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基于多模式降水预报产品对昆仑山北坡夏季暴雨预报性能检验对比

Comparison of forecast performance of summer rainstorms over the northern slopes of the Kunlun Mountains based on multi-model precipitation forecast products

  • 摘要: 昆仑山北坡夏季暴雨突发性强、预报预警难度大,模式降水预报产品对该区域暴雨的预报性能尚不明确。本文利用降水观测资料和多源融合降水产品,将传统点对点检验与MODE检验相结合,从降水强度和落区两个方面,对ECMWF、CMA-GFS和CMA-MESO三种模式的降水预报产品在2021—2022年夏季昆仑山北坡三次暴雨过程中的预报性能进行检验和对比,结果表明:(1) 三种模式普遍高估小雨和中雨,低估大雨和暴雨;其中,ECMWF对中雨和大雨的预报能力较强,CMA-MESO对暴雨预报能力更优,CMA-GFS对暴雨的预报能力低于其他两种模式。(2) 在暴雨过程的强(弱)降水时段,三种模式的漏(空)报率较高;三种模式对暴雨强度的低估,主要由对降水量的低估,和对降水频次的高估所致。(3) ECMWF模式在24 h和3 h累计降水目标与实况的匹配数量上优于CMA-GFS和CMA-MESO模式,ECMWF模式24 h累计降水目标较实况位置以偏南和偏东为主,CMA-GFS和CMA-MESO模式以偏南和偏西为主;三种模式对降水目标姿态的预报能力均较强,对降水目标面积的预报普遍偏小。

     

    Abstract: Summer rainstorms on the northern slope of the Kunlun Mountains is highly sudden. This makes forecasting and early warning very difficult. The performance of model precipitation forecast products in predicting rainstorm in this region remains unclear. Based on precipitation observation data and multi-source merged precipitation products, this study combines traditional point-to-point verification with the MODE method to evaluate and compare the forecast performance of ECMWF, CMA-GFS, and CMA-MESO models for three rainstorm events on the northern slope of the Kunlun Mountains during summer 2021-2022, assessing both precipitation intensity and spatial distribution.The results are as follows. (1) All three models tend to overestimate light and moderate rainfall but underestimate heavy rain and rainstorms. The ECMWF model performs better in capturing moderate and heavy rain, while CMA-MESO shows superior skill in rainstorm forecasting, outperforming CMA-GFS. (2) During intense and weak rainfall phases of rainstorm events, all three models show higher false alarm and miss rates; this underestimation of torrential rain intensity primarily arises from the systematic underestimation of precipitation amounts coupled with overestimation of precipitation frequency. (3) ECMWF outperforms CMA models in matching 24-hour and 3-hour accumulated precipitation objects with observations. ECMWF’s 24-hour precipitation objects show a southward and eastward displacement, while CMA models exhibit a southward and westward bias. All models effectively capture the morphology of precipitation objects but consistently underestimate their coverage area.

     

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