The Mellor-Yamada-Nakanishi-Niino (MYNN) parameterization applied in the Weather Research and Forecasting (WRF) model has been augmented to include the Eddy-Diffusion Mass-Flux (EDMF) approach to better represent transport by boundary-layer eddies. This change includes the addition of new parameters associated with convective updrafts and boundary-layer clouds that lead to new parametric sensitivities in the turbine-height wind speed compared to simulations using the standard MYNN parameterization. This work builds on efforts focused on WRF's MYNN parameterization by examining the sensitivity of wind speed to parameters in the MYNN-EDMF parameterization as a function of simulation duration. Summer and winter periods were selected from the second Wind Forecast Improvement Project (WFIP2). Five sets of simulations were completed for each season, with durations ranging from 2 to 6 days. The results show that the sensitivity to the new parameters associated with the EDMF scheme is generally small compared to other parameters in clear conditions, but the sensitivity to the entrainment becomes significant when the updraft fraction is large. The spread in the perturbed parameter ensembles was found to grow quickly over the first 8–19 h in the summer simulations and 17–24 h in the winter simulations with little change after that, regardless of the simulation length. A strong diurnal cycle in the parameter sensitivity was also found associated with the atmospheric stability, as well as an increase in the sensitivity to the entrainment parameter used in the EDMF parameterization that is associated with increasing fractional area covered by plumes.

中文翻译：

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MYNN-EDMF参数化中涡轮高度风参数灵敏度的时间演变和日变化

在天气研究和预测 (WRF) 模型中应用的 Mellor-Yamada-Nakanishi-Niino (MYNN) 参数化已得到增强，包括涡流扩散质量流 (EDMF) 方法，以更好地表示边界层涡流的传输。这一变化包括添加与对流上升气流和边界层云相关的新参数，与使用标准 MYNN 参数化的模拟相比，这些参数导致涡轮机高度风速的新参数敏感性。这项工作建立在 WRF 的 MYNN 参数化工作的基础上，通过检查风速对 MYNN-EDMF 参数化中参数的敏感性作为模拟持续时间的函数。夏季和冬季时段选自第二个风力预报改进项目 (WFIP2)。每个季节完成五组模拟，持续时间为 2 至 6 天。结果表明，与晴朗条件下的其他参数相比，与 EDMF 方案相关的新参数的敏感性通常较小，但当上升气流分数较大时，对夹带的敏感性变得显着。在夏季模拟中的前 8-19 小时和冬季模拟中的 17-24 小时内，扰动参数集合的分布迅速增长，之后几乎没有变化，无论模拟长度如何。还发现参数敏感性的强昼夜循环与大气稳定性有关，以及对 EDMF 参数化中使用的夹带参数的敏感性增加，这与羽流覆盖的分数面积增加有关。结果表明，与晴朗条件下的其他参数相比，与 EDMF 方案相关的新参数的敏感性通常较小，但当上升气流分数较大时，对夹带的敏感性变得显着。在夏季模拟中的前 8-19 小时和冬季模拟中的 17-24 小时内，扰动参数集合的分布迅速增长，之后几乎没有变化，无论模拟长度如何。还发现参数敏感性的强昼夜循环与大气稳定性有关，以及对 EDMF 参数化中使用的夹带参数的敏感性增加，这与羽流覆盖的分数面积增加有关。结果表明，与晴朗条件下的其他参数相比，与 EDMF 方案相关的新参数的敏感性通常较小，但当上升气流分数较大时，对夹带的敏感性变得显着。在夏季模拟中的前 8-19 小时和冬季模拟中的 17-24 小时内，扰动参数集合的分布迅速增长，之后几乎没有变化，无论模拟长度如何。还发现参数敏感性的强昼夜循环与大气稳定性有关，以及对 EDMF 参数化中使用的夹带参数的敏感性增加，这与羽流覆盖的分数面积增加有关。