Evolution Characteristics of Precipitation Structure and Urbanization Effect in Plateau Mountainous Cities:Case Study on Kunming City
To investigate the precipitation structure evolution in plateau mountainous cities during urbanization,ex-emplified by Kunming City,we employed the Mann-Kendall test and R/S analysis to quantitatively examine the e-volving characteristics of various precipitation structures and urbanization impacts.Results revealed the following:(1)Between 1960 and 2017,Kunming City exhibited a decreasing trend in annual precipitation and frequency,al-beit an increasing trend in precipitation intensity.Notably,two distinct high-precipitation zones appeared in the main urban area and downwind region of Kunming.(2)Nighttime and daytime precipitation occurrences were com-parable,with slightly stronger contributions and intensities observed during nighttime.Heavy nighttime precipitation events exhibited a trend of escalation.Summer and autumn dominated the yearly precipitation,with intensities in these seasons on the rise.As precipitation grades increased,the occurrences decreased exponentially,contribution rates changed quadratically,and intensity increased linearly.The transition from diminishing weak precipitation e-vents to escalating heavy ones characterized the change of precipitation grade structure.(3)Urbanization exerted varying impacts on annual precipitation,frequency,and intensity,with respective RCU of 10.62％,-0.91％,and 11.32％.Urbanization bolstered annual precipitation and intensity while tempering frequency,primarily through di-minished winter precipitation days and light rain days.Urbanization disrupted diverse precipitation structures,con-centrating heavy precipitation in summer,autumn,and nighttime,diminishing light events,and markedly intensif-ying extreme heavy precipitation occurrences.
precipitation structureevolution characteristicstime scaleprecipitation gradesurbanization effectKunming City
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