Evaluating the Experimental High-Resolution Rapid Refresh–Alaska Modeling System Using USArray Pressure Observations
Evaluating the Experimental High-Resolution Rapid Refresh–Alaska Modeling System Using USArray Pressure Observations
复制标题
使用 USArray 压力观测评估实验性高分辨率快速刷新 - 阿拉斯加建模系统
作者：
T. McCorkle;J. Horel;A. Jacques;T. Alcott
高分辨率快速刷新阿拉斯加（HRRR-AK）建模系统提供3公里的水平分辨率和0-36小时的天气预报指导阿拉斯加。这项研究评估了2016年12月至2017年6月期间可用的HRRR-AK系统的实验版本，然后在2018年7月由国家环境预测中心进行操作部署。地面压力观测从158个国家气象局（NWS）站同化在模式的生产周期和压力观测从101个USAray便携式阵列（TA）站没有同化被用来评估265个完整的0-36小时的高度计设置（地面压力降低到海平面）的预测。TA网络是阿拉斯加天气观测最近最大的扩展，并提供了一个独立的评估模型的性能在此期间。在整个研究期间，HRRR-AK 0-h预报之间的高度计设置的系统差异较大，相对于未同化的TA观测比相对于同化的NWS观测。在从随后的每个1-36小时高度计设置预报中消除这些初始偏差后，该模型在NWS和TA位置的36小时预报均方根误差具有可比性。该模型的治疗迅速变暖和下坡风，开发在阿拉斯加山脉的背风面在2月12日至15日进行检查。HRRR-AK 0-h预报用于诊断这一时期的天气和中尺度条件。随着下坡风事件的演变，模型预测低估了下坡风温度和强度的突然增加，误差较小。
The High-Resolution Rapid Refresh–Alaska (HRRR-AK) modeling system provides 3-km horizontal resolution and 0–36-h forecast guidance for weather conditions over Alaska. This study evaluated the experimental version of the HRRR-AK system available from December 2016 to June 2017, prior to its operational deployment by the National Centers for Environmental Prediction in July 2018. Surface pressure observations from 158 National Weather Service (NWS) stations assimilated during the model’s production cycle and pressure observations from 101 USArray Transportable Array (TA) stations that were not assimilated were used to evaluate 265 complete 0–36-h forecasts of the altimeter setting (surface pressure reduced to sea level). The TA network is the largest recent expansion of Alaskan weather observations and provides an independent evaluation of the model’s performance during this period. Throughout the study period, systematic differences in altimeter setting between the HRRR-AK 0-h forecasts were larger relative to the unassimilated TA observations than relative to the assimilated NWS observations. Upon removal of these initial biases from each of the subsequent 1–36-h altimeter setting forecasts, the model’s 36-h forecast root-mean-square errors at the NWS and TA locations were comparable. The model’s treatment of rapid warming and downslope winds that developed in the lee of the Alaska Range during 12–15 February is examined. The HRRR-AK 0-h forecasts were used to diagnose the synoptic and mesoscale conditions during this period. The model forecasts underestimated the abrupt increases in the temperature and intensity of the downslope winds with smaller errors as the downslope wind events evolved.