青海省东北部近41a降雹持续时间时空分布特征及影响因子研究

利用青海省东北部11个地面观测站1980-2020年的降雹和高空资料,分析了降雹持续时间的时空分布及海拔、气温、相对湿度、0°和-20°高度层变化对降雹持续时间的影响。结果表明：近41a青海省东北部站点平均单次降雹持续时间的最大值出现在化隆县,高达9 min,最小值出现在同仁县,仅为4.89 min；年平均降雹持续时间以0.9 mim/10a趋势下降,持续时间小于9 min频率最高,占总观测次数的73.55 %；降雹持续时间月变化明显,日变化呈单峰型,峰值出现在午后16时,占总降雹累计持续时间的19.12 %；降雹持续时间与海拔高度呈显著的正相关,相关系数高达0.81(通过α=0.05显著性检验)；降雹持续时间的减少与平均气温升高、0 ℃和-20 ℃层高度升高、气温日较差及相对湿度的减小相关。

Study on temporal and spatial distribution characteristics and influencing factors of hail duration in northeastern Qinghai Province in recent 41years

Based on the hail and upper-air data from 11 ground observation stations in northeastern Qinghai Province from 1980 to 2020, the temporal and spatial distribution of the duration of hail fall and the influence of altitude, temperature, relative humidity, 0 ° and - 20 ° height changes on the duration of hail fall are analyzed. The results show that the maximum value of average single hail duration at stations in the northeast of Qinghai Province in recent 41 years appears in Hualong County, up to 9 min, and the minimum value appears in Tongren County, only 4.89 min. The annual average duration of hail falls with a trend of 0.9 mim/10a, the frequency is the highest when the duration is less than 9 min, accounting for 73.55% of the total observation times.The monthly variation of hail duration is obvious, the daily variation shows a single peak type. The peak value appears at 16:00 p.m., accounting for 19.12% of the total cumulative duration of hail.The duration of hail fall is significantly positively correlated with the altitude, and the correlation coefficient is as high as 0.81 (by α= 0.05 significance test).The decrease of hail duration is related to the increase of average temperature, the rise of 0 ℃ and - 20 ℃ layer height, the decrease of daily temperature range and relative humidity.