstrating that variable- resolution techniques are a promising tool for future numerical weather prediction applications.