威海地区大风警报及大风黄色预警中南北风特征对比分析OA

In Weihai,a coastal region with frequent gale events,accurate discrimination for gale warning grading poses great challenges.The spatiotemporal characteristics and discriminant thresholds of northerly and southerly winds under different warning levels and synoptic patterns remain unclear,which restricts the refined graded gale early warnings and meteorological service quality over coastal areas.To accurately identify the evolutionary laws of gale weather in the Weihai region and quantify discriminant indicators for graded early warnings,this paper adopts nearly 10 years of upper-air and surface observation data,as well as ERA5 reanalysis datasets of the Weihai region.Using comparative analysis,this study systematically investigates the characteristics and discrepancies between northerly and southerly winds under different warning grades and synoptic patterns.The main conclusions are summarized as follows.(1)Spatiotemporal distribution characteristics:The seasonal distribution patterns of the northerly and southerly winds are similar between gale notification alerts and yellow gale warnings,with remarkable differences in diurnal variation and spatial distribution.For gale notification alerts,the high-frequency areas of average northerly and southerly winds present distinct spatial preferences and a bimodal diurnal variation pattern.For yellow gale warnings,gusts mainly concentrate in the northern and eastern coastal zones.The diurnal variations in the northerly and southerly gusts show trimodal and bimodal patterns,respectively.(2)Synoptic systems and threshold characteristics:Synoptic systems corresponding to yellow gale warnings feature stronger overall intensity and coverage closer to the Weihai region.Meteorological parameters differ substantially among various synoptic patterns.For the post-cold-front northerly wind pattern,the central pressure of the cold high can reach up to 1045 hPa,dominated by northwest cold air transport with larger pressure gradients.For the cyclonic southerly wind pattern,the central pressure drops to as low as 993 hPa.Typhoons with different tracks show obvious disparities in moving paths and central pressures.Furthermore,key meteorological factor thresholds significantly vary across warning levels and synoptic types,which can serve as quantitative criteria for judging wind intensity and distinguishing warning grades.Overall,this study establishes the correlation between northerly and southerly wind characteristics and gale warning grades in the Weihai region,clarifying high-incidence zones,temporal evolution features,and quantitative thresholds of key meteorological elements for graded gales.The findings can provide solid scientific support for precise graded gale forecasting,refined meteorological services,and disaster prevention and mitigation in the Weihai region.