基于时间滞后集合和实时偏差订正的气温精细化预报研究

Refined Air Temperature Forecast Based on Time-lagged Ensemble and Real-time Bias Correction

  • 摘要: 基于SWC-WINGS模式0.01° × 0.01°分辨率的小时2 m气温产品,利用时间滞后集合和实时偏差订正,得到新的逐小时滚动更新的1 km网格气温预报,并基于预报准确率、平均误差、平均绝对误差等指标,对2022年7—8月逐日逐时气温预报结果进行检验分析。结果表明:时间滞后集合预报准确率在各时效均高于SWC-WINGS模式最新时次预报,实时偏差订正可明显提升临近时效准确率,1~6 h时效的平均提高率为17.3%。SWC-WINGS模式对于四川地区高、低温预报存在明显的系统性偏差,时间滞后集合对于系统性偏差的改进能力有限,而实时偏差订正可将1 h时效上四川大部分地区低温和高温预报的平均绝对误差分别控制在1 ℃和2 ℃以内。针对2022年8月13日四川地区高温天气,时间滞后集合与实时偏差订正集成预报对SWC-WINGS模式预报有较好的订正效果。

     

    Abstract: Based on hourly 2m air temperature product of SWC-WINGS model with a resolution of 0.01° × 0.01°, a new 1km grid air temperature forecast with hourly rolling update was obtained by using time-lagged ensemble and real-time bias correction. The hourly air temperature forecast from July to August 2022 was verified by prediction accuracy, average error, and average absolute error. The results showed the accuracy of time-lagged ensemble forecast was higher than that of the up-to-date forecast, and the real-time bias correction leaded to obvious improvement with 17.3% in 1~6 h forecasts. The SWC-WINGS model had obvious systematic bias in the prediction of high and low temperature in Sichuan, and the time-lagged ensemble reduced the deviation weakly. The real-time bias correction could control the average absolute error of low and high temperature forecast in most areas of Sichuan within 1 ℃ and 2 ℃, respectively. For the high temperature weather in Sichuan on 13 August 2022, the integration forecast of time-lagged ensemble and real-time bias correction had a high positive skill compared with SWC-WINGS model.

     

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