INTEGRATED FRACTIONS SKILL SCORE FOR THE ASSESSMENT OF PRECIPITATION

作者：张博,赵滨

摘要：Traditional skill scores(e.g., the threat score) used in the high-resolution verification of precipitation are affected by a 'double penalty' caused by slight spatial or temporal displacements, which can lead to misleading evaluations. The fractions skill score(FSS) is a popular spatial verificaiton measure that can be used to solve these problems. It can determine useful and skillful scores by neighborhood analysis, which can be used to monitor the performance of operational forecasts. However, the FSS provides different scores at each spatial scale and it is difficult to obtain a definite score for the assessment of precipitation to analyze the temporal variabilities of daily forecasts. We previously reported a modified FSS assessment method and showed that a particular analysis scale had a significant advantage in the verification of operational forecasts of precipitation. To compensate for the lack of artificial definition in the analysis scale, we report here a new integrated score that satisfies a Gaussian weight function to average the FSS over all scales. We describe the advantages of the new score in the verification of forecasts of daily and hourly precipitation, taking forecast products from the GRAPES regional model and quantitative precipitation estimation products from the National Meteorological Information Center during June and July 2017 and investigating the differences between these results and those obtained with the traditional category score. We found that a value of 0.5 can be used as a standard for the skillful FSS in the forecast of heavy rainfall. The integrated score can maintain all the advantages seen in previous studies in the verification of daily and hourly precipitation and show excellent application prospects. The long-term verification including different seasons also find that the score can effectively improve the identification characteristics of the assessment.

发文机构：National Meteorological Center China Meteorological Administration Numerical Weather Prediction Center

关键词：FRACTIONSSKILLSCOREINTEGRATEDSCOREtraditionalcategorySCOREheavyRAINFALLGAUSSIANweightfunction

分类号： P456.7[天文地球—大气科学及气象学]