Assessing the Ensemble Predictability of Precipitation Forecasts for the January 2015 and 2016 East Coast Winter Storms
Assessing the Ensemble Predictability of Precipitation Forecasts for the January 2015 and 2016 East Coast Winter Storms
复制标题
评估 2015 年 1 月和 2016 年东海岸冬季风暴降水预报的集合可预测性
DOI：
10.1175/waf-d-16-0153.1
复制
发表时间：
2017
影响因子：
2.9
通讯作者：
Richard H. Grumm
中科院分区：
文献类型：
--
作者：
S. Greybush;Seth Saslo;Richard H. Grumm
评估了2015年1月和2016年1月东海岸冬季风暴的集合预报能力，并用模式降水预报与观测数据集进行了验证。技能分数和可靠性图表表明，考虑到实际可预测性限度造成的实际预测误差，业务预报产生的大集合差异是有必要的。对于2015年的风暴，沿西缘急剧降水梯度的不确定性与沿海低压的位置误差有关，而沿海低压的位置误差可追溯到使用集合敏感性技术定位之前的500百帕波型。可预测水平图显示了事件的初始检测、信号出现和解决方案的收敛方面的预测提前期。对于2016年的风暴，全球集合至少提前6天发现了天气系统，而中尺度特征的可预测性仅限于几个小时。允许对流的WRF集合预报将降低尺度。
AbstractThe ensemble predictability of the January 2015 and 2016 East Coast winter storms is assessed, with model precipitation forecasts verified against observational datasets. Skill scores and reliability diagrams indicate that the large ensemble spread produced by operational forecasts was warranted given the actual forecast errors imposed by practical predictability limits. For the 2015 storm, uncertainties along the western edge’s sharp precipitation gradient are linked to position errors of the coastal low, which are traced to the positioning of the preceding 500-hPa wave pattern using the ensemble sensitivity technique. Predictability horizon diagrams indicate the forecast lead time in terms of initial detection, emergence of a signal, and convergence of solutions for an event. For the 2016 storm, the synoptic setup was detected at least 6 days in advance by global ensembles, whereas the predictability of mesoscale features is limited to hours. Convection-permitting WRF ensemble forecasts downscal...