A Maieutic Exploration of Nudging Strategies for Regional Climate Applications Using the WRF Model.
A Maieutic Exploration of Nudging Strategies for Regional Climate Applications Using the WRF Model.
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DOI：
10.1175/jamc-d-17-0360.1
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发表时间：
2018-08
影响因子：
3
通讯作者：
T. Spero;C. Nolte;Megan S. Mallard;J. Bowden
中科院分区：
文献类型：
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作者：
T. Spero;C. Nolte;Megan S. Mallard;J. Bowden
在天气研究和预报模式（WRF）中使用轻推来约束区域气候降尺度模拟越来越受欢迎，因为它可以减少误差并提高与驱动数据的一致性。虽然有些人注意到轻推是否有利于缩小规模，但很少有研究来确定最佳做法。事实上，许多已发表的论文使用默认的nudging配置（专为数值天气预报而设计），遵循同事使用的实践，或采用为其他区域气候模型开发的方法。在这里，一套45个为期三年的模拟WRF在美国大陆进行了系统和全面的研究各种轻推策略。这里的模拟使用了比以前发表的作品更长的测试期，以更好地评估每个策略在所有四个季节，多年和美国九个地区的稳健性。分析的重点是2米的温度和降水，这是两个最常见的需要缩小输出字段的空气质量，健康和生态系统的应用程序的评估。提出了几个具体的建议，以有效地使用轻推在WRF区域气候应用。特别地，谱轻推优于分析轻推。当它被用于行星边界层以上的风（通过平流层）和温度和湿度仅在自由对流层内时，光谱轻推在WRF中表现最好。此外，对水分的轻推对轻推系数非常敏感，WRF中默认的轻推系数太高而不能有效地用于水分。
The use of nudging in the Weather Research and Forecasting (WRF) Model to constrain regional climate downscaling simulations is gaining in popularity because it can reduce error and improve consistency with the driving data. While some attention has been paid to whether nudging is beneficial for downscaling, very little research has been performed to determine best practices. In fact, many published papers use the default nudging configuration (which was designed for numerical weather prediction), follow practices used by colleagues, or adapt methods developed for other regional climate models. Here, a suite of 45 three-year simulations is conducted with WRF over the continental United States to systematically and comprehensively examine a variety of nudging strategies. The simulations here use a longer test period than did previously published works to better evaluate the robustness of each strategy through all four seasons, through multiple years, and across nine regions of the United States. The analysis focuses on the evaluation of 2-m temperature and precipitation, which are two of the most commonly required downscaled output fields for air quality, health, and ecosystems applications. Several specific recommendations are provided to effectively use nudging in WRF for regional climate applications. In particular, spectral nudging is preferred over analysis nudging. Spectral nudging performs best in WRF when it is used toward wind above the planetary boundary layer (through the stratosphere) and temperature and moisture only within the free troposphere. Furthermore, the nudging toward moisture is very sensitive to the nudging coefficient, and the default nudging coefficient in WRF is too high to be used effectively for moisture.